Tuesday, 22 December 2009

Christmas trees: Don't let them stay past 7th night

A small study carried out in 2007 identified fresh natural Christmas trees as a source of mold in the domestic environment.

Twelve times during a two week period, researchers measured mold counts in a room containing a live Christmas tree, beginning when the tree was brought inside and decorated. The tree was located 10 feet from a heat vent, and the indoor temperature was maintained at between 65 and 68 degrees.
For the first three days, counts remained at 800 spores per cubic meter of air, then began escalating, rising to a maximum of 5,000 spores per cubic meter by day 14, when the tree was taken down.
Airborne mold spores are known to be an irritant to people sensitised to mold spores and this could have a bad effect on the health of people suffering from severe allergy, allergic bronchopulmonary aspergillosis (ABPA) and others.

For those people perhaps an artificial tree is the best idea. If artificial Christmas trees are not acceptable then make sure the tree is removed from the room after a week at the most and ensure that the tree has been cut very recently (they are often cut more than a week in advance)!

Merry Christmas to one and all!

Thursday, 17 December 2009

Aspergilloma & biofilms

Aspergilloma are characteristically balls of fungi contained within cavities in tissue. Most commonly this is in lung tissue, often thought to be formed in pre-existing cavities as most patients seem to have a history of lung damage e.g resulting from tuberculosis.

Aspergilloma can be treated with antifungal medication but this is usually as a way to contain the fungal ball rather than to try to eradicate it - the ball can be very resistant to systemic medication and a cure often requires its complete removal.

Why is a fungal ball so difficult to penetrate? One reason is possibly that there is no circulation of blood through the ball so there is nothing to carry the drug into the ball. Another reason is becoming clearer as the latest research starts to offer clues.

Many micro-organisms are known to secrete a tough slimy substance under some growth conditions and to aggregate together to form a biofilm (see fig). Some are known to do that in response to antibiotics, as if there is some protection to be had from this structure.

It has been known for some time that Aspergillus fumigatus forms a biofilm when growing on an agar surface (Beauvais et al., 2007). This paper shows that the biofilm is produced at the surface of an aspergilloma while growing within the human patient. The fungal ball largely consists of what look like dead fungal hyphae with some viable cells at the periphery of the ball - the structure of the dead hyphae are reminiscent of fungi that have used up all available nutrients and died.

Could it be then that the ability to get an antifungal drug within the fungal ball is not as important as it would be to just penetrate the surface as most of the deeper lying cells are already dead?
Why isn't this happening already as that is where the richest blood supply exists already?
One reason is that the biofilm slime is notoriously impermeable to antifungal drugs - once we can get antifungals through that barrier we might be making headway.

Loussert et.al. show that A.fumigatus growing on an agar plate produces a different biofilm slime compared with when it is growing as an aspergilloma. When it grows within a lung as an aspergilloma it produces extra components. When it grows as an invasive aspergillosis (not as a ball) it produces a biofilm slime but the slime is different when compared with that associated with an aspergilloma.

Biofilms are well known to have a role in resistance to antifungals (d'Enfert. 2006) so perhaps they are performing the same function for aspergillomas? Careful attention is needed to assess which antifungal drugs are better at penetrating the type of biofilm secreted by an aspergilloma, and which are likely to penetrate the slime produced by an invasive aspergillosis.

Friday, 11 December 2009

Use of copper fittings to reduce microbial contamination

The environment we live in direct contact with is thought to be a major 'store' for infection. Surfaces we touch can easily provide a route for cross-infection from patient to patient in hospitals.

Examples of surfaces that can carry infection include taps, toilet flush handles, toilet seats, door handles and so on. Traditionally these are made from metal and usually from stainless steel as this has been seen as providing a very easy to clean surface which get frequent disinfection via wiping with a disinfectant.

This study carried out at Selly Oak Hospital in Birmingham, UK showed that replacing door handles, toilet seats and taps with copper fittings markedly reduced the microbial contamination of those surfaces.
The copper has been shown to be toxic to many microbes including Aspergillus and other fungi, preventing growth and killing any fungi or bacteria that land on them without the need for additional antiseptic fluids.

The implications of this finding go beyond touchable surfaces as it is known that mould growing within poorly maintained air conditioning units can be a major problem. Perhaps components like these could be made out of copper or coated in copper as a precaution?
Perhaps sink traps and other fittings used in hospitals should be made out of copper instead of plastic?

Tuesday, 1 December 2009

Antifungal drug resistance caused by agricultural use of azoles?

Azole antifungals (itraconazole, voriconazole, posaconazole) are depended on in medical clinics to treat fungal infections. They are effective but the nature of the infection often means that the patients has to take the medication for long periods of time. Improvement is usually achieved but after a while progress can slow and it is often found that a strain of the fungus has grown out which is resistant to that antifungal drug.

Fungi can develop resistance to antifungal drugs naturally over time but it is a rare event and once it happens there is no know mechanism for the fungus to transfer the resistance genes to other fungi - something that is common in bacteria. This limits the frequency of resistance arising anew in fungi.

Where does the resistance come from? For resistant strains to multiply the fungus must come into contact with antifungals and thus encourage resistant strains grow out. Apart from in a patient undergoing antifungal treatment where does that happen? A recent paper (Science 326:1173 (2009)) strongly suggests that one place that this happens is when crops are treated with antifungal azoles in order to prevent fungal spoilage. Antifungal azoles are known to be used on a very large scale on orchards, vineyards and some grain crops in europe so this would be a good place for resistance to emerge.

Spores from strains of Aspergillus that are resistant to some antifungals have been found close to Radboud University Nijmegen Medical Centre in the Netherlands suggesting that they could be breathed in by patients. The type of mutation found in fungi that infected patients was also found in most of the fungi isolated outside the hospital in soils.  This adds up to a strong possibility that those patients breathed in fungi that were already resistant to the antifungals used in the clinic when they were breathed in. 94% of the clinical isolates at Nijmegen and 69% at other Dutch centres carried the same mutation, suggesting a single event or single cause of the resistance found.

The situation in Radboud University Nijmegen Medical Centre seems to be different to that in the National Aspergillosis Centre Manchester, UK as in Manchester there was a range of different mutations in strains which suggested that there were several different original events that caused those mutations.

The true situation is still not completely clear and the results found in the Netherlands might not be representative of the pattern of resistance everywhere but as the original paper states, this is enough to require us to think carefully about allowing the large scale use of azoles in agriculture.

Thursday, 26 November 2009

After every flood comes an even more damaging blight: mould

In a week that has seen extensive flooding in the UK and Ireland it is timely to look at the damage caused by moulds growing on all the damp materials left when the floodwaters recede. Many materials including building materials such as plasterboard will absorb and hold on to water long enough to allow the growth of moulds. They are difficult to dry out and it only takes 48 hours of damp to result in large amounts of fungal growth particularly in places where little sunlight shines.

So what next?
Clearing up is largely a case of throwing out all materials that are mouldy and cannot be cleaned e.g.soft furnishings, carpets, clothing, units and furniture made out of chipboard, wallpaper. Drying out homes as quickly as possible is a high priority as moulds can grow in hidden cavities and prefers to keep out of the light.
There are extensive instructions on how to clean up here - on the right hand side under the heading 'Emergencies: Floods and Hurricanes'.

Health Effects
There are many potential health effects of living in a damp mould affected house and the discussions on this subject are plentiful. There are two recent review publications that go into this subject in some detail, both published this year (2009), the first one being written by a prominent fungal researcher who herself  lives in New Orleans and whose home was flooded:

Here in the UK we have the National Aspergillosis Centre which specialises in the treatment of all aspergillus infections and is closely affiliated with the Regional Mycology Laboratory in Manchester which has a large amount of expertise in the investigation of indoor mould. RML is run by Professor Malcolm Richardson who advised the World Health Organisation on indoor health effects of  fungi amongst others and is a Professor of Medical Mycology at Manchester University.
The US have a (voluntary) certification scheme for mold remediating companies, many run by the Indoor Air Quality Association. The Environmental Protection Agency have a listing of the associations involved here.

Thursday, 19 November 2009

Aspergillus provides a solution to grapefruit juice interacting with medications

Grapefruit juice has been shown to interfere with absorbtion and/or metabolism of several prescription drugs with potentially hazardous consequences in some cases. The effect can be either to increase or lower the amount of the drug circulating in the blood of the patient, so if a drug such as one meant to lower blood pressure was taken with grapefruit juice the effect could be to reduce blood pressure too much (see here for more examples).

The aim of drug management is to find a dosage level which causes blood levels to stay within a useful range for each patient. It is not hard to imagine a patient unaware of the interaction between grapefruit juice and their medication might take a glass of grapefruit juice with their drug causing drug blood levels to increase. When the juice carton is empty they might use a different drink causing levels to drop again resulting in much confusion on the part of their doctor over what the right dose for them is!

There is clearly some benefit to understanding what component of grapefruit juice is important for this interaction and in removing it from grapefuit juice offered for comsumption. It is already known that one factor is furanocomarins (FC) which inhibit the enzymatic activity in the liver of patients that activates some drugs, so one aim is to remove FC's from grapefruit juice.
The United States Department of Agriculture (USDA) have made some progress in this regard. They have identified fungi that can remove or inactivate FC's from grapefruit juice and are in the process of finding out how the fungus does that.

It is ironic to note that the fungus used at the USDA is Aspergillus niger. Aspergillus (more usually fumigatus) causes a serious infection known as aspergillosis. The infections are treated with antifungal drugs in an attempt to eradicate the fungus. Once such antifungal is itraconazole and itraconazole is one of those drugs that interact with grapefruit juice, enhancing the effective dose.One species of Aspergillus is helping counteract the pathogenicity of another!

Wednesday, 11 November 2009

Identification of new fungal protein "TmpL" which shields A.fumigatus and assists with the infection process.

Researchers at the Virginia Bioinformatics Institute (VBI) at Virginia Tech and Montana State University have discovered a fungal protein that plays a key role in causing disease in plants and animals and which also shields the fungal pathogen from oxidative stress. The protein was identified in both Alternaria brassicicola (which causes much crop damage) and Aspergillus fumigatus a human pathogen, which can cause death in immune compromised people.

Reactive oxygen molecules are known to be important in fungal development and virulence.

The researchers have found that a fungal protein called "TmpL" is critical for the infective process of host tissue and helps the fungal pathogen regulate oxidative stress responses-inflicted upon as a result of the host immune response to infection.
The current study shows that TmpL is essential for both types of fungi to cause disease in their host cells. Dr. Kwang-Hyung Kim at VBI, the lead scientist working on the project, remarked, "TmpL appears to be located in the membrane of the Woronin body, a specialized peroxisomal organelle found specifically in the cells of hyphae in filamentous fungi. When the function of TmpL is impaired or its gene inactivated, both A. brassicicola and A. fumigatus show drastic decreases in their ability to cause disease in the experimental host systems of cabbage, Arabidopsis, and the mouse. Deletion of the TmpL gene also makes the fungi extremely sensitive to oxidative stress in the lab."

Dr Lawrence at VBI said: "In this study, we provide the first evidence that a certain type of disease-related protein from both a plant and animal fungal pathogen is critical for protecting the pathogen and for causing infection of healthy host tissue. As such, this protein represents a good starting point as a potential target for the development of efficient and novel therapeutics for both plant and animal fungal diseases."
more information

Thursday, 5 November 2009

Merck merge with Schering Plough for $41 billion

Merck (manufacturer of the antifungal drug Caspofungin) and Schering-Plough (manufacturer of the antifungal drug Posaconazole) have merged their companies to form a single company that will operate under the name Merck. The merger has cost Merck over $41 billion.
The merger was initially announced in March 2009 and has taken 8 months to complete.

The new company will have a combined revenue of $40 billion with savings of $3.5billion a year due after duplicated jobs are removed. It will have 15 candidate drugs being developed for market in the near future and will be employing people in 140 countries. Over half of its revenues will be earned outside the US.

How will this help the consumer?
Drug development is a hugely expensive business with billions of dollars at stake in every drug in late stage development. Billions of dollars have to be invested in the development of every drug and every drug can still fail vital tests after years of expensive development, losing vast amounts of money.
Some drugs are more likely to fail than others so smaller companies are more likely to concentrate on the 'sure thing' in order to avoid catastrophic finacial losses.

As a larger company the new Merck will now be able to do more 'risky' drug development as it will be able to absorb more financial risk. It will be able to investigate treatments for markets in which there are less well defined targets in the hope of the higher financial returns that they could bring.

Some illnesses effect smaller numbers of people but still require huge investment with which to develop new drugs to treat those illnesses. The consequent return is smaller as it can only be sold to fewer people. These drugs are less likely to be made by smaller companies as the potential return is lower. People needing treatment for rarer illnesses such as aspergillosis should be encouraged that they are more likely to be given new treatments in the future as a result of this merger.

Friday, 30 October 2009

Woman beats invasive aspergillosis to get married

Trish Dunlop was hit with the devastating news that she suffered from the same leukemia that killed her mother some years before. Fearing the worst she attended hospital for treatment. During chemotherapy her long term partner Will proposed and they resolved to marry soon.

Trish was diagnosed with Acute Myeloid Leukemia (AML). Long term recovery from AML varies according to a number of factors and can be as high as 50-70% for some groups of patients but overall a recovery rate of 20-30% is currently achieved. Trish had her work cut out to survive this cancer.

Unfortunately the worst was yet to come. Some types of leukemia cause a severe weakening of the patients ability to fight off infections. After 3 rounds of chemotherapy her body was weak and her immune system weaker still. She fell victim to an aspergillosis infection in her lungs. Aspergillosis is tough to treat at the best of times but if the patient has a weak immune system they are particularly up against it in the fight for survival. Things looked bleak when her doctors could do no more and early in December 2008 gave her 2 hours to live.

2 days later Trish woke up on the anniversary of her mother's death. From that point on she gradually improved, beating back both AML and aspergillosis. She left hospital a month later and was married six months later in the summer of  2009.

This is a good news story but it was a close run thing. Presumably Trish's body recovered enough of its immune system just in time to beat back the fungus. The message is that there is always hope even in the direst of circumstances, never give up hope.

Friday, 23 October 2009

Itraconazole: how much is too much?

Itraconazole is an antifungal that is known to cause a range of adverse 'side effects'. It is also an important weapon in the clinicians armoury against aspergillosis and other fungal infections, so how do we find out how much to use without causing excessive side effects?

Dose of itraconazole is often difficult to judge accurately as there are several variables which effect blood levels of the drug (e.g. variable absorption from patient to patient) so it is important to base dosage studies on actual levels on the blood. A paper by Lestner et.al. goes one step further  to ensure accuracy by using a sophisticated bioassay to measure levels of active itraconazole rather than simply measuring levels of the chemical present in the blood. The chemical is often only partly active so measurement of active itraconazole is a more reliable measurement of real dose.

Using this assay Lestner et.al. demonstrated that a level of 17.1mg/L of itraconazole and above was the point at which side effects started to become excessive.

Wednesday, 14 October 2009

Over 90% drugs sold online are fake or illegal

This report by EAASM looks at the widespread trade in prescription drugs over the internet. In many countries supply of these drugs are strictly controlled, partly because they can be very dangerous when not taken with the advice of a medical doctor but also partly because it is important to control quality - if a particular batch of a drug is found to be causing unexpected problems it can be withdrawn from public consumption.

Unfortunately these drugs can be very expensive when purchased via normal routes, or not available at all if the health authority budget cannot pay for them. Websites offering what are apparently the same drugs at much lower prices then become a tempting proposition for some and many might for example supplement drugs they have been prescribed with a much cheaper supply purchased over the internet.

Why are these drugs cheaper when purchased over the internet? The group who published this report purchased 30 different drugs from over 100 of the websites who supply prescription drugs, ignoring those that were obviously fraudulent. Quoting the article:
  • 62% of medicines purchased online are fake or substandard

  • 95.6% of online pharmacies researched are operating illegally.

  • 94% of websites do not have a named, verifiable pharmacist.

  • Over 90% of websites supply prescription-only medicines without a prescription.

So legality apart, over six out of ten of the purchased drugs were fake or of poor quality. At best they would do nothing but considering many of these were vital for life threatening conditions doing nothing could be lethal. The substances used to make the fakes were also found to be toxic in some cases.
Equally dangerous is that very few of these companies asked any questions about the health of the person ordering the drugs or what else they were taking - again with potentially lethal consequences. Most drugs supplied did not arrive with so much as an information leaflet for the patient to read - though many of these are also available online it isn't easy be sure to find the right one.

One of the comments I have read on this issue was that these drug suppliers are providing a valuable service to the lower paid. Drug companies are also said to be profiteering when a drug can be purchased in an adjacent country at far lower prices. The answer to this is clear, these drugs are cheaper because they aren't what you think they are, they come with little or no medical advice and if they are the drug you purchased they are most often out of date and/or stored under poor conditions leading to important dosages lacking consistancy.

If you value your health at all this isn't the way to save money.

Wednesday, 7 October 2009

Hurricane Katrina Victims are Contaminated by Mycotoxins

Hurricane Katrina devastated large numbers of homes that lay in its path when it made landfall in 2005. It was the sixth largest hurricane on record in the Atlantic and the most costly and deadly in the history of the United States with over 1800 people losing their lives.
Tens of thousands of homes were severely effected by extensive flooding and as a result of the warmth and moisture moulds grew rapidly inside houses. In these conditions moulds can start producing mycotoxins within a few days of the initial flooding.

Over the next few months people fell ill with a variety of symtoms that could be consistent with exposure to moulds e.g. asthma, memory loss, fatigue, headache, muscle pains or weakness etc. These are not universally agreed to be related to mould exposure as they tend to be considered to be a collection of rather vague symptoms for which there is no tool to measure.

Mycotoxins are known to be highly toxic when present in sufficient amounts (there is a lot of data on animals fed with contaminated food) so there is a movement to consider whether or not mycotoxins could be causing those symptoms thought to be related to mould exposure.

This paper published recently examined the levels of mycotoxins in people exposed to moulds after Katrina. There had been no easily available tool to measure the levels of mycotoxins in the bodily fluids and tissue samples from people thought to have been exposed to moulds but this paper addressed that shortcoming and demonstrates the usefullness of several methods not only to detect the presence of mycotoxins but also to detect the levels of several different types of mycotoxin in several different tissue types.

Levels exceeding 2 parts per billion (up to 18ppb) of several different mycotoxins were detected in people suffering 'mould exposure symptoms' and these were compared with no detectable mycotoxins in control unexposed individuals.
Mycotoxins are therefore proved to be detectable in the Katrina victims in this study - so have they made these people sick?

Unfortunately we still do not know the answer to that question.

2-18ppb is well below mycotoxin levels known to cause acute or cumulative mycotoxin poisoning in animal models. We cannot yet rule out toxicity caused by long term exposure to these levels of mycotoxins, or exposure to a cocktail of different toxins, both of which may well have effected this group of people but evidence is not yet ready to confirm or dismiss the possibilities.

At least as a result of this work we now have some of the important tools with which we can start to answer these questions.

Monday, 28 September 2009

£2.2 million funding for research into antifungal drugs

Massive new funding by the UK government into researching new antifungal drugs was announced today. This is a further commitment to the funding already in place (£2.3 million) for several projects looking for new antifungals (aka antimycotics) or new targets for future antifungal drugs - see the Medical Research Council webpages for further details.

The new funding is to look for new targets in Aspergillus fumigatus for antifungal drugs to attack, thus making possible new types of antifungal drugs to fight alongside established drugs that are currently in use such as itraconazole, voriconazole, posaconazole (all of which use similar targets) and amphotericin.

The funding is being given to the van Aalten laboratory in Dundee, Scotland, UK for a period of five years and will pay for a team of five researchers to conduct a sustained project of basic research under the supervision of Prof van Aalten. The van Alten lab has an extensive publication record in molecular and structural biochemistry so will be able to use this wealth of experience and excellent facilities to progress the projects aims.

Once targets are identified by this basic research this location has the added advantage of also hosting a large Drug Discovery Unit dedicated to the gereration of new drugs - progress will be uninhibited by any shortage of expertise or facilities!

Thursday, 24 September 2009

Valerie & John Evans donate birthday presents to the Fungal Research Trust

The Fungal Research Trust have funded many research projects over the last 18 years (see charity number 1003361 on the Charity Commision website) spending over £300 000 in 2008. Net administrative spending was 1.3% in 2008 so this is a highly efficient charity spending money where it counts.

Published papers resulting from research funded by the FRT are many and are listed here.

The FRT supports several initiatives to support people suffering from aspergillus infections in collaboration with the new National Aspergillosis Centre, taking over many of the aspirations of the now defunct Aspergillus Trust. The FRT runs a large patient support group (Aspergillus Support) and supports a large website that provides information for patients (Aspergillosis Patient Support).

The FRT is totally supported by donations so every pound donated counts towards future research into aspergillosis and future patient support projects. Personal donations are particularly touching and welcome so when John Evans decided to donate his birthday presents to the Trust it was more than welcome.
John and his wife Valerie are pictured above handing a cheque to the Director of the National Aspergillosis Centre Professor David Denning who is receiving the cheque on behalf of the Fungal Research Trust.

Donate to the Fungal Research Trust

Wednesday, 16 September 2009

Gabby comes home

Gabby is a male osprey raised as part of the recolonisation efforts at Lake Yankto, Ohio. Sometimes known as the 'fish eagle' this impressive raptor has been the subject of many successful projects to restore them to their wild homes in many locations across the world(US, UK, Spain) after a serious decline in population during the 1960's & 70's due to the overuse of the insecticide DDT.

Gabby, like many birds of prey is susceptible to aspergillosis when stressed and Gabby fell prey to this infection while a very young bird in captivity. He recovered after being treated at the restoration project centre but has since had to be rescued on several occasions after attempts to return him to the wild failed. After nine attempts he will now be kept permanently at the centre and play his part in the project by helping educate the public of the importance of preserving these birds.

Monday, 7 September 2009

Clever cloak prevents immune recognition of airborne fungal spores

Recent scientific work published in Nature in August, has illuminated the means by which inhaled spores of aspergillus avoid recognition by the immune system. The air we breathe is loaded with many types of fungal spores but it is not known why inhaling these spores does not continuously activate the host's immune system and promote a detrimental immune inflammation. So the spores (or conidia) must have a means of evading the immune system.

The spore surface of many fungi is covered with a layer of regularly arranged fibres known as the rodlet layer - in Aspergillus species this layer is responsible for a high level of hydrophobicity - composed of the hydrophobic RodA protein covalently bound to the conidial cell wall.
In laboratory studies, RodA when extracted from aspergillus conidia, did not induce activation of immune cells in vivo - it appears to be immunologically inactive. However when the rodlet layer was removed either chemically or genetically using a mutant strain - the modified conidia stimulated immune responses. All the scientist's observations indicate that the rodlet layer on the conidial surface acts as an invisibility cloak - so far as the human immune system is concerned.

Interestingly during germination of conidia, the RodA protein appears to be degraded, exposing the underlying immunogenic cell wall components usually masked by this rodlet layer. So germinating spores will evoke immune responses in an individual.

Aspergillus makes it to the movies

In the newly released Pedro Almodovar film "Broken Embraces" a young boy is treated in Madrid for aspergillosis. The film is an intense tale of passion and tragedy - a Spanish film with subtitles.

Monday, 24 August 2009

Risk of Mycotoxins Associated With Hail Damaged Corn

There is very little risk of infection of most agricultural plant crops unless the crop is damaged or stressed in some way. In a way this is similar to animals and people - aspergillosis can only take hold if the person or animal is already vulnerable to infection in some way.

In crops like maize and other 'grass-like' plants the major stress can often be shortage of water while the plant is growing or too much water during harvest time (which makes the harvest damp and requires that it is dried before storage).

There are other stresses that the farmer has to contend with in order to ward off Aspergillus and other fungi and one of those is physical damage. If a leaf breaks off or is bruised the 'wound' can be vulnerable to infection, so it is easy to see that if a crop is subjected to heavy hailstorms at the wrong time during its growth cycle (e.g. as the head or fruit is becoming quite large or ripening) then hailstones, if large enough, can severely bruise the crop. Aspergillus can readily then infect the damaged parts.

This story covers that risk, and the consequential risk of mycotoxins should the crop become infected with mycotoxin-synthesising Aspergillus to a large extent.

Friday, 21 August 2009

Tobias M. Hohl honoured for work on Aspergillus fumigatus

More recognition for work carried out on Aspergillus has been announced.

Quote from the American Society for Microbiology website:

Tobias M. Hohl is honored for his research on the interaction of Aspergillus fumigatus and the pulmonary innate immune system. Hohl earned his M.D.- Ph.D. from the tri-institutional program of Weill Medical College and Graduate School of Medical Sciences of Cornell University, Memorial Sloan-Kettering Cancer Center, and Rockefeller University, New York. While a Research Fellow at Memorial Sloan-Kettering Cancer Center, Hohl studied chemokine induction and signaling pathways in macrophages exposed to A. fumigatus. He learned that Dectin-1, a receptor expressed on dendritic cells and macrophages, binds β-glucans on the surface of germinating A. fumigatus conidia. Hohl showed that β-glucans are expressed in state-specific fashion on geminating A. fumigatus, thereby, restricting the inflammatory response to germinating but not dormant fungal spores.

His work demonstrated for the first time how the mammalian immune system recognizes Aspergillus infections; it was published in PLoS Pathogen.

Friday, 14 August 2009

Experimental evidence that antibiotics can trigger allergy & asthma

Role of antibiotics and fungal microbiota in driving pulmonary allergic responses

It has been hypothesised (the "hygiene hypothesis") over the last few decades that the taking of antibiotics has a role in the increase in asthma and allergy observed over the same time. This paper describes the creation of a mouse model for antibiotic-induced disturbance of the microbial flora in the gut. Once the mice have been given antibiotics they become susceptible to an allergic airway response to stimulus by Aspergillus fumigatus spores. If the mice are not given antibiotics they do not develop the allergic response.

This is the first experimental demonstration that antibiotics and gut flora can influence allergic airway disease, and highlights the concept that events in a distant mucosal site such as the gut can play an important role in regulating immune responses in the lungs.

Friday, 7 August 2009

Mold-free tea

Tea plant
There are some specialist teas that are fermented by Aspergillus and this has apparently led to a widespread misunderstanding amongst those people who consider themselves to have problems eating food that contains some Aspergillus material or other molds. They are tending to avoid all teas as potentially containing traces of Aspergillus.

This article points out quite rightly that most tea sold in the western world is not fermented using Aspergillus but is in fact prepared using a quite different process called 'oxidation' - a mold free process where crushed leaves are left for their internal enzymes to carry out the natural oxidation process for varying amounts of time (adjusted according to the final taste required) and are then heated to stop the oxidation and dry out the leaves. The timing of the heating and drying stage is crucial to prevent mould growth.
We wrote an article on this issue some time ago and noted at that time that most tea is made by a mold-free process.

Having said that it would be very difficult to describe tea as an 'Aspergillus-free' drink as by its nature it is plant material that will be exposed to Aspergillus at various times in its life so the leaves will always be likely to hold some Aspergillus spores.
In fact the same would go for most plant foods as Aspergillus is an important component of soil and most plant material will have been in contact with soil and windblown soil. The amount of mold contaminating the plant material is probably very small and some will probably be washed off during preparation but will still not be completely free of Aspergillus material.
This is not a problem for most people and we have no reliable information telling us that anyone is badly effected by eating plant food carrying this much Aspergillus - even those who have increased allergy to this fungus.

Fermented teas are of course completely different. They have been cultured with the mould and will contain many thousands of times more Aspergillus material compared with non-fermented tea.

Wednesday, 22 July 2009

Malaria causes aspergillosis

Plasmodium falciparum ring-forms and gametocytes in human blood.
A case of a malaria sufferer who subsequently developed aspergillosis has been reported in the scientific media.
Malaria is caused by the invasion of the victims blood by tiny parasites called Plasmodium with several different species being involved. These parasites multiply within the red blood cells of the host causing a variety of symptoms including anaemia (i.e. lack of red blood cells), fever, chills, nausea, flu-like illness, and, in severe cases, coma, and death.
The disease is carried by one particular type of mosquito and is a major health problem in some parts of the world, mainly sub-saharan Africa. One to three million people a year die of malaria with hundreds of millions infected. It is known that one of the mechnisms that the malaria parasite uses to avoid being detected and removed by the hosts immune system is to
inhibit at least on part of the immune system - phagocytes.

cannot normally infect people with normal, efficient immune systems. Even if that immune system is damaged Aspergillosis (i.e. infection by Aspergillus) is not common and is very rare except in the most extreme cases of immunocompromisation e.g. after transplant or during treatment of some cancers - malaria does not cause extreme immunocompromisation.

In this case however a patient who is otherwise completely healthy but who has malaria has become infected and there are four other cases quoted, all of whom died. In this case the patient was successfully treated with an antifungal medication and completely recovered. This is the first recorded incidence of a successful intervention of this type of case.

More oral amphotericin developments

Old dog (new trick?)
We featured a story a few months back which was based on the development of a variant of amphotericin which could be taken by mouth rather than as now by intravenous injection (IV). There are a number of advantages to taking a drug orally, not the least of which is convenience for the patient (they can administer their own drug at home) but also includes reducing the number of visits to hospital as IV has to be done under close medical supervision.

It turns out that there is more than one oral amphotericin drug under test. This article mentions a drug currently known as iCo-009 which has already been extensively researched (though it looks like all of the currently published work is based on animal models) and found to be promising. Human trials are the next step.

There is more work to do before this or other new variants of amphotericin B comes to the clinic but these are hopeful signs of the development of new uses for older drugs which can only be a good thing for all concerned.

Tuesday, 21 July 2009

Recognition for Aspergillus expertise

Rob Samson - Honorary Doctor of Swedish University of Agricultural Sciences (Uppsala)
The Swedish University of Agricultural Sciences in Uppsala confer on Prof. Dr. Rob Samson the degree of Honorary Doctor of Agricultural Sciences at the Faculty.

The Faculty's motivation is as follows: Dr Rob Samson, CBS - KNAW, Utrecht, Holland is a world leading specialist on the taxonomy of Aspergillus and Penicillium species. Some of these fungi occur as spoilage organisms and potential mycotoxin producers in food and feed. Other species have important roles in the biotech industry, while still others are used in the production of mould-fermented foods (roquefort and camembert cheese, salami and soya sauce). A correct identification to species level is essential for bom food safety and industrial process quality.

Dr Samson has developed stable taxonomic systems based on morphological, chemical and molecular criteria mat are fundamental to fungal identification. His basic research in fungal taxonomy has led to studies of Aspergillus and Penicillium in relation to food, biotechnology, indoor air quality and medicine. Dr Samson has organised international courses on "Identification of food-borne fungi" with numerous SLU participants.

He has also written richly illustrated textbooks that are used by hundreds of SLU students every year. In conclusion Dr Samson's research and pedagogic skills are of excellent international Standard, which has been and will be of large and central importance for the faculty. The conferment ceremony, will take place in Uppsala October 3 2009.

Friday, 17 July 2009

Drug resistance fears over killer fungal disease

Treatments for the most common airborne fungal disease are proving less effective due to increased resistance to the anti-fungal drugs used to combat infections.

Aspergillosis is an incurable disease of the lungs caused by fungal Aspergillus. It is treated using compounds called azoles but researchers at The University of Manchester have found that the fungus has been able to mutate making treatment ineffective.

The research, published in the prestigious US journal Emerging Infectious Diseases, showed that 13 out of 14 affected patients recently treated by the team did not respond to therapy and that numerous mutations were responsible.

Lead researcher Professor David Denning, whose clinic is based at the University Hospital of South Manchester, said that most of the fungus strains, or isolates, were completely resistant to all oral antifungals, leading the doctors to resort to long-term intravenous therapy.

"While the very first azole-resistant isolates were identified in the late 1980s in California, the first UK resistant Aspergillus wasn’t found until 1999 and now we have dozens,” said Professor Denning, who is Director of the National Aspergillosis Centre.

“Antifungal resistance rates have been rising since 2004 and stood at 17% in 2007, a trend that has continued into 2008 and 2009. Patients from all over the UK were found to have resistance, mostly related to long-term treatment of incurable Aspergillus disease."

In 2008, workers in Nijmegen in the Netherlands reported a similar rise in resistance, related to a single resistance mutation, also found in Aspergillus grown from soil. They suggest that extensive azole use in agriculture may be responsible. About one third of all fungicide use in farming is azoles.

Currently, the only class of antifungal that can be used orally for Aspergillus infection and allergy are the azoles, principally itraconazole, voriconazole and posaconazole.

“We also found cross-resistance to voriconazole (65%) and posaconazole (74%) in those isolates we tested that were resistant to itraconazole,” said Professor Denning. “The result depends on the particular mutation conferring resistance.

“Patients can be treated with intravenous amphotericin B or caspofungin, but these are not useful when patients leave hospital, or have allergic aspergillosis."

Report we quote was published in full by Manchester University

Wednesday, 8 July 2009

First trial for new antifungal begins

It has been mentioned elsewhere in this blog that the search for new antifungals is important and ongoing. Particularly important are antifungals that have different modes of action when compared to existing antifungals so it is encouraging that a local company here in Manchester, UK have announced the first tests are under way of their new antifungal which has a novel target of activity:
F2G Limited, the Manchester UK based antifungal drug discovery and development company, today announced the initiation of a Phase I clinical study of FG3622, the company’s lead antifungal drug candidate.

The Phase 1 trial is a randomised, placebo-controlled study designed to evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of FG3622. 100 healthy volunteers will be enrolled in the trial which will evaluate single as well as multiple ascending doses of FG3622 which will be administered orally. This clinical trial is the first-in-human study in the global development of FG3622 and will be conducted in the UK.

FG3622 is the first of a new generation of novel class systemic antifungal agents active by both oral and intravenous administration to enter the clinic. The mechanism of action, discovered by scientists at F2G, involves the selective inhibition of a fungal enzyme and is completely distinct from any other class of marketed antifungal agent. The compound displays highly potent activity against a wide range of clinically significant moulds including the common pathogen Aspergillus fumigatus which is the leading cause of Invasive Aspergillosis, a serious, debilitating disease associated with very high mortality rates despite current therapy options.

Plenty of work to do yet before this is proven to be useful but this is another example of a growing list of new options becoming available to treat fungal infection.

Monday, 6 July 2009

FDA revise guidelines for rheumatoid arthritis drug Leflunomide

The Food and Drug Administration (FDA) in the United States has issued a safety update for a drug used to treat active rheumatoid arthritis. They now recommend that all patients must be screened for tuberculosis and other pulmonary infections such as aspergillosis prior to taking Leflunomide due to the risk that the drug will increase the chances that these infections will get worse.

Medications with immunosuppressive potential, such as leflunomide, may increase patient susceptibility to opportunistic infections, particularly tuberculosis (including extrapulmonary disease), Pneumocystis jiroveci pneumonia, and aspergillosis.

The FDA notes that leflunomide has not been studied in patients with a positive tuberculin screen result, and the safety of leflunomide in those with latent infection remains unknown. Patients with a positive test result should be treated by standard medical practice before starting leflunomide therapy.

Leflunomide is indicated to reduce signs and symptoms of disease, inhibit structural damage, and improve physical function in patients with active rheumatoid arthritis.

Friday, 3 July 2009

Composting 'scaremongering'??

Industrial scale composting is expanding quickly in the UK and across europe as alternatives to disposing of waste via landfill are explored more vigorously.

Composting is mainly done via open 'windrows' where piles of rotting vegetable matter are left in the open air and turned mechanically at regular intervals. Each turning releases vast clouds of fungals spores, principally Aspergillus fumigatus, an important human pathogen and allergen. Those clouds are rapidly dispersed into the air and diluted such that a safe distance from the composting site should be achievable.

How safe is this practice to both the workers at the composting site and to people living close by? Newspaper articles contend that composting is not yet carried out under completely safe conditions, a story based on a recent paper by Drew et.al. which found that risk analyses at most UK locations where composting is carried out were inadequate.
A rebuttal was issued by pro-composting groups here calling the newspaper stories 'scaremongering' and suggesting that living close to a composting site is no more a risk to health than a walk in the woods:
anyone who walks through a wood especially in the autumn will be exposed to higher levels of these spores than living near a compost site.

I would suggest that it is impossible or impractical to identify individuals who's health is at risk from breathing in fungal spores. Those individuals can include those with poor immune systems & asthmatics. That risk is probably increased if increased number of spores are breathed in therefore until it is possible to warn all people at risk a large margin for safety should be used when setting boundaries for minimising health risks. Risk analyses need to be of a consistently high standard.

Thursday, 25 June 2009

Darwins' fungi

Darwins Fungus (Cyttaria darwinii)
Charles Darwin was born two hundred years ago this year (1809). His contributions to how we understand the natural world were many and varied, culminating in the publication of his book 'On the Origin of Species by Means of Natural Selection' published in 1859.

Darwin was an avid collector and contributed many thousands of species to the British Museum, perhaps most famously during his voyages to the Galapagos Islands. Some of these specimens show the multitude of small differences that Darwin hypothesised constituted adaptions to the local environments of particular islands within the archipelago, caused by natural selection - the driving force of evolution.

Some of the specimens Darwin collected were fungi (mainly fruiting bodies which at that time were thoughtby many to be simple plants) and these are now stored at the Royal Botanic Gardens at Kew, London, UK along with a vast collection of 1.2 million species of fungi including every species of Aspergillus.

This massively important collection, originating 20 years after Darwin published his most famous book, is one of the worlds most complete collections of fungi and forms a resource available to all scientists around the world.

Friday, 19 June 2009

Taxanomic advances lead to better diagnosis & treatment

Invasive aspergillosis is by far most commonly caused by Aspergillus fumigatus. This is an infection that is notoriously difficult to diagnose and it is important to get the diagnosis right as quickly as possible.

Modern techniques to precisely identify different species and strains have started to reveal that different isolates from what was previously thought to be a single species can actually belong to a different groups within that species definition.

What we thought was one fungal species seems to be several different 'species'. To some extent this conclusion might be academic - the differences can seem quite small. This begs the question Are these differences important?

Aspergillus fumigatus is one of the species that have been shown to actually be several slightly different 'subspecies' so it should be possible to look for clinical differences between those subspecies.

A recent paper does precisely that - it looks at a series of 36 isolates (taken from infected patients) that were formerly identified as A. fumigatus and found that they were in fact a group of fungi now named Aspergillus subsection fumigati subgenus fumigati. 4 of the isolates were identified as Neosartorya udagawae (NB Neosartorya is simply the name for the sexual state of Aspergillus).
Furthermore the research paper shows that infections by N. udagawae behaved quite differently to A. fumigatus. The infections were much longer lasting - 35 weeks compared with 5 weeks for A. fumigatus and tended to need a higher dose of antifungal medication.

We thus have an example of how having a much more refined method of identifying the infecting Aspergillus strain could help make the treatment of that infection more effective, improving medical care to the patient.

Friday, 12 June 2009

Detection of hidden moulds

Moulds are notoriously difficult to find. They love damp, dark places, shunning the cleansing effects of sunlight in particular. All they need to grow is moisture and an adequate food source, and these can be found in the most unlikely of places under flooring, in wall cavities and behind cupboards for example.

Detection of moulds when they are growing in inaccessible areas is often impossible without resorting to expensive damage to a property - if none is found then there are hefty repair bills to be paid not to mention the time it takes to carry out the work in the first place.

There has long been a need for a quick, cheap and reliable method for the detection of mould growth in buildings and the solution might have been found at last. It has long been known that moulds emit vapours as they grow, known as volatile organic compounds (VOC).
A recent paper by Moularat et.al. attempts to establish the characteristic pattern of VOC's emitted by moulds growing on building materials. They measured the VOC's being emitted by uncontaminated building materials and compared them with those emitted by materials infested with moulds.

Despite the finding that VOC's emitted by moulds accounted for only 1% of all the VOC's emitted by contaminated building materials, they were able to find a characteristic fingerprint of VOC for moulds growing in buildings and successfully validated it by provings the usefullness of their findings in 11 test buildings. All that was needed to carry out the analysis was a sample of air from within the building.

This study was restricted to the use of 3 species: Aspergillus niger, A. versicolor, Penicillium brevicompactum and relatively few building materials so needs to be expanded but clearly suggests a way forward in this most difficult area of envoronmental health.

Friday, 5 June 2009

Success in the Treatment of Fungal Infection of Transplant Patients

Patients who have received a new organ are usually partially immunocompromised in order to prevent rejection of the organ. This unfortunately leaves them vulnerable to infection with fungal infection being one of the most difficult to treat. Invasive Aspergillosis has a high mortality rate in patients like these and intensive efforts are focussed on improving this situation.

This study uses one of the newest antifungals, voriconazole, and one of the oldest in a new form, inhalable amphotericin. Both are fungicidal and attack different targets so should work together well in combination.

The drugs are used prior to the transplant to attempt to offer prophylactic protection to all patients and are then carried on throughout the transplant process. A total of 53 patients took part.
In the control group 3 patients developed invasive aspergillosis whereas in those patients that reeived voriconazole and inhaled amphotericin there were no cases at all.

There is thus a strong indication that this new combination of drugs offers better protection than the combination of older antifungals used in the control (itraconazole, fluconazole & nystatin).

We cannot say that protection against invasive aspergillosis is complete as this was not a very large trial, but this is certainly another step in learning how best to use the antifungals we have to prevent severe aspergillosis.

Wednesday, 27 May 2009

New classes of fungal phytase genes discovered.

Phytase is produced commercially by microbial fermentation using the fungus Aspergillus niger and other micro-organisms. Phytase is an enzyme used in the animal feed industry that enhances the nutritional value of animal feed and diminishes the phosphate burden on the environment. Phytase hydrolyzes phytic acid, which is the principle storage form of phosphorus in feedstocks of plant origin and can not be digested by gastric farm animals such as pigs and poultry. Phytic acid also forms complexes with proteins, digestive enzymes and minerals, and as such is considered to be an anti-nutritional factor.

The use of phytase eliminates the need to supplement feeds with inorganic sources of essential phosphate. Thus, by releasing bound phosphate in feed ingredients, phytase makes more phosphate available for bone growth, and reduces the amount excreted into the environment.

The discovery of the new fungal genes by TNO, is significant for the commercial production of animal feedstuffs. The increasing availability of fungal genome sequences has allowed a genome mining approach to identify the new gene classes. One class is distantly related to known fungal phytases and the other embraces fungal phytases showing a high homology to bacterial phytases. In collaboration with Dyadic NL, these new phytase gene candidates have been expressed in Chrysosporium lucknowense and were shown to be functionally active.

Wednesday, 20 May 2009

Hazard to world health reduced by Aspergillus

Aspergillus is especially useful for the industrial production of many substances: proteins, enzymes, vitamins and other chemicals as it can be engineered to produce substances in large quantities.

Acrylamide gel being used for DNA sequencingAcrylamide is a highly toxic chemical that is used to form gels useful for many purposes in the laboratory. It was also discovered to be present in fried and baked foods in 2002 and due to its toxicity (carcinogenic and neurotoxic) has been the subject of health campaigns to warn people of the dangers of overheating and overcooking food at high temperatures.

Potato chipsSafe levels of acrylamide are not easy to provide and the wide range of possible sources (i.e. many foods regularly eaten across the world) make this a difficult problem.

It should also be noted that these foods have been in common use in many parts of the world for a long time - this is not a new health risk.

One solution is to treat all at risk foods with an enzyme (acrylamide reducing enzymes) that reduces the amount of acrylamide in those foods. Two such commercial products are emerging; Acrylaway, produced by Novozymes using Aspergillus and PreventAse, an acrylamide-reducing enzyme derived from Aspergillus niger.

Use of these products and others like them should help reduce the risk of acrylamide poisoning for everyone.

Friday, 15 May 2009

Health Risks of Composting

Two recent cases (1, 2) have illustrated that composting in the garden is potentially dangerous for some people.

In a recent article on this blog we discussed several groups that should be cautious when handling compost or any other material that is likely to rot e.g. bark chippings, dead leaves, grass cuttings and more:

  1. Asthmatics, especially severe fungally sensitive asthmatics (SAFS)
  2. Allergic BronchoPulmonary Aspergillosis sufferers (ABPA)
  3. Other people suffering from chronic pulmonary infection by fungi eg Chronic Pulmonary Aspergillosis (CPA)
  4. Immunocompromised people (Transplant patients, recipients of chemotherapy, people taking corticosteroids, people suffering from Chronic Granulomatous Disorder (CGD), Cystic Fibrosis, Diabetics)
These people should avoid all contact with risky materials and for that matter avoid any areas that encourage mould growth - essentially dark, damp places & buildings, even rotten food in a refrigerator.

If a person cannot avoid contact with mould then they should wear an adequate face mask. An ordinary woodworkers dust mask is useless as the spores are so tiny they would not be filtered out. As a minimum specification an N95 facemask is suitable - see facemask guidelines on the Aspergillus Website.

Friday, 8 May 2009

Aspergillosis: A patient's success story

Christine and Brian Lowe launching the National Aspergillosis Centre alongside Dr Chris SteeleBrian Lowe had beaten cancer and MRSA but was still ill. He coughed up copious amounts of phlegm and the normal antibiotics had no effect. His local doctor admitted defeat and referred Brian to the North West Lung Centre (NWLC) at Wythenshawe Hospital, Manchester, UK.
Within the NWLC there are consultants and specialists with several different types of expertise and the facilities to diagnose and treat a wide range of respiratory illness.

Luckily the NWLC also houses the clinic that has now become the National Aspergillosis Centre (NAC) and Brian was quickly diagnosed as suffering from an aspergillus infection of his lungs that followed his cancer treatment (full story).
Rapid diagnosis is essential to improve the outcome for most patients suffering from all types of aspergillosis and the NAC is ideally positioned to achieve those needs alongside the Regional Medical Mycology Laboratories also .

Thankfully Brian recovered well after treatment and was well enough to help launch the National Aspergillosis Centre last week (1st May). Hopefully many more success stories will follow!

Wednesday, 29 April 2009

National Aspergillosis Centre, UK

Dr Chris Steele
The first national centre for the treatment of aspergillosis sufferers will be formally launched at the University Hospital of South Manchester (Wythenshawe Hospital) on Friday May 1st 2009.

The UK National Aspergillosis Centre has been commissioned by the Department of Health, initially to provide long term care for patients with chronic pulmonary aspergillosis. This condition is one of several types caused by the common airborne fungus Aspergillus.

The centre aims to provide comprehensive, excellent care for all patients with aspergillosis and will link specialist consultants, nurses, surgeons, radiologists and researchers with specialised laboratory facilities to reduce fatalities and deliver a better quality of care.

The centre will be opened by TV doctor Chris Steele who said it will not only provide a valuable service for patients but also provide a national focus on a little known but highly debilitating disease.

The National Commissioning Group commission medical services for specific groups of patients with extremely rare conditions or which require unusual or costly treatment and advise ministers on which NHS services are best commissioned nationally rather than locally.

Friday, 17 April 2009

How we tell one Aspergillus species from another

Traditionally Aspergillus species were identified by looking at how they grew in the laboratory, by careful examination of the structure of their fruiting bodies - the conidium and by comparing those features with special reference strains. It is possible to read how these features are recorded in the species section of the Aspergillus Website.
As time has gone by and more an more potential new species are identified these techniques have proved to be inadequate. Some species were shown to be so closely related they were listed as varieties within a group rather than as distinct species - it wasn't possible to tell enough difference between them.

At the same time a slew of new information has become available which helps show us the differences between species in different ways. Principal among these new technologies is DNA sequencing and the new science of genomics. Similarities and differences between the DNA sequences of species can now be routinely examined and that information is used to say whether or not 2 candidate species are distinct, related or virtually the same.

This still isn't the full story and genomics data cannot be taken in isolation from all the other data, some new and some old. The way forward has been strongly suggested to be a polyphasic approach (first suggested many years ago) involving taking into consideration features from all available evidence: morphology; physiology; DNA; protein; ecology; metabolites, and reaching a concensus.

The result is complicated but often very robust: the full concept can be read in this recent paper.

Wednesday, 8 April 2009

Mobile phones as a reservoir for Aspergillus

A recent study in India shows that Aspergillus, amongst others can often be isolated from the mobile phones of professional health workers.
The mobile phone consists of a number of cavities and surfaces that can provide adequate moisture (from sweat) and food (the contents of pockets, human skin cells) for fungal growth. Phones are rarely if ever cleaned adequately so microbes lie largely undisturbed.

Considering that many professionals use mobile phones on and off the wards this may be another route through which Aspergillus and other infective microbes (e.g. MRSA) can get to the patient.

Outbreaks of aspergillosis occur in wards despite all the care taken to prevent the spores of the fungus gaining entry. Many routes have been considered (Barnes 2000) but maybe this relatively new source requires attention too.

Friday, 3 April 2009

A quick new test for Aspergillus infections in patients

A rapid new test for Aspergillus fumigatus fungal infections has been described at the Society for General Microbiology meeting in Harrogate on April 2nd. Fungal infections by Aspergillus species are a major cause of death in patients whose immune systems are suppressed or damaged - for instance transplant patients or those undergoing chemotherapy.

These groups of patients are susceptible to an invasive form of aspergillus infection with a high fatality rate. Invasive aspergillosis is currently difficult to diagnose and tests are lengthy and expensive. Current tests are not always specific and false positives are not infrequent.

Dr Christopher Thornton and colleagues, of the University of Exeter, UK has developed a test for invasive aspergillosis using a technology similar to that in home pregnancy tests. The test uses a monoclonal antibody which binds to a glycoprotein antigen secreted specifically by Aspergillus species. It does not apparently give a cross reaction with any other clinically important fungi and takes 15 minutes to perform, making it quicker and less costly than conventional laboratory-based tests. Being user friendly it may be useful at the point of care as a result of its speediness.
The test is currently being developed with a multinational clinical diagnostics company to develop a commercial version of the test.

Thursday, 26 March 2009

Awareness of Aspergillus contamination of marijuana grows

An example of moldy conditions used for some marijuana cultivation
We reported in this blog around a year ago that one of the hazards of smoking marijuana was the possibility that the smoker would also inhale spores of the Aspergillus fungus (among others). Just like any other plant material after harvest and before it is fully dried out marijuana is an ideal food for Aspergillus - the fungus grows quickly and will sporulate once the food supply starts to decline. Those spores are extremely tiny and will penetrate the deepest parts of the smokers lungs.

Health effects of this can start with the development of allergies, increase asthma symptoms, cause severe asthma by fungi growing within the lungs, allergic bronchopulmonary aspergillosis (ABPA) and so on. All of these can happen to people who have completely healthy immune systems - these are not invasive infections but are chronic debilitating illnesses with no cure yet devised. People who do have a poor immune system i.e. transplant recipients, people being treated for some types of cancer, people on high doses of steroids are much more at risk of an invasive infection, so inhaling spores is a very bad idea!

Marijuana is particularly prone to fungal growth as it is often grown and prepared by amateurs who have limited idea of the dangers Aspergillus can bring or how to avoid them. Storage is also an issue - if it becomes damp the fungus can grow all over again. Up until now there has been no known effort to establish the levels of Aspergillus in marijuana.

News this week is that a laboratory has been set up on California, USA to advise users of this material on the levels of contamination in samples of the drug that the users bring in. Legality aside this can only be a good thing for the marijuana users of that area, perhaps partially akin to the handing out of free sterile syringe needles to IV herione accicts?

Thursday, 19 March 2009

The solution to toxic Aspergillus is... more Aspergillus!

Growth of Aspergillus on crops is common when drought conditions predominate. This is possibly because lack of water weakens plants and make them more vulnerable to growth of the fungus.
This causes a major problems when the Aspergillus species growing on the crop starts producing toxins - something the fungus commonly does when it is stressed by - for example - low levels of moisture.
Fungal toxin levels allowed in crops such as peanuts and corn are strictly controlled by the authorities so the crops are tested rigorously prior to sale. Crops containing higher levels of toxin are worth less than crops with low levels of toxin - toxins cost the farmer money and reduce the amount of crops available for human consumption in the US. NB poorer countries have to buy in some of the cheapest crops they can find and they are often those with higher levels of toxin - thus introducing higher levels of toxins into their food system - this problem effects everyone around the world.
What to do? A simple solution has been investigated and found success - spray the crops and soil with a strain of Aspergillus that doesn't produce toxins! Crucially a strain of Aspergillus that grows more quickly than toxin-producing strains has been isolated and sprayed onto corn crops. At harvest time on sprayed crops no toxin has been detected compared with levels detected in neighbouring fields that exceeded admissable levels - a resounding success.

No chemicals, relatively cheap to produce and sustainable.

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