Tuesday, 23 February 2010

A step forward for aspergillus PCR diagnostics

Diagnosis of an invasive aspergillosis infection can be very difficult, partly because some of the techniques used can take up to 2 weeks to carry out (culture) and others simply don't work for some forms of infection while they do in others (Reference).
Diagnosis of invasive aspergillosis has to be as quick as possible as in some cases the rate of infection is very rapid. PCR (Polymerase Chain Reaction) is a technique which allows specific DNA sequences to be detected and analysed very quickly - in a matter of hours. It can detect extremely small amounts of material and can be very specific, detecting one molecule in many billion, so for these reasons it has great potential to detect infecting organisms using only blood samples taken from the patient. Unsurprisingly it is being developed for use in aspergillosis and though there are many challenges to its success substantial progress has been made.



One of the major blocks to advance in this and any other similar technology is the lack of agreed standard protocols for everyone to use. There are many groups around the world working on this technology and initially each will have their own best method, but such is the sensitivity of PCR each method may well give different results. For further progress to be made everyone needs to use one agreed set of protocols.
This latest paper announces that this process has been started. There is now an agreed standard (optimised) method for the extraction of DNA from Aspergillus from a clinical sample of whole blood - the crucial first step in the PCR process.

Results from any lab that uses this protocol will now be directly comparable with each other, so if a lab comes up with a modification of the next step (e.g. primer preparation, thermal cycling) that improves the result (e.g. better sensitivity, fewer false positives/false negatives) then all will be able to repeat the modification knowing that they carried out the initial steps in exactly the same way, and will thus be able to directly compare the results. If it is an improvement then it will be adapted much more quickly than before.

As a direct result of this work the development of PCR for use in the diagnosis of aspergillosis will be speeded up.

Thursday, 18 February 2010

50 million year old Aspergillus

The first example of fossilised Aspergillus was found in Dominican amber in 1988 and was tentatively identified as Aspergillus janus which is still found growing today. Dominican amber has been dated at 15-20 million years old - the Miocene period of the fossil record.

Amber is natures 'time capsule' originating as sticky resin exuded by ancient trees on which insects and other debris became stuck. The resin would continue to run out of the tree and the trapped insects could become completely enclosed, sealing them from the air and thus preventing decomposition - the specimens are frequently perfectly preserved.
Over time the trees died and eventually the resins hardened into amber. In several areas of the world amber is readily available and is dug up for a variety of purposes including making jewellery, but occasionally especially interesting specimens are found which carry huge scientific interest.

Aspergillus has more recently been found growing on an insect trapped in a piece of fossilised Baltic amber. Baltic amber is considerably older (35-50 million years old) than Dominican amber so this is the oldest example of fossilised Aspergillus found to date.
The authors of the paper name this fungus Aspergillus collembolorum, presumably because it did not closely resemble a modern species. It is suggested that this fungus was parasitising this insect rather than using it as food once the insect had died as it is the only identifiable fungus on the insect - other examples in amber clearly show several species of fungus attacking individual insects, much as they would today if the insect had already died.

35-50 million years ago puts this specimen in the Eocene period ('New dawn') of the fossil record, a time when the first mammals were emerging and the world experienced a period of high temperatures and warm oceans. Several continents that are today quite separate were joined at the beginning of this period - Australia and Antarctica were linked, Europe, Greenland and North America where just starting to drift apart.

Saturday, 6 February 2010

Advances Against Aspergillosis - Rome 2010

The fourth Advances Against Aspergillosis meeting is drawing to a close in Rome and has been the most successful yet, building on the rapid progress this meeting has made since 2004. The numbers attending has risen from 200 in 2004 to well over 500 at this meeting with nearly 200 posters presented.

The purpose of the meeting this year is as always to act as a forum for interaction between researchers and clinicians in order to improve communication between the different type of workers and therefore to improve efforts to advance diagnosis and treatment of these illnesses.

The Aspergillus Website are assisting this process by hosting all the abstracts from the meeting and as many of the slide presentations we can get permission to use - in this way we hope many more people will be able to understand the breadth and depth of the subjects covered.

In addition this year there was a meeting for patients in which patients participated from many countries alongside notable experts in several fields. This meeting was a great success, the talks (written and presented so that they can be understood by 'ordinary' people rather than scientists and medics) have been recorded and will be available online in a few weeks.

Friday, 5 February 2010

Aspergillosis Meeting for Patients - Rome

The Fungal Research Trust sponsored a meeting prior to the Advances Against Aspergillosis meeting on 3rd February 2010, which was devoted to translating the latest medical and scientific information in this field into presentations that could be given to patients to enhance their understanding of their illness. There were question & answer sessions between each talk so that patients could get answers direct from the speaker, supplemented by questions submitted prior to the conference from interested patients who could not travel to Rome.

At the end of the day there was excellent food & drink to enable informal chats between all participants which propogated many useful discussions between patients, doctors and nurses.

All talks and Q & A sessions were video recorded and will be made available in a few weeks on the Aspergillus website. Available sooner will be written summaries of each talk.

Monday, 1 February 2010

New antifungal leaps its lastest hurdle

Basel, Switzerland, January 29, 2010 - Basilea Pharmaceutica Ltd. (SIX:BSLN) announces that based on a futility analysis of the isavuconazole phase III trial for the treatment of invasive Aspergillus infections, the Independent Data Safety Monitoring Board (IDSMB) has recommended the continuation of the study.
Isavuconazole is the latest in the long line of 'azole'-type antifungals to be developed. Of the earlier azoles some have difficulty in absorption for some people (itraconazole - Sporanox) or have quite severe side effects such as light sensitivity (voriconazole - Vfend). This latest drug has test results that indicate that it is superior in these respects to its predecessors, but this is based on laboratory and trials in quite small number of people.

This announcement does not mean that any of the prospective advantages of this drug have been proved or even whether or not it is better than the drug it is being compared with (voriconazole) - that is the end point of this trial and this is a 'mid-point' assessment which checks to overall results without knowing who is taking which drug. This is simply a statement that the drug has not had any major problems or unexpected issues during the first part of the trial and that the trial can continue. If some patients had been found who had major health problems the trial would have been stopped to prevent any further cases.

The trial will now go ahead with recruitment and treatment with the aim of completing as soon as possible in the hope of providing another useful antifungal to use in the battle against fungal infections.

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