MicrobiologyBytes

With the fall in H1N1 “swine flu” influenza cases recently, it has become fashionable for the media to run “What was all the fuss about” stories on the same page as “OMG, it’s going to be bad” stories. The problem with influenza is that it is one of the most unpredictable of all viruses, and while an upsurge in the number of cases can be expected as the winter flu season gets going in the northern hemisphere, the real concern is that this new pandemic virus might “turn nasty” in the second wave, just as in 1918 a much more pathogenic variant of that virus followed the relatively benign first wave of cases.

There are two ways in which this could happen. The first is that the present virus acquires spontaneous mutations which make it more pathogenic. The other possibility is that the virus recombines with a highly pathogenic influenza virus though the process known as reassortment – swapping of genes when two different strains infect the same cell. And there’s a good candidate for that out there – the highly pathogenic H5N1 avian influenza virus. Unlike H1N1, H5N1 has a hard time infecting humans, so it’s unlikely that these viruses would meet. But if they did…

The good news comes from Egypt, where H5N1 is relatively common, and a (worrying) case of H5N1/H1N1 co-infection was recently reported. The Ministry of Health has now discounted the rumour of a co-infection with the two viruses. In addition, a University of Maryland/NIH study suggests that co-infections of H1N1 with seasonal flu viruses do not produce chimeric or reassortant viruses. The H1N1 strain seems to outcompete seasonal viruses, possibly demonstrating this pandemic strain is not under biological pressure and is perhaps more efficiently communicable. Certainly, the past pattern seems to suggest that H1N1 pandemic seem to suppress outbreaks of other strains for some time.

A phase I clinical trial conducted by scientists from the University of Leicester tested 100 healthy volunteers with an H1N1 vaccine to see how their immune system responded. Trial leader Dr Iain Stephenson found 80 per cent of the volunteers showed a “strong, potentially protective” response after one dose, with more than 90 per cent showing the same response after two doses. The results suggest that one vaccine dose may be sufficient to protect against A(H1N1) swine flu, rather than two. Larger trials are now under way around the world involving up to more than 6,000 adults and children.

Reasons to be cheeful.

Related:

• H5N1 and 1918 pandemic influenza virus infection and the lungs
• Spotting pandemic influenza viruses
• How influenza pandemics get started
• The Pathogenicity of Pandemic Influenza Viruses
• The Great Flu – a free online game

You may remember that the University of Leicester was named University of the Year 2008 in the Times Higher Education Awards, and that we’re all happy bunnies. The good news is that from 2010, you have not one but TWO choices to study microbiology at Leicester:

• Microbiology or:
• Medical Microbiology

Can you afford not to find out more?

Joseph Morley of the University of Leicester has been awarded the Society for General Microbiology Undergraduate Microbiology Prize 2008 – an award for best performance in second year microbiology modules. This prize aims to encourage excellence in the study of microbiology by undergraduate students, and to promote scholarship in and awareness of microbiology in universities.

The Society for General Microbiology (SGM) is the largest microbiological society in Europe. It has over 5000 members of whom 75% are resident in the UK with the rest in more than 60 countries worldwide. Joseph, who is currently working on his final year research project on marine cyanophages, was awarded a cheque for £150, a certificate and one year’s free undergraduate membership of the SGM. Joseph says he is delighted to be awarded this prestigious national prize.

According to The Guardian:

Leicester students certainly appear to be happy bunnies: it came joint top for teaching quality and overall satisfaction in the National Student Survey two years in a row and the drop-out rate is notably low. The appeal might lie in the friendly and compact campus – a 10-minute walk from one end to the other, providing you don’t get sidetracked by any of the on-campus facilities. Victoria Park next door is a convenient and popular place to relax when the weather is good. As well as that, Leicester puts up a consistently strong academic performance across all its subject areas. It’s understandably proud of its most famous research achievement: the development of DNA genetic fingerprinting. Add on Leicester, a lively, multicultural city with great facilities and transport links, and it’s no wonder everyone is so pleased to be there.

The latest version of the Good University Guide puts the University of Leicester in 12th place, up from 20th last year.
More importantly ;-) Biological Sciences came 10th out of 87 in the subject rankings, our highest ever position in the Guide.

It is commonly thought that the Mycobacterium tuberculosis cells found in the saliva, phlegm and mucus of people infected with tuberculosis are active and growing. Indeed, the therapy of TB infections relies on this view. New research just published by my colleague Mike Barer, who teaches on the microbiology degree here at the University of Leicester, and his collaborators in London, shows that a significant proportion of the tubercle bacilli in sputum – those with distinctive lipid bodies in their cytoplasm – do not conform to this view. These “fat and lazy” bacteria do not replicate, and show greater tolerance to antibiotics than their more active siblings (Cytological and Transcript Analyses Reveal Fat and Lazy Persister-Like Bacilli in Tuberculous Sputum PLoS Med 5(4): e75).

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Every year, nearly nine million people develop tuberculosis and about two million people die from the disease. Diagnostic tests for tuberculosis include chest X-rays, the tuberculin skin test, and sputum analysis. For the last of these tests, a sample of sputum (mucus and other matter brought up from the lungs by coughing) is collected and examined under the microscope for M. tuberculosis using special stains and also by trying to grow bacteria from the sample. Tuberculosis can be cured by taking several different antibiotics for several months. It is very important that this treatment is completed to ensure that all the tuberculosis bacteria in the body are killed and to prevent the emergence of drug-resistant bacteria. Very little is known about the efficiency with which M. tuberculosis spreads from one person to another.

The researchers collected sputum samples from patients with tuberculosis in the UK and in The Gambia before they had received any treatment. They looked for the presence of acid-fast bacilli containing “lipid bodies”, small structures within the cells containing a fat called triacylglycerol. M. tuberculosis accumulates triacylglycerol when it is exposed to stresses present during infection (for example, reduced oxygen, hypoxia) and it was thought that that the presence of this fat may help the bacteria survive during transmission and establish a new infection. M. tuberculosis grown in the laboratory under hypoxic conditions, which induces the bacteria to enter an antibiotic-tolerant condition called a “nonreplicating persistent” (NRP) state, accumulated lipid bodies. The researchers compared the pattern of mRNAs made by actively growing cultures of M. tuberculosis, M. tuberculosis maintained in the NRP state, and by acid-fast bacilli from sputum samples. The transcriptome of the sputum sample revealed production of many proteins made in the NRP state. Finally, they showed that the time needed to grow M. tuberculosis from sputum samples increased as the proportion of lipid body–positive acid-fast bacilli in the sputum increased.

The characteristics of this population of bacteria might help them survive the adverse conditions that M. tuberculosis encounters during transmission between people and might partly explain why complete clearance of M. tuberculosis requires extended treatment with antibiotics. To establish the clinical significance of these findings, future studies will need to examine whether antibiotic treatment affects the frequency of lipid–positive bacteria in sputum and whether there is any relationship between this measurement and infectiousness, or clinical response to treatment. Professor Mike Barer says:

These surprising findings have opened the door for us to develop new ways to stop TB from spreading and to treat it more effectively. We hope that our new ability to monitor these sleepy and resistant bacteria in sputum will enable us to treat the disease more quickly.

Related:

• The Mummy
• Tuberculosis – is the white plague winning?
• Resuscitating Mycobacterium tuberculosis
• Tuberculosis virulence gene inhibits apoptosis of infected host cells
• Progress towards a new tuberculosis vaccine