February 19, 2008

scientists react to paper on antibiotic resistant E. coli as published in the Lancet Infectious Diseases

The paper, from a team of Canadian scientists, looked at antibiotic resistance in certain strains of E. coli, and revealed that the problem of resistance is spreading beyond hospitals and into the community.

Dr Andrew Berrington, Consultant Microbiologist, Sunderland Royal Hospital, said:

“This is a battle we should monitor better, but not one we can win.

“The article is a timely reminder of the problem of extended-spectrum beta lactamases in E. coli, Klebsiella and other related organisms, and it does seem to be true that what was previously regarded as a hospital problem is now being seen in the community as well. These bacteria are not, as far as is known, excessively virulent, but they are becoming more resistant to antibiotics and therefore harder to treat.

“We are faced, with patients in the community (who may or may not have been in hospital) with infections caused by bacteria that are resistant to most or all of the antibiotics that would have been used traditionally. The challenge is what to do then: do we use less effective agents, do we offer intravenous therapy at home with expensive, broad-spectrum antibiotics that carry their own problems, or do we accept that some minor infections should be treated without antibiotics? In hospital there are very few ‘untreatable’ infections because of the additional options available (though this might change), but effective treatment might be delayed while waiting for laboratory results, and is likely to require drugs that we would otherwise have preferred not to use because of their expense, or their higher risks of promoting such familiar problems as MRSA and C. difficile.

“It is also true that laboratories have been slow to respond. Traditionally urine microbiology has been a laboratory backwater, in which the significance of the bacteria isolated was often unclear (because urine samples are hard to take without contaminating them), in which bacteria were often not fully identified (because it was irrelevant whether a urine infection was caused by Escherichia coli or Klebsiella pneumoniae provided it could be treated easily), and in which sensitivity testing was poorly standardised. This is changing, partly because of automation, but the current tariff doesn’t exactly encourage innovation or bespoke testing, and many laboratories’ routine practices would still fail to detect ESBL-producing organisms. There is an argument that all ‘coliform’ bacteria that seem to be causing infections should be identified to species level, and that they should all be tested for the presence of extended spectrum beta-lactamases, but this would cost money. Moreover it would inform epidemiological studies and help ensure that individual patients were treated properly, but it is unlikely to halt the spread of ESBL-producing bacteria because this is being driven by antibiotic use more generally, and because these are bacteria that can live harmlessly in the gut in enormous numbers, and because we don’t have the facilities to isolate them from other patients.”