June 03, 2011
The E. coli currently making its way through Europe is “a new strain of bacteria that is highly infectious and toxic” according to scientists at the Beijing Genomics Institute who have sequenced the microbe’s genome.
There are a number of concerns about the mysterious bug, dubbed EHEC O104:H4, which has sickened approximately 2,000 people in 12 European countries, with most cases appearing in northern Germany. Most worrying is the high rate of associated serious complications leading to kidney failure. As of today, the Robert Koch Institute in Germany has reported 520 cases of potentially life-threatening haemolytic uraemic syndrome (HUS) resulting from the new E. coli strain. Thus far, 18 people have died in the outbreak.
In recent days, reports over the bacteria’s resistance to antibiotics have also prompted fears of a raging, untreatable superbug. But it’s important to note that antibiotics are not a typical treatment for GI infections caused by E. coli. The New York Times reports that certain antibiotic treatments may actually do more harm than good, wiping out commensal bacteria in the gut and also putting the patient at higher risk for kidney failure.
A commentary from Nature describes in more detail why antibiotics might actually be counterproductive in treating the illness, but also why the particular virulence of this strain is prompting German health officials to look at how certain classes of drugs may be indicated in special cases. They note:
The German Association of Infection Biology (DGI) released a statement on the use of antibiotics this morning. It states that the use of certain antibiotics associated with enhanced toxin secretion (including fluoroquinolones and aminoglycosides) are still not recommended for EHEC infections. But it advises that the antibiotic carbapenem may be used in patients showing neurological complications and secondary infections The DGI statement also states that targeted reduction of intestinal bacteria with the antibiotic rifaximin is recommended in exceptional cases of EHEC persistence.
The effectiveness of this strategy of course depends on the strain’s susceptibility to carbapenems a powerful class of antibiotics. It’s also worth mentioning here that although E. coli is most commonly known as a cause of food-borne illness, it is also the cause of 90% of urinary tract infections (UTIs). For UTIs, antibiotics are standard treatment and antibiotic resistance is a serious and growing problem. ResistanceMap shows the trends in E. coli resistance to first-line antibiotic treatments in the United States, but the issue prevails worldwide.
In containing the current outbreak, there are still many questions about the epidemiology of its origin, spread, and the development of resistance to common antibiotics. This particularly virulent E. coli strain is a serious reminder of the existing gaps in food safety systems in the U.S., the outbreak is prompting some sharp critiques of the regulatory structure for taking action against foodborne epidemics, particularly for emerging strains.
Image credit: Flickr: elmofromok
