BACTERIA that can resist nearly all antibiotics have been found in Antarctic seawater.
Björn
Olsen of Uppsala University in Sweden and colleagues took seawater
samples between 10 and 300 metres away from Chile's Antarctic research
stations, Bernardo O'Higgins, Arturo Prat and Fildes Bay. A quarter of
the samples of Escherichia coli bacteria carried genes that made an enzyme called ESBL, which can destroy penicillin, cephalosporins and related antibiotics (Applied and Environmental Microbiology, DOI: 10.1128/AEM.07320-11).
Bacteria
with these genes can be even more dangerous than the better known
superbug MRSA. That's because the genes sit on a mobile chunk of DNA
that can be acquired by many species of bacteria, increasing the
incidence of drug-resistant infections such as the E. coli outbreak last year in Germany.
The type of ESBL they found, called CTX-M, is common
in bacteria in people, and the Uppsala study found that concentrations
of resistant bacteria were higher close to the sewage outfalls from the
stations. Some Antarctic stations started shipping out human faeces for
incineration after gut bacteria were found nearby. Chile's research
stations have virtually no sewage treatment in place, says Olsen.
Recent work shows the bacteria may hang on to the genes for CTX-M even when no longer exposed to antibiotics,
suggesting that superbugs can survive in the wild, with animals acting
as a reservoir. Penguins near the Chilean stations have been checked
and are free of ESBL, though Olsen is now looking at the area's gulls
as he has found ESBL-producing bugs in gulls in France.
"If these genes are in Antarctica, it's an indication of how far this [problem] has gone," he says.
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