New Strains of E. coli

Scientific American (August 2011) has provided us with some facts regarding E. coli and the new strains:

Antibiotics can worsen an E. coli infection. Giving antibiotics, including Cipro, can kill a patient who has been sickened by any strain of Shiga toxin E. coli. The reason: when the bacteria die, they release the toxin in massive amounts. Fortunately, carbapenem antibiotics, seems to not trigger such a major toxin release, but these drugs are usually only prescribed in special circumstances.

E. coli O104:H4 is resistant to at least 14 antibiotics. Nobody knows why, because many of 14 are not typically used to treat E. coli infections. This means that either this bacteria, or one it has swapped genes with, must have developed in an environment that was full of antibiotics—most likely a hospital or a farm.

The original E. coli, O157:H7, is no longer a threat (in the USA), due to the government requiring food producers to test and report any outbreaks. However reporting outbreaks of the new, more dangerous strains is not yet mandatory!

New, Killer E. coli Strain O104:H4

The German outbreak of E. coli last week killed at least 26 people and made news headlines around the planet – it was the deadliest E.coli outbreak ever recorded, as well as many hundreds suffering kidney failure. E. coli strains have and will continue to cause deaths, but this particular strain is more worrying. The following quotes are from the website of the AAAS Science magazine, a no sensationalism zone, and the Wall Street Journal:

…a never-before-seen hybrid, combining the worst of several bacterial strains. …one gene fragment appears to have come from another food-borne pathogen, Salmonella enterica, while other genes are highly homologous to those found in other, phylogenetically distinct E. coli strains, including a strain called O25:H4-ST131. [Science Mag]

The 2001 strain caused fewer than five identified cases world-wide, and scientists never did identify its natural reservoir—where a new strain of the E. coli bug can originate, such as in cattle. But the genetic analysis showed that as the 2001 bug likely swapped genetic material with other bacterial strains, some big changes occurred.

The 2011 version turns out to be resistant to eight classes of antibiotics, including penicillin, streptomycin and sulfonamide. The likely reason is that rapid evolution “resulted in the gain of more genes during the last 10 years” that conferred immunity against many more antibiotics, according to BGI. [WSJ]

The new bug is more deadly, more contagious, and more resistant. In the Weekend Australian, Michael Osterholm was quoted: I’ve never seen this array of virulence and antibiotic resistance. It’s a unique combination. This is the ongoing trend with many bacterial infections, meaning things will only get worse.