When an exceptionally virulent outbreak of illness from
E. coli bacteria infected more than 2300 across Europe, killing at least 27 (mostly in Germany), health officials were understandably concerned. But when the World Health Organization (WHO) announced that this new and villainous strain of E. coli had never been seen before by scientists, concern grew to flat out alarm.
According to the Beijing Genomic Institute in China, this new E. coli strain is extremely dangerous. After analyzing the bacterium it was found that this new strain of E. coli has a 93% DNA sequence similarity with an E. coli strain that was previously isolated in the Central African Republic. People infected with this African strain suffered from serious diarrhea (sometimes fatal). What is alarming about the latest European strain of E. coli, however, is that it also has specific sequences similar to the strains involved in hemorrhagic colitis and hemolytic uremic syndrome (a condition which causes severe kidney damage).
It appears the E.coli under investigation may have acquired these genes through horizontal gene transfer. Basically what this means is that one E. coli strain acquired toxins from another E. coli strain and the result was an extremely nasty new bacteria. It is producing two highly infectious toxins that lead to
bloody diarrhea and sometimes fatal kidney damage.
Identifying the new E.Coli strain.How did the researchers realize this was a new strain of E. coli? Genetic fingerprinting is the process used to analyze and identify an organism’s DNA makeup. It employs a process known as electrophoresis whereby an organism’s DNA is cut into sections and put into a slab of agar gel. Both the gel and the DNA are then covered with a buffered solution that conducts electricity. When exposed to an electrical charge, the DNA starts to travel down the agar track at different speeds and lead to the formation of bands. These bands can be compared to other samples of E. coli for identification. If that particular fingerprint isn’t in the database, then you know you’re dealing with an organism never seen before. This was the case with the new strain.
Life-threatening complications.Kidney failure has been one of the worst results of the E. coli outbreak. This is often a life-threatening complication of most E. coli outbreaks, but usually only a mortal threat to small children or those with
weakened immune systems. But in this current outbreak, young and middle-aged adults, two thirds of them women, make up a high percentage of those affected. So far Germany has reported 470 kidney failure cases from their 1500 infections.
Identifying the source.One of the most troubling aspects of the situation is that scientists still are not certain where the outbreak began, nor do they know what food is carrying the bacteria. It was first believed to be Spanish cucumbers but that seems to have been a mistake. A very costly mistake for Spanish farmers, it turns out, as it has been reported that hundreds of millions of dollars have been lost. As a matter of fact, produce farmers all over Europe are starting to feel the strain as consumers have stopped buying fruits and vegetables because they’re afraid
anything could be the carrier.
Though researchers are hard at work tracing the E.coli back to its source, a lack of a comprehensive pathogen database could very well mean the original culprit is never found. This is extremely unfortunate as the outbreak could continue for months on end. (Editors update: Testing has confirmed that sprouts were the source of the E. coli outbreak.)
