Earlier this week on Monday came reports from Germany that 6 people who consumed raw vegetables were killed and hundreds rendered ill . Initial investigations pointed towards consumptions of raw cucumber, lettuce and tomatoes. The fatalities were attributed to hemolytic-uremic syndrome, or HUS, from E. Coli. Since then, more people have died and the infection has spread to different parts of Europe . Cases have been reported from Sweden, Austria, Denmark, France, Netherlands, Norway, Spain, Switzerland and the United Kingdom. At the initial stages opinions about whether the strain was new differed between scientists. Scientists at the Beijing Genomic Institute called it a new "super-toxic" E. coli strain whilst the U.S. Centers for Disease Control and Prevention said that it was a known strain.
Today the WHO announced that the German strain was novel and that it had never been isolated before in humans. With the death toll having risen to 18, whilst over 1000 people remain ill, German scientists are desperately trying to sequence the bacterial genome. The news from WHO also indicates that the strain had never been found in any animals which signifies that it could have come directly from the environment into humans. The scientific community is awaiting with bated breath for the results from sequencing of the genome of this deadly strain of bacteria . The sequence of this strain of E.coli might explain the differential infection pattern observed- the bacteria is mostly infecting adults, and generally women.
Emergence of super-bugs are of grave concern. In April, the Lancet reported bacteria carrying a gene that confers resistance to a major class of antibiotics identified in samples of drinking water and sewage effluents from New Delhi. This gene blaNDM-1 encodes the enzyme New Delhi metallo-β-lactamase 1 (NDM-1). Bacteria can pass genes easily through plasmids. The enzyme blocks the activity of a range of antibiotics. NDM-1-positive strains of both species have previously been found in hospitals in India and Pakistan and have already been seen in the United Kingdom and elsewhere in patients, some of whom had previously been in hospitals in the Indian subcontinent.
The problem with virulent bacteria as with most infectious agents is that it is hard to be confined. As of now, the source of the German E.coli strain has not been pin pointed. With bacterial outbreaks such as this there is nothing called a ‘local problem’ but a ‘global problem’ and combating it requires a concerted effort where the blame game doesn’t help much.
References:
German E. coli outbreak caused by previously unknown strain (Nature, June 2nd, 2011)
World health officials scramble to stem deadly E. coli outbreak (CNN, June 2nd, 2011)
EHEC outbreak: Rare strain of E. coli unknown in previous outbreaks (WHO, June 2nd, 2011)
Kumarasamy KK, Toleman MA, Walsh TR, Bagaria J, Butt F, Balakrishnan R, Chaudhary U, Doumith M, Giske CG, Irfan S, Krishnan P, Kumar AV, Maharjan S, Mushtaq S, Noorie T, Paterson DL, Pearson A, Perry C, Pike R, Rao B, Ray U, Sarma JB, Sharma M, Sheridan E, Thirunarayan MA, Turton J, Upadhyay S, Warner M, Welfare W, Livermore DM, & Woodford N (2010). Emergence of a new antibiotic resistance mechanism in India, Pakistan, and the UK: a molecular, biological, and epidemiological study. The Lancet infectious diseases, 10 (9), 597-602 PMID: 20705517
Poirel L, Hombrouck-Alet C, Freneaux C, Bernabeu S, & Nordmann P (2010). Global spread of New Delhi metallo-β-lactamase 1. The Lancet infectious diseases, 10 (12) PMID: 21109172
Prevention is better than cure, but can't say for sure how to prevent drug-resistant bacteria. I wonder what would be the best way to prevent them - washing vegetables thoroughly might remove a few bugs yet may not be that effective, so do we just stop eating raw vegetables? Things are getting serious and scary!
ReplyDeleteThanks for your comment and for your interest in our blog.
ReplyDeleteHow do we prevent drug emergence of drug resistant bacteria in the first place?
Evidence indicates that indiscriminate use of antibiotics in humans as well as in livestock could contribute to antibiotic resistance.
How do we prevent ourselves from getting infected?
E.coli is a bacteria that is found in the gut of humans. It is normally harmless. But few strains such as the German one are harmful.
Infection occurs through water & contaminated food.
The WHO site forwards advice from the Robert Koch Institute in Germany which is to avoid eating tomatoes, cucumbers and lettuces. Additionally, to adopt the usual hygiene measures in handling fruit and vegetables.
Regular hand washing, before preparation of food or eating. Washing hands after toilet contact, is highly recommended in the WHO webiste particularly for people who care for small children or are immunocompromised specifically since the bacterium can be passed from person to person, as well as through food, water and direct contact with animals.
With recent news in the media that bean sprouts could be the culprits, there is one other vegetable in the list where precautions should be taken. Most bacteria if not all are killed at high temperatures, so washing and cooking the vegetables might be a welcome measure.