Strains of Escherichia coli bacteria that cause food poisoning have been shown to have marked differences in the numbers of genes they carry compared to laboratory strains of E. coli, show studies.
Some of these genes may enable them to survive stresses such as those caused by modern food processing techniques or exploit food sources that laboratory E. coli strains cannot use.
Dr Karin Heurlier and colleagues at the Universities of Nottingham and Birmingham in conjunction with Biolog Inc of California USA, used powerful high throughput analytical tools (phenotype microarrays) that enabled them to compare about 2000 growth characteristics of several pathogenic (disease-causing) E. coli with a non-pathogenic laboratory E. coli strain. At the Society for General Microbiology's meeting at Heriot-Watt University, Edinburgh, today (9 September) they reported that they had found that the pathogenic strains could survive in different conditions compared to the standard laboratory, non-pathogenic strain.
"The laboratory E. coli strain K-12 is one of the best understood organisms on Earth," said Dr Heurlier, "But because it has become so used to being grown in laboratory conditions, it may not react to stresses in the same way as pathogenic strains - such as E. coli O157:H7 can. Our research shows that there are definite growth and nutrition differences between E. coli strains and therefore results obtained with laboratory strains may not be typical of what happens in the 'real' world".