Study on properties of enterohaemorrhagic Escherichia coil O157 isolates and their survival under different conditions

摘要

During the period of 2004-2006, 955 samples of food and clinical material were collected from the Slovak Republic and Belgium. Of the total number of 216 food samples originating from the Slovakia territory, the authors obtained 5 isolates (2.31%) of Escherichia coli O157. Three E. coli 0157 (2.30%) isolates were obtained during the examination of 130 samples of slaughter animals from the Belgium territory. In Slovakia no occurrence of E. coli 0157 was proved in any sample of clinical material or environment (altogether 36 samples). On the contrary, of 573 clinical and environmental samples from Belgium the presence of the respective pathogen was proved in 50 cases (8.73%). The authors studied some attributes of the recovered E. coli 0157, confirmed by immunomagnetic separation (IMS) and polymerase chain reaction (PCR). The results indicate that the isolates are capable of surviving for 15 min at 70 degrees C. The acidic environment, which is characteristic for fermentation of cheese (pH 4-4.5), had no devitalisation effect. The E. coli food isolates survived in a wide range of pH (2-11) while with clinical isolates the pH range of survival was from 2.5 to 10.5. The addition of NaCl in concentrations ordinarily used in food industry (3-6%) failed to inhibit the growth of pathogens.