Survey frequency of verotoxigenic Escherichia coli (VTEC) in raw milk at Kerman city

Diarrhea is an important hygienic problem in under development countries. Among pathogenic agents Escherichia coli is the most etiologic agent of diarrhea in children below five years old. Some E. coli strains produce cytotoxins that have cytopathic effect on vero cell and identified as verotoxin. This study performs for resolve frequency of Vero Toxigenic Escherichia coli (VTEC) in Kerman city. Samples include 375 raw milk sample that obtained from city and 122 raw milk samples that collected from cattle farms. VTEC strains were serotype by Entro Pathogenic Esherchia coli (EPEC) antiserum. Verotoxin were measured by using vero cell. The results of this research show that from 375 raw milk samples (75.45 %) that prepared from Kerman city 7 samples (1.85 %) were contaminated and from 122 samples (24.55 %) that prepared from cow growth two samples have contamination with VTEC. Neutralization experiment show that from 9 VTEC strains that isolated from raw milk, 5 strain (55.5%) produce VT1 and 3 strains produce VT2 (33.3 %). Also one strain (11.11 %) produces VT1 and VT2. Degree of contamination within milks that sold in city than milk that prepare from cow growth have not any significant difference (P= 0.613). This study show VTEC have very important in Kerman city but O157:H7 serotype in the Kerman city have low frequency.