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

Abstract

Diarrhea is an important hygienic problem in under development countries. Among pathogenic agents<em> Escherichia coli</em> is the most etiologic agent of diarrhea in children below five years old. Some<em> E. coli</em> strains produce cytotoxins that have cytopathic effect on vero cell and identified as verotoxin. This study performs for resolve frequency of Vero Toxigenic<em> Escherichia coli</em> (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 <em>Esherchia coli</em> (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.