The Distribution ofEscherichia coliSerovars, Virulence Genes, Gene Association and Combinations and Virulence Genes Encoding Serotypes in PathogenicE. coliRecovered from Diarrhoeic Calves, Sheep and Goat

Abstract

Summary Ruminants, especially cattle, have been implicated as a principal reservoir of one of the enterovirulent Escherichia coli pathotypes. The detection of the virulence genes in diarrhoeic calves and small ruminants has not been studied in Egypt. To determine the occurrence, serotypes and the virulence gene markers, stx1, stx2, hylA, Flich7, stb, F41, K99, sta, F17, LT‐I, LT‐II and eae, rectal swabs were taken from diarrhoeic calves, sheep and goats and subjected to bacterial culture and PCR. The E. coli prevalence rate in the diarrhoeic animals was 63.6% in calves, 27.3% in goat and 9.1% in sheep. The 102 E. coli strains isolated from the calves, goat and sheep were 100% haemolytic non‐verotoxic and fitted into the Eagg group. The isolates belonged to seven O serogroups (O25, O78, O86, O119, O158, O164 and O157). The eae gene was detected in six of the strains isolated from the calves. The 102 bovine, ovine and caprine E. coli strains isolated in this study were negative for stx1, stx2, F41, LT‐I and Flich7 genes. The highest gene combinations were found to occur in the form of 24/102 isolates (23.5%) that carried the F17 gene predominantly associated with eaeA, hylA, K99 and Stb genes in the calves, while the hylA, K99 and Sta were the only genes found to be in conjunction in both calves and goats (6/102; 5.9% each). Our data show that in Egypt, large and small ruminants could be a potential source of infection in humans.

Identification of serotypes and virulence markers of Escherichia coli isolated from human stool and urine samples in Egypt

“…These targets were part of a large set of virulence genes described by Osman et al [3] Reference strains used were E. coli ATCC35150 (O157:H7, stx1, stx2, eae, hly) and S. aureus ATCC29737 (negative control).…”

“…[3] The cells were observed microscopically for 72 h and the cytotoxicity titres determined; the highest toxin dilution that caused lysis of 50% of the cell monolayer was taken as the titre.…”

“…The lysate was centrifuged as before and 200 μl of the supernatant were used directly as the template for the PCR. [3] DNA samples were dissolved in Tris-EDTA buffer (10 mM Tris, 1 mM EDTA at pH 8.0), and the DNA concentration was determined in micrograms per millilitre at an optical density reading of A 260 . The template DNA concentration used was 200 ng/ml.…”

Zoonotic Importance of Some Pathogenic Bacteria Isolated from Small Ruminants' Milk and Hands of Dairy Workers

“…Ruminants are usually identified as one of the important reservoirs for EPEC/STEC (also called verotoxinproducing E. coli). In Egypt, cattle, goats and sheep are considered a potential source of E. coli infection to humans, with the important serotypes are O26, O86, O111, O126, O127, O157, O158 and O164 [34]. They shed the bacteria into the environment throughout their faeces without even suffering from clinical disease, thus allowing meat and milk contamination causing human foodborne illness following consumption of such food [35].…”

IMMUNIZATION OF MICE WITH KILLED E. coli K99 VACCINE FOR PROTECTION AGAINST COLIBACCILLOSIS

“…Osman, et al [5] report that the large and small ruminants could be a potential source of infection with enterovirulent Escherichia coli pathotypes in humans in Egypt. Different vaccines have been developed using ETEC strains producing K99 and F41.…”