ISSN 110-2047 ALEX. J. VET. SCIENCE 2010 VOL. 30 NO. 1: (137-147) Alex. J. Vet. ,Sci., Vol. 30, No. 1, April 2010 137 VIRULENCE FACTORS OF ESCHERICHIA COLI ISOLATED FROM DIARRHEIC SHEEP AND GOATS MOUSA, M.S. 1 ; AKEILA, M.A. 2 ; KHALIL, S.A. 2 AND ABDELLRAZEQ, G.S. 2 1 Fac.Vet.Med ., Omar Elmokhtar Univ., Libya. 2 Fac.Vet.Med ., Edfina, Alex.Univ., Egypt. ABSTRACT This study was aimed to investigate some virulence factors of E. coli from diarrheic sheep and goats. This aim was achieved by determining the following points 1) Incidence of E. coli from rectal swabs collected from diarrheic sheep and goats 2) Correlation between E. coli isolates with regards to age 3) Haemolytic activity of E. coli isolates 4) Serotyping of the pathogenic E. coli 5) Detection of enterotoxin, astA and verotoxin genes of E. coli isolates using Polymerase chain reaction and 6) Antibiogram to the E. coli isolates. E. coli was isolated at highest percentage from diarrheic sheep at age ranged from 1 to 6 month, highest percentage from diarrheic sheep and goats aged from 7 to 12 month. E. coli isolated from diarrheic sheep gave alpha, beta and gamma hemolysis at percentage of 66.7 %, 18.2 % and 15.1%, respectively. Moreover, E. coli isolated from diarrheic goats gave alpha, beta and gamma hemolysis at percentage of 55%, 30% and 15 %, respectively. Results of Congo red test revealed that 90.9 % of E .coli isolated from diarrheic sheep and 90% isolated from goats gave positive results. The results presented in table (7) revealed that serotype O26 was the most E. coli serotype (31.4% ) that gave a positive Congo red followed by E. coli serotype O78 (22.9%) and E. coli serotype O86 (17.1%). The results of antibiotic sensitivity of E. coli to chemotherapy revealed that it was sensitive to levofloxacin, norfloxacin, ofloxacin and trimethoprim/sulfamethoxazole. On the other hand E. coli was resistant to colistin and neomycin. Results of detection of verotoxin 2 gene of E. coli isolated from diarrheic sheep and goats revealed that the gene could not be detected in all examined E. coli isolates (7 isolates). On the other hand, results of detection STa gene in E. coli isolated from diarrheic sheep and goats revealed that 5 out of 7 E. coli isolates (71.4 %) were detected. astA gene of E. coli isolated from diarrhoeic sheep and goats was detected in all the examined isolates (7 isolates). It could be concluded that E. coli isolated from diarrhoeic sheep and goats was pathogenic and producer for enterotoxin and astA. Moreover, PCR is a simple and rapid method for detection of STa , astA and VT2 genes of E. coli. INTRODUCTION Escherichia coli (E. coli) is a bacterium that commonly lives in the intestines of people and animals. There are four major categories of diarrhoegenic E. coli, namely: enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC). These categories of E. coli differ in their epidemiology and pathogenesis and their O: H serotypes (Levin, 1987).