Abstract
To assess the most common bacterial causes of pneumo-enteritis in small ruminants in three Egyptian provinces, a total of 248 rectal and nasal swabs and 19 tissue samples were collected from diarrheic and dead lambs and goat kids and examined by the standard bacteriological techniques. All the isolates were examined for their antibiotic sensitivity. Finally, the virulence genotyping of E coli serogroups was carried out by PCR. The data showed that 90.34% and 73.79% of the rectal and nasal swabs were bacteriologically positive respectively, with the highest percentage of positive samples were observed in neonates (85%) comparing with 80% in adult samples. Escherichia coli was the highest percentage followed by Staph. aureus and then Salmonella (70.99%, 5.34%, and 3.82% respectively). While, in the case of tissue samples, the highest percentage of bacteria were isolated from the liver with E. coli is predominant (31.58%). The isolated aerobic bacteria showed a multi-drug resistance. The common E .coli serotypes are O114, O103, O8, O26, O108, O148, O86, O78, O111, O18. These serotypes were further examined for the presence of Shiga toxin (Stx1) and attaching effacing (eaeA) encoding genes. The data showed that Stx1 and eaeA genes were produced by 64.85% (9/14) of and 42.85% (6/14) of these serogroup respectively. The production of both was noticed in only 35.71% (5/14) of E. coli serogroups, while 21.43% (3/14) serogroups did not contain any of these genes. The data collectively showed that E. coli is the main cause of pneumo-enteritis amongst small ruminants and severity of infection mainly depends on the production of certain virolence encoding genes including Stx1 and eaeA genes. Further investigations are still required to verify their precise role in pneumo-enteritis pathogenesis.

Key words: Small ruminates, pneumo-enteritis, E. coli, Virulence genes, antibiotic resistance