| Popis: |
Mastitis is one of the most serious healthy and economic problems in all dairy sheep and goat flocks. Examination of 200 milk samples collected from apparently healthy sheep and goats using California mastitis test (CMT) showed that 94 (47%) were CMT positive. Standard methods for isolation and identification of E. coli could identify 19 strains. Five different serogroups were successfully identified among 19 E. coli strains, the serogroups were O1 (21.1%), O26 (21.1%), O114 (15.8%), O148 (15.8%) and finally O125 (10.4%), in addition to 3 untypable strains. The antimicrobial susceptibility results for erythromycin and cefoxtin revealed all E. coli isolates were resistant to erythromycin (100%) followed by high frequencies of resistance observed to cefoxtin 18 isolates (94.7%). Phylogenetic grouping of E. coli by triplex PCR using two genes (chuA and yjaA) and an anonymous DNA fragment tspE4C2 indicated that 5/6 were B2 group and 1/6 was A group. Detection of virulence genes of 6 E. coli. isolates showed that 2/6 harbored eaeA gene and none of 6 isolates harbored CFA/I gene. While, the mph A erythromycin resistance gene were present in 4/6.but 2/6 isolates harbored bla CTX cefoxitin resistance gene. |
