Prevalence of and in neonatal diarrheic calves.

Neonatal calf diarrhea remains one of the most important problems faced by livestock, causing great economic losses. This study investigated the prevalence of and , especially enterotoxigenic   (ETEC), in diarrheic calves. Fecal samples were collected from 127 diarrheic calves up to 3 months of age at 12 farms from different governorates in Egypt. 119 bacterial isolates (93.7%) were recovered and the prevalences of and   in diarrheic calves were 18.1% and 75.6%, respectively. Serotyping of isolates revealed that Enteritidis and Typhimurium were the most prevalent serotypes, representing 60.9% and 30.4%, respectively, while Dublin was 8.7%. Serogrouping of   isolates showed that 10 O-serogroups were obtained where O and O were the most prevalent (17.7% of each). serotypes showed positive results with PCR test using oligonucleotide primer amplifying 521 bp fragment of gene of while 70% of   serogroups possessed ETEC virulent gene (). The antibiotic sensitivity test indicated that serotypes showed high sensitivity against enrofloxacin, spectinomycin and neomycin while   isolates showed high sensitivities against marbofloxacin, spectinomycin and neomycin only.