SOME BACTERIOLOGICAL STUDIES ON SALMONELLA INFECTION IN BUFFALO CALVES USING PCR TECHNOLOGY

Abstract

In this study, out of 195 fecal samples collected from diarrheic calves at different localities from a private farm located in Kafr el-Sheik and Al Qualubia provinces, 120 of them were from Kafr el-Sheik and 75 were from Al Qualubia provinces. 12 were positive for Salmonella with a percentage of 6.1%. The typing of Salmonella isolates include S.typhimurium, S. typhimurium Lac+, S.entertidis, S.dublin, S.gaillac, S.derby, S.virginia, and S.wingrove which is one strain for each. Antibiogram for isolated strains revealed that all serogroups of Salmonella isolates were highly sensitive to enrofloxacin, levomicin, and neomycin. However, for tobramycin, amoxicillin, oxytetracycline, colistinsulphate and ampicillin, the total isolates were resistant. Variable results were recorded with the remaining tested antimicrobial agents. Real-time PCR test is a rapid, reproducible, and is a robust method for detecting Salmonella enteritidis and Salmonella typhimurium using primers SEFA-2 and SEFA-4 for S.enteritidis, fli 15, and tym for S.typhimurium. The specificity of the reaction was confirmed by the Tm, which was consistently specific for the amplicon obtained. The mean peak Tm obtained with curves specific for serotype S. enteritidis was 83.03°C, and was 84.04°C for S.typhimurium. The results of this study demonstrate that the SYBR Green I real-time PCR constitutes an effective and easy-to-perform method for detecting S. enteritidis and S. typhimurium in clinical samples.