Carriage and antimicrobial resistance of non-typhoidal Salmonella in cattle slaughtered in Ambo municipality abattoir, West Shewa zone, Oromia, Ethiopia - a point prevalence survey

Abstract

Cattle are reservoir for non-typhoidal Salmonella (NTS) serovars which are important foodborne zoonosis worldwide. A cross-sectional study was undertaken from October, 2015 to May, 2016 to estimate the prevalence and assess antimicrobial susceptibility profiles of NTS isolated from slaughtered cattle following standard microbiological technique. A total of 300 samples (150 mesenteric lymph nodes and 150 feces) from 150 cattle slaughtered at Ambo municipality abattoir were investigated. Standard disc-diffusion method was used
for antimicrobial susceptibility testing of the isolates. Chi-square and Fisher’s exact tests were used to assess association between NTS prevalence and potential risk factors. An overall NTS prevalence of 8% (95 % confidence interval [CI]: 4.2-13.6%) was found at animal level. At sample level, NTS prevalence of 5.6% (17/300) (95% CI: 3.3-8.9%) was found. Prevalence of NTS in mesenteric lymph nodes and fecal samples was 6.6% and 4.6%, respectively. There was no significant difference in prevalence of NTS with respect to sex, age groups and body condition (p> 0.05). However, significantly higher prevalence was seen in animals from Guder market (12.5%) than Ambo market (1.6%) (p< 0.05). The highest level of antimicrobial resistance was observed for amoxicillin clavulanic acid (100%) and ampicillin (100%) followed by streptomycin (41.1%). Six of the 17 NTS isolates (35.3%) showed multi-drug resistance (MDR) to three or more antimicrobial classes. In conclusion, high percentage of NTS isolates were MDR posing public health threat to consumers. Improved hygiene, education, prudent use of antimicrobials and further large scale epidemiological studies are suggested.

Keywords: Antimicrobial resistance; Cattle; Ethiopia; Non-typhoidal Salmonella;
Prevalence