Prevalence, organ distribution and antimicrobial susceptibility profile of Salmonella isolated from chickens purchased from markets in selected districts of West Shoa, Ethiopia

Salmonella is one of the major causes of heavy losses in chicken and foodborne diseases worldwide. The current study was conducted from  November 2015 to May 2016 to estimate the prevalence of Salmonella and determine the antimicrobial susceptibility of isolates in chickens. Chickens (n=205) were purchased from local markets of five selected districts of West Shoa Zone, Central Ethiopia. Following clinical examination, chicken were euthanized and 2-3 ml of blood sample was collected immediately. Then after postmortem examination, samples were collected from the liver, kidney, ovary, and spleen. The slide agglutination test was used to assess the seroprevalence of Salmonella antibodies. Isolation of Salmonella was performed according to the ISO-6579 procedure. The isolates were subjected to antimicrobial susceptibility testing (using 13 antimicrobial drugs) following the Kirby-Bauer disc diffusion method. The seroprevalence of Salmonella antibodies was 63.5% (95% CI: 55.9-70.5). The isolation rate of Salmonella was 19.0% (95% CI: 13.9-20.1) at the chicken level and 7.3% (95% CI: 5.5-9.4) at the organ level. The detection rate was 11.2%, 7.0%, 6.1%, and 4.4% for spleen, liver, ovary, and kidney, respectively. The majority of the Salmonella isolates were susceptible to norfloxacin (97.4%) and chloramphenicol (92.3%). All the 39 isolates were resistant to amoxicillin, tetracycline, and nitrofurantoin. Three multidrug resistance patterns to six antimicrobial classes were observed. Four isolates were resistant to five antimicrobial classes. Therefore, regular  surveillance of Salmonella and its antimicrobial resistance is needed for a better understanding of the epidemiological dynamics. Awareness creation for chicken farmers about improving farming practices and the risks of antimicrobial resistance warrants special attention. Keywords: Antimicrobial susceptibility; Chicken; Prevalence; Salmonella; Ethiopia