Prevalence and antimicrobial susceptibility of Salmonella in poultry farms and in-contact humans in Adama and Modjo towns, Ethiopia

Consumption of contaminated poultry and poultry products represents a common source of nontyphoidal Salmonella infection. Little is known on the status of Salmonella and their antimicrobial susceptibility in poultry farms in Ethiopia. This study investigated the prevalence, serotype distribution, and antimicrobial susceptibility of nontyphoidal Salmonella among poultry farms in Adama and Modjo towns. Three hundred thirty-four cloacal swabs, 384 fecal droppings of birds, 59 feed, 59 floor swabs, and 36 stools from in-contact humans were collected and processed for Salmonella isolation. Isolates were tested for their susceptibility to 15 antimicrobials using Kirby-Bauer disk diffusion assay. Seventeen (28.8%) of the farms and 24 (2.9%) of the samples from poultry farms and 2.8% (1/36) of stool samples of humans in-contact with poultry were positive for Salmonella. Most of the isolates (n = 21) were recovered from fecal droppings of birds while the remaining isolates were recovered from floor swab samples (n = 2) and cloacal swab sample (n = 1). Only three Salmonella serovars: S. Haifa (n = 14, 56%), S. Anatum (n = 7; 28%), and S. Give (n = 4; 16%) were detected. Poultry farms in Adama town, large flock sized farms, and farms that used antimicrobials were significantly associated with the occurrence of Salmonella (p < .05). Twenty (80%) and 19 (76%) of Salmonella isolates were resistant to streptomycin and tetracycline, respectively. Nineteen (76%) of the isolates were resistant to two or more antimicrobials. Detection of multidrug-resistant strains of Salmonella in poultry farms suggests the need for detailed epidemiological and molecular studies to establish sources of acquisition of resistant Salmonella strains.