Occurrence, Risk Factors, and Antibiotic Resistance Patterns of Salmonella Isolates Obtained From Dairy Farms in Gondar Town, Northwest Ethiopia.

Abstract

Background: Salmonellosis is a foodborne diarrheal disease with significant public health and economic implications for humans and animals. Nevertheless, its epidemiological effects and multidrug resistance remain poorly studied in the study area. Methods: A cross-sectional study was conducted from March to August 2022 to determine the occurrence, risk factors, and antibiotic susceptibility patterns of Salmonella isolates in the study dairy farms. A total of 232 samples (200 study animals and 32 bulk tank milk) were collected from purposively selected dairy farms in the study area. Again, fecal and bulk tank milk samples were collected, pre-enriched, and cultured to examine the presence of Salmonella following standard techniques. The pure 30 isolates were also subjected to a Kirby-Bauer disk diffusion test on Muller-Hinton agar to assess their antibiotic susceptibility patterns. Binary logistic regression analysis in Statistical Package for Social Sciences (SPSS) Version 25 was used to determine the strength of the risk factors associated with the occurrence of this disease. Findings: The overall prevalence of Salmonella isolates was 12.9% (30/232) across all samples. Among these, 11.5% (23/200) of the fecal samples from the study animals and 21.9% (7/32) of the bulk tank milk samples tested positive for this disease. A statistically significant association was observed between the presence of the Salmonella isolates and the age of the study animals, farm size, bedding, and udder washing practices. The isolates also showed the highest resistance to ampicillin (100%) and tetracycline (96.7%). Conversely, the isolates were most sensitive to ciprofloxacin (100%) and kanamycin (90%). Conclusions: Generally, the high presence of Salmonella isolates and its resistance to drugs pose significant economic and public health challenges. Thus, it is crucial to implement improved management practices and appropriate antibiotic therapies in the study dairy farms.