DETECTION AND ANTIBIOTIC RESISTANCE OF SALMONELLA ISOLATES FROM SELECTED POULTRY FARMS IN DAR ES SALAAM, TANZANIA.

• DOI: 10.1099/acmi.0.000879.v2
• Publication Date: 2025-01-20T11:32:01Z
• Authors: Saxon Joseph Mwam...; Adelard B. Mtenga; Augustino A. Chen...; Abubakar S. Hoza

Introduction

Salmonella, one of the most frequent foodborne bacteria, is linked to 155,000 annual mortality and 93.8 million foodborne illnesses. Rampant use of antibiotic agents to combat Salmonellosis in poultry has contributed to the emergence of resistance against commonly used antibiotics.

Methodology

A cross-section study was conducted between January and June 2023. Purposive sampling was used to select farms, poultry faecal droppings were collected to determine the occurrence of multidrug-resistant (MDR) Salmonella spp. Samples were examined for the presence of Salmonella by standard microbiological techniques. Conventional biochemical tests and molecular methods such as PCR and partial DNA sequencing were used for the identification of Salmonella isolates. Antimicrobial susceptibility testing was performed to identify Salmonella isolates resistant to seven commonly used classes of antibiotics.

Results

The overall Salmonella spp isolated from faecal droppings from the selected farms was 6.04% (n=48). Of the PCR-confirmed isolates, 64.3% (n=18) were resistant to more than two classes of antibiotics and hence considered MDR. The highest resistance was observed with ampicillin (92.9%), followed by tetracycline (69%), ciprofloxacin (42.9%), sulfonamide (42.9%), gentamicin (35.7%), and azithromycin (28.9%). All the isolates were susceptible to chloramphenicol (100%). Twenty-eight (28) isolates were sequenced and only sixteen (16) sequences met the criteria for phylogenetic analysis. All the sixteen (16) Sequences clustered together with Salmonella enterica sub spp. enterica with accession number EU348369 which was isolated from chickens, pigs, and foods.

Conclusion

The observed high level of antibiotic resistance found in this study could be attributed to the unwarranted use of antibiotics. To limit the use of antibiotics in poultry farming at the farm level, immediate action is needed including advocating for prudent use of antibiotics in poultry production systems by strengthening extension services to poultry farmers and use of farm biosecurity.