Detection of multidrug resistant Salmonella spp. from healthy and diseased broilers having potential public health significance

Multidrug resistant (MDR) Salmonella spp. poses significant global public health concern by causing food-borne infections. This study aimed to detect MDR Salmonella spp. from healthy and diseased broiler chickens in the Mymensingh and Jamalpur districts of Bangladesh. Total 70 samples comprising feces (n=20), chicken meat (n=30), and visceral organs i.e. liver, lung, and kidney (n=20) were collected. Salmonella were isolated and identified by culture, biochemical tests and PCR. The antibiogram study was performed by the disk diffusion method. By PCR, 30% (21/70; 95% CI: 19.32-40.05%) samples were positive for Salmonella spp., of which significantly (p=0.005) higher occurrence were detected in feces (50%; 95% CI: 29.93-70.07%) compared to chicken meat (10%; 95% CI: 3.46-25.62%) and visceral organs (40%; 95% CI: 21.88-61.34%). By antibiogram, all the Salmonella isolates were resistant to amoxicillin, and frequently (90.48-19.05%) resistant to tetracycline, ceftazidime, chloramphenicol, colistin, and ciprofloxacin. The significantly higher resistance of chloramphenicol, tetracycline, and ceftazidime were observed in the internal organs of broilers. Interestingly, 80.95% (17/21; 95% CI: 59.99-92.33%) Salmonella isolates were MDR in nature. The range of multiple antibiotic resistance (MAR) index of Salmonella isolates varied from 0.29 to 0.86. The high occurrence of MDR and MAR Salmonella in broilers detected in our present study could reveal a high risk to public health and these organisms could be transmitted to humans through the food supply. We suggest that effective prevention and control measures should be implemented to reduce their potential contamination and to minimize the emergence of antibiotic resistance.