Purpose: This study was conducted to determine the prevalence of resistance Salmonella spp. isolated from milk and milk products in Tamale, Ghana.
Methods: Three hundred milk and milk-related samples were examined. Isolation of Salmonella species was done according to the U.S.-FDA Bacteriological Analytical Manual. Antibiotic susceptibility tests were performed by disc diffusion and the results were interpreted using the CLSI guidelines. Prevalence data was analyzed using SPSS Version 17.
Results: Of the 300 samples examined, 7.3% (22) were positive for Salmonella spp. Raw wagashie was most contaminated (24.0%; 12/50), followed by fried wagashie (8.0%; 4/50), pasteurized milk (6.0%; 3/50), left hand swab of milk sellers (4.0%; 2/50) and right-hand swab of milk sellers (2.0%; 1/50). Salmonella spp. were not isolated from brukina (0.0%; 0/50). There were no significant differences (P > 0.05) among fried wagashie, pasteurized milk, hand swab of milk sellers, or brukina samples. The prevalence of Salmonella in raw wagashie was significantly higher (P < 0.05) than the other samples examined. From the 22 Salmonella spp. isolates examined against 8 different antibiotics, a high percentage (86.0%) was resistant to erythromycin. Resistance to gentamycin (14.0%) and tetracycline (14.0%) were relatively low. Salmonella spp. isolates were highly susceptible to ciprofloxacin (100.0%), chloramphenicol (91.0%), ceftriaxone (91.0%), sulphamethoxazole/trimethoprim (91.0%), tetracycline (86.0%), and ampicillin (86.0%). Of the 22 Salmonella spp. isolates, 14 were resistant to only one antibiotic, 4 were resistant to two antibiotics, and 2 were resistant to three antibiotics. Two Salmonella spp. isolates were not resistant to any of the antibiotics tested.
Significance: This study create the awareness that some milk, milk products, and hands of milk sellers in the Tamale Metropolis are contaminated with Salmonella spp., which are resistant to some antibiotics. Therefore, consumers of milk in this metropolis are at risk of Salmonella spp. infection.