Bioburden and Antibiogram of Staphylococcus Aureus Isolated from Locally Fermented Milk Sold in Katsina Town, Katsina State

Abstract

Staphylococcal food borne intoxication is one of the most common forms of bacterial food-borne disease in many countries. Milk is a good substrate for S. aureus growth and among the foods implicated in staphylococcal food poisoning (SFP). The study aimed to evaluate the bioburden and antibiogram of Staphylococcus aureus isolated from locally fermented milk collected from four different locations within Katsina metropolis. A total of 40 samples were analyzed, out of which S. aureus was isolated from 17 samples, representing a contamination rate of 42.5%. The bioburden of S. aureus in the positive samples ranged from 1.9 x 10³ to 9.8 x 10³ CFU/mL, with mean bioburden values of 5.6 ± 2.3 x 10³, 5.1 ± 1.8 x 10³, 4.3 ±  1.7 x 10³, and 6.2 ±  2.4 x 10³ CFU/mL for Locations A, B, C, and D, respectively. Statistical analysis showed no significant differences in bioburden levels across the locations (p > 0.05). Antibiogram analysis of the S. aureus isolates revealed varied resistance patterns, with resistance observed against commonly used antibiotics, including penicillin and tetracycline. However, isolates showed sensitivity to antibiotics such as vancomycin and ciprofloxacin. The findings highlight the risk of consuming locally fermented milk contaminated with S. aureus, which could pose a public health threat, especially if the bacteria exhibit multidrug resistance. The study concludes that locally fermented milk is a potential source of S. aureus contamination, emphasizing the need for improved hygiene practices during production and handling. It also calls for routine microbial testing and antibiotic stewardship programs to mitigate the spread of antimicrobial resistance. The findings underscore the importance of regulatory oversight and public education to ensure the safety of locally fermented milk.