Multiple drug resistance Staphylococcus aureus isolated in foods of animal origin in Nairobi, Kenya

Abstract

Background: StaphylococcuS. aureus is the most important agent, which is known to cause a wide range of diseases in both human and animals. Extended use and misuse of antibiotics in agriculture, stock farming and in the treatment of human diseases, has contributed to the rapid increase of the number of bacteria that are resistant to antimicrobial agents.

Objective: To determine the occurrence of S. aureus in foods of animal origin and their reactions to commonly used antibiotic.

Design: A descriptive, cross-sectional, quantitative study.

Setting: Central Business District of Nairobi (CBDN) and its environment.

Subject: Samples of meat (n=280) and dairy products (n=140) were randomly purchased from various butcheries and supermarkets. Additional 251 samples of various pork products were also collected randomly from a nearby pig processing plant for comparison purposes. Baird-Parker agar with 2% egg yolk tellurite emulsion was used as growth medium for isolation of S. aureus. The typical culture confirmed positive of S. aureus were tested for antibiotic susceptibility to eight commonly used antibiotics using the disc diffusion method.

Result: Occurrence of S. aureus was 36.2% (152/420) and 39.4% (99/251) from the food outlets and meat processing factory respectively. Proportions of contamination from the two sources were not significantly different (p=0.400). Significantly, more contamination was observed in meat products (40.7%) compared to dairy products (25.0%) (p=0.001). Penicilin G (246; 99.6%) was the most resisted antibiotic followed by Ampicillin (230; 93.1).

Conclusion: The results of this study confirms that multi antibiotics resistant S. aureus strains are present not only in hospital setups, but also widespread in foods of animal origin.