Molecular characterization of Methicillin resistant Staph. aureus from poultry farms in Kano State, Nigeria

Abstract

The increasing rate of drug resistance associated with Methicillin resistant Staph. aureus is not only a problem in clinical sector but also in livestock disease treatment and management. This study was set out to evaluate the incidence of Methicillin resistant Staph. Aureus from poultry farm birds and the farm workers, and also to evaluate the likelyhood of cross-infection between the birds and the farm workers in Kano State, Nigeria, using standard microbiological and molecular methods. The results showed that out of the 1260 samples collected, 98(33.8%) isolates were confirmed to be Staph. aureus. Using disc diffusion method, the antibiotics susceptibility test results showed that 68 (69.4%) of the isolates were susceptible to cefoxitin while 30 (30.6%) were resistant. While 100% of the isolates were resistant to Ampicillin and Amoxicillin, 93.3% to Oxytetracycline, 90% to Chloramphenicol, 80% to Erythromycin, 76.7% to Oxacillin, 63.3% to Trimethroprim/Sulphamethozaxole, 30% to Ciprofloxacin and 26.7% to Gentamicin. The result also showed that 83.3% of the isolates had multiple antibiotic resistance index (MARI) of > 0.3 and were also multidrug resistant (MDR) while 16.7% had MARI ≤ 0.3. The molecular analysis showed that all the isolates were Staph. aureus of 800bp, 66.7% of the MDR isolates possess MecA gene (162bp), while 33.3% had MecA of500bp. Further analysis showed that 3 of the seven housekeeping genes (pta, gmk and yqil) were also present in the MDR isolates at 43.3%, 20% and 16.7% respectively while 10% express spa typing. The results also showed that there is a correlation between phenotypic cefoxitin resistance and carriage of MecA gene. The implication of these results in cross infection between the farm workers and the poultry birds as well as the danger of transfer of these resistant isolates to the community is discussed in this report.

Key words: Staph. aureus, cefoxitin resistance, poultry farms, housekeeping genes, spa typing,  MDR.