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

There is presently an increased rate of resistance by methicillin resistant Staph. aureus against commonly prescribed antibiotics for Staph aureus infection. This strain of Staph. aureus is not only a problem in clinical sector but also in livestock disease treatment and management as transferability of this resistant gene in zoonotic outbreak might be possible. This study was set out to evaluate the incidence of methicillin resistant Staph. aureus from poultry farms birds and the farm workers, and also to evaluate the likelihood of cross-infection between the birds and the farm workers in Kano State, Nigeria. Samples were collected using standard microbiological techniques. Antibiotic susceptibility was also carried out using disc diffusion method while genes that influence methicillin resistant were evaluated using PCR method. The results showed that out of the 1260 samples collected, 98 isolates were confirmed to be Staph. aureus. The antibiotics susceptibility test results showed that 30.6% (30) of the Staph. aureus isolates were resistant to cefoxitin (a phenotypic test for methicillin resistant) while 69.4% (68) were susceptible. The methicillin resistant isolates were observed to exhibit (100%) 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% (25) 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 harbored MecA gene (162bp), while 33.3% had MecA of 500bp. Further analysis showed that 3 of the 7 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.