Investigation of antibiotic resistance among Staphylococcus aureus strains of human and bovine origin

The objective was to investigate antibiotic resistance patterns of Staphylococcus aureus strains isolated from human and bovine by using Kirby-Bauer antibiotic disk test as well as methicillin resistance by using polymerase chain reaction (PCR). Among 114 S. aureus strains samples collected from patients hospitalized in various clinics of Harran University Medical School the number and percent of antimicrobial resistant strains were as follows: 114 (100%) ampicillin, 108 (94.7%) penicillin G, 76 (66.6%) rifampin, 75 (65.7%) cefoxitin, 71 (62.2%) cefuroxime, 74 (64.9%) oxacillin, 73 ( 64%) ciprofloxacin, 74 (64.9%) norfloxacin, 70 (61.4%) gentamycine, 66 (57.8%) imipenem, 64 (56.1%) amoxicillin-clavulanic acid, 61 (53.5%) tetracycline, 37 (32.4%) erythromycin, 38 (%33.3) clindamycine, 11 (9.6%) sulphamethaxazole-trimethoprim and 8 (7%) vancomycine. None of vancomycin resistant S. aureus was found by E-test. Among 64 S. aureus strains isolated from subclinical bovine mastitis, all were resistant to penicillin and ampicillin while all were found to be highly sensitive to oxacillin, cefoxitin, imipenem, cefuroxime, vancomycin, ciprofloxacin, norfloxacin, rifampin and sulphamethaxazole-trimethoprime. The number and percent of antimicrobial resistance to other antibiotics were as follows: 13 (20%) gentamicine, 6 (9.3%) erythromycine, 5 (7.8%) clindamycine, 4 (6.2%) tetracycline, 1 (1.5%) amoxicillin-clavulanic acid. All strains were resistant to penicillin and ampicillin. PCR analysis showed that 76 (66.6%) of total 114 methicillin resistant S. aureus (MRSA) strains of human origin had mecA gene. This gene was not detected in bovine strains. In conclusion, the results of the present study indicated that the incidence of antibiotic resistance of S. aureus strains isolated from humans was higher than that from cattle, penicillin and ampicillin resistance of S. aureus strains of human and cattle origin were highly widespread as well as the methicillin resistance was highly prevalent among S. aureus strains of human origin while it was absent or low among those of cattle origin