Antimicrobial resistance of Staphylococcus aureus strains from patients with urinary tract infections in Yenagoa, Nigeria

Context: Antimicrobial resistance in Staphylococcus aureus infections is a global public health problem resulting in very limited treatment options. This study determined the antimicrobial resistance pattern of S. aureus strains from urinary tract infections (UTIs) to commonly used antimicrobial agents. Materials and Methods: Midstream urine specimens of UTIs symptomatic patients from public and private health institutions in Yenagoa, Nigeria were collected, cultured, and screened for common pathogens using standard microbiological protocols. The antimicrobial susceptibility of identified S. aureus strains was evaluated using disc diffusion and agar dilution techniques. Results: A total of 46 (33.6%) S. aureus strains were identified from 137 growths of the 200 urine specimens. All the S. aureus isolates were methicillin resistant; they exhibited total resistance to ampicillin, 97.8% to tetracycline, 80.4% to chloramphenicol and co-trimoxazole, 73.9% to gentamicin, 69.6% to augmentin and vancomycin, 54.3% to cefuroxime, 39.1% to nitrofurantoin, 34.8% to ofloxacin, and 32.6% to ciprofloxacin. The isolates were commonly resistant to 7 (77.8%) of the nine classes of antimicrobial agents used in this study and 45 (97.8%) of all the isolates were multi-resistant. Conclusion: The faster rate at which this pathogen is developing resistance to nitrofurantoin and fluoroquinolones is reducing their usefulness in the empiric treatment of uncomplicated UTIs. Thus, the need to adopt new strategies in the control of antibiotic resistance in this country cannot be overemphasized.