Characterization of antibiotic resistant gene in Staphylococcus aureus isolated from surgical wounds

Abstract

Background: In the field of surgery wound infections have been a problem. Staphylococcus aureus, Escherichia coli, Proteus species, Klebsiella species, Streptococcus species, Enterobacter species, Pseudomonas species and species of staphylococci are frequently isolated from wound. This study was carried out to determine the prevalence of different pathogens in surgical wounds and their antimicrobial susceptibility patterns. Methods: Pus swabs from each patient was collected aseptically, and inoculated on culture media. Isolates were characterized, identified, and their antibiotic susceptibility patterns were determined using the Kirby-Bauer diffusion method. Results: Out of 300 surgical wound specimens analyzed, 208 samples were positive culture among which Staphylococcus aureus was most frequent pathogen with 103 (49.51%). The other 33 (15.86%) isolates were Pseudomonas aeruginosa followed by 27 (12.98%) isolates of Klebsiella 25 (12.01%) isolates of Proteus and 20 (9.61%). isolates of E.coli respectively. The antibiotic susceptibility of Staphylococcus aureus was checked. Conclusions: It was observed that 103 isolates of S. aureus were resistant to Augmentin 65.04% to Sparfloxacin 59.22% to Amikacin 57.28% to Cefuroxime 57.28% to cefotaxime 56.31% to Ceftazidime 53.39% to Fusidic acid 48.54% to Ciprofloxacin 39.80% to Methicillin 37.86% to Gentamicin 28.15% to Meropenem 13.59% to Imipenem 5.82%. PCR assay for the detection of clinically relevant antibiotic resistance gene of S. aureus was done. Fragments of mecA (encoding methicillin resistance) gene were amplified and commercially sequenced which showed insertion at three sites; 480-481: T, 484-485: T, 464-465: G.

Keywords

• Antibiotic resistance genes
• Staphylococcus aureus
• surgical wounds
• Imipenem