Current Antibiotic Resistance Trend in Clinical Isolates of Staphylococcus aureus from a Tertiary Care Hospital

Background: Staphylococcus aureus (S. aureus) has remained always an important pathogen of common infections acquired in community and as well as serious nosocomial infections. With advent of penicillins and cephalosporins, infections could be effectively treated, but with the global emergence of Methicillin Resistant Staphylococcus aureus strains (MRSA) physicians were again left with limited treatment options. This scenario of increasing resistance is even more intense and challenging for developing countries like Pakistan. Hence with this background the study was carried out to establish the frequency of MRSA in clinical specimens and look into the available antibiotic treatment options. Methods: Samples of pus, blood, urine, body fluids and catheter tips submitted for culture in Microbiology department between August to September 2012, from outdoor and indoor adult patients of Pakistan Institute of Medical Sciences Islamabad, yielding growth of S. aureus were included in the study. After identification by standard methods, antibiotic susceptibility of the isolates was performed by Kirby Baeur disc diffusion method. The study was retrospective descriptive and observational. Results: Total 106 S. aureus were isolated. 45.3% of them were MRSA and majorities were from pus samples of hospitalized patients. All MRSA were 100% sensitive to vancomycin, whereas 87.5% to chloramphenicol. To rest of the non – beta lactam drugs, resistance of 80% or more was noted. Conclusion: S. aureus is a common clinical isolate from patients in this region of Pakistan and significant number were MRSA especially from hospitalized patients. Treatment options are limited to vancomycin and chloramphenicol.