FREQUENCY OF S. AUREUS IN SEPTIC WOUND INFECTIONS AT A TERTIARY CARE UNIT

Background: Skin plays a pivotal role in protecting against micro-organisms. Damage to skin through cut, surgical incision, burn and road traffic accident etc. make it susceptible for micro-organism to invade our body. Septic wounds further put stress on immune system of already injured person, hence increase morbidity and mortality. Approximately 30% of the human population is colonized with Staphylococcus aureus. It is a leading cause of wound complication, soft tissue and skin infections, infective endocarditis, bacteremia and sepsis etc. Objective: Aim of this study is to determine frequency of Staphylococcus aureus in septic wound infections. Methodology: It was a cross sectional study done at surgical wards, burn center, orthopedic department and intensive care unit of Nishtar Hospital Multan from September 2017 to November 2017. We obtained 150 consecutive pus samples from wounded patients presenting with clinical symptoms of septic wound. The collected samples were transported aseptically to the microbiology laboratory within 30 minutes and segregation was done on the basis of infection site such as knee joints, burn sites, caesarean operated sites etc. Collected samples were inoculated on blood agar and MacConkey agar. Mannitol Salt agar was used as a selective medium for isolation of Staphylococcus aureus after incubation at 37°C for 24 hours. The culture were analyzed for morphological, physiological and biochemical characteristics. For the identification of bacterial isolates samples were subjected to biochemical tests; catalase test, coagulase test and DNAse test. Data was analyzed in the form of frequency and percentage with Microsoft Excel. Results: Bacteriological investigation of septic wounds pus sample of 150 consecutive patients, in which there were 88 (58.6%) males and 62 (41.4%) females. Mean age of our patients was 28.91 ± 5.56 years, ranging from 20 – 50 years, 50 (33.33%) were aged 20 – 30 years, 40 (26.4%) were aged 31- 40 years, 28 (18.6%) were aged 41-50 years and 32 (21.1%) were above 50 years. Out of 150 pus samples, 60 (40%) had septic wound with S.aureus growth out of which methicillin sensitive Staphylococcus was 30% and MRSA was 34.6% and there 5% cases that were also resistant to vancomycin.. Two patients (4%) had fungal infections while 9 patients (18%) showed only gram negative rods and all were Catalase test negative. Source of infection was also found to be significant factor as 82 patients (55%) had poor unhygienic condition, 60 patients (40%) showed poor or improper dressing. Conclusion: In this study we observed that almost two third of the septic wounds were infected with staphylococcus aureus, which may be due to hospital acquired infections and nosocomial due to improper unhygienic condition. There is special need of strategy implementation to control hospital acquired and nosocomial infections for a healthy community. It is recommended that consultants should update their knowledge due to continuously emerging antimicrobial resistance