Biofilm Formation and Antibiotic Resistance in Methicillin Resistant Staphylococcus Aureus Among Nasal Isolates of HIV Infected Patients in A Tertiary Care Hospital

Abstract

Staphylococci are recognized as the most frequent causes of biofilm-associated infections as well as community acquired and hospital acquired infections all over the world. HIV is a well established risk factor for nasal colonization of staphylococcus aureus. MRSA is substantial cause of morbidity and mortality among HIV infected patients worldwide. Biofilm production is an important virulence factor of S. aureus which makes the organism more resistant for antimicrobials. The biofilm forming isolates have different spectrum of antibiotic sensitivity which make more therapeutic difficulties. Hence, Rapid and accurate method for detection of Methicillin resistant Staphylococcus aureus (MRSA) and Biofilm production is an important role of clinical microbiology laboratories to avoid treatment failure and to control the endemicity of MRSA. newlineA total of 440 nasal swab samples from 220 HIV positive cases and 220 HIV negative controls were processed, among which 144 isolates of S. aureus were obtained. Methicillin resistance was determined by oxacillin disc diffusion, cefoxitin disc diffusion the Oxacillin screen agar test and mecA gene detection by PCR. newlineIn this study out of 220 HIV seropositive patients, 43.64% isolates were confirmed to be S. aureus, 18.75% MRSA and 81.25% were MSSA. Similarly among HIV negative persons, prevalence of S. aureus was 21.82% among which 6.25% isolates MRSA while 93.75% were MSSA. Cefoxitin disc diffusion showed 100% specificity (95% CI; 97.05% - 100.00%), 100% sensitivity (95% CI; 83.89% -100.00%) and 100% accuracy (95% CI; 97.47% to 100.00%) while comparing with gold standard mecA gene PCR. Among the nasal carriers; males (60%) ware dominant on females (40%). Highest frequency was observed in 31-40 years age group (37%) while least was observed in 51-60 years (5%). S. aureus colonization among Cases and Controls shows no statistically significant correlation between age and carriage rate (P= 0.663; 95% C.I for EXP (B) 1.005 = 0.983- 1.028) in Binary Logistic regression analysis. But, in con