Microbiological and Biochemical Analysis of Methicillin-resistant Staphylococcus aureus Isolated from Patients Admitted in RIMS, Ranchi

Abstract

Background: Since methicillin-resistant Staphylococcus aureus strains are resistant to multiple antibiotics, there is a possibility of extensive outbreaks which may be difficult to control. Early detection of methicillin-resistant Staphylococcus is important from patients and hospitals point of view. Materials and Methods: The present study was carried out in the Department of Microbiology, Rajendra Institute of Medical Sciences, Ranchi, clinical isolates of methicillin-resistant S. aureus strains were obtained from admitted patients of Rajendra Institute of Medical Sciences, Ranchi. The sources of isolate included pus from infected surgical wounds, infected burn wounds, conjunctival swab, aural swab, throat swab, vaginal swab, and urine for microbiological and biochemical analysis of methicillin-resistant S. aureus. Results: All the 264 cases of staphylococcal species isolated from different clinical specimens were subjected to coagulase test. It was observed that out of 264 strains of staphylococci isolated from different sites, 165 strains (62.5%) were coagulase positive and 99 strains (37.5%) were coagulase negative by tube method. Out of the 165 strains of coagulase-positive staphylococci, maximum isolation was obtained from pus 74 followed by throat swab 55, aural swab 21, vaginal 4, conjunctival swab 9, and urine 2. All the 165 cases of coagulase-positive Staphylococcus isolated from different clinical specimens were studied for hemolysis, mannitol fermentation, pigment production, and phosphatase production. Out of these 165 strains, 162 (98%) strains produced β-hemolysis on blood agar medium. Pigment production was noted in 160 (97%) of cases. Majority of strains produced characteristic golden yellow pigment on nutrient agar plate. A total of 155 (94%) strains of staphylococci fermented mannitol with the production of acid only. Phosphatase production was observed in 157 (95%) strains of pathogenic staphylococci. Conclusion: Considering the above-mentioned pathogenicity test, it was observed that coagulase test was the single most reliable test, though coagulase-negative staphylococci are sometimes pathogenic too.