Antimicrobial susceptibility profile of Staphylococcus aureus isolated from pyogenic infections-Variations encountered at secondary and tertiary care level centres

Abstract

Introduction: The bacterial profile of pus samples in many studies remain the same, but the antibiotic resistance pattern of these isolates has shown a lot of variations. Objective: Comparative study of bacteriological profile and antimicrobial susceptibility of Staphylococcus aureus isolated from pus and wound swab of patients at secondary and tertiary care level centres. Material and Methods: This observational retrospective study was conducted at the department of Microbiology in a super specialty Post Graduate institute. Antibiotic sensitivity testing of Staphylococcal isolates was performed by modified Kirby Bauer’s disc diffusion method as per CLSI 2017 and EUCAST guidelines. Automated susceptibility testing was performed by Vitek-2 Compact system. Conclusions: This study provides a comparative All medical pus specimens from both institution as well as from SRCLI (State Referral Centre for Clinical Lab Investigation) were included of Staphylococcus aureus isolated from pus and wound swab of patients to formulate the local antibiotic policy to initiate the appropriate empirical antibiotic treatment at secondary and tertiary care level centres. Results: Out of 997(59.38%) samples showing single growth, Gram positive organisms were 216 (35.23%) for institutional and 195 (50.78%) for SRCLI (State Referral Centre for Clinical Lab Investigation). 85% and 91% isolates of Staphylococcus aureus were resistant to penicillin followed by erythromyc in (53.5% and 49%) and cefoperazone-sulbactum (28.5% and 14%), while 31 (55%) and 36 (34.61%) isolates were MRSA respectively for institutional and SRCLI. Even the higher antibiotic like linezolid showed 2.5% resistance (P = 0.5054) in MRSA isolates of SRCLI compared to 0% in institutional samples, which was, though not statistically significant, but is of great concern. Vancomycin showed no resistance in both areas. Keywords: Pyogenic Infections, Secondary and Tertiary Health Care, Level Centre, Antimicrobial Resistance