Bacterial and Antimicrobial Susceptibility Profile of Skin and Soft Tissue Infections among Patients Attending the Tertiary Health Care Set Up

Introduction: Skin and soft tissue infections (SSTIs) have variable etiology and clinical presentation. Emergence and spread of antibiotic resistance in organisms causing skin and soft tissue infections is posing a great therapeutic challenge. It is important to monitor the changing trends in bacterial infection and their antimicrobial susceptibility pattern to provide appropriate antimicrobial therapy for controlling infection, preventing morbidity and improve the quality of life. Aims: To determine the bacterial etiology and their antimicrobial susceptibility pattern of soft tissue infections among patients attending the tertiary care set up. Materials and Methods: Pus samples received in the Department of Microbiology were included in the study. Isolation and identification were done as per standard laboratory protocol. Antimicrobial susceptibility test was done as per CLSI guidelines to determine the various resistance mechanism such as Methicillin-resistance in S. aureus, HLAR in Enterococcus spp. and ESBL production in Escherichia coli and Klebsiella spp. Results: Out of 1672 pus samples received, 1088 (65.1%) bacterial isolates were obtained. 674 (61.9%) were Gram-negative bacteria, 398 (36.6%) were Gram-positive bacteria and 16 (1.6%) were gram positive bacilli. Escherichia coli (26.6%) was the commonest isolate followed by S. aureus (13.1%) and coagulase-negative staphylococcus (CoNS) (13%). Methicillin resistance in S. aureus was found to be 36.6% and ESBL production was found in 162 (55.9%) Escherichia coli isolates and 22 (40.7%) Klebsiella spp. High level aminoglycoside resistance was observed in 15% enterococci. Gram-positive organisms showed maximum susceptibility to vancomycin and linezolid. Gram-negative bacilli especially members of Enterobacteriaceae were highly resistant to ampicillin, amoxicillin-clavulanate. Piperacillin-tazobactam combination and carbapenems showed best activity for gram negative bacilli. Conclusion: Continuous monitoring of antimicrobial susceptibility pattern in individual settings together with their judicious use is emphasized to minimize emergence of drug resistant bacteria.