Species distribution and antibiogram of coagulase negative Staphylococci isolated from various clinical specimens in a tertiary care hospital

Original Article

Author Details : Namratha W Nandihal, Uma Chikkaraddi*

Volume : 7, Issue : 3, Year : 2021

Article Page : 199-206


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Background: Coagulase Negative Staphylococci (CoNS) are common inhabitants of skin and mucous membrane, may act as pathogens causing fatal infections especially in immunocompromised patients. CoNS mainly cause infections involving biofilm on implanted biomaterials. Increase in antimicrobial resistance causes difficulties to treat life threatening infections. Despite their growing importance, their speciation is rarely done. Therefore, the present study is undertaken to identify CoNS to the species level and to know their antibiotic susceptibility pattern along with rate of MRCoNS.
Materials and Methods: 250 isolates from various clinical specimens were considered in this study. The isolates were identified by colony morphology, Gram staining, catalase, slide and tube coagulase test. Speciation was done by Novobiocin resistance, urease activity, ornithine decarboxylase, pyrrolidonylarylamidase and aerobic acid production from mannose. The antimicrobial susceptibility was performed by Kirby-Bauer’s disc diffusion method as per CLSI guidelines.
Results: Among 250 CoNS isolates, commonest species identified was S.epidermidis(59.2%) followed by S.haemolyticus(19.6%) and S.saprophyticus(12.4%). They were commonly isolated in the age group 21 to 30 years (26.8%) and among males(58%). Total of 33.2% were isolated from pus followed by blood(21.6%). Majority species expressed resistance towards nalidixic acid(97.2%) followed by Penicillin(94%), 74.4% to Amoxicillin-Clavulanic acid and 66.4% to Cotrimoxazole. All the isolates were
sensitive to Vancomycin. Methicillin resistance among CoNS was 73.2%.
Conclusion: The increased recognition of pathogenic potential in CoNS and emergence of drug resistance among them demonstrates the need to adopt simple laboratory methods to identify the species and determine the antibiotic resistant patterns to help the clinicians in treating the infections caused by CoNS.

Keywords: CoNS, MRCoNS, Speciation, S epidermidis, S haemolyticus

How to cite : Nandihal N W, Chikkaraddi U, Species distribution and antibiogram of coagulase negative Staphylococci isolated from various clinical specimens in a tertiary care hospital. IP Int J Med Microbiol Trop Dis 2021;7(3):199-206

Copyright © 2021 by author(s) and IP Int J Med Microbiol Trop Dis. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License (creativecommons.org)

Article History

Received : 14-07-2021

Accepted : 23-08-2021

Available online : 01-09-2021

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