AbstractIntroduction: Coagulase negative staphylococci (CoNS), which are the normal skin flora, have emerged as predominant pathogens in hospital-acquired infections. More than 30 species of CoNS are recognized but only a few are commonly incriminated in human infections. CoNS species identification, which is still difficult for most clinical laboratories, is necessary in order to establish epidemiological trends, confirm treatment failures and to determine the cause of specific infections. Recently use of broad-spectrum antibiotics for treatment of CoNS leads to increase in the development of antibiotic resistance. Therefore the present study was conducted to identify frequency of CoNS species isolated from various clinical specimens and determination of their antimicrobial susceptibility pattern. Material and Method: Prospective study included a total of 238 non duplicate coagulase negative staphylococci from various clinical specimens. The specimens were collected using strict aseptic precautions and transported immediately to the laboratory. All the specimens received were processed further for identification by standard microbiological procedures [17]. Qualitative data were compared with the Chi-Square or Z test as appropriate. Results: Predominant species isolated in our study was S. epidermidis (42.02%) followed by S. haemolyticus (21.43%) and S. saprophyticus (15.13%). Majority of CoNS species were isolated from pus sample with the exception of S. saprophyticus which was more commonly isolated from urine. Majority of CoNS isolates were resistant to penicillin followed trimethoprim/ sulfamethaxazole and tetracycline and all isolates were sensitive to vancomycin, teicoplanin and linezolid. In our study, 58.82% species of CoNS were methicillin resistant. Antimicrobial resistance to most of the commonly used antibiotics was more among methicillin resistant CoNS as compared to methicillin sensitive and the difference was statistically significant. Conclusion: The increased recognition of pathogenic potential of CoNS and emergence of drug resistance among them warrants the need to identify various species of CoNS and determine their antibiotic resistance pattern.
Keywords: CoNS; S. Epidermidis; S. Saprophyticus; MRCoNS.