title: Species distribution and antimicrobial resistance pattern of Coagulase-negative Staphylococci at a tertiary care centre.
abstract: BACKGROUND
  Coagulase-negative Staphylococci (CoNS), previously dismissed at contaminants, have now emerged as an important cause of nosocomial infections especially in patients with implants and prosthetic devices. They are a well-known cause of bloodstream infections, urinary tract infections, wound infections, prosthetic valve endocarditis and eye infections. This study was conducted with an aim to identify CoNS at the species level from various clinical samples and determine the antimicrobial resistance pattern of these isolates.
  
  
  METHODS
  This cross sectional study was carried out from September 2011 to February 2014 in which 150 non-repetitive clinical isolates of CoNS were identified at the species level by conventional phenotypic methods. Complete antimicrobial susceptibility profile was also determined by Kirby Bauer disc diffusion method. Susceptibility testing to vancomycin was done by E-test method.
  
  
  RESULTS
  Only three species of CoNS were isolated, the most common being Staphylococcusepidermidis (60%) followed by Staphylococcussaprophyticus (27.3%) and Staphylococcushemolyticus (12.7%). Most S. epidermidis were isolated from blood and intravascular catheter tip samples, whereas all S. saprophyticus were isolated from urine samples of female patients. All isolates were found to be resistant to penicillin, but were susceptible to glycopeptides and linezolid and showed variable resistance to fluoroquinolones, aminoglycosides and macrolides.
  
  
  CONCLUSIONS
  CoNS are emerging nosocomial pathogens and should not always be overlooked as contaminants. However, growth of CoNS from blood cultures and intravascular catheter tips should be clinically correlated and carefully interpreted. As many CoNS strains exhibit drug resistance, antimicrobial susceptibility profile should be determined prior to treatment of these infections.
authors.affiliation: Graded Specialist (Microbiology), Command Hospital (Southern Command), Pune 411040, India.
authors.forename: Puneet
authors.initials: P
authors.lastname: Bhatt
authors.affiliation: Graded Specialist (Microbiology), DRDE, Gwalior, India.
authors.forename: Kundan
authors.initials: K
authors.lastname: Tandel
authors.affiliation: Resident, Dept of Microbiology, Armed Forces Medical College, Pune 411040, India.
authors.forename: Alina
authors.initials: A
authors.lastname: Singh
authors.affiliation: Resident, Dept of Microbiology, Armed Forces Medical College, Pune 411040, India.
authors.forename: M
authors.initials: M
authors.lastname: Mugunthan
authors.affiliation: Professor, Dept of Microbiology, Armed Forces Medical College, Pune 411040, India.
authors.forename: Naveen
authors.initials: N
authors.lastname: Grover
authors.affiliation: Commandant, 174 Military Hospital, C/O 56 APO, India.
authors.forename: A K
authors.initials: AK
authors.lastname: Sahni
keywords: Coagulase-negative Staphylococci (CoNS); E-test; Kirby Bauer disc diffusion method