Background: Coagulase-negative staphylococci are normal commensal of human skin. They are considered as non-pathogenic and rarely reported as to cause severe infections. But their important role as pathogen and the increased incidence of infections caused by them have been recognized in recent years. The present study is undertaken to characterize and determine the antibiogram of coagulase-negative staphylococci isolated from clinical specimen submitted to Department of Microbiology Government Medical College Kottayam.

Introduction: Coagulase- negative Staphylococci are indigenous microbial flora of human skin and mucous membrane. They are usually consider as contaminants when isolated from a clinical specimens. These organisms are becoming increasingly recognized as pathogenic agents in nosocomial infections. Virulence factor is not clearly established but role of factors such as bacterial polysaccharide components are involved in attachments and persistence of bacteria in foreign materials.

Aim of the study: The study was undertaken to identify the Coagulase negative staphylococci, their speciation and to determine the antibiotic resistance pattern.

Materials and Methods: A total of 63 isolates were collected from different samples and subjected to biochemical characterization and antimicrobial screening using conventional methods. The isolates were identified to species level by VITEK 2- compact.

Results: The common isolation was Staphylococcus epidermidis. Antibiotic susceptibility testing showed maximum resistance to Penicillin and 100% sensitivity to Vancomycin and Linezolid. The increased isolation of potential CoNS to cause infection and drug resistance among them leads to adopt laboratory procedures for identification and antibiotic pattern of CoNS, which will help the clinicians in treating the infection.

Keywords: Coagulase negative staphylococci, S.epidermidis, Erythromycin.

1. Amoury, Bowman,F.O and Malm, J.R : Endocarditis associated with intracardiac prosthesis, Diagnosis, management and prophylaxis. J.Thoracic and Cardiovasc. Surg, 51:36-48,1996.
2. Bauer, Kirby, W.M.M Sherris, J.C.and Turck. M :Antibiotc susceptibitity testing by a standardized single disc method. Amer .J. Clin. Pathol. ,45:493-496 ,1966.
3. Abdulhadi Hassan AI-Mazroea ABP. Incidence and Clinical Significance of Coagulase Negative Staphylococci in Blood. J.of Taibah university Medical Sciences 2009;4(2): 137 -147.
4. Koneman EW, Allen SD Color atlas and Text book of diagnostic microbiology 5^th edition, Philadelphia, Lipppincott-Roven Publishers, 1997:547-549
5. Mackie and Mc Cartney. Practical medical Microbiology 14^th Churchill-Livingstone; Elsevier;254-256-128p
6. Kloos WE, Schleifer KH: Simplified scheme for routine identification of staphylococcus species.J Clin Microbiol 1975;1:82-86
7. Bannerman TL. Staphylococcus, Micrococus and other catalase positive cocci that grows aerobically Chapter28 In :Manual of Clinical Microbiology, 8^thed; Murray PR, Baron EJ, Jorgensen JH, Pfaller MA, Yolken RH, editors. ASM press: WashingtonDC;2003p.384
8. De paulis AN,PredariSc Five simple scheme for the species level identification of clinically significant coagulsae negative Staphylococci. J Clin Microbiol. 2003;41:1219-1224
9. Stephen Grojean, MT (ASCP), and Elliot L. Rank PhD Identifying Species f Coagulase-Negative Staphylococci using a Microtiter Plate panel. J.Laboratory Medicine.vol 16,No11, November 1985 p688 -692
10. Diekema, DJ Pfaller, Ma,Schmitz FJ. Survey of infections due to Staphlococcus species: freqecy of occurrence and antimicrobial susceptibility of isolates collected in the United states, Candada, Latin America, Europe and the Western Pacific region for the Sentry Antimicrobial Surveillance Program,1997-1999.Clin infect Dis.2001;32(2):114
11. Singh S Banerjee G Simple method for speciation of clinically significant coagulase negative Staphylococci and its antibiotic sensitivity/resistant pattern in NICU of a tertiary care centre. Bimedical research.2008:19(2)
12. Shubhra Singh, Gopa Banerjee ei al .Prevalence of MecA Gene positive coagulase negative Staphylococci in NICU of a teritiary care hospital Boomedical Research.2009;20(2):94-98.
13. Silvia Natoli, Caria Fontana et al. Characterisation of coagulase-negative staphylococcal isolates from blood with reduced susceptibility to glycopeptides and their therapeutic options.J antimicro Chemother 1992.29:459-466
14. Hamilton-Miller JM Iliffe A.1985. Antimicrobial resistance in coagulase-negative staphylococci. J .Med. Microbiol. 19:217-226.
15. Kloos WE, Bannerman TI.Update on clinical significance of coagulace negative staphylococci. Clin Microbial Rev 1994;7:117-140.

Dr Sreekumary.P.K

Additional Professor, Department of Microbiology,

Government Medical College Kottayam