Analysis of antimicrobial resistancemonitor of gram-positive cocci in vitro

Objective To discuss the distributions and drug resistance of gram-positive cocci and provide scientific basis for reasonable use of antimicrobial drugs.Methods One hundred and twenty-five strains were isolated and cultured in our department from January 2009 to December 2011.The drug susceptibility was tested by K-B method and the results were judged by the criteria guideline of CLSI 2009.Results The main strains of separated cocci were Staphylococcus aureus (68,54.4％),Enterococcus faecium (22,17.6％),coagulase-negative staphylococcus (CNS) (20,16.0％),Enterococcus faecalis (6,4.8％),Staphylococcus haemolyticus(7,5.6％)and other gram-positive cocci (2,1.6％).Methicillin-resistant S.aureus (MRSA) and Methicillin-susceptible S.aureus (MSSA) detected were 40 and 28 strains(accounted for 58.8％ and 41.1％ of S.aureaus).The results of drug susceptibility tests showed that the drug resistant rate of MRSA to Gentamicin,Clidamycin,Erythromycin and Ciprofloxacin was up to 87.5％-95.0％,and the drug resistant rate of coagulasenegative staphylococcus to Penicillin,Erythromycin,Clidamycin and Gentamicin was up to 65.0％-95.0％,besides,the drug resistant rate of E.faecalis and E.faecium to Erythromycin,high level Gentamicin and Ciprofloxacin were 86.4％-100％ and 50.0％-66.7％,respectively.No strains with drug resistant to Vancomycin,Teicoplanin and Linezolid were detected.Conclusion S.aureus was the main strains of nosocomial infection of gram cocci.The resistance of gram-positive cocci is severe,so clinicians should attaches great importance to high drug resistance of gram-positive cocci. Key words: Nosocomial infection;  Gram-positive cocci;  Distribution;  Drug resistance