Antimicrobial susceptibility patterns and macrolide resistance genes of beta-hemolytic viridans group streptococci in a tertiary Korean hospital.
The aim of this study was to investigate antimicrobial susceptibilities and macrolide resistance mechanisms of beta-hemolytic viridans group streptococci (VGS) in a tertiary Korean hospital. Minimum inhibitory concentrations (MICs) of seven antimicrobials were determined for 103 beta-hemolytic VGS isolated from various specimens. The macrolide resistance mechanisms of erythromycin-resistant isolates were studied by the double disk test and polymerase chain reaction (PCR). The overall resistance rates of beta-hemolytic VGS were found to be 47.5% to tetracycline, 3.9% to chloramphenicol, 9.7% to erythromycin, and 6.8% to clindamycin, whereas all isolates were susceptible to penicillin G, ceftriaxone, and vancomycin. Among ten erythromycin-resistant isolates, six isolates expressed a constitutive MLS(B) (cMLS(B)) phenotype, and each of the two isolates expressed the M phenotype, and the inducible MLS(B) (iMLS(B)) phenotype. The resistance rates to erythromycin and clindamycin of beta-hemolytic VGS seemed to be lower than those of non-beta-hemolytic VGS in our hospital, although cMLSB phenotype carrying erm(B) was dominant in beta-hemolytic VGS.
Uh
Young
Y
Department of Laboratory Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea. u931018@yonsei.ac.kr
Hwang
Gyu Yel
GY
Jang
In Ho
IH
Kwon
Ohgun
O
Kim
Hyo Youl
HY
Yoon
Kap Jun
KJ
D002443:Ceftriaxone / Q000494:pharmacology; D002701:Chloramphenicol / Q000494:pharmacology; D002981:Clindamycin / Q000494:pharmacology; D003428:Cross Infection / Q000235:genetics*; D024881:Drug Resistance, Bacterial; D004917:Erythromycin / Q000494:pharmacology; D006801:Humans; D007124:Immunoenzyme Techniques; D007723:Korea; D018942:Macrolides / Q000494:pharmacology*; D010400:Penicillin G / Q000494:pharmacology; D010641:Phenotype; D016133:Polymerase Chain Reaction; D013752:Tetracycline / Q000494:pharmacology; D014640:Vancomycin / Q000494:pharmacology; D034363:Viridans Streptococci / Q000235:genetics* / Q000378:metabolism*
D018942:Macrolides; D002981:Clindamycin; D004917:Erythromycin; D002701:Chloramphenicol; D014640:Vancomycin; D002443:Ceftriaxone; D013752:Tetracycline; D010400:Penicillin G