J Korean Med Sci.  2007 Oct;22(5):791-794. 10.3346/jkms.2007.22.5.791.

Antimicrobial Susceptibility Patterns and Macrolide Resistance Genes of beta-Hemolytic Viridans Group Streptococci in a Tertiary Korean Hospital

• Uh Y
• Hwang GY
• Jang IH
• Kwon O
• Kim HY
• Yoon KJ

• KMID: 1713282
• DOI: http://doi.org/10.3346/jkms.2007.22.5.791

Abstract

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 MLSB (cMLSB) phenotype, and each of the two isolates expressed the M phenotype, and the inducible MLSB (iMLSB) 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.

Keyword

Streptococcus; erm(B); mef(A); Macrolides; Drug Resistance

MeSH Terms

Ceftriaxone/pharmacology
Chloramphenicol/pharmacology
Clindamycin/pharmacology
Cross Infection/*genetics
*Drug Resistance, Bacterial
Erythromycin/pharmacology
Humans
Immunoenzyme Techniques
Korea
Macrolides/*pharmacology
Penicillin G/pharmacology
Phenotype
Polymerase Chain Reaction
Tetracycline/pharmacology
Vancomycin/pharmacology
Viridans Streptococci/*genetics/*metabolism

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