Annals of Clinical Microbiology, The official Journal of the Korean Society of Clinical Microbiology


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pISSN 2288-0585 eISSN 2288-6850

Erythromycin Resistance Phenotype of Streptococcus pyogenes

Original article

Annals of Clinical Microbiology (Ann Clin Microbiol) 1999 December Volume 2, Issue 2, pages 131-134.

Erythromycin Resistance Phenotype of Streptococcus pyogenes

Young Uh*,** Gyu Yel Hwang*, In Ho Jang*, Jong Sun Park*, Oh-Gun Kwon*, and Kap Jun Yoon*

Department of Clinical Pathology, Yonsei University Wonju College of Medicine, Wonju*; Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Korea**


Background: The erythromycin-resistance rate and phenotype distribution of Streptococcus pyogenes are quite different by geographical variation and study period. The aim of the present study was to determine the evolution of resistance to erythromycin and the frequency of erythromycin resistance phenotype of S. pyogenes isolated from Wonju Christian Hospital.

Methods: The minimal inhibitory concentrations (MICs) of erythromycin and clindamycin for 94 S. pyogenes isolated from clinical specimens between 1990 to 1998 were investigated. Double disk test of erythromycin (78µg) and clindamycin (25µg) were performed for 15 isolates of erythromycin-resistant S. pyogenes to evaluate the erythromycin resistance phenotype.

Results: The resistance rates of 94 isolates of S. pyogenes were 16%(15/94) to erythromycin and 4%(4/94) to clindamycin. The frequency of erythromycin resistance phenotype in decreasing order were M phenotype (47%), inducible resistance phenotype (40%), and constitutive resistance phenotype (13%). Erythromycin-resistant S. pyogenes did not exist until 1993, but was isolated since 1994, and ranged from 14.0% to 24.0% during the period of 1994-1998.

Conclusions: Our finding documents the emergence of high resistance rates to erythromycin in S. pyogenes at Wonju area since 1994. The M phenotype (47%) and inducible resistance phenotype (40%) account for the majority of erythromycin-resistant S. pyogenes. (Korean J Clin Microbiol 1999;2:131-134)


Streptococcus pyogenes, Erythromycin resistance, Clindamycin resistance, Resistance phenotype