Molecular Genetic Characterization of Clinical Isolates of Streptococcus pyogenes

Song, Ae Sook; Song, Ki Joon

Abstract

BACKGROUND
Group A streptococcus (Streptococcus pyogenes) is the most common cause of bacterial pharyngitis and an important cause of a variety of suppurative and nonsuppurative diseases. The molecular genetic analysis of group A streptococci in clinical isolates is rarely reported in Korea. In this study, molecular genetic analysis using serotyping and emm sequence analysis, testing the presence of the SpeA and SpeB gene, and the determination of an antimicrobial resistance pattern were investigated. METHODS: Sixty nine strains of S. pyogenes from clinical isolates in Korea during 1999-2002 were examined by T agglutination, serum opacity reaction, and emm sequence analysis. Also investigated were antimicrobial susceptibility and the frequency of SpeA and SpeB genes. RESULTS: The antibiotic resistance rates for S. pyogenes isolates were shown at 28.9% of erythromycin, 14.2% of ampicillin, 9.5% of chloramphenicol, and 6.3% of levofloxacin. However, all strains were susceptible to penicillin, vancomycin, and teicoplanin. By T agglutination typing, forty-one (59.4%) among sixty-nine isolates were identified as T28 (13%), T6 (13%), T1 (10%), T12 (8.7%), T4 (4%), T5/27/44 (4%), T3/B3264 (2.9%), T11/12 (1.4%), and TB3264 (1.4%). Thirty-five (50.7%) among sixty nine isolates were positive in serum opacity reaction. The SpeB gene showed positive in all strains but the SpeA gene in eleven (15.9%) strains. By emm gene sequence analysis, forty-seven (68.1%) CONCLUSIONS: Our data showed that antimicrobial resistance of clinical isolates to erythromycin were higher than those reported from the United States and Europe, and emm genotyping could be used for a reliable and efficient typing method.