425. Clinical and molecular changes in group A streptococcus: Over the past 22 years in Korea
Session: Poster Abstract Session: Pediatric Infections
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C
Background: Group A streptococcus (GAS) is among the most common human pathogens responsible for a wide spectrum of diseases. The incidence of GAS infections vary over time in relation with variation in the predominant emm types. Recently, the increase of GAS infections in Korea for scarlet fever was reported and we experienced an increase in severe GAS infections. 

Methods: GAS isolates previously obtained from clinical isolates at Seoul National University Children’s Hospital between 1991 and 2012 and Seoul National University Bundang Hospital between 2006 and 2012 were investigated. The clinical characteristics and antimicrobial resistance were retrospectively reviewed. The emm genotypes, pyrogenic exotoxins (SpeA, SpeB, SpeC) and macrolide resistance genes (ermB, mefA) were identified using polymerase chain reaction (PCR) and sequencing. 

Results: A total of 171 GAS isolates were investigated. Among these isolates, the clinical diagnosis were as followed; pharyngitis 51 (29.8%), scarlet fever 41 (24.0%), skin and soft tissue infections 38 (22.2%), invasive diseases 21 (12.3%), PSGN 6 (3.5%), rheumatic fever 2 (1.2%), and others 6 (3.5%). The three most prevalent emm types were emm1 (17.5%), emm4 (17.0%), and emm12 (17.0%). Among scarlet fever, 48.8% (20/21) were due to emm4 and among invasive diseases 42.8% (9/21) were due to emm1. The resistance rates of erythromycin and clindamycin were 16.7% and 16.0%, respectively. Among 27 erythromycin resistant isolates, ermB gene was detected in 8 isolates and mefA gene was in 2 isolates. SpeB was detected in all isolates and SpeA and SpeC genes were detected in 28.1% and 46.8%, respectively. A recent increase in invasive disease was seen; 57.1% (9/21) of all invasive disease were reported in the past 3 years, among those emm1 accounted for 88.9% (8/9). In 2003, emm4 was first detected in our study, and among scarlet fever isolates during 2011-2012, 91.7% (11/12) were due to emm4. Most emm4 types (89.7%) had SpeC gene.

Conclusion: The emm1 and emm4 serotype were associated with specific diseases, and there was a recent increase in invasive diseases. Changes in prevalent GAS serotypes and diversity in disease emphasizes the importance of continuous surveillance on clinical and molecular characteristics of GAS.

Jae Hong Choi, MD1, Nu Ri Yang, MD2, Hyunju Lee, MD, PhD1, Eun Young Cho, MD2, Eun Hwa Choi, MD, PhD3 and Hoan Jong Lee, MD, PhD, FIDSA3, (1)Pediatrics, Seoul National University Bundang Hospital, Seongnam, South Korea, (2)Pediatrics, Seoul National University Children's Hospital, Seoul, South Korea, (3)Department of Pediatrics, Seoul National University Children’s Hospital, Seoul, South Korea


J. H. Choi, None

N. R. Yang, None

H. Lee, None

E. Y. Cho, None

E. H. Choi, None

H. J. Lee, None

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