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Volume 38, Number 2, April 2005

Clinical and genetic analysis of invasive and non-invasive group A streptococcal infections in central Taiwan

Chia-Hui Kao, Po-Yen Chen, Fang-Liang Huang, Chih-Wei Chen, Ching-Shiang Chi, Yu-Hui Lin, Chi-Yen Shih, Bor-Shen Hu, Chia-Ro Li, Jui-Shan Ma, Yeu-Jun Lau, Kun-Chia Lu, Hsiu-Wen Yu
Department of Pediatrics, Tungs' Taichung MetroHarbor Hospital, Taichung; Department of Pediatrics and Section of Infectious Diseases, Department of Medicine, Taichung Veterans General Hospital, Taichung; Section of Infectious Diseases, Show-Chwan Memorial Hospital, Changhua; and Department of Pediatrics, Chen Ching Hospital, Taiwan

Received: July 10, 2004    Revised: September 8, 2004    Accepted: October 18, 2004   


Corresponding author:

Dr. Po-Yen Chen, Department of Pediatrics, Taichung Veterans General Hospital, 160, Section 3, Chung-Kang Road, Taichung 407, Taiwan. E-mail: This e-mail address is being protected from spam bots, you need JavaScript enabled to view it




To evaluate the clinical, bacteriologic, and genetic relatedness between invasive and non-invasive infections caused by group A Streptococcus (GAS), we retrospectively analyzed the GAS isolates in our hospital from the past decade. A total of 70 GAS-infected cases were enrolled in our study from the period 1993 to 2002. Twenty one cases had invasive disease, and 49 were non-invasive. Their medical records were reviewed, and demographic data were collected for analysis. Antimicrobial susceptibility testing was conducted according to the National Committee for Clinical Laboratory Standards for Streptococcus spp. Isolates were subjected to chromosomal SmaI (Invitrogen) digestion of pulsed-field gel electrophoresis (PFGE), and emm typing was also performed. The mean age of the invasive group was 41.1 ± 22.4 years compared with 13.0 ± 16.6 years for the non-invasive group (p<0.05). Eighty one percent of the invasive group had underlying diseases. Diabetes and malignancy were the 2 most common medical conditions. All isolates were susceptible to penicillin. The resistance rate was 42.8% and 55.1% for erythromycin in the invasive and non-invasive groups, respectively. A total of 51 different PFGE types were identified among the GAS isolates without particular genotypes. Serotype M12 was the most common one (28.4%), followed by M4 (19.4%). Our study demonstrated that the patients in the invasive group were older, with more underlying diseases, and with a higher mortality rate. Antimicrobial susceptibility of the isolates was the same in both groups. There was no epidemic strain, nor did PFGE reveal a more invasive clone.



Key words:

Bacterial drug resistance, group A Streptococcus, risk factors, serotyping, streptococcal M protein



J Microbiol Immunol Infect 2005;38:105-111.