Article in Japanese

Multicenter analysis of pharyngotonsillitis caused by group A hemolytic streptococci: Therapeutic effect of oral β-lactam antibiotics and features of the agents

Takeshi TAJIMA¹⁾, Takeaki WAJIMA²⁾, Satoshi KOYAMA¹⁾, Satoshi IWATA³⁾, Kimiko UBUKATA³⁾, GAS surveillance study group

In order to clarify the therapeutic effects of oral β-lactam antibiotics for pharyngotonsillitis caused by group A hemolytic streptococci (GAS) and the epidemiological features of the agents, the "GAS surveillance study group" was organized by the active participation of pediatricians at the clinic of this study. Pharyngeal swab samples before and after administration of the therapeutic agent were collected from 434 patients with pharyngotonsillitis between April and October, 2012. GAS strains were isolated from a total of 360 (82.9%) of them by combining culture and PCR. Molecular emm typing showed that the most frequent type was emm1 (26.1%), followed by emm12 (23.6%), emm28 (16.3%), and emm89 (15.2%). GAS isolates, as the causative agent, have had significant changes epidemiologically in recent years. No strains with β-lactam resistance have been identified in contrast to macrolide-resistant strains at a high percentage among prevalent emm type strains. Amoxicillin, cefdinir, and cefditoren of the representative oral β-lactams have been used for all cases as the therapeutic agent. There were no significant differences in clinical efficacy by type of antibiotics and dosing conditions (twice or three times daily). However, the effectiveness of oral cephalosporins was slightly lower with administration twice daily than with administration three times a day.
Based on the above findings, surveillance based on molecular epidemiology and antimicrobial susceptibility of GAS is necessary for selecting the best therapeutical agent, in addition to giving further consideration to the dosing conditions during the treatment of pharyngotonsillitis.

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1) Department of Pediatrics, Hakujikai Memorial Hospital
2) Department of Microbiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences
3) Department of Infectious Diseases, Keio University School of Medicine

Key words
Received	October 15, 2013
Accepted	January 23, 2014

26 (1)：31─40,2014