北京地区肺炎链球菌的耐药性及其分子流行病学调查

目的 了解北京地区肺炎链球菌的耐药性以及青霉素耐药株的分子流行病学特征。方法 １９９７年９－１１月采集北京市８所幼儿园９８５名儿童鼻咽拭子标本，分离培养肺炎链球菌，用Ｅｔｅｓｔ法和琼脂稀释法测定菌株对１２种抗生素的最低抑菌浓度，用“荚膜肿胀”技术测血清分型，燕用盒式聚合酶链反应分析青霉素耐药株的亲缘关系。

Antimicrobial resistance in Streptococcus pneumoniae in Beijing and molecular typing of penicillin-resistant strains

OBJECTIVE: To investigate antimicrobial resistance of Streptococcus pneumoniae in Beijing and molecular epidemiology of penicillin-resistant pneumococci strains. METHODS: The resistance to beta-lactam and non-beta-lactam antibiotics of 244 nasopharyngeal isolates of Streptococcus pneumoniae collected from September to November 1997 in 8 day-care centers in Beijing was studied by Etest and agar dilution method. Serotyping was done by "capsular swelling" technique. BOX-PCR technique was used to detect the DNA of resistant strains. RESULTS: 24.8% (244/985) of the children carried Streptococcus pneumoniae. The agreement between the MICs obtained by Etest and agar dilution for penicillin and ceftriaxone was > 93.7%. By Etest, 3/244 (1.3%) strains were resistant to penicillin(MICs, 3 micrograms/ml) and 32/244(13.1%) strains in termedinte (MICs, 0.094-0.25 microgram/ml). Penicillin-susceptible strains were also susceptible to the other 4 tested beta-lactams. In penicillin non-susceptible strains, 11.4% (4/35) isolates were resistant to the other beta-lactams. The resistant rates of erythromycin, tetracycline, chloramphenicol and trimethoprim-sulfamethoxazole (TMP-SMZ) were 74.0%, 87.6%, 47.8%, 63.3%, respectively. All of the strains were susceptible to vancomycin and rifampin. 119/244(48.7%) strains isolated were multiresistant to tetracycline, erythromycin and TMP/SMZ. Serotype 6A(33.6%), 19F(16.8%), 23F(15.1%), 15(11.2%), 6B(4.3%) were most common. 57.1% (20/35) penicillin non-susceptible strains were of serotype 23F and had similar or identical multiresistance and BOX patterns. CONCLUSION: In Beijing, the prevalence of penicillin-resistant pneumococci was obviously lower than that of neighboring countries, but resistant rate to non-beta-lactams was high. The epidemic multiresistant 23F clone found in day-care centers was different from the Spanish clone.