2012-2016年天津市猩红热患儿A组链球菌病原学特征分析

Etiological characteristics of Streptococcus pyogenes isolated from children with scarlet fever in Tianjin from 2012 to 2016

目的分析天津市2012—2016年猩红热患儿A组链球菌（GAS）病原学特征。方法以2012—2016年天津市猩红热监测点医院被临床诊断为猩红热患儿为研究对象，排除标准为无法配合采样的猩红热患儿，共采集575例患儿的咽拭子。采用生化方法，对咽拭子进行细菌的分离和鉴定；采用PCR方法，对分离株进行emm基因分型和超抗原基因speA、speC检测；使用K-B纸片法测定菌株对10种抗生素的耐药性。比较不同emm基因分型GAS超抗原基因携带情况，以及所有GAS对不同抗生素耐药情况。 结果共分离得到198株GAS，检出5个emm型别，即emm1/11/12/22/89，优势型别为emm12型（52.9%，100株）和emm1型（44.4%，84株）。speA和speC基因的携带率分别为21.7%（41株）和76.7%（145株），emm1型GAS的speA基因携带率为33.3%（28株），高于emm12型[12.0%（12株）]（χ2=12.21，P〈0.001），emm1型GAS speA和speC基因同时携带率为27.4%（23株），高于emm12型[12.0%（12株）]（χ2=7.01，P=0.008）。对阿奇霉素、红霉素、克拉霉素、克林霉素、四环素、左氧氟沙星和氯霉素的耐药率分别为96.8%（183株）、96.3%（182株）、92.1%（174株）、92.1%（174株）、73.0%（138株）、2.1%（4株）和1.6%（3株），未发现对青霉素、头孢唑啉和万古霉素耐药，差异有统计学意义（χ2=953.28，P〈0.001）。结论emm12和emm1型GAS是导致天津市儿童发生猩红热的2个优势型别，其携带speA和speC基因情况不同；GAS对青霉素、头孢唑林和万古霉素敏感，对克林霉素、克拉霉素、红霉素和阿奇霉素高度耐药。

ObjectiveTo investigate the etiological characteristics of Streptococcus pyogenes that caused scarlet fever from 2012 to 2016 in Tianjin.MethodsThe subjects were children diagnosed clinically as scarlet fever in Tianjin scarlet fever monitoring hospital from 2012 to 2016. The exclusion criteria were children with scarlet fever who were unable to cooperate with sampling. A total of 575 cases of children＇s swabs were collected. Biochemical methods were used to isolate and identify the bacteria of pharynx swab, and the PCR method was used to detect the emm genotyping and superantigen speA and speC, and the resistance of the strains to 10 antibiotics was measured by K-B paper method. We compared the carrying status of superantigen genes by different types of GAS and the resistance of all GAS to different antibiotics.ResultsThere were 5 emm types （emm1/11/12/22/89）. The dominant types were emm12 （52.9%, 100 strains） and emm1 （44.4%, 84 strains）. The carrying rates of speA and speC genes were 21.7% （41 strains） and 76.7% （145 strains）, respectively. The speA gene carrying rate of emm1 type GAS was 33.3% （28 strains）, which were higher than that of emm12 （12% （12 strains）） （χ2=12.21, P〈0.001）. The speA and speC gene simultaneous carrying rate of emm1 type GAS was 27.4% （23 strains）, which was higher than that of emm12 type （12% （12 strains）） （χ2=7.01, P=0.008）. The percentages of the strains that were resistant to Azithromycin, Erythromycin, Clarithromycin, Clindamycin, Tetracyclin, Levofloxacin and Chloramphenicol were 96.8% （183 strains）, 96.3% （182 strains）, 92.1% （174 strains）, 92.1% （174 strains）, 73.0%（138 strains）, 2.1% （4 strains） and 1.6% （3 strains）, respectively. All isolates were susceptible to Penicillin, Cefazolin and Vancomycin, and there were statistical significance （χ2=953.28, P〈0.001）. ConclusionThe dominant emm types causing scarlet fever are emm12 and emm1. The frequencies of speA and speC in emm1 and emm12 are different. S.pyrogenes in Tianjin were susceptible to penicillin, cefazolin and vancomycin, but highly resistant to the clindamycin, clarithromycin, erythromycin and azithromycin.