中国西部某二级医院呼吸道感染住院患儿鼻咽部肺炎链球菌中常见非PCV13血清型菌株的横断面调查

The non-PCV13 serotypes were frequent among Streptococcus pneumoniae isolated from nasopharyngeal samples of hospitalized children with respiratory infection in a grade two hospital in western China

目的了解四川省中江县呼吸道感染住院患儿鼻咽部肺炎链球菌的定植状况及分离株的血清型分布和耐药性。方法 2015年1至12月采集四川省中江县人民医院儿科病房住院1月龄至14岁呼吸道感染患儿的鼻咽拭子并分离肺炎链球菌。用荚膜肿胀试验检测血清型,评估13价肺炎链球菌结合疫苗(PCV13)覆盖率。基于血清型随机选取约50%的菌株采用E-test法或纸片扩散法检测青霉素等16种抗生素的敏感性。结果共采集到1 082例鼻咽拭子,分离到肺炎链球菌199株,携带率18.4%。常见血清型为19F(14.6%)、19A(10.6%)、34(10.1%)、6A(9.0%)、23F(7.5%)、6B(7.5%)和23A型(7.0%)。PCV13覆盖率为54.8%。分离株对静脉青霉素敏感,但对口服青霉素敏感率仅为9.1%,对阿莫西林-克拉维酸敏感率为97%,对头孢曲松、万古霉素、左氧氟沙星和利奈唑胺敏感率100%,对红霉素和阿奇霉素均耐药。结论四川省中江县呼吸道感染患儿鼻咽部常有肺炎链球菌定植;分离株中非PCV13型别常见,以34和23A型为多,有必要加强监测;分离株对口服青霉素和红霉素等耐药率高,但对静脉青霉素、头孢曲松和万古霉素等普遍敏感。

ObjectiveTo investigate the carriage rate, serotype distribution and antibiotic resistance profiles of Streptococcus neumoniae （S.pneumoniae） among hospitalized children with respiratory tract infections in grade two hospital in Zhongjiang County, Sichuan and to determine the epidemiological characters of these S.pneumoniae isolates.MethodsNasopharyngeal swabs of hospitalized children with respiratory tract infections aged from 1 month to 14 years were collected from January to December 2015 at the Zhongjiang County Hospital, and S.pneumoniae was cultured.The serotypes were detected by capsule swelling experiment to assess the coverage rate of 13-valent pneumococcal conjugate vaccine （PCV13）.The sensitivity against 16 antimicrobial agents were detected by E-test or disk diffusion method for approximately half of S.pneumoniae isolates randomly selected based on the serotypes.ResultsThe nasopharyngeal carriage rate of S.pneumoniae was 18.4% （199/1082）.The common serotypes were 19F （14.6%）, 19A （10.6%）, 34 （10.1%）, 6A （9.0%）, 23F （7.5%）, 6B （7.5%） and 23A（7.0%）.The coverage rate of PCV13 was 54.8%.The proportion of non-PCV13 types was up to 45.2%.All of the isolates were sensitive to penicillin using the parenteral breakpoints, but the sensitive rate decreased to 9.1% for the oral penicillin breakpoints.The sensitivity rate of amoxycillin/clavulanate was 97%.All of the isolates were sensitive to ceftriaxone, vancomycin, levofloxacin and linezolid.However, all of the isolates were resistant to erythromycin and azithromycin.ConclusionColonization of S.pneumoniae was frequent in the nasopharynx of children with respiratory tract infections in Zhongjiang.About half of the S.pneumoniae isolates were identified as the PCV13 types.Non-PCV13 serotypes were common in the county, in which type 34 and 23A were frequent, which should be monitored for long time and in wider range.The isolates showed a high resistance to oral penicillin and erythromycin, but sensitive to parenteral penicillin, ceftriaxone and vancomycin.