住院患儿肺炎链球菌血清型及耐药性分析

Serotype distribution and antibiotic resistance of Streptococcus pneumoniae in hospitalized children

目的：分析住院患儿临床标本分离出的肺炎链球菌的血清型分布和耐药状况。方法收集2012年1月至2014年3月分离自首都儿科研究所附属儿童医院住院儿童非重复肺炎链球菌103株,其中痰和支气管盥洗液标本的非侵袭性菌株82株,血液和脑脊液的侵袭性菌株21株。采用荚膜肿胀实验进行肺炎链球菌血清分型,应用E-test和纸片扩散法检测肺炎链球菌对抗生素的敏感性,PCR方法检测大环内酯类ermB和mefA基因,采用χ^2检验进行率的比较。结果82株分离自下呼吸道的非侵袭性菌株,常见血清型为19F（30．5%,25/82）,19A（14．6%,12/82）,23F（12．2%,10/82）和6A（10．9%,9/82）,7价肺炎链球菌蛋白结合疫苗（PCV7）、PCV10和 PCV13覆盖率分别为53．7%（44/82）、53．7%（44/82）和85．4%（70/82）；21株侵袭性菌株常见血清型为23F（23．8%,5/21）、14（19．0%,4/21）、6B（19．0%,4/21）、19A（9．5%,2/21）和19F（9．5%,2/21）,PCV7、PCV10和PCV13的覆盖率分别为76．1%（16/21）、81．0%（17/21）和90．5%（19/21）。非脑膜炎菌株对青霉素的敏感性为96．0%（97/101）,发现1株青霉素耐药的脑膜炎菌株。103株肺炎链球菌的多重耐药率为98．1%（101/103）。分离株均对红霉素耐药,且均携带 ermB,同时37．8%（39/103）的菌株携带mefA。结论住院患儿肺炎链球菌分离株 PCV13相对于 PCV7和 PCV10疫苗覆盖率要高,提示PCV13在预防肺炎链球菌疾病和控制多重耐药方面可发挥更好的作用。肺炎链球菌对青霉素敏感,青霉素仍可作为儿童肺炎链球菌感染性疾病临床治疗的首选药物,但对大环内酯类耐药情况严重, ermB是介导肺炎链球菌大环内酯类耐药的主要机制。（中华检验医学杂志,2015,38：622-626）

Objective To analyze the serotype and antibiotic resistance of Streptococcus pneumoniae in hospitalized children. Methods A total of 103 non-repetitive S. pneumoniae isolates were collected from children admitted to Capital Institute of Pediatrics from January 2012 to March 2014, including 82 non- invasive isolates from respiratory tract of pneumonia patients, and 21 invasive isolates from blood and eerebrospinal fluid. The serotypes of S. pneumoniae strains were identified using the capsular swelling method. E-test and K-B methods were applied to determine antimicrobial susceptibility. The ermB and mefA genes were tested by PCR. These data were analyzed by X2 test. Results Of 82 strains isolated from respiratory tract, the prevalent serotypes were 19F （30.5%, 25/82）, 19A （14.6%, 12/82）, 23F （12. 2% , 10/82） , and 6A （ 10.9% , 9/82）. The coverage rates of the PCV7, PCV10, and PCV13 vaccine were 53.7% （44/82）, 53.7% （44/82） and 85.4% （70/82）, respectively. Of 21 strains isolated from blood and eerelc）rospinal fluid, the most common serotypes were 23F （23.8% , 5/21 ）, 14（ 19.0% , 4/21 ） , 6B （19.0%, 4/21）, 19A （9.5%, 2/21）, and 19F （9.5%, 2/21）. The coverage rates of the PCV7, PCV10, and PCVl3 vaccine were 76.1% （ 16/21 ）, 81.0% （ 17/21 ） and 90.5% （ 19/21 ）, respectively. For non-meningitis isolates, the susceptibility rate to penicillin was 96.0% （97/101）. For meningitis isolates, one strain was resistant to penicillin. Multi-drug resistance was exhibited in 98. 1% （101/103） isolates. All the isolates were resistant to erythromycin. Among these strains, 100% carried the ermB gene and 37.8% （39/103） expressed both the ermB and mefA genes. Conclusions The vaccine coverage rate of PCV13 was higher than PCV7 and PCV 10, indicating that PCV13 had a better effect on preventing pneumococcal infections for children. S. pneumoniae was sensitive to penicillin, which was still the first choice of treatment for S. pneumoniae infections. All the isolates were resistant to erythromycin, and ermB was the dominant mechanism of macrolide-resistance.