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目的了解苏州地区儿童肺炎链球菌(Streptococcuspneumoniae,Sp)临床分离株青霉素、红霉素耐药的状况。方法对呼吸道感染患儿痰标本中分离到的26株Sp进行青霉素、头孢呋辛、头孢曲松、头孢噻肟、红霉素E test药敏试验,和与青霉素、红霉素耐药相关的pbp2B、ermB、ermA/B、mefA基因PCR检测,测得pbp2B基因产物进行测序并与SpR6株(青霉素敏感株,登录号:NC003098)序列比较。结果(1)pbp2B基因突变15株(58%),均为点突变,突变类型有A型11株(73%)、B型2株(13%)、C型1株(7%)、D型1株(7%);(2)11株无突变菌中青霉素、头孢呋辛、头孢曲松、头孢噻肟敏感株分别为9株(82%)、10株(91%)、11株(100%)、11株(100%);15株突变菌中青霉素、头孢呋辛、头孢曲松、头孢噻肟不敏感株分别为13株(87%)、11株(73%)、1株(7%)、1株(7%);11株A型突变株对青霉素均不敏感,10株对二代头孢不敏感;(3)ermB基因阳性9株(35%)、ermA/B基因阳性16株(62%)、mefA基因阳性7株(27%)、erm或(和)mef基因阳性21株(81%);(4)erm或(和)mef基因阳性株红霉素最低抑菌浓度为2～>256mg/L。结论pbp2B基因突变是本地区Sp青霉素耐药机制的主要遗传学基础之一;突变株中,A类突变率最高,表现对青霉素、二代头孢不敏感;ermA、ermB和mefA3种红霉素耐药基因单独或共同表达?
Objective To investigate the drug-resistant status of penicillin and erythromycin in children with Streptococcus pneumoniae (Sp) in Suzhou area. Methods 26 strains of Sp isolated from children with respiratory tract infection were tested for susceptibility to penicillin, cefuroxime, ceftriaxone, cefotaxime and erythromycin E test and to penicillin and erythromycin resistance pbp2B, ermB, ermA / B and mefA gene. PCR products of pbp2B gene were sequenced and compared with that of SpR6 (penicillin sensitive strain, accession number NC003098). Results (1) 15 (58%) pbp2B mutations were point mutations. The mutations were found in 11 strains of type A (73%), 2 strains of type B (13%) and 1 type of C (1% (2) 11 strains of non-mutants penicillin, cefuroxime, ceftriaxone, cefotaxime susceptible strains were 9 strains (82%), 10 strains (91%), 11 strains (100%) and 11 strains (100%). Among the 15 strains, 13 strains (87%) and 11 strains (73%) were insensitive to penicillin, cefuroxime, ceftriaxone and cefotaxime, respectively 11 strains were not sensitive to penicillin and 10 were insensitive to second generation cephalosporins. (3) The positive rate of ermB gene was 9 (35%), ermA / B 16 (62%) were positive for gene, 7 were positive for mefA gene (27%), 21 were positive for erm or mef gene (81%), (4) were the lowest in erythromycin Bacteriostatic concentration of 2 ~> 256mg / L. Conclusion The mutation of pbp2B gene is one of the major genetic bases of penicillin resistance in this region. Among the mutants, the mutation rate of type A is the highest, which is not sensitive to penicillin and second generation cephalosporins. The ermA, ermB and mefA3 erythromycin Drug gene alone or together?