Antimicrobial susceptibility and genetic diversity of Streptococcus agalactiae recovered from newborns and pregnant women in Brazil
Antimicrobial susceptibility and genetic diversity of Streptococcus agalactiae recovered from newborns and pregnant women in Brazil
复制标题
从巴西新生儿和孕妇中回收的无乳链球菌的抗菌敏感性和遗传多样性
DOI：
10.3109/00365548.2013.810814
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发表时间：
2013
影响因子：
--
通讯作者：
R. Barros
中科院分区：
文献类型：
--
作者：
Viviane C Souza;Fabíola C. O. Kegele;S. R. Souza;F. Neves;G. R. de Paula;R. Barros
摘要背景：已知无乳链球菌是新生儿感染的主要原因，也可引起妊娠期并发症。方法：对新生儿（18株）和孕妇（88株）临床标本中分离的106株无乳链球菌进行药敏试验，并对大环内酯类药物耐药的遗传决定因素、荚膜类型和毒力因素进行研究。采用脉冲场凝胶电泳（PFGE）分析遗传多样性。结果：菌株对头孢曲松、左氧氟沙星、青霉素G和万古霉素敏感，对四环素（85.8%）和红霉素（4.7%）耐药。红霉素耐药菌株表现为iMLSB表型，携带ermA基因，与PFGE关系密切。bac和bca基因的频率均较低。PFGE分析获得了35株菌株的11个DNA限制性内切谱。主要克隆群为A，主要由荚膜型菌株组成。克隆组B主要由荚膜V型菌株组成，包括所有红霉素耐药菌株。结论：虽然已经观察到低水平的红霉素耐药，但这是一个值得关注的事实，因为这种表型也会导致对克林霉素耐药，克林霉素是一种分娩时预防的替代药物。尽管荚膜类型多样，但Ia和V是最常见的，并且与不同的克隆群显著相关。在少数情况下，不同的荚膜类型聚集在一个克隆群中，这可能与荚膜切换有关。
Abstract Background: Streptococcus agalactiae is known to be the major cause of neonatal infections and also causes complications during pregnancy. Methods: One hundred and six strains of Streptococcus agalactiae recovered from clinical specimens of newborns (n = 18) and pregnant women (n = 88) were submitted to antimicrobial susceptibility testing and investigation of genetic determinants of macrolide resistance, capsular type, and virulence factors. Genetic diversity was evaluated by pulsed-field gel electrophoresis (PFGE) analysis. Results: Strains were susceptible to ceftriaxone, levofloxacin, penicillin G, and vancomycin and resistant to tetracycline (85.8%) and erythromycin (4.7%). Erythromycin-resistant strains presented iMLSB phenotype, harbored the ermA gene, and were closely related by PFGE. Both bac and bca genes were found in low frequencies. PFGE analysis yielded 11 DNA restriction profiles among 35 selected isolates. The major clonal group, designated as A, was composed predominantly of strains belonging to capsular type Ia. Clonal group B was composed predominantly of strains with capsular type V, including all erythromycin-resistant isolates. Conclusions: Although low levels of erythromycin resistance have been observed, this is a fact of concern because this phenotype also confers resistance to clindamycin, an alternative agent for intrapartum prophylaxis. Despite the diversity of capsular types, Ia and V were among the most common and were significantly associated with distinct clonal groups. In a few cases, different capsular types were clustered into a single clonal group, which may be related to capsular switching.
DOI：
10.1037/e548432006-001
发表时间：
2010
期刊：
MMWR. Recommendations and reports : Morbidity and mortality weekly report. Recommendations and reports
影响因子：
--
作者：
J. Verani;Lesley McGee;S. Schrag
通讯作者：
J. Verani;Lesley McGee;S. Schrag