Wang Xiaolin, Cao Xuelian, Li Shunming, Ou Qianting, Lin Dongxin, Yao Zhenjiang, Chen Sidong, Wu Chuan'an, Wen Guoming, Ye Xiaohua
Laboratory of Molecular Epidemiology, School of Public Health, Guangdong Pharmaceutical University, Guangzhou, China.
Women Health Care, Maternal and Child Healthcare Hospital of Longhua District, Shenzhen, China.
Res Microbiol. 2018 Feb-Mar;169(2):101-107. doi: 10.1016/j.resmic.2017.12.004. Epub 2018 Jan 31.
Streptococcus agalactiae (GBS) remains a major cause of invasive infections in neonates and pregnant women. Our aim was to evaluate the phenotypic and molecular characteristics of GBS isolates in order to reveal potential relationships among molecular characteristics and differences in genotype-phenotype characteristics between ST17 and ST19. A total of 104 GBS isolates were collected from pregnant women. All isolates were tested for antibiotic susceptibility by disk diffusion method and molecular characteristics, including antibiotic-resistant genes, virulence genes, serotypes and STs. The prevalence of GBS colonization in pregnant women was 4.9%. All isolates were susceptible to penicillin, but a high prevalence of resistance was observed for tetracycline (76.9%) and erythromycin (72.1%), with the predominant resistant genes being tet(M), tet(O), erm(B) and mef (A/E). The most frequent serotypes were III, Ia and V, and the predominant STs were ST19, ST17, ST12, ST10 and ST651. A potential correlation existed between STs, serotypes and alp genes, with ST19/III/rib and ST17/III/rib as the most prevalent clones. Notably, we observed significant differences in phenotypic and genotypic characteristics between ST17 [levofloxacin-susceptible and tet(O)-positive] and ST19 [levofloxacin-resistant and tet(O)-negative]. Our findings reveal a high prevalence of ST19/III and ST17/III and significant characteristic differences between them.
无乳链球菌（GBS）仍然是新生儿和孕妇侵袭性感染的主要原因。我们的目的是评估GBS分离株的表型和分子特征，以揭示分子特征之间的潜在关系以及ST17和ST19之间基因型-表型特征的差异。从孕妇中总共收集了104株GBS分离株。所有分离株均通过纸片扩散法检测抗生素敏感性以及分子特征，包括耐药基因、毒力基因、血清型和序列型。孕妇GBS定植的患病率为4.9%。所有分离株对青霉素敏感，但四环素（76.9%）和红霉素（72.1%）的耐药率较高，主要耐药基因是tet(M)、tet(O)、erm(B)和mef(A/E)。最常见的血清型是III、Ia和V，主要的序列型是ST19、ST17、ST12、ST10和ST651。序列型、血清型和alp基因之间存在潜在相关性，ST19/III/rib和ST17/III/rib是最常见的克隆。值得注意的是，我们观察到ST17[左氧氟沙星敏感且tet(O)阳性]和ST19[左氧氟沙星耐药且tet(O)阴性]在表型和基因型特征上存在显著差异。我们的研究结果揭示了ST19/III和ST17/III的高患病率以及它们之间的显著特征差异。
