唐山地区高龄孕妇携带的无乳链球菌药物敏感性和分子特征研究

Antimicrobial susceptibility and molecular characterization of Streptococcus agalactiae in pregnant women with advanced maternal age in Tangshan City

摘要:

目的 分析唐山地区高龄孕妇携带的无乳链球菌药物敏感性、分子型别、血清型别、毒力因子和耐药机制,为无乳链球菌相关感染的治疗和防控提供基础数据。方法 从华北理工大学附属医院和唐山市妇幼保健院收集42株高龄孕妇携带的无乳链球菌,进行13种抗菌药物的药物敏感性检测和基因组序列测定。结果 对四环素、红霉素、左氧氟沙星和氯霉素同时耐药的菌株占比达7.1%,35.7%的菌株呈现对红霉素、克林霉素和左氧氟沙星的多重耐药。耐药基因ermB、tetM的携带率分别为66.7%、 47.6%,29株菌(69.0%)同时发生了gyrA和parC氟喹诺酮耐药决定簇的基因突变。42株无乳链球菌属于4种血清型, 分别为ⅠB(35.7%)、Ⅲ(33.3%)、Ⅴ(26.2%)、ⅠA(4.8%);分属11个序列型(STs),占比最多的为ST10(35.7%)和ST19(31.0%);分属6个克隆复合体(CCs),其中占比最多的为CC19(42.9%)和CC12(35.7%)。所有无乳链球菌均携带毒力因子编码基因cfb、cylE和pavA。结论 唐山地区高龄孕妇携带的无乳链球菌分子型别、血清型别呈现多态性,多重耐药特征明显,携带多种类型的耐药基因和毒力基因。

Abstract:

Objective To analyze the antimicrobial susceptibility, molecular types, serotypes, virulence factors and resistance mechanisms of Streptococcus agalactiae (S. agalactiae) isolated from pregnant women with advanced maternal age in Tangshan City, and provide basic data for the treatment, prevention and control of S. agalactiae infection. Methods 42 strains of S. agalactiae isolated from pregnant women with advanced maternal age in North China University of Science and Technology Affiliated Hospital as well as Tangshan Maternal and Child Health Hospital were collected. Detection of antimicrobial susceptibility and whole genome sequencing of 13 antimicrobial agents were performed. Results The percentage of tetracycline, erythromycin, levofloxacin, and chloramphenicol concurrently resistant strains was 7.1%, 35.7% of the strains presented multidrug resistance to erythromycin, clindamycin, and levofloxacin. The carriage rates of resistance genes ermB and tetM were 66.7% and 47.6%, respectively. 29 strains (69.0%) exhibited mutations in both gyrA and parC fluoroquinolone resistance determinants. 42 strains of S. agalactiae belonged to 4 serotypes, namely ⅠB (35.7%), Ⅲ (33.3%), Ⅴ (26.2%), and ⅠA (4.8%); and 11 sequence types (STs), with the highest proportion being ST10 (35.7%) and ST19 (31.0%); as well as 6 clonal complexes (CCs), among which CC19 (42.9%) and CC12 (35.7%) had the highest proportion. All S. agalactiae carried virulence factor-encoding genes of cfb, cylE, and pavA. Conclusion The molecular types and serotypes of S. agalactiae carried by pregnant women with advanced maternal age in Tangshan City pre-sent polymorphism, with obvious multidrug resistance, and carry multiple types of drug resistance genes and virulence genes.