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Abstract：
Streptococcus agalactiae (Group B Streptococcus, GBS) is a major cause of neonatal infections with high morbidity and mortality, and clindamycin is the main antibiotic used to treat GBS infections in patients allergic to penicillin. We aimed to analyse the antibiotic sensitivity, sequence types, serotypes, virulence factors, and antibiotic resistance mechanisms of clinically isolated clindamycin-resistant S. agalactiae and provide basic data for the treatment, prevention, and control of clinical infection of S. agalactiae. A total of 110 strains of clindamycin-resistant S. agalactiae were collected from two tertiary hospitals in Hebei, China. We performed antibiotic sensitivity tests for 11 antibiotics on these strains and whole-genome sequencing analysis. All the strains were susceptible to penicillin, ampicillin, linezolid, vancomycin, tigecycline, and quinupristin-dalfopristin. Resistance to erythromycin, levofloxacin, tetracycline, and chloramphenicol were also observed. Genome sequence analysis revealed that all strains belonged to 12 sequence types (STs) related to six cloning complexes (CCs), namely CC10, CC19, CC23, CC651, CC1, and CC17. Five serotypes were identified, including IA, IB, II, III, and V. The most prominent resistance genes were mreA (100%) and ermB (81.8%). Furthermore, cfb, cylE, pavA and the gene cluster related to the pili were 100% present in all strains, followed by lmb (95.5%) and srr1 (67.2%). This study found that clindamycin-resistant S. agalactiae showed polymorphisms in molecular types and serotypes. Furthermore, multiple virulence factor genes have been identified in their genomes.
摘要：
无乳链球菌（B组链球菌，GBS）是新生儿感染的主要原因，发病率和死亡率高，克林霉素是用于治疗对青霉素过敏的患者的GBS感染的主要抗生素。我们的目的是分析抗生素的敏感性，序列类型,血清型,毒力因子，和临床分离的克林霉素耐药无乳链球菌的耐药机制，为治疗提供基础数据，预防,并控制无乳链球菌的临床感染。从河北省两家三甲医院共收集到110株克林霉素耐药无乳链球菌,中国。我们对这些菌株进行了11种抗生素的抗生素敏感性测试和全基因组测序分析。所有的菌株都对青霉素敏感,氨苄青霉素,利奈唑胺,万古霉素,替加环素,还有Quinupristin-dalfopristin.对红霉素的抗性，左氧氟沙星,四环素,和氯霉素也被观察到。基因组序列分析表明，所有菌株都属于与6个克隆复合物（CC）相关的12种序列类型（STs），即CC10、CC19、CC23、CC651、CC1和CC17。确定了五种血清型，包括IA,IB,II,III,和V。最突出的抗性基因是mreA(100%)和ermB(81.8%)。此外，cfb,CylE,pavA和与菌毛相关的基因簇在所有菌株中均100%存在，其次是lmb(95.5%)和srr1(67.2%)。这项研究发现，耐克林霉素无乳链球菌在分子类型和血清型中显示出多态性。此外，已在其基因组中鉴定出多种毒力因子基因。
