Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia; Department of Microbiology and Immunology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.
Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia.
J Glob Antimicrob Resist. 2023 Dec;35:244-251. doi: 10.1016/j.jgar.2023.10.007. Epub 2023 Oct 14.
Group B Streptococcus (GBS) has emerged as an important cause of severe infections in adults. However, limited data are available regarding the epidemiology of GBS in Saudi Arabia.
Isolates were collected over a period of eight months from colonized (n = 104) and infected adults (n = 95). Serotypes and virulence determinants were detected by polymerase chain reactions (PCRs). Genetic relatedness was assessed using Multiple Locus Variable Number Tandem Repeat Analysis (MLVA). Antimicrobial susceptibilities were determined by disk diffusion.
Serotypes III and V (25% each) were the most prevalent, followed by serotypes II (16.18%), Ia (13.24%), VI (9.31%), and Ib (8.82%), while five isolates remained non-typeable (2.45%). Hypervirulent serotype III/CC17 clone (n = 21) accounted for 41.18% of the serotype III isolates. Most isolates (53.92%) harboured pilus island (PI) 1 and 2a types, while PI-2b was predominantly detected in the hypervirulent clone. Isolates were variably resistant to tetracycline (76.47%), erythromycin (36.76%), clindamycin (25.49%), and levofloxacin (6.37%), but remained susceptible to penicillin. Macrolide resistant isolates exhibited constitutive (55.42%) and inducible macrolide-lincosamide-streptogramin B resistance phenotypes (33.74%), while a few had L (9.64%) or M (1.2%) phenotypes. MLVA patterns of dominant serotypes III and V revealed 40 different types divided into 12 clusters and 28 singletons. Interestingly, macrolide resistance was significantly associated with two major MLVA types.
GBS isolates belonged predominantly to serotypes III and V, but there were no clear associations between serotypes and patient groups. The studied isolates exhibited high levels of resistance to erythromycin and clindamycin that need further surveillance.
B 群链球菌（GBS）已成为成人严重感染的重要病因。然而，沙特阿拉伯有关 GBS 流行病学的数据有限。
在 8 个月的时间里，从定植（n=104）和感染的成人（n=95）中采集分离株。通过聚合酶链反应（PCR）检测血清型和毒力决定因素。使用多位点可变数目串联重复分析（MLVA）评估遗传相关性。通过圆盘扩散法测定抗菌药物敏感性。
血清型 III 和 V（各占 25%）最为常见，其次是血清型 II（16.18%）、Ia（13.24%）、VI（9.31%）和 Ib（8.82%），而 5 个分离株仍无法定型（2.45%）。高毒力血清型 III/CC17 克隆（n=21）占血清型 III 分离株的 41.18%。大多数分离株（53.92%）携带菌毛岛（PI）1 和 2a 型，而 PI-2b 主要存在于高毒力克隆中。分离株对四环素（76.47%）、红霉素（36.76%）、克林霉素（25.49%）和左氧氟沙星（6.37%）的耐药性不同，但仍对青霉素敏感。大环内酯类耐药株表现出固有（55.42%）和诱导型大环内酯类-林可酰胺类-链阳性菌素 B 耐药表型（33.74%），而少数有 L（9.64%）或 M（1.2%）表型。主要血清型 III 和 V 的 MLVA 模式显示 40 种不同类型，分为 12 个簇和 28 个单倍型。有趣的是，大环内酯类耐药与两种主要 MLVA 类型显著相关。
GBS 分离株主要属于血清型 III 和 V，但血清型与患者群体之间没有明确关联。所研究的分离株对红霉素和克林霉素的耐药水平较高，需要进一步监测。
