Hawassa University College of Medicine and Health Sciences, School of Medical laboratory Science, Hawassa, Ethiopia.
Department of Microbiology, Immunology and Parasitology, Addis Ababa University College of Health Science, Addis Ababa, Ethiopia.
BMC Infect Dis. 2020 Nov 16;20(1):848. doi: 10.1186/s12879-020-05581-8.
Streptococcus agalactiae (Group B Streptococcus, GBS) serotypes, sequence types, and antimicrobial resistance profile vary across different geographic locations affecting disease patterns in newborns. These differences are important considerations for vaccine development efforts and data from large countries in Africa is limited. The aim of this study was to determine serotypes and genotypes of GBS isolates from pregnant women and their newborns in Ethiopia.
A hospital based cross-sectional study was conducted at three hospitals in Ethiopia from June 2014 to September 2015. Out of 225 GBS isolates, 121 GBS were recovered, confirmed and characterized at CDC's Streptococcus Laboratory using conventional microbiology methods and whole genome sequencing.
Of the 121 isolates, 87 were from rectovaginal samples of pregnant women, 32 from different body parts of their newborns and 2 from blood of newborns with suspected sepsis. There were 25 mother-infant pairs and 24 pairs had concordant strains. The most prevalent serotypes among mothers and/or their babies were II, Ia and V (41.5, 20.6, 19.5 and 40.6%, 25 and 15.6%, respectively). Multilocus sequence typing (MLST) on 83 isolates showed ST10 (24; 28.9%) and ST2 (12; 14.5%) as most predominant sequence types. All GBS strains were susceptible to penicillin, cefotaxime and vancomycin, which correlated to the presence of wildtype PBP2x types and the lack of known vancomycin-resistance genes. Tetracycline resistance was high (73; 88%, associated primarily with tetM, but also tetO and tetL). Five isolates (6%) were resistant to erythromycin and clindamycin and 3 isolates were fluoroquinolone-resistant, containing associated mutations in gyrA and parC genes. All isolates were positive for one of four homologous Alpha/Rib family determinants and 1-2 of the three main pilus types.
Predominant serotypes were II, Ia, and V. A limited number of clonal types were identified with two STs accounting for about half of the isolates. All strains collected in this study were susceptible to beta-lactam antibiotics and vancomycin. Typical of most GBS, these isolates were positive for single alpha-like family protein, serine-rich repeat gene, as well as 1-2 pilus determinants.
无乳链球菌（B 群链球菌，GBS）血清型、序列型和抗生素耐药谱在不同地理位置有所不同，这影响了新生儿的疾病模式。这些差异是疫苗开发工作的重要考虑因素，而非洲大国的数据有限。本研究的目的是确定来自埃塞俄比亚孕妇及其新生儿的 GBS 分离株的血清型和基因型。
2014 年 6 月至 2015 年 9 月，在埃塞俄比亚的三家医院进行了一项基于医院的横断面研究。从 225 株 GBS 分离株中，回收、确认并在疾病预防控制中心的链球菌实验室使用常规微生物学方法和全基因组测序对 121 株 GBS 进行了特征分析。
121 株分离株中，87 株来自孕妇直肠阴道样本，32 株来自新生儿不同部位，2 株来自疑似败血症新生儿血液。有 25 对母婴，24 对具有一致的菌株。母亲及其婴儿中最常见的血清型为 II、Ia 和 V（分别为 41.5%、20.6%、19.5%和 40.6%，25%和 15.6%）。对 83 株分离株的多位点序列分型（MLST）显示，ST10（24 株；28.9%）和 ST2（12 株；14.5%）是最主要的序列类型。所有 GBS 菌株均对青霉素、头孢噻肟和万古霉素敏感，这与野生型 PBP2x 类型的存在和缺乏已知的万古霉素耐药基因有关。四环素耐药率较高（73 株；88%，主要与 tetM 相关，但也与 tetO 和 tetL 相关）。5 株（6%）对红霉素和克林霉素耐药，3 株对氟喹诺酮耐药，gyrA 和 parC 基因存在相关突变。所有分离株均携带 4 种同源 Alpha/Rib 家族决定簇中的 1 种和 3 种主要菌毛类型中的 1-2 种。
主要血清型为 II、Ia 和 V。确定了少数几个克隆型，其中两个 ST 占了大约一半的分离株。本研究中采集的所有菌株均对β-内酰胺类抗生素和万古霉素敏感。与大多数 GBS 一样，这些分离株均为阳性，带有单一种类的 Alpha 样家族蛋白、丝氨酸丰富重复基因以及 1-2 种菌毛决定簇。
