BMC Genomics | 2021
Whole genome sequence based capsular typing and antimicrobial resistance prediction of Group B streptococcal isolates from colonized pregnant women in Nigeria
Abstract
Background Streptococcus agalactiae (Group B Streptococcus, GBS) is one of the major bacterial pathogens responsible for neonatal sepsis. Whole genome sequencing has, in recent years, emerged as a reliable tool for capsular typing and antimicrobial resistance prediction. This study characterized vaginal and rectal isolates of Group B Streptococcus obtained from pregnant women in Port Harcourt, Nigeria using a whole-genome sequence-based approach. Results Capsular types Ia, Ib, II, III, IV and V were detected among the 43 isolates sequenced. Twelve sequence types (STs) were identified, with ST19 ( n \u2009=\u20099, 27.3\u2009%) and ST486 ( n \u2009=\u20095, 15.2\u2009%) the most frequent among non-duplicated isolates. Of the alpha-like proteins (alp) identified, Alp1 was the most prevalent in 11 (33.3\u2009%) isolates. Macrolide and lincosamide resistance determinants were present in 15 (45.5\u2009%) isolates; ermB was detected in 1 (3\u2009%), ermTR in 7 (21.2\u2009%) isolates, lnu gene was detected in 6 (18.2\u2009%) and mef was identified in 3 (9.1\u2009%) isolates. Resistance of GBS to erythromycin and clindamycin (predicted from presence of erm or mef genes) was found to be 30.3\u2009% and 24.2\u2009%, respectively. All isolates were predicted resistant to tetracycline with only the tetM gene identified. Fluoroquinolone-resistance conferring substitutions in gyrA \u2009+\u2009 par C were detected in 9 (27.3\u2009%) isolates and chloramphenicol resistance was predicted from presence of aac6’-aph2 gene in 11 (33.3\u2009%). Conclusions The data available from the whole genome sequencing of these isolates offers a small but insightful description of common serotypes and resistance features within colonizing GBS in Nigeria.