Colonization of Group B Streptococcus in Pregnant Women and Their Neonates from a Sri Lankan Hospital

Abstract

We investigated the molecular epidemiology of Streptococcus agalactiae (Group B Streptococcus, GBS) from carriage in a cohort of pregnant mothers and their respective newborns in a Teaching Hospital in Sri Lanka. GBS vaginal carriage was assessed on pregnant mothers at pre-delivery (n = 250), post-delivery (n = 130), and from peri-rectal swabs of neonates (n = 159) in a prospective study. All colonizing, non-duplicate GBS isolates (n = 60) were analyzed for antimicrobial susceptibilities, capsular serotyping, and whole-genome sequencing (WGS). The percentage of GBS carriage in mothers in the pre-delivery and post-delivery cohorts were 11.2% (n = 28) and 19.2% (n = 25), respectively, and 4.4% (n = 7) in neonates. GBS isolates predominantly belonged to serotype VI (17/60, 28.3%). The isolates spanned across 12 sequence types (STs), with ST1 (24/60, 40%) being the most predominant ST. Concomitant resistance to erythromycin, tetracyclines, and gentamicin was observed in eight strains (13.3%). WGS revealed the presence of antimicrobial resistance genes including ermA (5/60), mefA (1/60), msrD (1/60), and tetLMO (2/60, 28/60, and 1/60, respectively) among 60 strains. The study provides insight into the diversity of vaccine targets of GBS since serotype VI is yet to be covered in the vaccine development program.

Antibiotic Sensitivity of Group B Streptococcus from Pregnant Mothers and Its Association with Resistance Genes

“…The findings of the current study differ from a previous study done in Sri Lanka where Dissanayake et al [20] in 2015 reported penicillin sensitivity of 66.7%. Interestingly, a more recent study carried out in Sri Lanka by Sapugahawatte et al [21] in 2022 concluded similar findings to the current study, in that penicillin sensitivity was determined to be 100%.…”

“…The mefA gene was found only in 4.4% of erythromycin-resistant GBS isolates in the current study; however, an association between the gene and the erythromycin resistance could not be determined. Sapugahawatte et al [21] in 2022 in Sri Lanka found that 6.6% of erythromycin-resistant strains possessed either ermA or mefA genes. Similar results were found in Zimbabwe (3.4%) [26] and South Africa (6%) [14] , while Poyart et al [28] also reported similar findings in France.…”

Molecular characterization and antimicrobial resistance of Streptococcus agalactiae isolated from pregnant women in Japan, 2017–2021

“…The similar diversity in CC1 has also been observed in Italy ( Piccinelli et al. 2015 ), Sri Lanka ( Sapugahawatte et al. 2022 ), and other regions of Japan ( Morozumi et al.…”

Molecular characteristics and antibiotic resistance mechanisms of clindamycin-resistant Streptococcus agalactiae isolates in China

“…According to the China Bacterial Drug Resistance Monitoring Network (CHINET), the resistance rates of S. agalactiae to clindamycin and erythromycin were as high as 59.7 and 74.5%, respectively, among 5,052 clinical strains between January and June 2022. The prevalence of S. agalactiae with MLSb phenotypes is increasing, and resistance mechanisms to clindamycin and erythromycin are multitudinous, including methyltransferases encoded by erm family genes, as well as mef and mre family genes encoding antibiotic efflux pumps (Gizachew et al, 2019;Meehan et al, 2021;Sapugahawatte et al, 2022). Fluoroquinolones are one of the important antibiotic classes for the treatment of S. agalactiae infection in adults, and mutations in gyrA and parC, encoding for DNA gyrase subunit and topoisomerase IV, respectively, reduce fluoroquinolone binding to their DNA targets, leading to enhanced tolerance to quinolones (Arias et al, 2019).…”

“…The main serotypes associated with human pathogenesis are IA, IB, II, III, and V (Russell et al, 2017;Francois et al, 2019;Zhu et al, 2020), and the frequency of detecting serotypes varies based on geographical dispersion and other unknown factors. For example, serotypes III, V, and VI were dominant in Sri Lanka (Sapugahawatte et al, 2022), the frequency of serotype IA was higher than that of other serotypes in Brazil (Do et al, 2019), and serotype III was dominant in China (Cheng et al, 2020). Virulence factors include the α protein family (Alpha, Rib, Alp1 and Alp2/3; Furfaro et al, 2018;Paoletti and Kasper, 2019), serine-rich repeat protein (Srr; Seo et al, 2013;Lannes-Costa et al, 2021), hypervirulent GBS adhesin (HvgA; Tazi et al, 2010), laminin-binding protein (Lmb; Sridharan et al, 2019), Christie-Atkins-Munch-Petersen (CAMP) factor (Lang andPalmer, 2003), andpili (de Figueiredo et al, 2021a), all of which play important roles in infection type and severity.…”