Maternal Colonization With Group B Streptococcus and Serotype Distribution Worldwide: Systematic Review and Meta-analyses

Abstract

BackgroundMaternal rectovaginal colonization with group B Streptococcus (GBS) is the most common pathway for GBS disease in mother, fetus, and newborn. This article, the second in a series estimating the burden of GBS, aims to determine the prevalence and serotype distribution of GBS colonizing pregnant women worldwide.MethodsWe conducted systematic literature reviews (PubMed/Medline, Embase, Latin American and Caribbean Health Sciences Literature [LILACS], World Health Organization Library Information System [WHOLIS], and Scopus), organized Chinese language searches, and sought unpublished data from investigator groups. We applied broad inclusion criteria to maximize data inputs, particularly from low- and middle-income contexts, and then applied new meta-analyses to adjust for studies with less-sensitive sampling and laboratory techniques. We undertook meta-analyses to derive pooled estimates of maternal GBS colonization prevalence at national and regional levels.ResultsThe dataset regarding colonization included 390 articles, 85 countries, and a total of 299924 pregnant women. Our adjusted estimate for maternal GBS colonization worldwide was 18% (95% confidence interval [CI], 17%–19%), with regional variation (11%–35%), and lower prevalence in Southern Asia (12.5% [95% CI, 10%–15%]) and Eastern Asia (11% [95% CI, 10%–12%]). Bacterial serotypes I–V account for 98% of identified colonizing GBS isolates worldwide. Serotype III, associated with invasive disease, accounts for 25% (95% CI, 23%–28%), but is less frequent in some South American and Asian countries. Serotypes VI–IX are more common in Asia.ConclusionsGBS colonizes pregnant women worldwide, but prevalence and serotype distribution vary, even after adjusting for laboratory methods. Lower GBS maternal colonization prevalence, with less serotype III, may help to explain lower GBS disease incidence in regions such as Asia. High prevalence worldwide, and more serotype data, are relevant to prevention efforts.

Within-Host Diversity and Vertical Transmission of Group B Streptococcus Among Mother-infant Dyads in The Gambia

“…We found a nasopharyngeal colonisation prevalence of 16.33% in mothers and 18.37% in their infants. These results are consistent with a recent meta-analysis of global maternal GBS colonisation, which reported a prevalence of 15% regardless of sampling site [19], and with the neonatal prevalence rate we previously reported in a two-month-old infant cohort [13].…”

Group B streptococci in pregnancy: New perspectives for old challenges

“…Obstetric data and bacteriological cultures were available for 2121 participants. The study found a prevalence of 4.9% for vaginal colonisation with GBS, lower than the anogenital colonisation reported in the Caribbean, Europe and North America, and comparable to rates previously found in southern and eastern Asia . Women with a BMI over 28 kg/m 2 before pregnancy had a significantly higher rate of colonisation as compared to those with a BMI under 28 kg/m 2 .…”

“…GBS is part of the normal intestinal and vaginal flora. It colonises up to 40% of adults and between 3% and 41% of the pregnant women worldwide . GBS carriage in the anorectal or vaginal flora can be intermittent, transient or persistent .…”

Universal screening versus risk‐based protocols for antibiotic prophylaxis during childbirth to prevent early‐onset group B streptococcal disease: a systematic review and meta‐analysis

“…The incidence of EOGBS is generally low, and differ per country. Still, on average the numbers correlate well with data reported elsewhere, and by comparing the changes in incidences, we could nonetheless analyse the independent impacts of the two policies.…”