Prevalence of group B streptococcal colonization in the healthy non-pregnant population: a systematic review and meta-analysis
Merel N. van Kassel, Sanne W.C.M. Janssen, Sanne Kofman, Matthijs C. Brouwer, Diederik van de Beek, Merijn W. Bijlsma
Abstract
BACKGROUND: Colonization and transmission precede invasive group B streptococcal (GBS) disease. Data on GBS colonization prevalence, detection methods and risk factors for carriage are relevant for vaccine development and to understand GBS pathogenesis. OBJECTIVES: To evaluate GBS colonization prevalence after the first week of life in the healthy non-pregnant population. DATA SOURCES: Pubmed/Medline, Embase, Latin American and Caribbean Health Sciences Literature, World Health Organization Library Information System, and Scopus. Search performed 12 January 2021 with search terms related to 'GBS' and 'colonization, epidemiology, prevalence or screening' without restrictions. STUDY ELIGIBILITY CRITERIA: All studies that reported prevalence of GBS colonization (any site) in the healthy population. PARTICIPANTS: All individuals (>6 days of age), with no indication of pregnancy, invasive disease or severe underlying immunological co-morbidities. METHODS: Logit transformation and a random effects model (DerSimonian and Laird) were used to pool colonization estimates. Subgroup analysis and meta-regression on a priori determined subgroups were performed. RESULTS: = 6%). Higher prevalence was found with selective culture methods (19%, 95% CI 16%-23% versus non-selective methods 8%, 95% CI 6%-9%; p < 0.0001). Colonization rates were highest in rectum (19%, 95% CI 15%-24%), vagina (14%, 95% CI 12%-17%) and urethra (9%, 95% CI 5%-18%). In participants with negative rectal cultures, 7% (95% CI 5%-9%) had GBS cultured from another niche. Colonization prevalence was lower in children (6 months to 16 years; 3%, 95% CI 2%-5%) compared with adults (16%, 95% CI 14%-20%; p < 0.0001). Using selective culture methods in adults resulted in a prevalence of 26% (95% CI 19%-33%) rectal, 21% (95% CI 17%-25%) vaginal and 9% (95% CI 6%-14%) urethral colonization. CONCLUSION: The rectum is the most common body site colonized by GBS. The best approach to screen for any GBS colonization is to screen multiple body sites using selective culture methods.