Global Overview of Group B Streptococcus (GBS) in Dairy Cattle: Prevalence, Distribution, and Association with Mastitis - A Systematic Review and Meta-analysis

Abstract

Context: Group B Streptococcus (GBS) remains one of the most important contagious pathogens associated with bovine mastitis, causing substantial economic losses in dairy production and raising concerns regarding antimicrobial resistance. Evidence Acquisition: A PRISMA-based systematic review (2000 - 2022) analyzed studies on GBS in cattle using multiple databases, with independent screening, data extraction, and meta-analysis in STATA. Results: From 1,691 records, 115 studies were included. GBS prevalence in dairy cows was 5.9% by culture and 16.2% by PCR, with a mastitis prevalence of 35%. Antimicrobial resistance was notable, particularly to penicillin and tetracycline. The review primarily addresses prevalence in cattle and milk samples rather than direct transmission to humans. Discussion: Standardized diagnosis, improved control strategies, and stronger antimicrobial stewardship are urgently needed to reduce GBS-related economic and health impacts in dairy farming.