Systematic Review and Meta-Analysis on Antimicrobial Resistance Patterns of Enteric Pathogens in Community-Acquired Diarrhea

Background: Community-acquired diarrhea remains a leading cause of morbidity globally, particularly in low- and middle-income countries (LMICs). Although antimicrobial therapy is reserved for selected clinical indications, rising antimicrobial resistance (AMR) among enteric bacterial pathogens increasingly compromises empiric treatment strategies. Evidence describing resistance patterns in community and outpatient settings remains fragmented.

Objectives: To systematically synthesize available evidence on antimicrobial resistance patterns among bacterial enteric pathogens causing community-acquired diarrhea and to estimate pooled resistance proportions for commonly used antimicrobials.

Methods: A systematic review and meta-analysis were conducted in accordance with PRISMA 2020 guidelines. Major bibliographic databases were searched from inception to June 2025 for studies reporting phenotypic antimicrobial resistance in community-acquired diarrheal isolates. Random-effects meta-analyses of proportions were performed for pathogen–antibiotic combinations reported in at least three studies. Heterogeneity was assessed using the I² statistic.

Results: Sixty-four studies from 23 countries, encompassing 18,742 community-acquired bacterial isolates, were included; 52 studies contributed to the meta-analysis. Pooled resistance was high for legacy first-line agents, including ampicillin and trimethoprim–sulfamethoxazole, across Escherichia coli, Shigella spp., and Salmonella spp. Resistance to ciprofloxacin and third-generation cephalosporins was lower overall but exhibited substantial geographic and pathogen-specific heterogeneity. Campylobacter spp. demonstrated concerning resistance to both macrolides and fluoroquinolones. Between-study heterogeneity was high across most analyses (I² >70%).

Conclusions: Antimicrobial resistance among enteric pathogens causing community-acquired diarrhea is widespread and undermines the effectiveness of commonly used oral agents. Emerging resistance to key therapeutic classes further limits empiric treatment options. Strengthened community-based surveillance, region-specific treatment guidance, and robust antimicrobial stewardship are urgently required to inform rational management of diarrheal disease in the era of escalating AMR