Antimicrobial Resistance in Enteric Pathogens and Its Implications for Empiric Therapy in Community-Acquired Diarrhea: A Systematic Review and Meta-Analysis

Background: Community-acquired diarrhea remains a major global health problem, and bacterial enteric pathogens account for a substantial proportion of clinically significant cases. Antimicrobial therapy is indicated in selected scenarios; however, escalating antimicrobial resistance (AMR) threatens the effectiveness of empiric treatment strategies, particularly in low- and middle-income countries. Objective: To systematically evaluate and quantify antimicrobial resistance patterns among major bacterial enteric pathogens causing community-acquired diarrhea. Methods: A systematic review and meta-analysis was conducted in accordance with PRISMA 2020 guidelines. PubMed/MEDLINE, Embase, Scopus, Web of Science, and the Cochrane Library were searched from inception to June 2025. Community-based and outpatient studies reporting phenotypic antimicrobial susceptibility of Escherichia coli, Shigella spp., Salmonella spp., Campylobacter spp., and Vibrio cholerae were included. Random-effects meta-analyses were used to estimate pooled resistance proportions, and heterogeneity was assessed using the I² statistic. Results: A total of 47 studies were included, with 39 contributing to meta-analysis, encompassing 18,742 bacterial isolates. High pooled resistance was observed to ampicillin and trimethoprim–sulfamethoxazole across E. coli (56% and 71%), Shigella (76% and 64%), and Salmonella (55% and 25%). Ciprofloxacin resistance remained relatively low overall but showed marked regional variability. Campylobacter spp. demonstrated clinically concerning resistance to erythromycin (33%) and ciprofloxacin (27%). Substantial heterogeneity was noted across most pathogen–antibiotic combinations. Conclusion: Antimicrobial resistance among enteric pathogens causing community-acquired diarrhea is widespread and undermines the reliability of several commonly used oral agents. The findings highlight the need for region-specific empiric treatment guidelines, strengthened community-based AMR surveillance, and robust antimicrobial stewardship to preserve remaining therapeutic options