ENTERIC PATHOGEN SURVEILLANCE AT THE HOSPITAL–COMMUNITY INTERFACE: A LARGE-SCALE RETROSPECTIVE ANALYSIS OF CARY-BLAIR TRANSPORT SAMPLES

Abstract

Background: Enteric infections remain a major contributor to global morbidity, driven by complex interactions between environmental contamination and healthcare-associated transmission. However, the epidemiological link between hospital and community reservoirs remains insufficiently characterized. Objectives: This study aimed to investigate the distribution, prevalence, and antimicrobial resistance patterns of enteric pathogens at the hospital–community interface using Cary-Blair transport samples, with a focus on identifying transmission dynamics and environmental reservoirs. Methods: A cross-sectional study was conducted on 71,453 clinical and environmental samples collected from hospital and community settings. Samples were transported using Cary-Blair medium and processed using standard culture techniques, biochemical identification, and antimicrobial susceptibility testing following CLSI guidelines. Statistical analysis was performed to compare pathogen distribution and resistance patterns across settings. Results: The overall culture positivity rate was 25%, yielding 17,863 isolates. Escherichia coli was the predominant organism (48%), followed by Salmonella spp. (22%) and Shigella spp. (16%). E. coli was significantly more prevalent in hospital samples, whereas Salmonella predominated in community settings (p < 0.05). Environmental contamination was substantial in both settings, particularly in sanitation-related sites. High antimicrobial resistance was observed, notably to ampicillin (72%) and ciprofloxacin (58%). Multidrug resistance was significantly higher in hospital isolates (38%) compared to community isolates (21%) (p < 0.01). Conclusion: The findings demonstrate a dynamic and bidirectional transmission of enteric pathogens between hospital and community environments, compounded by rising antimicrobial resistance. Strengthening integrated surveillance systems, environmental sanitation, and antimicrobial stewardship is critical to controlling the spread of enteric infections and mitigating resistance at a population level.