One Health Determinants of Rectal Colonization by ESBL-Producing Enterobacterales in the Community

Antimicrobial resistance (AMR) is recognized as one of the greatest global public health threats. Although healthcare-associated drivers of AMR have been extensively studied, increasing evidence suggests that environmental, occupational, agricultural, socioeconomic, and ecological factors contribute substantially to the emergence and dissemination of resistant microorganisms in the community. The One Health approach recognizes the interconnectedness of human, animal, and environmental health and provides a comprehensive framework for understanding these complex interactions.

Extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales represent one of the most relevant indicators of community-associated antimicrobial resistance. Intestinal colonization by ESBL-producing Enterobacterales serves as a reservoir for subsequent infections and transmission and has been proposed by the World Health Organization as a key surveillance indicator for monitoring antimicrobial resistance across human, animal, and environmental sectors.

This multicenter observational study aims to estimate the prevalence of intestinal colonization by ESBL-producing Enterobacterales among community-dwelling adults from different territorial regions of Argentina and to investigate biological, clinical, sociocultural, occupational, and environmental determinants associated with colonization.

The study is based on the hypothesis that colonization by ESBL-producing Enterobacterales is influenced not only by traditional healthcare-related factors and antibiotic exposure, but also by environmental and occupational determinants, including contact with food-producing animals, agricultural activities, water access, socioeconomic conditions, dietary patterns, and exposure to pesticides. Particular attention will be given to glyphosate exposure because of emerging evidence suggesting potential effects on microbial ecology and selection of resistant bacterial populations.

Participants will undergo collection of epidemiological information through standardized questionnaires addressing sociodemographic characteristics, medical history, medication use, occupational exposures, environmental conditions, dietary habits, animal contact, and other variables potentially related to antimicrobial resistance. Qualitative interviews will also be performed in selected participants to explore contextual and behavioral dimensions that may contribute to antimicrobial resistance emergence and dissemination.

Biological specimens will include fecal samples and urine samples. Microbiological analyses will be performed to identify intestinal colonization by ESBL-producing Enterobacterales. Isolates will undergo microbiological characterization and preservation for future molecular analyses. Fecal and urine specimens will be incorporated into an institutional biobank under established ethical and regulatory standards.

A subset of participants will undergo urinary glyphosate measurements based on environmental vulnerability indicators derived from questionnaire data. Glyphosate quantification will be performed using validated liquid chromatography-tandem mass spectrometry methods. Additional environmental biomarkers may be evaluated in the future depending on funding availability.

Future stages of the project will include integrated multi-omics analyses of fecal samples, including microbiome, resistome, metagenomic, metatranscriptomic, and metabolomic characterization. These analyses aim to investigate the relationship between microbial community composition, antimicrobial resistance determinants, environmental exposures, and intestinal colonization by resistant Enterobacterales.

The study will initially be conducted in two sentinel healthcare institutions representing different territorial contexts in Argentina: Hospital Italiano de Buenos Aires and Hospital J. B. Iturraspe in Santa Fe Province. The long-term objective is to expand the network to additional geographical regions and develop analytical ecological models capable of evaluating interactions between community-level determinants, microbiome composition, environmental exposures, and antimicrobial resistance.

By integrating microbiological, epidemiological, environmental, molecular, and qualitative information under a One Health framework, this study seeks to generate evidence regarding the mechanisms underlying community-associated antimicrobial resistance and to support the development of preventive strategies, surveillance initiatives, and public health interventions aimed at reducing the burden of antimicrobial resistance in Argentina.

Inclusion criteria

• Adults aged 18 years or older.
• Resident for at least 1 year in one of the territorial areas included in the study.
• Community-dwelling individuals attending participating healthcare facilities (outpatient clinics, emergency departments, or hospitalized for less than 24 hours) or their accompanying family members/caregivers.
• Able and willing to provide informed consent.
• Able to provide fecal and urine samples.

Exclusion criteria

• Hospitalization within the previous 6 months.
• Antibiotic treatment within the previous 6 months.
• Current or recent oncologic treatment, immunotherapy, or immunosuppressive therapy within the previous 6 months.
• Use of laxatives within the previous 15 days.
• Pregnancy or breastfeeding.
• Inability to provide informed consent.
• Residence outside the study territorial areas.