One Health surveillance of environmental Escherichia coli and antimicrobial
resistance in broiler production systems in Morocco

Background: Broiler production environments can act as reservoirs for Escherichia coli and
antimicrobial resistance (AMR), facilitating dissemination through manure, soil, and water
interfaces. However, matrix-resolved environmental data remain limited in North Africa.
Objectives: To estimate the prevalence of E. coli across key broiler-farm environmental matrices
and to characterize phenotypic AMR, including ESBL production and multidrug resistance
(MDR), among recovered isolates.
Methods: A cross-sectional survey was conducted in 13 broiler farms in the
Rabat–Salé–Zemmour–Zaer area (Morocco) from 24 November 2023 to 5 May 2025. A total of
506 samples were collected from poultry manure, drinking troughs, soil (on-farm), soil at 200 m
and 500 m from farms, and well water. Solid samples (25 g) were pre-enriched in buffered
peptone water (25 g + 225 mL) and plated on EMB agar; well water was analyzed by membrane
filtration (100 mL; 0.45 µm). Identification was confirmed using API 20E. Antimicrobial
susceptibility testing was performed by Kirby–Bauer disc diffusion against 20 antibiotics (CLSI
2020). ESBL phenotype was assessed by double-disc synergy/combination testing and confirmed
on Brilliance™ ESBL agar. Prevalence and susceptibility proportions were reported with 95%
exact binomial confidence intervals (R). MDR was defined as resistance to ≥1 agent in ≥3
antimicrobial classes.
Results: Overall, E. coli was detected in 190/506 samples (37.5%, 95% CI: 33.3–41.9).
Prevalence was highest in poultry manure (48.1%) and soils (38.0–44.3%), and lowest in well
water (23.2%). Among 190 isolates, resistance was highest to ampicillin (84.7%), tetracycline
(61.6%), amoxicillin (56.8%), and chloramphenicol (55.8%), with notable resistance to
nalidixic acid (44.7%), trimethoprim–sulfamethoxazole (36.3%), and ciprofloxacin (32.6%).
Resistance to carbapenems was rare (0–0.5%), and susceptibility to cefepime and
piperacillin–tazobactam was near-complete. ESBL phenotype was detected in 35/190 isolates
(18.4%), and MDR was observed in 110/190 isolates (57.9%).
Conclusion: E. coli and clinically relevant AMR phenotypes (ESBL and MDR) were widely
distributed across broiler-farm environmental matrices, particularly manure and soils, supporting
the need for strengthened antimicrobial stewardship and targeted environmental risk management
within a One Health framework.