Antimicrobial Usage Factors and Resistance Profiles of Shiga Toxin-Producing Escherichia coli in Backyard Production Systems From Central Chile

Erika Pavez-Muñoz; Camilo González; Bastián Fernández-Sanhueza; Fernando Sánchez; Beatriz Escobar; Romina Ramos; Verónica Fuenzalida; Nicolás Galarce; Gabriel Arriagada; Víctor Neira; Jeannette Muñoz-Aguayo; Cristian Flores-Figueroa; Timothy J Johnson; Raúl Alegría-Morán

doi:10.3389/fvets.2020.595149

Antimicrobial Usage Factors and Resistance Profiles of Shiga Toxin-Producing Escherichia coli in Backyard Production Systems From Central Chile

Front Vet Sci. 2021 Jan 15:7:595149. doi: 10.3389/fvets.2020.595149. eCollection 2020.

Authors

Affiliations

¹ Departamento de Medicina Preventiva Animal, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago, Chile.
² Instituto de Ciencias Agroalimentarias, Animales y Ambientales-ICA3, Universidad de O'Higgins, Rancagua, Chile.
³ Mid-Central Research and Outreach Center, University of Minnesota, Saint Paul, MN, United States.
⁴ Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, MN, United States.
⁵ Facultad de Ciencias Agropecuarias y Ambientales, Universidad Pedro de Valdivia, Santiago, Chile.

Abstract

Shiga toxin-producing Escherichia coli (STEC) is a zoonotic pathogen and important cause of foodborne disease worldwide. Many animal species in backyard production systems (BPS) harbor STEC, systems characterized by low biosecurity and technification. No information is reported on STEC circulation, antimicrobial resistance (AMR) and potential drivers of antimicrobial usage in Chilean BPS, increasing the risk of maintenance and transmission of zoonotic pathogens and AMR generation. Thus, the aim of this study was to characterize phenotypic and genotypic AMR and to study the epidemiology of STEC isolated in BPS from Metropolitana region, Chile. A total of 85 BPS were sampled. Minimal inhibitory concentration and whole genome sequencing was assessed in 10 STEC strain isolated from BPS. All strains were cephalexin-resistant (100%, n = 10), and five strains were resistant to chloramphenicol (50%). The most frequent serotype was O113:H21 (40%), followed by O76:H19 (40%), O91:H14 (10%), and O130:H11 (10%). The stx1 type was detected in all isolated strains, while stx2 was only detected in two strains. The Stx subtype most frequently detected was stx1c (80%), followed by stx1a (20%), stx2b (10%), and stx2d (10%). All strains harbored chromosomal bla _AmpC. Principal component analysis shows that BPS size, number of cattle, pet and horse, and elevation act as driver of antimicrobial usage. Logistic multivariable regression shows that recognition of diseases in animals (p = 0.038; OR = 9.382; 95% CI: 1.138-77.345), neighboring poultry and/or swine BPS (p = 0.006; OR = 10.564; 95% CI: 1.996-55.894), visit of Veterinary Officials (p = 0.010; OR = 76.178; 95% CI: 2.860-2029.315) and close contact between animal species in the BPS (p = 0.021; OR = 9.030; 95% CI: 1.385-58.888) increase significantly the risk of antimicrobial use in BPS. This is the first evidence of STEC strains circulating in BPS in Chile, exhibiting phenotypic AMR, representing a threat for animal and public health. Additionally, we identified factors acting as drivers for antimicrobial usage in BPS, highlighting the importance of integration of these populations into surveillance and education programs to tackle the potential development of antimicrobial resistance and therefore the risk for ecosystemic health.

Keywords: Shiga toxin-producing Escherichia coli; antimicrobial resistance; antimicrobial use; backyard production systems; one health; zoonoses.