What are we eating? - Detection of antibiotic resistance mechanisms in frozen chicken nuggets imported from Brazil

Sep 29, 2026

Rising antibiotic resistance threatens humans, animals, and the environment, and food can contribute to its spread. Using the One Health framework, this study assessed resistance mechanisms to critically important antibiotics in eighty frozen chicken nuggets imported from Brazil. Cultures were grown with ceftriaxone, ciprofloxacin, or colistin, then isolates were identified by MALDI-TOF and evaluated with disk diffusion. Shotgun metagenomics (SqueezeMeta) complemented conventional microbiology to characterize community composition and detected resistance genes.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages5

Reading Time13 min

AccessFree to download

Contents lists available at ScienceDirect

One Health

Article information

Abstract

Keywords

1. Introduction

2. Materials and methods

2.1 Sampling and pre-enrichment of chicken nuggets for microbiological analysis

2.2 Sampling and bacterial analysis

One Health 21 (2025) 101171 Contents lists available at ScienceDirect One Health journal [homepage:](homepage: www.elsevier.com/locate/onehlt)[ www.elsevier.com/locate/onehlt](homepage: www.elsevier.com/locate/onehlt) | What are we eating?. Detection of antibiotic resistance mechanisms in frozen chicken nuggets imported from Brazil | | | | | --- | --- | --- | --- | | Nicol´as F. Cordeiro , Nadia Coppola , Federica Ferreira , Rafael Vignoli, In´es Bado *
Departamento de Bacteriologíay Virología, Facultad de Medicina, Instituto de Higiene, Universidad de la República, Av. Alfredo Navarro 3051, CP. 11600 Montevideo, Uruguay | | | | | A R T I C L E I N F O | | A B S T R A C T | | | Keywords:
Nuggets
Frozen food Antibiotic resistance Metagenomics One health | | The rise of antibiotic resistance is a growing challenge, affecting humans, the environment, and animals. Under the One Health framework, this study investigated resistance mechanisms to critically important antibiotics in frozen chicken nuggets imported from Brazil.
Eighty nugget samples were cultured on selective media containing ceftriaxone, ciprofloxacin, or colistin. Isolates were identified using MALDI-TOF, and antibiotic susceptibility was assessed by disk diffusion. Eight samples were also analyzed using shotgun metagenomic sequencing processed through the SqueezeMeta pipeline.
Nineteen Enterobacterales resistant mainly to β-lactams and to a lesser extent, to quinolones and aminoglycosides, were identified. Eight Pseudomonas spp. were recovered, including one P. fulva resistant to colistin. Metagenomics revealed predominant Firmicutes, (Bacillaceae, Lactobacillaceae, and Paenibacillaceae) with low γ-Proteobacteria levels.
Additionally, we detected resistance genes against several antibiotics.
This study highlights the role of imported food in spreading AMR and the value of combining metagenomics with conventional microbiology to strengthen One Health surveillance. | | 1. Introduction Antibiotics are crucial for treating severe diseases. However, their overuse in human and veterinary medicine has promoted multidrugresistant microorganisms (MDR-M) driven by mechanisms such as enzyme inactivation, target modification, and diminished permeability. Antimicrobial resistance (AMR) is a global threat to humans, animals, and the environment’s health, and can spread via food, water, and trade. AMR and food are pillars of the “One Health” concept supported by the WHO and related agencies. In humans, MDR-M infections increase morbidity and mortality, hospital stays, and healthcare costs [1]. However, the highest consumption of antibiotics occurs in animal husbandry (80 %), with further increases expected by 2030 [2]. This generates therapeutic challenges in the veterinary field and facilitates the selection and transmission of MDR-M or resistance genes to humans through livestock. Foodborne pathogens like Salmonella spp. and Escherichia coli are considered major threats [3]. These microorganisms can cause economic losses in animal production, as observed in Norway, where chicken sales dropped 20 % due to resistant E. coli [4]. Food can act both as a substrate and vehicle for enteropathogens and other bacteria harboring resistance genes which may transfer them to the human microbiota [3]. In Uruguay, our group previously studied resistance genes like rmtG and mcr9 in imported chicks [5]. We aimed to investigate resistance mechanisms in frozen food from Brazil as a potential route for critical AMR gene entry. 2. Materials and methods 2.1. Sampling and pre-enrichment of chicken nuggets for microbiological analysis Eighty chicken nuggets samples imported from Brazil were studied during an 8-month period, in 2022. Chicken nuggets corresponding to five different brands (named A-E) were acquired from local supermarkets, and refrigerated and processed within 24 h. Each sample was homogenized in 100 mL of LB broth, pre-enriched at 37 ◦

FAQs

What problem does the study address in frozen chicken nuggets?

The study addresses the growing challenge of antibiotic resistance and evaluates whether frozen food imported from Brazil can harbor and spread resistance mechanisms to critically important antibiotics.

How were bacterial isolates and antibiotic susceptibility assessed?

Eighty nugget samples were cultured on selective media with ceftriaxone, ciprofloxacin, or colistin. Isolates were identified using MALDI-TOF, and susceptibility was determined using disk diffusion (Kirby-Bauer) following CLSI guidelines.

What additional approach was used besides conventional microbiology?

Shotgun metagenomic sequencing was performed on a subset of samples and processed through the SqueezeMeta pipeline, revealing predominant taxa and supporting detection of resistance genes.

Sep 29, 2026

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