Título:	Resistência genética de isolados de Escherichia coli isoladas de queijo tipo minas frescal artesanal do Distrito Federal, Brasil
Autor(es):	Rodrigues, Letícia Fernandes Silva
Orientador(es):	Orsi, Daniela Castilho
Coorientador(es):	Silva, Izabel Cristina Rodrigues da
Assunto:	Escherichia coli Alimentos - contaminação Laticínios Vigilância em saúde
Data de publicação:	26-Jun-2026
Data de defesa:	15-Dez-2025
Referência:	RODRIGUES, Letícia Fernandes Silva. Resistência genética de isolados de Escherichia coli isoladas de queijo tipo minas frescal artesanal do Distrito Federal, Brasil. 2025. 212 f. il. Tese (Doutorado em Ciências e Tecnologias em Saúde) — Universidade de Brasília, Brasília, 2025.
Abstract:	Introduction:Antimicrobial resistance is internationally recognized as one of the major public health challenges of the 21st century. In the context of artisanal cheese production, failures in quality control processes may favor the multiplication of pathogenic microorganisms, as the intrinsic characteristics of these foods can support their persistence and growth. Escherichia coli is a ubiquitous and opportunistic microorganism that may present pathogenic serotypes and harbor antibiotic resistance genes. Despite the growing evidence of the presence of antimicrobial-resistant E. coli strains in foods of animal origin, studies integrating both phenotypic and genotypic characterization of antimicrobial resistance in fresh artisanal cheeses remain scarce, particularly at the regional level.Objective: This study aimed to characterize the phenotypic and genotypic antimicrobial resistance profiles of 104 E. coli isolates obtained from 22 samples of artisanal Minas Frescal cheeses collected in the Federal District, Brazil. Methods: Antimicrobial susceptibility of the E. coli isolates was assessed using the Kirby–Bauer disk diffusion method. Antimicrobial resistance genes were detected by polymerase chain reaction (PCR) using specific primers targeting β lactam resistance genes (blaCTX-M, blaTEM, blaSHV), tetracycline resistance genes (tetA, tetB), chloramphenicol resistance genes (cat1, clmA), and sulfonamide resistance genes (sul1, sul2). Results: The highest phenotypic resistance rates were observed for sulfonamides (85.58%; 89/104) and tetracyclines (38.46%; 40/104). Genotypically, most E. coli isolates carried sulfonamide resistance genes sul1 and sul2 (62.50%; 65/104), tetracycline resistance genes tetA and tetB (65.38%; 68/104), and β-lactam resistance genes blaCTX-M, blaTEM, and blaSHV (55.77%; 58/104). Among isolates harboring sulfonamide resistance genes, sul1 was the most frequent, present in 49.04% (51/104), and 59.61% (62/104) exhibited phenotypic resistance. Regarding tetracyclines, most isolates simultaneously carried tetA and tetB (34.61%; 36/104) and 35.56% (37/104) were phenotypically resistant, whereas 29.80% (31/104) were susceptible. Among β-lactam resistance genes, blaCTX-M was the most prevalent, detected in 21.15% (22/104) of isolates. However, most E. coli strains (43.26%; 45/104) were phenotypically susceptible to the β-lactams tested. For chloramphenicol, cat1 and clmA were identified in 22.12% (23/104) of isolates, although only 1.92% (2/104) showed phenotypic resistance. Conclusion: The findings of this study demonstrate a significant presence of antimicrobial resistance among E. coli isolates recovered from artisanal Minas Frescal cheeses in the Federal District, underscoring the importance of sanitary control and the adoption of good production and handling practices in artisanal cheesemaking. These results highlight the need for integrated actions involving surveillance, sanitary education, and rational antimicrobial use, contributing to the mitigation of risks associated with antimicrobial resistance in the food chain of animal origin.
Unidade Acadêmica:	Faculdade de Ciências e Tecnologias em Saúde (FCTS) – Campus UnB Ceilândia
Informações adicionais:	Tese (doutorado) — Universidade de Brasília, Faculdade de Ceilândia, Programa de Pós-graduação em Ciências e Tecnologias em Saúde, 2025.
Programa de pós-graduação:	Programa de Pós-Graduação em Ciências e Tecnologias em Saúde
Agência financiadora:	Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Aparece nas coleções:	Teses, dissertações e produtos pós-doutorado

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