Dados do Trabalho

Título

Phenotypic and Molecular Evaluation of ESBL-Producing Enterobacteria Isolated from Dairy Products in the Brazilian Semiarid Region

Introdução

The dairy production chain in Brazil plays a significant financial role, and to prevent product loss or animal illness, collective and early treatment with antibiotics is employed. This practice is associated with the emergence of antibiotic-resistant microorganisms, such as Enterobacteriaceae producing extended-spectrum β-lactamases (ESBLs). These enzymes hydrolyze most β-lactams, except cephamycins and carbapenems, with the CTX-M, SHV and TEM families being the most widespread enzymes. The presence of ESBL-producing Enterobacteriaceae in dairy products raises human health concerns due to the potential transmission.

Objetivo (s)

To detect ESBL-producing Enterobacteriaceae in dairy products in the Brazilian semiarid region.

Material e Métodos

Between June 2022 and February 2024, 70 samples of dairy products were collected from companies in the region near Mossoró-RN. After transportation to the laboratory, the samples were incubated at 37°C for 24h in peptone water (1/10). After incubation, 100µl were inoculated onto MacConkey Agar (2µg/ml of Ceftriaxone) and incubated at 37°C for 24h. When growth occurred, at least two colonies of distinct morphotypes were re-isolated and identified using conventional biochemical tests. The isolates identified as Enterobacteriaceae were subjected to antimicrobial susceptibility testing by disk diffusion; the Drop-test (polymyxin resistance); the double-disk synergy test (DDST) for ESBL detection; and PCR for the blaCTX-M, blaSHV, and blaTEM genes.

Resultados e Conclusão

Enterobacteriaceae growth was observed in 26 samples (37%), allowing the identification of 30 distinct isolates (19 Escherichia coli, 10 Klebsiella spp., and 1 Hafnia sp.). A total of 26 isolates (87%) were ESBL positive, and most were susceptible to almost all tested antimicrobials, except ceftriaxone (93.3%), ceftazidime (90%), and cefepime (83%). Only one isolate (3%) was resistant to polymyxin B. It was observed that 22 (73.3%) possessed the blaCTX-M gene, 10 (33%) the blaSHV gene, and 6 (20%) the blaTEM gene. The concurrent presence of all three genes was detected in three isolates (10%), while eight (27%) did not present any of them. This study highlights a significant presence of ESBL-producing Enterobacteriaceae in dairy products in the Brazilian semiarid region, with a high dissemination rate of the blaCTX-M gene. Therefore, it is crucial to further investigate the spread of these resistance determinants in the dairy production chain.

Palavras Chave

Enterobacteriaceae; Beta-Lactamases; Dairy Products.