| Congresso Brasileiro de Microbiologia 2023 | Resumo: 357-1 | ||||
Resumo:Campylobacter jejuni and C. coli are the primary species of the Campylobacter genus responsible for gastroenteritis cases worldwide. Poultry and pigs are considered reservoirs of these microorganisms, and products derived from these animals serve as important vehicles for human contamination. Although human campylobacteriosis is often self-limiting, macrolides such as erythromycin and azithromycin are the preferred choice for antimicrobial therapy when necessary. However, the emergence of antimicrobial resistance to this class of antibiotics has become a global concern. The aim of this study was to investigate erythromycin resistance in C. jejuni, and C. coli isolated from the poultry and swine chain in Brazil. A total of 118 strains were examined, including nineteen strains of C. jejuni and two strains of C. coli isolated from broiler feces, eighty strains of C. jejuni isolated from broiler carcasses, and seventeen strains of C. coli isolated from pig feces. Species identification was performed using PCR, and the minimum inhibitory concentration (MIC) for erythromycin was determined using agar dilution. Mutations A2074C and A2075G were identified using MAMA-PCR, while the presence of the ermB gene was investigated through conventional PCR. Out of the strains isolated from broiler feces, only 10.53% (2/19) C. jejuni strains showed intermediate resistance, with an MIC of 16 µg/mL. The A2075G mutation was detected in one of the intermediate resistant strains. Regarding the strains from poultry carcasses, 30.00% (24/80) exhibited resistance to erythromycin, with MIC values ≥ 64 µg/mL. Among the erythromycin-resistant strains, 62.5% (15/24) showed mutations at both positions A2074C and A2075G of the 23S rRNA gene, while 37.5% (9/24) had only the A2075G mutation. All seventeen C. coli strains isolated from swine were resistant to erythromycin, with MIC values >128 µg/mL, and possessing the A2075G mutation. None of the strains harboured the ermB gene. Target mutations at positions 2074 and 2075 of the domain V of the 23S rRNA gene are associated with macrolide resistance in Campylobacter species. These mutations represent the main mechanisms responsible for high levels of resistance to macrolides and do not provide any advantage to bacterial cells. Studies comparing colonization capacities have shown that strains without mutations outcompete mutant strains, indicating that in the absence of macrolides, these mutations decrease cell fitness, especially in C. jejuni. ErmB encodes a ribosomal metilase and is also associated with high levels of resistance in Campylobacter . While ermB-positive Campylobacter strains have been detected in several countries since their first detection in China, this gene has not been found yet in Campylobacter isolates from Brazil. In this study, we identified a high level and frequency of resistance to erythromycin in C. jejuni strains from poultry carcasses and C. coli strains from swine. The spread of these strains and their drug-resistant genes pose a risk to public health.
Palavras-chave: Antimicrobial resistance, Campylobacter, 23S rRNA Agência de fomento:Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro | |||||