| Congresso Brasileiro de Microbiologia 2023 | Resumo: 557-1 | ||||
Resumo:Hospital-acquired infections caused by Enterococcus faecalis strains have been emerging worldwide. On the other hand, E. faecalis can be found in non-hospital sources, including the environment. Due to the emergence of multidrug-resistant (MDR) enterococci, linezolid has become an important antimicrobial agent used in the treatment of infections caused by them. Worryingly, linezolid resistance genes (e.g., cfr, optrA, and poxtA) mediated by plasmids have been spreading rapidly. Therefore, this study aimed to isolate and characterize linezolid-resistant E. faecalis strains from Brazilian aquatic environments. One hundred and thirty-eight water samples were collected between 2020 and 2021 from different cities located in the state of São Paulo, Brazil. The water samples were filtered using sterile membranes with pore sizes of 0.45 μm, which were subsequently transferred to Petri dishes containing kanamycin esculin azide agar supplemented with 4 mg/L of linezolid. Molecular identification was carried out using species-specific targets by conventional polymerase chain reactions (PCRs). The antimicrobial susceptibility testing was performed using the disk diffusion method. The minimum inhibitory concentration (MIC) for linezolid and vancomycin was determined using the broth microdilution method. The high-level resistance to aminoglycosides (HLAR) and ciprofloxacin (HLCR) were performed using the agar-screening method. Antimicrobial resistance genes (ARGs) were screened by PCRs. Forty-eight E. faecalis strains were obtained from rivers and streams of 51 cities. All strains were resistant to at least four antimicrobial classes, being classified as MDR. Furthermore, E. faecalis strains presented MICs from 0.5 to > 64 mg/L to linezolid, and 1 from 8 mg/L to vancomycin. The HLAR and HLCR were detected in 27 and six strains, respectively. The optrA gene was identified in all strains, while the poxtA was found in five strains. In addition, these strains also carried other ARGs, including erm(A), erm(B), erm(C), tet(O), fexA, and fexB. These findings highlight the coexistence of optrA and poxtA genes in E. faecalis strains and the occurrence of MDR and ARGs-producing strains in different aquatic environments. Therefore, our results draw attention to the spread of resistance to linezolid in the environment and reinforce the importance of this sector in the transmission of antimicrobial resistance Palavras-chave: Enterococcus faecalis, linezolid resistance, optrA, poxtA, water Agência de fomento:This study was supported by FAPESP (2021/01655-7), CAPES (88887.519091/2020-00, 8887.824722/2023-00, and Finance Code 001), and CNPq (304905/2022-4, 308914/2019-8, 130086/2021-5, 141016/2021-3, and 150712/2022-7) | |||||