| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1076-1 | ||||
Resumo:Enterococci have become important nosocomial pathogens worldwide, primarily because of their ability to acquire and transfer genes associated with antimicrobial resistance and virulence properties. Mobile genetic elements (MGEs), particularly plasmids, play a central role in the spread and maintenance of antibiotic resistance in E. faecalis and E. faecium. Despite their importance, data on the prevalence, distribution, and genetic content of specific MGEs in enterococcal populations are still relatively scarce. Therefore, we investigated the presence and content of plasmids among E. faecalis (n=63) and E. faecium (n=111) isolates obtained from hospitalized patients in Rio de Janeiro state. The isolates were characterized using MALDI-TOF MS and subjected to whole genome sequencing analysis. All sequences were de novo assembled using Unicycler prior to bacterial plasmid extraction. Assembly graphs were processed using GPlas vs 0.7.0 to predict plasmid contigs, which were subsequently validated using PlasmidFinder vs 2.1. MobileElementFinder vs 1.0.3 and BLAST tool were used to identify plasmid contents: antimicrobial resistance genes (ARGs), biocide resistance genes (BRGs), virulence genes (VGs), insertion sequences (ISs) and transposons (Tns). Population diversity was analyzed using MLST. The isolates contained plasmids carrying numerous resistance and virulence genes. In particular, plasmids from E. faecium had higher proportions of ARGs, whereas plasmids from E. faecalis were enriched in VGs. Among the twenty replicon families found in E. faecium, repUS15 (n=102) and rep17a (n=89) were the most abundant and carried ARG to: Aminoglycosides (aac(6')-aph(2''), ant(6)-Ia, aph(3')-III); macrolides [erm(B)]; vancomycin (vanHAX); chloramphenicol (cat) and tetracycline [tet(M), tet(L)]; and BRGs conferring resistance to copper (tcrB operon and cueO) and mercury (merA); and the VG for adhesion (ecbA), pili formation (pilA), and enzyme excretion (hylEfm). Plasmids rep2 and rep12 also harbored ARGs conferring macrolide-lincosamide-streptogramin resistance [erm(B), lnu(B), lnu(G), lsaA, msr(C)] and others. Similarly, thirteen different replicon types were identified in E. faecalis, with repUS43 (n=56), rep9b (n=44), rep7a (n=37), and rep9a (n=31) being the most abundant. MobileElementFinder showed that the tetracycline resistance gene tet(M) and the tpx VG were found on the repUS43 plasmid along with the Tn6009. Rep7a and rep9a/b/c contained VGs associated with cell invasion (cyl operon), aggregation (agg), pathogenic islands (hyd, cbh, esp, psaA) and ARGs (aac(6')-aph(2''), ant(6)-Ia, erm(B), vanHAX, cat), as well as trimethoprim (dfrG) and streptomycin (str) resistance. In addition, the identified plasmids were associated with other MGEs in both species, such as ISEfm2, ISEfa4, ISS1N, IS256, and IS1062 and Tn6009 and Tn917. Several major sequence types exhibited plasmids carrying ARG, VGs, BRGs, and other MGEs. Three of the major enterococcal sequence types, ST525 (n=26) and ST6 (n=19) for E. faecalis and ST78 (n=22) for E. faecium, consistently carried specific plasmids. The identification of ARGs and VGs located on plasmids and associated with Tns or ISs in both species suggest possible mobilization between different enterococcal species. The diversity of plasmids, Tns and ISs among enterococcal genomes highlights their plasticity and the potential for horizontal spread of ARGs, VGs and BRGs.
Palavras-chave: Enterococcus, Plasmids, MGEs, Antimicrobial resistance, Population diversity Agência de fomento:CNPq, INPRA, CAPES and FAPERJ. | |||||