THE NEW lnu(G)-CARRYING TRANSPOSON Tn6371 IN ST710 AND ST330 Enterococcus faecalis FROM FOOD-PRODUCING ANIMALS IN BRAZIL

LIMA, L. F. S.; SANTOS, C. S.; SILVA, N. C.; SILVA, A. T.; CAVALCANTE JÚNIOR, J. C. G.; CALUMBY, R. J. N.; FILSNER, P.; MORENO, A. M.; GRILLO, L. A. M.; ALMEIDA, L. M.

Congreso; 30º Congresso Brasileiro de Microbiologia; 2019

The lincosamides lincomycin, clindamycin and pirlimycin are highly important veterinary antimicrobial agents. Resistance to lincosamides in bacteria from food-producing animals, including zoonotic pathogens, has emerged due to multidrug resistance genes coding for 23S rRNA methylases, ATP-binding cassette transporters, and lincosamide nucleotidyltransferase lnu genes coding enzymes that inactivate the antibiotic by adenylylation. Here we report a new lnu(G)-carrying transposon (Tn6371) in five Enterococcus faecalis multidrug resistant strains (ST710 and ST330) isolated from healthy nursery pigs from two unrelated piggeries located in the states of São Paulo and Paraná, Brazil. Genomic DNA was sequenced (Illumina Miseq), assembled (CLC 8.0.3) and annotated (NCBI?s PGAP). Minimum inhibitory concentration (MIC) was determined by broth microdilution testing (CLSI). All E. faecalis strains exhibited elevated MICs for lincosamides. The 4738-bp Tn6371 DNA segment was found to be inserted at the chromosomal radC gene. Tn6371 is a Tn554 family transposon carrying an 804 bp-lnu(G) gene (lincosamide inactivation nucleotidylation). The upstream region of Tn6371 was composed of a 453-bp beta-phosphoglucomutase gene, while downstream a 201-bp cold shock protein cspA gene was detected. Tn6371 was inserted into the chromosome, but we confirmed by PCR and Sanger that it could be circularized in these 5 E. faecalis strains. Tn6371 carried variants of the transposase genes tnpA, tnpB and tnpC from Tn554, showing, respectively, 97.8%, 91.7%, and 82% DNA identity, and the lnu(G) gene sequence showed 100% DNA identity with various lnu(G) sequences from Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium, Salmonella enterica, and uncultured bacteria. The characterization of new mobile genetic elements is important forunderstanding the dissemination of resistance and evolution of multidrug resistant bacterial pathogens. A new mobile element (Tn6371) carrying the lincosamide nucleotidyltransferase gene lnu(G), which was recently found in China, was identified and described in E. faecalis from swine in Brazil.