Coexistence of the Oxazolidinone Resistance–Associated Genes cfr and optrA in Enterococcus faecalis From a Healthy Piglet in Brazil

Abstract

Oxazolidinones are one of the most important antimicrobials potentially active against glycopeptide-and β-lactam-resistant Gram-positive pathogens. Linezolid-the first oxazolidinone to be approved for clinical use in 2000 by the US Food and Drug Administration-and the newer molecule in the class, tedizolid, inhibit protein synthesis by suppressing the formation of the 70S ribosomal complex in bacteria. Over the past two decades, transferable oxazolidinone resistance genes, in particular cfr and optrA, have been identified in Firmicutes isolated from healthcare-related infections, livestock, and the environment. Our goals in this study were to investigate the genetic contexts and the transferability of the cfr and optrA genes and examine genomic features, such as antimicrobial resistance genes, plasmid incompatibility types, and CRISPR-Cas defenses of a linezolid-resistant Enterococcus faecalis isolated in feces from a healthy pig during an antimicrobial surveillance program for animal production in Brazil. The cfr gene was found to be integrated into a transposon-like structure of 7,759 nt flanked by IS1216E and capable of excising and circularizing, distinguishing it from known genetic contexts for cfr in Enterococcus spp., while optrA was inserted into an Inc18 broad host-range plasmid of >58 kb. Conjugal transfer of cfr and optrA was shown by filter mating. The coexistence of cfr and optrA in an E. faecalis isolated from a healthy nursery pig highlights the need for monitoring the use of antibiotics in the Brazilian swine production system for controlling spread and proliferation of antibiotic resistance.

Evidence of Linezolid Resistance and Virulence Factors in Enterococcus spp. Isolates from Wild and Domestic Ruminants, Italy

“…Furthermore, molecular investigations have allowed the detection of the LNZ resistance gene, cfr (D), in all phenotypical resistant E. faecium and E. gallinarum . This gene has recently been described as a new variant of the cfr gene in E. faecium from human clinical isolates in France, Ireland, the Netherlands, and Australia [ 25 , 26 , 27 , 28 ], and in E. faecalis from Spanish hospital isolates [ 11 ].…”

Conjugation Operons in Gram-Positive Bacteria with and without Antitermination Systems

“…This view may be supported by the observation that plasmids of the pLS20 family are all harbored by different Bacillus species, suggesting that they have a narrow host range [ 31 ]. Consistent with this view, the Inc18 plasmids are known to have a very broad host range [ 43 , 62 , 63 , 64 ]. It has been shown that the plasmids pIP501 and pAMβ1 can be introduced by conjugation into a wide variety of Gram-positive bacteria, and that the conjugation systems of these plasmids are functional in non-native hosts [ 43 , 65 , 66 , 67 , 68 , 69 ].…”

Florfenicol and oxazolidone resistance status in livestock farms revealed by short- and long-read metagenomic sequencing

“…FloR and cfr were carried in the Tn 7 -like structure, which indicated that Tn 7 -like elements might play a role in mediating floR and cfr transmission. Tn 558 has been an important dissemination media of optrA and has been reported all over the world ( Tsilipounidaki et al, 2019 ; Almeida et al, 2020a , b ). Tn 558 normally surrounds optrA and mediates their transfer ( He et al, 2016 ).…”