A Conjugative MDR pMG1-Like Plasmid Carrying the lsa(E) Gene of Enterococcus faecium With Potential Transmission to Staphylococcus aureus

Abstract

lsa(E) is a pleuromutilin, lincosamide, and streptogramin A (PLSA phenotype) resistance gene that was first described in S. aureus and was thought to have been transferred from Enterococcus sp. This study aimed to elucidate the prevalence of the lsa(E) gene among E. faecium isolates at a tertiary teaching hospital and to evaluate the transferability of the lsa(E) gene from E. faecium to S. aureus in vitro. A total of 96 E. faecium strains isolated from one hospital in Beijing in 2013 were analysed for quinupristin-dalfopristin (QDA) resistance genes, and multilocus sequence typing (MLST) was performed. The transferability of QDA resistance between ten E. faecium strains and four S. aureus strains was determined by filter mating. Genome sequencing of the transconjugant was performed. A total of 46 E. faecium isolates (46/96, 47.92%) tested positive for lsa(E), while two isolates (2/96, 2.08%) tested positive for lsa(A). Thirty-six lsa(E)-positive strains (36/46, 78.3%) belonged to ST78. Among 40 mating tests, lsa(E) was successfully transferred through one conjugation at a frequency of 1.125 × 10–7 transconjugants per donor. The QDA resistance of the transconjugant N7435-R3645 was expressed at a higher level (MIC = 16 mg/L) than that of the parent S. aureus strain (MIC = 0.38 mg/L). Next-generation sequencing (NGS) analysis of the transconjugant N7435-R3645 showed that the complete sequence of the lsa(E)-carrying plasmid pN7435-R3645 had a size of 92,396 bp and a G + C content of 33% (accession no. MT022086). The genetic map of pN7435-R3645 had high nucleotide similarity and shared the main open reading frame (ORF) features with two plasmids: E. faecium pMG1 (AB206333.1) and E. faecium LS170308 (CP025078.1). The rep gene of pN7435-R3645 showed 100% identity with that of pMG1, although it did not belong to the rep1-19 family but instead a unique rep family. Multiple antibiotic resistance genes, including lsa(E), aadE and lnu(B), erm(B), ant6-Ia, and lnu(B), were present on the plasmid. In conclusion, an lsa(E)-carrying plasmid that can be transferred by conjugation from E. faecium to S. aureus in vitro was identified. This multidrug resistance (MDR) pMG1-like plasmid may act as a vector in the dissemination of antimicrobial resistance among species.

An in‐house 45‐plex array for the detection of antimicrobial resistance genes in Gram‐positive bacteria

“…Noteworthy, the Q/D resistance mechanisms are still not perfectly understood. Indeed, few studies reported that resistance to streptogramin A is sufficient to confer resistance to Q/D (Hancock, 2005;Yan et al, 2021) while others support that a combination of both resistance to streptogramin A (vat or vga family) and streptogramin B (erm family or vgbB) is required to ensure Q/D resistance (Miller et al, 2014;Zarrouk 2000). Both lsaA and lsaE are the only genes reported to confer resistance to both Q/D components (Alcock et al, 2020;Singh et al, 2002;Wendlandt et al, 2013).…”

Concordance between Antimicrobial Resistance Phenotype and Genotype of Staphylococcus pseudintermedius from Healthy Dogs

“…Interestingly, lsaE and lnuB genes were flanked by one site-specific recombinase ( Figure 3 ), which could denote a previous event of mobilization and integration in the chromosome. In fact, Yan et al described these genes in a conjugative plasmid in Enterococcus faecium, potentially transmissible to Staphylococcus aureus [ 32 ]. These analyses also identified that both genes, lsaE and lnuB were located next to an antibiotic resistance region with ant(6)-I- sat-4 -aph(3′)-III clusters [ 33 ], as described herein.…”

Genomic Insights of Enterococcus faecium UC7251, a Multi-Drug Resistant Strain From Ready-to-Eat Food, Highlight the Risk of Antimicrobial Resistance in the Food Chain

“…Additional studies have investigated that plasmids harboring linezolid resistance genes acquired from other enterococcal plasmids through MGE are associated with the MDR phenotype (Sadowy, 2018 ; Elghaieb et al, 2020 ). Conjugation of these genes was also evidenced from Enterococcus to Staphylococcus , elucidating their transmission potential (Yan et al, 2021 ). ARI3 carries two genes coding for aminoglycoside resistance ant1, apt_3 , and ant(6)-Ia , flanked by a putative recombinase and IS 4 family transposase IS Dha5 .…”