Draft genome sequences of clinical mastitis-associated Enterococcus faecalis and Enterococcus faecium carrying multiple antimicrobial resistance genes isolated from dairy cows

Abstract

ObjectivesThe emergence of antimicrobial-resistant and mastitis-associated Enterococcus faecalis and Enterococcus faecium is of great concern due to the huge economic losses associated with enterococcal infections. Here we report the draft genome sequences of Enterococcus faecalis and Enterococcus faecium strains which were isolated from raw milk samples obtained from mastitis-infected cows in Bangladesh. MethodsStrains were isolated, identified and Genomic DNA was sequenced using Illumina NextSeq 550 platform. The assembled contigs were analyzed for virulence, antimicrobial resistance genes, and multi-locus sequence type. The genomes were compared to previously reported Enterococcus faecalis and Enterococcus faecium genomes to generate core genome phylogenetic trees. ResultsEnterococcus faecalis strain BR-MHR218Efa and Enterococcus faecium strain BR-MHR268Efe belonged to multilocus sequence type ST-190 and ST-22, respectively. Both sequence types seem to represent relatively rare sequence types. BR-MHR268Efe harbored only one antibiotic resistance gene encoding resistance towards macrolides (lsa(A)), while BR-MHR218Efa harbored ten different antibiotic resistance genes encoding resistance to aminoglycosides (ant[6]-Ia, aph(3′)-III), sulphonamides (aac(6′)-II), lincosamides (lnu(B)), macrolides (erm(B)), MLSB antibiotics (msr(C)), tetracyclines (tet(M), tet(L)), trimethoprim (dfrG) and pleuromutilin-lincosamide-streptogramin A (lsa(E)).The virulence gene composition was different in the two isolates. BR-MHR218Efa harbored only two virulence genes involved in adherence (acm, scm). BR-MHR268Efe harbored eight complete virulence operons including three operons involved in adherence (Ace, Ebp pili, EfaA), two operons involved in biofilm formation (BopD, Fsr) and three exoenzymes (gelatinase, hyaluronidase, SprE). ConclusionsThe genome sequences of strains BR-MHR268Efe and BR-MHR218Efa will serve as a reference point for molecular epidemiological studies of mastitis-associated Enterococcus faecalis and Enterococcus faecium. Additionally, the findings will help the understand the complex antimicrobial resistant livestock Enterococci.