Genetic Characterization of vanA-Enterococcus faecium Isolates from Wild Red-Legged Partridges in Portugal

Abstract

Vancomycin-resistant enterococci (VRE) have been detected in wild animals representing a public health concern. The red-legged partridge (Alectoris rufa) is a common game bird and its meat is consumed in several countries, including Portugal. Three hundred five fecal samples of red-legged partridge from the north of Portugal were screened for VRE. Samples were cultured on Slanetz-Bartley agar supplemented with vancomycin (4 mg/L) and six vanA-Enterococcus faecium were recovered. Isolates were tested for antibiotic resistance and virulence genes. Multilocus sequence typing (MLST) was performed to study the genotypic diversity of vanA-containing E. faecium. The six isolates showed erythromycin resistance and harbored the erm(B) gene and the four that were tetracycline resistant showed the tet(M) gene. The C-terminal region of the pbp5 gene of the ampicillin-resistant isolates (minimal inhibitory concentration range of 256 μg/ml) was sequenced. Two different pbp5 alleles were detected when considering the changes of amino acid in 461-629 region. All isolates harbored the esp gene, whereas hyl, together with the esp gene, was detected in five isolates. MLST analysis grouped the isolates as ST448 (n = 1), ST139 (n = 1), and ST18 (n = 4). Our findings show that the red-legged partridges could be a reservoir of antimicrobial resistance genes and may contribute to the dissemination and transference of the resistance genes to other animals and humans.

Biofilm formation capacity and presence of virulence factors among commensal Enterococcus spp. from wild birds

“…As in our results, Silva and coworkers 16 did not detect any esp genes in enterococci isolated from Partridge ( Alectoris rufa ), whereas this gene was described seven years later in six vanA -positive E. faecium isolated from the same bird species 33 . Additionally, the esp gene was found in two vanA/B2 -positive E. faecalis strains 34 .…”

Enterococci, from Harmless Bacteria to a Pathogen

“…It is important to notice that the mobile element Tn 916 /Tn 1545 -like transposon was detected in the majority of our VREar strains. This is consistent with the results from other Portuguese settings, where these mobile genetic elements were also frequently associated with acquired vancomycin resistance [ 67 , 71 ]. Moreover, it was reported, in Portugal, that human and swine share vancomycin-resistant E. faecium strains harboring Tn 1546 on indistinguishable plasmids [ 21 ].…”

“… Percentages of vancomycin-resistant enterococci reported in Portugal in different settings: food-producing animals, environmental, wastewater treatment plants, wild animals, horses, and pets [ 26 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 ]. …”

Phenotypic and Genotypic Traits of Vancomycin-Resistant Enterococci from Healthy Food-Producing Animals

“…Accordingly, a high rate of phenotypic resistance to erythromycin and tetracycline was observed among the isolates in this study. Genetically, macrolide resistance encoded by ermB and tetracycline resistance encoded by tet genes, has been linked to the transposons of the Tn1546 family that contain the vanA gene [42,45,46]. Correspondingly, erm(B), and tet(W) were frequently detected among the isolates.…”