Molecular characterization of vancomycin-resistant enterococci and extended-spectrum β-lactamase-containingEscherichia coliisolates in wild birds from the Azores Archipelago

Abstract

To study the prevalence of vancomycin-resistant enterococci (VRE) and extended-spectrum b-lactamase (ESBL)-containing Escherichia coli isolates, and the mechanisms of resistance implicated, 220 faecal samples from wild birds were collected between 2006 and 2010 in the Azores Archipelago. Samples were spread on SlanetzÁBartley agar plates supplemented with 4 mg/l vancomycin and on Levine agar plates supplemented with 2 mg/l cefotaxime for VRE and ESBL-containing E. coli isolation, respectively. vanA-containing enterococcal isolates (four Enterococcus faecium and two Enterococcus durans) and vanC-1 Enterococcus gallinarum isolates were detected in six and seven faecal samples, respectively. VRE isolates showed ampicillin (n 011), ciprofloxacin (n 09), tetracycline (n06), erythromycin (n 05), quinupristin/dalfopristin (n 03) and high-level kanamycin resistance (n 01). The tet(L) and/or tet(M) gene was found in all tetracycline-resistant isolates and the erm(B) gene in all erythromycin-resistant isolates. Three vanAcontaining E. faecium and two E. gallinarum presented specific sequences of the Tn5397 transposon. Four VRE isolates harboured the ace virulence gene. One faecal sample revealed one ESBL-containing E. coli isolate that belongs to the A phylogenetic group, showed a phenotype of resistance to b-lactams and tetracycline, and harboured the bla CTX-M-14 , bla SHV-12 and the tet(A) genes. To our knowledge, this is the first study to focus on defining the prevalence of VRE and/or ESBL-containing E. coli strains in wild birds from the Azores. The data recovered are essential to improve knowledge about the dissemination of resistant strains through wild ecosystems and their possible implications by transferring these resistances to other animals or to humans.

Detection of vancomycin-resistant Enterococcus faecalis ST6-vanB2 and E. faecium ST915-vanA in faecal samples of wild Rattus rattus in Spain

“…Different percentages of VRE with acquired and intrinsic mechanisms have been previously found in wild animals, from no detection of VRE isolates in buzzards (Radhouani et al, 2012), and low VRE rates (2%) in Iberian wolves and lynxes up to percentages similar to the ones found in our study (about 6%) in crows and other wild birds (Oravcova et al, 2013;Silva et al, 2011). These variations may be due in part to differences in the methodologies applied and especially to difficulties in survey design when wild animals are studied.…”

“…in wild animals in percentages very variable (0-13.5%) Mallon et al, 2002;Oravcova et al, 2013Oravcova et al, , 2014Poeta et al, 2007;Radhouani et al, 2010Radhouani et al, , 2011Radhouani et al, , 2012Santos et al, 2013;Silva et al, 2011Silva et al, , 2012. The vanA gene has been detected in these studies in E. faecalis, E. faecium, E. hirae, and E. durans (Oravcova et al, 2014;Silva et al, 2011Silva et al, , 2012, being vanA-containing E. faecium the most frequent (Oravcova et al, 2013;Radhouani et al, 2010;Silva et al, 2011Silva et al, , 2012.…”

Extended-Spectrum Beta-Lactamases Producing E. coli in Wildlife, yet Another Form of Environmental Pollution?

“…Since then several reports followed (Costa et al, 2008; Poeta et al, 2008, 2009; Bonnedahl et al, 2009, 2010; Dolejska et al, 2009; Literak et al, 2009a,b, 2010; Guenther et al, 2010a,b; Hernandez et al, 2010; Pinto et al, 2010; Radhouani et al, 2010; Simoes et al, 2010; Smet et al, 2010b; Garmyn et al, 2011; Ho et al, 2011; Silva et al, 2011; Sousa et al, 2011; Wallensten et al, 2011). …”

Characterization of fecal vancomycin-resistant enterococci with acquired and intrinsic resistance mechanisms in wild animals, Spain

“…Identical resistance genes have been observed in enterococci from animals and humans, and they seem to spread freely among isolates from different reservoirs independently of their apparent host specificity [12]. At this point, wild animals play an important role, and some studies have already reported the presence of VRE and/or HLR-A enterococci in wild small mammals, rabbits, and birds [13][14][15][16].…”