Wild birds as biological indicators of environmental pollution: antimicrobial resistance patterns of Escherichia coli and enterococci isolated from common buzzards (Buteo buteo)

Abstract

Center of Collecting, Welcome and Handling of Wild Animals (CRATAS), University of Trá s-os-Montes and Alto Douro, Vila Real, PortugalA total of 36 Escherichia coli and 31 enterococci isolates were recovered from 42 common buzzard faecal samples. The E. coli isolates showed high levels of resistance to streptomycin and tetracycline. The following resistance genes were detected: bla TEM (20 of 22 ampicillin-resistant isolates), tet(A) and/or tet(B) (16 of 27 tetracycline-resistant isolates), aadA1 (eight of 27 streptomycin-resistant isolates), cmlA (three of 15 chloramphenicol-resistant isolates), aac(3)-II with/without aac(3)-IV (all seven gentamicin-resistant isolates) and sul1 and/or sul2 and/or sul3 [all eight sulfamethoxazole/trimethoprim-resistant (SXT) isolates]. intI1 and intI2 genes were detected in four SXT-resistant isolates. The virulence-associated genes fimA (type 1 fimbriae), papC (P fimbriae) and aer (aerobactin) were detected in 61.1, 13.8 and 11.1 % of the isolates, respectively. The isolates belonged to phylogroups A (47.2 %), B1 (8.3 %), B2 (13.9 %) and D (30.5 %). For the enterococci isolates, Enterococcus faecium was the most prevalent species (48.4 %). High levels of tetracycline and erythromycin resistance were found among our isolates (87 and 81 %, respectively). Most of the tetracycline-resistant strains carried the tet(M) and/or tet(L) genes. The erm(B) gene was detected in 80 % of erythromycin-resistant isolates. The vat(D) and/or vat(E) genes were found in nine of the 17 quinupristin-dalfopristin-resistant isolates. The enterococcal isolates showing high-level resistance for kanamycin, gentamicin and streptomycin contained the aph(39)-IIIa, aac(69)-aph(20) and ant(6)-Ia genes, respectively. This report reveals that common buzzards seem to represent an important reservoir, or at least a source, of multiresistant E. coli and enterococci isolates, and consequently may represent a considerable hazard to human and animal health by transmission of these isolates to waterways and other environmental sources via their faecal deposits.

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.…”

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

“…The presence of vanA in other wild mammals, such as woodmice (Apodemus sylvaticus), black rats (Rattus rattus), or badgers (Meles meles), has been previously reported [13,25]. This gene has also been identified in wild birds and amphibians [26][27][28][29][30][31]. Resistance mediated by vanA is characterized by high levels of resistance to glycopeptides; our isolate showed a high MIC value to vancomycin (>256 μg/mL) and teicoplanin (128 μg/mL).…”

Antibiotic resistance assessment in bacteria isolated in migratory Passeriformes transiting through the Metaponto territory (Basilicata, Italy)

“…Birds not only acquire pathogens from the environment, but also return them via excretion, potentially facilitating the dissemination of pathogenic organisms to both humans and other animals, especially through water (Benskin et al 2009;Wellington et al 2013). However, further epidemiological studies are necessary to gain a more detailed understanding of the transmission modality of resistant bacteria to wild birds and their spreading into the environment (Guenther et al 2010;Radhouani et al 2012).…”

“…Resistant bacteria of human and veterinary origin are believed to be transmitted to wild birds through contaminated food or water (Abulreesh et al 2007;Bonnedahl et al 2009;Guenther et al 2010;Radhouani et al 2012). …”