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- Molecular evidence of the close relatedness of clinical, gull and wastewater isolates of quinolone-resistant Escherichia coliPublication . Varela, Ana Rita; Manageiro, Vera; Ferreira, Eugénia; Augusta Guimarães, M.; Costa, Paulo Martins da; Caniça, Manuela; Manaia, Célia M.Escherichia coli with reduced susceptibility to quinolones isolated from different environmental sources (urban wastewater treatment plants, n = 61; hospital effluent, n = 10; urban streams, n = 9; gulls, n = 18; birds of prey, n = 17) and from hospitalised patients (n = 28) were compared based on multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). The habitats with the most diversified genotypes of quinolone-resistant E. coli, corresponding to the highest genetic diversity (H'), were wastewater and gulls. In addition, genetically distinct populations were observed in clinical samples and birds of prey, suggesting the influence of the habitat or selective pressures on quinolone-resistant E. coli. The close genetic relatedness between isolates of clinical origin and from gulls and wastewater suggests the existence of potential routes of propagation between these sources. The most common sequence types were ST131 and ST10, with ST131 being highly specific to patients, although distributed in all of the other habitats except birds of prey. The prevalence of antimicrobial resistance was significantly higher in isolates from patients and gulls than from other sources (P < 0.01), suggesting that the effect of selective pressures met by isolates subjected to strong human impacts. The evidence presented suggests the potential circulation of bacteria between the environmental and clinical compartments, with gulls being a relevant vector of bacteria and resistance genes.
- Molecular characterization of quinolone resistance mechanisms and extended-spectrum β-lactamase production in Escherichia coli isolated from dogsPublication . Meireles, D.; Leite-Martins, L.; Bessa, L. J.; Cunha, S.; Fernandes, R.; Matos, A. de; Manaia, C. M.; Costa, P. Martins daThe increasing prevalence of antimicrobial resistances is now a worldwide problem. Investigating the mechanisms by which pets harboring resistant strains may receive and/or transfer resistance determinants is essential to better understanding how owners and pets can interact safely. Here, we characterized the genetic determinants conferring resistance to β-lactams and quinolones in 38 multidrug-resistant Escherichia coli isolated from fecal samples of dogs, through PCR and sequencing. The most frequent geno-type included the β-lactamase groups TEM (n = 5), and both TEM + CTX-M-1 (n = 5). Within the CTX-Mgroup, we identified the genes CTX-M-32, CTX-M-1, CTX-M-15, CTX-M-55/79, CTX-M-14 and CTX-M-2/44. Thirty isolates resistant to ciprofloxacin presented two mutations in the gyrA gene and one or two mutations in the par C gene. A mutation in gyr A (reported here for the first time), due to a transversion andtransition (TCG → GTG) originating a substitution of a serine by a valine in position 83 was also detected.The plasmid-encoded quinolone resistance gene, qnrs1, was detected in three isolates. Dogs can be a reservoir of genetic determinants conferring antimicrobial resistance and thus may play an important role in the spread of antimicrobial resistance to humans and other co-habitant animals.
- Quinolone-resistant Escherichia coli isolated from birds of prey in Portugal are genetically distinct from those isolated from water environments and gulls in Portugal, Spain and SwedenPublication . Vredenburg, Jana; Varela, Ana Rita; Hasan, Badrul; Bertilsson, Stefan; Olsen, Björn; Narciso-da-Rocha, Carlos; Bonnedahl, Jonas; Stedt, Johan; Costa, Paulo Martins Da; Manaia, Célia M.The influence of geographic distribution and type of habitat on the molecular epidemiology of ciprofloxacin resistant Escherichia coli was investigated. Ciprofloxacin resistant E. coli from wastewater, urban water with faecal contamination and faeces of gulls, pigeons and birds of prey, from Portugal, Spain and Sweden were compared based on multilocus sequence typing (MLST) and quinolone resistance genetic determinants. Multi-locus sequence typing allowed the differentiation of E. coli lineages associated with birds of prey from those inhabiting gulls and waters. E. coli lineages of clinical relevance, such as the complex ST131, were detected in wastewater, streams and gulls in Portugal, Spain and Sweden. Quinolone resistance was due to gyrA and parC mutations, although distinct mutations were detected in birds of prey and in wastewater, streams and gulls isolates. These differences were correlated with specific MLST lineages, suggesting resistance inheritance. Among the plasmid-mediated quinolone resistance genes, only aac(6′)-ib-cr and qnrS were detected in wastewater, streams and gulls isolates, but not in birds of prey. The horizontal transfer of the gene aac(6′)-ib-cr could be inferred from its occurrence in different MLST lineages