RESUMO
Carbapenemase-producing bacteria cause difficult-to-treat infections related to increased mortality in health care settings. Their occurrence has been reported in raw sewage, sewage-impacted rivers, and polluted coastal waters, which may indicate their spread to the community. We assessed the variety and concentration of carbapenemase producers in coastal waters with distinct pollution levels for 1 year. We describe various bacterial species producing distinct carbapenemases not only in unsuitable waters but also in waters considered suitable for primary contact.
Assuntos
Proteínas de Bactérias/genética , Klebsiella pneumoniae/genética , Água do Mar/microbiologia , Microbiologia da Água , beta-Lactamases/genética , Acinetobacter/enzimologia , Acinetobacter/genética , Acinetobacter/isolamento & purificação , Aeromonas/enzimologia , Aeromonas/genética , Aeromonas/isolamento & purificação , Proteínas de Bactérias/classificação , Proteínas de Bactérias/metabolismo , Brasil , Citrobacter/enzimologia , Citrobacter/genética , Citrobacter/isolamento & purificação , Enterobacter/enzimologia , Enterobacter/genética , Enterobacter/isolamento & purificação , Expressão Gênica , Humanos , Isoenzimas/genética , Isoenzimas/metabolismo , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/isolamento & purificação , Kluyvera/enzimologia , Kluyvera/genética , Kluyvera/isolamento & purificação , Pseudomonas/enzimologia , Pseudomonas/genética , Pseudomonas/isolamento & purificação , Recreação , Serratia/enzimologia , Serratia/genética , Serratia/isolamento & purificação , beta-Lactamases/classificação , beta-Lactamases/metabolismoRESUMO
This study characterised the genetic environment of the chromosomally encoded bla(KLUA-9) gene from a clinical Kluyvera ascorbata isolate and performed a kinetic characterisation of KLUA-9. Purified KLUA-9 showed the highest catalytic efficacies towards benzylpenicillin, ampicillin, piperacillin, first-generation cephalosporins, cefuroxime and cefoperazone; like other 'cefotaximases', it showed a much higher rate of hydrolysis of cefotaxime than ceftazidime, whilst dicloxacillin, cefoxitin and imipenem behaved as poor substrates. A 9kb insert from K. ascorbata was cloned (Escherichia coli KK68C1) and sequenced. bla(KLUA-9) and its 266bp upstream flanking region (almost identical to the integron-associated bla(CTX-M-2)) are preceded by an aspat variant, a ypdABC-like operon and two open reading frames with unknown functions. Unlike ISCR1-associated bla(CTX-M-2) genes, we failed to detect the putative orf513 recombination sites. Instead, we were able to localise the 5bp target sites for insertion of ISEcp1B, suggesting that this element could be responsible for future (or still undetected) mobilisation of bla(KLUA-9) to more efficiently transferred elements.
Assuntos
Cefalosporinas/farmacologia , Kluyvera/enzimologia , Kluyvera/genética , beta-Lactamases/genética , Sequência de Bases , Resistência às Cefalosporinas/genética , Cefalosporinas/metabolismo , DNA Bacteriano/genética , Farmacorresistência Bacteriana/genética , Infecções por Enterobacteriaceae/microbiologia , Evolução Molecular , Genes Bacterianos , Humanos , Técnicas In Vitro , Cinética , Kluyvera/efeitos dos fármacos , Kluyvera/isolamento & purificação , Dados de Sequência Molecular , Plasmídeos/genética , beta-Lactamases/metabolismoRESUMO
Chromosomal beta-lactamase genes (bla(KLUY)) from six Kluyvera georgiana strains isolated in Guyana were cloned and expressed in Escherichia coli. KLUY-1 exhibited 100% amino acid identity with the extended-spectrum beta-lactamase CTX-M-14. We also show that a 2.7-kb Kluyvera chromosomal region exhibits 99% nucleotide identity to a portion of In60 that includes bla(CTX-M-9).
Assuntos
Proteínas de Escherichia coli/genética , Kluyvera/enzimologia , Kluyvera/genética , beta-Lactamases/genética , Sequência de Aminoácidos , Antibacterianos/farmacologia , Cromossomos Bacterianos/genética , Clonagem Molecular , Desoxirribonuclease EcoRI/química , Escherichia coli/genética , Guiana , Humanos , Kluyvera/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Dados de Sequência MolecularRESUMO
A gene identical to plasmid-borne bla(CTX-M-3) is present in the chromosome of one Kluyvera ascorbata strain. It is associated with a structure including an inverted repeat right and an open reading frame 477-like gene probably involved in the mobilization of bla(CTX-M-3). Two other K. ascorbata strains rendered the previously described bla(KLUA-9) gene.