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The CTX-M beta-lactamase pandemic.
Cantón, Rafael; Coque, Teresa M.
Afiliação
  • Cantón R; Servicio de Microbiología, Hospital Ramón y Cajal, 28034-Madrid, Spain.
Curr Opin Microbiol ; 9(5): 466-75, 2006 Oct.
Article em En | MEDLINE | ID: mdl-16942899
In the past decade CTX-M enzymes have become the most prevalent extended-spectrum beta-lactamases, both in nosocomial and in community settings. The insertion sequences (ISs) ISEcp1 and ISCR1 (formerly common region 1 [CR1] or orf513) appear to enable the mobilization of chromosomal beta-lactamase Kluyvera species genes, which display high homology with blaCTX-Ms. These ISs are preferentially linked to specific genes: ISEcp1 to most blaCTX-Ms, and ISCR1 to blaCTX-M-2 or blaCTX-M-9. The blaCTX-M genes embedded in class 1 integrons bearing ISCR1 are associated with different Tn402-derivatives, and often with mercury Tn21-like transposons. The blaCTX-M genes linked to ISEcp1 are often located in multidrug resistance regions containing different transposons and ISs. These structures have been located in narrow and broad host-range plasmids belonging to the same incompatibility groups as those of early antibiotic resistance plasmids. These plasmids frequently carry aminoglycoside, tetracycline, sulfonamide or fluoroquinolone resistance genes [qnr and/or aac(6')-Ib-cr], which would have facilitated the dissemination of blaCTX-M genes because of co-selection processes. In Escherichia coli, they are frequently carried in well-adapted phylogenetic groups with particular virulence-factor genotypes. Also, dissemination has been associated with different clones (CTX-M-9 or CTX-M-14 producers) or epidemic clones associated with specific enzymes such as CTX-M-15. All these events might have contributed to the current pandemic CTX-M beta-lactamase scenario.
Assuntos
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Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Bactérias / Infecções Bacterianas / Beta-Lactamases Limite: Humans Idioma: En Ano de publicação: 2006 Tipo de documento: Article
Buscar no Google
Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Bactérias / Infecções Bacterianas / Beta-Lactamases Limite: Humans Idioma: En Ano de publicação: 2006 Tipo de documento: Article