RESUMO
Extended-spectrum beta-lactamase (ESBL) production was demonstrated in five independent, multidrug-resistant isolates of enteroaggregative Escherichia coli (EAEC) from the United Arab Emirates, representing 11.3% of the EAEC isolates recovered during 1 year. All five isolates carried the bla(CTX-M-15) and the bla(TEM-1) genes, the former positioned 48 bp downstream of an ISecp1 element. In two isolates, the bla(CTX-M-15 )and bla(TEM-1) genes were located on a 95-kb plasmid. This is the first detailed description and characterisation of ESBL production in enteroaggregative E. coli and also the first report of CTX-M-producing organisms encountered on the Arabian Peninsula.
Assuntos
Infecções por Escherichia coli/microbiologia , Escherichia coli/isolamento & purificação , Fezes/microbiologia , beta-Lactamases/biossíntese , beta-Lactamases/genética , Adulto , Pré-Escolar , Primers do DNA/química , DNA Bacteriano/química , Farmacorresistência Bacteriana Múltipla/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/enzimologia , Escherichia coli/genética , Humanos , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Plasmídeos/genética , Reação em Cadeia da Polimerase/métodos , Emirados Árabes UnidosRESUMO
One hundred and four enterotoxin producing Escherichia coli strains of wide geographical origin were tested for the expression of curli fimbriae by transmission electronmicroscopy and by ELISA using curli-specific antibodies, as well as for the presence of curli-specific gene sequences by PCR. All isolates, irrespective of the production of the fimbriae, carried sequences specific for the structure (csgA) and for one of the regulator genes (crl) of curli expression, respectively. Curli fimbriae were detected in 56 strains (53.8 %). Thirty-six strains expressed curli only when growing at 30 degrees C, 4 isolates were weakly curliated at 37 degrees C only, while on 16 strains curli was observed at both temperatures. On isolates carrying curli at both temperatures the expression of the fimbria was significantly stronger at 30 degrees C than at 37 degrees C. Curli proficiency significantly, but not completely, correlated with the binding of the Congo Red dye. The expression of curli did not confer epithelial cell invasiveness to ETEC strains but, once expressed at 30 degrees C, it facilitated the adherence of the bacteria to plastic surfaces. Curli present in more than half of the ETEC strains and expressed preferentially at low temperatures could be a factor facilitating the environmental survival of this food- and water-borne pathogen.