Genotypic and phenotypic characterization of attaching and effacing Escherichia coli (AEEC) isolated from children with and without diarrhoea in Londrina, Brazil.
Attaching and effacing Escherichia coli (AEEC) have been implicated in diarrhoea in humans in several countries. A total of 919 E. coli strains, isolated from 125 children with diarrhoea and 98 without diarrhoea, was investigated by PCR for the presence of the EAF, bfp, eae and stx genes. Thirty-four of these isolates were found to carry the eae gene; they were isolated from 27 (79.4 %) children with diarrhoea and seven (20.6 %) controls, in the city of Londrina, Brazil. These strains were investigated for their genotypic and phenotypic characteristics. Different genetic profiles were observed; strains containing the eae gene alone were most common (47.1 %). The characteristic genetic profile of typical enteropathogenic E. coli (EPEC), eae, bfp and EAF, was only found in isolates from children with diarrhoea. The stx gene was not detected in any of the 34 strains studied. Ten (29.4 %) strains were negative in the fluorescent actin-staining test. Localized adhesion (LA) was the most common pattern of adhesion (44.1 %), followed by the aggregative adhesion (AA) (23.5 %) and localized adhesion-like (LAL) (14.7 %) patterns. The results showed a strong association between strains presenting the LA pattern and diarrhoea. Forty-seven per cent of the strains studied belonged to classical O-serogroups of EPEC. The most common serotype found was O119 : H6; these isolates all showed the LA pattern, were positive for fluorescent actin-staining and were associated with diarrhoea. Intimin beta was detected in seven strains, four of which belonged to serotype O119 : H6 and three to serotype ONT : H7; all were associated with diarrhoea. On the other hand, intimin epsilon was detected in two strains of serotype O111 : H38 and one of serotype ONT : H19, isolated from children without diarrhoea. To our knowledge, this is the first report of the occurrence of intimin epsilon in strains of E. coli isolated from humans in Brazil.
Departamento de Microbiologia, Universidade Estadual de Londrina, Londrina, PR, Brazil 2Instituto Adolfo Lutz, São Paulo, SP, Brazil#dReceived 29 May 2002 Accepted 12 February 2003.
Eliane Blanco
EB
Nunes
Departamento de Microbiologia, Universidade Estadual de Londrina, Londrina, PR, Brazil 2Instituto Adolfo Lutz, São Paulo, SP, Brazil#dReceived 29 May 2002 Accepted 12 February 2003.
Halha Ostrensky
HO
Saridakis
Departamento de Microbiologia, Universidade Estadual de Londrina, Londrina, PR, Brazil 2Instituto Adolfo Lutz, São Paulo, SP, Brazil#dReceived 29 May 2002 Accepted 12 February 2003.
Kinue
K
Irino
Departamento de Microbiologia, Universidade Estadual de Londrina, Londrina, PR, Brazil 2Instituto Adolfo Lutz, São Paulo, SP, Brazil#dReceived 29 May 2002 Accepted 12 February 2003.
Jacinta Sanchez
JS
Pelayo
D018829:Adhesins, Bacterial / Q000235:genetics; D001422:Bacterial Adhesion / Q000235:genetics; D001938:Brazil; D002352:Carrier Proteins / Q000235:genetics; D002648:Child; D003967:Diarrhea / Q000382:microbiology*; D004926:Escherichia coli / Q000145:classification* / Q000235:genetics / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000235:genetics; D036781:Fimbriae Proteins / Q000235:genetics; D005838:Genotype; D006460:Hemolysin Proteins / Q000096:biosynthesis; D006801:Humans; D010641:Phenotype; D022621:Shiga Toxin / Q000235:genetics
D018829:Adhesins, Bacterial; C104901:BfpA protein, E coli; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D006460:Hemolysin Proteins; C073819:eaeA protein, E coli; D036781:Fimbriae Proteins; D022621:Shiga Toxin