Affiliation:
1. Laboratoire d'Études de Génétique Bactérienne dans les Infections de l'Enfant (EA 3105), Université Denis Diderot-Paris 7,1 and
2. INSERM U 411, Faculté de Médecine Necker-Enfants Malades, 75730 Paris cedex 15,2 and
3. Centre d'Etude du Polymorphisme Humain, 75010 Paris,3 France
4. INSERM U 458,4 Hôpital Robert Debré, 75395 Paris cedex 19,
Abstract
ABSTRACT
Specific virulence factors associated with the pathogenesis of
Escherichia coli
strains causing neonatal meningitis (ECNM), such as the K1 capsular polysaccharide, the S fimbriae, and the Ibe10 protein, have been previously identified. However, some other yet unidentified factors are likely to be involved in the pathogenesis of ECNM. To identify specialized unique DNA regions associated with ECNM virulence, we used the representational difference analysis technique. The genomes of two strains belonging to nonpathogenic phylogenetic group A of the ECOR reference collection were subtracted from
E. coli
strain C5, isolated from a case of neonatal meningitis. Strain C5 belongs to the phylogenetic group B2 as do the majority of ECNM. We have isolated and mapped 64 DNA fragments which are specific for strain C5 and not found in nonpathogenic strains. Of these clones, 44 were clustered in six distinct regions on the chromosome. The
sfa
and
ibe10
genes were located in regions 2 and 6, respectively. A group of genes (
cnf1
,
hra
,
hly
, and
prs
) known to be present in a pathogenicity island of the uropathogenic strain
E. coli
J96 colocalized with region 6. The occurrence of these DNA regions was tested in a set of meningitis-associated strains and in a control group composed of non-meningitis-associated strains belonging to the same B2 group. Regions 1, 3, and 4 were present in 91, 82, and 81%, respectively, of the meningitis strains and in 40, 13, and 47% of the control strains. Together, these data suggest that regions 1, 3, and 4 code for factors associated with the ability of
E. coli
to invade the meninges of neonates.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Immunology,Microbiology,Parasitology