title: Impaired colonization by and full invasiveness of Escherichia coli K1 bearing a site-directed mutation in the type 1 pilin gene.
abstract: A type 1 pilus-deficient mutant of a systemically invasive Escherichia coli K1 strain was constructed by directed mutagenesis of pilA, the gene that codes for the major structural subunit of type 1 pili. By comparing this mutant with an isogenic pilA+ strain, we were able to assess the role of type 1 piliation in alimentary tract colonization and bloodstream invasion in neonatal rats. Intestinal colonization was not significantly affected by the pilA mutation; in contrast, loss of type 1 piliation correlated with a dramatic decrease in oropharyngeal colonization. Nevertheless, development of bacteremia after oral administration of E. coli K1 was not diminished by the mutation in pilA. Thus, loss of type 1 piliation correlated with a site-dependent effect on colonization within the alimentary tract while not interfering with bloodstream invasion.
authors.affiliation: Department of Microbiology, Pathology, and Parasitology, North Carolina State University, School of Veterinary Medicine, Raleigh 27650.
authors.forename: C A
authors.initials: CA
authors.lastname: Bloch
authors.forename: P E
authors.initials: PE
authors.lastname: Orndorff
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D003106:Colon / Q000382:microbiology; D004252:DNA Mutational Analysis; D004926:Escherichia coli / Q000235:genetics / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000382:microbiology*; D036781:Fimbriae Proteins; D010861:Fimbriae, Bacterial / Q000502:physiology*; D005798:Genes, Bacterial; D009055:Mouth / Q000382:microbiology; D010614:Pharynx / Q000382:microbiology; D051381:Rats
chemical_list: D001425:Bacterial Outer Membrane Proteins; D036781:Fimbriae Proteins