A1 Refereed original research article in a scientific journal
Fimbrial phase variation and systemic E coli infection studied in the mouse peritonitis model
Authors: Nowicki B, Vuopio-Varkila J, Viljanen P, Korhonen TK, Mäkelä PH
Publication year: 1986
Journal: Microbial Pathogenesis
Journal name in source: Microbial pathogenesis
Journal acronym: Microb Pathog
Volume: 1
Issue: 4
First page : 335
Last page: 47
Number of pages: 13
ISSN: 0882-4010
DOI: https://doi.org/10.1016/0882-4010(86)90066-5
Abstract
Mouse peritonitis induced by intraperitoneal injection of a virulent (LD50 4 x 10(5) E. coli 018:K1:H7 strain isolated from neonatal meningitis was studied. These bacteria are capable of producing both type 1 and S fimbriae, binding to mannose or sialic acid containing glycoconjugates, respectively; the production of both fimbrial types is subject to phase variation. A broth culture of the bacteria was fractionated into subpopulations containing either type 1 or S fimbriae or neither (nonfimbriated cells), and each fraction, grown in broth to logarithmic growth phase, was used to infect groups of mice. The type 1 fraction was associated with decreased virulence as the fraction was eliminated rapidly without causing a progressive infection even at 10(6) bacteria/mouse, whereas both S and nonfimbriated cells started rapid multiplication in the peritoneal cavity and spread to the blood. In nonfibriated cells, however, S fimbriae production was induced at the same time so that at 1 h after injection, 60-70% of the bacteria in the peritoneal cavity and in the blood of the mice had S fimbriae. The injected S-fimbriated fraction remained completely S-fimbriated. Rapid induction of S fimbriae also took place in vitro when the nonfimbriated bacteria were grown in mouse serum or peritoneal fluid. Anti-S serum protected the mice from a lethal dose of S-fimbriated bacteria.
Mouse peritonitis induced by intraperitoneal injection of a virulent (LD50 4 x 10(5) E. coli 018:K1:H7 strain isolated from neonatal meningitis was studied. These bacteria are capable of producing both type 1 and S fimbriae, binding to mannose or sialic acid containing glycoconjugates, respectively; the production of both fimbrial types is subject to phase variation. A broth culture of the bacteria was fractionated into subpopulations containing either type 1 or S fimbriae or neither (nonfimbriated cells), and each fraction, grown in broth to logarithmic growth phase, was used to infect groups of mice. The type 1 fraction was associated with decreased virulence as the fraction was eliminated rapidly without causing a progressive infection even at 10(6) bacteria/mouse, whereas both S and nonfimbriated cells started rapid multiplication in the peritoneal cavity and spread to the blood. In nonfibriated cells, however, S fimbriae production was induced at the same time so that at 1 h after injection, 60-70% of the bacteria in the peritoneal cavity and in the blood of the mice had S fimbriae. The injected S-fimbriated fraction remained completely S-fimbriated. Rapid induction of S fimbriae also took place in vitro when the nonfimbriated bacteria were grown in mouse serum or peritoneal fluid. Anti-S serum protected the mice from a lethal dose of S-fimbriated bacteria.
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