title: Adaptation of signature-tagged mutagenesis to Escherichia coli K1 and the infant-rat model of invasive disease.
abstract: With the exception of the polysialic acid capsule (K1 antigen), little is known about other virulence factors needed for systemic infection by Escherichia coli K1, the leading cause of Gram-negative neonatal meningitis in humans. In this work, the functional genomics method of signature-tagged mutagenesis (STM) was adapted to E. coli K1 and the infant-rat model to identify non-capsule virulence genes. Validation of the method was demonstrated by the failure to recover a reconstructed acapsular mutant from bacterial pools used to systemically infect 5-day-old rats. Three new genes required for systemic disease were identified from a total of 192 mutants screened by STM (1.56% hit rate). Gut colonization, Southern blot hybridization, mixed-challenge infection, and DNA sequence analyses showed that the attenuating defects in the mutants were associated with transposon insertions in rfaL (O antigen ligase), dsbA (thiol:disulfide oxidoreductase), and a new gene, puvA (previously unidentified virulence gene A), with no known homologues. The results indicate the ability of STM to identify novel systemic virulence factors in E. coli K1.
authors: Department of Pathobiology, University of Illinois at Urbana-Champaign, 61802, USA.
authors: M D
authors: MD
authors: Gonzalez
authors: C A
authors: CA
authors: Lichtensteiger
authors: E R
authors: ER
authors: Vimr
mesh_terms: D000818:Animals; D015139:Blotting, Southern; D004195:Disease Models, Animal; D004926:Escherichia coli / Q000235:genetics* / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000382:microbiology / Q000503:physiopathology*; D006801:Humans; D007231:Infant, Newborn; D016920:Meningitis, Bacterial / Q000382:microbiology; D016296:Mutagenesis; D051381:Rats; D017422:Sequence Analysis, DNA; D013154:Spleen / Q000382:microbiology; D014774:Virulence / Q000235:genetics