Enteropathogenic Escherichia coli (EPEC) are a significant cause of infantile diarrhea. The long-term objectives of this project are to study the pathogenesis of disease due to this organism and to develop DNA probes for diagnosis and vaccine candidates for prevention. Recent evidence indicates that the pathogenesis of EPEC is a two-stage process. Stage 1 involves plasmid-mediated adherence factors which are responsible for the intimate adherence of the bacteria to the microvilli resulting in the characteristic EPEC histopathology. The features of the EPEC lesion include effacement and dissolution of the brush border along with dense condensation of actin microfilaments in the enterocyte cytoplasm directly beneath the adherent bacterium. Similar to the multiple possible colonization factors in human and animal enterotoxigenic E. coli, there appear to be multiple factors responsible for stage 1 adherence in EPEC. At least two such factors (class I and class II adhesins) are found in strains pathogenic for humans and a third factor may be present in strains pathogenic for rabbits (RDEC-1). The chromosomal factor responsible for stage 2 brush border effacement and actin condensation (Actin Condensation Factor, ACF) appears to be common for all EPEC. The primary goal of the proposed research is to investigate the pathogenesis of EPEC using molecular genetic techniques. The genes encoding the ACF will be cloned, sequenced, and mutated and the gene products and regulation of genes encoding the plasmid-borne class I adhesin will be studied. A DNA probe to detect the ACF will be developed and evaluated using isolates from an ongoing epidemiological study of infant diarrhea in Santiago, Chile. The genes encoding the class II adhesin will be mutated and a DNA probe developed and evaluated for this factor. The interaction of plasmid and chromosomal virulence factors will be studied using tissue culture and rabbit models. Finally, attenuated vaccine candidates will be developed for the class I EPEC by deleting the genes for the ACF while retraining the genes for the initial class I adhesions.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Unknown (R22)
Project #
2R22AI021657-04
Application #
3565479
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Project Start
1986-07-01
Project End
1994-06-30
Budget Start
1989-07-01
Budget End
1990-06-30
Support Year
4
Fiscal Year
1989
Total Cost
Indirect Cost
Name
University of Maryland Baltimore
Department
Type
DUNS #
003255213
City
Baltimore
State
MD
Country
United States
Zip Code
21201
Boisen, Nadia; Hansen, Anne-Marie; Melton-Celsa, Angela R et al. (2014) The presence of the pAA plasmid in the German O104:H4 Shiga toxin type 2a (Stx2a)-producing enteroaggregative Escherichia coli strain promotes the translocation of Stx2a across an epithelial cell monolayer. J Infect Dis 210:1909-19
Levine, Jonathan A; Hansen, Anne-Marie; Michalski, Jane M et al. (2014) H-NST induces LEE expression and the formation of attaching and effacing lesions in enterohemorrhagic Escherichia coli. PLoS One 9:e86618
Hansen, Anne-Marie; Chaerkady, Raghothama; Sharma, Jyoti et al. (2013) The Escherichia coli phosphotyrosine proteome relates to core pathways and virulence. PLoS Pathog 9:e1003403
Steyert, Susan R; Kaper, James B (2012) Contribution of urease to colonization by Shiga toxin-producing Escherichia coli. Infect Immun 80:2589-600
Lodato, Patricia B; Hsieh, Ping-Kun; Belasco, Joel G et al. (2012) The ribosome binding site of a mini-ORF protects a T3SS mRNA from degradation by RNase E. Mol Microbiol 86:1167-82
Steyert, Susan R; Rasko, David A; Kaper, James B (2011) Functional and phylogenetic analysis of ureD in Shiga toxin-producing Escherichia coli. J Bacteriol 193:875-86
Hansen, Anne-Marie; Kaper, James B (2009) Hfq affects the expression of the LEE pathogenicity island in enterohaemorrhagic Escherichia coli. Mol Microbiol 73:446-65
Lodato, Patricia B; Kaper, James B (2009) Post-transcriptional processing of the LEE4 operon in enterohaemorrhagic Escherichia coli. Mol Microbiol 71:273-90
Saldana, Zeus; Erdem, Aysen L; Schuller, Stephanie et al. (2009) The Escherichia coli common pilus and the bundle-forming pilus act in concert during the formation of localized adherence by enteropathogenic E. coli. J Bacteriol 191:3451-61
SaldaƱa, Zeus; Xicohtencatl-Cortes, Juan; Avelino, Fabiola et al. (2009) Synergistic role of curli and cellulose in cell adherence and biofilm formation of attaching and effacing Escherichia coli and identification of Fis as a negative regulator of curli. Environ Microbiol 11:992-1006

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