The primary goal of the proposed research is to investigate the pathogenesis and epidemiology of enteropathogenic Escherichia coli (EPEC) using molecular genetic techniques. Enteropathogenic E. coli have been defined as diarrheagenic E. coli which do not elaborate heat-labile (LT) or heat-stable (ST) enterotoxins, do not invade the intestinal mucosa and belong to certain """"""""classical"""""""" serotypes epidemiologically incriminated to be associated with infantile diarrhea. EPEC have been shown to be important causes of infantile gastroenteritis in both industrialized and developing countries. Although the exact pathogenic mechanisms of this organism are not known, recent experimental and clinical evidence indicates that adhesion of the bacterium to the intestinal mucosa is an essential step. An in vitro adhesion assay employing cultured HEp-2 cells has been described for these strains and two distinct morphologies of adherence (diffuse and localized) have been recognized. We have identified plasmids which code for the ability of the EPEC to adhere to HEp-2 cells in both morphologies and have already shown that the plasmid conferring localized adherence correlates with the ability of the parent strain to cause human diarrhea. The genes encoding both types of adherence will be cloned and specific mutants prepared to assess the importance of these factors in diarrhea. Using the cloned genes, DNA probes will be developed to diagnose EPEC in pure cultures and in stool specimens. The probes will allow us to better study the epidemiology of EPEC and to determine the epidemiologic importance of HEp-2 adhesins.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Unknown (R22)
Project #
5R22AI021657-03
Application #
3444734
Study Section
Bacteriology and Mycology Subcommittee 1 (BM)
Project Start
1986-07-01
Project End
1989-06-30
Budget Start
1988-07-01
Budget End
1989-06-30
Support Year
3
Fiscal Year
1988
Total Cost
Indirect Cost
Name
University of Maryland Baltimore
Department
Type
Schools of Medicine
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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