David E. Johnson, PhD
Research Associate Professor of Medicine

PhD: University of Maryland, 1976.

Phone: (410) 605-7130
Fax: (410) 605-7906
E-mail: dejohnso@umaryland.edu
Address:
Research Service (151)
VA Medical Center
10 North Greene St.
Baltimore, MD 21201

Animal models of infection.

Our interest is in the development and use of animal models of infections to assess bacterial pathogenicity factors and host defense mechanisms. The emphasis is to develop animal models that closely mimic the infection process in man. The aim of these animal studies is to provide an in vivo environment where host and pathogen interactions leading to infection or resistance can be dissected and assessed. The following animal models are available for use:

1. Infections of the Gastrointestinal Tract: an infant mouse model that can be used to assess microbial enterotoxin elaboration, microbial invasion from the GI tract and to assess antimicrobial therapy or prophylaxis; a rabbit ilial loop model, a classic model for assessment of microbial enterotoxin elaboration, can also be used to assess bacterial invasion from the GI tract, antimicrobial therapy or prophylaxis.

2. Rat Bacteremia Model: this model is designed to mimic Gram negative bacteremia that develops in the neutropenic host. Useful in assessing the efficacy of newly developed antimicrobial agents compared to existing compounds.

3. Infections of the Urinary Tract: A murine transurethral challenge model that effectively discriminates between uropathogens and non-uropathogens. The model may be used to assess the propensity of a microbial strain to induce cystitis or pyelonephritis, to assess microbial uropathogenicy factors by examining parent strains in parallel with their isogenic mutants and for the assessment of strategies for prevention of urinary tract infections. Models have been developed to assess uropathogenicity of Proteus mirabilis, E. coli, Enterococcus faecalis, Candida albicans and C. glabrata.

Cudic, M, Lockatell, C.V., Johnson, D.E., Otvos, Jr., L., "In vitro and in vivo Activity of an Antibacterial Peptide Analog Against Uropathogens", Peptides, 2003, 24:807-820.

Li, X., Lockatell, C.V., Johnson, D.E., Lane, M.C., Warren, J.W., Mobley, H.L.T., "Development of an Intranasal Vaccine to Prevent Urinary Tract Infection by Proteus mirabilis", Infection and Immunity, 2004, 72:66-75.

Heimer, S.R., Rasko, D.A., Lockatell, C.V., Johnson, D.E., Mobley, H.L.T., "Autotransporter Genes pic and tsh are Associated with Escherichia coli Strains that Cause Acute Pyelonephritis and are Expressed During Urinary Tract Infection", Infection and Immunity, 2004, 72:593-597.

Burall, L.S., Harro, J.M., Li, X., Lockatell, C.V., Himpsl, S.D., Hebel, J.R., Johnson, D.E., Mobley, H.L., "Proteus mirabilis Genes that Contribute to Pathogenesis of Urinary Tract Infection: Identification of 25 signature-tagged Mutants Attenuated at Least 100-fold", Infection and Immunity, 2004, 72:2922-2938.

Buckles, E.L, Bahrani-Mougeot, F.K., Molina, A., Lockatell, C.V., Johnson, D.E., Drachenberg, C.B., Burland, V., Blattner, F.R., Donnengerg, M.S., Identification and Characterization of a Novel Uropathogenic Escherichia coli-associated Fimbrial Gene Cluster", Infection and Immunity, 2004, 72:3890-3901.

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To contact us:

Phone: 410-706-7560
Fax: 410-706-4619
E-mail: kvardjan@ihv.umaryland.edu

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