Howard, Susan, Ph.D.
Ph.D., Division of Virology, Dept. of Pathology, University of Cambridge, U.K., 1992.
M. Sc., Dept. of Biological Sciences, University of Windsor, Ontario, Canada, 1987.
B.Sc., (Honours, Microbiology), University of Windsor, 1984.
Gene regulation, genetics, and epidemiology of mycobacteria.
Mycobacterium abscessus is an environmental organism and a member of the rapidly-growing mycobacteria. M. abscessus can cause skin and soft tissue infections following injury or surgical procedures. It is also an emerging respiratory pathogen in cystic fibrosis patients. M. abscessus is naturally resistant to most antibiotics, but the mechanisms underlying this broad resistance are largely unknown. Additionally, little is known regarding how strains differ in their antibiotic-resistance patterns, and in the type and severity of disease they cause. Our research goals are to understand the genetic traits that influence the pathogenicity and antibiotic resistance of M. abscessus strains, and to develop rapid methods to detect the bacteria in patient samples.
M. tuberculosis, the causative agent of tuberculosis, is a slowly-growing mycobacteria and a major human pathogen. We study the regulatory factors that control the ability of M. tuberculosis to survive in human immune cells.
- Evaluation of genetic markers for differentiation of clinical isolates of M. abscessus.
- Development of rapid molecular-based detection methods for M. abscessus.
- Characterization of antibiotic-resistance genes in rapidly-growing mycobacteria.
- Defining the role of MprAB in gene regulatory networks in M. tuberculosis.
Selected Papers and Abstracts:
• Pang X, Cao G, Neuenschwander PF, Haydel SE, Hou G, Howard ST. 2011. The β-propeller gene Rv1057 of Mycobacterium tuberculosis has a complex promoter directly regulated by both the MprAB and TrcRS two-component systems. Tuberculosis (Edinb). 91 Suppl 1:S142-9.
• Klucar P, Barnes PF, Kong Y, Howard ST, Pang X, Huang FF, Tvinnereim AR, Samten B, Shams H. 2009. Vaccination strategies to enhance local immunity and protection against Mycobacterium tuberculosis. Vaccine. 27(12):1816-24.
• Wu S, Barnes PF, Samten B, Pang X, Rodrigue S, Ghanny S, Soteropoulos P, Gaudreau L, Howard ST. Microbiology. 2009. Activation of the eis gene in a W-Beijing strain of Mycobacterium tuberculosis correlates with increased SigA levels and enhanced intracellular growth. 155(Pt 4):1272-81.
•Pang X, Howard ST. 2007. Regulation of the alpha-crystallin gene acr2 by the MprAB two-component system of Mycobacterium tuberculosis. J. Bacteriology 189:6213-6221.
•Pang X, Vu P, Byrd TF, Ghanny S, Soteropoulos P, Mukamolova GV, Wu S, Samten B, Howard ST. 2007. Evidence for complex interactions of stress-associated regulons in an mprAB deletion mutant of Mycobacterium tuberculosis. Microbiology 153:1229-1242.
•Howard ST, Rhoades E, Recht J, Alsup A, Pang X, Kolter R, Lyons CR, Byrd TF. 2006. Spontaneous reversion of Mycobacterium abscessus from a smooth to a rough morphotype is associated with reduced expression of glycopeptidolipid and reacquisition of an invasive phenotype. Microbiology 2006 Jun;152(Pt 6):1581-90.
•Samten B, Howard ST, Weis SE, Wu S, Shams H, Safi H, and Barnes PF. 2005. Cyclic AMP response element-binding protein positively regulates production of IFN-gamma by T cells in response to a microbial pathogen. Journal of Immunology 174:6357-6363.
•Safi H, Barnes PF, Lakey DL, Shams H, Samten B, Vankayalapati R, Howard ST. 2004. IS 6110 functions as a mobile, monocyte-activated promoter in Mycobacterium tuberculosis. Mol. Micro. 52:999-1012.
•Talaat AM, Lyons CR, Howard ST, Johnston SA. 2004. The temporal expression profile of Mycobacterium tuberculosis in mice. Proc. Natl. Acad. Sci. 101:4602-4607.
•Wu S, Howard ST, Lakey DL, Kipnis A, Samten B, Safi H, Gruppo V, Wizel B, Shams H, Basaraba RJ, Orme IM, Barnes PF. 2004. The principal sigma factor sigA mediates enhanced growth of Mycobacterium tuberculosis strains in vivo. Mol. Micro. 51:1551-1562.
•Talaat AM, Howard ST, Hale W. 4th, Lyons R, Garner H, Johnston SA. Genomic DNA standards for gene expression profiling in Mycobacterium tuberculosis. Nucleic Acids Res 2002 Oct 15;30(20):e104.
•Howard ST, Byrd TF, Lyons CR. A polymorphic region in Mycobacterium abscessus contains a novel insertion sequence element. Microbiology 2000;148:2987-2986.