Education

• B.A. : Biochemistry, Case Western Reserve University, 1987-1991
• M.D. : University of Buffalo, 1992-1996
• Internship &Residency : Internal Medicine, University Hospitals of Cleveland, 1997-2000
• Chief Medical Resident : University Hospitals of Cleveland, 2000-2001
• Fellowship, Infectious Diseases, University Hospitals of Cleveland, 2001-2005

Research Interests

Colonization of the gut by pathogenic microbes often precedes the development of infection in hospitalized patients. Administration of systemic antibiotics to patients can decimate the indigenous colonic bacterial population and facilitate colonization with nosocomial pathogens.

My research is focused on mechanisms by which the (predominantly anaerobic) indigenous intestinal microbiota prevents colonization by exogenous, antibiotic-resistant, potentially pathogenic microorganisms. Within this field, I am particularly interested in the protective role played by bacterial beta-lactamase enzymes that degrade beta-lactam (penicillin-type) antibiotics within the lumen of the intestinal tract. To study this phenomenon, my laboratory uses in vitro techniques including a continuous-flow culture model of the human intestinal microbiota, as well as an in vivo mouse model of intestinal colonization. We are also beginning a clinical study to investigate this phenomenon in hospitalized patients.

I also have a secondary interest in the pathogenesis of infection and/or colonization with Staphylococcus aureus, particularly community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). In conjunction with Curtis Donskey, M.D. and Robert Bonomo, M.D., at the Cleveland VA Medical Center, my laboratory is embarking on a clinical study of colonization with CA-MRSA in our veteran population, as well as performing molecular typing of CA-MRSA isolates using a new methodology: the Diversilab rep-PCR microbial typing system.

Selected References

• pPultz, MJ, Nerandzic MM, Stiefel U, and Donskey CJ. Emergence and acquisition of fluoroquinolone-resistant gram-negative bacilli in the intestinal tracts of mice treated with fluoroquinolone antimicrobial agents. Antimicrob Agents Chemother: 52(9): 3457-60 (2008).
• Chang, S. Sethi, A.K., Eckstein, B.C., Stiefel, U., Cadnum, J.L., Donskey, C.J. Skin and Environmental Contamination with Methicillin-Resistant Staphylococcus aureus Among Carriers Identified Clinically Versus Through Active Surveillance. Clin Infect Dis: 48(10): 1423-8 (2009).
• Chang S, Sethi AK, Stiefel U, Cadnum JL, Donskey CJ. Occurrence of Skin and Environmental Contamination With Methicillin-Resistant Staphylococcus aureus Before Results of Polymerase Chain Reaction at Hospital Admission Become Available. Infect Control Hosp Epidemiol, 31(6): 607-12 (2010).
• Stiefel, U, Cadnum, JL, Eckstein, BC, Guerrero, DM, Tima, MA, and Donskey, CJ. Contamination of Hands with Methicillin-Resistant Staphylococcus aureus After Contact with Environmental Surfaces versus Skin of Colonized Patients. Infect Control Hosp Epidemiol, In press.