Randall J. Olsen, MD, PhD

Associate Professor of Clinical Pathology and Genomic Medicine, Institute for Academic Medicine
Associate Clinical Member, Research Institute
Houston Methodist
Weill Cornell Medical College

Research Lab


After completing his fellowship in hematopathology, Dr. Olsen became an Instructor in Houston Methodist Research Institute. He was recently awarded a Fellow-to-Faculty transition award from the American Heart Association to investigate virulence genetics in group A Streptococcus. The study will focus on why certain strains are more capable of causing necrotizing fasciitis, or the devastating “flesh eating” disease. He is a member of several professional societies.

Description of Research

The research in Dr. Olsen’s laboratory is focused on studying the molecular pathogenesis of invasive group A Streptococcus (GAS) infections such as necrotizing fasciitis (NF, also termed the “flesh eating infection”). During the past several years, there have been marked advances in the study of GAS genetics and epidemiology, but overall knowledge of the key molecular pathways and host-pathogen interactions mediating GAS virulence in invasive deep soft tissue infections remains largely incomplete. Previous studies in the Musser laboratory suggest that the metal transporter of the Streptococcus regulator (mtsR) regulatory gene and/or the genes under its control (the “mtsR Axis”) may play an important role in GAS NF. Dr. Olsen’s laboratory uses an integrated molecular approach to study the “mtsR Axis” in GAS NF. Affymetrix GAS gene expression microarray analysis, Luminex-based human serum protein profiling, tissue microarray examination, flow cytometric analysis, in vivo molecular imaging, quantitative microbial culture, and in vitro immunologic assays will be used for the detailed study of specimens derived from preclinical models and human patients. The long-term goal is to leverage knowledge gained to aid the development of new diagnostic tools, vaccine strategies, and therapeutic agents that will significantly improve patient care.

Areas Of Expertise

Group A Streptococcus Necrotizing fasciitis Invasive infection Pathogen-host interactions Microbial virulence
Education & Training

Clinical Fellowship , The Methodist Hospital
Residency , Baylor College of Medicine
PhD , University of Nebraska
MD , University of Nebraska Medical School, Omaha, NE
Research Fellowship , Houston Methodist Hospital

Iron efflux by PmtA is critical for oxidative stress resistance and contributes significantly to group A Streptococcus virulence
VanderWal, AR, Makthal, N, Pinochet-Barros, A, Helmann, JD, Olsen, RJ & Kumaraswami, M 2017, Infection and Immunity, vol 85, no. 6, e00091-17. DOI:

Increased pilus production conferred by a naturally occurring mutation alters hostpathogen interaction in favor of carriage in Streptococcus pyogenes
Flores, AR, Olsen, RJ, Cantu, C, Pallister, KB, Guerra, FE, Voyich, JM & Musser, JM 2017, Infection and Immunity, vol 85, no. 5, e00949-16. DOI:

A Critical Role of Zinc Importer AdcABC in Group A Streptococcus-Host Interactions During Infection and Its Implications for Vaccine Development
Makthal, N, Nguyen, K, Do, H, Gavagan, M, Chandrangsu, P, Helmann, JD, Olsen, RJ & Kumaraswami, M 2017, EBioMedicine. DOI:

Population genomic analysis of 1,777 extended-spectrum beta-lactamase-producing Klebsiella pneumoniae isolates, Houston, Texas: Unexpected abundance of clonal group 307
Long, SW , Olsen, RJ , Eagar, TN , Beres, SB, Zhao, P, Davis, JJ, Brettin, T, Xia, F & Musser, JM 2017, mBio, vol 8, no. 3, e00489-17. DOI:

Contribution of Secreted NADase and Streptolysin O to the Pathogenesis of Epidemic Serotype M1 Streptococcus pyogenes Infections
Zhu, L, Olsen, RJ, Lee, JD, Porter, AR, DeLeo, FR & Musser, JM 2017, American Journal of Pathology. DOI:

Population genomic analysis of 1,777 extended-spectrum beta-lactamase-producing Klebsiella pneumoniae isolates, Houston, Texas: Unexpected abundance of clonal group 307
Long, SW , Olsen, RJ , Eagar, TN , Beres, SB, Zhao, P, Davis, JJ, Brettin, T, Xia, F & Musser, JM 2017, mBio, vol 8, no. 3, e00489-17. DOI:

Case Series Description and Genomic Characterization of Invasive Group A Streptococcal Infections in Pediatric Patients
Bard, JD, Mongkolrattanothai, K, Kachroo, P, Beres, S & Olsen, RJ 2016, Pediatric Infectious Disease Journal. DOI:

Genomic Landscape of Intrahost Variation in Group A Streptococcus: Repeated and Abundant Mutational Inactivation of the fabT Gene Encoding a Regulator of Fatty Acid Synthesis
Eraso, JM, Olsen, RJ, Beres, SB, Kachroo, P, Porter, AR, Nasser, W, Bernard, PE, DeLeo, FR & Musser, JM 2016, Infection and Immunity, vol 84, no. 12, pp. 3268-3281. DOI:

A prospective observational cohort study in primary care practices to identify factors associated with treatment failure in Staphylococcus aureus skin and soft tissue infections
Lee, GC, Hall, RG, Boyd, NK, Dallas, SD, Du, LC, Treviño, LB, Treviño, SB, Retzloff, C, Lawson, KA, Wilson, J, Olsen, RJ, Wang, Y & Frei, CR 2016, Annals of Clinical Microbiology and Antimicrobials, vol 15, no. 1, 58. DOI:

Predictors of community-associated Staphylococcus aureus, methicillin-resistant and methicillin-susceptible Staphylococcus aureus skin and soft tissue infections in primary-care settings
LEE, GC, HALL Hall, RG, BOYD, NK, DALLAS, SD, DU, LC, TREVIÑO, LB, RETZLOFF, C, TREVIÑO, SB, LAWSON, KA, WILSON, JP, OLSEN, RJ, WANG, Y & FREI, CR 2016, Epidemiology and Infection, pp. 1-7. DOI:

Increased use of surgical energy promotes methicillin-resistant Staphylococcus aureus colonization in rabbits following open ventral hernia mesh repair
Fernandez-Moure, JS, van Eps, JL, Peress, L, Cantu, C, Olsen, RJ, Jenkins, L, Cabrera, FJ, Tasciotti, E, Weiner, BK & Dunkin, BJ 2016, Surgical Endoscopy and Other Interventional Techniques, pp. 1-9. DOI:

Next-generation sequencing of matched primary and metastatic rectal adenocarcinomas demonstrates minimal mutation gain and concordance to colonic adenocarcinomas
Crumley, SM, Pepper, KL, Phan, AT, Olsen, RJ, Schwartz, MR & Portier, BP 2016, Archives of Pathology and Laboratory Medicine, vol 140, no. 6, pp. 529-535. DOI:

Intergenic variable-number tandem-repeat polymorphism upstream of rocA alters toxin production and enhances virulence in Streptococcus pyogenes
Zhu, L, Olsen, RJ, Horstmann, N, Shelburne, SA, Fan, J, Hu, T & Musser, JM 2016, Infection and Immunity, vol 84, no. 7, pp. 2086-2093. DOI:

Integrating rapid diagnostics and antimicrobial stewardship in two community hospitals improved process measures and antibiotic adjustment time
Lockwood, AM, Perez, KK, Musick, WL, Ikwuagwu, JO, Attia, E, Fasoranti, OO, Cernoch, PL, Olsen, RJ & Musser, JM 2016, Infection Control and Hospital Epidemiology, vol 37, no. 4, pp. 425-432. DOI:

Structural and functional analysis of RopB: A major virulence regulator in Streptococcus pyogenes
Makthal, N, Gavagan, M, Do, H, Olsen, RJ, Musser, JM & Kumaraswami, M 2016, Molecular Microbiology, vol 99, no. 6, pp. 1119-1133. DOI:

Transcriptome remodeling contributes to epidemic disease caused by the human pathogen Streptococcus pyogenes
Beres, SB, Kachroo, P, Nasser, W, Olsen, RJ, Zhu, L, Flores, AR, de la Riva, I, Paez-Mayorga, J, Jimenez, FE, Cantu, C, Vuopio, J, Jalava, J, Kristinsson, KG, Gottfredsson, M, Corander, J, Fittipaldi, N, Di Luca, MC, Petrelli, D, Vitali, LA, Raiford, A, Jenkins, L & Musser, JM 2016, mBio, vol 7, no. 3, e00403-16. DOI:

Musser et al. Reply to “emergence of the same successful clade among distinct populations of emm89 streptococcus pyogenes in multiple geographic regions”
Musser, JM, Zhu, L, Olsen, RJ & Nasser, W 2015, mBio, vol 6, no. 6, e01838-15. DOI:

Adhesin competence repressor (AdcR) from Streptococcus pyogenes controls adaptive responses to zinc limitation and contributes to virulence
Sanson, M, Makthal, N, Flores, AR, Olsen, RJ, Musser, JM & Kumaraswami, M 2015, Nucleic Acids Research, vol 43, no. 1, pp. 418-432. DOI:

A molecular trigger for intercontinental epidemics of group A Streptococcus
Zhu, L, Olsen, RJ, Nasser, W, Beres, SB, Vuopio, J, Kristinsson, KG, Gottfredsson, M, Porter, AR, DeLeo, FR & Musser, JM 2015, The Journal of clinical investigation, vol 125, no. 9, pp. 3545-3559. DOI:

Haemagglutinin mutations and glycosylation changes shaped the 2012/13 influenza A(H3N2) epidemic, Houston, Texas
Stucker, KM, Schobel, SA, Olsen, RJ, Hodges, HL, Lin, X, Halpin, RA, Fedorova, N, Stockwell, TB, Tovchigrechko, A, Das, SR, Wentworth, DE & Musser, JM 2015, Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin, vol 20, no. 18.