Jeffrey M. Rybak, PharmD, PhD
Jeffrey M. Rybak, PharmD, PhD

Jeffrey M. Rybak, PharmD, PhD

Assistant Member, St. Jude Faculty

Departments

Education

Postdoctoral Fellowship – College of Pharmacy, University of Tennessee Health Science Center Memphis, Tennessee
PhD – College of Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, Tennessee
Infectious Diseases PGY2 Residency – University of Kentucky Healthcare, Lexington, KY 
Pharmacy Practice PGY1 Residency – University of Kentucky Healthcare, Lexington, KY 
PharmD - Eugene Applebaum College of Pharmacy, Detroit, Michigan

Honors & Awards

  • 2019  Society of Infectious Diseases Pharmacists Young Investigator Research Award Grant
  • 2017  American College of Clinical Pharmacy Research Institute Futures Grant Junior Investigator Award

Research Interests

While new and difficult-to-treat fungal pathogens are emerging, and the number of patients at-risk for developing infections caused by these pathogens is rising, treatment options for these patients remain severely limited and relatively few tools exist to enable the study of these potentially deadly pathogens. The long-term goal of my research program is to improve the treatment of pediatric patients with invasive fungal infections through the identification of factors contributing to therapeutic failures and the development of novel therapeutic strategies to combat fungal pathogens. Our laboratory studies a variety of fungal pathogens recognized as the greatest threats to global public health, including Candidozyma (Candida) auris, Aspergillus fumigatus, and Mucoralean molds, and is involved in three related areas of research:

  • Revealing the genetic and molecular determinants of antifungal treatment failures
  • Discovery of therapeutic strategies to overcome difficult-to-treat fungal pathogens
  • Creation of novel genetic and molecular tools to advance the study of pathogenic fungi

Contact Information

Jeffrey M. Rybak, PharmD, PhD Pharmacy and Pharmaceutical Sciences MS 313, Room I5304 St. Jude Children's Research Hospital 262 Danny Thomas Place Memphis, TN 38105-3678

St. Jude Faculty List

Selected Publications

Carolus H, Sofras D, Boccarella G, Sephton-Clark P, Biriukov V, Cauldron NC, Romero CL, Vergauwen R, Yazdani S, Pierson S, Jacobs S, Vandecruys P, Wijnants, Meis JF, Gabaldon T, van den Berg P, Rybak JM, Cuomo CA, Van Dijck P. Acquired amphotericin B resistance leads to fitness trade-offs that can be mitigated by compensatory evolution in Candida auris. Nat Microbiol 2024 Dec;9(12):3304-3320. doi: 10.1038/s41564-024-01854-z. PMID: 39567662.

Xie J, Rybak JM, Martin-Vicente A, Guruceaga X, Thorn HI, Nywening AV, Ge W, Parker JE, Kelly SL, Rogers PD, Fortwendel JR. The sterol C-24 methyltransferase encoding gene, erg6, is essential for viability of Aspergillus species. Nat Commun 2024 May 20;15(1):4261. doi: 10.1038/s41467-024-48767-3. PMID: 38769341.

Bergin S, Doorley LA, Rybak JM, Wolfe KH, Butler G, Cuomo CA, Rogers PD. Analysis of clinical Candida parapsilosis isolates reveals copy number variation in key fluconazole resistance genes. Antimicrob Agents Chemother 2024 Jun 5;68(6):e0161923. doi: 10.1128/aac.01619-23. PMID: 38712935.

Rybak JM, Xie J, Martin-Vicente A, Guruceaga X, Thorn HI, Nywening AV, Ge W, Souza ACO, Shetty AC, McCracken C, Bruno VM, Parker JE, Kelly SL, Snell HM, Cuomo CA, Rogers PD, Fortwendel JR. A novel secondary mechanism of action for triazole antifungals: negative feedback regulation of HMG-CoA Reductase. Nat Commun 2024 Apr 29;15(1):3642. doi: 10.1038/s41467-024-48029-2. PMID: 38684680; PMCID: PMC11059170.

Zhou Y, Phelps GA, Mangrum MM, McLeish J, Phillips EK, Lou J, Ancajas CF, Rybak JM, Oelkers PM, Lee RE, Best MD, Reynolds TB. The small molecule CBR-5884 inhibits the Candida albicans phosphatidylserine synthase. mBio 2024 May 8;15(5):e0063324. doi: 10.1128/mbio.00633-24. PMID: 38587428; PMCID: PMC11077991.

Doorely LA, Barker KS, Zhang Q, Rybak JM, Rogers PD. Combination of CpTAC1 and CpERG11 mutations lead to high level triazole resistance in Candida parapsilosis. Clin Microbiol Infect. 2023 Dec;29(12):1602.e1-1602.e7. doi: 10.1016/j.cmi.2023.08.030. Epub 2023 Sep 4. PMID: 37666448

Souza ACO, Ge W, Wiederhold NP, Rybak JM, Fortwendel JR, Rogers PD. hapE and hmg1 Mutations Are Drivers of cyp51A-Independent Pan-Triazole Resistance in an Aspergillus fumigatus Clinical Isolate. Microbiol Spectr 2023 May 4:e0518822. doi:10.1128/spectrum.05188-22. Epub ahead of print. PMID: 37140376

Rybak JM, Cuomo CA, David Rogers P. The molecular and genetic basis of antifungal resistance in the emerging fungal pathogen Candida auris. Curr Opin Microbiol 2022 Dec;70:102208. doi: 10.1016/j.mib.2022.102208. Epub 2022 Oct 12. PMID: 36242897.

Doorley LA, Rybak JM, Berkow EL, Zhang Q, Morschhäuser J, Rogers PD. Candida parapsilosis Mdr1B and Cdr1B Are Drivers of Mrr1-Mediated Clinical Fluconazole Resistance. Antimicrob Agents Chemother 2022 Jul 19;66(7):e0028922. doi: 10.1128/aac.00289-22. Epub 2022 Jun 14. PMID: 35699442

Liu J, Vogel AK, Miao J, Carnahan JA, Lowes DJ, Rybak JM, Peters BM. Rapid Hypothesis Testing in Candida albicans Clinical Isolates Using a Cloning-Free, Modular, and Recyclable System for CRISPR-Cas9 Mediated Mutant and Revertant Construction. Microbiol Spectr 2022 May 25:e0263021. doi: 10.1128/spectrum.02630-21. PMID: 35612314.

Rybak JM, Barker KS, Muñoz JF, Parker JE, Ahmad S, Mokaddas E, Abdullah A, Elhagracy RS, Kelly SL, Cuomo CA, Rogers PD. In vivo emergence of high-level resistance during treatment reveals the first identified mechanism of amphotericin B resistance in Candida auris. Clin Microbiol Infect 2022 Jun;28(6):838-843. doi: 10.1016/j.cmi.2021.11.024. Epub 2021 Dec 13. PMID: 34915074.

Rybak JM, Sharma C, Doorley LA, Barker KS, Palmer GE, Rogers PD. Delineation of the Direct Contribution of Candida auris ERG11 Mutations to Clinical Triazole Resistance. Microbiol Spectr 2021 Dec 22;9(3):e0158521. doi: 10.1128/Spectrum.01585-21. Epub 2021 Dec 8. PMID: 34878305; PMCID: PMC8653815.

Nywening AV, Rybak JM, Rogers PD, Fortwendel JR. Mechanisms of triazole resistance in Aspergillus fumigatus. Environ Microbiol 2020 Oct 12. doi: 10.1111/1462-2920.15274. PMID: 33047482.

Rybak JM, Muñoz JF, Barker KS, Parker JE, Esquivel BD, Berkow EL, Lockhart SR, Gade L, Palmer GE, White TC, Kelly SL, Cuomo CA, Rogers PD. Mutations in TAC1B: a Novel Genetic Determinant of Clinical Fluconazole Resistance in Candida auris. mBio 2020 May 12;11(3):e00365-20. doi: 10.1128/mBio.00365-20. PMID: 32398311; PMCID: PMC7218281.

Esquivel BD, Rybak JM, Barker KS, Fortwendel JR, Rogers PD, White TC. Characterization of the Efflux Capability and Substrate Specificity of Aspergillus fumigatus PDR5-like ABC Transporters Expressed in Saccharomyces cerevisiae. mBio 2020 Mar 24;11(2):e00338-20. doi: 10.1128/mBio.00338-20. PMID: 32209680; PMCID: PMC7157516.

Rybak JM, Ge W, Wiederhold NP, Parker JE, Kelly SL, Rogers PD, Fortwendel JR. Mutations in hmg1, Challenging the Paradigm of Clinical Triazole Resistance in Aspergillus fumigatus. mBio. 2019 Apr 2;10(2):e00437-19. doi: 10.1128/mBio.00437-19. PMID: 30940706; PMCID: PMC6445940.

Rybak JM, Doorley LA, Nishimoto AT, Barker KS, Palmer GE, Rogers PD. Abrogation of Triazole Resistance upon Deletion of CDR1 in a Clinical Isolate of Candida auris. Antimicrob Agents Chemother 2019 Mar 27;63(4):e00057-19. doi: 10.1128/AAC.00057-19. PMID: 30718246; PMCID: PMC6437491.

Rybak JM, Fortwendel JR, Rogers PD. Emerging threat of triazole-resistant Aspergillus fumigatus. J Antimicrob Chemother 2019 Apr 1;74(4):835-842. doi: 10.1093/jac/dky517. PMID: 30561652; PMCID: PMC6657284.

Rybak JM, Dickens CM, Parker JE, Caudle KE, Manigaba K, Whaley SG, Nishimoto AT, Luna-Tapia A, Roy S, Zhang Q, Barker KS, Palmer GE, Sutter TR, Homayouni R, Wiederhold NP, Kelly SL, Rogers PD. Loss of C-5 Sterol Desaturase Activity Results in Increased Resistance to Azole and Echinocandin Antifungals in a Clinical Isolate of Candida parapsilosis. Antimicrob Agents Chemother 2017 Aug 24;61(9):e00651-17. doi: 10.1128/AAC.00651-17. PMID: 28630186; PMCID: PMC5571332.

Peters BM, Luna-Tapia A, Tournu H, Rybak JM, Rogers PD, Palmer GE. An Azole-Tolerant Endosomal Trafficking Mutant of Candida albicans Is Susceptible to Azole Treatment in a Mouse Model of Vaginal Candidiasis. Antimicrob Agents Chemother 2017 May 24;61(6):e00084-17. doi: 10.1128/AAC.00084-17. PMID: 28348159; PMCID: PMC5444139.

Whaley SG, Berkow EL, Rybak JM, Nishimoto AT, Barker KS, Rogers PD. Azole Antifungal Resistance in Candida albicans and Emerging Non-albicans Candida Species. Front Microbiol 2017 Jan 12;7:2173. doi: 10.3389/fmicb.2016.02173. PMID: 28127295; PMCID: PMC5226953.

Rybak JM, Marx KR, Nishimoto AT, Rogers PD. Isavuconazole: Pharmacology, Pharmacodynamics, and Current Clinical Experience with a New Triazole Antifungal Agent. Pharmacotherapy 2015 Nov;35(11):1037-51. doi: 10.1002/phar.1652. PMID: 26598096.

Last update: April 2025

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