Thomas Duane Dieringer

All Publications

• Enteral feeding tube administration with therapeutic drug monitoring of crushed posaconazole tablets and opened isavuconazonium sulfate capsules. The Journal of antimicrobial chemotherapy Dieringer, T. D., Schaenman, J. M., Davis, M. R. 2022; 77 (5): 1417-1423

  Abstract

  Isavuconazole and posaconazole are commonly used for both prophylaxis and treatment of invasive fungal infections. These agents are formulated for oral administration as a capsule and delayed release (DR) tablet or suspension, respectively. In patients unable to swallow, alternative means of administration, such as crushing posaconazole DR tablets and opening isavuconazole capsules, may be used to avoid IV administration or use of posaconazole suspension, which often produces subtherapeutic concentrations.To assess the feasibility of achieving target plasma drug concentrations with enteral feeding tube (EFT) administration of crushed posaconazole DR tablets and opened isavuconazole capsules.We retrospectively reviewed pharmacy records to identify patients receiving EFT administration of posaconazole or isavuconazole with concurrent therapeutic drug monitoring from October 2019 to June 2021. Plasma concentrations of either agent as well as clinical outcomes were documented.We identified 37 patients receiving 38 courses of EFT isavuconazole or posaconazole. The majority of patients received primary prophylaxis following lung transplantation (64.9%). Plasma concentrations upon first assessment were therapeutic in the majority of patients (posaconazole 71.5%, isavuconazole 83.3%) with a mean level of 1.61 ± 0.77 mg/L for posaconazole and 2.07 ± 1.1 mg/L for isavuconazole. Of those that were subtherapeutic on initial assessment, all but one subsequently achieved target levels upon dose titration. Standard maintenance doses were used in all isavuconazole and most posaconazole patients.Our case series demonstrates that isavuconazole and posaconazole can be administered via EFT with concurrent therapeutic drug monitoring to achieve target plasma concentrations in the majority of patients.

  View details for DOI 10.1093/jac/dkac035

  View details for PubMedID 35174391

• Inpatient antibiotic utilization in the Veterans' Health Administration during the coronavirus disease 2019 (COVID-19) pandemic. Infection control and hospital epidemiology Dieringer, T. D., Furukawa, D., Graber, C. J., Stevens, V. W., Jones, M. M., Rubin, M. A., Goetz, M. B. 2021; 42 (6): 751-753

  Abstract

  Antibiotic prescribing practices across the Veterans' Health Administration (VA) experienced significant shifts during the coronavirus disease 2019 (COVID-19) pandemic. From 2015 to 2019, antibiotic use between January and May decreased from 638 to 602 days of therapy (DOT) per 1,000 days present (DP), while the corresponding months in 2020 saw antibiotic utilization rise to 628 DOT per 1,000 DP.

  View details for DOI 10.1017/ice.2020.1277

  View details for PubMedID 33077000

  View details for PubMedCentralID PMC7653226

• Rizatriptan-Induced Colonic Ischemia: A Case Report and Literature Review. The American journal of gastroenterology Dieringer, T. D., Crossland, D. M., Mahl, T. C. 2018; 113 (1): 148-149

  View details for DOI 10.1038/ajg.2017.422

  View details for PubMedID 29311721

• Essential Staphylococcus aureus toxin export system. Nature medicine Chatterjee, S. S., Joo, H. S., Duong, A. C., Dieringer, T. D., Tan, V. Y., Song, Y., Fischer, E. R., Cheung, G. Y., Li, M., Otto, M. 2013; 19 (3): 364-7

  Abstract

  Widespread antibiotic resistance among important bacterial pathogens such as Staphylococcus aureus calls for alternative routes of drug development. Interfering with crucial virulence determinants is considered a promising new approach to control bacterial infection. Phenol-soluble modulins (PSMs) are peptide toxins with multiple key roles in pathogenesis and have a major impact on the ability of highly virulent S. aureus to cause disease. However, targeting PSMs for therapeutic intervention is hampered by their multitude and diversity. Here we report that an ATP-binding cassette transporter with previously unknown function is responsible for the export of all PSMs, thus representing a single target for complete obstruction of PSM production. The transporter had a strong effect on virulence phenotypes, such as neutrophil lysis, and the extent of its effect on the development of S. aureus infection was similar to that of the sum of all PSMs. Notably, the transporter was essential for bacterial growth. Furthermore, it contributed to producer immunity toward secreted PSMs and defense against PSM-mediated bacterial interference. Our study reveals a noncanonical, dedicated secretion mechanism for an important class of toxins and identifies this mechanism as a comprehensive potential target for the development of drugs to efficiently inhibit the growth and virulence of pathogenic staphylococci.

  View details for DOI 10.1038/nm.3047

  View details for PubMedID 23396209

  View details for PubMedCentralID PMC3594369

• Detection of toxigenic Clostridium difficile in diarrheal stools by rapid real-time polymerase chain reaction. Diagnostic microbiology and infectious disease Goldenberg, S. D., Dieringer, T., French, G. L. 2010; 67 (3): 304-7

  Abstract

  The Cepheid Xpert polymerase chain reaction assay (Sunnyvale, CA) had a sensitivity of 100%, specificity of 96.7%, and positive and negative predictive values of 90.5% and 100%, respectively, compared with toxigenic culture for the laboratory diagnosis of Clostridium difficile in diarrheal stool samples. This test appears to be a significant improvement to poorly performing enzyme immunoassays.

  View details for DOI 10.1016/j.diagmicrobio.2010.02.019

  View details for PubMedID 20542211