About

Robert (Rob) Striker is an Associate Professor of Medicine and Medical Microbiology & Immunology at the University of Wisconsin–Madison. His educational background includes a degree from Purdue University in 1988, an M.D. from Washington University in St. Louis in 1995, and a Ph.D. also from Washington University in 1995, where his research focused on the assembly and specificity of P pili. He completed an Internal Medicine Residency at CPMC in San Francisco and a Post-Doctoral Fellowship in Infectious Diseases at Stanford University, supported by a Howard Hughes Fellowship. His research group aims to improve therapy for human infectious diseases by developing new antimicrobials and optimizing their use through better stewardship and application. His work focuses on two main areas: the laboratory-based development of inhibitors targeting pathogen-specific phosphorylation events, particularly bacterial kinases such as PASTA kinases in MRSA and other organisms, and the individualization of therapy for human viral infections, including hepatitis C and HIV. His research involves molecular biology, biochemistry, and mass spectrometry to identify critical phosphorylation events and develop targeted treatments. He collaborates with various institutions and resources, including the VA Million Veteran Program, to link clinical data with human genetics and tailor therapeutic approaches accordingly.

Research topics

• Medicine
• Biology
• Internal medicine
• Genetics
• Environmental health
• Clinical psychology
• Demography
• Psychiatry
• Psychology
• Bioinformatics
• Cardiology
• Surgery
• Endocrinology
• Medical emergency
• Pediatrics

Selected publications

• Piercing Through: Lefamulin Treatment of an Antibiotic-Resistant Mycoplasma Genitalium Urethritis

  Venereology · 2025-06-26 · 1 citations

  articleOpen accessSenior authorCorresponding

  Multidrug-resistant (MDR) Mycoplasma genitalium (M. genitalium) presents a significant risk of treatment failure in many sexually transmitted infections (STIs) and can result in persistent and recurrent urethritis or cervicitis. This case report describes a recurrent M. genitalium urethritis resistant to sulfamethoxazole-trimethoprim (TMP-SMX), doxycycline, and moxifloxacin. The infection was ultimately cured after both the removal of a nidus of infection and through the use of Lefamulin. Lefamulin is a novel agent approved for use in community-acquired bacterial pneumonia and bacterial skin infections that may be useful in difficult sexually transmitted infections. Background/Objectives: Deciding whether or not to treat M. genitalium can be challenging as it can be a colonizer, or present with a symptomatic pathogen, and even if it is causing symptoms, it can be drug-resistant. Our objective here is to highlight important considerations on whether or not to treat and, if so, what options exist. Conclusions: In a world of increasing drug-resistant STIs, this case highlights the challenges of managing MDR M. genitalium and how foreign bodies can allow reoccurrence. Also highlighted in this case, Lefamulin appears to be a viable alternative line of treatment of MDR M. genitalium that defies other first-line antibiotics.

  PublisherOA PDFDOI

• Challenges and Opportunities in Cancer Screening in Incarcerated Populations

  Journal of the American College of Radiology · 2025-04-19

  articleOpen access
  PublisherOA PDFDOI

• Interpretation of HIV Serologies in the Era of PrEP: Two Cases of False Positives.

  PubMed · 2025-01-01

  article

  INTRODUCTION: More availability of HIV pre-exposure prophylaxis (PrEP) is needed to end the HIV epidemic, but this means more clinicians will encounter false positive HIV test results. These cases highlight such occurrences and the steps a clinician may take to determine the significance of such results. CASE PRESENTATION: We present the case of a 68-year-old male who presented for routine follow-up for HIV PrEP and a 41-year-old transgender male who presented to establish care with a primary care clinician. On labs, both had repeatedly positive HIV antigen/antibody tests with undetectable viral loads. DISCUSSION: With increasing prescription of HIV PrEP comes a need for accurate interpretation of HIV serologies. HIV PrEP users may have altered stages of seroconversion. Additionally, heterophile antibody interference can lead to false positive or negative results. CONCLUSIONS: The reader should gain an understanding of HIV testing, potential pitfalls, and next steps amidst unclear results.

  Publisher

• Single-cell delineation of strain-specific HIV-1 Vif activities using dual reporter sensor cells and live cell imaging

  Journal of Virology · 2025-02-25

  articleOpen access

  ABSTRACT Human immunodeficiency virus type 1 (HIV-1) genome diversification is a key determinant of viral evolution and the pathogenesis of HIV/AIDS. Antiretroviral therapy is non-curative, and in the context of monitoring the latent reservoir, precision tools are needed to detect and enumerate HIV-1 genomes as well as to assess their heterogeneity, replication potential, and predict responses to therapy. Current sequencing-based methodologies are often unable to confirm intact genomes and most cell-based reporters provide limited information pertaining to viral fitness. In this study, we describe dual reporter sensor cells (DRSCs), an imaging-based reporter system designed to detect HIV-1 infection and measure several independent attributes of the virus in a single-cell high-content assay. We show that the DRSC assay can be used to measure infection, viral gene activation kinetics, and quantify viral circumvention of host antiviral responses. Using the DRSCs, we confirmed markedly different functional heterogeneity for vif alleles derived from diverse HIV-1 strains and subtypes affecting both rates of APOBEC3G degradation and the cell cycle. Furthermore, the assay allowed for the delineation of virus co-receptor preference (X4- vs R5-tropism) and visualization of virion assembly. Overall, our study illustrates proof-of-principle for a multivariate imaging-based cell-based system capable of detecting HIV-1 and studying viral genetic variability with greater data richness relative to prior available modalities. IMPORTANCE Human immunodeficiency virus type 1 (HIV-1) is highly heterogeneous and constantly mutating. These changes drive immune evasion and can cause treatment efforts to fail. Here, we describe the “dual reporter sensor cell” (DRSC) assay; a novel imaging-based approach that allows for the detection of HIV-1 infection coupled with a multivariate definition of several independent phenotypic aspects of viral genome activity in a single integrated assay. We validate the DRSC system by studying lab-adapted and patient isolate-derived versions of the viral Vif accessory protein, confirming marked differences in the capacity of diverse vif alleles to mediate downregulation of antiviral APOBEC3G proteins and dysregulate the cell cycle.

  PublisherDOI

• National Analysis of More Than 48,000 Veterans With HIV Demonstrates CD4/CD8 Ratio as a Risk Marker for Anal Intraepithelial Lesions and Anal Cancer

  Diseases of the Colon & Rectum · 2025-01-02 · 1 citations

  article

  BACKGROUND: Anal squamous intraepithelial lesions are identifiable and treatable precancerous lesions that lack defined risk factors determining screening necessity. OBJECTIVE: Assess the prevalence and risk factors associated with low- and high-grade anal squamous intraepithelial lesions and anal squamous-cell carcinoma. DESIGN: Retrospective cohort analysis of veterans with HIV between 1999 and 2023. SETTINGS: National multicenter study of the Department of Veterans Affairs. PATIENTS: Veterans with HIV who had >1 year of follow-up and no anal squamous intraepithelial lesions or anal cancer diagnosis before the study period. MAIN OUTCOME MEASURES: Primary outcomes include the prevalence, disease-free survival rates, and HRs associated with risk factors for developing anal squamous intraepithelial lesions and/or anal cancer. RESULTS: A total of 48,368 patients were analyzed. The mean age of patients at study initiation was 47.8 years, with a mean follow-up of 12.3 years. Seven thousand five hundred seventy-two patients (16%) had at least 1 anal cytopathology or histopathology result. The prevalence of anal disease was recorded for low-grade disease (n = 1513; 3.1%), high-grade disease (n = 1484; 3.1%), and cancer (n = 664; 1.4%). Mean (SD) times to first incident low-grade disease, high-grade disease, and cancer were 8.5 (6.0), 9.1 (6.0), and 9.7 (6.2) years, respectively. Five-year, 10-year, and 20-year disease-free survival rates for the development of low-grade disease, high-grade disease, or cancer were 97.5%, 94.5%, and 88.4%, respectively. Cox regression modeling demonstrated that CD4/CD8 ratios of <0.5 were associated with an increased risk of anal cancer (HR, 3.93; 95% CI, 3.33-4.63; p < 0.001). LIMITATIONS: Retrospective study that focused almost exclusively on male US veterans. Results might not apply to non-male, non-US populations. CONCLUSIONS: National analysis of more than 48,000 veterans with HIV demonstrates that 16% had anal cytopathology or histopathology results with an anal cancer prevalence of 1.4%. CD4/CD8 ratios of <0.5 correlate strongly with the severity of anal disease and can help identify patients at the highest risk for anal cancer to prioritize screening efforts. See Video Abstract. ANLISIS NACIONAL DE MS DE VETERANOS CON VIH DEMUESTRA QUE LA RELACIN CD/CD ES UN MARCADOR DE RIESGO DE LESIONES INTRAEPITELIALES ANALES Y CNCER ANAL: ANTECEDENTES:Las lesiones intraepiteliales escamosas anales son lesiones precancerosas identificables y tratables que carecen de factores de riesgo definidos que determinen la necesidad de detección.OBJETIVO:Evaluar la prevalencia y los factores de riesgo asociados con las lesiones intraepiteliales escamosas anales de grado bajo y alto y el carcinoma de células escamosas anal.DISEÑO:Análisis de cohorte retrospectivo de veteranos con VIH entre 1999 y 2023.ESTABLECIMIENTO:Estudio multicéntrico nacional del Departamento de Asuntos de Veteranos.PACIENTES:Veteranos con VIH que tuvieron >1 año de seguimiento y sin lesiones intraepiteliales escamosas anales ni diagnóstico de cáncer anal antes del período de estudio.PRINCIPALES RESULTADOS Y MEDIDAS:Los resultados primarios incluyen la prevalencia, las tasas de supervivencia libre de enfermedad y los cocientes de riesgo asociados con los factores de riesgo para desarrollar lesiones intraepiteliales escamosas anales y/o cáncer anal.RESULTADOS:Se analizaron 48.368 pacientes. La edad promedio de los pacientes al inicio del estudio fue de 47,8 años con un seguimiento medio de 12,3 años. 7.572 (16%) pacientes tuvieron al menos un resultado de citopatología o histopatología anal. Se registró la prevalencia de enfermedad anal para enfermedad de bajo grado (n = 1.513, 3,1%), enfermedad de alto grado (n = 1.484, 3,1%) y cáncer (n = 664, 1,4%). Los tiempos medios hasta el primer incidente de enfermedad de bajo grado, enfermedad de alto grado y cáncer fueron 8,5 (DE = 6,0), 9,1 (DE = 6,0) y 9,7 (DE = 6,2) años, respectivamente. Las tasas de supervivencia libre de enfermedad a 5 años, 10 años y 20 años para el desarrollo de enfermedad de bajo grado, enfermedad de alto grado o cáncer fueron 97,5%, 94,5% y 88,4%, respectivamente. El modelo de regresión de Cox demostró que los índices CD4/CD8 <0,5 se asociaban con un mayor riesgo de cáncer anal (HR: 3,93, IC del 95 %: 3,33-4,63, p < 0,001).LIMITACIONES:Estudio retrospectivo que se centra casi exclusivamente en veteranos estadounidenses de sexo masculino. Los resultados podrían no aplicarse a poblaciones no masculinas ni estadounidenses.CONCLUSIONES:El análisis nacional de más de 48 000 veteranos con VIH demuestra que el 16 % tenía resultados de citopatología o histopatología anal con una prevalencia de cáncer anal del 1,4 %. Los índices CD4/CD8 <0,5 se correlacionan fuertemente con la gravedad de la enfermedad anal y pueden ayudar a identificar a los pacientes con mayor riesgo de cáncer anal para priorizar los esfuerzos de detección. (Traducción-Dr Yolanda Colorado ).

  PublisherDOI

• Fatal toxoplasmic encephalitis triggered by anti-TNF therapy

  Heliyon · 2025-01-21 · 1 citations

  articleOpen accessSenior author

  seropositivity testing be considered before and after initiation of anti-TNF-α therapy as is done for other infections such as tuberculosis.

  PublisherDOI

• Viruses tipping the scales: The role of the CD4/CD8 ratio in determining viral outcome

  Virology · 2024-11-28 · 1 citations

  reviewSenior authorCorresponding
  PublisherDOI

• Monitoring immune recovery on HIV therapy: critical, helpful, or waste of money in the current era?

  AIDS · 2024-02-01 · 4 citations

  editorialOpen accessSenior authorCorresponding

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• Using T-Cell Subsets to Better Characterize Immunoresiliency and Immunodeficiency in Patients with Recurrent Infections

  Infectious Disease Reports · 2024-12-16

  articleOpen accessSenior authorCorresponding

  BACKGROUND/OBJECTIVES: Common Variable Immunodeficiency Disease (CVID) and other immunodeficiencies can present in subtle and variable ways. Whether or not a genetic lesion can be identified, there are not well understood biomarkers that quantitatively describe how severe a deficiency is. Here we discuss two possible ranking systems, CD4/CD8 T cell ratios and Immune Health Grades, and how such data maybe applicable to some immunodeficiencies. METHODS: This is not a systematic review, but we identify papers relating to immunodeficiencies with enough data to comment on the CD4/CD8 and Immune Health Grade. We also summarized relevant data publicly available from USIDNET, a website that compiles data on immunodeficiencies, and provide two new cases that illustrate ways that this information can alter clinical assessment. RESULTS: We review the HIV literature on CD4/CD8 T cell data and how this correlates with both immunologic function and comorbidity better than CD4 count alone. The ratio aslso relates to a new system called Immune Health Grades (IHG) derived from young adult to elderly subjects from many NIH cohorts without HIV. CVID is often thought of as an antibody problem, but in fact most patients also have low CD4/CD8 ratio and other cellular abnormalities. We review IDNET to categorize nine molecular immunodeficiencies including two subcategories of CVID into low, normal, or high ratios. Finally, we present two new cases in the literature of patients with recurrent infection and discuss how viewing the cases through the "lens" of CD4/CD8 ratio and IHG can facilitate clinical decisions. CONCLUSIONS: Emerging data suggests at least some immunodeficiencies can be grouped by how abnormal their CD4/CD8 ratio or IHG. This represents a clinically available biomarker that can be tracked to see if the condition is worsening or not.

  PublisherOA PDFDOI

• Analysis of &gt;15 000 Solid Organ Transplant Recipients Reveals Nonanal Genitourinary HPV-related Disease as Highest Risk Predictor for Anal Squamous Intraepithelial Lesions/Anal Cancer

  Transplantation · 2024-02-22 · 1 citations

  articleOpen access

  BACKGROUND: Solid organ transplantation is a risk predictor for virally-mediated anal squamous intraepithelial lesions and cancer (anal disease). Precancerous squamous intraepithelial lesions can be detected by screening, and treatment may prevent cancer progression. Screening recommendations are not well defined. We aim to define prevalence and describe risk predictors for anal disease in a large population of solid organ transplant recipients. METHODS: Retrospective single-center cohort analysis included solid organ transplant recipients cared for between 2001 and 2022 (N = 15 362). The cohort of recipients who developed anal disease was compared with those who did not. Greedy propensity score matching was performed for organ-specific recipients, and time-to-event analysis for the development of anal disease was performed in those with genitourinary human papilloma virus (HPV) disease versus those without. RESULTS: Prevalence of anal disease was 0.6% (cancer 0.2%). The average years from transplant to the diagnosis of anal disease was 11.67. Anal disease was more common in women (68.5% versus 31.5%, P < 0.001), patients who had other HPV-related genitourinary diseases (40.4% versus 0.6%, P < 0.001), who were of younger age at transplant (39.62 versus 46.58, P < 0.001), and had increased years from transplant (17.06 versus 12.57, P < 0.001). In multivariate analysis, the odds of anal disease increased by 4% each year posttransplant. History of genitourinary HPV disease (odds ratio 69.63) and female sex (odds ratio 1.96) were the most significant risk predictors for anal disease. CONCLUSIONS: The prevalence of anal cancer among solid organ transplant recipients was equal to the general population (0.2%). Due to the low prevalence of overall disease, these data suggest that anal screenings in transplant recipients should be targeted to higher-risk subsets: female recipients farther out from transplant and patients with genitourinary HPV-related diseases.

  PublisherOA PDFDOI

Recent grants

• NIH Grant K08AI055750

  NIH · $388k · 2007

• NIH Grant I01CX000117

  NIH · 2012

• Novel selective substituted aminofurazans kinase inhibitors for Drug resistant Bacteria

  NIH · 2018–2021

Frequent coauthors

• Kelly Cho

  VA Boston Healthcare System

  43 shared

• Philip S. Tsao

  VA Palo Alto Health Care System

  41 shared

• Christopher J. O’Donnell

  VA Boston Healthcare System

  37 shared

• Peter W.F. Wilson

  Emory Clinic

  28 shared

• Kyong–Mi Chang

  University of Pennsylvania

  25 shared

• Jean C. Beckham

  Durham VA Health Care System

  25 shared

• Thomas G. Schulze

  National Institute of Mental Health

  24 shared

• Saiju Pyarajan

  VA Boston Healthcare System

  24 shared

Education

• B.S.

  Purdue University

  1988

• M.D.

  Washington U.

  1995

• Ph.D., Assembly and Specificity of P pili

  Wash U.

  1995

• Other, Infectious Diseases Post-Doctoral Fellow

  Stanford University

• Other, Howard Hughes Postdoctoral Fellow

  Stanford University