About

Dr. Jason Gill joined the Department of Animal Science at Texas A&M University as an Assistant Professor in 2013. He holds a B.S. in Environmental Sciences and an M.S. in Biology from Brock University in Ontario, Canada, and earned his Ph.D. in Food Science from the University of Guelph, Canada, specializing in microbiology. His postdoctoral training was conducted at Texas A&M University in the Department of Biochemistry and Biophysics, where he also served as the inaugural Program Director of the Center for Phage Technology. Dr. Gill's primary research focus is on the biology and application of bacteriophages, viruses that infect bacteria. His work encompasses phage genomics, basic phage biology, and the use of phages in real-world settings, particularly as agents for controlling pathogenic bacteria in humans, animals, and foods. This research is driven by the increasing prevalence of antibiotic resistance and the need to reduce antibiotic use in animal agriculture. Dr. Gill is a member of the Center for Phage Technology and professional societies including the American Society for Microbiology and the International Society for the Viruses of Microbes.

Research topics

• Biology
• Genetics
• Microbiology
• Computer Science
• Artificial Intelligence
• Virology
• Pharmacology
• Database
• Medicine
• Internal medicine
• World Wide Web
• Computational biology
• Intensive care medicine

Selected publications

• Genomic Characterization of 30 Lytic <i>Klebsiella pneumoniae</i> Bacteriophages

  bioRxiv (Cold Spring Harbor Laboratory) · 2026-01-23

  articleOpen accessSenior authorCorresponding

  Abstract The spread and rise of antimicrobial resistance poses a risk to public health due to limited effective treatment options. Alternative antimicrobials that are effective against gram-negative multi-drug resistant pathogens. The increasing rate of carbapenem resistance observed in Klebsiella pneumoniae , indicates the need for alternative antimicrobial options. Bacteriophages that target Klebsiella pneumoniae are promising alternative antimicrobial option, with successful treatments being reported. Here we characterized 30 lytic bacteriophages from various environmental sources and tested their effectiveness against nine clinically relevant carbapenem-resistant K. pneumoniae isolates. These phages were characterized through genomic sequencing, bioinformatic analysis, virulence in liquid medium, and host range on different mediums. Bioinformatic analysis revealed a diverse collection of phages that span 9 ICTV recognized families and 13 genera with genome sizes ranging from 39-349 kbp. The phages were able to inhibit bacterial growth, and no virulence or antibiotic resistance genes were detected within the phage genomes. Host range testing demonstrated phages with broad host range have varying infectivity when plated on different common growth mediums. This study includes candidate phages for further potential development as potential antimicrobial agents against CR-KP, and the complexity in understanding phage-host dynamics of non-capsule phages that target against K. pneumoniae .

  PublisherOA PDFDOI

• Intra-individual diversity of bacteriophage susceptibility in Burkholderia cultured from cystic fibrosis sputum

  Journal of Cystic Fibrosis · 2025-05-31

  article
  PublisherDOI

• Immunogenic <i>Streptococcus equi</i> cell surface proteins identified by ORFeome phage display

  mSphere · 2025-11-25

  articleOpen access

  ABSTRACT Equine strangles caused by Streptococcus equi subspecies equi ( S. equi ) remains a significant cause of morbidity and mortality in horses, and there is a need for improved diagnostic and vaccination strategies for addressing this pathogen. ORFeome phage display is a platform that allows for rapid screening for potential antigenic epitopes by construction of phage-displayed peptide libraries. In this study, an S. equi ORFeome library was used to screen serum from a panel of 17 horses with known exposure to S. equi to identify antigenic bacterial proteins. From this screen, three major S. equi proteins were identified: a novel proline-rich repeat domain protein, a serine peptidase, and the M-like protein SeM. These three proteins are predicted to be expressed on the surface of the bacterial cell by the presence of N- and C-terminal signals. The proline-rich repeat protein and serine peptidase were confirmed to be immunogenic by enzyme-linked immunoassay (ELISA) using the recombinant full-length proteins against sera from horses with strangles, horses infected with the related pathogen S. equi subsp. zooepidemicus , and healthy control horses. Due to the native IgG binding activity of SeM, ELISA against the full-length protein was not conducted, but the specificity of the antibody response against the recovered ORFeome clones was confirmed and an antigenic region identified. Both the proline-rich repeat protein and serine peptidase were found to be highly conserved in global S. equi genomes, indicating these proteins may be useful as vaccine candidates against S. equi or as diagnostic markers to specifically identify S. equi infections in horses. IMPORTANCE This work utilized an ORFeome phage display platform to systematically identify antigenic epitopes produced by Streptococcus equi subspecies equi ( S. equi ), an important equine pathogen and the causative agent of horses strangles. Three major S. equi surface proteins were identified: a novel proline-rich repeat domain protein, a serine peptidase, and the M-like protein SeM. The proline-rich repeat protein and serine peptidase were confirmed to be immunogenic in horses with strangles, and their sequences were shown to be conserved in global S. equi genomes, in contrast to their diversity in S. equi subsp. zooepidemicus. With the well-characterized S. equi immunogenic protein SeM, this paper identified an immunogenic region outside of the reported critical IgG-binding region. This work provides novel insights to the understanding of the S. equi immunogenic proteins and provides peptide regions that could serve as vaccine candidates against S. equi or as diagnostic markers to specifically identify S. equi infections.

  PublisherDOI

• PRISM: A platform for illuminating viral dark matter

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-07-25 · 1 citations

  preprintOpen access

  Abstract The exploration of bacteriophage diversity remains constrained by reliance on conventional plaque assays, which bias discovery toward phages that form visible plaques and propagate efficiently. The discovery process, as well as measuring correct phage concentrations and phage resistance frequencies, are also time-consuming and labor intensive. Here, we present PRISM (Phage Recovery and Investigation in Single-droplet Microenvironments), a droplet microfluidics-based, plating-independent platform for the high-throughput isolation, quantification, and characterization of bacteriophages. By encapsulating phage–host interactions in water-in-oil microdroplets at single-phase resolution, and then coupling them with fluorescence-based detection and sorting at million-droplet scale, PRISM enables rapid identification of novel phages, including those that evade detection in conventional assays. We demonstrate PRISM’s capabilities across several key applications: (i) recovery of both novel “plaquing” and “non-plaquing” Salmonella phages from a concentrated environmental sample, where PRISM recovered multiple representatives of a non-plaquing genus completely missed by conventional plating-based approaches; (ii) accurate titering of poor-plaquing phages such as Rhodococcus phage ReqiDocB7, for which PRISM reported a 2-fold higher titer than conventional plaque assays; and (iii) plating-free determination of phage resistance frequency, with PRISM yielding resistance and lysogeny frequencies (e.g., 1 in 4.4 × 10 5 cells for T7 Escherichia phage resistance and 1 in 21 cells for Escherichia Lambda phage lysogeny) that closely match conventional estimates. These data highlight PRISM’s enhanced resolution and accuracy, as well as its ability to detect rare, non-plaquing, or slow-replicating phages, in a high speed and automated fashion, thereby underscoring the platform’s power to access viral “dark matter” traditionally overlooked using conventional methods.

  PublisherOA PDFDOI

• Bacteriophage treatment is effective against carbapenem-resistant <i>Klebsiella pneumoniae</i> (KPC) in a neutropenic murine model of gastrointestinal translocation and renal infection

  Antimicrobial Agents and Chemotherapy · 2024-12-20 · 4 citations

  articleOpen access

  ABSTRACT Carbapenemase-producing Klebsiella pneumoniae (KPC) are globally emerging pathogens that cause life-threatening infections. Novel treatment alternatives are urgently needed. We therefore investigated the effectiveness of three novel bacteriophages (Spivey, Pharr, and Soft) in a neutropenic murine model of KPC gastrointestinal colonization, translocation, and disseminated infection. Bacteriophage efficacy was determined by residual bacterial burden of KPC (CFU/g) in kidneys. Parallel studies were conducted of bacteriophage pharmacokinetics and resistance. Treatment of mice with 5 × 10 9 PFU of phage cocktail via intraperitoneal injection was effective in significantly reducing renal KPC CFU by 100-fold ( P &lt; 0.01) when administered every 24 h and 1000-fold ( P &lt; 0.01) every 12 h. Moreover, a combination of bacteriophage and ceftazidime-avibactam produced a synergistic effect, resulting in a 10 5 -fold reduction in bacterial burden in cecum and kidney ( P &lt; 0.001 in both tissues). Prophylactic administration of bacteriophages via oral gavage did not prevent KPC translocation to the kidneys. Bacteriophage decay determined by linear regression of the ln of mean concentrations demonstrated R 2 values in plasma of 0.941, kidney 0.976, and cecum 0.918, with half-lives of t 1/2 = 2.5 h. Furthermore, a phage-resistant mutant displayed increased sensitivity to serum killing in vitro , but did not show significant defects in renal infection in vivo . A combination of bacteriophages demonstrated significant efficacy alone and synergy with ceftazidime/avibactam in the treatment of experimental disseminated KPC infection in neutropenic mice.

  PublisherDOI

• :<i>The Good Virus: The Amazing Story and Forgotten Promise of the Phage</i>

  The Quarterly Review of Biology · 2024-11-15

  review1st authorCorresponding
  PublisherDOI

• Bacteriophage Treatment against Carbapenem-resistant <i>Klebsiella pneumoniae</i> (KPC) in a Neutropenic Murine Model of Gastrointestinal Translocation and Renal infection

  bioRxiv (Cold Spring Harbor Laboratory) · 2024-06-22 · 2 citations

  preprintOpen access

  ABSTRACT Background Carbapenemase producing Klebsiella pneumoniae (KPC) are globally emerging pathogens which that cause life-threatening infections. Novel treatment alternatives are urgently needed. Methods We therefore investigated the effectiveness of three novel bacteriophages (Spivey, Pharr and Soft) in a neutropenic murine model of KPC gastrointestinal colonization, translocation, and disseminated infection. Bacteriophage efficacy was determined by residual bacterial burden of KPC in kidneys. Parallel studies were conducted of bacteriophage pharmacokinetics and resistance.. Results Treatment of mice with 5×10 9 PFU of phage cocktail via intraperitoneal injection was effective in significantly reducing renal KPC burden by 10 2 CFU (p&lt;0.01) when administered every 24 hours and 10 3 CFU (p&lt;0.01) every 12 hours. Moreover, a combination of bacteriophage and ceftazidime-avibactam produced a synergistic effect, resulting in a 10 5 reduction in bacterial burden in caecum and kidney (p&lt;0.001 in both tissues). Prophylactic administration of bacteriophages via oral gavage did not prevent KPC translocation to the kidneys. Bacteriophage decay determined by linear regression of the ln of mean concentrations demonstrated R 2 values in plasma of 0.941, kidney 0.976, and caecum 0.918, with half-lives of 2.5h &lt; t 1/2 &lt; 3.5 h. Furthermore, a phage-resistant mutant displayed increased sensitivity to serum killing in vitro , but did not show significant defects in renal infection in vivo . Conclusions A combination of bacteriophages demonstrated significant efficacy alone and synergy with ceftazidime/avibactam in treatment of experimental disseminated KPC infection in neutropenic mice.

  PublisherOA PDFDOI

• Therapeutic Potential of Intravenous Phage as Standalone Therapy for Recurrent Drug-Resistant Urinary Tract Infections

  Antimicrobial Agents and Chemotherapy · 2023 · 60 citations

  • Medicine
  • Intensive care medicine
  • Internal medicine

  Recurrent urinary tract infections (rUTI) are common in kidney transplant recipients (KTR) and are associated with multidrug resistance and increased morbidity/mortality. Novel antibiotic alternatives to reduce UTI recurrence are critically needed. We describe a case of rUTI due to extended spectrum beta lactamase (ESBL) Klebsiella pneumoniae in a KTR that was treated successfully with 4 weeks of adjunctive intravenous bacteriophage therapy alone, without concomitant antibiotics, and with no recurrence in a year of follow-up.

  PublisherOA PDFDOI

• Phage Milagro: a platform for engineering a broad host range virulent phage for <i>Burkholderia</i>

  Journal of Virology · 2023-11-09 · 15 citations

  articleOpen accessSenior author

  ABSTRACT The Burkholderia cepacia complex (Bcc) causes life-threatening respiratory tract infections in persons with cystic fibrosis (CF). In CF patients, end-stage pulmonary disease often requires lung transplantation, and pre-transplant colonization with antibiotic-resistant Burkholderia is predictive of poor post-transplant outcomes. To address this issue, phage therapy has been proposed as a treatment for these infections. However, the majority of characterized Bcc phages are temperate and are therefore difficult to use as therapeutics, and the few obligately lytic phages that have been isolated have limited host ranges. To overcome these limitations, we have produced a virulent, broad-host range derivative of the temperate Burkholderia cenocepacia phage Milagro. Phage Milagro is a 39.1-kb temperate myophage related to phage KL3 and the paradigm coliphage P2. This phage showed a phenotype of spontaneous autoplaquing on lawns of Milagro lysogens, and these autoplaques were found to be produced by virulent mutants of the parental phage Milagro. Mutations associated with virulence were identified as single base changes, insertions or deletions in the phage lysogeny control region that define potential operator sites required for lysogen maintenance. To improve phage host range, the C-terminal domain of the Milagro tail fiber was replaced with the receptor-binding domain of the broad-host range tailocin (high molecular weight bacteriocin) BceTMilo. A spontaneous virulent mutant of this engineered phage, designated Milagro vir gp20:Milo , exhibited an expanded host range over the parental phage and is able to infect multiple Bcc species including B. cenocepacia , Burkholderia multivorans , Burkholderia gladioli, Burkholderia dolosa , and Burkholderia vietnamensis . IMPORTANCE Burkholderia infections are a significant concern in people with CF and other immunocompromising disorders, and are difficult to treat with conventional antibiotics due to their inherent drug resistance. Bacteriophages, or bacterial viruses, are now seen as a potential alternative therapy for these infections, but most of the naturally occurring phages are temperate and have narrow host ranges, which limit their utility as therapeutics. Here we describe the temperate Burkholderia phage Milagro and our efforts to engineer this phage into a potential therapeutic by expanding the phage host range and selecting for phage mutants that are strictly virulent. This approach may be used to generate new therapeutic agents for treating intractable infections in CF patients.

  PublisherOA PDFDOI

• A Longitudinal Study on the Dynamics of Salmonella enterica Prevalence and Serovar Composition in Beef Cattle Feces and Lymph Nodes and Potential Contributing Sources from the Feedlot Environment

  Applied and Environmental Microbiology · 2023-04-06 · 16 citations

  articleOpen access

  Salmonella contamination of beef products, specifically from the incorporation of bovine lymph nodes into ground beef, remains a food safety concern. Current postharvest Salmonella mitigation techniques do not address Salmonella bacteria that are harbored in the lymph nodes, nor is it well understood how Salmonella invades the lymph nodes. Alternatively, preharvest mitigation techniques that can be applied to the feedlot environment, such as moisture applications, probiotics, or bacteriophage, may reduce Salmonella before dissemination into cattle lymph nodes. However, previous research conducted in cattle feedlots includes study designs that are cross-sectional, are limited to point-in-time sampling, or are limited to sampling of the cattle host, making it difficult to assess the Salmonella interactions between environment and hosts. This longitudinal analysis of the cattle feedlot explores the Salmonella dynamics between the feedlot environment and beef cattle over time to determine the applicability of preharvest environmental treatments.

  PublisherDOI

Recent grants

• Development of therapeutic bacteriophages against carbapenemase-resistant Klebsiella pneumoniae

  NIH · $470k · 2015–2017

• Development of therapeutic bacteriophages against carbapenemase-resistant Klebsiella pneumoniae

  NIH · $1.4M · 2015–2021

Frequent coauthors

• Mei Liu

  Chinese Academy of Medical Sciences & Peking Union Medical College

  67 shared

• Lauren Lessor

  Texas A&M University

  24 shared

• Chandler O’Leary

  Texas A&M University

  22 shared

• Ry Young

  Texas A&M University

  21 shared

• Jolene Ramsey

  Texas A&M University

  21 shared

• Heather Newkirk

  Texas A&M University

  19 shared

• Tram Le

  Texas A&M University

  14 shared

• Yicheng Xie

  Children's Hospital of Zhejiang University

  13 shared

Education

• B.S., Environmental Sciences

  Brock University

• M.S., Biology

  Brock University

• Ph.D., Food Science

  University of Guelph