Pathogenic Microbiology Commons^™

Validation Of A Real-Time Pcr Laboratory Developed Test For The Detection Of Pneumocystis Jirovecii In Bronchoalveolar Lavage Samples, Caitlyn Moon

Honors Scholar Theses

Pneumocystis jirovecii is an opportunistic, host-obligate fungal pathogen responsible for causing P. jirovecii pneumonia (PJP) in humans. PJP is treated with trimethoprim-sulfamethoxazole (TMP-SMX), a strong broad-spectrum antibiotic that carries risk of renal and hepatotoxicity. Therefore, rapid diagnosis or exclusion of PJP is crucial to ensure PJP-positive patients receive effective treatment and PJP-negative patients avoid unnecessary antibiotics. Unlike most microorganisms, P. jirovecii cannot be cultured, presenting complications for the typical methods of diagnosing fungal pathogens. Historically, the gold standard for diagnosis was direct microscopic examination with stains such as methenamine silver and calcofluor white, but this diagnostic technique requires highly skilled …

Exploring Biopsychosocial Influences On Hookup Culture And Disrupting Compulsory Behaviors In Emerging Adults: A Multidisciplinary Analysis Of A Contemporary Public Health Concern, Catherine Benjamin

Honors Theses and Capstones

Multidisciplinary analysis, including biology, psychology, and sociology, to better understand the compulsory Hookup Culture that exists as a contemporary public health concern among the age group defined as emerging adults. Sexually Transmitted Infections (STIs) diagnoses are steadily rising in the United States and disproportionately affecting college students. Early socialization and current educational resources that contribute to shame and stigma are discussed to explain how lifestyle and social conditions can act as risk factors for individual health outcomes.

Synergistic Cefiderocol-Containing Antibiotic Combinations Active Against Highly Drug-Resistant Acinetobacter Baumannii Patient Isolates With Diverse Resistance Mechanisms, Justin Halim, Andrew P. Keane, Jeannete Bouzo, Tope Aderibigbe, Jessica A. Chicola, Katie T. Nolan, Keertana Jonnalagadda, Jason X. Tran, Valerie J. Carabetta

Rowan-Virtua School of Osteopathic Medicine Departmental Research

BACKGROUND: Acinetobacter baumannii is a nosocomial pathogen known for rapidly developing resistance to nearly all antibiotics, including last-line agents. Cefiderocol, a novel siderophore cephalosporin, has shown in vitro activity against A. baumannii and is now used clinically, but resistance is emerging. Data on cefiderocol-based antibiotic combinations are limited.

OBJECTIVES: To evaluate the in vitro activity of cefiderocol alone and in combination with other antibiotics against XDR and PDR A. baumannii clinical isolates, and to explore resistance mechanisms underlying cefiderocol synergy.

METHODS: We tested 21 XDR/PDR clinical isolates and one NDM-1-producing strain using broth microdilution and checkerboard assays with cefiderocol and …

Multisociety Guidance For Infection Prevention And Control In Nursing Homes, Lona Mody, Sonali D. Advani, Muhammad Salman Ashraf, Allison H. Bartlett, Suzanne F. Bradley, Deborah P. Burdsall, Jennifer A. Hanrahan, Susan S. Huang, Robert L.P. Jump, Lindsay Nicolle, Mary-Claire Roghmann, Patricia Stone, Rekha K. Murthy

Department of Medicine Faculty Publications

This multisociety guidance was endorsed by SHEA, APIC, IDSA, PALTmed, and AGS. It provides recommendations for infection prevention and control (IPC) in the context of the complexity of nursing home care in the United States: increased medical acuity of residents, the spread of multidrug-resistant organisms, and the threat of emerging pathogens. Recommendations and implementation suggestions address IPC leadership, staffing, and resources, healthcare personnel and residents‘ adherence to precautions and effective hand hygiene, outbreak preparedness, training, occupational health, cleaning and disinfection in the care environment, and the involvement of IPC in the facility. The guidance also addresses the challenges of maintaining …

Development Of A Proposed Selective Medium For The Isolation And Differentiation Of P. Sordellii, Dimyana Bottros

Honors Undergraduate Theses

Clostridium, a genus of anaerobic, spore-forming bacteria, includes clinically and ecologically significant species like Clostridium difficile and Paeniclostridium sordellii. C. difficile causes antibiotic-associated colitis, while P. sordellii is linked to fatal infections and spontaneous abortions. Recent studies found both species in marine sediments, suggesting their role in environmental and wildlife health disturbances, including the 2013 mass mortality of over 300 manatees in the Indian River Lagoon. However, isolating and differentiating P. sordellii is challenging due to the lack of selective media optimized for its growth. This thesis proposes a novel selective medium tailored to P. sordellii’s physiological …

Oral Microbiome And Inflammatory Bowel Disease: New Understanding And Call To Action, Michael Saadeh, Sydney Donohue, Shaina Ailawadi, Gordon Hong, David A. Johnson

Department of Medicine Faculty Publications

The oral microbiome is the second largest microbial community in the human body after the gut microbiome. It includes an array of fungi, bacteria, amoebae, flagellates, archaea, and viruses, all of which are potential pathogens. This microbiome can act as a facilitator not only for protection but also for aggravation when dysbiosis occurs. Although conventional thought is this is primarily in terms of oral health issues, such as dental caries and gingival disease. The systemic effects of the oral microbiome however, are relevant to both gastrointestinal (GI) disease and non-GI disease. These systemic risks occur for several reasons, including upregulation …

Invasion Of Superbugs: Cockroach-Driven Outbreak Of Multidrug-Resistant Enterobacter In An Icu, Jennifer Hanrahan, Nicholas Schouten, Steven H. Fyffe, Annette Jencson, Stephanie Stroever

Department of Medicine Faculty Publications

Objective: To describe factors in an outbreak of multidrug-resistant Enterobacter cloacae (MRE) in an intensive care unit (ICU) over a 20-month period including the likely contribution of cockroaches to the outbreak.

Design: This is a retrospective descriptive study.

Setting: ICU in an urban hospital.

Patients: All patients admitted to the ICU during the 20-month outbreak period were included in the study.

Interventions: Infection prevention interventions included contact isolation, hand hygiene, dedicated patient equipment, environmental cultures, and pest control.

Results: 25 patients were identified as being colonized or infected with MRE. Relatedness of the outbreak strain and strains found in cockroaches …

Elucidating The Impact Of Sos-Response Timing In On Escherichia Coli Survival Following Treatment With Fluoroquinolone Topoisomerase Inhibitors, Stephanie Schofield

Honors Scholar Theses

Antibiotic treatment failure is a public health crisis, with a 2019 report stating that roughly 35,000 deaths occur in the United States yearly due to bacterial infections that are unresponsive to antibiotics (1). One complication in the treatment of bacterial infection is antibiotic persistence which further compromises our battle to effectively treat infection. Bacterial persisters can exist in clonal bacterial cultures and can tolerate antibiotic treatment by undergoing reversible phenotypic changes. They can survive drug concentrations that their genetically identical kin cannot. Some persisters remain in a slow growing state and are difficult to target with current antibiotics. A specific …

A Systematic Review: Toxoplasma Gondii Infection And Drugs Of Abuse, Amani Sastry

Annual Research Symposium

No abstract provided.

Clonal Diversity, Antibiotic Resistance, And Virulence Factor Prevalence Of Community Associated Staphylococcus Aureus In Southeastern Virginia, Katelyn D. Cranmer, Mohan D. Pant, Suzanne Quesnel, Julia A. Sharp

EVMS School of Health Professions Faculty Publications

Staphylococcus aureus is a significant human pathogen with a formidable propensity for antibiotic resistance. Worldwide, it is the leading cause of skin and soft tissue infections (SSTI), septic arthritis, osteomyelitis, and infective endocarditis originating from both community- and healthcare associated settings. Although often grouped by methicillin resistance, both methicillin-resistant (MRSA) and methicillin-sensitive (MSSA) strains are known to cause significant pathologies and injuries. Virulence factors and growing resistance to antibiotics play major roles in the pathogenicity of community-associated strains. In our study, we examined the genetic variability and acquired antibiograms of 122 S. aureus clinical isolates from SSTI, blood, and urinary …

Alternative Precautionary Measures Yielding Lower C. Diff Infection Rates In Healthcare Facilities, Matthew Kramer

Symposium of Student Scholars

Background: An international healthcare concern is the persistent spread of Clostridium difficile, a Gram-positive spore forming bacterium that is responsible for the most common hospital-acquired infection, amongst patients.

Objective: A systematic review was performed to summarize evidence that the interventions utilized in healthcare facilities which indicate a patient’s precautionary status are insufficient, outdated, and commonly lead to infection in neighboring patient rooms. Databases such as PubMed, NCBI, Google Scholar, and APHA’s Medical Care were searched, covering the period from 2017-2022. Studies were included if their focus concentrated on C. diff and the precautionary measures taken by employees at healthcare …

Biowill - Characterising Willow Bark Bio-Actives For Skin Therapies, Arnold Marisa

ORBioM (Open Research BioSciences Meeting)

Willow bark is considered as a disposable by-product when processing willow for biomass. Willow (Salix) is known to contain high value bioactive compounds which include salicin and its derivatives, and other phytochemicals of interest such as polyphenols and flavonoids. The plant is historically known as the primary source of salicylates to which the well-known drug aspirin is derived from. The work forms part of the Interreg project BioWILL, which is focused on integrated “Zero Waste” biorefinery utilising all fractions of willow feedstock for the production of biochemicals and renewable energy. This project aims to investigate the crude and …

Higher Entropy Observed In Sars-Cov-2 Genomes From The First Covid-19 Wave In Pakistan, Najia Karim Ghanchi, Asghar Nasir, Kiran I. Masood, Syed Hani Abidi, Syed Faisal Mahmood, Akber Kanji, Safina Abdul Razzak, Waqasuddin Khan, Saba Shahid, Maliha Yameen, Ali Raza, Javaria Ashraf, Zeeshan Ansar Ahmed, Mohammad Buksh Dharejo, Nazneen Islam, Zahra Hasan, Rumina Hasan

Department of Pathology and Laboratory Medicine

Background: We investigated the genome diversity of SARS-CoV-2 associated with the early COVID-19 period to investigate evolution of the virus in Pakistan.
Materials and methods: We studied ninety SARS-CoV-2 strains isolated between March and October 2020. Whole genome sequences from our laboratory and available genomes were used to investigate phylogeny, genetic variantion and mutation rates of SARS-CoV-2 strains in Pakistan. Site specific entropy analysis compared mutation rates between strains isolated before and after June 2020.
Results: In March, strains belonging to L, S, V and GH clades were observed but by October, only L and GH strains were present. The …

Host Cell Responses To Zika Virus Infection, Bikash Ranjan Sahoo

School of Veterinary and Biomedical Sciences: Dissertations, Theses, and Student Research

The re-emergence of Zika virus (ZIKV) in 2015 as a significant human pathogen causing neurological diseases in infants as well as adults is a serious global health concern. A clear understanding of the mechanisms involved in ZIKV replication in infected host cells as well as the host responses to virus infection are keys to the development of therapeutic strategies against ZIKV. Studies conducted in this dissertation demonstrate that ZIKV infection induces the activation of mTOR signaling cascade that promotes viral protein accumulation and infectious progeny production. While both mTORC1 and mTORC2 are essential for ZIKV replication, the observation that depletion …

Development Of Vaccines And Antivirals Against Zika Virus, Aryamav Pattnaik

School of Veterinary and Biomedical Sciences: Dissertations, Theses, and Student Research

The re-emergence of Zika virus (ZIKV), an arbovirus, poses a major global human health concern because of its ability to cause congenital abnormalities and neurological diseases. While many candidate vaccines and antiviral drugs are in the developmental pipeline, none have been approved for use against ZIKV infection. This dissertation describes the characterization of one vaccine and two antiviral drug candidates against ZIKV infection. A bacterial ferritin-based nanoparticle vaccine, termed zDIII-F, is designed to display multiple copies of ZIKV E protein domain III on its surface. These stable nanoparticles are shown to induce robust antibody-mediated protection against lethal ZIKV infection in …

Prevalence And Risk Factors Associated With Multi-Drug Resistant Organisms (Mdro) Carriage Among Pediatric Patients At The Time Of Admission In A Tertiary Care Hospital Of A Developing Country. A Cross-Sectional Study, Sonia Qureshi, Noshi Maria, Mohammad Zeeshan, Seema Irfan, Farah Naz Qamar

Department of Paediatrics and Child Health

Background: The rise of Multidrug-resistant organisms (MDROs) poses a considerable burden on the healthcare systems, particularly in low-middle income countries like Pakistan. There is a scarcity of data on the carriage of MDRO particularly in the pediatrics population therefore, we aimed to determine MDRO carriage in pediatric patients at the time of admission to a tertiary care hospital in Karachi, Pakistan, and to identify the risk factors associated with it.
Methods: A cross-sectional study conducted at the pediatric department of Aga Khan University Hospital (AKUH) from May to September 2019 on 347 children aged 1-18 years. For identification of MDRO …

Draft Genome Sequences Of 13 Vibrio Cholerae Strains From The Rio Grande Delta, Jeffrey W. Turner, Jorge Duran-Gonzalez, David A. Laughlin, Daniel Unterweger, David Silva, Boris Ermolinsky, Stefan Pukatzki, Daniele Provenzano

Publications and Research

Vibrio cholerae is the etiologic agent of cholera, an acute and often fatal diarrheal disease that affects millions globally. We report the draft genome sequences of 13 non-O1/O139 V. cholerae strains isolated from the Rio Grande Delta in Texas. These genomes will aid future analyses of environmental serovars.

Respiratory Pathogens In Patients With Acute Exacerbation Of Non-Cystic Fibrosis Bronchiectasis From A Developing Country, Shayan Shahid, Kausar Jabeen, Nousheen Iqbal, Joveria Farooqi, Muhammad Irfan

Medical College Documents

Bronchiectasis unrelated to cystic fibrosis (non-CF bronchiectasis) has become a major respiratory disease in developing nations. The dilated mucus filled airways promote bacterial overgrowth followed by chronic infection, bronchial inflammation, lung injury and re-infection Accurate pathogen identification and antimicrobial susceptibility allowing appropriate treatment, in turn, may break this vicious cycle. To study the spectrum and antimicrobial spectrum of pathogen yielded from respiratory specimens in adult patients with acute exacerbation of non-cystic fibrosis (CF) bronchiectasis. This cross-sectional study was performed at the pulmonology clinics of the Aga Khan University, Karachi, Pakistan from 2016-2019. Respiratory specimens were collected from adult patients with …

Molecular Surveillance Of Drug Resistance: Plasmodium Falciparum Artemisinin Resistance Single Nucleotide Polymorphisms In Kelch Protein Propeller (K13) Domain From Southern Pakistan, Najia Karim Ghanchi, Bushra Qurashi, Hadiqa Raees, Mohammad Asim Beg

Department of Pathology and Laboratory Medicine

Background: K13 propeller (k13) polymorphism are useful molecular markers for tracking the emergence and spread of artemisinin resistance in Plasmodium falciparum. Polymorphisms are reported from Cambodia with rapid invasion of the population and almost near fixation in south East Asia. The study describes single nucleotide polymorphisms in Kelch protein propeller domain of P. falciparum associated with artemisinin resistance from Southern Pakistan.
Methods: Two hundred and forty-nine samples were collected from patients with microscopy confirmed P. falciparum malaria attending Aga Khan University Hospital during September 2015-April 2018. DNA was isolated using the whole blood protocol for the QIAmp DNA Blood Kit. …

Characterizing The Physiology And Genetics Of Contact Dependent Growth Inhibiton Systems In Burkholderia Species, Alice Elizabeth Oates

Theses and Dissertations--Microbiology, Immunology, and Molecular Genetics

Contact-dependent growth inhibition (CDI) systems mediate interbacterial competition. The genes encoding these systems are widespread among Gram-negative bacteria, including Burkholderia pathogens. CDI systems of Burkholderia species are composed of two-partner secretion pathway proteins and function to deliver the toxic C-terminus of a polymorphic surface-exposed exoprotein BcpA (Burkholderia CDI protein A) to the cytoplasm of neighboring recipient bacteria upon cell-cell contact. Specific outer and inner membrane proteins facilitate BcpA translocation both out of the donor bacterium and into the recipient cell cytoplasm. Most Burkholderia species-specific CDI translocation factors in recipient cells are unknown. BcpA intoxication functions as a mechanism by …

Comparisons Of Oral, Intestinal, And Pancreatic Bacterial Microbiomes In Patients With Pancreatic Cancer And Other Gastrointestinal Diseases, Mei Chung, Naisi Zhao, Richard Meier, Devin C. Koestler, Guojun Wu, Erika De Castillo, Bruce J. Paster, Kevin Charpentier, Jacques Izard, Karl T. Kelsey, Dominique S. Michaud

Department of Food Science and Technology: Faculty Publications

Background: Oral microbiota is believed to play important roles in systemic diseases, including cancer. Methods: We collected oral samples (tongue, buccal, supragingival, and saliva) and pancreatic tissue or intestinal samples from 52 subjects, and characterized 16S rRNA genes using high-throughput DNA sequencing.

Results: Bray–Curtis plot showed clear separations between bacterial communities in the oral cavity and those in intestinal and pancreatic tissue samples. PERMANOVA tests indicated that bacterial communities from buccal samples were similar to supragingival and saliva samples, and pancreatic duct samples were similar to pancreatic tumor samples, but all other samples were significantly different from each …

Evaluation Of Semi-Quantitative Compared To Quantitative Cultures Of Tracheal Aspirates For The Yield Of Culturable Respiratory Pathogens - A Cross-Sectional Study, Salima Rattani, Joveria Farooqi, Ghazala Jabeen, Saeeda Chandio, Qaiser Kash, Aijaz Khan, Kauser Jabeen

Department of Pathology and Laboratory Medicine

Background: Diagnosis of lower respiratory tract infections (LRTI) depends on the presence of clinical, radiological and microbiological findings. Endotracheal suction aspirate (ETSA) is the commonest respiratory sample sent for culture from intubated patients. Very few studies have compared quantitative and semi-quantitative processing of ETSA cultures for LRTI diagnosis. We determined the diagnostic accuracy of quantitative and semi-quantitative ETSA culture for LRTI diagnosis, agreement between the quantitative and semi quantitative culture techniques and the yield of respiratory pathogens with both methods.
Methods: This was a cross-sectional study conducted at the Aga Khan University clinical laboratory, Karachi, Pakistan. One hundred and seventy-eight …

Development, Expansion And Role Of Myeloid-Derived Suppressor Cells In Post-Sepsis Immune Suppression, Tuqa Alkhateeb

Electronic Theses and Dissertations

Myeloid-derived suppressor cells (MDSCs) numbers increase significantly in sepsis and are associated with high mortality rates. These myeloid cell precursors promote immunosuppression, especially in the late (post sepsis) stage. However, the mechanisms that underlie MDSC expansion and programming are not completely understood. To investigate these mechanisms, we used a cecal-ligation and puncture (CLP) mouse model of polymicrobial sepsis that progresses from an early/acute proinflammatory phase to a late/chronic immunosuppressive phase. Previous studies in our laboratory showed that microRNA (miR)-21 and miR-181b elevate levels of the transcription factor nuclear factor 1 (NFI-A) that promotes MDSC expansion. We report here that miR-21 …

Exosomes In Transmission And Blocking Of Arthropod-Borne Flaviviral Infection And Pathogenesis, Wenshuo Zhou

Biomedical Sciences Theses & Dissertations

Vector-borne diseases (VBDs) are human illnesses that are transmitted by vectors such as ticks, mosquitoes, and fleas. These arthropods transmit infectious pathogens such as viruses, protozoa, and bacteria, to humans during their blood-feeding. According to the estimation of the WHO, billions of people are affected by VBDs worldwide, and about 700,000 deaths are reported annually. Currently, very few reliable VBDs control approaches and vaccines available to treat various VBDs. Additionally, approaches to control arthropod’ proliferation and migration are difficult to develop. Furthermore, molecular determinants and mechanisms for the transmission are poorly understood. This work describes two studies identifying the novel …

Neurodevelopment Outcome Of Neonates Treated With Intraventricular Colistin For Ventriculitis Caused By Multiple Drug-Resistant Pathogens-A Case Series, Kashif Hussain, Muhammad Sohail Salat, Gul Ambreen, Javaid Iqbal

Department of Biological & Biomedical Sciences

Background: Multiple-drug-resistant Gram-negative bacteria (MDR-GNB)-associated neonatal ventriculitis is a life-threatening complication that needs timely diagnosis and effective treatment with broad-spectrum antimicrobials in critical-care settings. Inadequate penetration of antibiotics through the blood-brain barrier also demands an intraventricular (IVT) route of administration. This study reports mortality and neurodevelopmental sequelae of neonates till 18 months of age, who received IVT-colistin for treating MDR-GNB associated ventriculitis.
Methods: In a case series of seven neonates with ventriculitis due to MDR-GNB at NICU of Aga Khan University Hospital, Pakistan, between June 2015 and 2018, we reviewed IVT-colistin therapy in critically ill neonates. Treatment outcomes were assessed …

Tick-Borne Infections In New Hampshire: An Evaluation Of The Diagnostic Process In A Local Patient Population, Katherine Anderson

Honors Theses and Capstones

Overall, approximately 95 percent of reported cases of vector-borne disease were associated with ticks, making these the most medically important group of arthropods in the United States.¹ Despite the prevalence of tick-borne infections, the process for the diagnosis of this condition is not well studied. This study aims to analyze data from a pool of 100 patients who underwent testing for tick-borne disease in the same institution in Dover, New Hampshire during the most recent peak tick season of 2019. Information utilized in this study included: patient age, sex, location of testing (inpatient versus outpatient), diagnostic testing methods used …

Mucosa-Associated Microbiota In Barrett’S Esophagus, Dysplasia, And Esophageal Adenocarcinoma Differ Similarly Compared With Healthy Controls, Shajan Peter, Amanda Pendergraft,, William Vanderpol, Mel Wilcox, Kondal R. Kyanam Kabir Baig, Casey Morrow, Jacques Izard, Peter J. Mannon

Department of Food Science and Technology: Faculty Publications

Introduction: Alterations in the composition of the human gut microbiome and its metabolites have been linked to gut epithelial neoplasia. We hypothesized that differences in mucosa-adherent Barrett’s microbiota could link to risk factors, providing risk of progression to neoplasia.

Methods: Paired biopsies from both diseased and nonaffected esophagus (as well as gastric cardia and gastric juice for comparison) from patients with intestinal metaplasia (n = 10), low grade dysplasia (n = 10), high grade dysplasia (n = 10), esophageal adenocarcinoma (n = 12), and controls (n = 10) were processed for mucosa-associated bacteria …

Type 2 Bovine Viral Diarrhea Virus NPro Suppresses Type I Interferon Pathway Signaling In Bovine Cells And Augments Bovine Respiratory Syncytial Virus Replication, Abdulrahman Abdulaziz A. Alkheraif

School of Veterinary and Biomedical Sciences: Dissertations, Theses, and Student Research

Bovine viral diarrhea virus (BVDV) and bovine respiratory syncytial virus (BRSV) infections contribute to the bovine respiratory disease complex (BRDC), which is a multi-factorial disorder involving co-infections of viruses and bacteria including mycoplasma. BRDC causes great economic losses to the United States feedlot industry. BVDV infection induces immunosuppression in infected animals. BVDV N^pro binds and degrades the transcription factor interferon regulatory factor-3 (IRF-3) and effectively blocks type I interferon (type I IFN) expression in host cells. BRSV nonstructural proteins, NS1 and NS2, block activation of IRF-3. In calves, concurrent infection with BVDV and BRSV resulted in more severe clinical …

In Vitro Assay Development As An Alternative To The Use Of Laboratory Animals For Measuring Clostridium Perfingens Type C Toxoid, Lauren M. Wilmes

School of Veterinary and Biomedical Sciences: Dissertations, Theses, and Student Research

Clostridium perfringens type C produces beta toxin, which is a primary virulence determinate that can cause necrotic enteritis in neonatal animals. Vaccines directed against C. perfringens toxins have shown to be efficacious in preventing disease. However, the production of a commercial vaccine requires not only an efficacious antigen, but also testing methods for quantifying antigens and potency on final product. This research was undertaken to fulfill a need for the reduction in small animal usage to produce and deliver vaccines. The current testing methods are performed in vivo according to the Code of Federal Regulations number 9 (9CFR) United …

A Comparison Of Oral And Intravenous Mouse Models Of Listeriosis, Michelle G. Pitts, Sarah E. F. D'Orazio

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Listeria monocytogenes is one of several enteric microbes that is acquired orally, invades the gastric mucosa, and then disseminates to peripheral tissues to cause systemic disease in humans. Intravenous (i.v.) inoculation of mice with L. monocytogenes has been the most widely-used small animal model of listeriosis over the past few decades. The infection is highly reproducible and has been invaluable in deciphering mechanisms of adaptive immunity in vivo, particularly CD8+ T cell responses to intracellular pathogens. However, the i.v. model completely bypasses the gut phase of the infection. Recent advances in generating both humanized mice and murinized bacteria, as well …