In Infectious Disease Puscast #89, Drs. Daniel Griffin and Sarah Dong review recent infectious disease literature from late August to early September 2025. They discuss viral topics including the durability of Mpox antibody responses post-infection versus vaccination, the efficacy of a novel oral poliovirus vaccine in newborns, the identification of Oz virus (a Thogotovirus) as a cause of fulminant myocarditis, and baloxavir's role in reducing influenza transmission. In the bacterial section, they analyze risk factors for 30-day mortality in Pseudomonas aeruginosa bloodstream infections, the impact of a nationwide blood culture bottle shortage, and the surprising finding that common non-antibiotic medications can enhance antimicrobial resistance in E. coli. The fungal segment explores the association between candidemia duration and healthcare outcomes, and updates the changing epidemiology of blastomycosis and histoplasmosis in the US. Finally, the parasitic discussion highlights the effective biocontrol of Schistosoma mansoni snail vectors through the restoration of African catfish in Lake Victoria.
Infectious Disease Puscast #89: Literature Review and Key Insights
0:00 Welcome and Introduction: Drs. Daniel Griffin and Sarah Dong open the podcast, reviewing infectious disease literature from August 18 to September 11, 2025.
1:51 Viral Literature - Mpox Immunity: Discussion of an Open Forum Infectious Disease article showing Mpox antibody responses are sustained for two years post-infection but not after MVA-BN vaccination. Vaccinated individuals, especially those with HIV, showed significantly lower odds of retaining seropositivity, prompting calls for further research on reinfection risk and T-cell responses.
4:30 Novel Oral Polio Vaccine (OPV2) in Newborns: Review of a CID article on a Phase 2 trial in Bangladesh, demonstrating that two doses of a novel OPV2 induced strong intestinal mucosal antibody responses in healthy newborns, with 90% achieving PV2-specific neutralization by eight weeks.
6:36 Oz Virus and Fulminant Myocarditis: Sarah presents a New England Journal article detailing a case of fatal fulminant myocarditis in an elderly woman, caused by the newly identified Oz virus (a Thogotovirus) transmitted via ticks in Japan.
8:50 Baloxavir for Influenza Transmission: Discussion from a New England Journal article on a multi-country trial showing that a single dose of baloxavir significantly reduced the transmission of lab-confirmed influenza to household contacts by 29% (9.5% vs. 13.4% for placebo), though not symptom-causing transmission. Emergence of drug-resistant viruses was noted in 7.2% of index patients.
11:34 Bacterial Literature - Tree Microbiome Interlude: Daniel highlights a fascinating TWIM episode about the microbiome of trees and their production of insecticidal compounds.
12:24Pseudomonas aeruginosa Bloodstream Infections (BSIs): Review of an Infection journal study on risk factors for 30-day mortality in P. aeruginosa BSIs in Italian hospitals. Key risk factors included older age, sepsis, septic shock, and high-risk infections, while appropriate empirical therapy was the only variable associated with improved survival (39% reduced odds of death).
14:24 Blood Culture Bottle Shortage Impact: Sarah discusses a CID paper analyzing the nationwide blood culture bottle shortage in the US in 2024. Affected BD BACTEC™ facilities saw a 27.4% decrease in cultures and a 15.3% decrease in pathogen-positive patient rates, with more solitary cultures being common.
16:12 Non-Antibiotic Medications (NAMs) and AMR: Daniel presents a Nature journal article revealing that common NAMs (like ibuprofen and acetaminophen) enhance ciprofloxacin-induced mutagenesis and resistance in E. coli at gut-relevant concentrations, underscoring the overlooked role of polypharmacy in antimicrobial resistance (AMR).
19:14 Preoperative Enterosignatures and Surgical Site Infections (SSIs): Sarah introduces a OFID paper on "enterosignatures" (ESs) – patterns of rectal microbiota – that predict SSIs after abdominal surgery. A higher Firmicutes-to-Prevotella ES ratio was a significant independent predictor of SSIs, suggesting a novel biomarker for high-risk patients. Daniel suggests using this for interventions.
22:50 Fungal Literature - Candidemia Duration: Discussion of a CID study showing that candidemia lasting more than one day is associated with significantly higher in-hospital mortality (3% increase per day), longer length of stay (1 day increase), and higher hospital costs ($3,006 increase per day) compared to single-day candidemia.
24:40 Changing Epidemiology of Blastomycosis and Histoplasmosis: Review of a JID article updating the epidemiology of blastomycosis and histoplasmosis in the US from 2013-2023. Blastomycosis incidence is rising, concentrated in the upper Midwest (Minnesota, Wisconsin, Michigan), while histoplasmosis is expanding beyond the Ohio River Valley to southern states (Texas, Nebraska, Kansas, Arkansas, Louisiana, Mississippi). Older males are identified as the highest-risk demographic for both.
27:58 Parasitic Literature - Biocontrol of Schistosoma mansoni: The hosts close with a PLoS NTDs article demonstrating that restoring African catfish in Lake Victoria effectively reduced Schistosoma mansoni snail vector abundance by 57% and human infection intensity by 55%, providing a successful biological control method.
Glossary of Biological / Medical Terms:
Antibody responses: The production of proteins (antibodies) by the immune system in response to an antigen, which recognize and neutralize foreign substances like viruses or bacteria.
Antigen (vaccinia virus B5 antigen): A molecule or molecular structure from a pathogen that is recognized by the immune system and can trigger an immune response. Vaccinia virus B5 antigen is a specific protein from the vaccinia virus.
Antimicrobial Resistance (AMR): The ability of microbes (like bacteria, viruses, fungi, parasites) to resist the effects of drugs that once could kill them or inhibit their growth.
Arthralgia: Joint pain.
AV Block: Atrioventricular block, a type of heart block that occurs when the electrical signal from the heart's upper chambers (atria) to the lower chambers (ventricles) is impaired, leading to a slow or irregular heartbeat.
Baloxavir marboxil (baloxavir): An antiviral medication used to treat influenza.
Bacteroides, Firmicutes, Prevotella, Bifidobacterium, Escherichia: Genera of bacteria commonly found in the human gut, used to characterize "enterosignatures."
Biocontrol (biological control): A method of controlling pests (like disease vectors) using other living organisms.
Biomarker: A measurable indicator of some biological state or condition.
Blastomycosis: A fungal infection caused by Blastomyces species, typically affecting the lungs, skin, bones, and joints.
Bloodstream Infections (BSIs): Infections where bacteria or other microorganisms enter the bloodstream, potentially leading to sepsis.
Candidemia: A serious fungal infection caused by Candida species (yeast) in the bloodstream.
Ciprofloxacin-induced mutagenesis: The process where the antibiotic ciprofloxacin causes mutations (changes in DNA) in bacteria, potentially leading to resistance.
Cytotoxicity: The quality of being toxic to cells.
Dichroic mirrors: Optical filters that selectively pass light of a small range of colors while reflecting others, used to combine or separate different wavelengths of light.
Echinocandin: A class of antifungal medications.
Empirical therapy: Medical treatment or therapy based on clinical experience or best guess, without definitive diagnostic information.
Endomyocardial biopsy: A procedure to obtain a small sample of heart muscle tissue for examination.
Enterosignatures (ESs): A novel concept to categorize the composition of gut microbiota into distinct patterns.
E. coli (Escherichia coli): A common type of bacteria found in the intestines of humans and animals; some strains can cause illness.
Epidemiology: The study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems.
Fluorescence: The emission of light by a substance that has absorbed light or other electromagnetic radiation.
Fulminant: Developing suddenly and severely, often with rapid progression.
Fungal: Pertaining to fungi, a kingdom of organisms including yeasts, molds, and mushrooms.
GyrA, MarR, AcrR: Genes in bacteria. Mutations in these genes can lead to antimicrobial resistance, especially to ciprofloxacin.
AcrAB-TolC drug efflux pump: A bacterial system that actively pumps antibiotics and other toxic compounds out of the cell, contributing to drug resistance.
Histoplasmosis: A fungal infection caused by Histoplasma capsulatum, primarily affecting the lungs but can spread to other organs.
Hyperendemic regions: Geographic areas where a disease is consistently present at a high incidence and/or prevalence rate.
IgA (Immunoglobulin A): A type of antibody found in mucosal linings, like the intestines, playing a crucial role in local immunity.
IgG titers (Immunoglobulin G titers): A measurement of the amount of IgG antibodies in a blood sample, indicating past exposure or immunity to a pathogen.
In situ hybridization: A laboratory technique that uses a labeled complementary DNA, RNA or modified nucleic acid strand (i.e., probe) to localize a specific DNA or RNA sequence in a portion or section of tissue.
In vitro: In a test tube, culture dish, or elsewhere outside a living organism.
Incidence rate: The rate at which new cases of a disease or condition occur in a population over a specified period.
Intestinal mucosal immune responses: The immune reactions occurring in the lining of the intestines, which is critical for protection against ingested pathogens.
Length of stay (LOS): The duration of a patient's admission to a hospital or healthcare facility.
Logistics regression model: A statistical model that predicts the probability of an outcome based on one or more predictor variables.
Metagenomic next-gen sequencing: A laboratory technique used to sequence all the DNA (or RNA) from a sample, allowing identification of all microorganisms present.
Mic (Minimum Inhibitory Concentration): The lowest concentration of an antimicrobial drug that will inhibit the visible growth of a microorganism after overnight incubation.
Microbiome: The collection of all microbes (bacteria, fungi, viruses, etc.) that live in a particular environment, such as the human body or on trees.
Mpox (Monkeypox): A viral disease similar to smallpox, now referred to as Mpox.
MVA-BN vaccination (Modified Vaccinia Ankara–Bavarian Nordic vaccination): A vaccine used for Mpox, based on a modified vaccinia virus.
Mycological clearance: The elimination of fungal organisms from the bloodstream or a site of infection.
Myocarditis: Inflammation of the heart muscle.
Narrow band filters: Filters that only allow a very specific and limited range of wavelengths of light to pass through, used in fluorescence detection.
Neuraminidase inhibitors: A class of antiviral drugs that target the neuraminidase enzyme of influenza viruses.
Non-antibiotic medications (NAMs): Medications that are not antibiotics but may still affect microbial growth or resistance, such as NSAIDs, acetaminophen, etc.
Novel oral poliovirus vaccine type 2 (nOPV2): A genetically modified version of the oral poliovirus vaccine, designed to be more stable and less likely to revert to a virulent form.
OPV2 (Oral Poliovirus Vaccine type 2): A live-attenuated vaccine containing type 2 poliovirus, administered orally.
Pathogen-positive: Containing or testing positive for a disease-causing microorganism.
Peltier cooler: A thermoelectric device that transfers heat from one side to the other, used for cooling electronic components like camera sensors.
Phosphor conversion: A process where a phosphor material absorbs light of one wavelength and re-emits it at a different, usually longer, wavelength. Used in some LEDs to change the color of light.
Polypharmacy: The concurrent use of multiple medications by a patient.
Pre-operative: Before surgery.
Preventive chemotherapy: The regular administration of anti-parasitic drugs to at-risk populations to prevent disease.
Pseudomonas aeruginosa: A common bacterium that can cause a variety of infections, especially in hospitalized patients.
Rectal microbiota: The community of microorganisms (primarily bacteria) found in the rectum.
RRNA sequencing (16S rRNA sequencing): A molecular technique used to identify and classify bacteria by sequencing a specific gene (16S ribosomal RNA) found in all bacteria.
Schistosoma mansoni: A parasitic flatworm that causes schistosomiasis, transmitted through freshwater snails.
Schistosomiasis: A disease caused by parasitic worms (schistosomes) that live in the blood vessels of the bladder or intestine.
Sepsis: A life-threatening condition that arises when the body's response to an infection causes injury to its own tissues and organs.
Septic shock: A severe form of sepsis where blood pressure drops to dangerous levels and organs may begin to fail.
Seropositivity threshold: A specific level of antibodies in the blood that indicates a positive immune response or past infection.
Snail vectors: Snails that can carry and transmit disease-causing organisms.
Stool samples: Samples of feces collected for medical testing.
Surgical Site Infections (SSIs): Infections that occur at the site of a surgical incision.
T-cells: A type of white blood cell that plays a central role in cell-mediated immunity.
Thogotovirus (Oz virus): A genus of RNA viruses, some of which are transmitted by ticks and can cause illness in humans.
Transmission risk: The likelihood of a disease being passed from one individual to another.
Troponin: A protein found in heart muscle, released into the blood when heart muscle is damaged, used as a marker for myocarditis or heart attack.
Viral: Pertaining to viruses.
Whole genome sequencing: A laboratory process that determines the complete DNA sequence of an organism's genome at a single time.