mBio® An ASM Access® Publication

Ensitrelvir is an antiviral drug that specifically targets the conserved main protease (M^(pro)) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, mutations in M^(pro) could confer resistance to antivirals, including ensitrelvir. Thus, identifying SARS-CoV-2 drug-resistant mutants and elucidating their mechanisms of resistance are critical for guiding the selection of effective antiviral therapies. Here, we utilized a recombinant luminescent attenuated SARS-CoV-2 lacking...

Mineralized external structures have evolved independently across unicellular eukaryotes. Within the phylum Ciliophora, this trait's restriction to the family Colepidae makes it an ideal model for dissecting the genomic basis of this innovation. Here, we assembled high-quality macronuclear genomes for three Colepidae species (Coleps hirtus, Levicoleps biwae, and Coleps viridis), and uncovered a marked expansion of gene families implicated in calcium carbonate biomineralization. Phylogenetic...

Klebsiella pneumoniae is a prominent pathogen causing life-threatening bloodstream infections. Although biofilm formation and resistance to human serum are well-recognized virulence traits, their interrelatedness during K. pneumoniae bloodstream infections remains unclear. Here, we hypothesize that biofilm production is related to K. pneumoniae's ability to thrive in human serum and, therefore, may predict the strains' ability for serum survival. We analyzed 57 clinical, genetically diverse...

The global spread of Mycobacterium tuberculosis (MTB) is facilitated by airborne transmission, a low infectious dose, and the pathogen's ability to persist in a latent state. Despite sharing over 99% genomic identity, MTB strains and lineages show significant variability in transmissibility. We hypothesized that natural polymorphisms in the two-component regulatory system (TCS) PhoP-PhoR (PhoPR), a major virulence regulator, contribute to this variability.First, we identified zinc and cadmium as...

Persistent papillomavirus infection is a key driver of neoplastic progression in both mucosal and cutaneous epithelia. Although estrogen is a well-established cofactor in HPV-associated cervical carcinogenesis, its role in cutaneous papillomavirus disease has remained poorly understood. Using a murine papillomavirus type 1 (MmuPV1) infection model in immunocompetent FVB/N mice, we investigated whether estrogen influences viral pathogenesis in infected cutaneous epithelia. Estrogen treatment...

Atrial fibrillation (AF) is the most prevalent clinical arrhythmia, associated with numerous complications, elevated morbidity and mortality rates, and limited therapeutic interventions, which have been confirmed to be related to the intestinal microbiota. However, there is currently limited research on the interaction between gut microbiota and AF. Herein, we integrated the largest Chinese gut microbiota cohort (n = 355) related to AF to date and identified a marked microbial imbalance in AF...

Spring viremia of carp virus (SVCV), an aquatic rhabdovirus, causes lethal disease and major economic losses in carp aquaculture, yet no licensed antivirals are available. In this study, we identify the plant-derived diterpenoid quinone cryptotanshinone (CPT) as a potent inhibitor of SVCV that acts by inhibiting clathrin-mediated endocytosis (CME) and attenuating early mitochondrial apoptosis. CPT was well tolerated by epithelioma papulosum cyprinid cells (50% cytotoxic concentration [CC(50)] =...

Polyamines integrate metabolism with innate immunity; however, their antibacterial roles remain unresolved. Here, we show that spermine suppresses innate immune responses against Salmonella enterica serovar Typhimurium infection in macrophages. Exogenous spermine blunted pro-inflammatory responses and increased intracellular bacterial burden in vitro and in vivo. Pharmacologic depletion or back-conversion of endogenous polyamines enhanced pro-inflammatory responses, revealing an intrinsic brake....

Antibiotic exposure during infancy disrupts gut microbiome assembly during a critical developmental window. Strategies to restore these ecosystems remain limited. In the REPAIR trial (NCT06609980), eight infants were followed longitudinally; two received amoxicillin for otitis media, and one subsequently underwent autologous fecal microbiota transplantation (aFMT) using stool collected prior to antibiotic exposure. Shotgun metagenomics, Hi-C-assisted resistome profiling, and untargeted...

Coccidioidomycosis is a pulmonary disease caused by the dimorphic fungus Coccidioides, which is endemic to the southwestern United States and South America. Coccidioides grows as septate hyphae in soil and forms spores that can become airborne during mechanical disruption of the soil. In the lungs, the inhaled spores develop into large multinucleated spherules, a unique morphology among medically important Coccidioides species, and reproduce by endosporulation. A hallmark of the host immune...

Conservons are operons that encode unusual regulatory systems found in bacteria of the phylum Actinomycetota. These regulatory systems are composed of four core proteins: a sensor histidine kinase-like protein (CvnA homolog), an MglB-type roadblock protein (CvnB homolog), a protein containing a domain of unknown function (CvnC homolog), and a small Ras-like GTPase (CvnD homolog). Based on their conserved small GTPase components and their phylogenetic distribution, we propose that the systems...

Invasive mold diseases (IMDs) such as mucormycosis and aspergillosis carry high mortality despite optimal antifungal therapy. Adjunctive immunomodulation, including anti-PD-1 antibodies and interferon-γ, may help restore antifungal immunity in severely ill patients. We implemented multidisciplinary team meetings in France to assess and validate the use of adjunctive anti-PD-1 monoclonal antibodies and interferon-γ in combination with antifungal therapy for patients with life-threatening IMDs....

Many pathogens target the host actin cytoskeleton through the delivery of actin depolymerizing toxins, including mono-ADP-ribosyltransferases (mART), ultimately triggering host cell death. Despite the importance of mARTs in pathogen virulence, it remains unclear whether actin ribosylation is required for mART-dependent cell death, and how actin depolymerization leads to cell death. Using the non-typhoidal Salmonella enterica Typhimurium-encoded mART, SpvB, we report that cell death is induced...

Nakaseomyces glabratus (formerly Candida glabrata) is a leading cause of invasive candidiasis and rapidly develops antifungal drug resistance during treatment. An increasing number of clinical isolates show reduced susceptibility to echinocandins and azoles, leaving amphotericin B (AMB) as a last therapeutic option. Resistance of N. glabratus to this drug is rare, and its underlying mechanisms are still not fully understood. Here, we describe two independent multidrug-resistant bloodstream...

Lipid droplets (LDs) and small extracellular vesicles (sEVs) are classically known for lipid metabolism and intercellular communication, respectively. Here, we reveal a mechanistic connection between LD dynamics and sEV-mediated non-lytic release of Japanese encephalitis virus (JEV) from neuronal cells. Using Neuro2A, SHSY-5Y, N9 microglia, and primary cortical neurons, we show that JEV is packaged within sEVs (~200 nm) through an ESCRT-independent, neutral sphingomyelinase 2...