mSphere® An ASM Access® Publication

Xin-Ru Wang works in tick biology and intracellular bacterial pathogenesis. In this mSphere of Influence article, she reflects on how "Gut microbiota of the tick vector Ixodes scapularis modulate colonization of the Lyme disease spirochete" by Narasimhan et al. (2014) reshaped her understanding of vector competence by placing pathogen colonization within the ecological context of the tick microbiome. Her laboratory studies Rickettsia-tick cell interactions, including autophagy, apoptosis, and...

Microorganisms, including fungi, adapt to profound changes in their local environment during human infections. After exposure to high temperature and other stress conditions, the opportunistic fungal pathogen Cryptococcus neoformans enacts changes in metabolism, cell wall structure, and transmembrane transport that allow it to survive and proliferate in a mammalian host. This stress response program is regulated by the HECT E3-ubiquitin ligase Rsp5, which is required for growth at high salinity,...

Antimicrobial resistance (AMR) poses a critical threat to global health, particularly in intensive care units, where vulnerable patients are frequently exposed to multidrug-resistant microorganisms. The human gut microbiome serves as a key reservoir for AMR genes, which can disseminate to other body sites, including the lungs, especially during severe illness. We applied Hi-C metagenomics to stool samples from 11 critically ill COVID-19 patients and analyzed microbial isolates from their lungs...

Antimicrobial resistance in Neisseria gonorrhoeae is an urgent public health threat. Resistance-guided therapy can assure appropriate treatment and reintroduce alternative therapeutic options by identifying genetic predictors of resistance. Mosaicism at codons 375-377 of the penA gene is associated with cefixime resistance. Rapid, field-deployable assays for predicting cefixime susceptibility are lacking. We used a machine-learning algorithm to develop a CRISPR Cas13a-based assay to detect the...

Aspergillus fumigatus poses a significant threat to human well-being, in part due to the increasing emergence of strains resistant to frontline antifungal therapy. In this study, we observed that the gene arvA is required for A. fumigatus morphogenesis, antifungal drug susceptibility, and cell wall homeostasis. Intriguingly, our study reveals novel morphological and growth aberrations in the absence of arvA. Loss of arvA results in hyper-swollen conidia that give rise to stunted,...

Urinary tract infections (UTIs) affect a broad patient population and inflict a substantial financial burden on the U.S. healthcare system. While uropathogenic Escherichia coli (UPEC) causes the majority of cases, other pathogens are emerging. Patient data from our healthcare system in the Gulf Coast region of Alabama revealed that Pseudomonas aeruginosa accounted for 4.0% of UTI cases, roughly double the national average, prompting further investigation into this historically understudied...

Diabetic retinopathy (DR) is the most prevalent blinding microvascular complication of diabetes mellitus. Although altered ocular surface microbiota (OSM) has been recently linked to type 2 diabetes mellitus (DM) and diabetic retinopathy (DR), its involvement in these diseases remains to be elucidated at the species level. Our current study investigated 92 conjunctival sac swabs from 28 nondiabetic controls (NC) and 64 type 2 DM patients, including 31 with DR and 33 without DR (non-DR, NDR), for...

The volatile metabolome, or volatilome, contains a wealth of information regarding individual health. Two parallel approaches can detect patterns of these volatile metabolites: chemometric analyses employing gas chromatography-mass spectrometry (GC-MS) or "noses" (trained animals or so-called electronic noses). While "noses" are exquisite odor discrimination tools, chemometric analyses are superior for determining the chemical identity of odorants related to disease conditions. Without...

Recent studies have pointed to critical roles for microbes in both exacerbation of and protection from the development of colon cancer. While much has been learned, the field remains understudied, with functional studies available for only a handful of bacteria. To identify novel microbes associated with colorectal cancer (CRC) development, we employed a preclinical chemical carcinogenesis CRC mouse model using germ-free mice that were colonized with human microbiotas. During the course of these...

Streptococcus pneumoniae is a gram-positive bacterium, colonizer of the human nasopharynx capable of causing severe invasive disease. Colonization of the nasopharynx is a prerequisite for the development of invasive disease and depends upon surface-bound bacterial proteins interacting with host cell receptors. Pneumococcal surface adhesin A (PsaA) is a highly conserved lipoprotein involved in the attachment to host airway cells via the host receptor Annexin A2 (ANXA2). However, the specific...

Pathogenic Rickettsia species are obligate intracellular bacteria that must reside in a mammalian host or arthropod vector cell to survive. Although these bacteria transition between different intracellular environments during infection, they encode few putative transcription factors, and their gene regulatory networks are largely unknown. Because of their inextricable relationship with eukaryotic cells, transcriptional profiling of the pathogen is complicated by the abundance of contaminating...

Tubulin polyglutamylation is a post-translational modification that modulates microtubule interactions with associated proteins and motor proteins, thereby contributing to the regulation of microtubule dynamics. Although its roles are well established in higher eukaryotes, the functional significance of this modification in protozoan parasites remains poorly understood. In the present study, we characterize two polyglutamylases, TTLL4C and TTLL6B, in the parasite Trypanosoma brucei, a protozoan...

The objective of this study was to describe the non-linear relationships between antimicrobial resistance to at least one tested antimicrobial (AMR) or multidrug resistance (MDR; resistance to at least three antimicrobial drug classes) of Escherichia coli isolates from calf feces and from the calf environment on dairy farms, and farm-level atmospheric variables, as well as selected calf- and herd-level factors. Data sets of 601 fecal isolates and 777 environmental isolates, collected from 57...

Low temperature remains a major bottleneck in silage fermentation, especially in cold regions and high-altitude areas. This study investigated the regulatory role of compatible solutes in enhancing the cold adaptation of Pediococcus pentosaceus OL77 and their synergistic application in oat silage under suboptimal temperatures (5°C-15°C). RT-qPCR analysis showed that expression of the cold shock protein gene CspP was sharply induced at 5°C, indicating its central role in cold-stress response....

Introduced invasive plants can alter the composition of resident soil microbial communities, which may disrupt ecosystem function and facilitate continued invasion success. Wavyleaf basketgrass (Oplismenus undulatifolius) is a high-risk, non-native invasive plant currently confined to the Mid-Atlantic United States but with the potential to colonize forest understory across the eastern United States. In this study, we characterized soil microbial communities from locations spanning the invaded...