mSphere

Thu, 11/26/2020 - 10:01
ABSTRACT Total biosynthesis or whole-cell biocatalytic production of sulfated small molecules relies on the discovery and implementation of appropriate sulfotransferase enzymes. Although fungi are prominent biocatalysts and have been used to sulfate drug-like phenolics, no gene encoding a sulfotransferase enzyme has been functionally characterized from these organisms. Here, we identify a...
Thu, 11/26/2020 - 10:01
ABSTRACT Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected over 40 million people worldwide, with over 1 million deaths as of October 2020 and with multiple efforts in the development and testing of antiviral drugs and vaccines under way. In order to gain insights into SARS-CoV-2 evolution and drug targets, we investigated how and to what extent the SARS-CoV-2 genome...
Thu, 11/26/2020 - 10:01
ABSTRACT Although most of the approximately 94 million annual human cases of gastroenteritis due to Salmonella enterica resolve without medical intervention, antimicrobial therapy is recommended for patients with severe disease. Wild birds can be natural hosts of Salmonella that pose a threat to human health; however, multiple-drug-resistant serovars of S. enterica have rarely been described. In...
Thu, 11/19/2020 - 10:01
ABSTRACT The prokaryotic adaptive immune system CRISPR/Cas serves as a defense against bacteriophage and invasive nucleic acids. A type I-E CRISPR/Cas system has been detected in classical biotype isolates of Vibrio cholerae, the causative agent of the disease cholera. Experimental characterization of this system revealed a functional immune system that operates using a 5'-TT-3' protospacer-...
Thu, 11/19/2020 - 10:01
ABSTRACT The emergence of antibiotic genetic resisters of pathogenic bacteria poses a major public health challenge. The mechanism by which bacterial antibiotic genetic resister clones formed de novo multiply and establish a resister population remained unknown. Here, we delineated the unique mode of cell division of the antibiotic genetic resisters of Mycobacterium smegmatis and Mycobacterium...
Thu, 11/12/2020 - 10:02
ABSTRACT Natural transformation is a broadly conserved mechanism of horizontal gene transfer (HGT) in bacteria that can shape their evolution through the acquisition of genes that promote virulence, antibiotic resistance, and other traits. Recent work has established that neighbor predation via type VI secretion systems, bacteriocins, and virulent phages plays an important role in promoting HGT....
Thu, 11/05/2020 - 10:02
ABSTRACT Gram-positive, spore-forming members of the Bacillus cereus group species complex are widespread in natural environments and display various degrees of pathogenicity. Recently, B. cereus group strain Bacillus mycoides Flugge ATCC 21929 was found to represent a novel lineage within the species complex, sharing a relatively low degree of genomic similarity with all B. cereus group genomes...
Thu, 10/29/2020 - 10:02
ABSTRACT Fluoroquinolones and cephalosporins are critically important antimicrobial classes for both human and veterinary medicine. We previously found a drastic increase in enrofloxacin resistance in clinical Escherichia coli isolates collected from diseased pigs from the United States over 10 years (2006 to 2016). However, the genetic determinants responsible for this increase have yet to be...
Thu, 10/29/2020 - 10:02
ABSTRACT Staphylococcus pseudintermedius is a major canine pathogen but also occasionally colonizes and infects humans. Multidrug-resistant methicillin-resistant S. pseudintermedius (MDR MRSP) strains have emerged globally, making treatment and control of this pathogen challenging. Sequence type 71 (ST71), ST68, and ST45 are the most widespread and successful MDR MRSP clones. The potential...
Thu, 10/29/2020 - 10:02
ABSTRACT Rift Valley fever virus (RVFV) is a pathogen of both humans and livestock in Africa and the Middle East. Severe human disease is associated with hepatitis and/or encephalitis. Current pathogenesis studies rely on rodents and nonhuman primates, which have advantages and disadvantages. We evaluated disease progression in Mustela putorius furo (the ferret) following intradermal (i.d.) or...
Thu, 10/22/2020 - 10:02
ABSTRACT Supply shortages of N95 respirators during the coronavirus disease 2019 (COVID-19) pandemic have motivated institutions to develop feasible and effective N95 respirator reuse strategies. In particular, heat decontamination is a treatment method that scales well and can be implemented in settings with variable or limited resources. Prior studies using multiple inactivation methods,...
Thu, 10/22/2020 - 10:02
ABSTRACT Accumulating evidence has strengthened a link between dysbiotic gut microbiota and autism. Fecal microbiota transplant (FMT) is a promising therapy to repair dysbiotic gut microbiota. We previously performed intensive FMT called microbiota transfer therapy (MTT) for children with autism spectrum disorders (ASD) and observed a substantial improvement of gastrointestinal and behavioral...
Thu, 10/22/2020 - 10:02
ABSTRACT Carbapenemase-producing Enterobacteriaceae represent a serious public health threat worldwide. Carbapenemase genes, harbored on a transferable plasmid, have been isolated globally with distinct geographical features. Klebsiella pneumoniae, included in Enterobacteriaceae, also produces carbapenemase and often shows hypervirulence. Overlapping carbapenem resistance and hypervirulence in K...
Thu, 10/08/2020 - 10:02
ABSTRACT Pseudomonas aeruginosa chronic lung infections in individuals with cystic fibrosis (CF) significantly reduce quality of life and increase morbidity and mortality. Tracking these infections is critical for monitoring patient health and informing treatments. We are working toward the development of novel breath-based biomarkers to track chronic P. aeruginosa lung infections in situ. Using...
Thu, 10/08/2020 - 10:02
ABSTRACT Shigella is the second leading cause of bacterial diarrhea worldwide. Recently, Shigella sonnei seems to be replacing Shigella flexneri in low- and middle-income countries undergoing economic development. Despite this, studies focusing on these species at the genomic level remain largely unexplored. Here, we compared the genome sequences of S. flexneri and S. sonnei isolates from India...
Thu, 10/01/2020 - 10:08
ABSTRACT The inaugural Black In Microbiology Week (#BlackInMicro) is 28 September 2020 through 4 October 2020. Its mission is to "showcase the presence and accomplishments of Black microbiologists from around the globe, connect Black microbiologists with one another and foster a sense of community among them, and provide a forum for the discussion of racial disparities in microbiology and its...
Thu, 09/24/2020 - 10:02
ABSTRACT Shigella is a major cause of moderate to severe diarrhea largely affecting children (<5 years old) living in low- and middle-income countries. Several vaccine candidates are in development, and controlled human infection models (CHIMs) can be useful tools to provide an early assessment of vaccine efficacy and potentially support licensure. A lyophilized strain of S. sonnei 53G was...
Thu, 09/24/2020 - 10:02
ABSTRACT Controlled human infection models (CHIMs) are useful for vaccine development. To improve on existing models, we developed a CHIM using a lyophilized preparation of Shigella sonnei strain 53G produced using current good manufacturing practice (cGMP). Healthy adults were enrolled in an open-label dose-ranging study. Following administration of a dose of rehydrated S. sonnei strain 53G,...
Thu, 09/17/2020 - 10:02
ABSTRACT Listeria monocytogenes is thought to colonize the brain using one of three mechanisms: direct invasion of the blood-brain barrier, transportation across the barrier by infected monocytes, and axonal migration to the brain stem. The first two pathways seem to occur following unrestricted bacterial growth in the blood and thus have been linked to immunocompromise. In contrast, cell-to-cell...
Thu, 09/17/2020 - 10:02
ABSTRACT Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a major cause of foodborne gastrointestinal illness. The adhesion of EHEC to host tissues is the first step enabling bacterial colonization. Adhesins such as fimbriae and flagella mediate this process. Here, we studied the interaction of the bacterial flagellum with the host cell’s plasma membrane using giant unilamellar vesicles...
Thu, 09/10/2020 - 10:02
ABSTRACT Multiple epidemiological studies identify Dolosigranulum pigrum as a candidate beneficial bacterium based on its positive association with health, including negative associations with nasal/nasopharyngeal colonization by the pathogenic species Staphylococcus aureus and Streptococcus pneumoniae. Using a multipronged approach to gain new insights into D. pigrum function, we observed...
Thu, 09/10/2020 - 10:02
ABSTRACT Enrofloxacin is an important antibiotic used for prevention and treatment of Salmonella infection in poultry in many countries. However, oral administration of enrofloxacin may lead to the alterations in the microbiota and metabolome in the chicken intestine, thereby reducing colonization resistance to the Salmonella infection. To study the effect of enrofloxacin on Salmonella in the...
Thu, 08/27/2020 - 10:02
ABSTRACT Cholera remains a formidable disease, and reports of multidrug-resistant strains of the causative agent Vibrio cholerae have become common during the last 3 decades. The pervasiveness of resistance determinants has largely been ascribed to mobile genetic elements, including SXT/R391 integrative conjugative elements, IncC plasmids, and genomic islands (GIs). Conjugative transfer of IncC...
Thu, 08/27/2020 - 10:02
ABSTRACT Filamentous fungi produce small cysteine-rich proteins with potent, specific antifungal activity, offering the potential to fight fungal infections that severely threaten human health and food safety and security. The genome of the citrus postharvest fungal pathogen Penicillium digitatum encodes one of these antifungal proteins, namely AfpB. Biotechnologically produced AfpB inhibited the...
Mon, 08/24/2020 - 17:36
ABSTRACT Staphylococcus aureus is a highly significant infection problem in health care centers, particularly after surgery. It has been shown that nearly 80% of S. aureus infections following surgery are the same as those in the anterior nares of patients, suggesting that the anterior nares is the source of the infection strain. This has led to the use of mupirocin ointment being applied nasally...
Thu, 08/20/2020 - 10:02
ABSTRACT Infections with multidrug-resistant bacteria often leave limited or no treatment options. The transfer of antimicrobial resistance genes (ARG) carrying plasmids between bacterial species by horizontal gene transfer represents an important mode of expansion of ARGs. Here, we demonstrate the application of Nanopore sequencing in a hospital setting for monitoring transfer and rapid...
Thu, 08/13/2020 - 10:02
ABSTRACT To understand toxin-stimulated host-pathogen interactions, we performed dual-transcriptome sequencing experiments using human epithelial (HT-29) and differentiated THP-1 (dTHP-1) immune cells infected with the sepsis-causing pathogen Vibrio vulnificus (either the wild-type [WT] pathogen or a multifunctional-autoprocessing repeats-in-toxin [MARTX] toxin-deficient strain). Gene set...
Thu, 08/06/2020 - 10:02
ABSTRACT Spore-forming bacteria of the orders Bacillales and Clostridiales play a major role in food spoilage and foodborne diseases. When environmental conditions become favorable, these spores can germinate as the germinant receptors located on the spore’s inner membrane are activated via germinant binding. This leads to the formation of vegetative cells via germination and subsequent...
Thu, 07/23/2020 - 10:01
ABSTRACT Coxiella burnetii, the causative agent of Query (Q) fever in humans, is a highly infectious obligate intracellular bacterium. Following uptake into a host cell, C. burnetii replicates within a phagolysosome-derived compartment referred to as the Coxiella-containing vacuole (CCV). During infection, C. burnetii exhibits tropism for tissues related to iron storage and recycling (e.g., the...
Thu, 07/23/2020 - 10:01
ABSTRACT The Enterobacterales order of Gram-negative bacteria includes the common nosocomial pathogens Klebsiella pneumoniae, Escherichia coli, Serratia marcescens, and Enterobacter species. Intestinal domination by some colonizing bacterial taxa is associated with subsequent infection, but 16S rRNA gene sequencing is too costly and slow to be used in a clinical setting. The objectives of this...
Thu, 07/23/2020 - 10:01
ABSTRACT Antimicrobial resistance is an ongoing issue in the treatment of typhoid fever. Resistance to first-line antimicrobials and extensively drug resistant (XDR) Salmonella Typhi isolates in Pakistan have left azithromycin as the only remaining effective oral treatment. Here, we report the emergence of organisms with a single point mutation in acrB gene, implicated in azithromycin resistance...
Thu, 07/16/2020 - 10:01
ABSTRACT The plasmid-mediated fosfomycin resistance gene fosA3 has been detected in Enterobacterales from various sources but has rarely been reported in vegetables. In this study, the aim was to investigate the prevalence of and, subsequently, to characterize fosA3-positive Enterobacterales isolates from retail vegetables. Seventeen (7.3%) fosA3-carrying strains were identified from 233 extended...
Thu, 07/16/2020 - 10:01
ABSTRACT Shigella flexneri is a major cause of bacillary dysentery in Beijing, China. The genetic features and population structure of locally circulating clones remained unclear. In this study, we sequenced the genomes of 93 S. flexneri isolates from patients in Beijing from 2005 to 2018. Phylogenetic analysis revealed a predominant lineage comprised of ST100 isolates that had acquired an...
Thu, 07/02/2020 - 10:01
ABSTRACT Spores, the infectious agents of many Firmicutes, are remarkably resilient cell forms. Even distant relatives can have similar spore architectures although some display unique features; they all incorporate protective proteinaceous envelopes. We previously found that Bacillus spores can achieve these protective properties through extensive disulfide cross-linking of self-assembled arrays...
Thu, 07/02/2020 - 10:01
ABSTRACT Since the late 1990s, changes in the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) were recognized with the emergence of community-associated MRSA (CA-MRSA). CA-MRSA belonging to clonal complex 152 (CC152), carrying the small staphylococcal cassette chromosome mec (SCCmec) type V and encoding the Panton-Valentine leukocidin (PVL), has been observed in Europe. The aim...
Thu, 06/18/2020 - 10:02
ABSTRACT Clostridium perfringens type A is involved in gas gangrene in humans and animals. Following a traumatic injury, rapid bacterial proliferation and exotoxin production result in severe myonecrosis. C. perfringens alpha toxin (CPA) and perfringolysin (PFO) are the main virulence factors responsible for the disease. Recent in vitro studies have identified an Agr-like quorum-sensing (QS)...
Thu, 06/11/2020 - 10:01
ABSTRACT There is a critical need for an improved rapid diagnostic for enteric fever. We have previously demonstrated that serum IgA responses targeting Salmonella enterica serovar Typhi hemolysin E (HlyE) and lipopolysaccharide (LPS) are able to discriminate patients with acute typhoid from healthy controls in areas where enteric fever is endemic (healthy endemic controls) and from patients with...
Thu, 06/11/2020 - 10:01
ABSTRACT Salmonella comprises more than 2,600 serovars. Very few environmental and uncommon serovars have been characterized for their potential role in virulence and human infections. A complementary in vitro and in vivo systematic high-throughput analysis of virulence was used to elucidate the association between genetic and phenotypic variations across Salmonella isolates. The goal was to...
Thu, 05/28/2020 - 03:37
ABSTRACT Agricultural use of antibiotics is recognized by the U.S. Centers for Disease Control and Prevention as a major contributor to antibiotic-resistant infections. While most One Health attention has been on the potential for antibiotic resistance transmission from livestock and contaminated meat products to people, plant foods are fundamental to the food chain for meat eaters and...
Thu, 05/28/2020 - 03:37
ABSTRACT Syndiniales are a ubiquitous group of protist parasites that infect and kill a wide range of hosts, including harmful bloom-forming dinoflagellates. Despite the importance of parasitism as an agent of plankton mortality, parasite-host dynamics remain poorly understood, especially over time, hindering the inclusion of parasitism in food web and ecosystem models. For a full year in the...
Thu, 05/28/2020 - 03:37
ABSTRACT Salmonella enterica serovar Newport (S. Newport) infections are gradually on the rise in China from the last decade. For humans’ infections, S. Newport has been ranked among the top five serovars responsible for persistent infections, globally. A total of 290 S. Newport strains with their relevant clinical metadata were analyzed, and the strains were subjected to whole-genome...
Thu, 05/21/2020 - 03:36
ABSTRACT Brucella canis is a Gram-negative, facultative intracellular bacterium and the causative agent of canine brucellosis, a highly contagious disease of dogs that can be transmitted to humans. Unfortunately, no vaccine is available to prevent infection. We recently characterized the kinetics of B. canis infection in the mouse model, establishing the required dose necessary to achieve...
Thu, 05/14/2020 - 03:33
ABSTRACT As a natural host species for Brucella melitensis, pregnant sheep offer an ideal model to evaluate vaccine candidates for safety. B. melitensis strain Rev. 1 has been used almost exclusively to prevent brucellosis in small ruminants, but it causes abortions when given to pregnant animals. To evaluate the comparative safety of the candidate Brucella melitensis 16MvjbR, pregnant sheep (n...
Thu, 05/07/2020 - 03:32
ABSTRACT Aspergillus flavus, a ubiquitous and saprophytic fungus, is the second most common cause of aspergillosis worldwide. Several mechanisms contribute to the establishment of the fungal infection. Extracellular vesicles (EVs) have been described as "virulence factor delivery bags" in several fungal species, demonstrating a crucial role during the infection. In this study, we evaluated...
Thu, 05/07/2020 - 03:32
ABSTRACT The clostridial neurotoxins (CNTs) comprise tetanus toxin (TT) and botulinum neurotoxin (BoNT [BT]) serotypes (A to G and X) and several recently identified CNT-like proteins, including BT/En and the mosquito BoNT-like toxin Pmp1. CNTs are produced as single proteins cleaved to a light chain (LC) and a heavy chain (HC) connected by an interchain disulfide bond. LC is a zinc...
Thu, 04/30/2020 - 03:35
ABSTRACT A recent clinical report has linked Streptococcus pyogenes β-lactam antibiotic resistance to mutation in the penicillin binding protein (PBP) PBP2x. To determine whether this is an isolated case or reflects a broader prevalence of mutations that might confer reduced β-lactam susceptibility, we investigated the relative frequency of PBP sequence variation within a global...
Thu, 04/16/2020 - 03:24
ABSTRACT This study identified and characterized extended-spectrum-β-lactamase-producing Enterobacteriaceae (ESBL-E) and carbapenemase-producing Enterobacteriaceae (CPE) from farmed freshwater fish and pig offal procured from the wet markets across Hong Kong. During March 2018 to January 2019, 730 food animal samples, namely, 213 snakehead fish, 198 black carp, and 339 pig organs, were...
Thu, 04/16/2020 - 03:24
ABSTRACT Two separate human outbreaks of Salmonella enterica serotype Reading occurred between 2017 and 2019 in the United States and Canada, and both outbreaks were linked to the consumption of raw turkey products. In this study, a comprehensive genomic investigation was conducted to reconstruct the evolutionary history of S. Reading from turkeys and to determine the genomic context of outbreaks...
Thu, 04/09/2020 - 03:26
ABSTRACT Carbapenemase-producing Enterobacterales (CPE) have become an important public health concern. In our hospital, VIM enzymes were first detected in 2005, Klebsiella pneumoniae carbapenemase (KPC) enzymes in 2009, and OXA-48 enzymes in 2012. We assess the population biology of the first OXA-48-producing Enterobacterales isolates recovered in our hospital (2012 to 2013) where infections by...
Thu, 04/02/2020 - 03:22
ABSTRACT Enterotoxigenic Escherichia coli (ETEC) is a major diarrheal pathogen in children in low- to middle-income countries. Previous studies have identified heat-stable enterotoxin (ST)-producing ETEC as one of the major diarrhea-causing pathogens in children younger than five years. In this study, we examined iron and zinc binding by both human and porcine ST variants and determined how host...

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