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Microbiology Spectrum Aug 2023Plasmid-mediated quinolone resistance (PMQR) determinants, such as genes, have been widely reported in spp. while other types of PMQR genes were rarely reported in...
Plasmid-mediated quinolone resistance (PMQR) determinants, such as genes, have been widely reported in spp. while other types of PMQR genes were rarely reported in these bacteria. This study characterized the phenotypic and genotypic features of foodborne spp. carrying , a key PMQR gene in . Among a total of 1,811 foodborne isolates tested, 34 (1.88%) were found to harbor the gene. The allele was the most prevalent, but coexistence with other alleles was common. Missense mutations in the quinolone resistance-determining region (QRDR) of the and genes were only found in 11 of the 34 -bearing isolates. Antimicrobial susceptibility tests showed that all 34 -bearing isolates were resistant to ampicillin and that a high percentage also exhibited resistance to cefotaxime, ceftriaxone, and trimethoprim-sulfamethoxazole. Genetic analysis showed that these phenotypes were attributed to a diverse range of resistance elements that the -bearing isolates harbored. The gene could be found in both the chromosome and plasmids; the plasmid-borne genes could be found on both conjugative and nonconjugative plasmids. pAQU-type -bearing conjugative plasmids were able to mediate expression of phenotypic resistance to both ciprofloxacin and cephalosporins. Transmission of this plasmid among spp. would speed up the emergence of multidrug-resistant (MDR) pathogens that are resistant to the most important antibiotics used in treatment of infections, suggesting that close monitoring of emergence and dissemination of MDR spp. in both food samples and clinical settings is necessary. spp. used to be very susceptible to antibiotics. However, resistance to clinically important antibiotics, such as cephalosporins and fluoroquinolones, among clinically isolated strains is increasingly common. In this study, we found that plasmid-mediated quinolone resistance (PMQR) genes, such as , that have not been previously reported in spp. can now be detected in food isolates. The gene alone could mediate expression of ciprofloxacin resistance in spp.; importantly, this gene could be found in both the chromosome and plasmids. The plasmids that harbor the gene could be both conjugative and nonconjugative, among which the pAQU-type -bearing conjugative plasmids were able to mediate expression of resistance to both ciprofloxacin and cephalosporins. Transmission of this plasmid among spp. would accelerate the emergence of multidrug-resistant pathogens.
Topics: Ciprofloxacin; Cephalosporins; Drug Resistance, Bacterial; Anti-Bacterial Agents; Quinolones; Plasmids; Monobactams; Vibrio; Microbial Sensitivity Tests
PubMed: 37395663
DOI: 10.1128/spectrum.01032-23 -
MBio Oct 2023Many free-swimming bacteria propel themselves through liquid using rotary flagella, and mounting evidence suggests that the inhibition of flagellar rotation initiates...
Many free-swimming bacteria propel themselves through liquid using rotary flagella, and mounting evidence suggests that the inhibition of flagellar rotation initiates biofilm formation, a sessile lifestyle that is a nearly universal surface colonization paradigm in bacteria. In general, motility and biofilm formation are inversely regulated by the intracellular second messenger bis-(3´-5´)-cyclic dimeric guanosine monophosphate (c-di-GMP). Here, we identify a protein, PlzD, bearing a conserved c-di-GMP binding PilZ domain that localizes to the flagellar pole in a c-di-GMP-dependent manner and alters the foraging behavior, biofilm, and virulence characteristics of the opportunistic human pathogen, . Our data suggest that PlzD interacts with components of the flagellar stator to decrease bacterial swimming speed and changes in swimming direction, and these activities are enhanced when cellular c-di-GMP levels are elevated. These results reveal a physical link between a second messenger (c-di-GMP) and an effector (PlzD) that promotes transition from a motile to a sessile state in .
Topics: Humans; Vibrio vulnificus; Bacterial Proteins; Virulence; Cyclic GMP; Biofilms; Gene Expression Regulation, Bacterial
PubMed: 37800901
DOI: 10.1128/mbio.01536-23 -
Frontiers in Cellular and Infection... 2023, a foodborne pathogen, has a high mortality rate. Despite its relevance to public health, the identification of virulence genes associated with the pathogenicity of...
, a foodborne pathogen, has a high mortality rate. Despite its relevance to public health, the identification of virulence genes associated with the pathogenicity of currently known clinical isolates of is incomplete and its synergistic pathogenesis remains unclear. Here, we integrate whole genome sequencing (WGS), genome-wide association studies (GWAS), and genome-wide epistasis studies (GWES), along with phenotype characterization to investigate the pathogenesis and survival strategies of . GWAS and GWES identified a total of six genes (, , , , , and ) associated with the pathogenicity of clinical isolates related to nucleotide/amino acid transport and metabolism, cell membrane biogenesis, signal transduction mechanisms, and protein turnover. Of these, five were newly discovered potential specific virulence genes of in this study. Furthermore, GWES combined with phenotype experiments indicated that isolates were clustered into two ecological groups (EGs) that shared distinct biotic and abiotic factors, and ecological strategies. Our study reveals pathogenic mechanisms and their evolution in to provide a solid foundation for designing new vaccines and therapeutic targets.
Topics: Metagenomics; Vibrio vulnificus; Genome-Wide Association Study; Amino Acids; Biological Transport
PubMed: 37692161
DOI: 10.3389/fcimb.2023.1254379 -
Biology Jul 2023The symbiosis between cnidarians and dinoflagellates underpins the success of reef-building corals in otherwise nutrient-poor habitats. Alterations to symbiotic state...
The symbiosis between cnidarians and dinoflagellates underpins the success of reef-building corals in otherwise nutrient-poor habitats. Alterations to symbiotic state can perturb metabolic homeostasis and thus alter the release of biogenic volatile organic compounds (BVOCs). While BVOCs can play important roles in metabolic regulation and signalling, how the symbiotic state affects BVOC output remains unexplored. We therefore characterised the suite of BVOCs that comprise the volatilome of the sea anemone ('Aiptasia') when aposymbiotic and in symbiosis with either its native dinoflagellate symbiont or the non-native symbiont . In parallel, the bacterial community structure in these different symbiotic states was fully characterised to resolve the holobiont microbiome. Based on rRNA analyses, 147 unique amplicon sequence variants (ASVs) were observed across symbiotic states. Furthermore, the microbiomes were distinct across the different symbiotic states: bacteria in the family Vibrionaceae were the most abundant in aposymbiotic anemones; those in the family Crocinitomicaceae were the most abundant in anemones symbiotic with ; and anemones symbiotic with had the highest proportion of low-abundance ASVs. Across these different holobionts, 142 BVOCs were detected and classified into 17 groups based on their chemical structure, with BVOCs containing multiple functional groups being the most abundant. Isoprene was detected in higher abundance when anemones hosted their native symbiont, and dimethyl sulphide was detected in higher abundance in the volatilome of both Aiptasia-Symbiodiniaceae combinations relative to aposymbiotic anemones. The volatilomes of aposymbiotic anemones and anemones symbiotic with were distinct, while the volatilome of anemones symbiotic with overlapped both of the others. Collectively, our results are consistent with previous reports that produces a metabolically sub-optimal symbiosis with Aiptasia, and add to our understanding of how symbiotic cnidarians, including corals, may respond to climate change should they acquire novel dinoflagellate partners.
PubMed: 37508443
DOI: 10.3390/biology12071014 -
Microbiology Spectrum Dec 2023As a severe emerging shrimp disease, TPD has heavily impacted the shrimp aquaculture industry and resulted in serious economic losses in China since spring 2020. This...
As a severe emerging shrimp disease, TPD has heavily impacted the shrimp aquaculture industry and resulted in serious economic losses in China since spring 2020. This study aimed to identify the key virulent factors and related genes of the , for a better understanding of its pathogenicity of the novel highly lethal infectious pathogen, as well as its molecular epidemiological characteristics in China. The present study revealed that a novel protein, high virulent protein-2 (MW >100 kDa), is responsible to the lethal virulence of to shrimp post-larvae. The results are essential for effectively diagnosing and monitoring novel pathogenic bacteria, like , in aquaculture shrimps and would be beneficial to the fisheries department in early warning of emergence and developing prevention strategies to reduce economic losses due to severe outbreaks of TPD. Elucidation of the key virulence genes and genomics of could also provide valuable information on the evolution and ecology of this emerging pathogen in aquaculture environments.
Topics: Virulence Factors; Vibrio parahaemolyticus; Virulence; Bacterial Proteins; Aquaculture
PubMed: 37850796
DOI: 10.1128/spectrum.00492-23 -
Microbiology Spectrum Aug 2023Vibrio parahaemolyticus is a bacterial pathogen that becomes lethal to shrimps when acquiring the pVA1-type plasmid carrying the PirAB genes, causing acute...
Vibrio parahaemolyticus is a bacterial pathogen that becomes lethal to shrimps when acquiring the pVA1-type plasmid carrying the PirAB genes, causing acute hepatopancreatic necrosis disease (AHPND). This disease causes significant losses across the world, with outbreaks reported in Southeast Asia, Mexico, and South America. Virulence level and mortality differences have been reported in isolates from different locations, and whether this phenomenon is caused by plasmid-related elements or genomic-related elements from the bacteria remains unclear. Here, nine genomes of South American AHPND-causing V. parahaemolyticus (VP) isolates were assembled and analyzed using a comparative genomics approach at (i) whole-genome, (ii) secretion system, and (iii) plasmid level, and then included for a phylogenomic analysis with another 86 strains. Two main results were obtained from our analyses. First, all isolates contained pVA1-type plasmids harboring the toxin coding genes, and with high similarity with the prototypical sequence of Mexican-like origin, while phylogenomic analysis showed some level of heterogeneity with discrete clusters and wide diversity compared to other available genomes. Second, although a high genomic similarity was observed, variation in virulence genes and clusters was observed, which might be relevant in the expression of the disease. Overall, our results suggest that South American pathogenic isolates are derived from various genetic lineages which appear to have acquired the plasmid through horizontal gene transfer. Furthermore, pathogenicity seems to be a multifactorial trait where the degree of virulence could be altered by the presence or variations of several virulence factors. AHPND have caused losses of over $2.6 billion to the aquaculture industry around the world due to its high mortality rate in shrimp farming. The most common etiological agent is V. parahaemolyticus strains possessing the pVA1-type plasmid carrying the PirAB toxin. Nevertheless, complete understanding of the role of genetic elements and their impact in the virulence of this pathogen remains unclear. In this work, we analyzed nine South American AHPND-causing V. parahaemolyticus isolates at a genomic level, and assessed their evolutionary relationship with other 86 strains. We found that all our isolates were highly similar and possessed the Mexican-type plasmid, but their genomic content did not cluster with other Mexican strains, but instead were spread across all isolates. These results suggest that South American VP have different genetic backgrounds, and probably proceed from diverse geographical locations, and acquire the pVA1-type plasmid via horizontal gene transfer at different times.
Topics: Humans; Vibrio parahaemolyticus; Plasmids; Toxins, Biological; Genomics; Aquaculture; Necrosis
PubMed: 37272817
DOI: 10.1128/spectrum.04851-22 -
Viruses Jul 2023Cholera, caused by pathogenic , poses a significant public health risk through water and food transmission. Biofilm-associated plays a crucial role in seasonal cholera...
Cholera, caused by pathogenic , poses a significant public health risk through water and food transmission. Biofilm-associated plays a crucial role in seasonal cholera outbreaks as both a reservoir in aquatic environments and a direct source of human infection. Although VP3, a lytic phage, shows promise in eliminating planktonic from the aquatic environment, its effectiveness against biofilm-associated is limited. To address this limitation, our proposed approach aims to enhance the efficacy of VP3 in eliminating biofilm-associated by augmenting the availability of phage receptors on the surface of . TolC is a receptor of VP3 and a salt efflux pump present in many bacteria. In this study, we employed NaCl as an enhancer to stimulate TolC expression and observed a significant enhancement of TolC expression in both planktonic and biofilm cells of . This enhancement led to improved adsorption of VP3. Importantly, our findings provide strong evidence that high salt concentrations combined with VP3 significantly improve the elimination of biofilm-associated . This approach offers a potential strategy to eliminate biofilm-formation bacteria by enhancing phage-host interaction.
Topics: Vibrio cholerae; Bacteriophages; Sodium Chloride; Transcription, Genetic; Biofilms; Cholera
PubMed: 37631982
DOI: 10.3390/v15081639 -
Infection and Immunity Sep 2023In its natural aquatic environment, the bacterial pathogen , the causative agent of the enteric disease cholera, is in constant competition with bacterial viruses known...
In its natural aquatic environment, the bacterial pathogen , the causative agent of the enteric disease cholera, is in constant competition with bacterial viruses known as phages. Following ICP3 infection, cultures that exhibited phage killing always recovered overnight, and clones isolated from these regrowth populations exhibited complete resistance to subsequent infections. Whole-genome sequencing of these resistant mutants revealed seven distinct mutations in genes encoding for enzymes involved in O1 antigen biosynthesis, demonstrating that the O1 antigen is a previously uncharacterized putative receptor of ICP3. To further elucidate the specificity of the resistance conferred by these mutations, they were challenged with the -specific phages ICP1 and ICP2. All seven O1 antigen mutants demonstrated pan-resistance to ICP1 but not ICP2, which utilizes the OmpU outer membrane protein as a receptor. We show that resistant mutations to ICP1 and ICP3 evolve at a significantly higher frequency than ICP2, but these mutations have a significant fitness tradeoff to and are unable to evolve in the presence of an antimicrobial that mimics host cell defensins.
Topics: Humans; Vibrio cholerae; Cholera; Bacteriophages; Environment; Membrane Proteins
PubMed: 37594274
DOI: 10.1128/iai.00026-23 -
MBio Aug 2023Microbiome manipulation is gaining fresh attention as a way to mitigate diseases in aquaculture. The commercially farmed seaweed suffers from a bacterial-induced...
Microbiome manipulation is gaining fresh attention as a way to mitigate diseases in aquaculture. The commercially farmed seaweed suffers from a bacterial-induced bleaching disease, which has major implications for the reliable supply of healthy sporelings. Here, we identify a beneficial bacterium, X-2 that significantly reduces the risk of bleaching disease. By combining infection assays and multi-omic analyses, we provide evidence to suggest that the underlying protective mechanisms of X-2 involve maintaining epibacterial communities, increasing the gene expression of related to immune and stress protection pathways, and stimulating betaine concentrations in holobionts. Thus, X-2 can elicit a suite of microbial and host responses to mitigate the bleaching disease. Our study provides insights into disease control in farmed through the application of beneficial bacteria. IMPORTANCE Beneficial bacteria can elicit a suite of microbial and host responses to enhance the resistance to bleaching disease.
Topics: Vibrio alginolyticus; Seaweed; Bacteria; Microbiota; Aquaculture
PubMed: 37310733
DOI: 10.1128/mbio.00065-23 -
Nature Communications Jul 2023Bacteria swim using a flagellar motor that is powered by stator units. Vibrio spp. are highly motile bacteria responsible for various human diseases, the polar flagella...
Bacteria swim using a flagellar motor that is powered by stator units. Vibrio spp. are highly motile bacteria responsible for various human diseases, the polar flagella of which are exclusively driven by sodium-dependent stator units (PomAB). However, how ion selectivity is attained, how ion transport triggers the directional rotation of the stator unit, and how the stator unit is incorporated into the flagellar rotor remained largely unclear. Here, we have determined by cryo-electron microscopy the structure of Vibrio PomAB. The electrostatic potential map uncovers sodium binding sites, which together with functional experiments and molecular dynamics simulations, reveal a mechanism for ion translocation and selectivity. Bulky hydrophobic residues from PomA prime PomA for clockwise rotation. We propose that a dynamic helical motif in PomA regulates the distance between PomA subunit cytoplasmic domains, stator unit activation, and torque transmission. Together, our study provides mechanistic insights for understanding ion selectivity and rotor incorporation of the stator unit of the bacterial flagellum.
Topics: Humans; Bacterial Proteins; Sodium; Cryoelectron Microscopy; Vibrio alginolyticus; Flagella; Molecular Motor Proteins
PubMed: 37500658
DOI: 10.1038/s41467-023-39899-z