-
PLoS Biology Aug 2023Antibiotic resistance is a continuously increasing concern for public healthcare. Understanding resistance mechanisms and their emergence is crucial for the development...
Antibiotic resistance is a continuously increasing concern for public healthcare. Understanding resistance mechanisms and their emergence is crucial for the development of new antibiotics and their effective use. The peptide antibiotic albicidin is such a promising candidate that, as a gyrase poison, shows bactericidal activity against a wide range of gram-positive and gram-negative bacteria. Here, we report the discovery of a gene amplification-based mechanism that imparts an up to 1000-fold increase in resistance levels against albicidin. RNA sequencing and proteomics data show that this novel mechanism protects Salmonella Typhimurium and Escherichia coli by increasing the copy number of STM3175 (YgiV), a transcription regulator with a GyrI-like small molecule binding domain that traps albicidin with high affinity. X-ray crystallography and molecular docking reveal a new conserved motif in the binding groove of the GyrI-like domain that can interact with aromatic building blocks of albicidin. Phylogenetic studies suggest that this resistance mechanism is ubiquitous in gram-negative bacteria, and our experiments confirm that STM3175 homologs can confer resistance in pathogens such as Vibrio vulnificus and Pseudomonas aeruginosa.
Topics: Gene Amplification; Anti-Bacterial Agents; Molecular Docking Simulation; Phylogeny; Gram-Negative Bacteria; Gram-Positive Bacteria
PubMed: 37561817
DOI: 10.1371/journal.pbio.3002186 -
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 -
NPJ Vaccines Sep 2023Flagellin, the TLR5 agonist, shows potent adjuvant activities in diverse vaccines and immunotherapies. Vibrio vulnificus flagellin B expressed in eukaryotic cells...
Flagellin, the TLR5 agonist, shows potent adjuvant activities in diverse vaccines and immunotherapies. Vibrio vulnificus flagellin B expressed in eukaryotic cells (eFlaB) could not stimulate TLR5 signaling. Enzymatic deglycosylation restored eFlaB's TLR5 stimulating functionality, suggesting that glycosylation interferes with eFlaB binding to TLR5. Site-directed mutagenesis of N-glycosylation residues restored TLR5 stimulation and adjuvanticity. Collectively, deglycosylated eFlaB may provide a built-in adjuvant platform for eukaryotic-expressed antigens and nucleic acid vaccines.
PubMed: 37752138
DOI: 10.1038/s41541-023-00738-3 -
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 -
Frontiers in Microbiology 2023is an opportunistic, global pathogen that naturally inhabits sea water and is responsible for most vibriosis-related deaths. We investigated the genetic characteristics...
is an opportunistic, global pathogen that naturally inhabits sea water and is responsible for most vibriosis-related deaths. We investigated the genetic characteristics of isolated from the clinical blood culture specimen of a patient with hepatitis B virus cirrhosis in 2018 (named as VV2018) by whole genome sequencing (WGS). VV2018 belonged to a novel sequencing type 620 (ST620) and comprised two circular chromosomes, containing 4,389 potential coding sequences (CDSs) and 152 RNA genes. The phylogenetic tree of single nucleotide polymorphisms (SNPs) using 26 representative genomes revealed that VV2108 grouped with two other strains isolated from humans. The pan-genome of was constructed using 26 representative genomes to elucidate their genetic diversity, evolutionary characteristics, and virulence and antibiotic resistance profiles. The pan-genome analysis revealed that VV2018 shared a total of 3,016 core genes (≥99% presence), including 115 core virulence factors (VFs) and 5 core antibiotic resistance-related genes, and 309 soft core genes (≥95 and <99% presence) with 25 other strains. The gene might account for the cefazolin resistance, and comparative analysis of the genetic context of revealed that two genes upstream and downstream of were conserved. The glycosylation () like genes were found in VV2018 compared with Pgl-related proteins in that might affect the adherence of the strain in hosts. The comparative analysis of VV2018 would contribute to a better understanding of the virulence and antibiotic resistance profiles of . Meanwhile much work remains to be done to better understand the function of -like genes in .
PubMed: 38029170
DOI: 10.3389/fmicb.2023.1240835 -
Frontiers in Microbiology 2023Fluctuations in environmental physicochemical parameters can affect the diversity and prevalence of microbial communities, including vibrios, associated with aquatic...
INTRODUCTION
Fluctuations in environmental physicochemical parameters can affect the diversity and prevalence of microbial communities, including vibrios, associated with aquatic species and their surrounding environments. This study aimed to investigate the population dynamics of two species as well as the microbial community diversity of whole crab and seawater from the Maryland Coastal Bays (MCBs), using 16S rRNA sequencing.
METHODS
During this study, three crabs and 1 L of seawater were collected monthly from two sites for 3 months. Crab tissue was extracted and pooled for each site. Extracted crab tissue and seawater were analyzed for and using Most Probable Number (MPN) real-time PCR. For 16S rRNA microbiome analysis, three different DNA extraction kits were evaluated to extract microbial DNA from individual crabs. Also, 500 mL of each seawater sample was filtered for DNA extraction.
RESULTS
Results indicated that sample types and sampling periods had a significant effect on the alpha diversity of the microbial community of crabs and seawater ( < 0.05); however, no statistical difference was found between DNA extraction kits. Beta diversity analysis also found that the microbial compositions between sample types and temporal distributions were statistically significant. Taxonomic classification revealed that Proteobacteria, Cyanobacteria, Actinobacteria, and Bacteroidetes were present in both crab and seawater samples. and were also detected in both crab and seawater samples, although crabs contained a higher concentration of the bacterium compared to the seawater samples. It was found that vibrios were not a dominant species in the microbial community of crab or seawater samples.
DISCUSSION
Results from this study provide further insight into species diversity and phylogenetic compositions of blue crabs and seawater from the MCBs. These approaches will help in risk assessments that are essential in the overall advancement of public health.
PubMed: 37854338
DOI: 10.3389/fmicb.2023.1235070 -
Microbiology Spectrum May 2024is a genus of halophilic, gram-negative bacteria found in estuaries around the globe. Integral parts of coastal cultures often involve contact with vectors of...
UNLABELLED
is a genus of halophilic, gram-negative bacteria found in estuaries around the globe. Integral parts of coastal cultures often involve contact with vectors of pathogenic spp. (e.g., consuming raw shellfish). High rates of mortality from certain spp. infections demonstrate the need for an improved understanding of spp. dynamics in estuarine regions. Our study assessed meteorological, hydrographic, and biological correlates of and at 10 sites in the Eastern Mississippi Sound System (EMSS) from April to October 2019. During the sampling period, median abundances of and were 2.31 log MPN/L and 2.90 log MPN/L, respectively. spp. dynamics were largely driven by site-based variation, with sites closest to freshwater inputs having the highest abundances. The E-W wind scalar, which affects Ekman transport, was a novel spp. correlate observed. A potential salinity effect on bacterial-particle associations was identified, where was associated with larger particles in conditions outside of their optimal salinity. Additionally, abundances were correlated to those of harmful algal species that did not dominate community chlorophyll. Correlates from this study may be used to inform the next iteration of regionally predictive models and may lend additional insight to spp. ecology in similar systems.
IMPORTANCE
spp. are bacteria found in estuaries worldwide; some species can cause illness and infections in humans. Relationships between spp. abundance, salinity, and temperature are well documented, but correlations to other environmental parameters are less understood. This study identifies unique correlates (e.g., E-W wind scalar and harmful algal species) that could potentially inform the next iteration of predictive models for the EMSS region. Additionally, these correlates may allow existing environmental monitoring efforts to be leveraged in providing data inputs for future Vibrio risk models. An observed correlation between salinity and /particle-size associations suggests that predicted environmental changes may affect the abundance of spp. in certain reservoirs, which may alter which vectors present the greatest vibrio risk.
Topics: Vibrio parahaemolyticus; Vibrio vulnificus; Estuaries; Alabama; Population Dynamics; Salinity; Vibrio Infections; Seawater; Water Microbiology
PubMed: 38578091
DOI: 10.1128/spectrum.03674-23 -
Gut Pathogens Nov 2023We report a 36-year-old male patient died of V. vulnificus-induced septicaemia and multiple organ failure syndrome after oyster consumption at a restaurant. We isolated...
We report a 36-year-old male patient died of V. vulnificus-induced septicaemia and multiple organ failure syndrome after oyster consumption at a restaurant. We isolated and identified V. vulnificus vv16015 from the patient's blood sample and antibiotic susceptibility tests indicated sensitivity to all 21 antibiotics. Oyster samples were subsequently collected from the restaurant's supplier and three strains of V. vulnificus were isolated. Whole genome sequencing and analysis revealed vv16015 to be distantly related to these strains and confirmed that V. vulnificus contamination was present in the seafood of the restaurant and supplier. Using a Galleria mellonella larvae infection model, the virulence of vv16015 was determined to be higher than that of comparison strains isolated from a surviving patient (vv15018) and an oyster (vv220015). The human and environment distribution of V. vulnificus in Shenzhen is sporadic and heterogeneous, and vv16015 is highly virulent compared to other strains.
PubMed: 38007445
DOI: 10.1186/s13099-023-00580-x -
Microorganisms Sep 2023This study aimed to determine the incidence and virulence factor profiling of species from hospital wastewater (HWW) and community wastewater effluents. Wastewater...
This study aimed to determine the incidence and virulence factor profiling of species from hospital wastewater (HWW) and community wastewater effluents. Wastewater samples from selected sites were collected, processed, and analysed presumptively by the culture dependent methods and molecular techniques. A total of 270 isolates were confirmed as genus delineating into (27%), (9.1%), (4.1%), and (3%). The remainder (>50%) may account for other species not identified in the study. The four species were isolated from secondary hospital wastewater effluent (SHWE), while was the sole specie isolated from Limbede community wastewater effluent (LCWE) and none of the four species was recovered from tertiary hospital wastewater effluent (THWE). However, several virulence genes were identified among isolates from SHWE: (88%), (81%), (64%), (58%), (44%), and (34%). Virulence genes factors among isolates from LCWE were: (78%), (67%), (44%), and (44%). Two different genes ( and ) were identified in all confirmed isolates. Among , (50%) and (67%) were detected. In , (56%) and (100%) were also identified. This finding reveals that the studied aquatic niches pose serious potential health risk with species harbouring virulence signatures. The distribution of virulence genes is valuable for ecological site quality, as well as epidemiological marker in the control and management of diseases caused by species. Regular monitoring of HWW and communal wastewater effluent would allow relevant establishments to forecast, detect, and mitigate any public health threats in advance.
PubMed: 37894107
DOI: 10.3390/microorganisms11102449 -
Frontiers in Microbiology 2023is a multi-host pathogenic species currently subdivided into five phylogenetic lineages (L) plus one pathovar with the ability to infect fish due to a transmissible...
is a multi-host pathogenic species currently subdivided into five phylogenetic lineages (L) plus one pathovar with the ability to infect fish due to a transmissible virulence plasmid. This plasmid (or a fragment of it) has been transmitted between lineages within the species, contributing to the evolution of . This study aimed to provide an experimental approximation to the mutation rate by determining spontaneous mutation rates from bacterial cultures of representants of the different lineages by whole-genome sequencing. To this purpose, synonymous SNP differences, i.e., spontaneous mutation not subjected to the evolutive forces, between initial and final culture after serial growth were evaluated and used for mutation rate calculation.
PubMed: 37621400
DOI: 10.3389/fmicb.2023.1223293