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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 Microbiology 2023is a gram-negative, opportunistic pathogen common to warm waters worldwide. Human infection is rare and typically affects those residing in coastal areas during the...
BACKGROUND
is a gram-negative, opportunistic pathogen common to warm waters worldwide. Human infection is rare and typically affects those residing in coastal areas during the summer months, but it causes rapid deterioration and is fatal.
METHODS
The medical records of six patients with sepsis caused by infection who were treated at the First Affiliated Hospital of Ningbo University from 2020 to 2022 were retrospectively reviewed. The patient demographics, clinical symptoms, laboratory test results, treatments, and outcomes are summarized.
RESULTS
infection was confirmed by blood or pus culture, 16S ribosomal DNA sequencing, and metagenomic next-generation sequencing. All six patients were male with pre-existing liver diseases and two reported consuming seafood before the onset of symptoms. Of the six patients, four succumbed to the disease, two recovered, and one underwent leg amputation.
CONCLUSION
infection progresses rapidly and is highly fatal, thus prompt and aggressive treatment is necessary. infection should be considered in older (>40 years) patients with a history of liver disease and recent consumption of seafood or exposure to seawater, especially those residing in coastal areas during the summer months.
PubMed: 37469427
DOI: 10.3389/fmicb.2023.1220526 -
Nucleic Acids Research Aug 2023Cell-free protein synthesis assays have become a valuable tool to understand transcriptional and translational processes. Here, we established a fluorescence-based...
Cell-free protein synthesis assays have become a valuable tool to understand transcriptional and translational processes. Here, we established a fluorescence-based coupled in vitro transcription-translation assay as a read-out system to simultaneously quantify mRNA and protein levels. We utilized the well-established quantification of the expression of shifted green fluorescent protein (sGFP) as a read-out of protein levels. In addition, we determined mRNA quantities using a fluorogenic Mango-(IV) RNA aptamer that becomes fluorescent upon binding to the fluorophore thiazole orange (TO). We utilized a Mango-(IV) RNA aptamer system comprising four subsequent Mango-(IV) RNA aptamer elements with improved sensitivity by building Mango arrays. The design of this reporter assay resulted in a sensitive read-out with a high signal-to-noise ratio, allowing us to monitor transcription and translation time courses in cell-free assays with continuous monitoring of fluorescence changes as well as snapshots of the reaction. Furthermore, we applied this dual read-out assay to investigate the function of thiamine-sensing riboswitches thiM and thiC from Escherichia coli and the adenine-sensing riboswitch ASW from Vibrio vulnificus and pbuE from Bacillus subtilis, which represent transcriptional and translational on- and off-riboswitches, respectively. This approach enabled a microplate-based application, a valuable addition to the toolbox for high-throughput screening of riboswitch function.
Topics: Adenine; Aptamers, Nucleotide; Fluorescence; Green Fluorescent Proteins; Nucleic Acid Conformation; Riboswitch; Cell-Free System
PubMed: 37409574
DOI: 10.1093/nar/gkad574 -
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 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 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 -
Access Microbiology 2023The stressosome is a protein complex that senses environmental stresses and mediates the stress response in several Gram-positive bacteria through the activation of the...
The stressosome is a protein complex that senses environmental stresses and mediates the stress response in several Gram-positive bacteria through the activation of the alternative sigma factor SigB. The stressosome locus is found in 44 % of Gram-negative isolates. However, does not possess SigB. Nonetheless, in nutrient-limited media, the stressosome modulates gene transcription and bacterial behaviour. In this work, the expression of the stressosome genes was proven during stationary phase in nutrient-rich media and co-transcription as one operonic unit of the stressosome locus and its putative downstream regulatory locus was demonstrated. The construction of a stressosome mutant lacking the genes encoding the four proteins constituting the stressosome complex (VvRsbR, VvRsbS, VvRsbT, VvRsbX) allowed us to examine the role of this complex . Extensive phenotypic characterization of the ΔRSTX mutant in nutrient-rich media showed that the stressosome does not contribute to growth of . Moreover, the stressosome did not modulate the tolerance or survival response of to the range of stresses tested, which included ethanol, hyperosmolarity, hypoxia, high temperature, acidity and oxidative stress. Furthermore, the stressosome was dispensable for motility and exoenzyme production of in nutrient-rich media. Therefore, in conclusion, although stressosome gene transcription occurs in nutrient-rich media, the stressosome neither has an essential role in stress responses of nor does it seem to modulate these activities in these conditions. We hypothesise that the stressosome is expressed in nutrient-rich conditions as a sensor complex, but that activation of the complex does not occur in this environment.
PubMed: 37601438
DOI: 10.1099/acmi.0.000523.v4 -
Frontiers in Cellular and Infection... 2023To evaluate the diagnostic value of metagenomic next-generation sequencing (mNGS) in () infection.
OBJECTIVE
To evaluate the diagnostic value of metagenomic next-generation sequencing (mNGS) in () infection.
METHODS
A retrospective analysis of patients with infection at the Fifth Affiliated Hospital of Sun Yat-Sen University from January 1, 2020 to April 23, 2023 was conducted. 14 enrolled patients were diagnosed by culture or mNGS. The corresponding medical records were reviewed, and the clinical data analyzed included demographics, epidemiology laboratory findings, physical examination, symptoms at presentation, antibiotic and surgical treatment, and outcome.
RESULTS
In this study, 78.6% (11/14) patients had a history of marine trauma (including fish stab, shrimp stab, crab splints and fish hook wounds), 7.1% (1/14) had eaten seafood, and the remaining 14.3% (2/14) had no definite cause. Isolation of from clinical samples including blood, tissue, fester and secreta. 9 cases were positive for culture, 5 cases were detected synchronously by mNGS and got positive for . 85.7% (12/14) cases accepted surgical treatment, with 1 patient suffering finger amputated. 14 enrolled patients received appropriate antibiotic therapy, and all of them had recovered and discharged. 9 strains isolated in this study were sensitive to most beta-lactam antibiotics, aminoglycosides, quinolones, etc.
CONCLUSION
infection is a common water-exposed disease in Zhuhai, which requires identification of a number of pathogens. Of severe infections with unknown pathogen, mNGS can be used simultaneously, and the potential to detect multiple pathogens is of great help in guiding treatment.
Topics: Animals; Humans; Retrospective Studies; Vibrio Infections; Vibrio vulnificus; Anti-Bacterial Agents; High-Throughput Nucleotide Sequencing
PubMed: 38035326
DOI: 10.3389/fcimb.2023.1210919 -
The Journal of Medical Investigation :... 2024Vibrio vulnificus (V. vulnificus) is a halophilic gram-negative bacterium that inhabits coastal warm water and induce severe diseases such as primary septicemia. To...
Vibrio vulnificus (V. vulnificus) is a halophilic gram-negative bacterium that inhabits coastal warm water and induce severe diseases such as primary septicemia. To investigate the mechanisms of rapid bacterial translocation on intestinal infection, we focused on outer membrane vesicles (OMVs), which are extracellular vesicles produced by Gram-negative bacteria and deliver virulence factors. However, there are very few studies on the pathogenicity or contents of V. vulnificus OMVs (Vv-OMVs). In this study, we investigated the effects of Vv-OMVs on host cells. Epithelial cells INT407 were stimulated with purified OMVs and morphological alterations and levels of lactate dehydrogenase (LDH) release were observed. In cells treated with OMVs, cell detachment without LDH release was observed, which exhibited different characteristics from cytotoxic cell detachment observed in V. vulnificus infection. Interestingly, OMVs from a Vibrio Vulnificus Hemolysin (VVH) and Multifunctional-autoprocessing repeats-in -toxin (MARTX) double-deletion mutant strain also caused cell detachment without LDH release. Our results suggested that the proteolytic function of a serine protease contained in Vv-OMVs may contribute to pathogenicity of V. vulnificus by assisting bacterial translocation. This study reveals a new pathogenic mechanism during V. vulnificus infections. J. Med. Invest. 71 : 102-112, February, 2024.
Topics: Vibrio vulnificus; Humans; Extracellular Vesicles; Hemolysin Proteins; L-Lactate Dehydrogenase; Bacterial Outer Membrane; Epithelial Cells
PubMed: 38735705
DOI: 10.2152/jmi.71.102 -
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