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Archives of Microbiology Oct 2022Glycogen is important for transmission of V. vulnificus undergoing disparate environments of nutrient-rich host and nutrient-limited marine environment. The malZ gene of...
Glycogen is important for transmission of V. vulnificus undergoing disparate environments of nutrient-rich host and nutrient-limited marine environment. The malZ gene of V. vulnificus encoding a maltodextrin glucosidase was cloned and over-expressed in E. coli to investigate its roles in glycogen/maltodextrin metabolism in the pathogen. The malZ gene encoded a protein with a predicted molecular mass of 70 kDa. The optimal pH and temperature of MalZ was 7.0 and 37 °C, respectively. MalZ hydrolyzed maltodextrin to glucose and maltose most efficiently, while hydrolyzed other substrates such as starch, maltose, β-cyclomaltodextrin, and glycogen less efficiently. The activity was enhanced greatly by Mn. It also exhibited transglycosylation activity toward excessive maltotriose. The malZ knock-out mutant accumulated 2.3-5.6-fold less glycogen than the wild type when excessive maltodextrin or glucose was added to LB medium, while it accumulated more glycogen than the wild type (3.5-fold) in the presence of excessive maltose. Growth and glycogen accumulation of the mutant were retarded most significantly in the M63 minimal medium supplemented with 0.5% maltodextrin. Side chain length distributions of glycogen molecules were varied by the malZ mutation and types of the excessive carbon source. Based on the results, MalZ of V. vulnificus was likely to be involved in maltose/maltodextrin metabolism, thereby balancing synthesis of glycogen and energy generation in the cell. The bacterium seemed to have multiple and unique pathways for glycogen metabolism according to carbon sources.
Topics: Carbon; Escherichia coli; Escherichia coli Proteins; Glucose; Glucosidases; Glycogen; Glycoside Hydrolases; Maltose; Polysaccharides; Starch; Vibrio vulnificus
PubMed: 36220932
DOI: 10.1007/s00203-022-03274-1 -
Frontiers in Microbiology 2022is known to cause necrotizing soft tissue infections (NSTIs). However, the pathogenic mechanism causing cellulitis, necrotizing fasciitis, muscle necrosis, and rapidly... (Review)
Review
is known to cause necrotizing soft tissue infections (NSTIs). However, the pathogenic mechanism causing cellulitis, necrotizing fasciitis, muscle necrosis, and rapidly developing septicemia in humans have not been fully elucidated. Here, we report a multilayer analysis of tissue damage after subcutaneous bacterial inoculation as a murine model of NSTIs. Our histopathological examination showed the progression of cellulitis, necrotizing fasciitis, and muscle necrosis worsening as the infection penetrated deeper into the muscle tissue layers. The increase in vascular permeability was the primary cause of the swelling and congestion, which are acute signs of inflammation in soft tissue and characteristic of human NSTIs. Most importantly, our sequential analysis revealed for the first time that not only spreads along the skin and subcutaneous tissues or fascia but also invades deeper muscle tissues beyond the fascia as the crucial process of its lethality. Also, increased vascular permeability enabled to proliferate in muscle tissue and enter the systemic circulation, escalating the bacterium's lethality. Our finding may yield important clinical benefits to patients by helping physicians understand the impact of surgical debridement on the patient's quality of life. Furthermore, this study provides a promising system to accelerate studies of virulence factors and eventually help establish new therapies.
PubMed: 35350614
DOI: 10.3389/fmicb.2022.849600 -
International Journal of Molecular... Jun 2022() infection-associated multiple antibiotic resistance has raised serious public health concerns. Recently, nanosponges (NSs) have been expected to provide innovative...
() infection-associated multiple antibiotic resistance has raised serious public health concerns. Recently, nanosponges (NSs) have been expected to provide innovative platforms for addressing antibacterial and drug-resistant challenges by targeting various pore-forming toxins (PFTs). In the present study, we constructed NSs to explore the effects and possible mechanism of recombinant hemolysin (rVvhA)-induced injuries. In vitro, NSs significantly reversed rVvhA-induced apoptosis and necrosis, and improved toxin-induced intracellular reactive oxygen species (ROS) production, adenosine triphosphate (ATP) depletion, and apoptosis signaling pathway disruption. To explore the clinical translation potential of NSs, we established VvhA-induced septicemia and wound infection mouse models, respectively, and further found NSs could notably attenuate rVvhA-induced acute toxicity and septicemia-associated inflammation, as well as local tissue damage. In a conclusion, NSs showed excellent protective effects against rVvhA-induced toxicity, thus providing useful insights into addressing the rising threats of severe infections.
Topics: Animals; Bacterial Proteins; Biomimetics; Hemolysin Proteins; Mice; Reactive Oxygen Species; Sepsis; Vibrio Infections; Vibrio vulnificus
PubMed: 35743264
DOI: 10.3390/ijms23126821 -
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 -
Frontiers in Microbiology 2021is an opportunistic pathogen indigenous to estuarine and marine environments and associated with aquatic organisms. is of utmost importance because it causes 95% of...
is an opportunistic pathogen indigenous to estuarine and marine environments and associated with aquatic organisms. is of utmost importance because it causes 95% of the seafood-related deaths in the United States due to rapid progression of septicemia. Changes in environmental parameters associated with climate change and coastal population expansion are altering geographical constraints, resulting in increased spread, exposure, and rates of infection. In addition, coastal population expansion is resulting in increased input of treated municipal sewage into areas that are also experiencing increased proliferation. This study aimed to better understand the influence of treated sewage effluent on effluent-receiving microbial communities using as a model of an opportunistic pathogen. Integrated transcriptomic approaches were used to analyze the changes in overall gene expression of NBRC 15645 exposed to wastewater treatment plant (WWTP) effluent for a period of 6h using a modified seawater yeast extract media that contained 0, 50, and 100% filtered WWTP effluent. RNA-seq reads were mapped, annotated, and analyzed to identify differentially expressed genes using the Pathosystems Resource Integration Center analysis tool. The study revealed that responds to wastewater effluent exposure by activating cyclic-di-GMP-influenced biofilm development. Also, genes involved in crucial functions, such as nitrogen metabolism and bacterial attachment, were upregulated depending on the presence of treated municipal sewage. This altered gene expression increased growth and proliferation and enhanced genes and pathways involved in bacterial survival during the early stages of infection in a host. These factors represent a potential public health risk due to exposure to environmental reservoirs of potentially strains with enhanced virulence profiles in coastal areas.
PubMed: 34759904
DOI: 10.3389/fmicb.2021.754683 -
Journal of Food Protection Nov 2020Vibrio parahaemolyticus and V. vulnificus are naturally occuring human pathogenic bacteria commonly found in estuarine environments where oysters are cultured. The use...
Vibrio parahaemolyticus and V. vulnificus are naturally occuring human pathogenic bacteria commonly found in estuarine environments where oysters are cultured. The use of triploid oysters has increased, due to their rapid growth rate and that they maintain a high quality throughout the year. Previous work suggested levels of Vibrio spp. may be lower in triploid oysters, as compared to diploids. Therfore, this study aimed to determine if there is a difference in the abundances of V. parahaemolyticus and V. vulnificus between half-sibling diploid and triploid oysters. In four trials, 100 individual oysters (either iced or temperature abused) were analyzed for V. parahaemolyticus and V. vulnificus using direct plating followed by colony hybridization. Mean levels of V. parahaemolyticus in iced and abused diploid oysters were 3.55 and 4.21 log CFU/g, respectively. Mean levels in iced and abused triploid oysters were 3.49 and 4.27 log CFU/g, respectively. Mean levels of V. vulnificus in iced and abused diploid oysters were 3.53 and 4.56 log CFU/g, respectively. Mean levels in iced and abused triploid oysters were 3.54 and 4.55 log CFU/g, respectively. The differences in Vibrio spp. abundances between diploid and triploid oysters was not significant (p>0.05). However, the differences across treatments were significant (p<0.05), with the exception of V. parahaemolyticus levels in trial 3 (p=0.83). Variation between individual oysters was also observed, with 12 of 808 measurements being outside of the 95 th percentile. This phenomenon of occasional statistical outliers ("hot" or "cold" oysters) has been previously described and supports the appropriateness of composite sampling to account for inherent animal variability. In summary, the data indicate that abundances of V. parahaemolyticus and V. vulnificus are not dependent on the ploidy of cultured oysters, but vary with the type of handling.
PubMed: 32649752
DOI: 10.4315/JFP-20-202 -
Frontiers in Microbiology 2021is an important pathogenic bacterium that is often associated with seafood-borne illnesses. Therefore, to detect this pathogen in aquatic products, a DNAzyme-based...
is an important pathogenic bacterium that is often associated with seafood-borne illnesses. Therefore, to detect this pathogen in aquatic products, a DNAzyme-based fluorescent sensor was developed for the detection of . After screening and mutation, a DNAzyme that we denominated "RFD-VV-M2" exhibited the highest activity, specificity, and sensitivity. The limit of detection was 2.2 × 10 CFU/ml, and results could be obtained within 5-10 min. Our findings suggested that the target of DNAzyme RFD-VV-M2 was a protein with a molecular weight between 50 and 100 kDa. The proposed biosensor exhibited an excellent capacity to detect marine products contaminated with . Therefore, our study established a rapid, simple, sensitive, and highly specific detection method for in aquatic products.
PubMed: 34149642
DOI: 10.3389/fmicb.2021.655845 -
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 -
Research in Microbiology 2023New drugs are urgently required for the treatment of infections due to an increasing number of new strains of diseases-causing pathogens and antibiotic-resistant...
New drugs are urgently required for the treatment of infections due to an increasing number of new strains of diseases-causing pathogens and antibiotic-resistant bacteria. A library of drugs approved by Food and Drug Administration was screened for efficacy against Vibrio vulnificus using antimicrobial assays. We found that otilonium bromide showed potent antimicrobial activity against V.vulnificus and had a synergistic effect in combination with antibiotics. Field emission transmission electron microscope images revealed that otilonium bromide caused cell division defects in V.vulnificus. Moreover, it significantly inhibited V.vulnificus swarming motility and adhesion to host cells at concentrations lower than the minimum inhibitory concentration. To investigate its inhibitory action mechanisms, we examined the effect of otilonium bromide on the expression levels of several proteins crucial for V.vulnificus growth, motility, and adhesion. It decreased the protein expression levels of cAMP receptor protein and flagellin B, but not HlyU or OmpU. In addition, otilonium bromide significantly decreased the expression levels of outer membrane protein TolCV1, thus inhibiting RtxA1 toxin secretion and substantially reducing V.vulnificus cytotoxicity to host cells. Collectively, these findings suggest that otilonium bromide may be considered as a promising candidate for treating V.vulnificus infections.
Topics: Humans; Vibrio vulnificus; Anti-Bacterial Agents; Quaternary Ammonium Compounds; Microbial Sensitivity Tests; Vibrio Infections
PubMed: 36122890
DOI: 10.1016/j.resmic.2022.103992 -
Frontiers in Microbiology 2022is an invasive marine bacterium that causes a variety of serious infectious diseases. With the increasing multidrug-resistant variants, treatment of . infections is...
is an invasive marine bacterium that causes a variety of serious infectious diseases. With the increasing multidrug-resistant variants, treatment of . infections is becoming more difficult. In this study, we explored antimicrobial blue light (aBL; 405 nm wavelength) for the treatment of infections. We first assessed the efficacy of aBL against five strains of . Next, we identified and quantified intracellular porphyrins in to provide mechanistic insights. Additionally, we measured intracellular reactive oxygen species (ROS) production and bacterial membrane permeabilization following aBL exposures. Lastly, we conducted a preclinical study to investigate the efficacy and safety of aBL for the prevention and treatment of burn infections caused by in mice. We found that aBL effectively killed in both planktonic and biofilm states, with up to a 5.17- and 4.57-log CFU reduction being achieved, respectively, following an aBL exposure of 216 J/cm. Protoporphyrin IX and coproporphyrins were predominant in all the strains. Additionally, intracellular ROS was significantly increased following aBL exposures ( < 0.01), and there was evidence of aBL-induced permeabilization of the bacterial membrane ( < 0.0001). In the preclinical studies, we found that female mice treated with aBL 30 min after bacterial inoculation showed a survival rate of 81% following 7 days of observation, while only 28% survival was observed in untreated female mice ( < 0.001). At 6 h post-inoculation, an 86% survival was achieved in aBL-treated female mice ( = 0.0002). For male mice, 86 and 63% survival rates were achieved when aBL treatment was given 30 min and 6 h after bacterial inoculation, respectively, compared to 32% survival in the untreated mice ( = 0.0004 and = 0.04). aBL did not reduce cellular proliferation or induce apoptosis. We found five cytokines were significantly upregulated in the males after aBL treatment, including MCSF ( < 0.001), MCP-5 ( < 0.01), TNF RII ( < 0.01), CXCL1 ( < 0.01), and TIMP-1 ( < 0.05), and one in the females (TIMP-1; < 0.05), suggesting that aBL may induce certain inflammatory processes. In conclusion, aBL may potentially be applied to prevent and treat infections.
PubMed: 35903474
DOI: 10.3389/fmicb.2022.932466