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BioRxiv : the Preprint Server For... May 2023causes life threatening infections dependent upon the effectors released from the Multifunctional-Autoprocessing Repeats-In-Toxin (MARTX) toxin. The Makes Caterpillars...
causes life threatening infections dependent upon the effectors released from the Multifunctional-Autoprocessing Repeats-In-Toxin (MARTX) toxin. The Makes Caterpillars Floppy-like (MCF) cysteine protease effector is activated by host ADP ribosylation factors (ARFs), although the targets of processing activity were unknown. In this study we show MCF binds Ras-related proteins in brain (Rab) GTPases at the same interface occupied by ARFs and then cleaves and/or degrades 24 distinct members of the Rab GTPases family. The cleavage occurs in the C-terminal tails of Rabs. We determine the crystal structure of MCF as a swapped dimer revealing the open, activated state of MCF and then use structure prediction algorithms to show that structural composition, rather than sequence or localization, determine Rabs selected as MCF proteolytic targets. Once cleaved, Rabs become dispersed in cells to drive organelle damage and cell death to promote pathogenesis of these rapidly fatal infections.
PubMed: 37131655
DOI: 10.1101/2023.04.19.537381 -
Viruses Mar 2023Oncolytic viral therapy is a promising novel approach to cancer treatment. Oncolytic viruses cause tumor regression through direct cytolysis on the one hand and...
Oncolytic viral therapy is a promising novel approach to cancer treatment. Oncolytic viruses cause tumor regression through direct cytolysis on the one hand and recruiting and activating immune cells on the other. In this study, to enhance the antitumor efficacy of the thymidine kinase-deficient vaccinia virus (VV, Lister strain), recombinant variants encoding bacterial flagellin (subunit B) of (LIVP-FlaB-RFP), firefly luciferase (LIVP-Fluc-RFP) or red fluorescent protein (LIVP-RFP) were developed. The LIVP-FLuc-RFP strain demonstrated exceptional onco-specificity in tumor-bearing mice, detected by the in vivo imaging system (IVIS). The antitumor efficacy of these variants was explored in syngeneic murine tumor models (B16 melanoma, CT26 colon cancer and 4T1 breast cancer). After intravenous treatment with LIVP-FlaB-RFP or LIVP-RFP, all mice tumor models exhibited tumor regression, with a prolonged survival rate in comparison with the control mice. However, superior oncolytic activity was observed in the B16 melanoma models treated with LIVP-FlaB-RFP. Tumor-infiltrated lymphocytes and the cytokine analysis of the serum and tumor samples from the melanoma-xenografted mice treated with these virus variants demonstrated activation of the host's immune response. Thus, the expression of bacterial flagellin by VV can enhance its oncolytic efficacy against immunosuppressive solid tumors.
Topics: Animals; Mice; Vaccinia virus; Flagellin; Melanoma, Experimental; Oncolytic Viruses; Oncolytic Virotherapy; Cell Line, Tumor
PubMed: 37112810
DOI: 10.3390/v15040828 -
International Journal of Environmental... Apr 2023Over the last two decades, infections have emerged as an increasingly serious public health threat along the German Baltic coast. To manage related risks, near...
Over the last two decades, infections have emerged as an increasingly serious public health threat along the German Baltic coast. To manage related risks, near real-time (NRT) modelling of quantities has often been proposed. Such models require spatially explicit input data, for example, from remote sensing or numerical model products. We tested if data from a hydrodynamic, a meteorological, and a biogeochemical model are suitable as input for an NRT model system by coupling it with field samples and assessing the models' ability to capture known ecological parameters of . We also identify the most important predictors for in the Baltic Sea by leveraging the St. Nicolas House Analysis. Using a 27-year time series of sea surface temperature, we have investigated trends of season length, which pinpoint hotspots mainly in the east of our study region. Our results underline the importance of water temperature and salinity on abundance but also highlight the potential of air temperature, oxygen, and precipitation to serve as predictors in a statistical model, albeit their relationship with may not be causal. The evaluated models cannot be used in an NRT model system due to data availability constraints, but promising alternatives are presented. The results provide a valuable basis for a future NRT model for in the Baltic Sea.
Topics: Humans; Vibrio vulnificus; Vibrio Infections; Water; Baltic States; Oxygen
PubMed: 37107825
DOI: 10.3390/ijerph20085543 -
GeoHealth Apr 2023Climate-induced stressors, such as changes in temperature, salinity, and pH, contribute to the emergence of infectious diseases. These changes alter geographical...
Climate-induced stressors, such as changes in temperature, salinity, and pH, contribute to the emergence of infectious diseases. These changes alter geographical constraint, resulting in increased spread, exposure, and infection rates, thus facilitating greater -human interactions. Multiple efforts have been developed to predict exposure and raise awareness of health risks, but most models only use temperature and salinity as prediction factors. This study aimed to better understand the potential effects of temperature and pH on and planktonic and biofilm growth. strains were grown in triplicate at 25°, 30°, and 37°C in 96 well plates containing Modified Seawater Yeast Extract modified with CaCl at pH's ranging from 5 to 9.6. AMiGA software was used to model growth curves using Gaussian process regression. The effects of temperature and pH were evaluated using randomized complete block analysis of variance, and the growth rates of and were modeled using the interpolation fit on the MatLab Curve Fitting Toolbox. Different optimal conditions involving temperature and pH were observed for planktonic and biofilm growth within- and between-species. This study showed that temperature and pH factors significantly affect planktonic growth rates and biofilm formation. Therefore, pH effects must be added to the growth modeling efforts to better predict risk in estuarine and coastal zones that can potentially experience the cooccurrence of and harmful algal bloom outbreak events.
PubMed: 37091291
DOI: 10.1029/2022GH000769 -
Italian Journal of Food Safety Mar 2023The genus includes bacteria with different morphological and metabolic characteristics responsible for different human and animal diseases. An accurate identification...
The genus includes bacteria with different morphological and metabolic characteristics responsible for different human and animal diseases. An accurate identification is essential to assess the risks in regard to aquatic organisms and consequently to public health. The Multilocus Sequence Analysis (MLSA) scheme developed on the basis of 4 housekeeping genes (B, H, A and A) was applied to identify 92 strains isolated from crustaceans in 2011. Concatenated sequences were used for the phylogenetic and population analyses and the results were compared with those from biochemical identification tests. From the phylogenetic analysis, 10 clusters and 4 singletons emerged, whereas the population analysis highlighted 12 subpopulations that were well supported by phylogeny with few exceptions. The retrospective analysis allowed correct re-attribution of isolated species, indicating how, for some pathogens, there may be an overestimation of phenotypic identification (. ). Use of the PubMLST database highlighted a possible genetic link between Sequence Type (ST) 529 and ST195 () isolated from a human case in Norway during 2018. In addition to the identification of major risk groups of , and , MLSA could be a valid support for species considered a minor risk, such as , and . Due to the increased incidence of vibriosis in Europe, the application of different tools will also have to be considered to investigate the possible epidemiological links of the various species in the perspective of to protect the consumer.
PubMed: 37064522
DOI: 10.4081/ijfs.2023.11045 -
Journal of Food Protection Jun 2023Vibrio parahaemolyticus illnesses, often associated with the consumption of raw or undercooked oysters, are most common in summer months when higher temperatures...
Vibrio parahaemolyticus illnesses, often associated with the consumption of raw or undercooked oysters, are most common in summer months when higher temperatures increase V. parahaemolyticus levels in the environment. In Washington, post-harvest controls focus on the time from harvest to temperature-controlled storage to minimize V. parahaemolyticus illness risk. This study examined the effect of post-harvest ambient storage on V. parahaemolyticus levels in Pacific oysters. Additionally, the effects of cooling method, icing and/or refrigeration, on V. parahaemolyticus levels in oysters were evaluated. Five independent trials were conducted during July and August of 2015. For each trial, oysters were harvested from Totten Inlet and exposed to ambient conditions for 0 h (immediately cooled), 1 h, 5 h, or 9 h, and then either iced or refrigerated. Total and pathogenic (tdh+/trh+) V. parahaemolyticus levels were determined via MPN real-time PCR. Data from each trial were analyzed independently due to differences in initial V. parahaemolyticus levels. Total V. parahaemolyticus levels in oysters increased relative to control (0 h I) levels after the 1 h ambient exposure in only one trial, but pathogenic V. parahaemolyticus levels did not significantly increase after the 1 h exposure. Total and pathogenic V. parahaemolyticus levels increased by 0.8-1.9 log MPN/g in 5 h exposed oysters and by 1.0-2.9 log MPN/g in 9 h exposed oysters compared to levels in 0 h I samples. Mean maximum temperature of 5 h and 9 h exposed samples increased to ≈29°C compared to ≈21°C in 0 h and 1 h exposures, which likely contributed to observed increases in V. parahaemolyticus levels. Total and pathogenic V. parahaemolyticus levels increased more often in oysters cooled by refrigeration than by ice; this was most notable for the longer ambient exposure samples. Overall, these data support shorter post-harvest ambient exposure as well as rapid cooling of oysters to minimize risk of V. parahaemolyticus illness.
Topics: Animals; Crassostrea; Vibrio parahaemolyticus; Washington; Food Contamination; Ostreidae; Cold Temperature; Vibrio vulnificus; Colony Count, Microbial
PubMed: 37061186
DOI: 10.1016/j.jfp.2023.100092 -
International Journal of Infectious... Jul 2023The aim of this study was to investigate the prognostic value of reclassified new type III monomicrobial gram-negative necrotizing fasciitis (NF) and the microbial...
High mortality risk of type III monomicrobial gram-negative necrotizing fasciitis: The role of extraintestinal pathogenic Escherichia coli (ExPEC) and Klebsiella pneumoniae.
OBJECTIVES
The aim of this study was to investigate the prognostic value of reclassified new type III monomicrobial gram-negative necrotizing fasciitis (NF) and the microbial factors associated with an increased risk of mortality.
METHODS
This study included 235 NF cases treated at National Taiwan University Hospital. We compared the mortality risk of NF caused by different causal microorganisms and examined the bacterial virulence genes profile and antimicrobial susceptibility pattern associated with an increase in mortality risk.
RESULTS
Type III NF (n = 68) had a mortality risk two-fold higher than type I (polymicrobial, n = 64) or type II (monomicrobial gram-positive, n = 79) NF (42.6% vs 23.4% or 19.0%, P = 0.019 and 0.002, respectively). Mortality differed by causal microorganism (Escherichia coli [61.5%], Klebsiella pneumoniae [40.0%], Aeromonas hydrophila [37.5%], Vibrio vulnificus [25.0%], polymicrobial [23.4%], group A streptococci [16.7%], and Staphylococcus aureus [16.2%], in decreasing rank, P <0.001). Type III NF caused by E. coli, identified as extraintestinal pathogenic E. coli (ExPEC) via virulence gene analyses, was associated with a particularly high mortality risk (adjusted odds ratio: 6.51, P = 0.003) after adjusting for age and comorbidities. Some (38.5%/7.7%) of the E. coli strains were non-susceptible to third/fourth-generation cephalosporins but remained susceptible to carbapenems.
CONCLUSION
Type III NF, especially cases caused by E. coli or K. pneumoniae, are associated with a comparatively higher mortality risk than type I or type II NF. Wound gram stain-based rapid diagnosis of type III NF may inform empirical antimicrobial therapy to include a carbapenem.
Topics: Humans; Fasciitis, Necrotizing; Klebsiella pneumoniae; Escherichia coli; Extraintestinal Pathogenic Escherichia coli; Streptococcal Infections; Carbapenems; Anti-Bacterial Agents; Escherichia coli Infections
PubMed: 37059297
DOI: 10.1016/j.ijid.2023.04.390 -
International Journal of Molecular... Apr 2023Bacterial nitroreductase enzymes that convert prodrugs to cytotoxins are valuable tools for creating transgenic targeted ablation models to study cellular function and...
Bacterial nitroreductase enzymes that convert prodrugs to cytotoxins are valuable tools for creating transgenic targeted ablation models to study cellular function and cell-specific regeneration paradigms. We recently engineered a nitroreductase ("NTR 2.0") for substantially enhanced reduction of the prodrug metronidazole, which permits faster cell ablation kinetics, cleaner interrogations of cell function, ablation of previously recalcitrant cell types, and extended ablation paradigms useful for modelling chronic diseases. To provide insight into the enhanced enzymatic mechanism of NTR 2.0, we have solved the X-ray crystal structure at 1.85 Angstroms resolution and compared it to the parental enzyme, NfsB from . We additionally present a survey of reductive activity with eight alternative nitroaromatic substrates, to provide access to alternative ablation prodrugs, and explore applications such as remediation of dinitrotoluene pollutants. The predicted binding modes of four key substrates were investigated using molecular modelling.
Topics: Animals; Substrate Specificity; Prodrugs; Metronidazole; Animals, Genetically Modified; Nitroreductases
PubMed: 37047605
DOI: 10.3390/ijms24076633 -
Scientific Reports Mar 2023Vibrio vulnificus is an opportunistic bacterial pathogen, occurring in warm low-salinity waters. V. vulnificus wound infections due to seawater exposure are infrequent...
Vibrio vulnificus is an opportunistic bacterial pathogen, occurring in warm low-salinity waters. V. vulnificus wound infections due to seawater exposure are infrequent but mortality rates are high (~ 18%). Seawater bacterial concentrations are increasing but changing disease pattern assessments or climate change projections are rare. Here, using a 30-year database of V. vulnificus cases for the Eastern USA, changing disease distribution was assessed. An ecological niche model was developed, trained and validated to identify links to oceanographic and climate data. This model was used to predict future disease distribution using data simulated by seven Global Climate Models (GCMs) which belong to the newest Coupled Model Intercomparison Project (CMIP6). Risk was estimated by calculating the total population within 200 km of the disease distribution. Predictions were generated for different "pathways" of global socioeconomic development which incorporate projections of greenhouse gas emissions and demographic change. In Eastern USA between 1988 and 2018, V. vulnificus wound infections increased eightfold (10-80 cases p.a.) and the northern case limit shifted northwards 48 km p.a. By 2041-2060, V. vulnificus infections may expand their current range to encompass major population centres around New York (40.7°N). Combined with a growing and increasingly elderly population, annual case numbers may double. By 2081-2100 V. vulnificus infections may be present in every Eastern USA State under medium-to-high future emissions and warming. The projected expansion of V. vulnificus wound infections stresses the need for increased individual and public health awareness in these areas.
Topics: Humans; Aged; Vibrio vulnificus; Vibrio Infections; North America; Wound Infection
PubMed: 36959189
DOI: 10.1038/s41598-023-28247-2 -
MSystems Apr 2023Vibrio vulnificus is a bacterium that inhabits warm seawater or brackish water environments and causes foodborne diseases and wound infections. In severe cases, V....
Vibrio vulnificus is a bacterium that inhabits warm seawater or brackish water environments and causes foodborne diseases and wound infections. In severe cases, V. vulnificus invades the skeletal muscle tissue, where bacterial proliferation leads to septicemia and necrotizing fasciitis with high mortality. Despite this characteristic, information on metabolic changes in tissue infected with V. vulnificus is not available. Here, we elucidated the metabolic changes in V. vulnificus-infected mouse skeletal muscle using capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS). Metabolome analysis revealed changes in muscle catabolites and energy metabolites during V. vulnificus infection. In particular, succinic acid accumulated but fumaric acid decreased in the infected muscle. However, the virulence factor deletion mutant revealed that changes in metabolites and bacterial proliferation were abolished in skeletal muscle infected with a multifunctional-autoprocessing repeats-in-toxin (MARTX) mutant. On the other hand, mice that were immunosuppressed via cyclophosphamide (CPA) treatment exhibited a similar level of bacterial counts and metabolites between the wild type and MARTX mutant. Therefore, our data indicate that V. vulnificus induces metabolic changes in mouse skeletal muscle and proliferates by using the MARTX toxin to evade the host immune system. This study indicates a new correlation between V. vulnificus infections and metabolic changes that lead to severe reactions or damage to host skeletal muscle. V. vulnificus causes necrotizing skin and soft tissue infections (NSSTIs) in severe cases, with high mortality and sign of rapid deterioration. Despite the severity of the infection, the dysfunction of the host metabolism in skeletal muscle triggered by V. vulnificus is poorly understood. In this study, by using a mouse wound infection model, we revealed characteristic changes in muscle catabolism and energy metabolism in skeletal muscle associated with bacterial proliferation in the infected tissues. Understanding such metabolic changes in V. vulnificus-infected tissue may provide crucial information to identify the mechanism via which V. vulnificus induces severe infections. Moreover, our metabolite data may be useful for the recognition, identification, or detection of V. vulnificus infections in clinical studies.
Topics: Humans; Bacterial Toxins; Vibrio Infections; Virulence Factors; Muscle, Skeletal
PubMed: 36939368
DOI: 10.1128/msystems.00682-22