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Biochemistry and Biophysics Reports Sep 2022V. fluvialis is an emerging foodborne pathogen and could cause cholera-like gastroenteritis syndrome and poses a potential threat to public health. VflT6SS2 is a...
V. fluvialis is an emerging foodborne pathogen and could cause cholera-like gastroenteritis syndrome and poses a potential threat to public health. VflT6SS2 is a functionally active type VI secretion system (T6SS) in which confers bactericidal activity. VflT6SS2 is composed of one major cluster and three - orphan clusters. Previously, we identified two quorum sensing (QS) systems CqsA/LuxS-HapR and VfqI-VfqR in and demonstrated that the former regulates VflT6SS2. However, whether VfqI-VfqR QS regulates VflT6SS2 is unknown. In this study, we showed that the mRNA abundances of VflT6SS2 2 (), 2 () and 2 () were all significantly decreased in VfqI or/and VfqR deletion mutant(s). Consistently, Hcp expression/secretion was reduced too in these mutants. Complementation assay with VfqR mutant further confirmed that the reduced Hcp expression/secretion and impaired antibacterial virulence are restored by introducing VfqR-expressing plasmid. Reporter fusion analyses revealed that VfqR modulates the promoter activities of VflT6SS2. Bioinformatical prediction and further reporter fusion assay in supported that VfqR acts as a transcriptional factor to bind and regulate the gene expression of the VflT6SS2 major cluster. However, VfqR seems to promote transcription of (2) in the orphan clusters through elevating the expression of which is encoded by the VflT6SS2 major cluster. Additionally, we found that the regulation intensity of VfqR on VflT6SS2 is weaker than that of HapR. In conclusion, our current study disclosed that in , VfqI-VfqR circuit upregulates the expression and function of VflT6SS2 by directly or indirectly activating its transcription. These findings will enhance our understanding of the complicated regulatory network between QS and T6SS in .
PubMed: 35669988
DOI: 10.1016/j.bbrep.2022.101282 -
IScience May 2024is an emerging foodborne pathogen that produces VFH ( hemolysin) and δVFH (delta- hemolysin). The function of δVFH is unclear. Currently, no pathogenic . from deep...
is an emerging foodborne pathogen that produces VFH ( hemolysin) and δVFH (delta- hemolysin). The function of δVFH is unclear. Currently, no pathogenic . from deep sea has been reported. In this work, a deep-sea . isolate (V13) was examined for pathogenicity. V13 was most closely related to ATCC 33809, a human isolate, but possessed 262 unique genes. V13 caused lethal infection in fish and induced pyroptosis involving activation of the NLRP3 inflammasome, caspase 1 (Casp1), and gasdermin D (GSDMD). V13 defective in VFH or VFH plus δVFH exhibited significantly weakened cytotoxicity. Recombinant δVFH induced NLRP3-Casp1-GSDMD-mediated pyroptosis in a manner that depended on K efflux and intracellular Ca accumulation. δVFH bound several plasma membrane lipids, and these bindings were crucial for δVFH cytotoxicity. Together these results provided new insights into the function of δVFH and the virulence mechanism of .
PubMed: 38650982
DOI: 10.1016/j.isci.2024.109558 -
Journal of Tropical Medicine 2023The noncholera spp. which cause vibriosis are abundantly found in our water ecosystem. These bacteria could negatively affect both humans and animals. To date, there is...
BACKGROUND
The noncholera spp. which cause vibriosis are abundantly found in our water ecosystem. These bacteria could negatively affect both humans and animals. To date, there is a paucity of information available on the existence and pathogenicity of this particular noncholera spp. in Malaysia in comparison to their counterpart, .
METHODS
In this study, we extracted retrospective data from Malaysian surveillance database. Analysis was carried out using WHONET software focusing noncholera spp. including , , , , (), , , and .
RESULTS
Here, we report the first distribution and prevalence of these species isolated in Malaysia together with the antibiotic sensitivity profile based on the species. We found that is the predominant species isolated in Malaysia. Noticeably, across the study period, is becoming more prevalent, as compared to . In addition, this study also reports the first isolation of pathogenic from stool in Malaysia.
CONCLUSION
These data represent an important step toward understanding the potential emergence of noncholera spp. outbreaks.
PubMed: 37274080
DOI: 10.1155/2023/2716789 -
Applied and Environmental Microbiology Feb 2019Inappropriate and disproportionate use of antibiotics is contributing immensely to the development of antibiotic resistance in bacterial species associated with food...
Inappropriate and disproportionate use of antibiotics is contributing immensely to the development of antibiotic resistance in bacterial species associated with food contamination. The use of natural products in combination can be a potent alternative hurdle strategy to inactivate foodborne pathogens. Here, we explored the pro-oxidant properties of essential oil inalool and itamin C in combination with opper (LVC) in combating the foodborne pathogens and subsp. serovar Typhi using a three-dimensional (3D) checkerboard microdilution assay. Antibacterial activity in terms of the MIC revealed that the triple combination exerted a synergistic effect compared to the effects of the individual constituents. The bactericidal effect of the triple combination was confirmed by a live/dead staining assay. Reactive oxygen species (ROS) measurements with the terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling assay and scanning electron microscopy imaging strongly suggested that the increase in ROS production is the underlying mechanism of the enhanced antibacterial potency of the LVC combination (linalool [1.298 mM], vitamin C [8 mM], copper [16.3 μM]). In addition, the hypersensitivity of oxidative stress regulator mutants (, , , and mutants) toward LVC corroborated the involvement of ROS in cell death. Live/dead staining and changes in cellular morphology revealed that oxidative stress did not transform the cells into the viable but nonculturable (VBNC) state; rather, killing was associated with intracellular and extracellular oxidative burst. Furthermore, the LVC combination did not display toxicity to human cells, while it effectively reduced the pathogen levels in acidic fruit juices by 3 to 4 log CFU/ml without adversely altering the organoleptic properties. This study opens a new outlook for combinatorial antimicrobial therapy. There is a need to develop effective antibacterial therapies for mitigating bacterial pathogens in food systems. We used a 3D checkerboard assay to ascertain a safe synergistic combination of food-grade components: vitamin C, copper, and the essential oil linalool. Individually, these constituents have to be added in large amounts to exert their antibacterial effect, which leads to unwanted organoleptic properties. The triple combination could exceptionally inhibit foodborne Gram-negative pathogens like and subsp. serovar Typhi at low concentrations (linalool, 1.298 mM; vitamin C, 8 mM; copper, 16.3 μM) and displayed potent microbial inhibition in acidic beverages. We found increased susceptibility in deletion mutants of oxidative stress regulators (, , , and mutants) due to ROS generation by Fenton's chemistry. The results of this study show that it may be possible to use plant-based antimicrobials in synergistic combinations to control microbial contaminants.
Topics: Acyclic Monoterpenes; Anti-Bacterial Agents; Ascorbic Acid; Copper; DNA Damage; Drug Combinations; Drug Synergism; Escherichia coli; Humans; Microbial Sensitivity Tests; Microbial Viability; Oils, Volatile; Reactive Oxygen Species; Salmonella enterica; Vibrio
PubMed: 30552187
DOI: 10.1128/AEM.02487-18 -
International Journal of Medical... Oct 2014Vibrio furnissii and Vibrio fluvialis are two closely related species which are regarded as emerging human pathogens. Human infections have been mainly associated with... (Comparative Study)
Comparative Study
Vibrio furnissii and Vibrio fluvialis are two closely related species which are regarded as emerging human pathogens. Human infections have been mainly associated with consumption of seafood or drinking of contaminated water. V. furnissii strains can be distinguished from V. fluvialis by their ability to produce gas from fermentation of carbohydrates. In this study, we compare two phenotypic (biochemical testing and matrix-assisted laser desorption/ionisation time of flight mass spectrometry, MALDI-TOF MS) and three genotypic techniques (rpoB sequencing, conventional PCR and real-time PCR) for determination of the two species. The methods were evaluated on a collection of 42 V. furnissii and 32 V. fluvialis strains, which were isolated from marine environments and from animals intended for food production. Four of the applied methods allowed the unambiguous discrimination of the two species, while the biochemical testing was the least reliable technique, due to a high variation in the phenotype of gas production from carbohydrates. In view of the One Health concept reliable diagnostic techniques are a prerequisite for preventive public health measurements, as pathogens isolated from animals can cross species borders and methods for detection of sources, reservoirs and ways of transmission of pathogenic bacteria are indispensable for the prevention of infectious diseases in humans and animals.
Topics: Animals; Bacterial Typing Techniques; Bacteriological Techniques; DNA-Directed RNA Polymerases; Humans; Molecular Diagnostic Techniques; Molecular Sequence Data; Seafood; Sequence Analysis, DNA; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Vibrio; Water Microbiology
PubMed: 25242722
DOI: 10.1016/j.ijmm.2014.09.001 -
Frontiers in Microbiology 2018, an emerging foodborne pathogen of increasing public health concern, contains two distinct gene clusters encoding type VI secretion system (T6SS), the most newly...
, an emerging foodborne pathogen of increasing public health concern, contains two distinct gene clusters encoding type VI secretion system (T6SS), the most newly discovered secretion pathway in Gram-negative bacteria. Previously we have shown that one of the two T6SS clusters, namely VflT6SS2, is active and associates with anti-bacterial activity. However, how its activity is regulated is not completely understood. Here, we report that the global regulator integration host factor (IHF) positively modulates the expression and thus the function of VflT6SS2 through co-regulating its major cluster and 22 (also known as ) orphan clusters. Specifically, reporter gene activity assay showed that IHF transactivates the major and orphan clusters of VflT6SS2, while deletion of either or , the genes encoding the IHF subunits, decreased their promoter activities and mRNA levels of 2, , and 2 for the selected major cluster genes and 2 and 2 for the selected orphan cluster genes. Subsequently, the direct bindings of IHF to the promoter regions of the major and orphan clusters were confirmed by electrophoretic mobility shift assay (EMSA). Site-directed mutagenesis combined with reporter gene activity assay or EMSA pinpointed the exact binding sites of IHF in the major and orphan cluster promoters, with two sites in the major cluster promoter, consisting with its two observed shifted bands in EMSA. Functional studies showed that the expression and secretion of hemolysin-coregulated protein (Hcp) and the VflT6SS2-mediated antibacterial virulence were severely abrogated in the deletion mutants of Δ and Δ, but restored when their trans-complemented plasmids were introduced, suggesting that IHF mostly contributes to environmental survival of . by directly binding and modulating the transactivity and function of VflT6SS2.
PubMed: 29867866
DOI: 10.3389/fmicb.2018.00962 -
International Journal of Systematic and... Feb 2020Two Gram-staining-negative, facultatively anaerobic, motile, short clavate and flagellated marine bacteria, designated strains BEI233 and LJC006, were isolated from the...
Two Gram-staining-negative, facultatively anaerobic, motile, short clavate and flagellated marine bacteria, designated strains BEI233 and LJC006, were isolated from the East China Sea. On the basis of the results of 16S rRNA gene sequencing and multilocus sequence analysis, BEI233 and LJC006 should be assigned to the genus . The closest phylogenetic relatives of BEI233 are LMG 19158 (98.7 % 16S rRNA gene sequence pairwise similarity), DSM 14397 (98.5 %), KCTC 42287 (97.7 %), ATCC 35048 (97.3 %) and MD16 (96.5 %), whereas for LJC006 they were CAIM 518 (97.1 %), LMG 7894 (97.0%), JCM 16456 (96.9 %) and LMG 21346 (96.1 %). The growth of BEI233 occurred at 10-37 °C, pH 5.0-8.0 and with 1-7 % (w/v) NaCl, while the growth of LJC006 occurred at 10-37 °C, pH 6.0-9.0, and 0-8 % (w/v) NaCl. The predominant fatty acids (>10 %) were summed feature 3 (Cω7 or/and Cω6), C and summed feature 8 (Cω7 or/and Cω6), with different proportions. The DNA G+C contents of BEI233 and LJC006 are 42.41 mol% and 41.88 mol%, respectively. On the basis of the results of polyphasic analysis, BEI233 and LJC006 are considered to represent novel species of the genus for which the names sp. nov. and sp. nov. are proposed. The type strains are BEI233 (=JCM 32692=KCTC 62618) and LJC006 (=JCM 32693=KCTC 62620), respectively.
Topics: Bacterial Typing Techniques; Base Composition; China; DNA, Bacterial; Fatty Acids; Multilocus Sequence Typing; Nucleic Acid Hybridization; Phylogeny; RNA, Ribosomal, 16S; Seawater; Sequence Analysis, DNA; Vibrio
PubMed: 31702534
DOI: 10.1099/ijsem.0.003842 -
Frontiers in Microbiology 2016Resistance of various pathogens toward quinolones has emerged as a serious threat to combat infections. Analysis of plethora of genes and resistance mechanisms...
Resistance of various pathogens toward quinolones has emerged as a serious threat to combat infections. Analysis of plethora of genes and resistance mechanisms associated with quinolone resistance reveals chromosome-borne and transferable determinants. qnr genes have been found to be responsible for transferable quinolone resistance. In the present work, a new allele qnrVC5 earlier reported in Vibrio fluvialis from this laboratory was characterized in detail for its sequence, genetic context and propensity to decrease the susceptibility for quinolones. The study has revealed persistence of qnrVC5 in clinical isolates of V. fluvialis from Kolkata region through the years 2002-2006. qnrVC5 existed in the form of a gene cassette with the open reading frame being flanked by an upstream promoter and a downstream V. cholerae repeat region suggestive of its superintegron origin. Sequence analysis of different qnrVC alleles showed that qnrVC5 was closely related to qnrVC2 and qnrVC4 and these alleles were associated with V. cholerae repeats. In contrast, qnrVC1, qnrVC3, and qnrVC6 belonging to another group were associated with V. parahaemolyticus repeats. The gene manifested its activity in native V. fluvialis host as well as in Escherichia coli transformants harboring it by elevating the MIC toward various quinolones by twofold to eightfold. In combination with other quinolone resistance factors such as topoisomerase mutations and aac(6')-Ib-cr gene, qnrVC5 gene product contributed toward higher quinolone resistance displayed by V. fluvialis isolates. Silencing of the gene using antisense peptide nucleic acid sensitized the V. fluvialis parent isolates toward ciprofloxacin. Recombinant QnrVC5 vividly demonstrated its role in conferring quinolone resistance. qnrVC5 gene, its synergistic effect and global dissemination should be perceived as a menace for quinolone-based therapies.
PubMed: 26913027
DOI: 10.3389/fmicb.2016.00146 -
Tropical Biomedicine Dec 2022Some of Vibrio species is well known as pathogenic bacteria in aquaculture and the marine industry. Its infection is able to generate a massive outbreak and affect the...
Some of Vibrio species is well known as pathogenic bacteria in aquaculture and the marine industry. Its infection is able to generate a massive outbreak and affect the fish population, especially for net caged fish such as seabass. This study was conducted to investigate the prevalence of Vibrio spp. isolated from seabass (Lates calcarifer) in Sri Tujuh Lagoon, Tumpat, Kelantan. Then, to determine the antibiotic resistance in Vibrio isolates. Polymerase chain reaction (PCR) was used to detect Vibrio species using specific primer VR169 and VR744 with estimation base pair size band, 597 bp and further identified by sequencing. On the other hand, antibiotic susceptibility tests were continued by using 13 types of antibiotics; kanamycin (K30), chloramphenicol (C30), neomycin (N10), ampicillin (AMP10), nitrofurantoin (F300), tetracycline (TE30), streptomycin (S10), norfloxacin (NOR10), ciprofloxacin (CIP5), nalidixic acid (NA30), gentamicin (CN10), doxycycline (DO30) and sulfamethoxazole (SXT100). As a result, 14 Vibrio isolates were identified, including Vibrio fluvialis (n=6), Vibrio parahaemolyticus (n=3), Vibrio harveyi (n=2) and each isolate for Vibrio vulnificus, Vibrio alginolyticus and Vibrio spp. The results showed that all isolates were sensitive to most antibiotics except ampicillin, neomycin and streptomycin. The MAR index value was ranging from 0 to 0.31. This study demonstrates the prevalence of Vibrio spp. in seabass and the report on multidrug resistance strains that could be of concern to the fish farmers. In addition, data from this study can be further used in fish disease management plans.
Topics: Animals; Vibrio; Microbial Sensitivity Tests; Bass; Anti-Bacterial Agents; Neomycin; Ampicillin; Streptomycin
PubMed: 36602217
DOI: 10.47665/tb.39.4.013 -
Plants (Basel, Switzerland) Aug 2022L. essential oil (cumin EO) was studied for its chemical composition, antioxidant and vibriocidal activities. Inhibition of biofilm formation and secretion of some...
L. essential oil (cumin EO) was studied for its chemical composition, antioxidant and vibriocidal activities. Inhibition of biofilm formation and secretion of some virulence properties controlled by the quorum sensing system in and strains were also reported. The obtained results showed that cuminaldehyde (44.2%) was the dominant compound followed by β-pinene (15.1%), γ-terpinene (14.4%), and -cymene (14.2%). Using the disc diffusion assay, cumin EO (10 mg/disc) was particularly active against all fifteen species, and the highest diameter of growth inhibition zone was recorded against (41.33 ± 1.15 mm), (39.67 ± 0.58 mm), and (36.67 ± 0.58 mm). At low concentration (MICs value from 0.023-0.046 mg/mL), cumin EO inhibited the growth of all strains, and concentrations as low as 1.5 mg/mL were necessary to kill them (MBCs values from 1.5-12 mg/mL). Using four antioxidant assays, cumin EO exhibited a good result as compared to standard molecules (DPPH = 8 ± 0.54 mg/mL; reducing power = 3.5 ± 0.38 mg/mL; β-carotene = 3.8 ± 0.34 mg/mL; chelating power = 8.4 ± 0.14 mg/mL). More interestingly, at 2x MIC value, cumin EO inhibited the formation of biofilm by (9.96 ± 1%), (15.45 ± 0.7%), (14.9 ± 0.4%), and (18.14 ± 0.3%). In addition, cumin EO and cuminaldehyde inhibited the production of violacein on Lauria Bertani medium (19 mm and 35 mm, respectively). Meanwhile, 50% of violacein inhibition concentration (VIC) was about 2.746 mg/mL for cumin EO and 1.676 mg/mL for cuminaldehyde. Moreover, elastase and protease production and flagellar motility in were inhibited at low concentrations of cumin EO and cuminaldehyde. The adopted in-silico approach revealed good ADMET properties as well as a high binding score of the main compounds with target proteins (1JIJ, 2UV0, 1HD2, and 3QP1). Overall, the obtained results highlighted the effectiveness of cumin EO to prevent spoilage with species and to interfere with the quorum sensing system in Gram-negative bacteria by inhibiting the flagellar motility, formation of biofilm, and the secretion of some virulence enzymes.
PubMed: 36079620
DOI: 10.3390/plants11172236