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Applied and Environmental Microbiology Apr 2021By characterizing the trajectories of antibiotic resistance gene transfer in bacterial communities such as the gut microbiome, we will better understand the factors that...
By characterizing the trajectories of antibiotic resistance gene transfer in bacterial communities such as the gut microbiome, we will better understand the factors that influence this spread of resistance. Our aim was to investigate the host network of a multidrug resistance broad-host-range plasmid in the culturable gut microbiome of zebrafish. This was done through and conjugation experiments with as the donor of the plasmid pB10:: When this donor was mixed with the extracted gut microbiome, only transconjugants of were detected. In separate matings between the same donor and four prominent isolates from the gut microbiome, the plasmid transferred to two of these four isolates, and , but not to and When these and transconjugants were the donors in matings with the same four isolates, the plasmid now also transferred from to was unable to donate the plasmid, and was unable to acquire it. Finally, when the donor was added to zebrafish through their food, plasmid transfer was observed in the gut, but only to , a rare member of the gut microbiome. This work shows that the success of plasmid-mediated antibiotic resistance spread in a gut microbiome depends on the donor-recipient species combinations and therefore their spatial arrangement. It also suggests that rare gut microbiome members should not be ignored as potential reservoirs of multidrug resistance plasmids from food. To understand how antibiotic resistance plasmids end up in human pathogens, it is crucial to learn how, where, and when they are transferred and maintained in members of bacterial communities such as the gut microbiome. To gain insight into the network of plasmid-mediated antibiotic resistance sharing in the gut microbiome, we investigated the transferability and maintenance of a multidrug resistance plasmid among the culturable bacteria of the zebrafish gut. We show that the success of plasmid-mediated antibiotic resistance spread in a gut microbiome can depend on which species are involved, as some are important nodes in the plasmid-host network and others are dead ends. Our findings also suggest that rare gut microbiome members should not be ignored as potential reservoirs of multidrug resistance plasmids from food.
Topics: Animals; Bacteria; Drug Resistance, Multiple, Bacterial; Female; Gastrointestinal Microbiome; Male; Plasmids; Zebrafish
PubMed: 33637574
DOI: 10.1128/AEM.02735-20 -
International Journal of Microbiology 2021is a Gram-negative bacterium that is closely related to and causes gastroenteritis in humans due to contaminated fish consumption and seafood. This bacterium was...
is a Gram-negative bacterium that is closely related to and causes gastroenteritis in humans due to contaminated fish consumption and seafood. This bacterium was isolated and identified from 238 analyzed samples of sea water, oysters, and fish. Twenty strains were identified as according to amplification of the gene, which is useful as a marker of identification of the species. The production of lipases, proteases, and nucleases was detected; 45% of the strains were able to produce thermonucleases and 40% were capable of producing hydroxamate-type siderophores, and the fragment of the gene was amplified in all of the strains. Seventy-five percent of strains showed cytopathic effect on Chinese hamster ovary (CHO) cells and destruction of the monolayer, and 100% of the strains were adherent on the HEp-2 cell line with an aggregative adherence pattern. The presence of virulence factors in strains obtained from fishery products suggests that another member of the genus could represent a risk to the consumer due to production of different metabolites that allows it to subsist in the host.
PubMed: 33628259
DOI: 10.1155/2021/8397930 -
Journal of AOAC International Jun 2021Vibrio mimicus is a seafood-borne bacterium involved in incidences of human infections following consumption of raw or undercooked seafood. Regular monitoring of seafood...
BACKGROUND
Vibrio mimicus is a seafood-borne bacterium involved in incidences of human infections following consumption of raw or undercooked seafood. Regular monitoring of seafood for V.mimicus is necessary for risk assessment and to establish mitigation measures.
METHOD
During the period 2017-2020, a total of 250 samples comprising finfish, shellfish, water, ice, and sediment samples were collected from fish markets, fish landing centers, and fish farms in the Ernakulum district on the Southwest coast of Kerala, India. V. mimicus was isolated using enrichment in alkaline peptone water for 18 h followed by plating on thiosulfate citrate bile salts sucrose agar and then incubated at 37°C for 18-24 h. The presumptive V. mimicus isolates were confirmed by biochemical characterization and molecularly with vmh gene-specific for V. mimicus.
RESULTS
The study revealed that the prevalence of V. mimicus is 5.6% in the total of samples screened. The highest occurrence was observed in brackish water fish (19%) followed by freshwater fish (18%) and marine fish (2%) samples. The study points out the risk of brackish water fishes as potential carriers of this pathogen. This requires preventive measures to mitigate health hazards associated with V. mimicus entering into the seafood production chain.
Topics: Animals; Fisheries; Fishes; Humans; India; Prevalence; Seafood; Vibrio mimicus
PubMed: 33484252
DOI: 10.1093/jaoacint/qsab001 -
Microorganisms Jan 2021is an emerging pathogen, mainly associated with contaminated seafood consumption. However, little is known about its evolution, biodiversity, and pathogenic potential....
is an emerging pathogen, mainly associated with contaminated seafood consumption. However, little is known about its evolution, biodiversity, and pathogenic potential. This study analyzes the pan-, core, and accessory genomes of nine strains. The core genome yielded 2424 genes in chromosome I (ChI) and 822 genes in chromosome II (ChII), with an accessory genome comprising an average of 10.9% of the whole genome for ChI and 29% for ChII. Core genome phylogenetic trees were obtained, and ATCC-33654 strain was the closest to the outgroup in both chromosomes. Additionally, a phylogenetic study of eight conserved genes (Z, A, B, , A, A, B, and H), including , , , and , clearly showed clade differentiation. The main virulence genes found in ChI corresponded with type I secretion proteins, extracellular components, flagellar proteins, and potential regulators, while, in ChII, the main categories were type-I secretion proteins, chemotaxis proteins, and antibiotic resistance proteins. The accessory genome was characterized by the presence of mobile elements and toxin encoding genes in both chromosomes. Based on the genome atlas, it was possible to characterize differential regions between strains. The pan-genome of encompassed 3539 genes for ChI and 2355 genes for ChII. These results give us an insight into the virulence and gene content of , as well as constitute the first approach to its diversity.
PubMed: 33477474
DOI: 10.3390/microorganisms9010191 -
Molecular and Cellular Probes Feb 2021A multiplex PCR (mPCR) assay was established to detect five pathogenic Vibrio species and Plesiomonas shigelloides. Twelve genes were included: ompW, ctxA, rfbN, and...
A multiplex PCR (mPCR) assay was established to detect five pathogenic Vibrio species and Plesiomonas shigelloides. Twelve genes were included: ompW, ctxA, rfbN, and wbfR from V. cholerae; tl, tdh, and trh from V. parahaemolyticus; toxR and vmhA from V. mimicus; toxR from V. fluvialis; vvhA from V. vulnificus; and the 23S rRNA gene from P. shigelloides. The specificity of the mPCR assay was 100% for the detection of 136 strains and the limits of detection (LoD) were 12.5-50 pg/reaction. The assay exhibited higher sensitivity than cultivation methods in the detection of APW cultures of 113 diarrhea samples. In the analysis of 369 suspected Vibrio populations from estuarine water samples, the specificity of the mPCR for V. cholerae and V. parahaemolyticus was 100% for both, while the sensitivities were 100% and 96.1%, respectively. The assay can be applied to screen enrichment cultures and suspected colonies from environmental and clinical samples.
Topics: Electrophoresis, Capillary; Estuaries; Humans; Multiplex Polymerase Chain Reaction; Plesiomonas; Sensitivity and Specificity; Vibrio; Water Microbiology
PubMed: 33338586
DOI: 10.1016/j.mcp.2020.101689 -
Fish & Shellfish Immunology Jan 2021The outer membrane protein U (OmpU) is a conserved outer membrane protein in a variety of pathogenic Vibrio species and has been considered as a vital protective antigen...
The outer membrane protein U (OmpU) is a conserved outer membrane protein in a variety of pathogenic Vibrio species and has been considered as a vital protective antigen for vaccine development. Vibrio mimicus (V. mimicus) is the pathogen causing ascites disease in aquatic animals. In this study, the prokaryotically expressed and purified His-tagged OmpU of V. mimicus (His-OmpU) was used as a subunit vaccine. The formalin inactivated V. mimicus, purified His tag (His-tag), and PBS were used as controls. The vaccinated yellow catfish were challenged with V. mimicus at 28 days post-vaccination, and the results showed that the His-OmpU and inactivated V. mimicus groups exhibited much higher survival rates than the His-tag and PBS groups. To fully understand the underlying mechanism, we detected the expression levels of several immune-related genes in the spleen of fish at 28 days post-vaccination and 24 h post-challenge. The results showed that most of the detected immune-related genes were significantly upregulated in His-OmpU and inactivated V. mimicus groups. In addition, we performed the serum bactericidal activity assay, and the results showed that the serum from His-OmpU and inactivated V. mimicus groups exhibited much stronger bactericidal activity against V. mimicus than those of His-tag and PBS groups. Finally, the serum agglutination antibody was detected, and the antibody could be detected in His-OmpU and inactivated V. mimicus groups with the antibody titers increasing along with the time post-vaccination, but not in His-tag or PBS group. Our data reveal that the recombinant OmpU elicits potent protective immune response and is an effective vaccine candidate against V. mimicus in yellow catfish.
Topics: Adhesins, Bacterial; Animals; Bacterial Vaccines; Catfishes; Fish Diseases; Immunogenicity, Vaccine; Vaccines, Subunit; Vibrio Infections; Vibrio mimicus
PubMed: 33285164
DOI: 10.1016/j.fsi.2020.11.030 -
Nature Microbiology Dec 2020The bacterial flagellum is the prototypical protein nanomachine and comprises a rotating helical propeller attached to a membrane-embedded motor complex. The motor...
The bacterial flagellum is the prototypical protein nanomachine and comprises a rotating helical propeller attached to a membrane-embedded motor complex. The motor consists of a central rotor surrounded by stator units that couple ion flow across the cytoplasmic membrane to generate torque. Here, we present the structures of the stator complexes from Clostridium sporogenes, Bacillus subtilis and Vibrio mimicus, allowing interpretation of the extensive body of data on stator mechanism. The structures reveal an unexpected asymmetric AB subunit assembly where the five A subunits enclose the two B subunits. Comparison to structures of other ion-driven motors indicates that this AB architecture is fundamental to bacterial systems that couple energy from ion flow to generate mechanical work at a distance and suggests that such events involve rotation in the motor structures.
Topics: Bacillus subtilis; Bacterial Proteins; Clostridium; Flagella; Molecular Motor Proteins; Rotation; Vibrio mimicus
PubMed: 32929189
DOI: 10.1038/s41564-020-0788-8 -
International Journal of Microbiology 2020The aim of this study was to characterise species of water samples collected from taps, boreholes, and dams in the North West province, South Africa, and assess...
The aim of this study was to characterise species of water samples collected from taps, boreholes, and dams in the North West province, South Africa, and assess biocontrol potentials of their bacteriophages. Fifty-seven putative isolates were obtained on thiosulfate-citrate-bile-salt-sucrose agar and identified using biochemical tests and species-specific PCRs. Isolates were further characterised based on the presence of virulence factors, susceptibility to eleven antibiotics, and biofilm formation potentials. Twenty-two (38.60%) isolates were confirmed as species, comprising (45.5%, = 10), (22.7%, = 5), (13.6%, = 3), (9.1%, = 2), and (9.1%, = 2). Three of the six virulent genes screened were positively amplified; four possessed the (18.18%) and (18.18%) genes, while the gene was harboured by 3 V. (13.64%) and one (4.55%) isolate. Isolates revealed high levels of resistance to cephalothin (95.45%), ampicillin (77.27%), and streptomycin (40.91%), while lower resistances (4.55%-27.27%) were recorded for other antimicrobials. Sixteen (72.7%) isolates displayed multiple antibiotic-resistant properties. Cluster analysis of antibiotic resistance revealed a closer relationship between isolates from different sampling sites. The species displayed biofilm formation potentials at 37°C (63.6, = 14), 35°C (50%, = 11), and 25°C (36.4%, = 8). Two phages isolated in this study (vB_VpM_SA3V and vB_VcM_SA3V) were classified as belonging to the family Myoviridae based on electron microscopy. These were able to lyse multidrug-resistant and strains. These findings not only indicate the presence of antibiotic-resistant virulent species from dam, borehole, and tap water samples that could pose a health risk to humans who either come in contact with or consume water but also present these lytic phages as alternative agents that can be exploited for biological control of these pathogenic strains.
PubMed: 32831847
DOI: 10.1155/2020/8863370 -
Journal of Food Science Aug 2020The bacterial biofilm formation index (BFI) is measured by a microtiter plate assay, and it is typically performed at 72 hr. However, the dynamics of biopolymer...
A new classification criterion for the biofilm formation index: A study of the biofilm dynamics of pathogenic Vibrio species isolated from seafood and food contact surfaces.
The bacterial biofilm formation index (BFI) is measured by a microtiter plate assay, and it is typically performed at 72 hr. However, the dynamics of biopolymer formation change during this incubation period. The aims of this study were to follow the biofilm formation dynamics of Vibrio strains isolated from samples of seafood and food contact surfaces (FCS) and to propose a new BFI classification criterion. Samples from seafood (136) and FCS (14) were collected from retail markets in Queretaro, Mexico. The presence of Vibrio spp. was determined, the strains were isolated, and the six major pathogenic species (V. cholerae, V. alginolyticus, V. fluvialis, V. parahaemolyticus, V. vulnificus, V. mimicus) were identified by PCR. The BFI of the isolates was determined by the microtiter plate method. Fifty-one strains were isolated and identified as V. alginolytivcus (25), V. vulnificus (12), V. cholerae (7), V. parahaemolyticus (6), and V. mimicus (1). A quantitative classification criterion of biofilm formation was proposed based on the following factors: BFI dynamics (no formation, continuous increase, and increase followed by decrease), time of maximum BFI (early: 24 hr; late: 48 to 72 hr), and degree of BFI (none, weak, moderate, and strong). A numerical value was assigned to each factor to correlate the resulting BFI profile with a risk level. Thirteen BFI profiles were observed, having risk level values from 0 to 10. Vibrio alginolyticus, V. cholerae, and V. vulnificus showed the highest BFI profile diversities, which included the riskiest profiles. The proposed BFI criterion describes the dynamics of bacterial biopolymer formation and associates them with the possible risk implications. PRACTICAL APPLICATION: In food processing environments, the presence of bacterial biofilms that could include foodborne pathogens might favor cross-contamination due to direct contact or biofilm dispersal into food products. The new quantitative classification criterion for biofilm formation considers their production dynamics over time, the biofilm quantity, and the level of biofilm dispersal. These characteristics are represented by a numerical value that reflects the level of risk associated with the presence of a biofilm-producing strain on a food contact surface.
Topics: Animals; Biofilms; Food Contamination; Food Microbiology; Mexico; Phylogeny; Seafood; Vibrio
PubMed: 32654171
DOI: 10.1111/1750-3841.15325 -
Journal of the Air & Waste Management... Jul 2020Gaseous chlorine dioxide (ClO) is one of the most promising air disinfectants. In this study, an ultra-low concentration of ClO gas (< 1.2 mg/m) was generated in an...
UNLABELLED
Gaseous chlorine dioxide (ClO) is one of the most promising air disinfectants. In this study, an ultra-low concentration of ClO gas (< 1.2 mg/m) was generated in an office at various levels of humidity and illuminance to investigate the decay law. The disinfection efficiency and metal corrosiveness of ultra-low concentrations of ClO gas were also studied using an experimental chamber. At 48% and 75% humidity, the decay rate constants of ClO gas were 0.0034 min and 0.0036 min, respectively. The rate of decline of the ClO concentration increased as the humidity of the environment increased. The decay rate constant of ClO gas at an illuminance of 76 lux and 3429 lux was 0.0034 min and 0.00427 min, respectively; hence, the decay rate increased with increased illumination. At a humidity of 72% and illuminance of 2112 lux, the decay rate constant reached 0.00880 min. The effects of humidity and illuminance on the attenuation of the ClO concentration were strongly synergistic. When the gas concentration was maintained below 0.9 mg/m, the disinfection rate of ClO on bacteria ( and ) exceeded 99.9%; thus, ClO gas exhibited a high disinfection efficiency. In addition, there was no corrosion to various metals by ClO under the same conditions. Consequently, gaseous ClO at ultra-low concentrations has a high sterilization efficiency and is non-corrosive to metals.
IMPLICATIONS
Humidity and illuminance can influence decay laws of extremely low concentration ClO gas. The gaseous ClO at ultra-low concentrations has a high sterilisation efficiency and is non-corrosive to metals.
Topics: Air Pollution, Indoor; Chlorine Compounds; Disinfectants; Disinfection; Humidity; Oxides; Pseudomonas aeruginosa; Staphylococcus aureus; Vibrio mimicus
PubMed: 32412353
DOI: 10.1080/10962247.2020.1769768