-
International Journal of Food... Jan 2024This study aimed to explore the diversity of fifty-four Photobacterium strains isolated from muscle tissue of European plaice (Pleuronectes platessa) caught at different...
Insight to the diversity of Photobacterium spp. isolated from European plaice (Pleuronectes platessa) based on phylogenetic analysis, phenotypic characterisation and spoilage potential.
This study aimed to explore the diversity of fifty-four Photobacterium strains isolated from muscle tissue of European plaice (Pleuronectes platessa) caught at different fishing seasons and stored 14-days under various conditions. Single phylogenetic markers (16S rRNA, gapA, gyrB and recA) and multilocus sequence analysis (MLSA) were employed to classify isolates at species level. Furthermore, intra- and interspecies variability in the phenotypic traits, maximum specific growth rate (μ) and spoilage potential of the Photobacterium isolates were investigated. The isolates were classified into the P. iliopiscarium (53.7 %), P. phosphoreum (40.7 %) and P. piscicola (5.6 %) clades using MLSA. Two housekeeping genes, gyrB and recA, exhibited a consistent phylogenetic relationship with MLSA, suggesting that they might be used as individual phylogenetic markers for the Photobacterium genus. Intra- and interspecies variability in the expression of phenotypic characteristics and the production of trimethylamine (TMA), inosine (HxR), and hypoxanthine (Hx) were observed. A growth optimum temperature for P. iliopiscarium was approximately 20 °C, while those for P. phosphoreum and P. piscicola were closer to 15 °C. All isolates exhibited the highest growth density at 1.5 % NaCl, followed by 0.5 %, 3 %, and 6 % NaCl. However, P. phosphoreum demonstrated a higher NaCl tolerance than the other two species. Although, the high CO atmosphere significantly inhibited the growth of all strains at 4 °C, P. phosphoreum and P. piscicola showed higher growth density at 15 °C than P. iliopiscarium. Notably, all strains demonstrated HS production. The μ varied considerably within each species, highlighting the significance of strain-level variability. This study demonstrates that P. iliopiscarium and P. piscicola, alongside P. phosphoreum, are efficient TMA-, HxR-, Hx-, and HS-producers, suggesting their potential contribution to synergistic off-odour generation and spoilage. Moreover, the Photobacterium isolates seem to exhibit diverse adaptations to their environments, resulting in fluctuated growth and spoilage potential. Understanding intra- and interspecies variability will facilitate modelling seafood spoilage in microbial risk assessments and developing targeted hurdles to prolong products' shelf-life.
Topics: Animals; Phylogeny; Flounder; Photobacterium; RNA, Ribosomal, 16S; Sodium Chloride; Seafood
PubMed: 37984214
DOI: 10.1016/j.ijfoodmicro.2023.110485 -
Current Microbiology Mar 2020Histamine food poisoning is a major safety concern related to seafood consumption worldwide. Morganella psychrotolerans is a novel psychrotolerant histamine-producer. In...
Histamine food poisoning is a major safety concern related to seafood consumption worldwide. Morganella psychrotolerans is a novel psychrotolerant histamine-producer. In this study, the histamine production behaviors of M. psychrotolerans and two other major histamine-producers, mesophilic Morganella morganii and psychrotrophic Photobacterium phosphoreum, were compared in seafood products, and histamine accumulation by M. psychrotolerans was characterized at various pH and temperature levels in culture broth. The growth of M. psychrotolerans and P. phosphoreum increased similarly at 4 °C in canned tuna, but M. psychrotolerans produced much higher levels of histamine than P. phosphoreum. Histamine accumulation by M. psychrotolerans was induced at lower environmental pH condition at 4 and 20 °C. The optimal temperature and pH for producing histamine by crude histidine decarboxylase of M. psychrotolerans were 30 °C and pH 7, respectively. The activity of the crude HDC extracted from M. psychrotolerans cells at 10 °C retained 45% of the activity at 30 °C. Histidine decarboxylase gene expression of M. psychrotolerans was induced by low pH conditions. These results suggest that M. psychrotolerans are also a very important histamine-producer leading to histamine poisoning associated with seafood below the refrigeration temperature.
Topics: Animals; Consumer Product Safety; Culture Media; Foodborne Diseases; Histamine; Histidine Decarboxylase; Hydrogen-Ion Concentration; Morganella; Morganella morganii; Photobacterium; Seafood; Temperature; Tuna
PubMed: 31897663
DOI: 10.1007/s00284-019-01853-y -
Scientific Reports May 2019Tryptophan participates on several physiological mechanisms of the neuroendocrine-immune network and plays a critical role in macrophages and lymphocytes function. This...
Tryptophan participates on several physiological mechanisms of the neuroendocrine-immune network and plays a critical role in macrophages and lymphocytes function. This study intended to evaluate the modulatory effects of dietary tryptophan on the European seabass (Dicentrarchus labrax) immune status, inflammatory response and disease resistance to Photobacterium damselae piscicida. A tryptophan deficient diet (NTRP); a control diet (CTRL); and two other diets supplemented with tryptophan at 0.13% (TRP13) and 0.17% (TRP17) of feed weight were formulated. Fish were sampled at 2 and 4 weeks of feeding and the remaining were i.p. injected with Phdp (3 × 10 cfu/fish) at 4 weeks and the inflammatory response (at 4, 24, 48 and 72 hours post-infection) as well as survival were evaluated. Results suggest that fish immune status was not altered in a tryptophan deficient scenario whereas in response to an inflammatory insult, plasma cortisol levels increased and the immune cell response was compromised, which translated in a lower disease resistance. When dietary tryptophan was offered 30% above its requirement level, plasma cortisol increased and, in response to bacterial infection, a decrease in lymphocytes, monocytes/macrophages and several immune-related genes was observed, also compromising at some degree fish disease resistance.
Topics: Animal Feed; Animals; Bass; Blood Bactericidal Activity; Blood Cell Count; Body Weight; Complement Pathway, Alternative; Disease Resistance; Dose-Response Relationship, Drug; Erythrocyte Indices; Fish Diseases; Gene Expression Profiling; Gram-Negative Bacterial Infections; Hemoglobins; Hydrocortisone; Immunity, Humoral; Inflammation; Muramidase; Neuroimmunomodulation; Nutritional Requirements; Peroxidases; Photobacterium; Tryptophan
PubMed: 31118462
DOI: 10.1038/s41598-019-44205-3 -
Applied and Environmental Microbiology Jun 2017subsp. is a pathogen of marine animals, including fish of importance in aquaculture. The virulence plasmid pPHDD1, characteristic of highly hemolytic isolates, encodes...
subsp. is a pathogen of marine animals, including fish of importance in aquaculture. The virulence plasmid pPHDD1, characteristic of highly hemolytic isolates, encodes the hemolysins damselysin (Dly) and phobalysin (PhlyP). Strains lacking pPHDD1 constitute the vast majority of the isolates from fish outbreaks, but genetic studies to identify virulence factors in plasmidless strains are scarce. Here, we show that the chromosome I-encoded hemolysin PhlyC plays roles in virulence and cell toxicity in pPHDD1-negative isolates of this pathogen. By combining the analyses of whole genomes and of gene deletion mutants, we identified two hitherto uncharacterized chromosomal loci encoding a phospholipase (PlpV) and a collagenase (ColP). PlpV was ubiquitous in the subspecies and exerted hemolytic activity against fish erythrocytes, which was enhanced in the presence of lecithin. ColP was restricted to a fraction of the isolates and was responsible for the collagen-degrading activity in this subspecies. Consistent with the presence of signal peptides in PlpV and ColP sequences, mutants for the type II secretion system (T2SS) genes and exhibited impairments in phospholipase and collagenase activities. Sea bass virulence experiments and cell culture assays demonstrated major contributions of PhlyC and PlpV to virulence and toxicity. This study constitutes genetic and genomic analyses of plasmidless strains of an emerging pathogen in marine aquaculture, subsp. To date, studies on the genetic basis of virulence were restricted to the pPHDD1 plasmid-encoded toxins Dly and PhlyP. However, the vast majority of the recent isolates of this pathogen from fish farm outbreaks lack this plasmid. Here we demonstrate that the plasmidless strains produce two hitherto uncharacterized ubiquitous toxins encoded in chromosome I, namely, the hemolysin PhlyC and the phospholipase PlpV. We report the main roles of these two toxins in fish virulence and in cell toxicity. Our results constitute the basis for a better understanding of the virulence of a widespread marine pathogen.
Topics: Animals; Bass; Chromosomes, Bacterial; Collagenases; Fish Diseases; Gram-Negative Bacterial Infections; Hemolysin Proteins; Phospholipases; Photobacterium; Plasmids; Virulence
PubMed: 28341681
DOI: 10.1128/AEM.00401-17 -
Journal of Food Protection Apr 2018Uncontrolled bacterial growth and metabolic activities are responsible for the short shelf life of raw pork. Culture-independent analysis by 16S ribosome cDNA could...
Uncontrolled bacterial growth and metabolic activities are responsible for the short shelf life of raw pork. Culture-independent analysis by 16S ribosome cDNA could reveal viable bacteria in raw pork. This study investigated microbial growth and volatile organic compounds of raw pork supplemented with various preservatives. Vacuum-packaged raw pork was stored at 4°C, after soaking in solutions of potassium sorbate, ε-poly-l-lysine, kojic acid (KA), or sodium diacetate, individually. Spoilage of raw pork was monitored by determining pH and total volatile basic nitrogen, whereas bacterial growth was determined by culture-dependent and culture-independent analyses. Data indicated that all the preservatives were able to inhibit bacterial growth and extend the shelf life of pork. High-throughput sequencing of 16S ribosome cDNA indicated that Pseudomonas was inhibited under vacuum conditions, whereas facultative anaerobes ( Acinetobacter, Photobacterium, Brochothrix, and Myroides) were the most active genera in the spoiled pork. Photobacterium was further inhibited by each preservative. The inhibition of Acinetobacter, Photobacterium, and Myroides could be responsible for the extended shelf life of vacuum-packaged pork; they were effectively inhibited by KA, which also induced the longest shelf life. Moreover, 19 types of volatile organic compounds were detected. 3-Methylbutanol, 3-methylbutanol acetate, 2-butanone, toluene, benzeneacetaldehyde, dimethyl trisulfide, and acetoin were associated with spoilage. Furthermore, KA is a potential preservative in raw pork; because no phenol was detectable within 35 days, excessive intake of phenol induced by preservatives was avoided.
Topics: Animals; Food Microbiology; Food Packaging; Red Meat; Swine; Vacuum; Volatile Organic Compounds
PubMed: 29543526
DOI: 10.4315/0362-028X.JFP-17-423 -
Frontiers in Microbiology 2018subsp. () is an emerging pathogen of marine animals that sometimes causes serious infections in humans. Two related pore forming toxins, phobalysins P and C, and...
subsp. () is an emerging pathogen of marine animals that sometimes causes serious infections in humans. Two related pore forming toxins, phobalysins P and C, and damselysin, a phospholipase D, confer strong virulence of in mice. Because infections by are typically caused following exposure of wounds to sea water we investigated how salinity impacts toxin activity, swimming, and association of with epithelial cells. These activities were low when bacteria were pre-cultured in media with 3.5% NaCl, the global average salinity of sea water. In contrast, lower salinity increased swimming of wild type peaking at 2% NaCl, hemolysis, and association with epithelial cells peaking at 1-1.5%. Previously, we have found that hemolysin genes enhance the association of with epithelial cells, but the underlying mechanisms have remained ill-defined. We here searched for potential links between hemolysin-production, chemotaxis and association of with target cells at varying salt concentrations. Unexpectedly, disruption of chemotaxis regulator not only affected bacterial swimming and association with epithelial cells at intermediate to low salinity, but also reduced the production of plasmid-encoded phobalysin (PhlyP). The results thus reveal unforeseen links between chemotaxis regulators, a pore forming toxin and the association of a marine bacterium with target cells.
PubMed: 30619115
DOI: 10.3389/fmicb.2018.02996 -
Journal of Invertebrate Pathology Mar 2024Greenshell™ mussels (Perna canaliculus) are endemic to New Zealand and support the largest aquaculture industry in the country. Photobacterium swingsii was isolated...
Greenshell™ mussels (Perna canaliculus) are endemic to New Zealand and support the largest aquaculture industry in the country. Photobacterium swingsii was isolated and identified from moribund P. canaliculus mussels following a mass mortality event. In this study, a challenge experiment was used to characterise, detect, and quantify P. swingsii in adult P. canaliculus following pathogen exposure via injection into the adductor muscle. A positive control (heat-killed P. swingsii injection) was included to account for the effects of injection and inactive bacterial exposure. Survival of control and infected mussels remained 100% during 72-hour monitoring period. Haemolymph was sampled for bacterial colony counts and haemocyte flow cytometry analyses; histology sections were obtained and processed for histopathological assessments; and adductor muscle, gill, digestive gland were sampled for quantitative polymerase chain reaction (PCR) analyses, all conducted at 12, 24, 48 h post-challenge (hpc). The most profound effects of bacterial injection on mussels were seen at 48 hpc, where mussel mortality, haemocyte counts and haemolymph bacterial colony forming were the highest. The quantification of P. swingsii via qPCR showed highest levels of bacterial DNA at 12 hpc in the adductor muscle, gill, and digestive gland. Histopathological observations suggested a non-specific inflammatory response in all mussels associated with a general stress response. This study highlights the physiological effects of P. swingsii infection in P. canaliculus mussels and provides histopathological insight into the tissue injury caused by the action of injection into the adductor muscle. The multi-technique methods used in this study can be applied for use in early surveillance programs of bacterial infection on mussel farms.
Topics: Animals; Perna; New Zealand; Photobacterium; Disease Progression
PubMed: 38246322
DOI: 10.1016/j.jip.2024.108065 -
BMC Microbiology Apr 2013Phylogenetic hypotheses based on complete genome data are presented for the Gammaproteobacteria family Vibrionaceae. Two taxon samplings are presented: one including all...
BACKGROUND
Phylogenetic hypotheses based on complete genome data are presented for the Gammaproteobacteria family Vibrionaceae. Two taxon samplings are presented: one including all those taxa for which the genome sequences are complete in terms of arrangement (chromosomal location of fragments; 19 taxa) and one for which the genome sequences contain multiple contigs (44 taxa). Analyses are presented under the Maximum Parsimony and Maximum Likelihood optimality criteria for total evidence datasets, the two chromosomes separately, and individual analyses of locally collinear blocks. Three of the genomes included in the 44 taxon dataset, those of Vibrio gazogenes, Salinivibrio costicola, and Aliivibrio logei have been newly sequenced and their genome sequences are documented here.
RESULTS
Phylogenetic results for the 19-taxon datasets show similar levels of collinear subset of dataset incongruence as a previous study of 22 taxa from the sister family Shewanellaceae, while also echoing the strong phylogenetic performance of random subsets of data also shown in this study. Phylogenetic results for both the 19-taxon and 44-taxon datasets corroborate previous hypotheses about the placement of Photobacterium and Aliivibrio within Vibrionaceae and also highlight problems with how Photobacterium is delimited and indicate that it likely should be dissolved into Vibrio to produce a phylogenetic taxonomy. The 19-taxon and 44-taxon trees based on the large chromosome are congruent for the majority of taxa that are present in both datasets. Analyses of the 44-taxon sampling based on the second, small chromosome are quite different from those based on the large chromosome, which is not surprising given the dramatically divergent nature of the small chromosome and the difficulty in postulating primary homologies.
CONCLUSIONS
The phylogenetic analyses presented here represent the most comprehensive genome-level phylogenetic analyses in terms of taxa and data. Based on the availability of genome data for many bacterial species on GenBank, many other bacterial groups would also be amenable to similar genome-scale phylogenetic analyses even when present in multiple contigs. The result that collinear subsets of data are incongruent with the concatenated dataset and with each other while random data subsets show very little incongruence echoes the result of previous work on Shewanellaceae. The 44-taxon phylogenetic analysis presented here thus represents the future of phylogenomic analyses in scope and complexity.
Topics: DNA, Bacterial; Genome, Bacterial; Molecular Sequence Data; Phylogeny; Sequence Analysis, DNA; Vibrionaceae
PubMed: 23578061
DOI: 10.1186/1471-2180-13-80 -
Microorganisms Jul 2018subsp. () is responsible for disease outbreaks in marine aquaculture worldwide. , a valuable fish species for aquaculture in the south of Europe, is frequently...
subsp. () is responsible for disease outbreaks in marine aquaculture worldwide. , a valuable fish species for aquaculture in the south of Europe, is frequently affected by this pathogen. It is well established that bacteria respond to environmental signals and, in the case of pathogens, this ability may determine the outcome of their interaction with the host. Determination of gene expression under in vivo conditions constitutes a valuable tool in the assessment of microbial pathogenesis. Considering that different hosts may represent different environments for the pathogen, expression of virulence and in vivo induced antigen (IVIAT) genes during infection has been determined in the present work. Increased transcription of genes encoding proteins involved in iron acquisition (Irp1, Irp2, HutB and HutD), oxidative stress defence (AhpC and Sod), adhesion (PDP_0080), toxins (AIP56) and metabolism (Impdh, Shmt and AlaRS) were detected in infecting head kidney or liver. The highest increases corresponded to genes involved in survival under iron limiting conditions and oxidative stress, indicating their essential role during infection of sole. Results obtained give insight into virulence strategies and contribute to the identification of promising targets for the control of photobacteriosis.
PubMed: 30002314
DOI: 10.3390/microorganisms6030067 -
BMJ Case Reports Jun 2021subsp. is a family of and exists in the marine environment. The organism rarely causes soft-tissue infection in humans; moreover, most of the infected individuals...
subsp. is a family of and exists in the marine environment. The organism rarely causes soft-tissue infection in humans; moreover, most of the infected individuals have a history of fishing or exposure to brackish water. We experienced the case of a 63-year-old patient with a history of liver cirrhosis (Child-Pugh class B) who presented with a fever and swelling of the left leg with pain. His symptoms developed after fishing and eating raw fish with exposure of brackish water. He was diagnosed with cellulitis, and spp. was detected in blood culture. The patient was treated with ceftazidime and minocycline and he was discharged after recovery. We need to be aware that in immunocompromised patients with cellulitis exposed to brackish water, organisms other than and may be the causative organisms.
Topics: Animals; Bacteremia; Fish Diseases; Gram-Negative Bacterial Infections; Humans; Liver Cirrhosis; Male; Middle Aged; Photobacterium
PubMed: 34167981
DOI: 10.1136/bcr-2021-242580