-
Frontiers in Immunology 2024, a gram-negative coccobacillus bacterium, can cause various infections in humans, including septic arthritis, diarrhea (traveler's diarrhea), gastroenteritis, skin and...
, a gram-negative coccobacillus bacterium, can cause various infections in humans, including septic arthritis, diarrhea (traveler's diarrhea), gastroenteritis, skin and wound infections, meningitis, fulminating septicemia, enterocolitis, peritonitis, and endocarditis. It frequently occurs in aquatic environments and readily contacts humans, leading to high infection rates. This bacterium has exhibited resistance to numerous commercial antibiotics, and no vaccine has yet been developed. Aiming to combat the alarmingly high infection rate, this study utilizes techniques to design a multi-epitope vaccine (MEV) candidate against this bacterium based on its aerolysin toxin, which is the most toxic and highly conserved virulence factor among the species. After retrieval, aerolysin was processed for B-cell and T-cell epitope mapping. Once filtered for toxicity, antigenicity, allergenicity, and solubility, the chosen epitopes were combined with an adjuvant and specific linkers to create a vaccine construct. These linkers and the adjuvant enhance the MEV's ability to elicit robust immune responses. Analyses of the predicted and improved vaccine structure revealed that 75.5%, 19.8%, and 1.3% of its amino acids occupy the most favored, additional allowed, and generously allowed regions, respectively, while its ERRAT score reached nearly 70%. Docking simulations showed the MEV exhibiting the highest interaction and binding energies (-1,023.4 kcal/mol, -923.2 kcal/mol, and -988.3 kcal/mol) with TLR-4, MHC-I, and MHC-II receptors. Further molecular dynamics simulations demonstrated the docked complexes' remarkable stability and maximum interactions, i.e., uniform RMSD, fluctuated RMSF, and lowest binding net energy. models also predict the vaccine will stimulate a variety of immunological pathways following administration. These analyses suggest the vaccine's efficacy in inducing robust immune responses against . With high solubility and no predicted allergic responses or toxicity, it appears safe for administration in both healthy and -infected individuals.
Topics: Humans; Artificial Intelligence; Aeromonas hydrophila; Diarrhea; Travel; Machine Learning; Vaccines; Epitopes, T-Lymphocyte; Adjuvants, Immunologic; Adjuvants, Pharmaceutic; Bacterial Toxins; Pore Forming Cytotoxic Proteins
PubMed: 38495891
DOI: 10.3389/fimmu.2024.1369890 -
Microbiology Spectrum May 2024Hospital sewage serves as a crucial reservoir for antibiotic resistance genes. As colistin and carbapenems are the last-resort antibiotics, the emergence of their...
Hospital sewage serves as a crucial reservoir for antibiotic resistance genes. As colistin and carbapenems are the last-resort antibiotics, the emergence of their resistance genes has become a significant concern in clinical settings. In this study, we found that two novel alleles (.43 and .2) with two carbapenemase genes ( and ) were encoded in a single strain isolated from hospital sewage. Our phylogenetic analysis revealed that the gene clustered with (with 95.55% amino acid identity), while the gene clustered with (with 68.68% amino acid identity). BLAST search against GenBank showed that was exclusively detected in spp. Mobile genetic elements were not found in the genetic context of , suggesting that the dissemination of in spp. may be dependent on vertical transfer or recombination. The was adjacent to a recombinase gene and flanked by two IS elements, indicating a potential mobilization mechanism mediated by recombination and/or ISs. The gene was located on an IncU plasmid and adjacent to an IS. In summary, our study provides evidence for spp. as one of the potential reservoirs of colistin and carbapenem resistance genes.IMPORTANCEThe study discovered two novel genes ( and ) and two carbapenemase genes ( and ) in a single strain retrieved from hospital sewage. Using phylogenetic analysis and comparative data evaluation, the study revealed the genetic relatedness and dissemination potential of the detected resistance genes. With the exclusive discovery that is only present in spp. and the lack of mobile genetic elements in its genetic context, there is a strong indication of limited dissemination. The identification of these four resistance genes in a single strain of provided valuable insights into their potential presence in this genus. This study revealed that hospital sewage functions as a significant reservoir for antibiotic resistance genes, including colistin and carbapenem resistance genes.
Topics: beta-Lactamases; Bacterial Proteins; Anti-Bacterial Agents; Drug Resistance, Multiple, Bacterial; Phylogeny; Aeromonas caviae; Microbial Sensitivity Tests; Sewage; Colistin; Carbapenems; Humans; Plasmids
PubMed: 38511954
DOI: 10.1128/spectrum.03685-23 -
Microbial Genomics May 2024spp. are commonly found in the aquatic environment and have been responsible for motile septicemia (MAS) in striped catfish, resulting in significant economic loss....
spp. are commonly found in the aquatic environment and have been responsible for motile septicemia (MAS) in striped catfish, resulting in significant economic loss. These organisms also cause a range of opportunistic infections in humans with compromised immune systems. Here, we conducted a genomic investigation of 87 isolates derived from diseased catfish, healthy catfish and environmental water in catfish farms affected by MAS outbreaks in eight provinces in Mekong Delta (years: 2012-2022), together with 25 isolates from humans with bloodstream infections (years: 2010-2020). Genomics-based typing method precisely delineated species while traditional methods such as PCR and MALDI-TOF were unable identify was found to be more prevalent than in both diseased catfish and human infections. sequence type (ST) 656 followed by ST251 were the predominant virulent species-lineages in diseased catfish (43.7 and 20.7 %, respectively), while diverse STs were found in humans with bloodstream infections. There was evidence of widespread transmission of ST656 and ST251 on striped catfish in the Mekong Delta region. ST656 and ST251 isolates carried a significantly higher number of acquired antimicrobial resistance (AMR) genes and virulence factors in comparison to other STs. They, however, exhibited several distinctions in key virulence factors (i.e. lack of type IV pili and enterotoxin in ), AMR genes (i.e. presence of carbapenemase in ), and accessory gene content. To uncover potential conserved proteins of spp. for vaccine development, pangenome analysis has unveiled 2202 core genes between ST656 and ST251, of which 78 proteins were in either outer membrane or extracellular proteins. Our study represents one of the first genomic investigations of the species distribution, genetic landscape, and epidemiology of in diseased catfish and human infections in Vietnam. The emergence of antimicrobial resistant and virulent strains underscores the needs of enhanced genomic surveillance and strengthening vaccine research and development in preventing diseases in catfish and humans, and the search for potential vaccine candidates could focus on core genes encoded for membrane and secreted proteins.
Topics: Animals; Catfishes; Vietnam; Aeromonas; Gram-Negative Bacterial Infections; Humans; Sepsis; Fish Diseases; Phylogeny; Genomics; Genome, Bacterial; Virulence Factors; Anti-Bacterial Agents
PubMed: 38739115
DOI: 10.1099/mgen.0.001248 -
Fish & Shellfish Immunology Jul 2024The efficacy of phoxim in treating bacterial sepsis in silver carp is significant, yet its underlying mechanism remains elusive. This study aimed to establish a model of...
The efficacy of phoxim in treating bacterial sepsis in silver carp is significant, yet its underlying mechanism remains elusive. This study aimed to establish a model of Aeromonas veronii infection in silver carp and subsequently treat the infected fish with 10 μg/L phoxim. Kidney and intestine samples from silver carp were collected for transcriptome analysis and assessment of intestinal microbial composition, with the aim of elucidating the mechanism underlying the efficacy of phoxim in treating bacterial sepsis in silver carp. The results of transcriptome and intestinal microbial composition analysis of silver carp kidney indicated that A. veronii infection could up-regulate the expression of il1β, il6, nos2, ctsl, casp3 et al., which means, signifying that the kidney of silver carp would undergo inflammation, induce apoptosis, and alter the composition of intestinal microorganisms. Phoxim immersion might enhance the energy metabolism of silver carp and change its intestinal microbial composition, potentially elevating the antibacterial infection resistance of silver carp. These findings may contribute to an understanding of how phoxim can effectively treat bacterial sepsis in silver carp.
Topics: Animals; Carps; Fish Diseases; Organothiophosphorus Compounds; Gram-Negative Bacterial Infections; Aeromonas veronii; Gastrointestinal Microbiome
PubMed: 38750706
DOI: 10.1016/j.fsi.2024.109628 -
Annals of Clinical Microbiology and... May 2024The population structure and the correlation between antimicrobial resistance (AMR) phenotypes and genotypes in Aeromonas species isolated from patients with...
BACKGROUND
The population structure and the correlation between antimicrobial resistance (AMR) phenotypes and genotypes in Aeromonas species isolated from patients with gastroenteritis are not well understood. The aims of the study were to: (1) investigate the antimicrobial susceptibility profiles of Aeromonas species isolated from patients with gastroenteritis; (2) explore the relationship between AMR genes and resistance phenotypes; and (3) describe the population structure of these isolates and provide evidence of transmission events among them.
METHODS
This microbiological survey was performed at the Microbiology Laboratory of the Emek Medical Center in Afula, Israel. Cultivation of Aeromonas was attempted from stool samples that tested positive by PCR. Antimicrobial susceptibility testing (AST) was performed using the Sensititre GN3F microdilution panel. Whole genome sequencing (WGS) was done using the Illumina NextSeq500/550 system. Phylogenetic studies involved multi-locus sequence typing (MLST) and core genome (cg) MLST. Resistance mechanisms were identified using the Comprehensive Antibiotic Resistance Database and compared with the AST results.
RESULTS
The study included 67 patient-unique isolates. The species that were identified included A. caviae (n = 58), A. dhakensis (n = 3), A. media (n = 2), A. veronii (n = 2) and A. hydrophila (n = 2). Isolates were almost uniformly susceptible to amikacin, gentamicin, aztreonam, cefepime, ceftazidime, ciprofloxacin and meropenem. All isolates with the exception of 1-2 isolates were resistant to ampicillin, cefazolin and ampicillin-sulbactam which was compatible with the presence of the bla genes. Variable resistance rates were observed to cefuroxime, cefoxitin, ceftriaxone, piperacillin-tazobactam that were not correlated with the presence of other β-lactamase genes. Resistance to tetracycline and trimethoprim-sulfamethoxazole correlated with the presence of tetA and sul1, respectively. The population structure of A. caviae was highly diverse with the minority of the isolates (16/57) clustering into six defined sequence types. A cgMLST-based distance of four genes was found in one pair of isolates, suggesting common source transmission.
CONCLUSIONS
A. caviae is the dominant species related to gastroenteritis and is characterized by a diverse population structure, with almost no evidence for common-source transmission. Resistance rates to most antimicrobial agents were low and partially matched with the presence of resistance genes.
Topics: Humans; Gastroenteritis; Aeromonas; Microbial Sensitivity Tests; Anti-Bacterial Agents; Genotype; Phylogeny; Gram-Negative Bacterial Infections; Whole Genome Sequencing; Multilocus Sequence Typing; Child; Phenotype; Adult; Feces; Child, Preschool; Female; Male; Middle Aged; Drug Resistance, Bacterial; Israel; Aged; Infant; Adolescent; Young Adult; Drug Resistance, Multiple, Bacterial
PubMed: 38783344
DOI: 10.1186/s12941-024-00706-2 -
Frontiers in Microbiology 2024Strawberry ( × ) fruits are vulnerable to bacterial contamination; some species are pathogenic and can affect human health. Comprehending the bacterial composition and...
BACKGROUND
Strawberry ( × ) fruits are vulnerable to bacterial contamination; some species are pathogenic and can affect human health. Comprehending the bacterial composition and diversity at different ripe stages is a key determinant of the fruit health, productivity, and quality.
METHODOLOGY
An amplicon metagenomic approach on the 16S rRNA region was used to identify the bacterial diversity in exocarp of fruits collected from a farm field at two ripe stages: breaking (white, phase two) and ripe (red, phase four) and purchased from different retail market stands at ripe (red, phase four, ready-to-eat) stage. Besides, the fruit quality was assessed.
RESULTS
Strawberries carries a high microorganisms diversity, with , and being the most abundant families across the samples. Among the groups, and were the most abundant families at breaking (phase two) and ripe (phase four), whereas , and were the most abundant families in the market group. Although samples from group four-field and market were at the same ripe stage, the bacterial species composition was divergent. spp. were prevalent (above 60%) in samples collected from the market group, and (above 70%) species were mostly found in the samples collected from the field settings regardless of the phase. Besides, and were detected in the ready-to-eat samples from both the field and the market, while was detected in the samples that originated from the market. Interestingly, and , two human opportunistic pathogens, were detected in the fruits from the market only. According to alpha and beta diversity analyses, strawberry fruits displayed significant differences ( < 0.05) in bacterial communities within the ripe group, with the samples from the market showing the most bacterial diversity. Although we do not directly correlate the quality attributes with bacterial diversity, the results indicated a clear separation between groups according with their ripe stage and origin.
CONCLUSION
This study provides a comprehensive framework of the bacterial diversity throughout the transition from unripe to ripe strawberries which may aid in the development of preventative measures to manage the postharvest contamination.
PubMed: 38435684
DOI: 10.3389/fmicb.2024.1348316 -
Journal of Fish Diseases Apr 2024Aeromonas jandaei is a gram-negative bacterium commonly found in aquatic environments and can induce illnesses in amphibians, reptiles and aquatic animals. In this...
Aeromonas jandaei is a gram-negative bacterium commonly found in aquatic environments and can induce illnesses in amphibians, reptiles and aquatic animals. In this study, a strain of bacteria was isolated from the diseased Chinese soft-shell turtle (Pelodiscus sinensis), then named strain JDP-FX. This isolate was identified as A. jandaei after analysis of morphological, physiological and biochemical characteristics, as well as 16S rRNA and gyrB gene sequences. Virulence genetic testing further detected temperature-sensitive protease (eprCAI), type III secretion system (TTSS) (ascv), nuclease (nuc), cytotonic enterotoxin (alt) and serine proteinase (ser) in JDP-FX. Compared with healthy Chinese soft-shell turtle, the serum levels of total protein (TP), albumin (ALB) and globulin (GLB) were significantly decreased in the diseased Chinese soft-shell turtle, while, the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were significantly increased. Histopathological observations showed that multiple tissues, including intestinal mucosa, liver and kidney, were severely damaged in the diseased Chinese soft-shell turtle. Moreover, the diseased Chinese soft-shell turtle had significant cell degeneration, necrosis, sloughing and interstitial inflammatory cell infiltration. The pathogenicity of JDP-FX was tested via artificial infection. The median lethal dosage (LD ) of the strain was 1.05 × 10 colony forming units (CFU/g) per weight of Chinese soft-shell turtle. Drug susceptibility analysis revealed that JDP-FX was susceptible to ceftazidime, minocycline, cefoperazone, ceftriaxone and piperacillin. In addition, JDP-FX was resistant to doxycycline, florfenicol, sulfonamides, gentamicin, ampicillin and neomycin. Therefore, this study may provide guidance for further research into the diagnosis, prevention and treatment of JDP-FX infection.
Topics: Animals; Turtles; RNA, Ribosomal, 16S; Fish Diseases; China; Aeromonas
PubMed: 38217353
DOI: 10.1111/jfd.13919 -
Journal of Fish Diseases Aug 2023In this study, RNAi technology was used to silence the gene rstA in Aeromonas hydrophila. The strain rstA-RNAi displayed significant decrease in intracellular survival...
In this study, RNAi technology was used to silence the gene rstA in Aeromonas hydrophila. The strain rstA-RNAi displayed significant decrease in intracellular survival compared with that of the wild-type strain B11. Transcriptome analysis explored that the expression of some important anti-stress protein genes was significantly upregulated in rstA-RNAi compared with the wild-type strain, while the expression of the genes related to iron acquisition and type VI secretion system was significantly downregulated. Further study found that under low pH and H O stress, the anti-stress protein genes were expressed at a low level in rstA-RNAi, the growth ability of rstA-RNAi was also significantly lower than that of wild-type strain. The results also displayed that with the fluctuation of iron concentration, the expression of some genes related to iron acquisition remained at a low level in rstA-RNAi, and the growth ability of rstA-RNAi was lower than that of the wild-type strain under the same culture conditions, indicating rstA can regulate iron acquisition and further affect the bacteria growth. The adhesion ability of rstA-RNAi to fish macrophages was reduced, suggesting rstA may be also affect the formation of type VI secretion system of A. hydrophila.
Topics: Animals; Bacterial Proteins; Aeromonas hydrophila; Type VI Secretion Systems; Fish Diseases; Fishes; Iron; Gram-Negative Bacterial Infections
PubMed: 37171060
DOI: 10.1111/jfd.13790 -
Frontiers in Immunology 2024, a bacterium widely distributed in the natural environment, causes multiple diseases in various animals. Exploring the mechanism of the host defense against can help...
Integrated time-series biochemical, transcriptomic, and metabolomic analyses reveal key metabolites and signaling pathways in the liver of the Chinese soft-shelled turtle () against infection.
INTRODUCTION
, a bacterium widely distributed in the natural environment, causes multiple diseases in various animals. Exploring the mechanism of the host defense against can help develop efficient strategies against infection.
METHODS
Herein, we investigated the temporal influence of A. hydrophila on the Chinese soft-shelled turtle, an economically important species, at the biochemical, transcriptomic, and metabolomic levels. Plasma parameters were detected with the test kits. Transcriptome and metabolome were respectively applied to screen the differentially expressed genes and metabolites.
RESULTS
The contents or activities of these plasma parameters were significantly increased at 24 hpi and declined at 96 hpi, indicating that 24 and 96 hpi were two important time points during infection. Totals of 3121 and 274 differentially expressed genes (DEGs) from the transcriptome while 74 and 91 differentially abundant metabolites (DAMs) from the metabolome were detected at 24 and 96 hpi. The top DEGs at 24 hpi included and while and were the most abundant at 96 hpi. The predominant DAMs included O-phospho-L-serine, γ-Aminobutyric acid, orotate, L-tyrosine, and L-tryptophan at 24 hpi, as well as L-glutamic acid, L-arginine, glutathione, glutathione disulfide, and citric acid at 96 hpi.
DISCUSSION
The combined analysis of DEGs and DAMs revealed that tryptophan metabolism, nicotinate and nicotinamide metabolism, as well as starch and sucrose metabolism, were the most important signaling pathways at the early infective stage while tyrosine metabolism, pyrimidine metabolism, as well as alanine, aspartate and glutamate metabolism were the most crucial pathways at the later stage. In general, our results indicated that the Chinese soft-shelled turtle displays stage-specific physiological responses to resist infection.
Topics: Animals; Turtles; Aeromonas hydrophila; Gram-Negative Bacterial Infections; Signal Transduction; Metabolomics; Liver; Metabolome; Transcriptome; Gene Expression Profiling
PubMed: 38799475
DOI: 10.3389/fimmu.2024.1376860 -
Veterinary Research Communications Jun 2024The safety and effectiveness of oxytetracycline can potentially manage bacterial infections in fish. This, in turn, might reduce the concerns related to its use in...
Assessing safety, efficacy and residue depletion in golden mahseer, Tor putitora (Hamilton, 1822): biochemical and physiological responses to graded concentrations of oxytetracycline dietary supplementation.
The safety and effectiveness of oxytetracycline can potentially manage bacterial infections in fish. This, in turn, might reduce the concerns related to its use in aquaculture and human consumption, such as toxicity, antimicrobial resistance, and other associated risks. The primary objective of this study was to assess how adding oxytetracycline dihydrate to the diet affects its effectiveness, safety, and the presence of residues in T. putitora. T. putitora fingerlings, subjected to experimental infection with Aeromonas hydrophila at a concentration of 10 CFU mL, received an oral administration of oxytetracycline dihydrate. The oxytetracycline dihydrate was added to the feed (corresponding to 2% of the fish body weight) at concentrations of 44.1, 88.2, 132.3 and 176.4 mg Kg fish body weight per day. This treatment was carried out for 10 consecutive days. The biochemical and physiological responses of T. putitora and efficacy of oxytetracycline dihydrate were determined through estimation of microbial load (CFU mL), haematogram, serum biomarkers, behavioral characteristics, non-specific immunity and residue depletion. Experimentally infected fish showed disease progression and induced histopathological conditions with highest microbial load (CFU mL) in the muscle of both control and treated fish. The fish haematogram showed increased leucocyte and haemoglobin content, influenced by dietary oxytetracycline dihydrate. The fish demonstrated adaptive physiological response to oxytetracycline dihydrate at 44.1 to 88.2 mg and resulted in increased albumin and globulin content. The serum-enzyme assay showed significant increase in aspartate aminotransferase (AST), alanine aminotransferase (ALT) and plasma alkaline phosphatase (ALP) activities in the test fish (< 0.05). Oxytetracycline dihydrate at 88.2 to 132.3 mg Kg fish body weight per day recorded higher feed intake (75%), significant survivability (66-68%) and histopathological recovery. The suppressed immune response was manifested with decreased respiratory burst and lysozyme activity. The palatability, treatment of bacterial infection, histopathological changes and survivability by fingerlings of golden mahseer determined the safety and optimized the therapeutic potential of the oxytetracycline dihydrate at 88.2 mg Kg fish body weight per day for 10 days to contain the infection by A. hydrophila. A withdrawal period of 8-d was recommended as oxytetracycline dihydrate concentration depleted below the legal maximum residue limit (MRL 2.0 mg g) in the edible muscle of the golden mahseer reared at an average water temperature of 20 °C. This is considered safe for human consumption.
Topics: Animals; Oxytetracycline; Animal Feed; Fish Diseases; Dietary Supplements; Anti-Bacterial Agents; Cyprinidae; Diet; Drug Residues; Aeromonas hydrophila; Dose-Response Relationship, Drug; Gram-Negative Bacterial Infections
PubMed: 38409399
DOI: 10.1007/s11259-024-10340-0