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Frontiers in Microbiology 2021Aeromonas are Gram-negative rods widely distributed in the environment. They can cause severe infections in fish related to financial losses in the fish industry, and...
Aeromonas are Gram-negative rods widely distributed in the environment. They can cause severe infections in fish related to financial losses in the fish industry, and are considered opportunistic pathogens of humans causing infections ranging from diarrhea to septicemia. The objective of this study was to determine the contribution of genomic islands to . The complete genomes of 17 isolates, which were separated into two phylogenetic groups, were analyzed using a genomic island (GI) predictor. The number of predicted GIs and their characteristics varied among strains. Strains from group 1, which contains mainly fish pathogens, generally have a higher number of predicted GIs, and with larger size, than strains from group 2 constituted by strains recovered from distinct sources. Only a few predicted GIs were shared among them and contained mostly genes from the core genome. Features related to virulence, metabolism, and resistance were found in the predicted GIs, but strains varied in relation to their gene content. In strains from group 1, O Ag biosynthesis clusters OX1 and OX6 were identified, while strains from group 2 each had unique clusters. Metabolic pathways for myo-inositol, L-fucose, sialic acid, and a cluster encoding QueDEC, tgtA5, and proteins related to DNA metabolism were identified in strains of group 1, which share a high number of predicted GIs. No distinctive features of group 2 strains were identified in their predicted GIs, which are more diverse and possibly better represent GIs in this species. However, some strains have several resistance attributes encoded by their predicted GIs. Several predicted GIs encode hypothetical proteins and phage proteins whose functions have not been identified but may contribute to fitness. In summary, features with functions identified on predicted GIs may confer advantages to host colonization and competitiveness in the environment.
PubMed: 34912316
DOI: 10.3389/fmicb.2021.769380 -
Tropical Medicine & International... Feb 2023Aeromonas spp. often cause life-threatening diseases, including necrotizing fasciitis, which may lead to septic shock and ultimately death. Aeromonas infections are...
OBJECTIVES
Aeromonas spp. often cause life-threatening diseases, including necrotizing fasciitis, which may lead to septic shock and ultimately death. Aeromonas infections are believed to be transmitted via minor wounds or the consumption of fresh fish. However, after the detection of Aeromonas hydrophila in ticks in areas endemic to Japanese-spotted fever (JSF), a novel transmission route of A. hydrophila (i.e., via tick bites) has been proposed. We investigated the prevalence of A. hydrophila in ticks in areas endemic and not endemic to JSF in the Mie Prefecture, Japan.
METHODS
We collected ticks from endemic and nonendemic areas in summer and winter and assessed them for presence of A. hydrophila using polymerase chain reaction.
RESULTS
Six A. hydrophila isolates were obtained from 95 ticks in endemic areas, whereas one A. hydrophila isolate was obtained from 142 ticks in non-endemic areas, in summer. All ticks that harboured A. hydrophila were Haemaphysalis longicornis (H.L); these ticks were almost at the larval stage and also carried Rickettsia spp. in the endemic area. In contrast, 51 and 41 ticks in the endemic and non-endemic areas were captured in winter, respectively; A. hydrophila was not detected in these.
CONCLUSIONS
This study revealed the prevalence of tick-borne A. hydrophila. Therefore, the risk of transmission of A. hydrophila via a tick bite should be considered in the following conditions: areas abundant in H. L. harbouring Rickettsia spp., in areas endemic for JSF, presence of ticks in the larval stage and during the summer season.
Topics: Animals; Aeromonas hydrophila; Larva; Rickettsia; Spotted Fever Group Rickettsiosis; Ticks
PubMed: 36579736
DOI: 10.1111/tmi.13847 -
Vaccines May 2021is an important pathogen that causes motile septicemia (MAS) in the aquaculture industry. Aerolysin, hemolysin, serine protease and enterotoxins are considered to be...
is an important pathogen that causes motile septicemia (MAS) in the aquaculture industry. Aerolysin, hemolysin, serine protease and enterotoxins are considered to be the major virulence factors of . In this study, we constructed a five-gene (A, , , and ) deletion mutant strain (named five-gene deletion strain, AHFGDS) to observe the biological characteristics and detect its potential as a live-attenuated vaccine candidate. AHFGDS displayed highly attenuated and showed increased susceptibility to fish blood and skin mucus killing, while the wild-type strain ZYAH72 was highly virulent. In zebrafish (), AHFGDS showed a 240-fold higher 50% lethal dose (LD50) than that of the wild-type strain. Immunization with AHFGDS by intracelomic injection or immersion routes both provided grass carp () significant protection against the challenge of the strain ZYAH72 or J-1 and protected the fish organs from serious injury. Further agglutinating antibody titer test supported that AHFGDS could elicit a host-adaptive immune response. These results suggested the potential of AHFGDS to serve as a live-attenuated vaccine to control infection in aquaculture.
PubMed: 34063680
DOI: 10.3390/vaccines9050451 -
Metabolites Jul 2023The development of an exceptionally sensitive diagnostic technique for early identification of aquaculture diseases, specifically Aeromonas hydrophila, is essential for...
The development of an exceptionally sensitive diagnostic technique for early identification of aquaculture diseases, specifically Aeromonas hydrophila, is essential for efficient management of disease outbreaks at aquaculture locations. In this research, a swift and sensitive diagnostic assay employing Loop-mediated isothermal amplification (LAMP) of Aeromonas hydrophila was devised and compared to the conventional qPCR method documented by Rong Wang. Validation of the diagnostic assay was carried out using actual samples obtained from aquaculture fish. The findings revealed that based on the rapid detection of crude bacterial genomic DNA, the fluorescent LAMP assay possessed a lower limit of detection (LOD) of 0.559 ng/μL (0.315-1.693, 95% CI), while the LOD for qPCR stood at 4.301 ng/μL (2.084-8.876, 95% CI). Both techniques demonstrated outstanding specificity, exhibiting no cross-reactivity with bacteria from the same or closely related genera. A total of 74 fish samples suspected to be infected with the fish disease were gathered, with 26 and 23 samples testing positive for Aeromonas hydrophila via LAMP and qPCR, respectively. The concordance analysis for LAMP and qPCR methods generated a Kappa value of 0.909 (0.778-1.000, 95% CI), signifying a high degree of diagnostic consensus. This study highlights that the LAMP assay eliminates the thermal cycle temperature change process of qPCR, uses lysate to crudely extract bacterial genomic DNA, and can complete the detection within 40 min, rendering it a practical and efficient alternative for monitoring disease outbreaks at aquaculture sites.
PubMed: 37512548
DOI: 10.3390/metabo13070841 -
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 -
Veterinary World May 2021Malaysia is the world's major producer and exporter of ornamental fish, contributing 9% to the global trade and taking the second position after Singapore. Because of... (Review)
Review
Malaysia is the world's major producer and exporter of ornamental fish, contributing 9% to the global trade and taking the second position after Singapore. Because of their artistic appeal and tremendous commercial value for international trade, ornamental fish recently gain rapid importance for foreign exchange and as a source of employment. While ornamental fish production is growing, there is an increase in infectious diseases, resulting in high fish mortality with significant economic loss. Bacterial disease is a serious problem for ornamental fish industry. Bacterial species surveillance in diseased freshwater ornamental fish from an aquarium shop reveals that is the most dominant bacteria isolated. Consequently, Malaysia is stepping up its efforts by implementing the Economic Transformation Program and other biosecurity steps to address the aquaculture issues and encourage the regrowth of the ornamental fish market. Chemotherapeutic medications, phytobiotics, probiotics, yeast extracts, vaccines, and disinfectants can be used in controlling bacteria. Further studies should be done to find new antibacterial agents from natural sources to combat bacterial fish diseases and reduce fish mortality rate in sustainable aquaculture farms. This review summarizes the literature on ornamental fish industries and aquaculture production in relation to -associated diseases and ornamental fish health management in Malaysia.
PubMed: 34220115
DOI: 10.14202/vetworld.2021.1143-1152 -
Antimicrobial Resistance and Infection... Mar 2024Aeromonas hydrophila infections can cause gastrointestinal symptoms such as diarrhea; however, deep infections are rarely reported. Outbreaks of A. hydrophila are...
BACKGROUND
Aeromonas hydrophila infections can cause gastrointestinal symptoms such as diarrhea; however, deep infections are rarely reported. Outbreaks of A. hydrophila are reported more frequently in fish, poultry, and snakes than in humans. This study aimed to track clonal relatedness of deep infections caused by A. hydrophila using whole genome sequencing (WGS).
METHODS
We collected three isolates of A. hydrophila in July 19 to August 29, 2019, from patients that underwent spine surgery. Accurate species identification was performed using whole-genome average nucleotide identity (ANI). Antimicrobial susceptibility testing was performed using a VITEK 2 automated AST-N334 Gram-negative susceptibility card system. Antimicrobial resistance and virulence genes were identified using the Comprehensive Antibiotic Resistance Database and Virulence Factor Database VFanalyzer.
RESULTS
All three isolates were identified as A. hydrophila based on ANI and multilocus sequence typing analysis revealed that A. hydrophila belonged to a novel sequence type (ST1172). All three isolates were susceptible to amikacin and levofloxacin; however, they were resistant to piperacillin/tazobactam, ceftriaxone, cefuroxime, cefoxitin, and imipenem. Isolate 19W05620 (patient 3) showed increased ceftazidime resistance (minimum inhibitory concentration ≥ 64 µg/mL). All three isolates possessed the same chromosomally encoded β-lactamases, including bla (β-lactamase), imiH (metallo-β-lactamase), and bla (AmpC) in plasmids.
CONCLUSIONS
Our study validated the transmission of a novel carbapenem-resistant A. hydrophila sequence type (ST1172) in patients that underwent spine surgery. Control measures should be developed to prevent dissemination of A. hydrophila in the hospital setting.
Topics: Animals; Humans; Aeromonas hydrophila; Amikacin; Carbapenems; beta-Lactamases; Anti-Infective Agents
PubMed: 38433212
DOI: 10.1186/s13756-023-01339-4 -
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 -
Frontiers in Microbiology 2023is an emerging foodborne pathogen causing human gastroenteritis. species isolated from food such as seafood presented multidrug-resistance (MDR), raising serious...
is an emerging foodborne pathogen causing human gastroenteritis. species isolated from food such as seafood presented multidrug-resistance (MDR), raising serious concerns regarding food safety and public health. The use of phages to infect bacteria is a defense against drug-resistant pathogens. In this study, phage ZPAH34 isolated from the lake sample exerted lytic activity against MDR strain ZYAH75 and inhibited the biofilm on different food-contacting surfaces. ZPAH34 has a large dsDNA genome of 234 kb which belongs to a novel jumbo phage. However, its particle size is the smallest of known jumbo phages so far. Based on phylogenetic analysis, ZPAH34 was used to establish a new genus . Biological characterization revealed that ZPAH34 exhibited wide environmental tolerance, and a high rapid adsorb and reproductive capacity. Food biocontrol experiments demonstrated that ZPAH34 reduces the viable count of on fish fillets (2.31 log) and lettuce (3.28 log) with potential bactericidal effects. This study isolated and characterized jumbo phage ZPAH34 not only enriched the understanding of phage biological entity diversity and evolution because of its minimal virion size with large genome but also was the first usage of jumbo phage in food safety to eliminate .
PubMed: 37415809
DOI: 10.3389/fmicb.2023.1178876 -
Ecotoxicology and Environmental Safety Sep 2023Aeromonas hydrophila is a conditional pathogen impacting public hygiene and safety. Hemolysin is a virulence factor of Aeromonas hydrophila that causes erythrocyte...
Aeromonas hydrophila is a conditional pathogen impacting public hygiene and safety. Hemolysin is a virulence factor of Aeromonas hydrophila that causes erythrocyte hemolysis, yet its transcriptional response to Cyprinus rubrofuscus remains unknown. Our investigation confirmed the hemolysis of hemolysin from A. hydrophila. Serum enzyme activity was evaluated weekly after C. rubrofuscus were immunized with hemolysin Ahh1. The results showed that the hemolysin enhances the serum superoxide dismutase (SOD), lysozyme (LZM), and catalase (CAT) activity, which reached a maximum on day 14. To elucidate the molecular interaction between hemolysin from A. hydrophila and the host, we performed transcriptome sequencing on the spleen of C. rubrofuscus 14 days post hemolysin infection. The total number of clean reads was 41.37 Gb, resulting in 79,832 unigenes with an N50 length of 1863 bp. There were 1982 significantly differentially expressed genes (DEGs), including 1083 upregulated genes and 899 downregulated genes. Transcript levels of the genes, such as LA6BL, CD2, and NLRC5, were significantly downregulated, while those of IL11, IL1R2, and IL8 were dramatically upregulated. The DEGs were mainly enriched in the immune disease, viral protein interaction with cytokine and cytokine receptor, and toll-like receptor pathways, suggesting that hemolysin stimulation can activate the transcriptional responses. RT-qPCR experiments results of seven genes, IL-8, STAT2, CTSK, PRF1, CXCL9, TLR5, and SACS, showed that their expression was highly concordant with RNA-seq data. We clarified for the first time the key genes and signaling pathways response to hemolysin from A. hydrophila, which offers strategies for treating and preventing diseases.
Topics: Animals; Spleen; Aeromonas hydrophila; Hemolysin Proteins; Hemolysis; Carps
PubMed: 37591129
DOI: 10.1016/j.ecoenv.2023.115375