-
Veterinary Microbiology Aug 2023Aeromonas veronii is a Gram-negative opportunistic bacterium found in fish, poultry and humans and has occasionally been associated with disease although not generally...
Aeromonas veronii is a Gram-negative opportunistic bacterium found in fish, poultry and humans and has occasionally been associated with disease although not generally considered a poultry pathogen. A. veronii was recently isolated from both healthy and condemned broiler carcasses at a major Danish abattoir. In this study, we did a whole genomic analysis of 24A. veronii strains from the abattoir to determine their potential sources and relatedness as well as their pathogenic potential, antimicrobial resistance determinants and associated mobile elements. No strains were multi-drug resistant, but all strains carried the beta-lactam resistance genes cphA3 and bla without being phenotypically resistant to carbapenems. One strain carried an IncA plasmid with tet(A), tet(B) and tet(E) genes. A phylogenetic tree including public A. veronii sequences showed that our isolates were not clonal but were dispersed around the phylogenetic tree, suggesting a diffuse spread of A. veronii across human, aquatic and poultry samples. Strains carried different virulence factors known to be associated with pathogenesis and severity of disease in animals and humans, e.g. type II (aerolysin, amylases, proteases, and cytotoxic enterotoxin Act) and III secretion systems where the latter has been associated with mortality in hospitalized patients. Although our genomic analysis of A. veronii shows zoonotic potential, epidemiological studies of human gastro-enteritis cases of A. veronii associated with consumption of broiler meat are needed. It remains to be proven if A. veronii is a true poultry pathogen and part of the established microflora in abattoirs and the gut-intestinal microflora of poultry.
Topics: Humans; Animals; Aeromonas veronii; Aeromonas; Chickens; Virulence; Phylogeny; Genomics; Denmark; Gram-Negative Bacterial Infections
PubMed: 37207528
DOI: 10.1016/j.vetmic.2023.109772 -
Pathogens (Basel, Switzerland) Apr 2023A case of severe mortality in farmed was investigated to characterize the causative agent. We identified the bacterial strain as isolated from the gut of infected by...
A case of severe mortality in farmed was investigated to characterize the causative agent. We identified the bacterial strain as isolated from the gut of infected by biochemical assay, scanning electron microscopy and 16S rRNA gene sequence analysis. The in vivo challenge experiment showed that the LD of was 2.2 × 10 CFU/fish. Virulence gene investigation revealed that the isolated possesses Aerolysin, Cytotoxic enterotoxin, Serine protease, Dnase and Type III secretion system genes. The isolated strain was resistant to two antibiotics (ampicillin and dicloxacillin) while susceptible to 22 other antibiotics. The study further revealed that induced both stresses along with non-specific and specific immune responses marked by elevated cortisol HSP70, HSP90 and IgM levels in the treated fingerlings. Although the bacterial pathogen enhances the immune response, the negative effect on fish, including stress, and high mortality, create concern and a need for management in farms. The knowledge gained from this study would facilitate future research aimed at assessing the pathogenicity of , with an emphasis on microbial disease management in other farmed fish species.
PubMed: 37111485
DOI: 10.3390/pathogens12040598 -
Journal of Infection in Developing... Mar 2023Oncologic patients can have severe infections due to Aeromonas. This study aims to investigate the clinical characteristics and outcomes of cancer patients with...
INTRODUCTION
Oncologic patients can have severe infections due to Aeromonas. This study aims to investigate the clinical characteristics and outcomes of cancer patients with bloodstream infections (BSI) caused by Aeromonas.
METHODOLOGY
We included patients with bacteremia caused by Aeromonas species from 2011 to 2018.
RESULTS
Seventy-five BSI events in the same number of patients were identified. Forty patients were men (53.3%); the mean age was 49 years (IQR 28-61). A. caviae was the most frequent isolate (n = 29, 38.6%), followed by A. hydrophila (n = 23, 30.6%), A. sobria (n = 15, 20%), and A. veronii (n = 8, 10.6%). The most frequent underlying diagnosis was hematologic malignancy (n = 33, 44%), followed by breast cancer (n = 12, 16%) and gastrointestinal tract cancer (n = 8, 10.6%). The most frequent type of bacteremia was CRBSI in 32 cases (42.6%), followed by mucosal barrier injury-laboratory confirmed BSI (n = 20, 26.7%). Sixteen (26.2%) were hospital-acquired BSI. Attributable mortality occurred in 11 patients (14.6%). In univariate analysis A. hydrophila bacteremia, liver failure, skin/soft tissue infection, septic shock, inappropriate antimicrobial treatment, and relapse or cancer progression were associated with 30-day mortality. In multivariate analysis, only septic shock, inappropriate antimicrobial treatment, and relapse or cancer progression were associated with 30-day mortality.
CONCLUSIONS
Aeromonas species should be considered one of the causative pathogens of healthcare-associated bacteremia, especially in immunocompromised patients. In addition, it can be associated with high fatality, particularly in patients with severe clinical infections.
Topics: Male; Humans; Middle Aged; Female; Aeromonas; Shock, Septic; Neoplasm Recurrence, Local; Anti-Infective Agents; Bacteremia; Gram-Negative Bacterial Infections
PubMed: 37023428
DOI: 10.3855/jidc.17530 -
Frontiers in Microbiology 2023is a Gram-negative bacterium ubiquitously found in aquatic environments. It is a foodborne pathogen that causes diarrhea in humans and hemorrhagic septicemia in fish....
The mobile gene cassette carrying tetracycline resistance genes in strain Ah5S-24 isolated from catfish pond sediments shows similarity with a cassette found in other environmental and foodborne bacteria.
is a Gram-negative bacterium ubiquitously found in aquatic environments. It is a foodborne pathogen that causes diarrhea in humans and hemorrhagic septicemia in fish. In the present study, we used whole-genome sequencing (WGS) to evaluate the presence of antimicrobial resistance (AMR) and virulence genes found in Ah5S-24 isolated from catfish pond sediments in South-East, United States. We found , , , , , and resistance genes encoded in the chromosome of Ah5S-24. We also found the tetracycline and genes placed next to the ISIS transposase, integrase, and hypothetical proteins that formed as a genetic structure or transposon designated as ISIS. BLAST analysis showed that a similar mobile gene cassette (MGC) existed in chromosomes of other bacteria species such as isolated from retail fish at markets, from human stool and from a sewage bioreactor. In addition, the ISIS cassette was also found in the plasmid of isolated from shrimp. As for virulence genes, we found the tap type IV pili ( and ), polar flagellae ( and ), lateral flagellae ( and ), and fimbriae ( and ) genes responsible for motility and adherence. We also found the hemolysin genes (, and ), toxin, biofilm formation, and quorum sensing (, and ) genes. However, there were no MGCs encoding virulence genes found in AhS5-24. Thus, our findings show that MGCs could play a vital role in the spread of AMR genes between chromosomes and plasmids among bacteria in aquatic environments. Overall, our findings are suggesting that MGCs encoding AMR genes could play a vital role in the spread of resistance acquired from high usage of antimicrobials in aquaculture to animals and humans.
PubMed: 37007502
DOI: 10.3389/fmicb.2023.1112941 -
Ecotoxicology and Environmental Safety Apr 2023Intestinal inflammation is a protective response that is implicated in bacterial enteritis triggered by gastrointestinal infection. The immune mechanisms elicited in...
Intestinal inflammation is a protective response that is implicated in bacterial enteritis triggered by gastrointestinal infection. The immune mechanisms elicited in teleost against the infection of Aeromonas veronii are largely unknown. In this study, we performed a de novo northern snakehead (Channa argus) transcriptome assembly using Illumina sequencing platform. On this basis we performed a comparative transcriptomic analysis of northern snakehead intestine from A. veronii-challenge and phosphate buffer solution (PBS)-challenge fish, and 2076 genes were up-regulated and 1598 genes were down-regulated in the intestines infected with A. veronii. The Gene Ontology (GO) enrichment analysis indicated that the differentially expressed genes (DEGs) were enriched to 27, 21 and 20 GO terms in biological process, cellular component, and molecular function, respectively. A Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that 420 DEGs were involved in 194 pathways. Moreover, 33 DEGs were selected for quantitative real-time PCR analysis to validate the RNA-seq data. The results reflected the consistency of the expression levels between qRT-PCR and RNA-seq data. In addition, a time-course analysis of the mRNA expression of 33 immune-related genes further indicated that the intestinal inflammation to A. veronii infection simultaneously regulated gene expression alterations. The present study provides transcriptome data of the teleost intestine, allowing us to understand the mechanisms of intestinal inflammation triggered by bacterial pathogens. DATA AVAILABILITY STATEMENT: All data supporting the findings of this study are available within the article and Supplementary files. The RNA-seq raw sequence data are available in NCBI short read archive (SRA) database under accession number PRJNA615958.
Topics: Animals; Transcriptome; Aeromonas veronii; Gene Expression Profiling; Intestines; Immunity; Inflammation
PubMed: 36989948
DOI: 10.1016/j.ecoenv.2023.114825 -
Microorganisms Mar 2023Widespread and inappropriate use of antibiotics has been shown to increase the spread of antibiotics and antimicrobial resistance genes (ARGs) in aquatic environments...
Widespread and inappropriate use of antibiotics has been shown to increase the spread of antibiotics and antimicrobial resistance genes (ARGs) in aquatic environments and organisms. Antibiotic use for the treatment of human and animal diseases is increasing continuously globally. However, the effects of legal antibiotic concentrations on benthic consumers in freshwater environments remain unclear. In the present study, we tested the growth response of to florfenicol (FF) for 84 days under high and low concentrations of sediment organic matter (carbon [C] and nitrogen [N]). We characterized FF and sediment organic matter impact on the bacterial community, ARGs, and metabolic pathways in the intestine using metagenomic sequencing and analysis. The high concentrations of organic matter in the sediment impacted the growth, intestinal bacterial community, intestinal ARGs, and microbiome metabolic pathways of . growth increased significantly following exposure to high organic matter content sediment. Proteobacteria, at the phylum level, and at the genus level, were enriched in the intestines. In particular, fragments of four opportunistic pathogens enriched in the intestine of high organic matter content sediment groups, , , , and , carried 14 ARGs. The metabolic pathways of the intestine microbiome were activated and showed a significant positive correlation with sediment organic matter concentrations. In addition, genetic information processing and metabolic functions may be inhibited by the combined exposure to sediment C, N, and FF. The findings of the present study suggest that antibiotic resistance dissemination from benthic animals to the upper trophic levels in freshwater lakes should be studied further.
PubMed: 36985338
DOI: 10.3390/microorganisms11030765 -
Antibiotics (Basel, Switzerland) Mar 2023Antibiotic resistance (AR) remains one of the greatest threats to global health, and species have the potential to spread AR in the aquatic environment. The spread of...
Antibiotic resistance (AR) remains one of the greatest threats to global health, and species have the potential to spread AR in the aquatic environment. The spread of resistance to antibiotics important to human health, such as third-generation cephalosporins (3GCs) and carbapenems, is of great concern. We isolated and identified 15 cefotaxime (3GC)- and 51 carbapenem-resistant spp. from untreated hospital and treated municipal wastewater in January 2020. The most common species were (58%), (17%), (11%), and (11%). Almost all isolates exhibited a multidrug-resistant phenotype and harboured a diverse plasmidome, with the plasmid replicons ColE, IncU, and IncR being the most frequently detected. The most prevalent carbapenemase gene was the plasmid-associated and, for the first time, the , and genes were identified in spp. Among the 3GC-resistant isolates, the and genes were the most prevalent. Of the 10 isolates examined, three were capable of transferring carbapenem resistance to susceptible recipient . Our results suggest that conventionally treated municipal and untreated hospital wastewater is a reservoir for 3GC- and carbapenem-resistant, potentially harmful spp. that can be introduced into aquatic systems and pose a threat to both the environment and public health.
PubMed: 36978380
DOI: 10.3390/antibiotics12030513 -
Microbiology Spectrum Mar 2023Probiotics are an alternative strategy for antibiotics, but most probiotics are Gram-positive bacteria suitable for terrestrial animals. Therefore, it is imperative to...
Probiotics are an alternative strategy for antibiotics, but most probiotics are Gram-positive bacteria suitable for terrestrial animals. Therefore, it is imperative to develop dedicated probiotics for the common carp industry to be ecologically efficient and environmentally friendly. A novel Enterobacter asburiae named E7 was isolated from the intestine of healthy common carp and displayed an extensive antibacterial spectrum against Aeromonas hydrophila, A. veronii, A. caviae, A. media, A. jandaei, A. enteropelogenes, A. schubertii, A. salmonicida, Pseudomonas aeruginosa, Ps. putida, Plesiomonas shigelloides, and . E7 was nonpathogenic to the host and susceptible to the majority of antibiotics used in human clinical practice. E7 could grow between 10 and 45°C and between pH 4 and 7 and was extremely resistant to 4% (wt/vol) bile salts. Diets were supplemented with 1 × 10 CFU/g E7 for 28 days. No significant difference in the growth of fish was observed. Expression of immune-related genes , , and in common carp kidney was significantly upregulated at weeks 1, 2, and 4 ( < 0.01). A significant upregulation of , , and expression was observed after week 4 ( < 0.01). There was a significant increase in mRNA expression of at week 3 ( < 0.01). Following challenge by Aeromonas veronii, the survival rate (91.05%) was significantly higher than observed in the controls (54%; < 0.01). Collectively, E7 is a promising new Gram-negative probiotic that can enhance health and bacterial resistance of aquatic animals and could thus be developed as an exclusive aquatic probiotic. In the present study, we evaluated for the first time the efficiency of Enterobacter asburiae as a prospective probiotic for aquaculture applications. The E7 strain showed extensive resistance to , no pathogenicity to the host, and stronger environmental tolerance. We observed that the resistance of common carp to was enhanced by feeding a diet containing 1 × 10 CFU/g E7 for 28 days, but growth was not improved. Strain E7 can act as an immunostimulant to induce the upregulation of some innate cellular and humoral immune responses, resulting in enhanced resistance to . Hence, the continuous activation of immune cells can be maintained by adding suitable fresh probiotics to the diet. E7 has the potential to act as a probiotic agent for green, sustainable aquaculture and aquatic product safety.
PubMed: 36975994
DOI: 10.1128/spectrum.04273-22 -
Journal of Food Protection Apr 2023In Mexico, bullfrogs (Lithobates catesbeianus) are produced as gourmet food. However, bullfrogs can be carriers of pathogens because the frogs' preferred living...
In Mexico, bullfrogs (Lithobates catesbeianus) are produced as gourmet food. However, bullfrogs can be carriers of pathogens because the frogs' preferred living conditions occur in stagnant water. The present study aimed to identify bacteria that cause foodborne diseases or are associated with human diseases. For molecular identification, based on the sequential analysis by 16S rRNA or rpoD was conducted on all isolates obtained from bullfrog. A total of 91 bacterial isolates were obtained from bullfrogs; 14 genera and 23 species were identified, including Acinetobacter johnsonii 16.5%; Aeromonas media 14.3%; Aeromonas veronii 13.2%; Providencia rettgeri 7.7%; Citrobacter freundii 6.6%; Aeromonas caviae 4.4%; Aeromonas hydrophila and Elizabethkingia ursingii 3.3%; Pseudomonas stutzeri, Raoultella ornithinolytica, and Shewanella putrefaciens 2.2%; Acinetobacter guillouiae, Acinetobacter pseudolwoffii, Citrobacter portucalensis, Citrobacter werkmanii, Edwardsiella anguillarum, Klebsiella michiganensis, Kluyvera intermedia, Kocuria rosea, Myroides odoratimimus, Myroides odoratus, Proteus sp., and Proteus hauseri 1.1%. In this study, 49.4% of the isolates obtained cause foodborne disease, 19.8% are bacteria that play an important role in the spoilage of food, 5.5% of isolates have nosocomial significance, 13.2% of bacteria are considered to be pollutants of the ecosystem, and in the case of A. salmonicida and Edwardsiella anguillarum (12.1%) to have a negative impact on aquaculture. Acinetobacter pseudolwoffii and Citrobacter portucalensis have not been reported to cause disease. Lastly of these isolates, 97.8% (89/91) can cause disease by food consumption or by direct contact for immunocompromised persons. The presence of these bacteria in bullfrogs represents a significant problem for human health. There is evidence that these microorganisms are pathogenic and frogs may also be reservoirs.
Topics: Animals; Humans; Rana catesbeiana; Ecosystem; RNA, Ribosomal, 16S; Foodborne Diseases
PubMed: 36948016
DOI: 10.1016/j.jfp.2023.100067 -
Gut Microbes 2023In response to microbiota colonization, the intestinal epithelia of many animals exhibit increased rates of cell proliferation. We used gnotobiotic larval zebrafish to...
In response to microbiota colonization, the intestinal epithelia of many animals exhibit increased rates of cell proliferation. We used gnotobiotic larval zebrafish to identify a secreted factor from the mutualist that is sufficient to promote intestinal epithelial cell proliferation. This secreted protein is a homologue of the GlcNAc binding protein GbpA, which was identified as a chitin-binding colonization factor in mice. GbpA was subsequently shown to be a lytic polysaccharide monooxygenase (LPMO) that can degrade recalcitrant chitin. Our phenotypic characterization of deficient found no alterations in these cells' biogeography in the zebrafish intestine and only a modest competitive disadvantage in chitin-binding and colonization fitness when competed against the wild-type strain. These results argue against the model of GbpA being a secreted adhesin that binds simultaneously to bacterial cells and GlcNAc, and instead suggests that GbpA is part of a bacterial GlcNAc utilization program. We show that the host proliferative response to GbpA occurs in the absence of bacteria upon exposure of germ-free zebrafish to preparations of native GbpA secreted from either or or recombinant GbpA. Furthermore, domain 1 of GbpA, containing the predicted LPMO activity, is sufficient to stimulate intestinal epithelial proliferation. We propose that intestinal epithelial tissues upregulate their rates of renewal in response to secreted bacterial GbpA proteins as an adaptive strategy for coexisting with bacteria that can degrade glycan constituents of the protective intestinal lining.
Topics: Animals; Mice; Carrier Proteins; Zebrafish; Aeromonas; Gastrointestinal Microbiome; Intestines; Cell Proliferation; Bacterial Proteins; Chitin
PubMed: 36859771
DOI: 10.1080/19490976.2023.2183686