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BMC Genomics Feb 2024DNA N6-methyladenosine (6mA), as an important epigenetic modification, widely exists in bacterial genomes and participates in the regulation of toxicity, antibiotic...
BACKGROUND
DNA N6-methyladenosine (6mA), as an important epigenetic modification, widely exists in bacterial genomes and participates in the regulation of toxicity, antibiotic resistance, and antioxidant. With the continuous development of sequencing technology, more 6mA sites have been identified in bacterial genomes, but few studies have focused on the distribution characteristics of 6mA at the whole-genome level and its association with gene expression and function.
RESULTS
This study conducted an in-depth analysis of the 6mA in the genomes of two pathogenic bacteria, Aeromonas veronii and Helicobacter pylori. The results showed that the 6mA was widely distributed in both strains. In A. veronii, 6mA sites were enriched at 3' end of protein-coding genes, exhibiting a certain inhibitory effect on gene expression. Genes with low 6mA density were associated with cell motility. While in H. pylori, 6mA sites were enriched at 5' end of protein-coding genes, potentially enhancing gene expression. Genes with low 6mA density were closely related to defense mechanism.
CONCLUSIONS
This study elucidated the distribution characteristics of 6mA in A. veronii and H. pylori, highlighting the effects of 6mA on gene expression and function. These findings provide valuable insights into the epigenetic regulation and functional characteristics of A. veronii and H. pylori.
Topics: Helicobacter pylori; Epigenesis, Genetic; Aeromonas veronii; DNA; Adenosine; DNA Methylation
PubMed: 38331763
DOI: 10.1186/s12864-024-10074-y -
The Journal of Antimicrobial... Mar 2024To characterize the genetic environments of ESBL gene blaVEB-1 in mcr-positive Aeromonas strains from raw meat in China.
OBJECTIVES
To characterize the genetic environments of ESBL gene blaVEB-1 in mcr-positive Aeromonas strains from raw meat in China.
METHODS
Whole genomes of Aeromonas strains were sequenced using the Illumina or Nanopore platforms. Genetic environments of blaVEB-1 were analysed using the BLAST program.
RESULTS
The blaVEB-1 gene was detected in five Aeromonas strains carrying the mcr-7-like gene. WGS revealed that all blaVEB-1 genes were located on Aeromonas chromosome, and were carried by two novel different genomic islands named Aeromonas veronii genomic islands AveGI1 and AveGI2, as well as one transposon named Tn7690. AveGI1 is a new member of the Salmonella genomic island 1 family, incorporated into the 3'-end of mnmE (trmE). AveGI2 is a novel genomic island that has a size of 23 180 bp and is incorporated into the 3'-end of syd. The MDR regions of AveGI1 and AveGI2 are two different class 1 integrons containing 10 and five resistance genes, respectively. Tn7690 is a Tn1722 derivative containing In4-type integron and Tn5393, which harbours 10 resistance genes and integrates into different positions on the chromosomes of three strains with the capacity for mobility.
CONCLUSIONS
We report chromosomally located novel MDR genomic islands and transposon that carry blaVEB-1 in mcr-positive Aeromonas strains. These genetic elements may mediate the spread of blaVEB-1 in Aeromonas, and may also evolve by capturing new antimicrobial resistance genes or other mobile genetic elements.
Topics: Aeromonas; Genomic Islands; China; Integrons; Meat
PubMed: 38319867
DOI: 10.1093/jac/dkae031 -
Microorganisms Jan 2024This study aimed to characterize 300 spp. strains isolated from 123 ornamental fish of 32 different species presenting with septicemia, skin lesions, and/or eye...
This study aimed to characterize 300 spp. strains isolated from 123 ornamental fish of 32 different species presenting with septicemia, skin lesions, and/or eye lesions. Within the 300 strains, 53.0% were identified as , 41.3% as , and 5.7% as . Among the six virulence genes investigated, the most frequent were (90.3%) and (79.3%). More than 50% of strains were positive for all the studied genes. A total of 30 virulence profiles were identified, with the five main profiles identified comprising 75% of strains. Only five strains were negative for all genes and were identified as and . The antimicrobial susceptibility profile was performed for 234 strains, with sulfonamides presenting more than 50% of the resistance rates. Susceptibility was observed mainly for cephalosporins, aminoglycosides, chloramphenicol and piperacillin-tazobactam. Multidrug resistance was detected in 82.5% of the studied strains, including with 100% multidrug resistance, and with 90.9% multidrug resistance. The SE-AFLP analysis resulted in 66 genotypes of , 118 genotypes of , and 14 genotypes of , demonstrating the greater heterogeneity of and A. . However, no direct correlation was observed between the genotypes and the strains' origins or virulence and resistance profiles.
PubMed: 38258002
DOI: 10.3390/microorganisms12010176 -
Animals : An Open Access Journal From... Jan 2024The ubiquitous Gram-negative bacterial pathogen () can easily cause inflammatory reactions in aquatic organisms, resulting in high mortality and huge economic losses....
The ubiquitous Gram-negative bacterial pathogen () can easily cause inflammatory reactions in aquatic organisms, resulting in high mortality and huge economic losses. MicroRNAs (miRNAs) participate in immune regulation and have certain conserved properties. MiRNAs are involved in the immune responses of a variety of teleost fish infected with bacteria, whereas there is no related report in silver carp (). Therefore, we identified the expression profiles of miRNA in silver carp stimulated by and LPS. Among them, the quantity of differentially expressed miRNAs (DEmiRNAs) obtained in the silver carp challenge group was 73 () and 90 (LPS). The GO enrichment and analysis of KEGG pathways have shown that the predicted target genes are mainly associated with lipid metabolism and the immune response in silver carp. This indicates the possibility that miRNAs play a role in regulating immune-related pathways. In addition, a total of eight DEmiRNAs validated the accuracy of the sequencing result via quantitative real-time PCR (qRT-PCR). Finally, we selected the silver carp head kidney macrophage cells (HKCs) as model cells and proved that miR-30b-5p can regulate the inflammatory response in silver carp HKCs. This study lays the foundation for exploring miRNA regulation in silver carp during pathogenic bacterial infection. In addition, it provides a reference for the future development of non-coding RNA antibacterial drugs.
PubMed: 38254454
DOI: 10.3390/ani14020285 -
Fish & Shellfish Immunology Mar 2024A mucoadhesive chitosan polymer-based nanoplatform has been increasingly recognized as an effective mucosal vaccine delivery system for fish. The present study aimed to...
Systemic and mucosal immune responses in red tilapia (Oreochromis sp.) following immersion vaccination with a chitosan polymer-based nanovaccine against Aeromonas veronii.
A mucoadhesive chitosan polymer-based nanoplatform has been increasingly recognized as an effective mucosal vaccine delivery system for fish. The present study aimed to investigate the effectiveness of immersion vaccination with a chitosan polymer-based nanovaccine to elicit an immune response in serum and mucus of red tilapia and evaluate its protective efficacy after immersion challenge with a heterogenous strain of Aeromonas veronii UDRT09. Six hundred red tilapia (22 ± 1.8 g) were randomly allocated into four experimental groups: control, empty-polymeric nanoparticle (PC), formalin-killed vaccine (FKV), and chitosan polymer-based nanovaccine (CS-NV) in triplicate. The specific IgM antibody levels and their bactericidal activity were assessed in serum and mucus for 28 days after immersion vaccination and followed by immersion challenge with A. veronii. The immersion vaccine was found to be safe for red tilapia, with no mortalities occurring during the vaccination procedure. The specific IgM antibody levels and bactericidal activity against A. veronii in both serum and mucus were significantly higher in red tilapia vaccinated with CS-NV compared to the FKV and control groups at all time points. Furthermore, the serum lysozyme activity, ACH, and total Ig levels demonstrated a significant elevation in the groups vaccinated with CS-NV compared to the FKV and control groups. Importantly, the Relative Percentage Survival (RPS) value of the CS-NV group (71 %) was significantly higher than that of the FKV (15.12 %) and PC (2.33 %) groups, respectively. This indicates that the chitosan polymer-based nanovaccine platform is an effective delivery system for the immersion vaccination of tilapia.
Topics: Animals; Tilapia; Chitosan; Nanovaccines; Aeromonas veronii; Immunity, Mucosal; Polymers; Immersion; Fish Diseases; Cichlids; Vaccination; Vaccines, Inactivated; Immunoglobulin M
PubMed: 38246266
DOI: 10.1016/j.fsi.2024.109383 -
Developmental and Comparative Immunology Apr 2024Aeromonas veronii is an opportunistic pathogen that causes diseases in aquatic animals, but its key virulence factors remain unclear. We screened the gene tolC with...
Aeromonas veronii is an opportunistic pathogen that causes diseases in aquatic animals, but its key virulence factors remain unclear. We screened the gene tolC with significantly different expression levels in the two isolates, A. veronii GL2 (higher virulence) and A. veronii FO1 (lower virulence). Therefore, we constructed mutant strain ΔtolC and analyzed its immunological properties. ΔtolC exhibited the reduced ability of biofilms formation, inhibited envelope stress response mediated by several antibiotics except cefuroxime, implying the ability to evade host immunity might be restrained. Challenge tests showed that the LD of ΔtolC was 10.89-fold than that of GL2. Enzymatic activities of ΔtolC group were significantly lower and peak time was delayed to 12 h, as demonstrated by qRT-PCR results. Histopathological examination displayed that the degree of tissue damage in ΔtolC group was alleviated. The results show that tolC is an important virulence factor of A. veronii, which provides references for live-attenuated vaccine.
Topics: Animals; Aeromonas veronii; Virulence; Virulence Factors; Bivalvia; Fresh Water; Immunity; Gram-Negative Bacterial Infections; Fish Diseases; Aeromonas
PubMed: 38224762
DOI: 10.1016/j.dci.2024.105137 -
BMC Veterinary Research Jan 2024Aeromonas species are one of the most important etiologies of diseases in fish farms, leading to clinical manifestation and mortality and are associated with public...
BACKGROUND
Aeromonas species are one of the most important etiologies of diseases in fish farms, leading to clinical manifestation and mortality and are associated with public health risks. This study aimed to investigate the prevalence, phenotypic and molecular characteristics of Aeromonas species isolated from farmed Clarias gariepinus using 16 S rRNA sequencing. Additionally, their antibiogram and multiple antibiotic resistance index were determined using a disc diffusion test.
RESULTS
A total of 230 Aeromonas strains were isolated from Clarias gariepinus with 40.9% obtained from diseased fish, and 25% isolated from apparently healthy ones. Five different species including Aeromonas caviae, Aeromonas veronii, Aeromonas hydrophila, Aeromonas dhakensis and Aeromonas enteropelogenes were fully identified and genetically characterized. Based on the available literature, this is the first report of Aeromonas enteropelogenes from the study area. The phylogenetic analysis showed genetic heterogeneity and distance within the species and the reference strains. The multiple resistant Aeromonas species were susceptible to ciprofloxacin, gentamycin, and florfenicol. The Aeromonas species' multiple antibiotic resistance index values varied between 0.20 and 0.80 and were isolated from the farms where antibiotics were intensively used.
CONCLUSIONS
The diversity of multidrug-resistant Aeromonas species isolated from fish farms is a major threat to fish production giving us more understanding of epidemiology and the multidrug Aeromonas species with a MAR index of greater than 0.2 were isolated from farms where antibiotic use was widespread. As a result, a considerably increased danger of multiple antibiotic resistance spreading to the fish culture environment may impact aquaculture production. Hence there is a need for appropriate and monitored drug usage.
Topics: Animals; Catfishes; Phylogeny; Aeromonas; Drug Resistance, Microbial; Anti-Bacterial Agents
PubMed: 38184574
DOI: 10.1186/s12917-023-03860-5 -
PloS One 2024The presence of carbapenem-resistant bacteria and carbapenem resistance genes (CRGs) in livestock is increasing. To evaluate the presence of carbapenemase-producing...
The presence of carbapenem-resistant bacteria and carbapenem resistance genes (CRGs) in livestock is increasing. To evaluate the presence of carbapenemase-producing Enterobacteriaceae (CPE) and the main CRGs along swine food chains of the Marche Region (Central Italy), samples of faeces, feed, and animal-food derived products were collected from seven small/medium, medium, and large-scale pig farms. A total of 191 samples were analysed using a culture-dependent method, with the aim of isolating CPE. Isolates were analysed for their resistance to carbapenems using a modified Hodge test and the microdilution method for the minimum inhibitory concentration (MIC) determination. Moreover, the extraction of microbial DNA from each sample was performed to directly detect selected CRGs via qPCR. Among the 164 presumptive resistant isolates, only one strain from a liver sample, identified as Aeromonas veronii, had an ertapenem MIC of 256 μg/mL and carried a carbapenemase- (cphA) and a β-lactamase- (blaOXA-12) encoding genes. A low incidence of CRGs was found; only nine and four faecal samples tested positive for blaNDM-1 and blaOXA-48, respectively. Overall, the importance of monitoring CPE and CRGs in livestock and their food chains should be stressed to control all potential non-human CPE and CRGs reservoirs and to determine safety levels for human health.
Topics: Animals; Swine; Food Chain; Bacteria; Carbapenem-Resistant Enterobacteriaceae; Carbapenems; Italy; Livestock
PubMed: 38181018
DOI: 10.1371/journal.pone.0296098 -
MBio Feb 2024Many pathogenic Gram-negative bacteria use repeats-in-toxin adhesins for colonization and biofilm formation. In the cholera agent , flagellar-regulated hemagglutinin A...
Many pathogenic Gram-negative bacteria use repeats-in-toxin adhesins for colonization and biofilm formation. In the cholera agent , flagellar-regulated hemagglutinin A (FrhA) enables these functions. Using bioinformatic analysis, a sugar-binding domain was identified in FrhA adjacent to a domain of unknown function. AlphaFold2 indicated the boundaries of both domains to be slightly shorter than previously predicted and assisted in the recognition of the unknown domain as a split immunoglobulin-like fold that can assist in projecting the sugar-binding domain toward its target. The AlphaFold2-predicted structure is in excellent agreement with the molecular envelope obtained from small-angle X-ray scattering analysis of a recombinant construct spanning the sugar-binding and unknown domains. This two-domain construct was probed by glycan micro-array screening and showed binding to mammalian fucosylated glycans, some of which are characteristic erythrocyte markers and intestinal cell epitopes. Isothermal titration calorimetry further showed the construct-bound l-fucose with a of 21 µM. Strikingly, this recombinant protein construct bound and lysed erythrocytes in a concentration-dependent manner, and its hemolytic activity was blocked by the addition of l-fucose. A protein ortholog construct from was also produced and showed a similar glycan-binding pattern, binding affinity, erythrocyte-binding, and hemolytic activities. As demonstrated here with Hep-2 cells, fucose-based inhibitors of this sugar-binding domain can potentially be developed to block colonization by and other pathogenic bacteria that share this adhesin domain.IMPORTANCEThe bacterium, , which causes cholera, uses an adhesion protein to stick to human cells and begin the infection process. One part of this adhesin protein binds to a particular sugar, fucose, on the surface of the target cells. This binding can lead to colonization and killing of the cells by the bacteria. Adding l-fucose to the bacteria before they bind to the human cells can prevent attachment and has promise as a preventative drug to protect against cholera.
Topics: Animals; Humans; Vibrio cholerae; Cholera; Aeromonas veronii; Fucose; Adhesins, Bacterial; Polysaccharides; Toxins, Biological; Sugars; Mammals
PubMed: 38171003
DOI: 10.1128/mbio.02291-23 -
Open Forum Infectious Diseases Dec 2023The genus is increasingly implicated in human infections, but knowledge of its clinical characteristics and antimicrobial resistance profiles has been limited owing to...
BACKGROUND
The genus is increasingly implicated in human infections, but knowledge of its clinical characteristics and antimicrobial resistance profiles has been limited owing to its complex taxonomy.
METHODS
We conducted a multicenter prospective cohort study of patients with infections at hospitals across Japan. Patients were eligible for inclusion if they had an spp. strain in a clinical culture and were considered infected at the culture site. Clinical data were collected, and isolates underwent susceptibility testing and whole-genome sequencing.
RESULTS
A total of 144 patients were included. Hepatobiliary infection accounted for a majority of infections (73% [105 of 144]), which mostly occurred in elderly patients with comorbid conditions, including hepatobiliary complications. The all-cause 30-day mortality rate was 10.0% (95% confidence interval, 4.9%-14.8%). By whole-genome sequencing, 141 strains (98%) belonged to 4 species, , , and with significant intraspecies diversity. was predominant in all infection sites except skin and soft tissue, for which was the prevailing species. The genes encoding chromosomally mediated class B, C, and D β-lactamases were harbored by 92%-100% of the isolates in a species-specific manner, but they often lacked association with resistance phenotypes. The activity of cefepime was reliable. All isolates of and carried an like colistin resistance gene and showed reduced susceptibility to colistin.
CONCLUSIONS
Hepatobiliary tract was the most common infection site of spp., with being the dominant causative species. The resistance genotype and phenotype were often incongruent for β-lactam agents.
PubMed: 38156048
DOI: 10.1093/ofid/ofad587