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PLoS Biology Aug 2023Antibiotic resistance is a continuously increasing concern for public healthcare. Understanding resistance mechanisms and their emergence is crucial for the development...
Antibiotic resistance is a continuously increasing concern for public healthcare. Understanding resistance mechanisms and their emergence is crucial for the development of new antibiotics and their effective use. The peptide antibiotic albicidin is such a promising candidate that, as a gyrase poison, shows bactericidal activity against a wide range of gram-positive and gram-negative bacteria. Here, we report the discovery of a gene amplification-based mechanism that imparts an up to 1000-fold increase in resistance levels against albicidin. RNA sequencing and proteomics data show that this novel mechanism protects Salmonella Typhimurium and Escherichia coli by increasing the copy number of STM3175 (YgiV), a transcription regulator with a GyrI-like small molecule binding domain that traps albicidin with high affinity. X-ray crystallography and molecular docking reveal a new conserved motif in the binding groove of the GyrI-like domain that can interact with aromatic building blocks of albicidin. Phylogenetic studies suggest that this resistance mechanism is ubiquitous in gram-negative bacteria, and our experiments confirm that STM3175 homologs can confer resistance in pathogens such as Vibrio vulnificus and Pseudomonas aeruginosa.
Topics: Gene Amplification; Anti-Bacterial Agents; Molecular Docking Simulation; Phylogeny; Gram-Negative Bacteria; Gram-Positive Bacteria
PubMed: 37561817
DOI: 10.1371/journal.pbio.3002186 -
Scientific Reports Aug 2023Grouper culture has been expanding in Malaysia due to the huge demand locally and globally. However, due to infectious diseases such as vibriosis, the fish mortality...
Oleic acid as potential immunostimulant in metabolism pathways of hybrid grouper fingerlings (Epinephelus fuscoguttatus × Epinephelus lanceolatus) infected with Vibrio vulnificus.
Grouper culture has been expanding in Malaysia due to the huge demand locally and globally. However, due to infectious diseases such as vibriosis, the fish mortality rate increased, which has affected the production of grouper. Therefore, this study focuses on the metabolic profiling of surviving infected grouper fed with different formulations of fatty acid diets that acted as immunostimulants for the fish to achieve desirable growth and health performance. After a six-week feeding trial and one-week post-bacterial challenge, the surviving infected grouper was sampled for GC-MS analysis. For metabolite extraction, a methanol/chloroform/water (2:2:1.8) extraction method was applied to the immune organs (spleen and liver) of surviving infected grouper. The distribution patterns of metabolites between experimental groups were then analyzed using a metabolomics platform. A total of 50 and 81 metabolites were putatively identified from the spleen and liver samples, respectively. Our further analysis identified glycine, serine, and threonine metabolism, and alanine, aspartate and glutamate metabolism had the most impacted pathways, respectively, in spleen and liver samples from surviving infected grouper. The metabolites that were highly abundant in the spleen found in these pathways were glycine (20.9%), l-threonine (1.0%) and l-serine (0.8%). Meanwhile, in the liver l-glutamine (1.8%) and aspartic acid (0.6%) were found to be highly abundant. Interestingly, among the fish diet groups, grouper fed with oleic acid diet produced more metabolites with a higher percent area compared to the control diets. The results obtained from this study elucidate the use of oleic acid as an immunostimulant in fish feed formulation affects more various immune-related metabolites than other formulated feed diets for vibriosis infected grouper.
Topics: Animals; Bass; Vibrio vulnificus; Oleic Acid; Diet; Vibrio Infections; Fish Diseases; Animal Feed
PubMed: 37553472
DOI: 10.1038/s41598-023-40096-7 -
Marine Pollution Bulletin Sep 2023Waterborne pathogenic bacteria, including faecal indicator bacteria and potentially pathogenic Vibrio, are a global concern for diseases transmitted through water. A... (Review)
Review
Waterborne pathogenic bacteria, including faecal indicator bacteria and potentially pathogenic Vibrio, are a global concern for diseases transmitted through water. A systematic review was conducted to analyse publications that investigated these bacteria in relation to macrophytes (seagrasses and macroalgae) in coastal marine environments. The highest quantities of FIB were found on brown algae and seagrasses, and the highest quantities of Vibrio bacteria were on red algae. The most extensively studied macrophyte group was brown algae, green algae were the least researched. Macrophyte wrack was found to favor the presence of FIB, but there is a lack of information about Vibrio quantities in this environment. To understand the role of Vibrio bacteria that are pathogenic to humans, molecular methods complementary to cultivation methods should be used. Further research is needed to understand the underlying mechanisms of FIB and potentially pathogenic Vibrio with macrophytes and their microbiome in the coastal marine environment.
Topics: Humans; Vibrio parahaemolyticus; Environment; Ecosystem
PubMed: 37523954
DOI: 10.1016/j.marpolbul.2023.115325 -
Frontiers in Microbiology 2023Detecting and identifying the origins of foodborne pathogen outbreaks is a challenging. The Next-Generation Sequencing (NGS) panel method offers a potential solution by...
Detecting and identifying the origins of foodborne pathogen outbreaks is a challenging. The Next-Generation Sequencing (NGS) panel method offers a potential solution by enabling efficient screening and identification of various bacteria in one reaction. In this study, new NGS panel primer sets that target 18 specific virulence factor genes from six target pathogens (, , , , , and ) were developed and optimized. The primer sets were validated for specificity and selectivity through singleplex PCR, confirming the expected amplicon size. Crosscheck and multiplex PCR showed no interference in the primer set or pathogenic DNA mixture. The NGS panel analysis of spiked water samples detected all 18 target genes in a single reaction, with pathogen concentrations ranging from 10 to 10 colony-forming units (CFUs) per target pathogen. Notably, the total sequence read counts from the virulence factor genes showed a positive association with the CFUs per target pathogen. However, the method exhibited relatively low sensitivity and occasional false positive results at low pathogen concentrations of 10 CFUs. To validate the detection and identification results, two sets of quantitative real-time PCR (qPCR) analyses were independently performed on the same spiked water samples, yielding almost the same efficiency and specificity compared to the NGS panel analysis. Comparative statistical analysis and Spearman correlation analysis further supported the similarity of the results by showing a negative association between the NGS panel sequence read counts and qPCR cycle threshold (Ct) values. To enhance NGS panel analysis for better detection, optimization of primer sets and real-time NGS sequencing technology are essential. Nonetheless, this study provides valuable insights into applying NGS panel analysis for multiple foodborne pathogen detection, emphasizing its potential in ensuring food safety.
PubMed: 37520347
DOI: 10.3389/fmicb.2023.1179934 -
Vaccines Jul 2023Intracranial sarcoma is an uncommon aggressive cancer with a poor prognosis and a high recurrence rate. Although postoperative adjuvant radiotherapy (RT) is the most...
Intracranial sarcoma is an uncommon aggressive cancer with a poor prognosis and a high recurrence rate. Although postoperative adjuvant radiotherapy (RT) is the most recommended treatment strategy, it does not significantly improve survival rates. In this study, we used an attenuated strain engineered to secrete Vibrio vulnificus flagellin B (SLpFlaB) as an immunotherapy to assist with the antitumor effects of RT on intracranial sarcoma. In vitro, the expression of γH2AX and cleaved caspase-3 was analyzed by Western blot. In vivo detection of SLpFlaB colonization time in tumors was measured using an in vivo imaging system (IVIS). Tumor growth delay and elimination were demonstrated in an intracranial mouse model, and the distribution of macrophages, M1 macrophages, and CD8 cells after treatment was measured using FACS analysis. Our findings in vitro suggest that combination therapy increases S-180 radiosensitivity, the expression of DNA double-strand breaks, and programmed cell death. In vivo, combination treatment causes intracranial sarcoma to be eliminated without tumor recurrence and redistribution of immune cells in the brain, with data showing the enhanced migration and infiltration of CD8 T cells and macrophages, and an increased proportion of M1 macrophage polarization. Compared to RT alone, the combination therapy enhanced the radiosensitivity of S-180 cells, promoted the recruitment of immune cells at the tumor site, and prevented tumor recurrence. This combination therapy may provide a new strategy for treating intracranial sarcomas.
PubMed: 37515090
DOI: 10.3390/vaccines11071275 -
Internal Medicine Journal Jan 2024Vibrio species bloodstream infections have been associated with significant mortality and morbidity. Limited information is available regarding the epidemiology of...
BACKGROUND
Vibrio species bloodstream infections have been associated with significant mortality and morbidity. Limited information is available regarding the epidemiology of bloodstream infections because of Vibrio species in the Australian context.
AIMS
The objective of this study was to define the incidence and risk factors for developing Vibrio species bloodstream infections and compare differences between different species.
METHODS
All patients with Vibrio spp. isolated from positive blood cultures between 1 January 2000 and 31 December 2019 were identified by the state-wide Pathology Queensland laboratory. Demographics, clinical foci of infections and comorbid conditions were collected in addition to antimicrobial susceptibility results.
RESULTS
About 100 cases were identified between 2000 and 2019 with an incidence of 1.2 cases/1 million person-years. Seasonal and geographical variation occurred with the highest incidence in the summer months and in the tropical north. Increasing age, male sex and multiple comorbidities were identified as risk factors. Vibrio vulnificus was isolated most frequently and associated with the most severe disease. Overall case fatality was 19%.
CONCLUSIONS
There is potential for increasing cases of Vibrio species infections globally with ageing populations and climate change. Ongoing clinical awareness is required to ensure optimal patient outcomes.
Topics: Humans; Male; Queensland; Australia; Vibrio; Vibrio Infections; Sepsis
PubMed: 37497569
DOI: 10.1111/imj.16187 -
Fish & Shellfish Immunology Sep 2023C-type lectins, one of the pattern recognition receptors (PRRs), play significant roles in innate immune responses through binding to the pathogen-associated molecular...
C-type lectins, one of the pattern recognition receptors (PRRs), play significant roles in innate immune responses through binding to the pathogen-associated molecular patterns (PAMPs) presented on surfaces of microorganisms. Here, a novel C-type lectin (named as MaCTL) from blunt snout bream (Megalobrama amblycephala) was cloned and characterized. The open reading frame (ORF) of MaCTL is 573 bp long encoding a putative protein of 190 amino acids (aa), which contains a typical feature of signal peptide at 1-23 aa, a characteristic CRD domain at 45-178 aa and a WND/EPN motif that is required for carbohydrates-binding specificity. Phylogenetic analysis indicated that MaCTL is a novel member of CTL family and possessed the highest similarity to that of grass carp (92.11%). The qRT-PCR analysis revealed that MaCTL expressed widely in all examined normal tissues, including heart, liver, spleen, kidney, head-kidney, gill, intestine and muscle, with the higher expression in the spleen, liver and muscle. The expression of MaCTL in spleen was significantly elevated, peaking at 9 h and 6 h after LPS stimulation and Aeromonas hydrophila challenge, respectively, suggesting its association with involvement in innate immune response. The recombinant MaCTL protein (rMaCTL) agglutinated markedly both Gram-positive (Staphylococcus aureus) and Gram-negative bacteria, including Escherichia coli, Vibrio anguillarum, Vibrio vulnificus and Aeromonas hydrophila, in a Ca-dependent manner. Meanwhile, rMaCTL showed the binding effects on the five bacteria and four carbohydrates, such as glucose, surose, LPS and PGN. Moreover, rMaCTL could remarkably inhibit the growth of three types of bacteria in vitro. Overall, the results obtained above demonstrated firmly that MaCTL binds to carbohydrates on the surface of diverse pathogens as a PRR and elicits antimicrobial responses, which shed new light on a better understanding of antibacterial functions of CTLs in teleost fish.
Topics: Animals; Lectins, C-Type; Cyprinidae; Phylogeny; Lipopolysaccharides; Amino Acid Sequence; Fish Proteins; Base Sequence; Immunity, Innate; Cypriniformes; Recombinant Proteins; Aeromonas hydrophila
PubMed: 37482206
DOI: 10.1016/j.fsi.2023.108966 -
The Veterinary Quarterly Dec 2023an opportunistic human pathogen native to marine/estuarine environment, is one of the leading causes of death due to seafood consumption and exposure of wounds to...
an opportunistic human pathogen native to marine/estuarine environment, is one of the leading causes of death due to seafood consumption and exposure of wounds to seawater worldwide. The present study involves the whole genome sequence analysis of an environmental strain of (clinical genotype) isolated from seafood along the Mangaluru coast of India. The sequenced genome data was subjected to analysis of phylogeny, virulence genes, antimicrobial resistance determinants, and secretary proteins using suitable bioinformatics tools. The sequenced isolate had an overall genome length of 4.8 Mb and GC content of 46% with 4400 coding DNA sequences. The sequenced strain belongs to a new sequence type (Multilocus sequence typing) and was also found to branch with a phylogenetic lineage that groups the most infectious strains of . The seafood isolate had complete genes involved in conferring serum resistance yet showed limited serum resistance. The study identified several genes against the antibiotics that are commonly used in their treatment, highlighting the need for alternative treatments. Also, the secretory protein analysis revealed genes associated with major pathways like ABC transporters, two-component systems, quorum sensing, biofilm formation, cationic antimicrobial peptide (CAMP) resistance, and others that play a critical role in the pathogenesis of the . To the best of our knowledge, this is the first report of a detailed analysis of the genomic information of a isolated from the Indian subcontinent and provides evidence that raises public health concerns about the safety of seafood.
Topics: Humans; Animals; Vibrio vulnificus; Virulence; Phylogeny; Genotype; Seafood
PubMed: 37478018
DOI: 10.1080/01652176.2023.2240389 -
Frontiers in Microbiology 2023is a gram-negative, opportunistic pathogen common to warm waters worldwide. Human infection is rare and typically affects those residing in coastal areas during the...
BACKGROUND
is a gram-negative, opportunistic pathogen common to warm waters worldwide. Human infection is rare and typically affects those residing in coastal areas during the summer months, but it causes rapid deterioration and is fatal.
METHODS
The medical records of six patients with sepsis caused by infection who were treated at the First Affiliated Hospital of Ningbo University from 2020 to 2022 were retrospectively reviewed. The patient demographics, clinical symptoms, laboratory test results, treatments, and outcomes are summarized.
RESULTS
infection was confirmed by blood or pus culture, 16S ribosomal DNA sequencing, and metagenomic next-generation sequencing. All six patients were male with pre-existing liver diseases and two reported consuming seafood before the onset of symptoms. Of the six patients, four succumbed to the disease, two recovered, and one underwent leg amputation.
CONCLUSION
infection progresses rapidly and is highly fatal, thus prompt and aggressive treatment is necessary. infection should be considered in older (>40 years) patients with a history of liver disease and recent consumption of seafood or exposure to seawater, especially those residing in coastal areas during the summer months.
PubMed: 37469427
DOI: 10.3389/fmicb.2023.1220526 -
Journal of Microbiological Methods Aug 2023Rapid and accurate detection of bacterial pathogens is critical in controlling disease outbreaks affecting farmed fish. The present study aimed to develop a novel...
Rapid and accurate detection of bacterial pathogens is critical in controlling disease outbreaks affecting farmed fish. The present study aimed to develop a novel serological diagnostic approach using nano‑silver based Enzyme-linked immunosorbent assay (ELISA) for speedy detection of Aeromonas veronii infections in Nile tilapia. A. veronii isolates used in ELISA assays were recovered from moribund Nile tilapia during a disease outbreak in a private fish farm in Egypt. A. veronii isolates were identified based on alignment analysis of the gyrB and 16S rRNA gene sequences. A. veronii antisera used in ELISA assays were prepared in tilapia, and the bacterial antigens were formalin-killed. The cut-off values were 0.46 and 0.48 in traditional and nano-based ELISA. There were no cross-reactions with bacterial isolates (Aeromonas hydrophila, Aeromonas caviae, Aeromonas sobria, Pseudomonas fluorescens, and Vibrio vulnificus). The lowest antigen concentration that produced positive results after checkerboard titration in indirect-ELISA (i-ELISA) and dot ELISA was 15 μg and 250 ng of prepared antigen, respectively. Nano-ELISA and nano-based dot-ELISA antigen concentration was 10 μg and 100 ng, respectively. Sera concentration was 1:100 in indirect-ELISA and dot-ELISA, while it was 1:50 in nano-based ELISA and nano dot-ELISA. The i-ELISA successfully detected anti-Aeromonas IgG antibodies with 83.33% sensitivity and 66.67% specificity, while in the dot-ELISA, the sensitivity and specificity were 83.33% and 100%, respectively. Nano dot-ELISA had 100% sensitivity, specificity, and accuracy. Nano dot-ELISA assays have higher specificity, sensitivity, and accuracy than traditional ELISAs in detecting A. veronii. Further studies are needed to develop a rapid test kit for on-site field diagnosis.
Topics: Animals; Aeromonas veronii; RNA, Ribosomal, 16S; Silver; Aeromonas hydrophila; Enzyme-Linked Immunosorbent Assay; Gram-Negative Bacterial Infections; Fish Diseases
PubMed: 37451347
DOI: 10.1016/j.mimet.2023.106782