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Journal of Global Antimicrobial... Dec 2023
Topics: Genomic Islands; Salmonella; beta-Lactamases
PubMed: 37748579
DOI: 10.1016/j.jgar.2023.09.014 -
Cureus Jul 2023is a pathogenic Gram-negative bacillus typically resulting in gastroenteritis in humans. It has recently been identified as a growing concern for public health. The...
is a pathogenic Gram-negative bacillus typically resulting in gastroenteritis in humans. It has recently been identified as a growing concern for public health. The case presented is an uncommon case of causing bacteremia, as well as hemorrhagic skin lesions. Other reported cases have also highlighted unexpected manifestations, such as cerebritis, bacterial peritonitis, and otitis externa. These atypical presentations can happen in immunocompromised individuals. There are no established guidelines currently for the treatment of bacteremia. This case presents bacteremia that improved with doxycycline without the need for incision and drainage of the patient's lower extremity lesions.
PubMed: 37521591
DOI: 10.7759/cureus.42612 -
Journal of Tropical Medicine 2023The noncholera spp. which cause vibriosis are abundantly found in our water ecosystem. These bacteria could negatively affect both humans and animals. To date, there is...
BACKGROUND
The noncholera spp. which cause vibriosis are abundantly found in our water ecosystem. These bacteria could negatively affect both humans and animals. To date, there is a paucity of information available on the existence and pathogenicity of this particular noncholera spp. in Malaysia in comparison to their counterpart, .
METHODS
In this study, we extracted retrospective data from Malaysian surveillance database. Analysis was carried out using WHONET software focusing noncholera spp. including , , , , (), , , and .
RESULTS
Here, we report the first distribution and prevalence of these species isolated in Malaysia together with the antibiotic sensitivity profile based on the species. We found that is the predominant species isolated in Malaysia. Noticeably, across the study period, is becoming more prevalent, as compared to . In addition, this study also reports the first isolation of pathogenic from stool in Malaysia.
CONCLUSION
These data represent an important step toward understanding the potential emergence of noncholera spp. outbreaks.
PubMed: 37274080
DOI: 10.1155/2023/2716789 -
Foods (Basel, Switzerland) Mar 2023Previous research has shown that freshwater edible fish imported into Australia are not compliant with Australian importation guidelines and as a result may be high risk...
Previous research has shown that freshwater edible fish imported into Australia are not compliant with Australian importation guidelines and as a result may be high risk for bacterial contamination. In the present study, the outer surface of imported freshwater fish were swabbed, cultured, confirmatory tests performed and antimicrobial patterns investigated. Channidae fish (Sp. A/n = 66) were contaminated with zoonotic sp./ (n = 1/66) and other bacteria implicated in cases of opportunistic human infection, these being sp. (including . and (n = 34/66)); sp. (n = 32/66); (n = 27/66) and (n = 3/66). Pangasiidae fish (Species B/n = 47) were contaminated with zoonotic (n = 10/47); sp. (n = 6/47) and environmental bacteria sp. (n = 3/47). One sample was resistant to all antimicrobials tested and is considered to be Methicillin Resistant . Mud, natural diet, or vegetation identified in Sp. A fish/or packaging were significantly associated with the presence of spp. The study also showed that visibly clean fish (Sp. B) may harbour zoonotic bacteria and that certain types of bacteria are common to fish groups, preparations, and contaminants. Further investigations are required to support the development of appropriate food safety recommendations in Australia.
PubMed: 36981215
DOI: 10.3390/foods12061288 -
Microbiology Spectrum Feb 2023We found a new gene, , carried by a multidrug resistance plasmid in a clinical Vibrio furnissii isolate. QnrVF1 exhibits 44.6% to 72.5% similarity in identity with...
We found a new gene, , carried by a multidrug resistance plasmid in a clinical Vibrio furnissii isolate. QnrVF1 exhibits 44.6% to 72.5% similarity in identity with other Qnr family proteins. alleles are mainly encoded by chromosomes of V. furnissii and Vibrio fluvialis. Phylogenic analysis showed that QnrVF1 and QnrVF2 form a distinct clade in Qnr proteins. Thus, represents a new family. In addition, the gene is often flanked by the mobile element IS. Thus, it is likely that is mobilized by IS from chromosome to plasmid in V. furnissii. Quinolones are widely used drugs. Bacteria contain a quinolone resistance gene, which mediates resistance to quinolones. Currently, seven families of Qnr proteins, QnrVC, QnrA, QnrB, QnrC, QnrD, QnrE, and QnrS, have been identified. However, it is unclear whether there are any other families. In this study, we identified a new family, . We found many V. furnissii and V. fluvialis strains that possess chromosomal alleles, suggesting that V. furnissii and V. fluvialis are the reservoirs of . We also found that QnrVF1 confers low-level resistance to quinolones. IS may facilitate the spread of . The emergence and spread of may pose a considerable threat to public health.
Topics: Anti-Bacterial Agents; Drug Resistance, Bacterial; Quinolones; Plasmids; Microbial Sensitivity Tests
PubMed: 36656040
DOI: 10.1128/spectrum.01934-22 -
Microbiology Spectrum Feb 2023Vibrio cholerae can utilize a type VI secretion system (T6SS) to increase its intra- and interspecies competition. However, much still remains to be understood about the...
Vibrio cholerae can utilize a type VI secretion system (T6SS) to increase its intra- and interspecies competition. However, much still remains to be understood about the underlying mechanism of this intraspecies competition. In this study, we isolated an environmental V. cholerae strain E1 that lacked the typical virulence factors toxin-coregulated pilus and cholera toxin and that encoded a functional T6SS. We identified an evolved VgrG3 variant with a predicted C-terminal pesticin-like domain in V. cholerae E1, designated VgrG3. Using heterologous expression, protein secretion, and peptidoglycan-degrading assays, we demonstrated that VgrG3 is a T6SS-dependent effector harboring cell wall muramidase activity and that its toxicity can be neutralized by cognate immunity protein TsiV3. Site-directed mutagenesis proved that the aspartic acid residue at position 867 is crucial for VgrG3-mediated antibacterial activity. Bioinformatic analysis showed that genes encoding VgrG3-like homologs are distributed in species, are linked with T6SS structural genes and auxiliary genes, and the gene pair of V. cholerae probably evolved from Vibrio anguillarum and Vibrio fluvialis via homologous recombination. Through a time-lapse microscopy assay, we directly determined that cells accumulating VgrG3 disrupted bacterial division, while the cells continued to increase in size until the loss of membrane potential and cell wall breakage and finally burst. The results of the competitive killing assay showed that VgrG3 contributes to V. cholerae interspecies competition. Collectively, our study revealed a novel T6SS E-I pair representing a new T6SS toxin family which allows V. cholerae to gain dominance within polymicrobial communities by T6SS. The type VI secretion system used by a broad range of Gram-negative bacteria delivers toxic proteins to target adjacent eukaryotic and prokaryotic cells. Diversification of effector proteins determines the complex bacterium-bacterium interactions and impacts the health of hosts and environmental ecosystems in which bacteria reside. This work uncovered an evolved valine-glycine repeat protein G3, carrying a C-terminal pesticin-like domain (VgrG3), which has been suggested to harbor cell wall hydrolase activity and is able to affect cell division and the integrity of cell wall structure. Pesticin-like homologs constitute a family of T6SS-associated effectors targeting bacterial peptidoglycan which are distributed in species, and genetic loci of them are linked with T6SS structural genes and auxiliary genes. T6SS-delivered VgrG3 mediated broad-spectrum antibacterial activity for several microorganisms tested, indicating that VgrG3-mediated antimicrobial activity is capable of conferring bacteria a competitive advantage over competitors in the same niches.
Topics: Type VI Secretion Systems; Vibrio cholerae; Peptidoglycan; Ecosystem; Bacterial Proteins; Anti-Bacterial Agents; Cell Wall
PubMed: 36625646
DOI: 10.1128/spectrum.04267-22 -
Iranian Journal of Microbiology Oct 2022is a Gram-negative, bacillus-shaped, curved bacterium known as an emerging pathogen. There are reports of outbreaks caused by this bacterium worldwide. Iran, especially...
BACKGROUND AND OBJECTIVES
is a Gram-negative, bacillus-shaped, curved bacterium known as an emerging pathogen. There are reports of outbreaks caused by this bacterium worldwide. Iran, especially Qom province, is an endemic region for gastrointestinal diseases caused by species. So, the aim was to isolate from clinical and environmental samples.
MATERIALS AND METHODS
During six months, 363 clinical and surface water samples were evaluated. The samples were cultured on specific media, and all incubated for 24 hours at 37°C. Suspicious colonies were evaluated by Gram staining and biochemical tests. The BD Phoenix automated microbiology system was used for the final confirmation of the isolated bacteria. Evaluation of antibiotic resistance of isolated strains was also performed according to CLSI standard.
RESULTS
Eight cases (2.2%) of , including seven from surface water samples (87.5%) and one from clinical samples (12.5%), were isolated. Based on antimicrobial susceptibility testing, all isolates were susceptible to amikacin, gentamicin, trimethoprim/sulfamethoxazole, ciprofloxacin, tetracycline, ceftazidime, and chloramphenicol. High-level resistance to ampicillin and amoxicillin/clavulanate was also observed. -infected patient had a mild fever, watery diarrhea, vomiting, nausea, and abdominal cramps that were manifested after drinking contaminated water or eating contaminated vegetables. The patient's symptoms recovered without antibiotic therapy after four days, resulting in self-limiting disease.
CONCLUSION
The current study is the first human case of infection isolated in Iran. Therefore, monitoring of water and food samples should be done routinely.
PubMed: 36531817
DOI: 10.18502/ijm.v14i5.10962 -
Journal of Dairy Science Jan 2023Composting is a common practice used for treating animal manures before they are used as organic fertilizers for crop production. Whether composting can effectively...
Composting is a common practice used for treating animal manures before they are used as organic fertilizers for crop production. Whether composting can effectively reduce microbial pathogens and antibiotic resistance genes remain poorly understood. In this study, we compared 3 different dairy manure composting methods-anaerobic fermentation (AF), static compost (SC), and organic fertilizer production (OFP)-for their effects on antibiotic-resistant bacteria, antibiotic resistance genes, and microbial community diversity in the treated manures. The 3 composting methods produced variable and distinct effects on antibiotic-resistant bacteria, zoonotic bacteria, and resistance genes, some of which were decreased and others of which showed no significant changes during composting. Particularly, SC and OFP reduced chloramphenicol resistance gene fexA and opportunistic pathogen Vibrio fluvialis, whereas AF significantly reduced tetracycline resistance gene tetB and opportunistic pathogens Enterococcus faecium and Escherichia fergusonii. The compositions of microbial communities varied significantly during the composting processes, and there were significant differences between the 3 composting methods. In all 3 composts, the dominant phyla were Firmicutes, Proteobacteria, Bacteroidetes, and Actinobacteria. Interestingly, Firmicutes, Proteobacteria, and Bacteroidetes remained stable in the entire AF process, whereas they were dominated at the beginning, decreased at the early stage of composting, and rebounded at the later stage during SC and OFP. In general, SC and OFP produced a more profound effect than AF on microbial community diversities, pathogens, and dominant species. Additionally, Enterococcus aquimarinus was isolated from AF for the first time. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States function prediction analysis indicated that the genes related to membrane transport and amino acid metabolism were abundant in the 3 composts. The metabolism of amino acids, lipids, and carbohydrates increased as composting progressed. The biosynthesis of antibiotics was enhanced after fermentation in the 3 composting methods, and the increase in the SC was the most obvious. These results reveal dynamic changes in antibiotic-resistant bacteria, antibiotic resistance genes, microbial community composition, and function succession in different dairy manure composts and provide useful information for further optimization of composting practices.
Topics: Cattle; Animals; Composting; Manure; Anti-Bacterial Agents; Phylogeny; Soil Microbiology; Drug Resistance, Microbial; Bacteria; Genes, Bacterial; Soil
PubMed: 36333143
DOI: 10.3168/jds.2022-22193 -
Gut Microbes 2022is a halophilic Gram-negative bacterium regarded as an emerging unusual enteric pathogen of increasing public health concern. Our previous work has identified two type...
is a halophilic Gram-negative bacterium regarded as an emerging unusual enteric pathogen of increasing public health concern. Our previous work has identified two type VI secretion systems (T6SSs) in , VflT6SS1, and VflT6SS2, and the latter is functional in mediating interbacterial competitiveness. However, its antibacterial effectors remain to be clarified. In this work, we focused on a new potential effector/immunity pair TssI2/TsiI2. Bioinformatics analysis revealed that the C-terminal domain of TssI2 belongs to a widespread family of pesticin, and its antibacterial toxicity and corresponding protection by TsiI2 were proved via bacterial killing assays, and their action sites were localized to the periplasm of bacterial cells. The interaction of TssI2 and TsiI2 was demonstrated by the bacterial adenylate cyclase two-hybrid, protein pull-down and isothermal titration calorimetry assays. Site-directed mutagenesis demonstrated that, in addition to Glu-844, Thr-863, and Asp-869, which correspond to three reported residues in pesticin of , additional residues including Phe-837, Gly-845, Tyr-851, Gly-867, Gln-963, Trp-975, and Arg-1000 were also proved to be crucial to the bactericidal activity of TssI2. Muramidase/lysozyme-related peptidoglycan (PG) hydrolase activities of TssI2 and its variants were validated with permeabilized cells and purified PG substrate. Based on sequence homologies at C-terminals in various isolates, TssI2 was subdivided into five clusters (12-22% identity among them), and the antibacterial activities of representative effectors from other four Clusters were also confirmed through periplasmic over-expression in host. Two selected cognate immunities were proved to confer protection against the toxicities of their effectors. Additionally, TsiI2, which belongs to Cluster I, exhibited cross-protection to effector from Cluster V. Together, current findings expand our knowledge of the diversity and consistency of evolved VgrG effectors in and on how VflT6SS2 mediates a competitive advantage to gain a better survival.
Topics: Type VI Secretion Systems; Periplasm; Muramidase; Escherichia coli; Peptidoglycan; Adenylyl Cyclases; Gastrointestinal Microbiome; Bacterial Proteins; Anti-Bacterial Agents
PubMed: 36288406
DOI: 10.1080/19490976.2022.2136460 -
Marine Pollution Bulletin Nov 2022Mangroves are often exposed to heavy metals that accumulate in the food chain, generate toxicity to mangrove plants and affect microbial diversity. This study determined...
Metagenomic and genomic characterization of heavy metal tolerance and resistance genes in the rhizosphere microbiome of Avicennia germinans in a semi-arid mangrove forest in the tropics.
Mangroves are often exposed to heavy metals that accumulate in the food chain, generate toxicity to mangrove plants and affect microbial diversity. This study determined the abundance of genes associated with resistance and tolerance to heavy metals in the rhizosphere microbiome of Avicennia germinans from a semi-arid mangrove of La Guajira-Colombia by metagenomics and genomics approach. Twenty-eight genes associated with tolerance and 49 genes related to resistance to heavy metals were detected. Genes associated with tolerance and resistance to Cu, especially cusA and copA, were the most abundant. The highest number of genes for tolerance and resistance were for Zn and Co, respectively. The isolate Vibrio fluvialis showed the ability to tolerate Cu, Ni, Zn, and Cd. This work used a complementary approach of metagenomics and genomics to characterize the potential of mangrove microorganisms to tolerate and resist heavy metals and the influence of salinity on their abundance.
Topics: Avicennia; Wetlands; Rhizosphere; Metagenomics; Cadmium; Metals, Heavy; Microbiota
PubMed: 36219973
DOI: 10.1016/j.marpolbul.2022.114204