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Plants (Basel, Switzerland) May 2024Drought is one of the main abiotic factors affecting global agricultural productivity. However, the application of bioinocula containing plant-growth-promoting...
Drought is one of the main abiotic factors affecting global agricultural productivity. However, the application of bioinocula containing plant-growth-promoting rhizobacteria (PGPR) has been seen as a potential environmentally friendly technology for increasing plants' resistance to water stress. In this study, rhizobacteria strains were isolated from maize ( L.) and subjected to drought tolerance tests at varying concentrations using polyethylene glycol (PEG)-8000 and screened for plant-growth-promoting activities. From this study, 11 bacterial isolates were characterized and identified molecularly, which include A5-1, A1-2, C7_8, B8-3, A10-11, A9-10, B9-5, B15-6, B12-4, C6-7, and C1-9. All isolates were positive for indole-3-acetic acid (IAA), siderophore, 1-aminocyclopropane-1-carboxylate (ACC) deaminase, ammonia production, nitrogen fixation, and phosphate solubilization, but negative for hydrogen cyanide production. strains A1-2 and C7_8, showing the highest drought tolerance of 0.71 and 0.77, respectively, were selected for bioinoculation, singularly and combined. An increase in the above- and below-ground biomass of the maize plants at 100, 50, and 25% water-holding capacity (WHC) was recorded. Bacterial inoculants, which showed an increase in the aerial biomass of plants subjected to moderate water deficiency by up to 89%, suggested that they can be suitable candidates to enhance drought tolerance and nutrient acquisition and mitigate the impacts of water stress on plants.
PubMed: 38794369
DOI: 10.3390/plants13101298 -
Annals of Clinical Microbiology and... May 2024The population structure and the correlation between antimicrobial resistance (AMR) phenotypes and genotypes in Aeromonas species isolated from patients with...
BACKGROUND
The population structure and the correlation between antimicrobial resistance (AMR) phenotypes and genotypes in Aeromonas species isolated from patients with gastroenteritis are not well understood. The aims of the study were to: (1) investigate the antimicrobial susceptibility profiles of Aeromonas species isolated from patients with gastroenteritis; (2) explore the relationship between AMR genes and resistance phenotypes; and (3) describe the population structure of these isolates and provide evidence of transmission events among them.
METHODS
This microbiological survey was performed at the Microbiology Laboratory of the Emek Medical Center in Afula, Israel. Cultivation of Aeromonas was attempted from stool samples that tested positive by PCR. Antimicrobial susceptibility testing (AST) was performed using the Sensititre GN3F microdilution panel. Whole genome sequencing (WGS) was done using the Illumina NextSeq500/550 system. Phylogenetic studies involved multi-locus sequence typing (MLST) and core genome (cg) MLST. Resistance mechanisms were identified using the Comprehensive Antibiotic Resistance Database and compared with the AST results.
RESULTS
The study included 67 patient-unique isolates. The species that were identified included A. caviae (n = 58), A. dhakensis (n = 3), A. media (n = 2), A. veronii (n = 2) and A. hydrophila (n = 2). Isolates were almost uniformly susceptible to amikacin, gentamicin, aztreonam, cefepime, ceftazidime, ciprofloxacin and meropenem. All isolates with the exception of 1-2 isolates were resistant to ampicillin, cefazolin and ampicillin-sulbactam which was compatible with the presence of the bla genes. Variable resistance rates were observed to cefuroxime, cefoxitin, ceftriaxone, piperacillin-tazobactam that were not correlated with the presence of other β-lactamase genes. Resistance to tetracycline and trimethoprim-sulfamethoxazole correlated with the presence of tetA and sul1, respectively. The population structure of A. caviae was highly diverse with the minority of the isolates (16/57) clustering into six defined sequence types. A cgMLST-based distance of four genes was found in one pair of isolates, suggesting common source transmission.
CONCLUSIONS
A. caviae is the dominant species related to gastroenteritis and is characterized by a diverse population structure, with almost no evidence for common-source transmission. Resistance rates to most antimicrobial agents were low and partially matched with the presence of resistance genes.
Topics: Humans; Gastroenteritis; Aeromonas; Microbial Sensitivity Tests; Anti-Bacterial Agents; Genotype; Phylogeny; Gram-Negative Bacterial Infections; Whole Genome Sequencing; Multilocus Sequence Typing; Child; Phenotype; Adult; Feces; Child, Preschool; Female; Male; Middle Aged; Drug Resistance, Bacterial; Israel; Aged; Infant; Adolescent; Young Adult; Drug Resistance, Multiple, Bacterial
PubMed: 38783344
DOI: 10.1186/s12941-024-00706-2 -
Frontiers in Medicine 2024Infections in humans are mainly caused by , , and . In recent years, has been recognized as widely distributed in the environment, with strong virulence. However, this...
BACKGROUND
Infections in humans are mainly caused by , , and . In recent years, has been recognized as widely distributed in the environment, with strong virulence. However, this bacterial infection usually does not appear in patients with pneumonia as the first symptom.
CASE REPORT
We report a 26-year-old man who was admitted to the hospital with community-acquired pneumonia as the first symptom and developed serious conditions such as hemolytic uremic syndrome, multiple organ dysfunction, and hemorrhagic shock within a short period. He died after 13 h of admission, and the subsequent metagenomic-next generation sequencing test confirmed the finally identified pathogen of infection as .
CONCLUSION
is a rare pathogen identified in the diagnosis of community-acquired pneumonia. Hence, doctors need to develop their experience in identifying the difference between infections caused by pathogenic microorganisms. Medical attention is essential during the occurrence of respiratory symptoms that could be controlled by empirical drugs, such as cephalosporins or quinolones. When patients with community-acquired pneumonia present hemoptysis and multiple organ dysfunction in clinical treatment, an unusual pathogen infection should be considered, and the underlying etiology should be clarified at the earliest for timely treatment.
PubMed: 38695019
DOI: 10.3389/fmed.2024.1289338 -
Microorganisms Mar 2024is widespread in aquatic environments and is responsible for infecting various aquatic animals. In this study, a dominant strain was isolated from the hepatopancreas of...
is widespread in aquatic environments and is responsible for infecting various aquatic animals. In this study, a dominant strain was isolated from the hepatopancreas of diseased and was named JDM1-1. According to its morphological, physiological, and biochemical characteristics and molecular identification, isolate JDM1-1 was identified as . The results of artificial challenge showed isolate JDM1-1 had high pathogenicity to with an LD value of 8.35 × 10 CFU/mL during the challenge test. Histopathological analysis revealed severe damage in the hepatopancreas and gills of the diseased prawns, characterized by the enlargement of the hepatic tubule lumen and gaps between the tubules as well as clubbing and degeneration observed at the distal end of the gill filament. Eight virulence-related genes, namely , , , , , , , and , were screened by PCR assay. In addition, virulence factor detection showed that the JDM1-1 isolate produced lipase, lecithinase, gelatinase, and hemolysin. Furthermore, the mRNA expression profiles of immune-related genes of following infection, including , , , and were assessed, and the results revealed a significant upregulation in the hepatopancreas and intestines at different hours post infection. This study demonstrates that is a causative agent associated with massive die-offs of and contributes valuable insights into the pathogenesis and host defense mechanisms of invasion.
PubMed: 38674638
DOI: 10.3390/microorganisms12040694 -
Frontiers in Veterinary Science 2024is a significant pathogen to various aquatic life. Infections in fish can lead to high mortality rates, causing substantial economic losses in aquaculture. Vaccination...
INTRODCTION
is a significant pathogen to various aquatic life. Infections in fish can lead to high mortality rates, causing substantial economic losses in aquaculture. Vaccination is proposed as a substitute for antibiotics in aquaculture to decrease disease-related mortality and morbidity. Our study previously constructed a -deleted strain of , which provided protective effect to .
METHODS
To further assess the vaccine's applicability, this study evaluated its genetic stability and safety, and the immune protective effects in through four distinct administration routes: intraperitoneal injection, intramuscular injection, oral administration, and immersion, to determine the efficacy of these administration routes.
RESULTS
The results showed that the vaccine remained genetically stable after 45 generations. Immunization via these administration routes was safe for , with intraperitoneal and intramuscular injections causing stronger adverse reactions. Immersion immunization resulted in mild adverse reactions, and no significant adverse reactions were observed following oral immunization. Immunizing at safe concentrations via these routes enhanced the phagocytic activity in serum, increased the levels of non-specific immune-related enzymes (ACP, AKP, C3, C4, LZM, SOD, and IgM), and improved specific serum antibody levels. It also elevated levels of cytokines related to inflammatory responses (IL-1β, IL-10, TNF-α, TGF-β) in organ tissues (liver, spleen, kidney, mid-post intestine, and gills). The survival rates of were measured after challenging with the virulent strain , resulting in the relative survival rates of 64% for Intraperitoneal vaccine group, 56% for Intramuscular vaccine group, 52% for oral vaccine group, and 48% for immersion vaccine group. Analysis of bacterial load in the liver, spleen, and kidney post-challenge showed a decreasing trend in the control group, indicating that the vaccine strain could gradually restrict the rapid proliferation of bacteria in these tissues, thereby providing a certain level of immune protection against .
DISCUSSION
In brief, the vaccine strain can serve as a safe live attenuated vaccine for , and this study lays the foundation for the development of live attenuated vaccines against .
PubMed: 38577546
DOI: 10.3389/fvets.2024.1378448 -
Microbiology Resource Announcements May 2024Extended-spectrum beta-lactamase, AmpC, and carbapenemase-producing bacteria were isolated from raw sewage, effluent, oxidation pond water, and sediment from a...
Extended-spectrum beta-lactamase, AmpC, and carbapenemase-producing bacteria were isolated from raw sewage, effluent, oxidation pond water, and sediment from a wastewater treatment plant in Aotearoa New Zealand. Here, we report the assemblies of 17 isolates belonging to the species , , , , , , , , , and .
PubMed: 38564672
DOI: 10.1128/mra.00131-24 -
PloS One 2024Aeromonas spp. are the opportunistic pathogens that infect both aquatic and terrestrial homeotherms. They were commonly present in aquatic environments, including...
Aeromonas spp. are the opportunistic pathogens that infect both aquatic and terrestrial homeotherms. They were commonly present in aquatic environments, including effluent, tap water, marine, river, and lake, where they are often isolated from aquatic animals, including fish, molluscs, and crustaceans. The Aeromonas infections can cause sepsis, ulcer, and other symptoms, resulting in the death of massive aquatic animals. Therefore, the prevention and control of Aeromonas is of great significance for the healthy development of aquaculture. In this study, we used modern molecular methods to enhance disease control of Aeromonas isolates from freshwater fish in Hebei Province. A total of 130 Aeromonas spp. isolates were isolated from freshwater fish farms in Hengshui, Handan, and Shijiazhuang and all 130 Aeromonas spp. isolates were sequenced for species identification. Of the 130 Aeromonas spp. isolates, 104 isolates were successfully sequenced, and BLAST analysis showed that Aeromonas veronii was predominant in freshwater fish farms in Hebei Province. In addition, 26 antibiotic resistance profiles were obtained from 102 fully cultured isolates among the 104 Aeromonas spp. isolates whose species was primarily identified, and 44 multidrug-resistant bacteria among the 102 isolates were identified using an antibiotic susceptibility test. Using the Multilocus Sequence Typing (MLST) method, 33 out of 44 multidrug-resistant isolates with 14 non-Aeromonas reference strains were selected for phylogenetic and MLST analysis, and all 33 multidrug-resistant isolates were A. veronii. A total of 30 new Sequence Types (STs) were obtained by comparing concatenated sequences (gyrB-groL-gltA-metG-ppsA-recA) on PubMLST website. Furthermore, recombination event analysis detected using RDP5 and ClonalFrameML software 42 and 49 recombination events, respectively, and 22 recombination events were validated by four or more algorithms. Since mutation and recombination events increase clonal diversity and single housekeeping gene sequence alignments are limited for identifying species, we propose the use of multiple concatenated sequence loci to increase discriminatory power. In addition, we propose that the MLST method is an appropriate technique to study and develop the resistance mechanisms of multidrug-resistant Aeromonas and to identify Aeromonas systematically in complex samples obtained from the environment.
Topics: Animals; Aeromonas; Multilocus Sequence Typing; Anti-Bacterial Agents; Phylogeny; Fishes; Drug Resistance, Multiple, Bacterial; Fresh Water
PubMed: 38536889
DOI: 10.1371/journal.pone.0298745 -
The ISME Journal Jan 2024Intestinal microbial disturbance is a direct cause of host disease. The bacterial Type VI secretion system (T6SS) often plays a crucial role in the fitness of pathogenic...
Intestinal microbial disturbance is a direct cause of host disease. The bacterial Type VI secretion system (T6SS) often plays a crucial role in the fitness of pathogenic bacteria by delivering toxic effectors into target cells. However, its impact on the gut microbiota and host pathogenesis is poorly understood. To address this question, we characterized a new T6SS in the pathogenic Aeromonas veronii C4. First, we validated the secretion function of the core machinery of A. veronii C4 T6SS. Second, we found that the pathogenesis and colonization of A. veronii C4 is largely dependent on its T6SS. The effector secretion activity of A. veronii C4 T6SS not only provides an advantage in competition among bacteria in vitro, but also contributes to occupation of an ecological niche in the nutritionally deficient and anaerobic environment of the host intestine. Metagenomic analysis showed that the T6SS directly inhibits or eliminates symbiotic strains from the intestine, resulting in dysregulated gut microbiome homeostasis. In addition, we identified three unknown effectors, Tse1, Tse2, and Tse3, in the T6SS, which contribute to T6SS-mediated bacterial competition and pathogenesis by impairing targeted cell integrity. Our findings highlight that T6SS can remodel the host gut microbiota by intricate interplay between T6SS-mediated bacterial competition and altered host immune responses, which synergistically promote pathogenesis of A. veronii C4. Therefore, this newly characterized T6SS could represent a general interaction mechanism between the host and pathogen, and may offer a potential therapeutic target for controlling bacterial pathogens.
Topics: Type VI Secretion Systems; Gastrointestinal Microbiome; Aeromonas veronii; Symbiosis; Ecosystem; Bacterial Proteins
PubMed: 38531781
DOI: 10.1093/ismejo/wrae053 -
Journal of Medical Case Reports Mar 2024Aeromonas veronii is a very rare and highly pathogenic microorganism. We investigate the clinical characteristics and significance of endogenous endophthalmitis caused...
BACKGROUND
Aeromonas veronii is a very rare and highly pathogenic microorganism. We investigate the clinical characteristics and significance of endogenous endophthalmitis caused by Aeromonas veronii in our patient.
CASE PRESENTATION
A 30-year-old Asian women with systemic lupus erythematosus, uremia, and hypertension developed acute infectious endophthalmitis caused by Aeromonas veronii. After emergency vitrectomy and antibiotic therapy, the clinical condition worsened requiring enucleation.
CONCLUSIONS
Aeromonas veronii can cause infection in the human eye, which can manifest as acute endophthalmitis. Early diagnosis and targeted therapy are important for successful treatment.
Topics: Humans; Female; Adult; Aeromonas veronii; Endophthalmitis; Anti-Bacterial Agents; Vitrectomy; Aeromonas; Gram-Negative Bacterial Infections
PubMed: 38504363
DOI: 10.1186/s13256-024-04412-7 -
Microbial Genomics Mar 2024spp. are associated with a number of infectious syndromes in humans including gastroenteritis and dysentery. Our understanding of the genetic diversity, population...
spp. are associated with a number of infectious syndromes in humans including gastroenteritis and dysentery. Our understanding of the genetic diversity, population structure, virulence determinants and antimicrobial resistance of the genus has been limited by a lack of sequenced genomes linked to metadata. We performed a comprehensive analysis of the whole genome sequences of 447 isolates from children in Karachi, Pakistan, with moderate-to-severe diarrhoea (MSD) and from matched controls without diarrhoea that were collected as part of the Global Enteric Multicenter Study (GEMS). Human-associated isolates exhibited high species diversity and extensive antimicrobial and virulence gene content. , , and were all significantly associated with MSD in at least one cohort group. The and genes that encode components of polar and lateral flagella, respectively, exhibited a weak association with isolates originating from cases of gastroenteritis.
Topics: Child; Humans; Aeromonas; Genomics; Diarrhea; Gastroenteritis; Anti-Infective Agents; Genetic Variation
PubMed: 38451244
DOI: 10.1099/mgen.0.001211