Current Microbiology最新文献

Diverse tactics are employed to increase agricultural productivity in order to meet the growing food needs resulting from population growth. Using plant growth-promoting bacteria (PGPB) has proven to be a practical way to apply novel agricultural techniques. Although PGPR derived from rhizospheric soil has been extensively studied, more research on marine microorganisms is required. As marine environment is an extreme environment the marine bacteria is adapted to grow at extreme conditions which enables them to produce various secondary metabolites which can be useful in certain ways. The current study attempts to explore marine microorganisms' capacity to stimulate plant growth. The bacteria isolated form marine environment Microcella sp. strain 23 was found tolerating upto 13% of salinity. This bacterium is able to solubilize various essential minerals such as phosphate and potassium and able to produce ammonia and IAA (Indole-acetic acid), which makes it a possible plant growth promoter. The study was conducted on Pennisetum glaucum (Pearl Millet) crop and pot trials were performed with two groups, control (untreated) and treated with M23 (Microcella sp. coated seeds). Treated plants after 32 days of sowing showed increase in plant shoot length and root length by 48.33% and 29.88% respectively as compared to untreated plants. Microcella sp. M23 acts as plant growth promoter by solubilizing essential minerals, reflected in increased chlorophyll and carotenoid content along with stress markers by activating plants defense system that can protect plant from both biotic and abiotic stresses.

A bisphenol A degrading actinobacterium, strain A6^T, was isolated from a waste digestion system in Chaozhou, China. Cells of strain A6^T were Gram-stain-positive, aerobic, non-spore-forming, non-motile, rod-shaped, and forming yellow colonies on Reasoner's 2 A agar. Phylogenetic analyses based on the 16 S rRNA gene showed that strain A6^T shared 96.8% sequence similarity with Enemella dayhoffiae NML 130,396^T and formed a distinct lineage in the family Propionibacteriaceae in the phylogenetic trees. Genome-based phylogenetic analyses indicated that strain A6^T could be assigned as a novel genus in the family Propionibacteriaceae. The cellular components, including anteiso-C_15:0 (40.0%) as a predominant fatty acid, MK-9(H4) as the major respiratory quinone and a DNA G + C content of 67.2% supported strain A6^T as a member of the family Propionibacteriaceae. However, strain A6^T also contained C_11:0-3-OH (14.4%), iso-C_16:0 (11.3%), and C_11:0 (10.6%) as predominant fatty acids which distinguished it from other genera in the family Propionibacteriaceae. In addition, strain A6^T was negative in enzyme activity of esterase (C4), esterase lipase (C8), aminase of leucine, and negative in the utilization of most carbon sources, which were different from its close related genera in the family Propionibacteriaceae and supported it as a novel genus. Therefore, the name Pseudenemella bisphenolivorans gen. nov., sp. nov. is proposed. The type strain is A6^T (= GDMCC 1.3237^T =KCTC 92291^T).

Listeria monocytogenes (Lm) is a facultative intracellular pathogen responsible for life-threatening listeriosis, characterized by high mortality rates. Currently, there is no vaccine available for the prevention or treatment of listeriosis. Here, we developed two adjuvanted inactivated vaccines and evaluated their safety, immunogenicity, and protective efficacy. The hypervirulent Lm strain XYSN was inactivated with β-propiolactone (BPL) and formulated with AddaVax or Alum to produce inactivated vaccines (ADIV and ALIV) respectively. Local reactogenicity and histopathological observations revealed no adverse reactions in a murine model. Humoral assays demonstrated both ADIV and ALIV induced higher antibody titers against Lm XYSN, with ADIV eliciting stronger cellular immune responses, as indicated by increased IL-17 and IFN-γ expression in spleen cells. Notably, ADIV conferred 83.3% protection against a lethal challenge with hypervirulent Lm strain, representing a 50% increase compared with the 33.3% protection achieved by ALIV. AddaVax adjuvant not only augmented humoral responses to inactivated bacterial cells but also elicited stronger cellular immune responses compared to Alum adjuvants, resulting in enhanced immune protection. This research offers insights into developing novel inactivated vaccines for listeriosis prevention, particularly beneficial for immunocompromised individuals.

To enhance stability and antimicrobial efficacy of antimicrobial peptide (AMP) epinecidin-1, we previously engineered three variants - GK-epi-1, Variant-1 and Variant-2-by substituting alanine and histidine residues with lysine. Our current study focuses on the antifungal capabilities of Epinecidin-1 and its variants against the clinical isolates of Candida spp. (Candida albicans, C. tropicalis, C. krusei & C. glabrata) and Aspergillus flavus. Computational docking studies are evidenced, the peptides had strong affinity against all fungal receptor examined which indicates their efficacy to interact with the Candida cell membrane receptors (Exo-B-(1,3)-Glucanase, Secreted aspartic proteinase (SAP) 1 & N-terminal domain adhesin: Als 9 - 2). Minimum Inhibitory Concentration (MIC), Minimum Fungicidal Concentration (MFC) and antibiofilm assays revealed its potent antifungal activity, particularly in disrupting biofilm formation. Effects of peptides on hyphal growth inhibition activity and Scanning Electron Microscopy (SEM) confirmed that the mechanism of action involves pore formation, hyphal disruption and induction of reactive oxygen species in Candida cell membrane. The antifungal spectrum was extended to A. flavus, a known ocular pathogen, where combination therapy using sub-inhibitory concentrations of Epinecidin-1 and its variant peptides with Amphotericin B and Miconazole showed enhanced synergistic effects, reducing required dosages for effective pathogen control.

Oil contamination poses serious environmental challenges, particularly in hyper-arid desert ecosystems; yet, microbial responses to oil pollution and biostimulation in desert soils remain insufficiently explored. This study explored the microbial community dynamics and hydrocarbon degradation potential to oil contamination and biostimulation in desert soils collected from sites in southern Israel polluted in 1975 and 2014. Laboratory-based biostimulation experiments were conducted over 1.5 years, involving the addition of water (20% or 50% gravimetric saturation), nutrients, and biosurfactants. Results revealed that biostimulation treatments reduced microbial diversity but enriched populations capable of hydrocarbon degradation. Proteobacteria and Actinobacteria were the dominant phyla, comprising 68% to 78% of the total microbial community across both contamination timelines. The relative abundance of Chloroflexi was higher in biostimulated contaminated soils, showing an increase of 41% to 227% compared to untreated contaminated soils. Differential abundance analysis identified distinct taxa of hydrocarbon degraders associated with untreated contaminated soils (e.g., Pseudomonas, Alkanindiges, Bacillus, and Mycobacterium) and biostimulated contaminated soils (e.g., Pseudomonas, Flavobacterium, Pseudoxanthomonas, unclassified Microbacteriaceae, Solimonadaceae, and Gammaproteobacteria). Further, soil hydrophobicity and total petroleum hydrocarbon suggested a positive relationship with the abundance of the nahAc gene, a key marker of hydrocarbon degradation. These findings exhibit that targeted biostimulation with water, nutrients, and biosurfactants accelerates oil biodegradation while selectively reshaping microbial communities toward hydrocarbon degrading taxa in hyper-arid desert soils. This study points to the potential development of effective management and remediation strategies for oil-contaminated desert environments.

The escalating threat of antimicrobial resistance (AMR) necessitates the development of innovative therapeutic approaches. This study reports the green synthesis of magnesium oxide nanoparticles (MgO-NPs) using Citrullus colocynthis extract, a medicinal plant rich in bioactive compounds, as a sustainable alternative to conventional antibiotics. The synthesized MgO-NPs were characterized by UV-Vis spectroscopy (absorption peak at 250 nm), XRD (cubic crystalline structure, 15-25 nm size), SEM-EDX (agglomerated spherical morphology, Mg/O ratio 2.6:1), and FTIR (Mg-O vibration at 860 cm^- 1). The nanoparticles exhibited potent, dose-dependent antibacterial activity against multidrug-resistant (MDR) Staphylococcus aureus [MIC: 35.3 ± 2.1 µg/ml (0.0353 ± 0.0021 mg/ml); MBC: 97.1 ± 3.5 µg/ml (0.0971 ± 0.0035 mg/ml)] and Escherichia coli [MIC: 47.5 ± 4.2 µg/ml (0.0475 ± 0.0042 mg/ml); MBC: 105.5 ± 6.8 µg/ml (0.1055 ± 0.0068 mg/ml)], with a bactericidal mode of action (MBC/MIC ≤ 4). Remarkably, MgO-NPs restored susceptibility to β-lactam antibiotics (ceftazidime and penicillin) in resistant strains, demonstrating synergistic effects. Antifungal activity of MgO-NPs against Candida albicans (17.3 ± 0.7 mm) and Aspergillus niger (14.4 ± 0.8 mm) at a concentration of 10 mg/ml was also observed. Phytochemical analysis revealed solvent-dependent bioactive constituents in C. colocynthis, with aqueous extracts rich in tannins/phenolics and methanolic extracts rich in flavonoids/terpenoids. This is the first report demonstrating the restoration of antibiotic susceptibility by MgO-NPs synthesized from C. colocynthis extract.

Myroides odoratimimus is an emerging opportunistic pathogen increasingly implicated in infections across human and animal populations. We previously reported the first outbreak of pneumonia in post-weaning piglets associated with M. odoratimimus, marking a significant shift in its recognized host range. The affected swine herd exhibited co-infection with Porcine Circovirus types 2 and 3 (PCV2 and PCV3), likely contributing to proliferative dermatitis and nephropathy syndrome (PDNS), reproductive abnormalities and immunosuppression. This study presents the genomic characterization of a multidrug-resistant strain (M. odoratimimus pgdne) isolated during the outbreak. Whole-genome sequencing revealed multiple antimicrobial resistance determinants-including the chromosomally encoded blaMUS-1 metallo-β-lactamase-and several virulence-associated factors. Genotype-phenotype correlation demonstrated strong concordance. Phylogenetic analysis (distance method, 1,000 bootstrap replicates) showed close relatedness with human isolates, suggesting zoonotic potential. These findings underscore the pathogenic capacity of M. odoratimimus in immunocompromised animal hosts and highlight its relevance to public health and thereby reinforces the need for integrated One Health-based surveillance and control strategies targeting emerging multidrug-resistant pathogens.