Microbial communities drive the biogeochemical cycles in wetlands and provide a number of ecosystem services. They underpin soil function, and are easily impacted by anthropogenic pressure. This study examined the bacterial microbiome in the natural wetland of Zlato Pole and the protected, periodically flooded rice paddies in the Maritsa River Basin using a metagenomic approach, based on high-throughput sequencing. Alpha-diversity analysis showed a significant variation between the three study sites for Chao1 and ACE (abundance based coverage estimator) richness estimators. A positive correlation was established with pH, with highest values detected for the rice paddies and the lowest, for the Zlato Pole sediments. The obtained sequences were assigned into 37 known bacterial phyla with over 97% bacterial sequences classified within only nine of them. The bacterial communities in rice paddies sediments were more evenly distributed, whereas the Zlato Pole sediment was the most biased. The consortiums in the rice paddies were dominated by Proteobacteria, followed by Actinobacteria and Acidobacteria. The bacterial assemblages in those sites could not be distinguished by analysis of similarity. The Zlato Pole sediment community held an isolated position, where Acidobacteria was replaced by Firmicutes and Bacteroidetes and the microbiome showed an extremely high abundance of Gammaproteobacteria and Bacilli. The dominance of Gammaproteobacteria and the presence of Deinococcus-Thermus phylum, along lower nutrient concentration and the absence of correlation with the environmental parameters, is evidence of constant anthropogenic pressure around the area. The obtained results could be applied in the plans for sustainable management of the protected wetlands.

Lactobacillus is a key genus of probiotics commonly utilized for the treatment of oral infections The primary aim of our research was to investigate the probiotic potential of the newly isolated Levilactobacillus brevis DPL5 strain from human breast milk, focusing on its ability to combat biofilm-forming pathogens such as Staphylococcus aureus. Employing in vitro approaches, we demonstrate L. brevis DPL5′s ability to endure at pH 3 with survival rates above 30%, and withstand the osmotic stress often found during industrial processes like fermentation and freeze drying, retaining over 90% viability. The lyophilized cell-free supernatant of L. brevis DPL5 had a significant antagonistic effect against biofilm-producing nasal strains of Staphylococcus aureus, and it completely eradicated biofilms at subinhibitory concentrations of 20 mg·mL⁻¹. Higher concentrations of 69 mg·mL⁻¹ were found to have a 99% bactericidal effect, based on the conducted probability analysis, indicating the production of bactericidal bioactive extracellular compounds capable of disrupting the biofilm formation of pathogens like S. aureus. Furthermore, genome-wide sequencing and analysis of L. brevis DPL5 with cutting-edge Nanopore technology has uncovered over 50 genes linked to probiotic activity, supporting its ability to adapt and thrive in the harsh gut environment. The genome also contains multiple biosynthetic gene clusters such as lanthipeptide class IV, Type III polyketide synthase (T3PKS), and ribosomally synthesized, and post-translationally modified peptides (RiPP-like compounds), all of which are associated with antibacterial properties. Our study paves the way for the further exploration of DPL5, setting the stage for innovative, nature-inspired solutions to combat stubborn bacterial infections.

The aim of the present study was to investigate biofilm-forming capabilities of clinically isolated strains Escherichia coli, associated with different urinary tract infections. Biofilm production was detected in 36% of the isolates from UTI. Additionally some of virulence factors are estimated to find correlation between antibiotic resistance, hemolysins, morfotypes and biofilm production. Our data indicate that no combination of VFs was highly associated with biofilm production.

Current knowledge on antimicrobial susceptibility pattern of uropathogens is necessary for appropriate therapy. The objective of this study was to investigate antibiotic susceptibility of 28 clinically isolated strains Escherichia coli, associated with different urinary tract infections. Lowest susceptibility detected was for betalactams ampicillin and ampicillin/sulbactam. High susceptibility was detected for aminoglycoside antibiotics. Approximately half of investigated strain showed multidrug resistance profiles. Plasmid content of E. coli isolates was investigated and participation of detected plasmids in drug resistance was discussed. Our data show the high level of antimicrobial resistance and extended spectrum b—lactamases (ESBL) production amongst the uropathogens causing urinary tract infection.

Phospholipases find versatile applications across industries, including detergent production, food modification, pharmaceuticals (especially in drug delivery systems), and cell signaling research. In this study, we present a strain of Bacillus paranthracis for the first time, demonstrating significant potential in the production of phosphatidylcholine-specific phospholipase C (PC-PLC). The investigation thoroughly examines the B. paranthracis PUMB_17 strain, focusing on the activity of PC-PLC and its purification process. Notably, the PUMB_17 strain displays extracellular PC-PLC production with high specific activity during the late exponential growth phase. To unravel the genetic makeup of PUMB_17, we employed nanopore-based whole-genome sequencing and subsequently conducted a detailed genome annotation. The genome comprises a solitary circular chromosome spanning 5,250,970 bp, featuring a guanine–cytosine ratio of 35.49. Additionally, two plasmids of sizes 64,250 bp and 5845 bp were identified. The annotation analysis reveals the presence of 5328 genes, encompassing 5186 protein-coding sequences, and 142 RNA genes, including 39 rRNAs, 103 tRNAs, and 5 ncRNAs. The aim of this study was to make a comprehensive genomic exploration that promises to enhance our understanding of the previously understudied and recently documented capabilities of Bacillus paranthracis and to shed light on a potential use of the strain in the industrial production of PC-PLC.

Staphylococcus aureus biofilms represent a critical healthcare challenge, driving chronic infections and antimicrobial resistance. This study investigates the anti-staphylococcal efficacy of two Lactiplantibacillus strains isolated from traditional Bulgarian pickled vegetables (turshiya): L. plantarum IZITR_24 and L. paraplantarum IZITR_13. Combining whole genome sequencing (WGS) with functional assays, we established a robust genotype-to-phenotype framework to characterize their antimicrobial arsenal. Based on WGS, we identified conserved plantaricin (plnJK, plnEF) clusters in both isolates, with IZITR_13 additionally carrying genes for pediocin and enterolysin A—alongside the confirmed absence of virulence factors. Reconstituted lyophilized cell-free supernatants (LCFSs) were evaluated in dose–response microtiter assays to determine the minimum biofilm inhibitory concentration (MBIC) and minimum inhibitory concentration (MIC). Both strains demonstrated clear, dose-dependent inhibitory activity against the S. aureus growth and biofilm formation. Microscopy (SEM/CLSM) confirmed significant biofilm disruption and cell membrane permeabilization. The observed consistency between genome-inferred capacity and phenotypes highlights the strong predictive value of a genome-first screening approach for selecting bacteriocin-producing lactic acid bacteria (LAB). These findings position IZITR_24 and IZITR_13 as promising postbiotic producers with potent antibiofilm activity against S. aureus. By utilizing their stable postbiotic products rather than relying on live colonization, this study proposes a targeted, antibiotic-sparing strategy to combat persistent staphylococcal biofilms.