Folia Microbiologica[JOURNAL]
Sun
200 papers
Selenium nanoparticles functionalized with bacitracin: a novel approach for combating multidrug-resistant bacteria and evaluating lymphocyte response.
Ahmed ME, Salman MF, Alsharif SA … +6 more , Alwutayd KM, Alkhateeb MA, Wizrah MSI, Allemailem KS, Alateeq R, Said A
Folia Microbiol (Praha) · 2026 May · PMID 42154433 · Publisher ↗
Green synthesis of nanoparticles has emerged as a promising approach to develop cost-effective, biocompatible, and environmentally friendly antimicrobial agents. In this study, we investigated the biosynthesis of seleniu...
Green synthesis of nanoparticles has emerged as a promising approach to develop cost-effective, biocompatible, and environmentally friendly antimicrobial agents. In this study, we investigated the biosynthesis of selenium nanoparticles (SeNPs) using bacitracin-like inhibitory substances (BLIS) derived from Acinetobacter baumannii. We evaluated their antimicrobial, antibiofilm, and anticancer potential against multidrug-resistant (MDR) pathogens. The synthesized SeNPs were characterized using spectroscopic and imaging techniques, confirming their nanoscale size, hexagonal morphology, surface roughness, and a characteristic absorption peak at 270 nm. Antimicrobial activity was assessed against clinically isolated MDR bacteria and fungi, in which SeNPs demonstrated significant growth inhibition, with a minimum inhibitory concentration (MIC) of 250 mg/mL. Biofilm formation among Acinetobacter baumannii isolates showed variable biofilm-producing capacities, and treatment with SeNPs effectively reduced biofilm formation. Furthermore, gene expression analysis revealed significant downregulation of the mexB efflux pump gene in Pseudomonas aeruginosa following SeNP treatment, indicating a potential mechanism for overcoming antimicrobial resistance. Cytotoxicity evaluation using human lymphocytes demonstrated that SeNPs exhibited minimal toxicity, supporting their biocompatibility. In addition, the nanoconjugate system showed notable anticancer activity against the tested cancer cell lines. In conclusion, BLIS-mediated SeNPs represent a promising multifunctional nanoplatform with potent antimicrobial activities, alongside low cytotoxicity toward normal human cells. These findings highlight their potential application in combating MDR infections and advancing nanomedicine-based therapeutic strategies.
Exploring the anticancer potential of Streptomyces sp. M4 extract: effects on apoptosis in gastric cancer ags cells.
Parsamehr A, Salehghamari E, Jalali H
Folia Microbiol (Praha) · 2026 May · PMID 42149331 · Publisher ↗
Gastric cancer is a leading cause of cancer-related mortality worldwide, emphasizing the need for novel therapeutic strategies. Actinobacteria are prolific producers of bioactive secondary metabolites with anticancer pot...
Gastric cancer is a leading cause of cancer-related mortality worldwide, emphasizing the need for novel therapeutic strategies. Actinobacteria are prolific producers of bioactive secondary metabolites with anticancer potential. In this study, we evaluated the antitumor activity of Streptomyces sp. M4 extract against the human gastric adenocarcinoma (AGS) cell line and explored its underlying mechanisms. The strain was cultured in starch casein broth, and metabolites were extracted using ethyl acetate. AGS cell were treated with the crude extract, and cytotoxicity was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, while apoptosis was analyzed by flow cytometry. Gene expression was measured using real-time PCR, and Caspase-3/7 activity was determined via colorimetric assays. The MTT assay revealed potent cytotoxicity with an IC value of 26.15 µg/mL at 24 h. Annexin V-propidium iodide (PI) staining revealed that Streptomyces sp. M4 extract significantly induced apoptosis in AGS cells, as evidenced by a 79.35% increase in the apoptosis rate compared to that of the control group. Real-time PCR analysis demonstrated a 1.785-fold upregulation of CASPASE-8, whereas CASPASE-9 expression decreased to 0.068-fold relative to control. Additionally, BCL-2 was upregulated (4.752-fold), whereas BAX was downregulated (0.08-fold) in extract-treated cells. Caspase activity assays revealed a significant increase in Caspase-3/7 activity (0.761 mU/mL), indicating apoptosis induction. These findings suggest that Streptomyces sp. M4 extract exerts anticancer effects primarily through the extrinsic apoptotic pathway while modulating key survival and resistance mechanisms of cancer cells. This study underscores the potential of Streptomyces sp. M4 as a therapeutic agent in gastric cancer.
Investigation of symbiotic-like interactions between Pseudomonas chlororaphis and non-pathogenic Fusarium sp. for enhanced biopreparation potential.
Mis B, Kuşcu MC, Eltem R
Folia Microbiol (Praha) · 2026 May · PMID 42126686 · Publisher ↗
The rhizosphere layer of the soil is a complex environment where various organisms interact with each other. Understanding this complex structure and utilising its interactions in industry can provide significant benefit...
The rhizosphere layer of the soil is a complex environment where various organisms interact with each other. Understanding this complex structure and utilising its interactions in industry can provide significant benefits in many areas, particularly in sustainable agriculture. In this study, the symbiotic effects between plant growth-promoting (PGP) Pseudomonas chlororaphis and non-pathogenic Fusarium sp. were examined, and symbiotic-like culture experiments were conducted for potential biopreparation production. Initially, the PGP properties of the interacting species were qualitatively screened, and their non-pathogenicity was confirmed in vitro. Then, symbiotic-like culture trials were performed with the selected species. Subsequently, the quantitative PGP properties of these species, both individually and in symbiotic-like culture, were determined. The symbiotic-like culture significantly enhanced phosphate solubilization and IAA production efficiency by approximately 70%. Moreover, the antifungal effects of all symbiotic-like cultures increased and remained effective for 15 days. This study demonstrates the potential of harnessing microbial interactions in the rhizosphere to develop biopreparations with enhanced plant growth-promoting and antifungal properties. Based on the results, important steps have been taken by clarifying the naturally occurring symbiosis in the rhizosphere of soil and paving the way to develop biopreparations with higher efficiency by leveraging interactions between microorganisms.
The role of microbial biosurfactants in enhancing wound repair: a comprehensive review.
Das S, Rao KVB
Folia Microbiol (Praha) · 2026 May · PMID 42118518 · Publisher ↗
Wound healing is still considered a complex clinical challenge, particularly when complicated by microbial infections, impaired tissue regeneration, and persistent inflammation. Conventional wound care strategies, includ...
Wound healing is still considered a complex clinical challenge, particularly when complicated by microbial infections, impaired tissue regeneration, and persistent inflammation. Conventional wound care strategies, including synthetic surfactant-based dressings and hydrogels, are often limited by cytotoxicity, poor biodegradability, and decreased compatibility with host tissues. To address these limitations, biosurfactants-naturally occurring surface-active compounds produced by microorganisms-have drawn considerable attention for their therapeutic potential in wound management. These molecules exhibit lower toxicity, enhanced biodegradability, and unique physicochemical characteristics compared to their synthetic surfactants, making them attractive candidates for biomedical applications. The intervention of biosurfactant-based wound care has been explored through topical formulations, hydrogel composites, and innovative dressing materials intended to accelerate wound closure. Their antibacterial and antifungal properties help to reduce microbial load, while anti-inflammatory activity aids modulation of the wound microenvironment, facilitating tissue regeneration and re-epithelialization. When compared with traditional wound care therapies, biosurfactant-based systems show superior safety, environmental sustainability, and therapeutic efficacy. For instance, biosurfactant-incorporated hydrogels provide improved drug delivery capacity, moisture balance, and biofilm-disrupting ability, outperforming the performance of traditional formulations. Recent investigations indicate that biosurfactants enhance wound healing by accelerating wound closure, reducing the risk of infection, and promoting the regeneration of damaged tissues. Nevertheless, challenges such as production scalability, stability in complex formulations, and the need for rigorous clinical validation remain obstacles to their widespread adoption. Overall, biosurfactants represent a promising frontier in wound management, offering a sustainable, biocompatible, and multifunctional alternative to conventional therapies with the potential to advance next-generation wound care strategies significantly.
Trophic status as a factor in phytoplankton resilience to the toxic effects of zinc oxide nanoparticles.
Solomonova E, Shoman N, Akimov A
Folia Microbiol (Praha) · 2026 May · PMID 42108369 · Publisher ↗
A study was conducted on the effect of zinc oxide nanoparticles (ZnO NPs) on the structural and functional characteristics of the micro-nanophytoplankton community in the Black Sea under different nutrient conditions. It...
A study was conducted on the effect of zinc oxide nanoparticles (ZnO NPs) on the structural and functional characteristics of the micro-nanophytoplankton community in the Black Sea under different nutrient conditions. It was found that the intensity and nature of the impact of ZnO NPs on the phytoplankton community are determined by the trophic status of the environment. In the nutrient-enriched sample, 20 µg L of ZnO NPs inhibited algal growth; however, the community demonstrated compensatory capabilities, manifested as a restructuring of the taxonomic structure with an increase in the proportion of tolerant species. A concentration of 40 µg L of ZnO NPs induced a pronounced suppression of physiological processes, critically limiting phytoplankton productivity. Under nutrient deficiency, both tested concentrations of ZnO NPs (20 and 40 µg L) caused irreversible suppression of cell division and photosynthetic activity, while exposure to the 40 µg L dose led to the elimination of the algal community. It is shown that the trophic status of the aquatic environment is a critical factor determining the resilience of the phytoplankton community to the toxic effects of zinc oxide nanoparticles. Nutrient deficiency makes the community extremely vulnerable to the toxic effects of ZnO NPs, while high nutrient availability provides the metabolic resources for detoxification and the restoration of phytoplankton photosynthetic activity.
In Vitro probiotic assessment and optimization of enhanced spore production in submerged fermentation of Bacillus toyonensis OQ071612.
El-Sayed SE
Folia Microbiol (Praha) · 2026 May · PMID 42096107 · Publisher ↗
Certain species within the Bacillus genus, such as Bacillus toyonensis, are widely used as commercial probiotics; however, comprehensive screening and safety evaluation remain essential because some Bacillus species, inc...
Certain species within the Bacillus genus, such as Bacillus toyonensis, are widely used as commercial probiotics; however, comprehensive screening and safety evaluation remain essential because some Bacillus species, including B. anthracis and B. cereus, are pathogenic and toxin-producing. In the present study, a soil-derived isolate, B. toyonensis OQ071612, exhibited strong inhibitory activity against multiple representative human enteropathogens and was therefore selected for detailed characterization. The strain demonstrated high tolerance to harsh gastrointestinal and processing-related stress conditions, including low pH, simulated gastric fluid, simulated intestinal fluid, bile salts, and elevated temperatures. In addition, B. toyonensis OQ071612 displayed several desirable probiotic attributes, such as antioxidant activity and bile salt hydrolase (BSH) activity, while showing no hemolytic activity and minimal cytotoxicity toward Caco-2 cells. Antibiotic susceptibility testing revealed sensitivity to vancomycin, levofloxacin, sulfamethoxazole, and doxycycline, with intermediate sensitivity to azithromycin and amoxicillin, indicating the absence of acquired antimicrobial resistance associated with mobile genetic elements. Response surface methodology (RSM) was employed to optimize biomass and spore production, achieving optimal conditions at pH 6.5, 40 °C, 150 rpm agitation, and 0.26 vvm aeration, resulting in 2.7-fold and 6.5-fold increases in biomass and spore yields, respectively. Furthermore, supplementation with B. toyonensis OQ071612 significantly enhanced body mass gain in rats, supporting its potential as a probiotic candidate for animal feed and suggesting possible relevance for future human applications. Collectively, these findings demonstrate that B. toyonensis OQ071612 possesses strong probiotic functionality, favorable preclinical safety characteristics, and promising industrial scalability, supporting its potential as a probiotic candidate for animal feed applications and providing a basis for future evaluation in human-related applications.
Phytochemical characterization, antioxidant, and antibacterial activities of Cymbopogon citratus extracts against multidrug-resistant uropathogens.
Khalid K, Naz S, Javaid A … +1 more , Rashid A
Folia Microbiol (Praha) · 2026 May · PMID 42091839 · Publisher ↗
Urinary tract infections (UTIs) are among the most prevalent bacterial infections worldwide, posing a significant health burden, particularly in the context of rising antimicrobial resistance. The increasing ineffectiven...
Urinary tract infections (UTIs) are among the most prevalent bacterial infections worldwide, posing a significant health burden, particularly in the context of rising antimicrobial resistance. The increasing ineffectiveness of conventional antibiotics has necessitated the exploration of alternative therapeutic approaches, especially those derived from natural plant-based sources. This study aimed to evaluate the antimicrobial efficacy of Cymbopogon citratus (lemongrass) leaf extracts against multidrug-resistant uropathogens. Extracts were prepared using three solvents: methanol, ethanol, and n-hexane, and tested against three clinically relevant bacterial strains: Escherichia coli, Bacillus subtilis, and Enterobacter hormaechei subsp. xiangfangensis. Phytochemical screening revealed that extracts contained a wide variety of bioactive compounds, including alkaloids, flavonoids, saponins, tannins, terpenoids, phenols, coumarins, and volatile oils. Further analysis using Fourier-transform infrared spectroscopy identified characteristic functional groups, including O-H, C-H, C = O, C = C, and N-H, indicating the presence of alcohols, aldehydes, ketones, alkenes, and amines, which are often associated with antimicrobial activity. Antibacterial assays showed that the methanolic extract exhibited the strongest inhibitory activity. In disc diffusion tests, it produced the largest zones of inhibition: 14 mm against Escherichia coli, 14 mm against Bacillus subtilis, and 13 mm against Enterobacter hormaechei subsp. xiangfangensis. Minimum inhibitory concentration values further confirmed its superior potency, with results of 3.12 mg/mL for Escherichia coli, 6.25 mg/mL for Bacillus subtilis, and 12.5 mg/mL for Enterobacter hormaechei subsp. xiangfangensis. The extract also showed bactericidal activity, with minimum bactericidal concentrations of 12.5 mg/mL for Escherichia coli and 25 mg/mL for the other two strains. In summary, this study provides strong evidence that Cymbopogon citratus, particularly when extracted with methanol, possesses significant antibacterial and antioxidant properties against multidrug-resistant uropathogens. These findings support its potential use as a complementary or alternative therapeutic agent in managing resistant urinary tract infections, offering a promising natural strategy to address the growing challenge of antimicrobial resistance. IMPACT STATEMENT. Methanolic extracts of Cymbopogon citratus demonstrated strong antibacterial and bactericidal activity against multidrug-resistant uropathogens, including Escherichia coli and Enterobacter hormaechei subsp. xiangfangensis. Phytochemical and FTIR analyses confirmed the presence of bioactive functional groups associated with antimicrobial effects. These findings highlight lemongrass as a promising plant-based candidate for developing complementary therapies to address antimicrobial resistance in urinary tract infections and support further pharmacological standardization and clinical investigation.
Laser-ablated gold nanoparticles: a novel approach to antimicrobial artificial eyes.
Mohamed A, El-Gendy AO, Abdelkader KSE … +3 more , Ahmed E, Mohamed T, Mobarak M
Folia Microbiol (Praha) · 2026 May · PMID 42091838 · Publisher ↗
Patients with artificial eyes often suffer from severe, persistent microbial infections, particularly due to antibiotic-resistant strains such as methicillin-resistant Staphylococcus aureus (MRSA). Nowadays, gold nanopar...
Patients with artificial eyes often suffer from severe, persistent microbial infections, particularly due to antibiotic-resistant strains such as methicillin-resistant Staphylococcus aureus (MRSA). Nowadays, gold nanoparticles (AuNPs) exhibit strong antimicrobial properties, offering a promising solution to this challenge. In this study, laser ablation was employed to create AuNPs, which were added into artificial eye materials during fabrication. The antimicrobial efficacy of laser-ablated AuNPs against resistant bacteria was systematically evaluated using multiple microbiological assays. A colony forming unit and growth kinetic analysis were determined using an ANOVA test. Moreover, Logistic and Gompertz models were performed to visualize the MRSA growth kinetic rate. Our findings show that AuNPs significantly reduce bacterial growth, suggesting their potential as an effective antimicrobial component in ocular prostheses. Theoretically, the Gompertz model was the best-fit model for experimental kinetic data. We have produced a foundational framework for integrating AuNPs into artificial eyes to combat infections, paving the way for the development of novel antimicrobial ocular prostheses.
Co-existence of blaCTX-M and mcr-1 in avian pathogenic Escherichia coli in Southern Xinjiang: current status and antimicrobial resistance characteristics.
Yang B, Xing G, Ma W … +4 more , Qi M, Jing B, Li J, Wu J
Folia Microbiol (Praha) · 2026 May · PMID 42090104 · Publisher ↗
Extended-spectrum β-lactamases (ESBLs) constitute one of the principal mechanisms underlying multidrug resistance (MDR) in avian pathogenic Escherichia coli (APEC). The coexistence of ESBL-encoding genes, particularly bl...
Extended-spectrum β-lactamases (ESBLs) constitute one of the principal mechanisms underlying multidrug resistance (MDR) in avian pathogenic Escherichia coli (APEC). The coexistence of ESBL-encoding genes, particularly blaCTX-M, together with the plasmid-mediated colistin resistance gene mcr-1 in APEC raises serious concern, as it undermines the effectiveness of third-generation cephalosporins and colistin. To clarify the current epidemiological status and potential transmission risks associated with the co-occurrence of ESBL and mcr-1 genes in southern Xinjiang, 133 liver samples from chickens that had died after exhibiting clinical signs consistent with colibacillosis were collected, from which 100 of these isolates (75.2%, 100/133) were confirmed as APEC. The double-disk diffusion test revealed that 65 strains (65.0%, 65/100) were ESBL-producing. Among these ESBL-producing APEC isolates, resistance rates to ampicillin, cefazolin, ceftiofur, and cefoxitin were 100% (65/65), 100% (65/65), 92.3% (60/65), and 4.6% (3/65, intermediate/susceptible), respectively. PCR detection revealed that 95.4% (62/65) carried blaCTX-M and 93.8% (61/65) carried blaTEM and five isolates (7.7%, 5/65) were resistant to colistin and carried the mcr-1 gene. Integron analysis revealed that int1 was detected in 98.5% (64/65) of the ESBL-APEC isolates. Notably, all five mcr-1-positive strains co-harbored int1. These five isolates exhibited MDR phenotypes and were assigned to phylogenetic groups A (n = 1), B1 (n = 3), and D (n = 1). Whole-genome sequencing (WGS) revealed that the five mcr-1-positive APEC strains belonged to four sequence types (STs): ST6792 (n = 1), ST1196 (n = 2), ST155 (n = 1), and ST162 (n = 1), and harbored three blaCTX-M subtypes (blaCTX-M-55 [n = 3], blaCTX-M-64 [n = 1], and blaCTX-M-65[n = 1]). Furthermore, these strains carried IncI2 or IncFIB plasmid replicons alongside the int1 integrase gene, highlighting the co-occurrence of critical resistance determinants with mobile genetic elements known to facilitate horizontal dissemination. The coexistence of blaCTX-M and mcr-1 in high-risk clones such as ST155 and ST162, which are associated with human infections worldwide, indicates that the region faces a threat from multidrug-resistant strains and a potential risk of cross-species transmission. Given the limited geographic scope and sample size, our findings should be considered a preliminary warning. Future studies with expanded sampling and experimental validation of horizontal transfer are needed to fully assess the transmission risks.
Pharmacological and mechanistic assessment of Trachyspermum ammi hydrosol: antimicrobial and anti-biofilm efficacy against Staphylococcus aureus and Listeria monocytogenes.
Srivastava D, Gupta K, Kumar P … +6 more , Kaushal S, Srivastava S, Pant Y, Chanotiya CS, Rout PK, Pal A
Folia Microbiol (Praha) · 2026 May · PMID 42081074 · Publisher ↗
The escalating global threat of antimicrobial resistance (AMR), particularly among biofilm-forming bacterial pathogens, has necessitated the development of novel therapeutic strategies. Trachyspermum ammi hydrosol has ex...
The escalating global threat of antimicrobial resistance (AMR), particularly among biofilm-forming bacterial pathogens, has necessitated the development of novel therapeutic strategies. Trachyspermum ammi hydrosol has exhibited a range of bioactive properties. However, its potential as a dual-action antimicrobial agent targeting both planktonic and biofilm-associated microorganisms remains underexplored. This study aimed to explore the antibacterial and antibiofilm activity of T. ammi hydrosol (TaHy) against two major Gram-positive pathogens, Staphylococcus aureus (S. aureus) and Listeria monocytogenes (L. monocytogenes), and elucidate its mechanism of action based on cell. Additionally, we aimed to evaluate in vivo acute toxicity and biosafety. Antimicrobial activities were assessed using DDA, MIC, and time-kill assays. Antibiofilm activity was evaluated using a crystal violet method, and biofilm morphology was examined by microscopy. TaHy demonstrated efficient inhibition in hydrophobicity and EPS production, along with alterations in membrane integrity, including bacteriolysis and protein and nucleic acid release. Our results showed that the MIC of TaHy was 0.625 mg/mL against both pathogens and that it significantly inhibited and eradicated biofilm formation at sub-MIC values, as confirmed by SEM and fluorescence microscopy. TaHy effectively inhibited hydrophobicity and EPS production, reducing the virulence factors of pathogens to 1/8 MIC. Consequently, in vivo acute oral toxicity tests revealed no adverse effects at doses up to 2000 mg/kg body weight of hydrosol concentrate. These findings revealed that TaHy has robust antimicrobial and antibiofilm capability against S. aureus and L. monocytogenes.
Probiotic potential and antioxidant, antidiabetic, and anticancer activities of goat milk-derived lactic acid bacteria.
Tinrat S, Jiraprasertwong O
Folia Microbiol (Praha) · 2026 May · PMID 42081073 · Publisher ↗
Raw goat milk was explored as a source of lactic acid bacteria (LAB) with potential probiotic properties. Following 16S rRNA gene sequencing, Lactiplantibacillus plantarum PP101-STR and Lactococcus lactis PP104-STR were...
Raw goat milk was explored as a source of lactic acid bacteria (LAB) with potential probiotic properties. Following 16S rRNA gene sequencing, Lactiplantibacillus plantarum PP101-STR and Lactococcus lactis PP104-STR were selected for further probiotic assessment. L. plantarum PP101-STR exhibited broad antagonistic activity against both Gram-positive and Gram-negative pathogens, especially Salmonella enterica ATCC 13312 and maintained high viability (> 83%) under simulated gastric conditions (pH 2.0-3.0) and bile salt exposure. This strain also demonstrated high cell surface hydrophobicity, along with strong auto-aggregation and co-aggregation capacities, which were associated with significantly enhanced adhesion to Caco-2 and HT-29 cell lines and effective competitive exclusion of pathogenic bacteria (p≤0.05). In addition, L. plantarum PP101-STR displayed strong antioxidant activity, as determined by total phenolic content, FRAP, DPPH, and ABTS assays, exceeding that of L. lactis PP104-STR. Its cell-free supernatant (CFS) exhibited notable α-glucosidase and α-amylase inhibitory activities, indicating potential for glucose regulation. Antiproliferative evaluation revealed that L. plantarum PP101-STR markedly suppressed colorectal cancer cell growth in a dose-dependent manner. Importantly, low lactate dehydrogenase release (8.11-8.86%) and maintained viability in MRC-5 cells indicated minimal membrane damage and low cytotoxicity toward normal cells, supporting a non-lytic mechanism potentially involving apoptosis-related pathways. On the basis of the present finding, L. plantarum PP101-STR demonstrates strong probiotic potential and multiple biologically relevant activities in vitro, supporting its further investigation in applications related to intestinal health.
Pomegranate peel extract as a promising tyrosyl-tRNA synthetase inhibitor of Staphylococcus aureus: in vitro and in silico approach.
Chaudhary A, Murmu S, Behera SK … +3 more , Kamra A, Chaurasia A, Kumar S
Folia Microbiol (Praha) · 2026 May · PMID 42065831 · Publisher ↗
Staphylococcus aureus, a common foodborne pathogen, thrives in various environments, including milk, meat, and vegetables. With increasing consumer concerns about the harmful effects of chemical additives, alternative an...
Staphylococcus aureus, a common foodborne pathogen, thrives in various environments, including milk, meat, and vegetables. With increasing consumer concerns about the harmful effects of chemical additives, alternative antimicrobial agents are urgently needed. This study evaluates the potential of pomegranate peel extract (PPE) as an inhibitor of the bacterial enzyme tyrosyl-tRNA synthetase (TyrRS). PPE, rich in bioactive compounds such as ellagitannins, ellagic acid, and gallic acid, was extracted using hot water, microwave, and ultrasound methods. The ultrasound assisted extract showed the highest phenol content (178.6 ± 0.6 GAE/g) and antioxidant activity (9.43 ± 1.6 µmole TE/g DW). The MIC value of this extract was found to be 2.0 mg/ml and it inhibited S. aureus growth significantly (20.6 ± 0.31 mm) in agar diffusion tests. To elucidate the molecular mechanism, in silico analyses including molecular docking, molecular dynamics simulations, and MM-PBSA calculations were performed for major PPE-derived phytochemicals, gallic acid, ellagic acid, punicalagin, and punicalin, along with the reference TyrRS inhibitor SB-219,383. Among the tested compounds, punicalagin exhibited the most favorable binding affinity and dynamic stability, with binding free energy comparable to SB-219,383. These findings highlight PPE's potential in combating S. aureus along with utilization of agricultural by-products as source of antimicrobial substance that has the potential of offering a sustainable approach to antimicrobial resistance.
Investigation of chitinase B1 inhibitors targeting the cell wall biosynthetic machinery in Aspergillus fumigatus through integrated molecular dynamics and QM/MM.
Alam P, Akhtar A, Hasan Z … +3 more , Serajuddin M, Almarfadi OM, Ahmed S
Folia Microbiol (Praha) · 2026 Apr · PMID 42060100 · Publisher ↗
Aspergillus fumigatus (A. fumigatus), an opportunistic fungal pathogen, poses a significant threat to immunocompromised individuals due to increasing resistance to existing antifungal therapies. Targeting fungus-specific...
Aspergillus fumigatus (A. fumigatus), an opportunistic fungal pathogen, poses a significant threat to immunocompromised individuals due to increasing resistance to existing antifungal therapies. Targeting fungus-specific enzymes, such as A. fumigatus chitinase B1 (AfChiB1), which plays a critical role in cell wall remodeling, represents a promising alternative therapeutic strategy. In this study, an integrated computational workflow was employed to screen a food-derived natural compound library for potential AfChiB1 inhibitors. Three candidate inhibitors—Plantacyanin, Amentoflavone, and Conferone—along with caffeine as a reference compound, were identified through library screening followed by re-docking of DFT-optimized structures. Molecular dynamics (MD) simulations exceeding 500 ns demonstrated that Conferone exhibited the highest binding stability, supported by consistently low RMSD and RMSF values. Although Amentoflavone showed favorable QM/MM energy values, it displayed pronounced ligand drift, while Plantacyanin exhibited moderate stability. Principal component analysis and free energy landscape profiling corroborated the MD results, revealing that Conferone occupied deep energy minima with limited conformational flexibility. QM/MM calculations further confirmed the electronically favorable nature of Amentoflavone and the robust dynamic behavior of Conferone. Superimposition of initial and refined MD structures indicated stable binding conformations for all ligands. Overall, Conferone emerged as the most promising computationally predicted AfChiB1 inhibitor, although experimental validation will be required to confirm its antifungal activity. These findings highlight the antifungal potential of food-derived bioactive compounds and the value of integrated computational approaches, although experimental validation is required to substantiate these predictions.
Identification of a novel mutation of sat (Gly82Arg) in Shigella flexneri serotype 7a: insights into clinical relevance.
Nisa I, Qasim M, Driessen A … +8 more , Nijland J, Rahman H, Yousafzai YM, Alzahrani KJ, Mattner J, Muhammad N, Bari F, Khan TA
Folia Microbiol (Praha) · 2026 Apr · PMID 42060099 · Publisher ↗
Virulence factors can vary between Shigella (S.) flexneri serotypes. The current study characterized virulence genes among 199 S. flexneri from different serotypes in Peshawar, Khyber Pakhtunkhwa Province, Pakistan, by s...
Virulence factors can vary between Shigella (S.) flexneri serotypes. The current study characterized virulence genes among 199 S. flexneri from different serotypes in Peshawar, Khyber Pakhtunkhwa Province, Pakistan, by sequence analysis. Moreover, using the homology model, the 3D protein structure of the serine autotransporter toxin (sat) from S. flexneri was examined for the first time to determine structural changes in the mutant sat protein. Interestingly, the present study reported that ial(spa29/spaR) gene has not shown any relationship to the previously known sequence of S. flexneri, but it has a striking resemblance to previously reported cases that were identified in Shigella dysenteriae and Escherichia coli. Furthermore, 15 strains of S. flexneri, all of which are members of serotype 7a, were found to carry the single-point mutation (G246A) in sat, which resulted in an exchange of amino acid (Gly82Arg). Preliminary data reveal a potential link between the sat gene mutation and severe clinical illness patients; however additional study is needed to verify this relation. Overall, the results of the mutant sat proteins homology model validation showed a slight, but not significant, alteration in protein structure.
Quinolinequinone-based sulfonamide bioisosteres as promising antimicrobial agents.
Yıldırım H, Yıldız M, Bayrak N … +6 more , Özer B, Sridhar D, Mataracı-Kara E, AnandaThangadurai S, Jayaprakash V, TuYuN AF
Folia Microbiol (Praha) · 2026 Apr · PMID 42047986 · Publisher ↗
In the search for novel antimicrobial agents, a series of aminated quinolinequinone derivatives (AQQ1-13) were synthesized and evaluated for their in vitro antibacterial and antifungal activities. These compounds were co...
In the search for novel antimicrobial agents, a series of aminated quinolinequinone derivatives (AQQ1-13) were synthesized and evaluated for their in vitro antibacterial and antifungal activities. These compounds were constructed via sulfonamide linkers incorporating commercially available p-aminobenzenesulfonamides bearing diverse heteroaromatic or acyl substituents. The antibacterial activity was assessed against four gram-negative and three gram-positive bacterial strains, while antifungal activity was evaluated against three fungal species using the CLSI-approved broth microdilution method. Several compounds demonstrated moderate antimicrobial activity when compared with standard reference drugs. Notably, three AQQs (AQQ7, AQQ9, and AQQ11) exhibited notable antibacterial activity against Enterococcus faecalis, with a minimum inhibitory concentration (MIC) value of 78.12 µg/mL, showing lower MIC values than amikacin under the tested conditions (MIC = 128 µg/mL) under the same conditions. Time-kill studies revealed bactericidal effects at 1× and 4× MIC levels, while combination studies demonstrated synergistic interactions with levofloxacin, particularly for AQQ11. Furthermore, AQQ9 and AQQ11 exhibited antibiofilm activity in combination therapy, including inhibition of biofilm formation and partial disruption of preformed biofilms. In silico ADMET and molecular docking analyses identified AQQ9 as a compound of interest, showing favorable drug-likeness properties and favourable binding interactions toward E. faecalis DNA gyrase. Overall, these findings highlight quinolinequinone-based sulfonamide bioisosteres as potential scaffolds for further development of combination therapies targeting gram-positive and biofilm-associated infections.
D-amino acids inhibit biofilm formation in Escherichia coli and increase antibiotic susceptibility in multidrug-resistant bacteria.
Wang J, Yang B, Xing G … +5 more , Zhao Y, Wu Z, Li J, Qi M, Wu J
Folia Microbiol (Praha) · 2026 Apr · PMID 42047985 · Publisher ↗
Escherichia coli infections in lambs lead to substantial morbidity and significant economic losses within the global sheep industry and causes substantial economic losses. This study investigated antibiotic resistance in...
Escherichia coli infections in lambs lead to substantial morbidity and significant economic losses within the global sheep industry and causes substantial economic losses. This study investigated antibiotic resistance in E. coli isolated from diarrheic sheep in the Ta’e Reclamation Area of Xinjiang, Northwest China, and examined the effects of D-amino acids on biofilm formation. A total of 73 isolates were subjected to phylogenetic grouping, antibiotic susceptibility testing, resistance gene detection, biofilm assays, and evaluation of D-amino acid effects. The isolates were classified into groups A (20.6%), B1 (46.6%), and D (32.8%). High resistance rates were observed for ampicillin (67.1%), tetracycline (56.2%), streptomycin (53.4%), and gentamicin (52.1%); 47.9% exhibited multidrug resistance. Sixteen resistance genes were identified, with aph3’ (82.2%), blaTEM (75.3%), and cmlA (68.5%) being most prevalent. Biofilm formation occurred in 72.6% of isolates. D-methionine, D-leucine, D-tryptophan, and D-tyrosine significantly inhibited biofilm formation, an effect specific to D-enantiomers as confirmed by L-amino acid controls. Growth curve analysis revealed that D-tyrosine and D-tryptophan inhibited biofilm at concentrations that did not affect planktonic growth, whereas D-methionine and D-leucine exhibited growth-inhibitory effects at biofilm-suppressing concentrations. qPCR further demonstrated that D-tyrosine and D-tryptophan downregulated luxS, csgD, and pgaC. Overall, sheep-derived E. coli in Northwest China exhibit significant antibiotic resistance. D-amino acids inhibit biofilm formation and show synergistic effects with antibiotics, suggesting their therapeutic potential.However, the underlying regulatory mechanisms require further investigation.
Gum Arabic-assisted green synthesis, characterization, antimicrobial, antibiofilm and antiparasitic activities of silver-selenium nanoparticles: Reaction mechanism determination.
Almayouf MA, Al-Habeeb RS
Folia Microbiol (Praha) · 2026 Apr · PMID 42035395 · Publisher ↗
The study looked at a safe way to synthesize and validate silver-selenium nanoparticles using Gum Arabic as a good green reducing and stabilizing agent which is then characterized by techniques like scanning electron mic...
The study looked at a safe way to synthesize and validate silver-selenium nanoparticles using Gum Arabic as a good green reducing and stabilizing agent which is then characterized by techniques like scanning electron microscopy with mapping, energy dispersive X-ray spectroscopy elemental analysis, zeta potential, dynamic light scattering analysis, and transmission electron microscopy. We evaluated the efficacy of the synthesized silver-selenium nanoparticles as a smart antimicrobial agent by evaluating their ability to inhibit the tested Gram-positive, Gram-negative bacteria, and unicellular fungi, the minimal amount needed to stop their development, and their efficacy in preventing biofilm formation. We used the membrane leakage test to ascertain the kinetic analysis and potential mechanism of the antimicrobial response. The worm and larval stages of Trichinella spiralis were subjected to bioassay and LC50 and LC90 determination. The produced silver-selenium nanoparticles are all almost the same size, round or oval, range from 37 to 18.3 nm with an average diameter of 10.9 ± 1.9 nm and a range of 3.7 to 18.3 nm. Silver-selenium nanoparticles exhibit an encouraged efficacy against Staphylococcus aureus and Staphylococcus epidermidis (41.0 mm in antimicrobial tests), with minimum inhibitory concentration (MIC) values of 1.56 and 0.781 µg/mL, respectively. Next in line are the unicellular fungi; Candida albicans 32.0 mm (MIC = 1.562 µg/mL), B. subtilis 31.0 mm (MIC = 3.125 µg/mL), and Candida tropicalis 40.0 mm (MIC = 3.125 µg/mL). The greatest notable decrease in biofilm generation was observed in Candida albicans treated with 1.562 ppm (MIC) of silver-selenium nanoparticles (90.82%), followed by Staphylococcus aureus (77.92%) treated with 0.7812 ppm (MIC) of silver-selenium nanoparticles and Klebsiella pneumoniae (77.80%) treated with 1.562 ppm (MIC) of silver-selenium nanoparticles. The low amount (10 µg/mL) of silver-selenium nanoparticles had the smallest impact on Trichinella spiralis, causing less than 48% death even after 48 h, while higher amounts (50–200 µg/mL) led to complete death at 48 h (50 µg/mL), and 200 µg/mL worked quickly, causing complete death by 36 h. The promising findings suggested that the produced silver-selenium nanoparticles could be applied against harmful bacteria, parasites, and yeasts as we enter a new era for battling disease resistance in biomedical domains.
Design, synthesis, and antimicrobial evaluation of heteroaromatic or acyl-substituted benzenesulfonamide-linked aminoquinolinequinones.
Yıldırım H, Yıldız M, Bayrak N … +7 more , Özer B, Mataracı-Kara E, Hacıoğlu M, Biswas A, Özbek-Çelik B, Jayaprakash V, TuYuN AF
Folia Microbiol (Praha) · 2026 Apr · PMID 42033593 · Publisher ↗
A series of aminated quinolonequinones (AQQ1-13) was synthesized from quinolinequinone and substituted aromatic amines containing a sulfonamide group with conformationally restricted heterocyclic structures or an acyl gr...
A series of aminated quinolonequinones (AQQ1-13) was synthesized from quinolinequinone and substituted aromatic amines containing a sulfonamide group with conformationally restricted heterocyclic structures or an acyl group. The obtained AQQs were characterized by various spectroscopic techniques including FTIR, NMR, and MS analyses. Structural modifications of the sulfonamide group in these compounds were selected by introducing various heterocyclic substituents, such as isoxazole, thiadiazole, pyridine, pyrimidine, pyrazine, and pyridazine, or by attaching acyl groups (acetyl or benzamide) with different substituents. Some of the synthesized AQQs exhibited antifungal activity against the tested strains, with potencies comparable to the reference drugs under the tested conditions. Noticeably, AQQ5 with thiadiazole moiety attached to the sulfonamide group showed inhibitory activity against C. albicans (MIC: 19.53 µg/mL). The most active compound AQQ5 also showed the best antifungal potency towards to other two fungi (C. parapsilosis and C. tropicalis). However, it should be noted that antifungal activity was evaluated only against ATCC strains. Considering the increasing prevalence of antifungal resistance, these results may not fully reflect the efficacy against clinical isolates. Antifungal resistance may render the antifungal activity already seen against ATCC strains ineffective in clinical isolates. Yet the putative target, farnesyl pyrophosphate synthase identified through in silico protocols suggests that farnesyl pyrophosphate synthase may be a potential target, warranting further experimental validation.
Streptomyces thermolilacinus-mediated synthesis of Selenium Nanoparticles as biocompatible anti-inflammatory agent; characterization, radiolabeling, in vitro and in vivo evaluations.
El-Enain IMA, Handak EM, Hassane MK … +3 more , Elqasem AAA, El Hassanien S, Elkhouly HI
Folia Microbiol (Praha) · 2026 Apr · PMID 42029851 · Publisher ↗
The biosynthesis of selenium nanoparticles (SeNPs) using Actinomycetes Streptomyces thermolilacinus IMA7 offers an environmentally friendly method for production without traditional manufacturing processes. These SeNPs d...
The biosynthesis of selenium nanoparticles (SeNPs) using Actinomycetes Streptomyces thermolilacinus IMA7 offers an environmentally friendly method for production without traditional manufacturing processes. These SeNPs demonstrate reduced toxicity and enhanced biocompatibility, making them ideal for biomedical applications. The synthesis was characterized through multiple analytical techniques, including UV, XRD, TEM, EDX, zeta potential, DLS, and FTIR. DLS results indicated varied particle sizes between 50.75 nm and 396.1 nm, with a predominant size around 91.28 nm, and TEM imaging confirmed an average particle size of 70.53 nm with a uniform spherical shape. FTIR and EDX analyses validated nanoparticle synthesis, while UV spectroscopy identified a peak at 282 nm. The SeNPs exhibited high stability, indicated by a zeta potential of -35.5 mV. In vitro antibacterial assessment against Gram-positive and Gram-negative bacteria revealed inhibition zones of 2.2667 ± 0.251 cm to 2.8 ± 0.1126 cm. Additionally, SeNPs showed potent COX-2 inhibition with an IC50 value of 2.227 ± 0.08 µg/ml, achieving an 85.5% inhibition at 100 µg/ml. Biodistribution studies in vivo, facilitated by radio labeling with radioactive 131I and intravenous injection in both normal and pre-inflamed mice, assessed the anti-inflammatory properties of SeNPs. Further in vivo studies were performed to validate some immunological, histopathological and immunohistochemical parameters. Serum levels of tumor necrosis factor-α, prostaglandin E2 and interleukin-10 were measured. Liver tissues were examined for histopathological and nuclear factor kappa B p65 immunoreactivity. Finally, SeNP treatment significantly attenuated inflammatory responses and ameliorated hepatic inflammatory alterations, supporting its potential as an anti-inflammatory nanotherapeutic agent.
Advances in tools, strategies, and applications of mining of microbial genomes for novel antimicrobials: a comprehensive review.
Krishan B, Kumar A, Azmi W
Folia Microbiol (Praha) · 2026 Apr · PMID 42018076 · Publisher ↗
Amidst the escalating crisis of antimicrobial resistance globally, genome mining has emerged as a promising field for the discovery of newer antibiotics from microbial sources. Secondary metabolites like non-ribosomal pe...
Amidst the escalating crisis of antimicrobial resistance globally, genome mining has emerged as a promising field for the discovery of newer antibiotics from microbial sources. Secondary metabolites like non-ribosomal peptides, polyketides, and ribosomally synthesized post-translationally modified peptides are synthesized by biosynthetic gene clusters and exhibit diverse pharmacological activities. Advanced sequencing technologies and informatics studies have made high-precision identification and prediction of cluster function possible. Computational tools like antiSMASH, BAGEL, PRISM, and RiPPMiner are the core of BGC classification and characterization of derived metabolites from microbial genomes. Heterologous expression, microbial co-culture, elicitor induction, and genetic regulation have been used in various strategies to induce cryptic or silent gene clusters, leading to improved production of novel compounds. The combination of bioinformatics and synthetic biology has yielded higher precision in prediction and understanding of biosynthesis. Therefore, genome mining is an economical and productive approach for the discovery of next-generation antimicrobials, offering a potential solution to the global healthcare catastrophe caused by multidrug-resistant pathogens.
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