Schinus weinmanniifolia Mart. ex Engl. (aroeira-rasteira) is a native plant of Brazilian biodiversity. Among Indigenous peoples, the infusion of its leaves is used to relieve sore throats and inflammation. This practice reflects the reliance on traditional medicine in regions with limited access to conventional healthcare. To evaluate the antibacterial activity of the aqueous extract of S. weinmanniifolia leaves (AESW) against Staphylococcus aureus, including methicillin-resistant strains (MRSA), and its effects on bacterial biofilms. The extract was obtained by infusion and characterized by HPLC-DAD. The minimum inhibitory and bactericidal concentration assay, kill time, and enzymatic inhibition were performed, in addition to in vitro and ex vivo antibiofilm activity evaluations. AESW inhibited S. aureus and MRSA at concentrations ranging from 125 to 250μg/mL and exhibited bactericidal effects at 250μg/mL after 8h of treatment. In addition, it reduced DNase and coagulase activities, indicating action on virulence factors associated with cutaneous pathogenesis. In antibiofilm assays, the extract inhibited up to 90% of biofilm formation and reduced the viability of mature biofilms by 70%. In the ex vivo biological model (porcine skin), it inhibited 96% of biofilm formation and reduced 99% of pre-established biofilms after 8h of treatment. These effects were associated with the presence of gallic acid, a phenolic compound reported to possess antimicrobial potential. The extract proved to be a promising alternative for controlling S. aureus, including resistant strains, acting effectively against both planktonic cells and biofilms, reinforcing its therapeutic potential.

Bioelectrochemical detection of viable but non-culturable bacterial cells on screen-printed carbon electrodes.

Biofilm formation and intra-pulsotype variability of Listeria monocytogenes at temperatures relevant to food processing environments.

The formation of resilient biofilms at material interfaces remains a persistent challenge across biomedical, industrial, and environmental systems. Progress has been hindered by the lack of tools that can correlate the spatial chemical heterogeneity of biofilms with the properties of the underlying surface. In this work, we introduce a transformative hyperspectral infrared imaging platform that uniquely integrates three previously disparate capabilities: (i) biomimetic surface engineering to mimic tissue interfaces, (ii) synchrotron infrared microspectroscopy for label-free chemical mapping, and (iii) integration with transcriptomic sequencing to link chemical phenotypes with genetic mechanisms. Using collagen I-functionalized surfaces to mimic biotic interfaces and bare CaF2 as an abiotic control, we demonstrate that surface biochemistry actively guides biofilm architecture and composition. Quantitative analysis revealed clear differences in biofilm thickness and biochemical makeup between biotic and abiotic surfaces. Biofilms formed on collagen exhibited an unrecognized matrix-enriched phenotype, characterized by surface polysaccharide enrichment under copper stress, a response correlated with the upregulation of exopolysaccharide biosynthesis genes. In contrast, planktonic cells underwent acute metabolic disruption. By bridging spatial chemometrics with molecular biology, this study provides a mechanistic framework for understanding and controlling biofilm formation through rational interface design. The approach holds direct implications for antibiofilm surface engineering and infection control strategies.

Cryptococcus laurentii is an emerging opportunistic yeast pathogen associated with unpredictable antifungal susceptibility and biofilm-mediated resistance. This study investigated the therapeutic potential and synergistic interactions of standard antifungals (fluconazole, amphotericin B) and off-target drugs against clinical isolates of C. laurentii. Three clinical isolates recovered from blood (n = 2) and cerebrospinal fluid (n = 1) were confirmed by phenotypic characteristics and PCR amplification of the 18S rRNA gene (~ 480bp). Biofilm formation was screened using Congo red agar and quantified via crystal violet assay. Susceptibility testing employed CLSI-guided disc/well diffusion and broth microdilution methods for antifungals and 14 off-target drugs. Minimum biofilm inhibitory concentrations (MBICs) were determined, and synergistic effects were evaluated using checkerboard assays (fractional inhibitory concentration index, FICI) in planktonic cells and biofilms, supplemented by coverslip biofilm reduction assay. Isolates showed moderate biofilm production (mean OD₅₉₅ = 0.32 ± 0.008), fluconazole susceptibility (mean MIC = 0.77µg/mL), and amphotericin B resistance (mean MIC = 4.48µg/mL). Diclofenac sodium exhibited the strongest off-target activity (mean MIC = 1.32µg/mL). Checkerboard assays revealed synergy between fluconazole + amphotericin B (FICI = 0.5) and fluconazole + diclofenac sodium (FICI = 0.32) in planktonic cells, with additive effects against biofilms (FICI = 0.9). The fluconazole-diclofenac combination significantly disrupted biofilm matrix. Diclofenac sodium enhances fluconazole efficacy and disrupts biofilms, supporting drug repurposing as an adjuvant strategy for managing biofilm-associated C. laurentii infections.

The current situation and perspectives of bacteriophage-derived endolysins for controlling foodborne pathogens and their biofilms in food industry.

Application of endolysin LysPEF1-1 with cinnamon bark against planktonic and mixed-species biofilm cells of Listeria monocytogenes and Enterococcus faecalis on various food and food contact surfaces

Desiccation Tolerance and Persistence of Salmonella enterica and Cronobacter sakazakii on Food Contact Surfaces Based on Cell State and Relative Humidity.

Transcriptomic analysis reveals the multifaceted inhibitory mechanisms of thymol on the survival and virulence of Vibrio alginolyticus.

Phenolic compounds are a versatile class of bioactive molecules with growing applications in different areas, including the food and health sectors. This comprehensive review deals with many aspects related to the study of phenolic compounds, starting with advances in extraction, detection, and quantification methods, going through bioavailability, bioactivity, and beneficial health properties, and discussing antioxidant and antimicrobial uses and mechanisms. The work also discusses strategies related to sustainable use and production with opportunities related to the bioeconomy. Industrial applications include food conservation, active packaging systems, functional foods, nutraceuticals, cosmetics, and pharmaceuticals. Relevant mechanisms of action include destabilization of cellular membranes, enzymatic inhibition, oxidative stress induction, and interference on quorum sensing communication systems, with the potential to be used in anti-virulence approaches. The potential use of phenolic compounds against planktonic and sessile bacterial cells (biofilms) is discussed, as well as their synergistic interactions with antibiotics and bacteriocins, aligned with hurdle technology in the food industry. Phenolic compounds are promising sustainable and innovative alternatives in the food, health, and industrial realms.

Multifaceted antifungal and antibiofilm activities of Mo-CBP2 against Candida species: Structural disruption, cell membrane, cell wall interaction, and synergistic potential.

Staphylococcus aureus biofilms pose significant challenges in medical and industrial settings by exhibiting high resistance to conventional treatments. Although cold atmospheric plasma (CAP) shows promise as an antibacterial agent, the mechanisms of interaction with bacteria, particularly in saline environments, remain poorly understood. S. aureus biofilms were exposed to Argon CAP, and morphological and metabolic changes were evaluated using confocal laser scanning microscopy, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, atomic force microscopy, and XTT fluorescence. Planktonic cells were further examined by transmission electron microscopy. The findings revealed significant biofilm disruption with 94% metabolic inactivation after 300 s. To distinguish direct plasma effects, plasma-treated saline was tested and demonstrated to inactivate within 30 min. Optical emission spectroscopy detected intense Na emission (589 nm) during plasma–saline interactions; however, this observation is reported as a spectral feature rather than a mechanistic conclusion, and further experiments are required to clarify its potential relevance.

Background: ESKAPE constitutes a group of six nosocomial bacteria that can evade available antimicrobials due to their great potential to develop multi-drug resistance and biofilm-forming abilities. These pathogens often cause hospital-acquired infections and pose a serious threat to public health. The search for efficient innovative therapeutic strategies to fight ESKAPE bacteria have been intensively investigated topics. One promising approach to fight resistant pathogens and their biofilms is combination therapy, which allows the effectiveness against microorganisms to be increased while reducing the applied concentrations and risks of potential unwanted side effects. Objectives: The object of the study was to determine if there is an interaction of short lipopeptides ((C10)2-KKKK-NH2, C16-KK-NH2) together with erythromycin and tetracycline against pathogens of the ESKAPE group (Acinetobacter baumannii, Enterobacter aerogenes, Enterococcus faecium Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus). Methods: The checkerboard assay was used to examine the activity of compounds applied in combinations against ESKAPE strains in planktonic cells and toward biofilms formed by Staphylococcus aures and Pseudomonas aeruginosa. Results: The lipopeptides demonstrated a great potential of their application as additives to conventional antimicrobials against Gram-negative bacteria, including microorganisms within biofilms.

Malassezia pachydermatis is a yeast pathogen associated with recurrent skin and ear infections in dogs, often complicated by biofilm formation and reduced antifungal susceptibility. We aimed to evaluate the in vitro antifungal activity of essential oils and nanoemulsions of Zingiber cassumunar and Cymbopogon citratus compared with conventional antifungal agents against planktonic and biofilm forms of M. pachydermatis. Preliminary screening of six plant extracts was performed using 12 clinical isolates identified Z. cassumunar and C. citratus for nanoemulsion formulation. Antifungal susceptibility testing of conventional antifungal agents and nanoemulsions was subsequently conducted using 31 clinical isolates, and nanoemulsions were prepared by high-pressure homogenization. Both essential oils exhibited antifungal activity, and nanoemulsion formulations showed enhanced inhibitory effects compared with the crude oils. Biofilm-associated cells demonstrated reduced susceptibility, particularly to conventional antifungal agents. Terbinafine was the most potent agent against planktonic cells but showed reduced efficacy in biofilms. Nanoemulsions of Z. cassumunar and C. citratus exhibited improved activity against both forms. These findings suggest that nanoemulsification may enhance the in vitro antifungal performance of essential oils against M. pachydermatis biofilms. However, further studies, including mechanistic investigations and in vivo evaluations, are required to confirm their therapeutic potential and safety.

As a single cell grows and multiplies, at what stage does it constitute a swarm? Here, we provide an answer for Bacillus subtilis. We place single planktonic cells onto agar and monitor the biological and physical phases as they transition into an active, swarming cohort. We identify four distinct, nonoverlapping stages enroute to swarming. Using different mutants, we pinpoint the roles of specific cellular processes in the buildup of collective motion. Our results provide a detailed description of the transition from planktonic to a swarming lifestyle-a hallmark of bacterial adaptability to changing environments.

Acinetobacter baumannii is a leading cause of healthcare-associated infections in immunocompromised patients and frequently exhibits multidrug resistance. Cefiderocol, a siderophore cephalosporin, is among the few remaining therapeutic options for infections caused by carbapenem-resistant A. baumannii (CRAB); however, its activity may differ by clonal lineage and can be further compromised in the biofilm state. This study investigates genomic features and cefiderocol efficacy against planktonic and biofilm-associated forms of oncology-derived A. baumannii isolates. Twenty-five non-duplicate, consecutive clinical isolates of A. baumannii from oncology patients underwent whole-genome sequencing and multilocus sequence typing. Cefiderocol activity was quantified in planktonic and biofilm-associated states using minimum bactericidal concentration (MBC) and minimum biofilm eradication concentration (MBEC) assays. Ten sequence types were identified, with the high-risk sequence type 2 (ST2) clone accounting for 56% (14/25) of isolates. ST2 strains showed significantly higher resistance to aminoglycosides, carbapenems, and fluoroquinolones than non-ST2 (NST) strains. The carbapenemase gene bla OXA-23 was detected exclusively in ST2. Colistin and cefiderocol were the most active agents overall. ST2 strains showed higher cefiderocol MBC values than NST strains. However, avibactam significantly reduced cefiderocol MBC in ST2, consistent with class D β-lactamases activity. ST2 and NST isolates exhibited comparable distributions of iron acquisition genes and similar CAS-detected siderophore activity under the assay conditions tested. Cefiderocol activity was significantly reduced in biofilms relative to planktonic cells (median MBEC 2 µg/ml versus median MBC 0.5 µg/ml). NST exhibited higher MBEC/MBC ratios than ST2 isolates, indicating greater biofilm-associated tolerance to cefiderocol. Collectively, these data associate the predominance of oncology-derived ST2 with bla OXA-23 carriage and higher cefiderocol bactericidal thresholds and show that cefiderocol activity is consistently reduced in the biofilm state. Future studies integrating functional measures of iron acquisition and β-lactamase activity will be needed to define the determinants of cefiderocol efficacy across lineages and growth states.

Multidrug-resistant (MDR) pathogens represent a major global health challenge, underscoring the urgent need for new antimicrobial strategies that can effectively target both planktonic cells and biofilm-associated infections. This study integrated in vitro antimicrobial and antibiofilm assays with comprehensive in silico analyses to evaluate the repurposing potential of thymol (TM), sodium azide (SA), and sodium lauryl sulfate (SLS) against 17 bacterial and two fungal strains, including methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates. TM showed the strongest overall antimicrobial activity, with low MIC/MBC values (0.10–0.20 mg/mL) and potent antibiofilm effects (MBIC: 0.20–0.39 mg/mL; MBEC: 0.39–0.78 mg/mL). In contrast, SA exhibited similar MICs (0.10–0.78 mg/mL) but required much higher concentrations for bactericidal and antibiofilm endpoints (MBC/MBIC/MBEC 6.25–100 mg/mL), whereas SLS displayed variable activity, with low MICs against most Gram-positive bacteria (0.10–0.20 mg/mL) but high MBC/MBIC/MBEC values (50–100 mg/mL), especially for Gram-negative biofilms. Molecular docking and 300 ns molecular dynamics (MD) simulations revealed that TM forms stable complexes with key microbial targets, most notably FtsZ (ΔG = –11.0 kcal/mol; Kd = 3.2 × 10 ⁻ ¹⁰ M), supported by favorable MM/GBSA binding energies and restrained motions in principal component analysis/free-energy landscape (PCA/FEL) analyses. SA and SLS were primarily used as mechanistic comparators (respiratory inhibitors and membrane disruptors, respectively). In contrast, their non-ionic analogs, phenyl azide (PA) and lauryl sulfate (LS), were explored as potential scaffolds. LS showed a very high predicted affinity for UDP-3-O-acyl-N-acetylglucosamine deacetylase (LpxC) (ΔG = –19.9 kcal/mol; Kd = 1.7 × 10 ⁻ ¹¹ M), indicating promise for future optimization. In silico ADMET profiling identified TM as the most balanced candidate, combining broad-spectrum antibiofilm efficacy with a comparatively favorable predicted safety profile. Overall, TM emerges as a viable repurposable antimicrobial agent, whereas LS-based derivatives represent computationally prioritized scaffolds that warrant further experimental validation.

The neutrophilic response to chronic Pseudomonas aeruginosa lung infection is strongly associated with collateral tissue damage impairing lung function in people with cystic fibrosis (pwCF). We recently demonstrated the concurrent presence of both biofilm bacteria and planktonic bacteria in chronically infected lungs in pwCF. However, the neutrophilic response to these distinct bacterial forms remains insufficiently characterized. To investigate this, we fractionated P. aeruginosa batch-cultures to enrich for biofilm or planktonic cells. Confocal microscopy showed that aggregates > 30 μm made up > 92.5% of biofilm biomass, while aggregates < 10 μm comprised > 95% of planktonic biomass. Viable cell numbers were validated by similar correlations between CFU/mL and intracellular DNA content. The intensity of the oxidative burst by neutrophils in response to the fractions was estimated by luminol-enhanced chemiluminescence. At low density, biofilm fractions triggered stronger responses than planktonic cells, whereas at high density, planktonic fractions induced the highest activation, indicating density-dependent modulation. These findings suggest that at low densities, biofilms may exacerbate tissue damage by amplifying neutrophil responses. Therefore, the reduced bacterial load in pwCF on ETI therapy could make the balance between biofilm and planktonic P. aeruginosa more critical for lung inflammation, though their distribution under ETI remains unknown.

Methicillin-resistant Staphylococcus aureus (MRSA) remains a major cause of difficult-to-treat infections, largely due to its multidrug resistance and capacity to form persistent biofilms on medical and industrial surfaces. Bacteriophage-derived endolysins have emerged as promising antibacterial agents, but many still require detailed biochemical characterization to support their potential applications. The present study describes the staphylococcal endolysin MV-L expression, purification, and functional analyses, evaluating its ability to control MRSA on surfaces and in biofilms. MV-L was recombinantly produced in Escherichia coli, purified by nickel affinity chromatography; its lytic activity against exponentially growing MRSA was assessed under different physicochemical conditions. Enzyme exhibited optimal activity in slightly alkaline conditions and moderate temperatures; its performance was strongly influenced by ionic strength and divalent cations. Under optimized conditions, MV-L showed markedly increased lytic efficiency and retained activity at low protein concentrations. Beyond planktonic cells, MV-L significantly reduced MRSA loads on glass and stainless steel and disrupted pre-formed biofilms on polystyrene. These findings highlight how buffer composition and ion availability critically modulate MV-L activity and support the concept that tailored endolysins can be integrated as complementary strategies for MRSA control, particularly in scenarios where conventional disinfectants and antibiotics are limited by resistance or poor efficacy against biofilms.

Evaluation of quorum sensing-related mRNA in tap effluent as a biomarker for biofilm dispersal in drinking water distribution systems.