Antibiofilm Activity Research Articles

Mechanistic Insights into the Antibiofilm Activity of Simvastatin and Lovastatin against Bacillus subtilis.

Statins have been reported for diverse pleiotropic activities, including antimicrobial and antibiofilm. However, due to the limited understanding of their mode of action, none of the statins have gained approval for antimicrobial or antibiofilm applications. In a recent drug repurposing study, we observed that two statins (i.e., Simvastatin and Lovastatin) interact stably with TasA(28-261), the principal extracellular matrix protein of Bacillus subtilis, and also induce inhibition of biofilm formation. Nevertheless, the underlying mechanism remained elusive. In the present study, we examined the impact of these statins on the physiological activity of TasA(28-261), specifically its interaction with TapA(33-253) and aggregation into the amyloid-like structure using purified recombinant TasA(28-261) and TapA(33-253) in amyloid detection-specific in vitro assays (i.e., CR binding and ThT staining assays). Results revealed that both statins interfered with amyloid formation by the TasA(28-261)-TapA(33-253) complex, while neither statin inhibited amyloid formation by lysozyme, a model amyloid-forming protein. Moreover, neither statin significantly altered the expressions of terminal regulatory genes (viz, sinR, sinI) and terminal effector genes (viz, tasA, tapA, and bslA) involved in biofilm formation by B. subtilis. While the intricate interplay between Simvastatin and Lovastatin with the diverse molecular constituents of B. subtilis biofilm remains to be elucidated conclusively, the findings obtained during the present study suggest that the underlying mechanism for Simvastatin- and Lovastatin-mediated inhibition of B. subtilis biofilm formation is manifested by interfering with the aggregation and amyloid formation by TasA(28-261)-TapA(33-253). These results represent one of the first experimental evidence for the underlying mechanism of antibiofilm activity of statins and offer valuable directions for future research to harness statins as antibiofilm therapeutics.

Samarium oxide coated by rutin: synthesis, antibiofilm, antivirulence and bactericidal activity evaluation

Samarium oxide coated by rutin: synthesis, antibiofilm, antivirulence and bactericidal activity evaluation

Nano CaCO3 mediated in vitro and in vivo wound healing characteristics of chitosan films without added drugs.

Nano CaCO3 mediated in vitro and in vivo wound healing characteristics of chitosan films without added drugs.

Synergistic Artemisia monosperma with royal jelly: antibacterial, antioxidant, antibiofilm, and anti-Alzheimer assay

This investigation aimed to examine the synergistic effects of fresh royal jelly and local wild Artemisia monosperma leaf extract as antibacterial, antioxidant, antibiofilm, and anti-Alzheimer activity. Gas chromatography-mass spectrometry (GC–MS) identified 16 compounds in Artemisia monosperma, including tricosadiynoic acid, hexadecenoic acid, octadecenoic acid. In contrast, fresh royal jelly contained 13 compounds, including dodecanoic acid, octadecynoic acid, hexadecenoic acid, heptatriacotanol, and their derivatives. The Artemisia monosperma extract exhibited significant antioxidant activity in the DPPH assay, with IC50 value of 5.48 ± 0.002 µg/mL. Fresh royal jelly exhibited an IC50 value of 14.56 ± 0.004 µg/mL. Both substances exhibited significant antibacterial activity in comparison to gentamycin. The Synergistic combination (1:1) effectively suppressed the growth of multidrug-resistant bacterial species, including Bacillus subtilis (ATCC 6633), Enterococcus faecalis (ATCC 10541), Staphylococcus aureus (ATCC 6538), Klebsiella pneumoniae (ATCC 13883), Salmonella typhi (ATCC 6539), and Pseudomonas aeruginosa (ATCC 90274), and decreased biofilm activity. Additionally, in vitro the of inhibition activity (IC50) of the Butyrylcholinesterase enzyme (BChE) for the plant extract, royal jelly and the Synergistic combination were 4.35 ± 0.002 µg/mL, 4.9 ± 0.002 µg/mL, and 3.55 ± 0.002 µg/mL, respectively while the IC50 of rivastigmine (positive control) was 3.9 ± 0.002 µg/mL. in silico analysis reported that the bioactive compounds demonstrated high binding affinities, between − 6.6 and − 10.3 kcal/mol, against the human acetylcholinesterase protein, beside ADMET analysis exhibited high gastrointestinal absorption and potential inhibitory effects on CYP1A2 and CYP2C9 enzymes. Our study indicated that the synergistic effect of Artemisia monosperma and royal jelly bioactive compounds exhibited a promising antibacterial, antioxidant, antibiofilm, and acetylcholinesterase inhibitory activities.

A novel antimicrobial peptide Larimicin78-102 from large yellow croaker (Larimichthys crocea) shows potent antibacterial activity in vitro and enhances resistance to vibrio fluvialis infection in vivo.

A novel antimicrobial peptide Larimicin78-102 from large yellow croaker (Larimichthys crocea) shows potent antibacterial activity in vitro and enhances resistance to vibrio fluvialis infection in vivo.

Lavandula dentata leaves as potential natural antibiofilm agents against Pseudomonas aeruginosa

Biofilm formation is responsible for persistent diseases related to chronic infections. Mostly it is triggered by many bacteria, mainly Pseudomonas aeruginosa (P. aeruginosa). In this study, plants that have been used traditionally in skin infections Viz; Liquorice, Carrot, Red Cabbage, Beetroot, Turmeric, Neem, and French Lavender were selected to evaluate their antibiofilm activity against P. aeruginosa. The microtiter plate assay was used to evaluate their antibiofilm activity against P. aeruginosa as well as ability to reduce the activity of P. aeruginosa. To investigate the phytocompounds responsible for bioactivity of the superior extract and to explore potential interactions between its bioactive components and one of quorum-sensing (QS) regulatory proteins of P. aeruginosa involved in biofilm formation, liquid chromatography-mass spectrometric (LC-MS) and molecular docking studies were done. The study showed that all tested plant extracts could significantly (p-value < 0.05) reduce the formation of P. aeruginosa biofilm. The methanol extract of Lavandula dentata (L. dentata) leaves is superior at 0.625 mg/mL. In conclusion, the study revealed the presence of phenolic acids, flavonoids, and their glycosides also, the anti-P. aeruginosa biofilm activity of L. dentata leaves was reported herein for the first time and could be a good source of leads for antibiofilm medicine.

Self-Assembly, Antimicrobial Properties and Biodegradability of Ester-Functionalized Choline-Based Surface-Active Ionic Liquids

Choline-based ionic liquids (ILs) have gained attention as antimicrobial and antibiofilm agents due to their biocompatibility and tuneable antimicrobial properties. However, a significant drawback of amphiphilic choline-based ILs is their decreasing biodegradability as the alkyl chain length increases. To address this issue and enhance the ecotoxicological profile of these compounds, a labile ester functionality was incorporated into the alkyl side chain. This strategic modification aims to improve biodegradation rates while maintaining the desirable antimicrobial properties of the ILs. A series of ester-functionalized choline-based ionic liquids (CnECholBr) with alkyl chains containing from 10 to 14 carbon atoms were synthesized, and their self-aggregation behaviour in aqueous solutions was studied. Their antimicrobial properties were then tested against clinically significant bacteria and yeasts, as well as their effectiveness in eliminating MRSA and C. albicans biofilms. Furthermore, the ecotoxicological properties of these compounds were investigated by assessing their aerobic biodegradability and aquatic toxicity using luminescent bacteria. The results indicated that CnECholBr exhibit higher surface activity and biodegradation rates than non-functionalized choline-based ILs. Conversely, their antimicrobial and antibiofilm activity was found to be lower to that of non-functionalized choline-based ILs. Among the compounds evaluated, the C12ECholBr was identified as the most effective antimicrobial and antibiofilm agent.

Combatting Acinetobacter baumannii Pneumonia by Multidrug Codelivery of Curcumin Nanosuspensions and Sulfamethoxazole with Polymyxin B for Targeted Pediatric Pulmonary Inflammation and Disease Management.

Combatting Acinetobacter baumannii Pneumonia by Multidrug Codelivery of Curcumin Nanosuspensions and Sulfamethoxazole with Polymyxin B for Targeted Pediatric Pulmonary Inflammation and Disease Management.

Lactobacillus acidophilus (strain Scav) Postbiotic Metabolites Reduce Infection and Modulate Inflammation in an in vivo model of Pseudomonas aeruginosa wound infection.

This study assessed the antibacterial, anti-biofilm, and immunomodulatory activity of Lactobacillus acidophilus (strain Scav) postbiotic (LaP) in a mouse model of Pseudomonas aeruginosa wound infection and evaluated the bioactive components of the LaP. LaP was tested for P. aeruginosa clearance and immunomodulatory activity during wound infection. We show that LaP applied 1 hour after infection reduced tissue bacterial burden within 24 hours, and this reduction persisted for 5 days. Ciprofloxacin given once at the exact same time did not reduce bacteria load as compared to vehicle controls. LaP reduced plasma IL-6 and MCP-1 levels after 5 days. Wound tissue IL-6 and MCP-1 levels were increased in infected vehicle mice at 5 days, but tissues from LaP treated mice were similar to sham controls. LaP increased tissue IL-10 (anti-inflammatory cytokine) levels. Ciprofloxacin decreased plasma and tissue IL-6 compared to vehicle controls but did not affect MCP-1 or IL-10 levels. To elucidate antibacterial and anti-biofilm metabolite(s) in LaP, fractionation followed by P. aeruginosa antagonistic activity assays were performed. This was followed by liquid chromatography coupled to mass spectrometry (LCMS) analysis. Our analyses identified a low molecular weight, polar molecule which had both antibacterial and anti-biofilm activity. L. acidophilus secretes an antibacterial and anti-biofilm metabolite that reduced pathogen burden, resolved systemic inflammation in a P. aeruginosa wound infection model.

First metabolic profiling of Indian wild edible mushroom Amanita hemibapha reveals antimicrobial compounds that infers selective activity against gram-positive human pathogens

Amanita hemibapha, a wild edible mushroom from Western Ghats area of India, has been underexplored for its therapeutic properties. The present study uncovered selective inhibition of gram-positive human pathogens by the mushroom extracts and antibiofilm activity as the first report among the Amanita genus. The chloroform extract displayed the most effective inhibition against Streptococcus pyogenes, with both Minimum inhibitory concentration and Minimum bactericidal concentration registering at 6 mg/mL, and effective biofilm inhibition was recording at 4 mg/mL. Metabolic profiling of the chloroform fraction revealed an array of fatty acids, especially oleic acid and its derivatives like Oleoyl lysophosphatidylcholine and Azelaic acid, known to be selective for gram-positive pathogens. Sphingolipids like D-Sphingosine, Safingol, and threo-sphingosine profiled in the extract are effective gram-positive inhibitors. Metabolic profiling revealed the presence of medicinal and health-beneficial fatty acids/lipids in A. hemibapha.

Antibacterial and Antibiofilm Activities of Hydralazine, an Antihypertensive Drug: In Vitro and In Silico Approaches

Background: The rise of multidrug-resistant (MDR) bacteria poses a significant challenge to global public health, contributing to increased morbidity and mortality rates. In this context, the repurposing of existing drugs has emerged as a promising strategy. In this study, hydralazine (HDZ), a vasodilator used as an antihypertensive since 1952, demonstrated antibacterial and antibiofilm activity against both Gram-positive and Gram-negative bacteria. Methods: In this study, the antibacterial activity of the antihypertensive hydralazine (HDZ) was evaluated against Gram-positive and Gram-negative strains through minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), growth curve with MIC and sub-MIC doses, combinatorial effect with gentamicin, scanning electron microscopy (SEM), molecular docking, and antibiofilm activity. Results: The MIC and MBC values ranged from 39.5 to 1.250 μg/mL, respectively. A change in the growth kinetics of the strains was observed when exposed to MIC and 1/2 MIC values, with a delay in the phases of up to 12 h. The combinatorial effect with gentamicin demonstrated an additive and indifferent potential when combined with HDZ. Conclusions: Furthermore, hydralazine showed antibiofilm activity against the tested strains, including MRSA. Electron microscopy analysis revealed significant changes in bacterial morphology when exposed to the MIC dose of HDZ for 4 h. The overall results of the study indicate hydralazine as a potential agent in the fight against bacterial infections.

Stigmurin encapsulated PLA–PEG ameliorates its therapeutic potential, antimicrobial and antiproliferative activities

In light of growing global challenge posed by antimicrobial resistance, it is very important to explore alternatives that can target pathogenic microorganisms. One such strategy involves the use of antimicrobial peptides (AMPs) and Stigmurin is one such AMP present in Brazilian scorpion Tityus stigmurus which possesses antimicrobial, antiproliferative and antiparasitic activity. The study commenced with successful synthesis and characterization of Stigmurin and its analogues, designated S1 and S2. Studies on Stigmurin and its analogues have demonstrated that analogues exhibit enhanced antimicrobial efficacy but often lead to increased hemolysis, limiting their therapeutic application. To prevent the associated toxicity of these peptides, PLA–PEG di-block copolymer was synthesised to prepare nanoparticles (E-WT, E1, and E2) with an average diameter of approximately 160–180 nm. The core of the research involved evaluating the antimicrobial (Bacillus subtilis), antibiofilm (B. subtilis and Pseudomonas aeruginosa), antiproliferative (HEK293 and RAW264.7) and hemolytic activity of the peptides. In addition to the experimental work, in silico analysis using structural models was conducted to further understand their potential interactions. The findings demonstrated that the analogue peptides exhibit enhanced antimicrobial and antibiofilm activity compared to the wild-type Stigmurin. Moreover, encapsulating the peptides in PLA–PEG nanoparticles maintained the antimicrobial activity against B. subtilis. Further, encapsulation significantly reduced hemolysis as well as cytotoxicity by 10–20%, thereby improving their safety profile.Graphical abstract

Phosphorylated chitosan and nano-sized TMP: Enhancing strength, antibiofilm action, and biocompatibility of restorative glass ionomer cements.

Phosphorylated chitosan and nano-sized TMP: Enhancing strength, antibiofilm action, and biocompatibility of restorative glass ionomer cements.

Antibacterial and anti-biofilm activities of Derazantinib (ARQ-087) against Staphylococcus aureus.

The global rise of multidrug-resistant pathogens, particularly methicillin-resistant Staphylococcus aureus (MRSA), represents a critical public health challenge. This study evaluates the antibacterial and anti-biofilm activities of Derazantinib (ARQ-087) against S. aureus. ARQ-087 exhibited minimum inhibitory concentration (MIC) values ranging from 4 to 16 µM against S. aureus reference laboratory strains and diverse clinical MRSA isolates, demonstrating strong antibacterial activity with minimal resistance development. Time-kill assays demonstrated a concentration- and time-dependent reduction in bacterial viability. Crystal violet staining assays revealed that ARQ-087 significantly inhibited MRSA biofilm formation in a dose-dependent manner. Additionally, ARQ-087 exhibited strong anti-biofilm activity against pre-formed biofilms, as shown by colony counts and confocal laser scanning microscopy, which indicated extensive biofilm disruption and bacterial cell death. Mechanistic studies revealed that ARQ-087 disrupts bacterial membrane integrity, as evidenced by SYTOX Green and DISC3(5) fluorescence assays, while inducing intracellular ATP depletion and reactive oxygen species generation, contributing to bacterial death. ARQ-087 also displayed negligible hemolytic activity and no acute toxicity observed in a Galleria mellonella infection model. In this model, ARQ-087 prolonged the survival of larvae infected with S. aureus. These findings highlight ARQ-087 as a promising therapeutic candidate for treating MRSA infections and biofilm-associated diseases. Further preclinical studies are needed to confirm its potential for clinical application.

Essential oils and Lactobacillus metabolites as alternative antibiofilm agents against foodborne bacteria and molecular analysis of biofilm regulatory genes

The formation of biofilm by foodborne pathogens increases the risk of foodborne diseases, resulting in major health risks. Research on strategies for eliminating biofilm formation by foodborne pathogens is urgently needed. Therefore, the objective of this study was to construct a new technique for controlling foodborne bacteria and inhibiting the biosynthesis of biofilm via using natural products. The essential orange oil (EOO) and cell-free filtrate of Lactobacillus pentosus RS2 were used as antibacterial and antibiofilm agents against B. cereus RS1, the strongest biofilm-forming strain. The mixture of cell-free filtrate (CFF) and EOO (CFF/EOO) was the best antibiofilm agent under all tested conditions. The minimal inhibitory concentration (MIC) test revealed that 400 μl ml−1 CFF and 16 μl ml−1 EOO completely inhibited the growth of B. cereus. The treatment of three commercial surfaces with CFF/EOO resulted in a high reduction in biofilm synthesis, with adhesion percentages of 33.3, 36.3, and 40.8% on stainless steel, aluminum foil, and aluminum, respectively. The aluminum surface had the greatest adhesion with B. cereus RS1 among the three tested surfaces. These results were confirmed by expression analysis of three essential coding genes, sinR, calY, and spo0A, participating in biofilm formation in B. cereus. The biofilm-negative regulator gene sinR was overexpressed, whereas the biofilm-positive regulator genes calY and spo0A were down-expressed in B. cereus RS1 after treatment with antibiofilm agents, compared with those in the untreated sample. This study revealed that CFF/EOO was more effective at activating sinR (2.099 ± 0.167-fold increase) and suppressing calY and spo0A (0.314 ± 0.058 and0.238 ± 0.04-fold decrease, respectively) compared to control. This result confirmed the biochemical estimation of biofilm formation in B. cereus after treatment with all the experimental agents. The EOO and CFF of L. pentosus RS2 can be used as strong antibacterial and antibiofilm agents against foodborne bacteria. These products reduced the biofilm formation on trade surfaces affecting the expression of three essential biofilm regulatory genes. This study considered novel research concerning the potential antibiofilm activity of EOO combined with CFF of L. pentosus and the molecular analysis of genes regulating biofilm production under stress of CFF/EOO.

Antimicrobial activity of ear cleanser products against biofilm and planktonic phases of Staphylococcus spp. and Pseudomonas spp. isolated from canine skin and ear infections

BackgroundStaphylococcus spp., and Pseudomonas spp., including multidrug resistant staphylococci are frequent isolates from canine otitis externa and atopic dermatitis. The ability of these bacteria to form biofilms significantly contributes to the chronic nature of otitis. To manage microbial overgrowth, ear cleanser products are commonly used. It is important therefore, to measure their antibiofilm effects. In this study, six ear cleansers (EpioticⓇ SIS, EpioticⓇ Advanced, CleanauralⓇ, OtifreeⓇ, PeptivetⓇ and SonotixⓇ) were evaluated against clinical isolates of Pseudomonas aeruginosa, methicillin resistant and sensitive Staphylococcus aureus and Staphylococcus pseudintermedius. Antibiofilm activity was measured using a colorimetric assay that detects viable cells through the reduction of thiazolyl blue tetrazolium bromide (MTT). Additionally, minimum inhibitory concentration (MIC) of Epiotic SIS and Epiotic Advanced were determined using a broth micro-dilution assay to assess their ability to inhibit bacteria in the planktonic state.ResultsEpiotic (SIS and Advanced), Cleanaural and Peptivet showed high antibiofilm activity, with Otifree and Sonotix showing moderate to low antibiofilm activity. Notably, Otifree was significantly less effective at inhibiting methicillin-resistant S. aureus compared to methicillin-sensitive strains. P. aeruginosa biofilms were less effectively disrupted by some ear cleansers, and the MIC results indicated that less diluted solutions were required to inhibit this isolate compared to the staphylococcal species. Differences in the antibacterial effects between Epiotic SIS and Epiotic Advanced solutions could also be detected from the MIC assays suggesting differences in formulations can affect antimicrobial efficacy.ConclusionsCommonly used canine ear cleanser products showed variable activity against multidrug resistant and sensitive Staphylococcus spp. and P. aeruginosa isolates in both biofilm and planktonic phases. The observed differences between bacterial strains and cleanser formulations highlight the importance of selecting appropriate products for targeted microbial control, which can lead to more effective management of chronic otitis externa and atopic dermatitis in dogs.

Formulation and evaluation of therapeutic antimicrobial citrus and Manuka honey creams with aloe vera, mint essential oil, and Indian costus

Honey has long been recognized for its antimicrobial properties, attributed to components such as polyphenols and biodefense proteins. Among honey types, Manuka honey, rich in methylglyoxal, and citrus honey, abundant in flavonoids and bioactive enzymes, exhibit potent antimicrobial activity. This study aims to enhance the antimicrobial and antibiofilm efficacy of Manuka and citrus honey by incorporating natural additives—aloe vera, Indian costus, and mint essential oil—into cream formulations. Two emulsion types, aerosil fumed silica-based and arabic gum-based, were prepared and optimized using sonication. The antimicrobial activity of these formulations was assessed against pathogenic bacteria, including Bacillus cereus, Pseudomonas aeruginosa, Salmonella enterica subsp. enterica serovar Typhimurium, Methicillin-resistant Staphylococcus aureus, Listeria monocytogenes, Micrococcus luteus, Escherichia coli O157:H7, and Klebsiella pneumoniae, as well as fungi such as Candida albicans and Aspergillus niger. The most effective formulations demonstrated inhibition zones of up to 28 mm against B. cereus and 24 mm against S. Typhimurium. Additionally, antibiofilm activity was evaluated using a 3D biofilm model, with formulations containing citrus honey and Indian costus or Manuka honey and aloe vera achieving biofilm reductions of 44.39% and 21.33%, respectively, against P. aeruginosa and MRSA. Furthermore, the composition of the citrus honey was analyzed using gas chromatography-mass spectrometry to identify the volatile and non-volatile compounds contributing to their antimicrobial properties. These findings suggest that honey-based formulations enhanced with natural additives hold significant potential for combating biofilm-associated infections.

3D-printed poly (lactic acid) scaffolds coated with cationic macro-biocide: Investigation of anti-biofilm activity and thermo-mechanical properties

In this study, the primary goal was to combine surface modification and 3D printing technology to create materials with anti-biofilm action. In order to achieve this, first a two-step reaction procedure using ring-opening copolymerization and copper(I)-catalyzed azide-alkyne cycloaddition click reaction was used to successfully fabricate poly (lactic acid) (PLA) bearing quaternary ammonium salt (QAS) as an antimicrobial agent on its backbone at rates of 5% by mole. Then, this synthesized PLA-based (co)polymer dissolved in acetone with a weight percentage of 30% was used to coat 3D-printed PLA by dipping for 10, 30, and 90 s. These coated samples encoded PLA/10/PLA-QAS, PLA/30/PLA-QAS, and PLA/90/PLA-QAS, respectively. The coated PLA scaffolds were then characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria were used to assess the anti-biofilm activity of the samples. In addition, the thermal and mechanical properties of the samples were examined through differential scanning calorimetry (DSC) and three-point bending tests, respectively. Consequently, covering the 3D-printed PLA surfaces with synthesized antimicrobial polymer prevented the formation of biofilms against both bacteria, and all coated samples showed no toxicity in 25% and 10% extraction mediums. And, it was observed that the antimicrobial polymer solution had a plasticizing effect on the PLA scaffold. As the dipping times increased, the glass transition temperatures of the coated samples decreased. In terms of flexural behaviors, increasing the dipping time also improved the flexural strain of coated PLA scaffolds. These thermo-mechanical results are correlated with SEM morphologies because of the penetration and solution effect of antimicrobial polymer dissolved in acetone.

Recent evidence on prominent anti-bacterial capacities of compounds derived from the mangosteen fruit.

Multi-drug resistant bacterial infections are of global concern, leading to staggering health care costs and loss of lives. Hence, novel therapeutic options are highly required. Garcinia mangostana, a plant known as mangosteen (also termed "queen of the fruits"), is said to possess a multitude of favorable features like anti-microbial capacity. Accordingly, we compiled a literature review addressing the potential of the mangosteen and its compounds for the treatment of bacterial infections. The included 23publications consistently reported the inhibition or elimination of bacteria following the administration of mangosteen extracts and compounds such as the xanthone α-mangostin, both in vitro and invivo. Even pathogens like methicillin-resistant Staphylococcus aureus as well as vancomycin-resistant Enterococcus species were tackled. While the effect of mangosteen extracts and compounds appeared to be dose-dependent, they exhibited also anti-biofilm activity and strong stability under varying conditions, suggesting suitability for a versatile approach to combat infectious diseases. Moreover, the combination of α-mangostin with other phytotherapeutic agents and especially antibiotics revealed enhanced anti-bacterial results, at low or no toxicity. In light of this review, we conclude that mangosteen extracts and compounds are promising candidates for the anti-bacterial therapy of human infections, warranting further consideration in clinical trials.

Design and synthesis of new 1,3,4-thiadiazoles as antimicrobial and antibiofilm agents.

This study assessed the invitro antibacterial and antibiofilm properties of new 1,3,4-thiadiazole derivatives. 1H NMR and 13C NMR analyses were employed to confirm the structure of the synthesized compounds, the characterization is followed by assessments of their efficacy against Bacillus subtilis NRRL B478, Staphylococcus aureus ATCC 29213, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, as well as for antifungal activity against Candida albicans ATCC 90028 and Candida krusei ATCC 6258, using the broth microdilution method. Notably, among the tested compounds, compound 4a exhibited the highest antimicrobial activity, with a minimal inhibitory concentration of 125 μg/mL against P.aeruginosa ATCC 27853 and significant antibiofilm activity, achieving 94 %, 98 % and 100 % biofilm inhibition at 250, 500 and 1,000 μg/mL, respectively. Besides, compound 4h achieved 81 %, 89 % and 98 % S.aureus ATCC 29213 biofilm inhibition at 250, 500 and 1,000 μg/mL, respectively, and displayed potent antibacterial activity against this bacterium. Finally, the theoretical ADME properties of the compounds 4a-4h were analyzed by calculations. This study has consolidated a base for the development of new antibacterial and antibiofilm agents and advanced our understanding of their potential mode of action against biofilm-associated infections.