Search

Bacterial biofilms and intracellular pathogens pose significant challenges in eradication, often leading to persistent infections that are difficult to treat. To address this issue, the hydrophobic biofilm dispersant D‐tyrosine is encapsulated within protein‐polycation nanoparticles, designed using a mannose‐terminated cationic polymer and concanavalin through electrostatic interactions. Thermodynamic studies reveal that free mannosyl groups on the nanoparticle surface promote spontaneous binding to receptor molecules mimicking those on bacterial biofilms and host cells. Under mildly acidic conditions, the nanoparticles reduce in size from 550 to ≈48 nm within 2 h, releasing 76% of encapsulated D‐tyrosine. The combination of mannose targeting, particle size reduction, and controlled D‐tyrosine release enable the nanoparticles to eliminate 70%–80% of the Pseudomonas aeruginosa and Staphylococcus aureus biofilm biomass at minimum bactericidal concentration (MBC) and 2MBC while eradicating 8 log of bacteria embedded within the biofilm. In an intracellular Pseudomonas aeruginosa infection model using RAW 264.7 macrophages, the nanoparticles at 2MBC eliminate over 95% of the intracellular bacteria without inducing an increase in the inflammatory cytokine interleukin‐6. These protein‐polycation nanoparticles, which activate their antimicrobial properties under acidic conditions, efficiently penetrate bacterial biofilms and host cell barriers via their mannose‐rich surface, offering a promising strategy for the treatment of persistent infections. [ABSTRACT FROM AUTHOR]

Endoscopic lung volume reduction (ELVR) using endobronchial valves (EBV) is a treatment option for a subset of patients with severe chronic obstructive pulmonary disease (COPD), suffering from emphysema and hyperinflation. In this pilot study, we aimed to determine the presence of bacterial biofilm infections on EBV and investigate their involvement in lack of clinical benefits, worsening symptomatology, and increased exacerbations that lead to the decision to remove EBVs. We analyzed ten COPD patients with ELVR who underwent EBV removal. Clinical data were compared to the microbiological findings from conventional EBV culture. In addition, EBV were analyzed by FISHseq, a combination of Fluorescence in situ hybridization (FISH) with PCR and sequencing, for visualization and identification of microorganisms and biofilms. All ten patients presented with clinical symptoms, including pneumonia and recurrent exacerbations. Microbiological cultures from EBV detected several microorganisms in all ten patients. FISHseq showed either mixed or monospecies colonization on the EBV, including oropharyngeal bacterial flora, Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus spp., and Fusobacterium sp. On 5/10 EBV, FISHseq visualized biofilms, on 1/10 microbial microcolonies, on 3/10 single microorganisms, and on 1/10 no microorganisms. The results of the study demonstrate the presence of biofilms on EBV for the first time and its potential involvement in increased exacerbations and clinical worsening in patients with ELVR. However, further prospective studies are needed to evaluate the clinical relevance of biofilm formation on EBV and appropriate treatment options to avoid infections in patients with ELVR. [ABSTRACT FROM AUTHOR]

Compared to traditional nanomedicines, micro/nanomotors offer significant advantages due to their autonomous movement capability, which provides a wider range of application possibilities. However, the complex barrier systems within the body, including cellular barriers, tissue barriers, and bacterial biofilm barriers, present significant obstacles. These biological barriers, ranging from the macroscopic to the microscopic level, hinder drugs from reaching their targets and exerting their effects through mechanisms of high selectivity and physical obstruction. Therefore, designing and optimizing micro/nanomotors to effectively traverse these biological barriers is a critical challenge in current research. This paper focuses on advancements in overcoming biological barriers using micro/nanomotors in the past five years, discussing the existing challenges and future research priorities. With continuous optimization by researchers, we believe that micro/nanomotors could pave the way for new therapeutic avenues by overcoming the biological barriers that traditional drugs cannot, thus providing more precise and effective solutions for clinical treatment. [ABSTRACT FROM AUTHOR]

Microneedles (MNs) have emerged as a promising transdermal antimicrobial delivery system, providing precise and localized drug delivery while complemented with noninvasiveness and patient compliance. Currently, the topical application of antimicrobials restricts the delivery of drugs to the critical areas of the wound bed, largely due to barriers posed by the necrotic tissue, scab formation, and bacterial biofilms, which severely diminish the bioavailability of the therapeutics. MNs have enabled efficient and targeted delivery to overcome many chronic wound challenges. Over the past decade, significant progress has been made to develop MNs with unique properties tailored for the delivery of vaccines, anticancer, and antimicrobials. As ongoing research continues to refine MN design, material properties, and drug formulations, the potential for revolutionizing antimicrobial drug delivery for efficacy, patient experience, and therapeutic outcomes remains at the forefront of scientific research. In this review, insights are provided into the latest progress, current developments, and the diverse applications of MNs for antimicrobial drug delivery. Herein, the translational potential of MNs is highlighted and a perspective on the current challenges associated with clinical translation is provided. Furthermore, this review aids in identifying research gaps while empowering and contributing to the future implementation of cutting‐edge delivery systems to effectively tackle antimicrobial resistance. [ABSTRACT FROM AUTHOR]

The risk of colorectal cancer [CRC] is increased in patients with inflammatory bowel disease [IBD], particularly in extensive ulcerative colitis [UC] and Crohn's colitis. Gut microbiota have been implicated in the pathogenesis of CRC via multiple mechanisms, including the release of reactive oxygen species and genotoxins, and induction of inflammation, as well as activation of the immune response. Gut microbiota can enhance their carcinogenic and proinflammatory properties by organising into biofilms, potentially making them more resistant to the host's immune system and to antibiotics. Colonic biofilms have the capacity to invade colonic tissue and accelerate tumorigenesis in tumour-prone models of mice. In the context of IBD, the prevalence of biofilms has been estimated to be up to 95%. Although the relationship between chronic inflammation and molecular mediators that contribute to IBD-associated CRC is well established, the role of gut microbiota and biofilms in this sequence is not fully understood. Because CRC can still arise in the absence of histological inflammation, there is a growing interest in identifying chemopreventive agents against IBD-associated CRC. Commonly used in the treatment of UC, 5-aminosalicylates have antimicrobial and anticarcinogenic properties that might have a role in the chemoprevention of CRC via the inhibition or modulation of carcinogenic gut microbiota and potentially of biofilm formation. Whether biologics and other IBD-targeted therapies can decrease the progression towards dysplasia and CRC, via mechanisms independent of inflammation, is still unknown. Further research is warranted to identify potential new microbial targets in therapy for chemoprevention of dysplasia and CRC in IBD. [ABSTRACT FROM AUTHOR]

This research explores the use of the pepN activity fluorescent sensor DCM-Ala in bacterial biofilms, emphasizing its significance due to the critical role of biofilms in various biological processes. Advanced imaging techniques were employed to visualize pepN activity, introducing a novel approach to examining biofilm maturity. We found that the overexpression of pepN increases the ability of E. coli to form biofilm. The findings demonstrate varying levels of pepN activity throughout biofilm development, suggesting potential applications in biofilm research and management. The results indicate that the fluorescent emission from this sensor could serve as a reliable indicator of biofilm maturity, and the imaging techniques developed could enhance our understanding and control of biofilm-related processes. This work highlights the importance of innovative methods in biofilm study and opens new avenues for utilizing chemical emissions in biofilm management. [ABSTRACT FROM AUTHOR]

Abstract Endoscopic lung volume reduction (ELVR) using endobronchial valves (EBV) is a treatment option for a subset of patients with severe chronic obstructive pulmonary disease (COPD), suffering from emphysema and hyperinflation. In this pilot study, we aimed to determine the presence of bacterial biofilm infections on EBV and investigate their involvement in lack of clinical benefits, worsening symptomatology, and increased exacerbations that lead to the decision to remove EBVs. We analyzed ten COPD patients with ELVR who underwent EBV removal. Clinical data were compared to the microbiological findings from conventional EBV culture. In addition, EBV were analyzed by FISHseq, a combination of Fluorescence in situ hybridization (FISH) with PCR and sequencing, for visualization and identification of microorganisms and biofilms. All ten patients presented with clinical symptoms, including pneumonia and recurrent exacerbations. Microbiological cultures from EBV detected several microorganisms in all ten patients. FISHseq showed either mixed or monospecies colonization on the EBV, including oropharyngeal bacterial flora, Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus spp., and Fusobacterium sp. On 5/10 EBV, FISHseq visualized biofilms, on 1/10 microbial microcolonies, on 3/10 single microorganisms, and on 1/10 no microorganisms. The results of the study demonstrate the presence of biofilms on EBV for the first time and its potential involvement in increased exacerbations and clinical worsening in patients with ELVR. However, further prospective studies are needed to evaluate the clinical relevance of biofilm formation on EBV and appropriate treatment options to avoid infections in patients with ELVR.

The emerging threat of antibiotic resistance and the formation of resilient biofilms pose a challenge to contemporary healthcare systems. This review dives into the interplay between antibiotic resistance mechanisms and biofilm production. Many pathogenic bacteria have an inherent ability of adhering tightly to a surface forming a complex matrix of extracellular polymeric substances (EPS) surrounding their cells. This is called a biofilm which allows pathogenic bacteria to survive in unsuitable environment. The adaptive nature of biofilms provides a protective shield against conventional antimicrobial agents, promoting chronic infections and complicating medical interventions. This phenomenon further adds to the ever-increasing problem of antibiotic resistance. Thus, there is an immediate necessity in developing novel strategies to deal with bacterial biofilms. In terms of human health, biofilms can be formed on mucosal surfaces and on surfaces of medical equipment. They are also a major reason for causing ‘biofouling’. Different approaches have been undertaken to counteract the menace of biofilms encompassing physical, chemical as well as biological methods. However, recent studies have shown that natural bioactive compounds found in fungal extracts, which has already been gaining attention due to their various properties like immunomodulatory activity, anti-tumor activity, antimicrobial activity etc., have the ability to prevent the formation as well as viability of biofilms through numerous mechanisms. This article thus explores the nuances of biofilm formation and its effects, and further delves deep into the convincing potential of the different components in fungal extracts against bacterial biofilms.

Oral Veillonella species are among the early colonizers of the human oral cavity. We constructed a small, single-selectable-marker shuttle plasmid, examined its ability to be transformed into diverse oral Veillonella strains, and assessed its potential use for expressing a gene encoding an oxygen-independent fluorescent protein, thus generating a fluorescent Veillonella parvula strain. Because tetracycline resistance is common in Veillonella , we replaced genes encoding ampicillin- and tetracycline-resistance in a previously described shuttle plasmid (pBSJL2) with a chloramphenicol acetyltransferase gene. The resulting plasmid pCF1135 was successfully introduced into four strains representing V. parvula and V. atypica by either natural transformation or electroporation. We then modified this plasmid to express a gene encoding an oxygen-independent fluorescent protein in V. parvula SKV38. The resulting strain yielded a fluorescence signal intensity ∼16 times higher than the wild type in microplate-based fluorimetry experiments. While fluorescence microscopy demonstrated that planktonic cells, colonies, and biofilms of fluorescent V. parvula could also be imaged, photobleaching was a significant issue. In conclusion, we anticipate this genetic system and information provided here will facilitate expanded studies of oral Veillonella species' properties and behavior. [ABSTRACT FROM AUTHOR]

Antimicrobial phototherapy has gained recognition as a promising approach for addressing bacterial biofilms, however, its effectiveness is often impeded by the robust physical and chemical defenses of the biofilms. Traditional antibacterial nanoplatforms face challenges in breaching the extracellular polymeric substances barrier to efficiently deliver photosensitizers deep into biofilms. Moreover, the prevalent hypoxia within biofilms restricts the success of oxygen-reliant phototherapy. In this study, we engineered a soft mesoporous organosilica nanoplatform (SMONs) by incorporating polyethylene glycol (PEG), catalase (CAT), and indocyanine green (ICG), forming SMONs-PEG-CAT-ICG (SPCI). We compared the antimicrobial efficacy of SPCI with more rigid nanoplatforms. Our results demonstrated that unique flexible mechanical properties of SPCI enable it to navigate through biofilm barriers, markedly enhancing ICG penetration in methicillin-resistant Staphylococcus aureus (MRSA) biofilms. Notably, in a murine subcutaneous MRSA biofilm infection model, SPCI showed superior biofilm penetration and pharmacokinetic benefits over its rigid counterparts. The embedded catalase in SPCI effectively converts excess H 2 O 2 present in infected tissues into O 2 , alleviating hypoxia and significantly boosting the antibacterial performance of phototherapy. Both in vitro and in vivo experiments confirmed that SPCI surpasses traditional rigid nanoplatforms in overcoming biofilm barriers, offering improved treatment outcomes for infections associated with bacterial biofilms. This study presents a viable strategy for managing bacterial biofilm-induced diseases by leveraging the unique attributes of a soft mesoporous organosilica-based nanoplatform. This research introduces an innovative antimicrobial phototherapy soft nanoplatform that overcomes the inherent limitations posed by the protective barriers of bacterial biofilms. By soft nanoplatform with flexible mechanical properties, we enhance the penetration and delivery of photosensitizers into biofilms. The inclusion of catalase within this soft nanoplatform addresses the hypoxia in biofilms by converting hydrogen peroxide into oxygen in infected tissues, thereby amplifying the antibacterial effectiveness of phototherapy. Compared to traditional rigid nanoplatforms, this flexible nanoplatform not only promotes the delivery of therapeutic agents but also sets a new direction for treating bacterial biofilm infections, offering significant implications for future antimicrobial therapies. [Display omitted] [ABSTRACT FROM AUTHOR]

Controlling the growth of bacterial biofilms in a specific pattern greatly enhances the study of cell‐to‐cell interactions and paves the way for expanding their biological applications. However, the development of simple, cost‐effective, and highly resolved biopatterning approaches remains a persistent challenge. Herein, a pioneering photodynamic biopatterning technique for the creation of living bacterial biofilms with customized geometries at high resolutions is presented. First of all, an outstanding aggregation‐induced emission photosensitizer is synthesized to enable efficient photodynamic bacterial killing at a low concentration. By combining with custom‐designed photomasks featuring both opaque and transparent patterns, the viability of photosensitizer‐coated bacteria is successfully manipulated by controlling the degree of light transmittance. This process leads to the formation of living bacterial biofilms with specific patterns replicated from the photomask. Such an innovative strategy can be employed to generate living bacterial biofilms composed of either mono‐ or multispecies, with a spatial resolution of approximately 24 µm. Furthermore, its potential applications in information storage/encryption and antibiotic screening are explored. This study provides an alternative way to understand and investigate the intricate interactions among bacteria within 3D biofilms, holding great promise in the controlled fabrication of dynamic biological systems for advanced applications. [ABSTRACT FROM AUTHOR]

In this study, UHPLC-HRMS analysis of the defatted methanol extract obtained from Inula salicina L. led to the identification of 58 compounds—hydroxycinnamic and hydroxybenzoic acids and their glycosides, acylquinic and caffeoylhexaric acids, and flavonoids and their glycosides. In addition, a new natural compound, N-(8-methylnepetin)-3-hydroxypiperidin-2-one was isolated and its structure was elucidated by NMR spectroscopy. The presence of a flavoalkaloid in genus Inula is described now for the first time. Chlorogenic acid was the main compound followed by 3,5-, 1,5- and 4,5-dicaffeoylquinic acids. The methanol extract was studied for its antioxidant potential by DPPH, ABTS, and FRAP assays and sun protective properties. In addition, a study was conducted to assess the effectiveness of the tested extract in inhibiting biofilm formation by Gram-positive and Gram-negative strains. Results from crystal violet tests revealed a notable decrease in biofilm mass due to the extract. The anti-biofilm efficacy was confirmed through the observation of the biofilm viability by live/dead staining. The obtained results showed that this plant extract could be used in the development of cosmetic products with antibacterial and sun protection properties. [ABSTRACT FROM AUTHOR]

Recently, there has been increasing evidence that many infections are associated with the formation of multispecies biofilms, in which there is a change in the sensitivity of bacteria to antibiotics and a change in the permeability of the extracellular matrix compared to monocultures. In this work, we show that the addition of cell-free culture liquid (CFCL) of Staphylococcus aureus to Klebsiella pneumoniae and Pseudomonas aeruginosa biofilms increases the content of α-, and β-polysaccharides in the matrix up to 2 times, which likely affects the structure of the biofilm. The increase in the polysaccharide component is also confirmed by a significant rise in the expression level of the K. pneumoniaepgaA and P. aeruginosapelA, pslA genes in the presence of S. aureus culture liquid. [ABSTRACT FROM AUTHOR]

Microneedles (MNs) have emerged as a promising transdermal antimicrobial delivery system, providing precise and localized drug delivery while complemented with noninvasiveness and patient compliance. Currently, the topical application of antimicrobials restricts the delivery of drugs to the critical areas of the wound bed, largely due to barriers posed by the necrotic tissue, scab formation, and bacterial biofilms, which severely diminish the bioavailability of the therapeutics. MNs have enabled efficient and targeted delivery to overcome many chronic wound challenges. Over the past decade, significant progress has been made to develop MNs with unique properties tailored for the delivery of vaccines, anticancer, and antimicrobials. As ongoing research continues to refine MN design, material properties, and drug formulations, the potential for revolutionizing antimicrobial drug delivery for efficacy, patient experience, and therapeutic outcomes remains at the forefront of scientific research. In this review, insights are provided into the latest progress, current developments, and the diverse applications of MNs for antimicrobial drug delivery. Herein, the translational potential of MNs is highlighted and a perspective on the current challenges associated with clinical translation is provided. Furthermore, this review aids in identifying research gaps while empowering and contributing to the future implementation of cutting‐edge delivery systems to effectively tackle antimicrobial resistance.

Jian Yu,1,2,* Huan Xu,1,2,* Jiaojiao Wei,1,2 Liangliang Niu,1,2 Haohao Zhu,1,3 Chunhui Jiang1,2 1Department of Ophthalmology and Visual Science, Eye, Ear, Nose and Throat Hospital, Shanghai Medical College of Fudan University, Shanghai, People’s Republic of China; 2Key Laboratory of Myopia of State Health Ministry and Key Laboratory of Visual Impairment and Restoration of Shanghai, Shanghai, People’s Republic of China; 3Department of Ophthalmology, Shanghai Fifth People’s Hospital, Fudan University, Shanghai, People’s Republic of China*These authors contributed equally to this workCorrespondence: Chunhui Jiang, Department of Ophthalmology and Vision Science, Eye and ENT Hospital, Fudan University, 83 Fenyang Road, Shanghai, 200031, People’s Republic of China, Email chhjiang70@163.com Haohao Zhu, Department of Ophthalmology, Shanghai Fifth People’s Hospital, Fudan University, 128 Ruili Road, Shanghai, 200240, People’s Republic of China, Tel +86-21-64308151, Fax +86-21-64300477, Email haohao700315@163.comBackground: Bacterial endophthalmitis is an acute progressive visual threatening disease and one of the most important causes of blindness worldwide. Current treatments are unsatisfactory due to the emergence of drug-resistant bacteria and the formation of biofilm.Purpose: The aim of our research was to construct a novel nano-delivery system with better antimicrobial and antibiofilm effects.Methods: This study developed a novel antibiotic nanoparticle delivery system (MXF@UiO-UBI-PEGTK), which is composed of (i) moxifloxacin (MXF)-loaded UiO-66 nanoparticle as the core, (ii) bacteria-targeting peptide ubiquicidin (UBI29-41) immobilized on UiO-66, and (iii) ROS-responsive poly (ethylene glycol)-thioketal (PEG-TK) as the surface shell. Then the important properties of the newly developed delivery system, including biocompatibility, toxicity, release percentage, thermal stability, ability of targeting bacteria, and synergistic antibacterial effects on bacterial biofilms and endophthalmitis, were evaluated.Results: In vitro, MXF@UiO-UBI-PEGTK exhibited significant antibiotic effects including the excellent antibiofilm property against Staphylococcus aureus, Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus at high levels of ROS. Moreover, MXF@UiO-UBI-PEGTK demonstrated outstanding efficacy in treating bacterial endophthalmitis in vivo.Conclusion: This novel nanoparticle delivery system with ROS-responsive and bacteria-targeted properties promotes the precise and effective release of drugs and has significant potential for clinical application of treating bacterial endophthalmitis. Keywords: endophthalmitis, nanoparticles, bacterial biofilms, ROS-responsive, moxifloxacin

ABSTRACTBacterial biofilms have attracted significant attention due to their involvement in persistent infections, food and water contamination, and infrastructure corrosion. This review delves into the intricate interactions between bacterial biofilms and unicellular parasites, shedding light on their impact on biofilm formation, structure, and function. Unicellular parasites, including protozoa, influence bacterial biofilms through grazing activities, leading to adaptive changes in bacterial communities. Moreover, parasites like Leishmania and Giardia can shape biofilm composition in a grazing independent manner, potentially influencing disease outcomes. Biofilms, acting as reservoirs, enable the survival of protozoan parasites against environmental stressors and antimicrobial agents. Furthermore, these biofilms may influence parasite virulence and stress responses, posing challenges in disease treatment. Interactions between unicellular parasites and fungal-containing biofilms is also discussed, hinting at complex microbial relationships in various ecosystems. Understanding these interactions offers insights into disease mechanisms and antibiotic resistance dissemination, paving the way for innovative therapeutic strategies and ecosystem-level implications.

Background: Although there is still disagreement on the microbiological profile, bacteria in the peri-implant area are responsible for the development of peri-implantitis (PI). Methodology: After 14 unsuccessful implants were extracted, they were immediately prepared for scanning electron microscope examination. Three equally distributed subcrestal levels of the exposed area were used to photograph the dental implants. Three inspectors recognised and measured the different bacterial morphotypes. Results: In our research, the implants showed evidence of diverse bacterial morphotypes that were unrelated to the development of the disease. Filaments dominated several implants, while combinations of cocci/rods or spirilles/spirochetes were seen in several. Overall, the morphologic biofilm makeup of all devices varied. Conclusion: Although there were notable variations amongst the implants, identical morphological types in each implant were frequently observed over the whole region. [ABSTRACT FROM AUTHOR]

Infections associated with biofilm formation by gram-positive and gram-negative microorganisms cause difficulty in therapy and are prone to transition into chronic forms. Approaches to degradation of the biofilm matrix are therefore in demand. In the present work, we show that recombinant PAPC serine protease from Aspergillus ochraceus were able to degrade mature biofilms formed by a number of gram-positive and gram-negative bacteria by 15‒20% at 50 µg/mL. At 100 µg/mL, the biomass of S. aureus and P. aeruginosa biofilms decreased by 50%. Thus, the PAPC may be a promising agent for biofilm removal and enhance the efficiency of antimicrobial therapy. [ABSTRACT FROM AUTHOR]

With the increasing incidence of diverse global bacterial outbreaks, it is important to build an immutable decentralized database that can capture regional changes in bacterial resistance with time. Herein, we investigate the use of a rapid 3D printed µbiochamber with a laser-ablated interdigitated electrode developed for biofilm analysis of Pseudomonas aeruginosa, Acinetobacter baumannii and Bacillus subtilis using electrochemical biological impedance spectroscopy (EBIS) across a 48 h spectrum, along with novel ladder-based minimum inhibitory concentration (MIC) stencil tests against oxytetracycline, kanamycin, penicillin G and streptomycin. Furthermore, in this investigation, a search query database has been built demonstrating the deterministic nature of the bacterial strains with real and imaginary impedance, phase, and capacitance, showing increased bacterial specification selectivity in the 9772.37 Hz range. [ABSTRACT FROM AUTHOR]

Host immune systems serving as crucial defense lines are vital resisting mechanisms against biofilm‐associated implant infections. Nevertheless, biofilms hinder the penetration of anti‐bacterial species, inhibit phagocytosis of immune cells, and frustrate host inflammatory responses, ultimately resulting in the weakness of the host immune system for biofilm elimination. Herein, a cell‐like construct is developed through encapsulation of erythrocyte membrane fragments on the surface of Fe3O4 nanoparticle‐fabricated microbubbles and then loaded with hydroxyurea (EMB‐Hu). Under ultrasound (US) stimulation, EMB‐Hu undergoes a stable oscillation manner to act in an "exocytosis" mechanism for disrupting biofilm, releasing agents, and enhancing penetration of catalytically generated anti‐bacterial species within biofilms. Additionally, the US‐stimulated "exocytosis" by EMB‐Hu can activate pro‐inflammatory macrophage polarization and enhance macrophage phagocytosis for clearance of disrupted biofilms. Collectively, this work has exhibited cell‐like microbubbles with US‐stimulated "exocytosis" mechanisms to overcome the biofilm barrier and signal macrophages for inflammatory activation, finally achieving favorable therapeutic effects against implant infections caused by methicillin‐resistant Staphylococcus aureus (MRSA) biofilms. [ABSTRACT FROM AUTHOR]

The increase in bacterial resistance to antibiotics in recent years demands innovative strategies for the detection and combating of biofilms, which are notoriously resilient. Biofilms, particularly those on contact lenses, can lead to biofilm-related infections (e.g., conjunctivitis and keratitis), posing a significant risk to patients. Non-destructive and non-contact sensing techniques are essential in addressing this threat. Digital holographic tomography emerges as a promising solution. This allows for the 3D reconstruction of the refractive index distribution in biological samples, enabling label-free visualization and the quantitative analysis of biofilms. This tool provides insight into the dynamics of biofilm formation and maturation on the surface of transparent materials. Applying digital holographic tomography for biofilm examination has the potential to advance our ability to combat the antibiotic bacterial resistance crisis. A recent study focused on characterizing biofilm formation and maturation on six soft contact lens materials (three silicone hydrogels, three hydrogels), with a particular emphasis on Staphylococcus epidermis and Pseudomonas aeruginosa, both common culprits in ocular infections. The results revealed species- and time-dependent variations in the refractive indexes and volumes of biofilms, shedding light on cell dynamics, cell death, and contact lens material-related factors. The use of digital holographic tomography enables the quantitative analysis of biofilm dynamics, providing us with a better understanding and characterization of bacterial biofilms. [ABSTRACT FROM AUTHOR]

Bacterial biofilms (BBFs) exhibit high drug resistance, antiphagocytosis, and extremely strong adhesion, and therefore can cause various diseases. They are also one of the important causes of bacterial infections. Thus, the effective removal of BBFs has attracted considerable research interest. Endolysins, which are efficient antibacterial bioactive macromolecules, have recently been receiving increasing attention. In this study, we overcame the deficiencies of endolysins via immobilization on chitosan nanoparticles (CS-NPs) by preparing LysST-3-CS-NPs using the ionic cross-linking reaction between CS-NPs and LysST-3, an endolysin purified using phage ST-3 expression. The obtained LysST-3-CS-NPs were verified and thoroughly characterized, their antimicrobial activity was investigated using microscopy, and their antibacterial efficacy on polystyrene surfaces was studied. The results obtained suggested that LysST-3-CS-NPs exhibit enhanced bactericidal properties and increased stability and can serve as reliable biocontrol agents for the prevention and treatment of Salmonella biofilm infections. [ABSTRACT FROM AUTHOR]

Abstract Controlling the growth of bacterial biofilms in a specific pattern greatly enhances the study of cell‐to‐cell interactions and paves the way for expanding their biological applications. However, the development of simple, cost‐effective, and highly resolved biopatterning approaches remains a persistent challenge. Herein, a pioneering photodynamic biopatterning technique for the creation of living bacterial biofilms with customized geometries at high resolutions is presented. First of all, an outstanding aggregation‐induced emission photosensitizer is synthesized to enable efficient photodynamic bacterial killing at a low concentration. By combining with custom‐designed photomasks featuring both opaque and transparent patterns, the viability of photosensitizer‐coated bacteria is successfully manipulated by controlling the degree of light transmittance. This process leads to the formation of living bacterial biofilms with specific patterns replicated from the photomask. Such an innovative strategy can be employed to generate living bacterial biofilms composed of either mono‐ or multispecies, with a spatial resolution of approximately 24 µm. Furthermore, its potential applications in information storage/encryption and antibiotic screening are explored. This study provides an alternative way to understand and investigate the intricate interactions among bacteria within 3D biofilms, holding great promise in the controlled fabrication of dynamic biological systems for advanced applications.

Background: The novel bacterial topoisomerase inhibitors (NBTIs) developed in our laboratory show potent on-target enzyme inhibition but suffer from low activity against Gram-negative bacteria. Methods: With the aim of improving the antibacterial activity of our compounds against Gram-negative bacteria, we tested them in combination with different efflux pump inhibitors (EPIs), a strategy that showed promise in several other classes of antimicrobials. We also investigated the combined effect of NBTIs with ATP-competitive inhibitors of bacterial type II topoisomerases (ACIs), as well as the antibiofilm properties of our compounds and the combination with EPIs against early and mature Acietobacter baumannii biofilm. Results: Our results demonstrate that combinations of NBTIs with EPI Phenylalanine-arginyl-β-naphthylamide significantly reduce the corresponding NBTIs’ minimal inhibitory concentration values and show potentiation of A. baumannii biofilm inhibition as compared to NBTIs alone. Although combinations of NBITs and ACIs did not show synergistic effects, the FIC index value calculations revealed additive effects for all the combinations of a selected NBTI in combination with three ACIs in all the assayed Gram-negative bacteria from the ESKAPE group. Conclusions: These results show for the first time that combinations of NBTIs with either EPIs or a different class of the topoisomerase inhibitors may be a beneficial strategy to combat difficult-to-treat bacterial infections.

This research explores the use of the pepN activity fluorescent sensor DCM-Ala in bacterial biofilms, emphasizing its significance due to the critical role of biofilms in various biological processes. Advanced imaging techniques were employed to visualize pepN activity, introducing a novel approach to examining biofilm maturity. We found that the overexpression of pepN increases the ability of E. coli to form biofilm. The findings demonstrate varying levels of pepN activity throughout biofilm development, suggesting potential applications in biofilm research and management. The results indicate that the fluorescent emission from this sensor could serve as a reliable indicator of biofilm maturity, and the imaging techniques developed could enhance our understanding and control of biofilm-related processes. This work highlights the importance of innovative methods in biofilm study and opens new avenues for utilizing chemical emissions in biofilm management.

Bacterial extracellular DNA (eDNA) is important for the development of virtually all biofilms, their architecture, and their resistance to host defense. DNase I and DNase1L3 are important host immune strategies to prevent biofilm formation. eDNA in biofilms can adopt a Z-form, an alternative configuration of DNA that increases biofilm rigidity and is maintained by DNA-binding proteins. Z-DNA is resistant to DNase I, suggesting that bacteria have learned to circumvent certain host innate immune strategies by changing their eDNA physical form. DNA sensors cGAS/STING are involved in immune responses against Porphyromonas gingivalis biofilms in periodontitis and in the vicious cycle that maintains dysbiotic microbiota and chronic intestinal inflammation in IBD suggesting a role in recognizing eDNA in biofilms. eDNA-binding proteins are essential for biofilm integrity and eDNA/protein complexes are pathogen-associated molecular patterns (PAMPs) recognized by pattern recognition receptors (PRRs) like Toll-like receptors (TLRs). Many reports support the working hypothesis that eDNA is a universal biofilm-associated PAMP and that targeting eDNA might represent a novel therapeutic strategy against recurrent/chronic bacterial infections that generate biofilms. Identifying the role of extracellular DNA in mammalian immune recognition of biofilms can improve our understanding of innate immune responses to bacterial infections; it may also help in the discovery of novel therapeutic targets against certain chronic/recurrent/antibiotic-resistant infections and autoimmunity. Historically, the study of innate immune detection of bacterial infections has focused on the recognition of pathogen-associated molecular patterns (PAMPs) from bacteria growing as single cells in planktonic phase. However, over the past two decades, studies have highlighted an adaptive advantage of bacteria: the formation of biofilms. These structures are complex fortresses that stand against a hostile environment, including antibiotics and immune responses. Extracellular DNA (eDNA) is a crucial component of the matrix of most known biofilms. In this opinion article, I propose that eDNA is a universal PAMP that the immune system uses to recognize biofilms. Outstanding questions concern the discrimination between biofilm-associated eDNA and DNA from planktonic bacteria, the innate receptors involved, and the immune response to biofilms. [ABSTRACT FROM AUTHOR]

The resistance of biofilms to antibiotics is a key factor that makes bacterial infections unsusceptible to antimicrobial therapy. The results of classical tests of cell sensitivity to antibiotics cannot be used to predict therapeutic success in infections associated with biofilm formation. We describe a simple and rapid method for the real-time evaluation of bacterial biofilm sensitivity to antibiotics, with Pseudomonas putida and ampicillin as examples. The method uses an electric biosensor to detect the difference between changes in the biofilm electric polarizability, thereby evaluating antibiotic sensitivity. The electric signals showed that P. putida biofilms were susceptible to ampicillin and that at high antibiotic concentrations, the biofilms differed markedly in their susceptibility (dose-dependent effect). The sensor also detected differences between biofilms before and after ampicillin treatment. The electric-signal changes enabled us to describe the physical picture of the processes occurring in bacterial biofilms in the presence of ampicillin. The approach used in this study is promising for evaluating the activity of various compounds against biofilms, because it permits a conclusion about the antibiotic sensitivity of biofilm bacteria to be made in real time and in a short period (analysis time, not longer than 20 min). An added strong point is that analysis can be done directly in liquid, without preliminary sample preparation. Key points: • Sensor system to analyze biofilm antimicrobial susceptibility is described. • The signal change depended on the ampicillin concentration (dose-dependent effect). • The sensor allows real-time determination of the antibiofilm effect of ampicillin. [ABSTRACT FROM AUTHOR]

Campylobacter concisus is a bacterium that inhabits human oral cavities and is an emerging intestinal tract pathogen known to be a biofilm producer and one of the bacterial species found in dental plaque. In this study, biofilms of oral and intestinal C. concisus isolates were phenotypically characterized. The role of the luxS gene, which is linked to the regulation of biofilm formation in other pathogens, was assessed in relation to the pathogenic potential of this bacterium. Biofilm formation capacity was assessed using phenotypic assays. Oral strains were shown to be the highest producers. A luxS mutant was created by inserting a kanamycin cassette within the luxS gene of the highest biofilm-forming isolate. The loss of the polar flagellum was observed with scanning and transmission electron microscopy (SEM and TEM). Furthermore, the luxS mutant exhibited a significant reduction (p < 0.05) in biofilm formation, motility, and its expression of flaB, in addition to the capability to invade intestinal epithelial cells, compared to the parental strain. The study concluded that C. concisus oral isolates are significantly higher biofilm producers than the intestinal isolates and that LuxS plays a role in biofilm formation, invasion, and motility in this bacterium. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa can cause a wide array of chronic and acute infections associated with its ability to rapidly switch between planktonic, biofilm, and dispersed lifestyles, each with a specific arsenal for bacterial survival and virulence. At the cellular level, many of the physiological transitions are orchestrated by the intracellular second messenger c-di-GMP and its receptor-effector FleQ. A bacterial enhancer binding protein, FleQ acts as a master regulator of both flagellar motility and adherence factor secretion and uses remarkably different transcription activation mechanisms depending on its dinucleotide loading state, adenosine triphosphatase (ATPase) activity, interactions with polymerase sigma (s) factors, and complexation with a second ATPase, FleN. How the FleQ-FleN tandem can exert diverse effects through recognition of a conserved FleQ binding consensus has remained enigmatic. Here, we provide cryogenic electron microscopy (cryo-EM) structures of both c-di-GMP-bound and c-di-GMP-free FleQ-FleN complexes which deepen our understanding of the proteins' (di)nucleotide-dependent conformational switching and fine-tuned roles in gene expression regulation. [ABSTRACT FROM AUTHOR]

In the presence of orthopedic implants, opportunistic pathogens can easily colonize the biomaterial surfaces, forming protective biofilms. Life in biofilm is a central pathogenetic mechanism enabling bacteria to elude the host immune response and survive conventional medical treatments. The formation of mature biofilms is universally recognized as the main cause of septic prosthetic failures. Neutrophils are the first leukocytes to be recruited at the site of infection. They are highly efficient in detecting and killing planktonic bacteria. However, the interactions of these fundamental effector cells of the immune system with the biofilm matrix, which is the true interface of a biofilm with the host cells, have only recently started to be unveiled and are still to be fully understood. Biofilm matrix macromolecules consist of exopolysaccharides, proteins, lipids, teichoic acids, and the most recently described extracellular DNA. The latter can also be stolen from neutrophil extracellular traps (NETs) by bacteria, who use it to strengthen their biofilms. This paper aims to review the specific interactions that neutrophils develop when they physically encounter the matrix of a biofilm and come to interact with its polymeric molecular components. [ABSTRACT FROM AUTHOR]

Despite advancements in our knowledge of neutrophil responses to planktonic bacteria during acute inflammation, much remains to be elucidated on how neutrophils deal with bacterial biofilms in implant infections. Further complexity transpires from the emerging findings on the role that biomaterials play in conditioning bacterial adhesion, the variety of biofilm matrices, and the insidious measures that biofilm bacteria devise against neutrophils. Thus, grasping the entirety of neutrophil–biofilm interactions occurring in periprosthetic tissues is a difficult goal. The bactericidal weapons of neutrophils consist of the following: ready-to-use antibacterial proteins and enzymes stored in granules; NADPH oxidase-derived reactive oxygen species (ROS); and net-like structures of DNA, histones, and granule proteins, which neutrophils extrude to extracellularly trap pathogens (the so-called NETs: an allusive acronym for "neutrophil extracellular traps"). Neutrophils are bactericidal (and therefore defensive) cells endowed with a rich offensive armamentarium through which, if frustrated in their attempts to engulf and phagocytose biofilms, they can trigger the destruction of periprosthetic bone. This study speculates on how neutrophils interact with biofilms in the dramatic scenario of implant infections, also considering the implications of this interaction in view of the design of new therapeutic strategies and functionalized biomaterials, to help neutrophils in their arduous task of managing biofilms. [ABSTRACT FROM AUTHOR]

Antimicrobial photoinactivation (API) has shown some promise in potentially treating different nosocomial bacterial infections, however, its application on staphylococci, especially other than Staphylococcus aureus or methicillin-resistant S. aureus (MRSA) species is still limited. Although S. aureus is a well-known and important nosocomial pathogen, several other species of the genus, particularly coagulase-negative Staphylococcus (CNS) species such as Staphylococcus epidermidis and Staphylococcus saprophyticus, can also cause healthcare-associated infections and foodborne intoxications. CNS are often involved in resilient biofilm formation on medical devices and can cause infections in patients with compromised immune systems or those undergoing invasive procedures. In this study, the effects of chlorophyllin and riboflavin-mediated API on S. epidermidis and S. saprophyticus planktonic cells and biofilm are demonstrated for the first time. Based on the residual growth determination and metabolic reduction ability changes, higher inactivating efficiency of chlorophyllin-mediated API was determined against the planktonic cells of both tested species of bacteria and against S. saprophyticus biofilm. Some insights on whether aqueous solutions of riboflavin and chlorophyllin, when illuminated with optimal exciting wavelength (440 nm and 402 nm, respectively) generate O2−•, are also provided in this work.

Abstract Host immune systems serving as crucial defense lines are vital resisting mechanisms against biofilm‐associated implant infections. Nevertheless, biofilms hinder the penetration of anti‐bacterial species, inhibit phagocytosis of immune cells, and frustrate host inflammatory responses, ultimately resulting in the weakness of the host immune system for biofilm elimination. Herein, a cell‐like construct is developed through encapsulation of erythrocyte membrane fragments on the surface of Fe3O4 nanoparticle‐fabricated microbubbles and then loaded with hydroxyurea (EMB‐Hu). Under ultrasound (US) stimulation, EMB‐Hu undergoes a stable oscillation manner to act in an “exocytosis” mechanism for disrupting biofilm, releasing agents, and enhancing penetration of catalytically generated anti‐bacterial species within biofilms. Additionally, the US‐stimulated “exocytosis” by EMB‐Hu can activate pro‐inflammatory macrophage polarization and enhance macrophage phagocytosis for clearance of disrupted biofilms. Collectively, this work has exhibited cell‐like microbubbles with US‐stimulated “exocytosis” mechanisms to overcome the biofilm barrier and signal macrophages for inflammatory activation, finally achieving favorable therapeutic effects against implant infections caused by methicillin‐resistant Staphylococcus aureus (MRSA) biofilms.

Staphylococcal biofilms are an important virulence factor that allows for effective infectious effects and colonization of the animal body. This study was devoted to the evaluation of the biofilm forming ability of different strains of Staphylococcus pseudintermedius and Staphylococcus aureus isolated from animals in Ukraine. In addition, the presence of extracellular adhesin genes icaA and icaD in S. pseudintermedius strains was determined. The density of the biofilms was determined by culturing microorganisms in 96-well plates and staining the resulting structures with crystal violet. The genes responsible for biofilm formation were identified by classical polymerase chain reaction (PCR) using primers selected from the literature. The data obtained from this study showed a direct correlation between the density of the biofilm and the number of viable cells involved in its formation. Thus, 23.1% of S. pseudintermedius strains and 25% of S. aureus strains isolated from dogs demonstrated the ability to form a dense biofilm, while 46.2% of S. pseudintermedius strains and 50% of S. aureus strains formed a weak biofilm. The origin of the isolates had no significant effect on the biofilm characteristics. Coagulase-positive staphylococci obtained from cats did not form dense biofilms. 42.9% of methicillin-resistant Staphylococcus aureus (MRSA) isolates from cows with mastitis had moderate to strong biofilm forming properties. Isolates that showed resistance to three or more antibiotic groups tended to form denser biofilms. In addition, 73.3% of the studied S. pseudintermedius strains were found to contain the icaA gene, and 90% – the icaD gene. A genotypic profile combining both icaA and icaD genes was present in 66.7% of the bacteria, while one strain lacked both genes. Understanding the biofilm forming properties of staphylococcal isolates is important in the context of developing optimal treatment strategies and effective antibiotic use, which will contribute to better control of infections caused by these microorganisms.

Approximately 80 % of persistent wound infections are affected by the presence of bacterial biofilms, resulting in a severe clinical challenge associated with prolonged healing periods, increased morbidity, and high healthcare costs. Unfortunately, in vitro models for wound infection research almost exclusively focus on early infection stages with planktonic bacteria. In this study, we present a new approach to emulate biofilm-infected human wounds by three-dimensional human in vitro systems. For this purpose, a matured biofilm consisting of the clinical key wound pathogen Pseudomonas aeruginosa was pre-cultivated on electrospun scaffolds allowing for non-destructive transfer of the matured biofilm to human in vitro wound models. We infected tissue-engineered human in vitro skin models as well as ex vivo human skin explants with the biofilm and analyzed structural tissue characteristics, biofilm growth behavior, and biofilm-tissue interactions. The structural development of biofilms in close proximity to the tissue, resulting in high bacterial burden and in vivo-like morphology, confirmed a manifest wound infection on all tested wound models, validating their applicability for general investigations of biofilm growth and structure. The extent of bacterial colonization of the wound bed, as well as the subsequent changes in molecular composition of skin tissue, were inherently linked to the characteristics of the underlying wound models including their viability and origin. Notably, the immune response observed in viable ex vivo and in vitro models was consistent with previous in vivo reports. While ex vivo models offered greater complexity and closer similarity to the in vivo conditions, in vitro models consistently demonstrated higher reproducibility. As a consequence, when focusing on direct biofilm-skin interactions, the viability of the wound models as well as their advantages and limitations should be aligned to the particular research question of future studies. Altogether, the novel model allows for a systematic investigation of host-pathogen interactions of bacterial biofilms and human wound tissue, also paving the way for development and predictive testing of novel therapeutics to combat biofilm-infected wounds.

Biofilms are a bacterial community attached to inert or living surfaces, enveloped within a matrix of extracellular polymeric substances. This protection allows the growth and survival of bacteria in hostile environments and provides greater resistance and tolerance to antimicrobials and sanitizers. Given their propensity to form on diverse of surfaces, biofilms have significant impacts across multiple sectors, including healthcare and the industrial domains. Aiming at the development of strategies for the control and removal of bacterial biofilms, this work evaluated the impact of nineteen 2-arylidene indan-1,3-diones on both biofilm formation and preformed biofilms across various bacterial strains. The compounds exhibited a minimum inhibitory concentration (MIC) higher than 160 µg/mL, with antibiofilm assays performed at a concentration of 100 µg/mL. Among the compounds tested, the most effective in inhibiting biofilm formation were Ap18 (2-(3,4-dimethoxybenzylidene)-1H-indene-1,3(2H)-dione) against S. aureus (66.2%), Ap28 (2-(3-hydroxybenzylidene)-1H-indene-1,3(2H)-dione) against S. epidermidis (82.2%), Ap3 (2-(4-nitrobenzylidene)-1H-indene-1,3(2H)-dione) against E. coli (54.3%), and Ap25 (2-(3-hydroxy-4-methoxybenzylidene)-1H-indene-1,3(2H)-dione) against P. aeruginosa (70.8%). After 6 h, Ap18 disrupted the preformed biofilm of E. coli by 53.5% but had weak activity on the preformed biofilms of the other bacteria. The viability of VERO cells when incubated with the compounds Ap8, Ap25, and Ap27 (2-(2-hydroxybenzylidene)-1H-indene-1,3(2H)-dione) was respectively 81.8%, 67.9% and 88.0%, showing their low toxicity. This is the first work that demonstrated the antibiofilm activity of 2-arylidene indan-1,3-diones. The results can be explored to support the synthesis of more effective and less cytotoxic compounds.

In the last decade, Ficin, a proteolytic enzyme extracted from the latex sap of the wild fig tree, has been widely investigated as a promising tool for the treatment of microbial biofilms, wound healing, and oral care. Here we report the antibiofilm properties of the enzyme immobilized on soluble carboxymethyl chitosan (CMCh) and CMCh itself. Ficin was immobilized on CMCh with molecular weights of either 200, 350 or 600 kDa. Among them, the carrier with a molecular weight of 200 kDa bound the maximum amount of enzyme, binding up to 49% of the total protein compared to 19–32% of the total protein bound to other CMChs. Treatment with pure CMCh led to the destruction of biofilms formed by Streptococcus salivarius, Streptococcus gordonii, Streptococcus mutans, and Candida albicans, while no apparent effect on Staphylococcus aureus was observed. A soluble Ficin was less efficient in the destruction of the biofilms formed by Streptococcus sobrinus and S. gordonii. By contrast, treatment with CMCh200-immobilized Ficin led to a significant reduction of the biofilms of the primary colonizers S. gordonii and S. mutans. In model biofilms obtained by the inoculation of swabs from teeth of healthy volunteers, the destruction of the biofilm by both soluble and immobilized Ficin was observed, although the degree of the destruction varied between artificial plaque samples. Nevertheless, combined treatment of oral Streptococci biofilm by enzyme and chlorhexidine for 3 h led to a significant decrease in the viability of biofilm-embedded cells, compared to solely chlorhexidine application. This suggests that the use of either soluble or immobilized Ficin would allow decreasing the amount and/or concentration of the antiseptics required for oral care or improving the efficiency of oral cavity sanitization. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Controllable and on‐demand delivery of supramolecular systems have received considerable attention in modern agricultural management, especially for managing intractable plant diseases. Here, an intelligent photoresponsive pesticide delivery system is reported based on β‐cyclodextrin (β‐CD) and azobenzene, which overcomes the resistance of phytopathogens caused by the irrational use of conventional pesticides. Antibacterial bioassays illustrated that designed azobenzene derivative 3a possesses the most efficient bioactivity with EC50 values of 0.52–25.31 µg mL−1 toward three typical phytopathogens. Moreover, the assembly of the supramolecular binary complex 3a@β‐CD is successfully elucidated and displays exceptional inhibitory activity on biofilm formation. Of note, this supramolecular binary complex significantly improves the water solubility, foliar surface wettability, and shows marked light‐responsive properties. In vivo anti‐Xoo assays reveal that 3a@β‐CD has excellent control efficiency (protective activity: 51.22%, curative activity: 48.37%) against rice bacterial blight pathogens, and their control efficiency can be elevated to values of 55.84% (protective activity) and 52.05% (curative activity) by UV–vis exposure. In addition, the 3a@β‐CD are non‐toxic toward various non‐target organisms. This study therefore offers new insights into the potential of host‐guest complexes as a feasible pesticide discovery strategy characterized by a safe, biocompatible, light‐responsive release, and antibiofilm properties for overcoming intractable plant bacterial diseases. [ABSTRACT FROM AUTHOR]

Implant‐related infections (IRIs), characterized by the formation of bacterial biofilms and immunosuppressive microenvironment, are a common but tricky clinical issue. In this study, a self‐adaptive theranostics nanosystem is designed based on phase change material (PCM) for IRIs therapy, which can monitor the severity of infection in real time and automatically provide the most appropriate treatment on demand. The nanosystem called CaAlg/LOD/POD@MNO/FAs (CLPM) is made of the fatty acids (FAs) core with dissolved minocycline (MNO) and the calcium alginate (CaAlg) shell with an immobilized lactate oxidase/pyruvate oxidase (LOD/POD) enzyme‐linked system. When the level of infection is mild (wound temperature < 39 °C), the CLPMs perform a bacteriostatic function by slowly releasing MNO from the solid‐phase FAs core. When the infection deteriorates (wound temperature > 39 °C), the solid‐to‐liquid phase change of FAs not only enables a rapid release of MNO but also disrupts the mechanical strength of the biofilm skeleton doped with CLPM, performing a bactericidal function. In addition, CLPM can reduce the accumulation of bacteria‐derived lactate to address lactate‐induced immunosuppression and enhance immune memory response, thereby inhibiting infection recurrence. [ABSTRACT FROM AUTHOR]

Bacterial biofilms are widespread in the environment, and bacteria in the biofilm are highly resistant to antibiotics and possess host immune defense mechanisms, which can lead to serious clinical and environmental health problems. The increasing problem of bacterial resistance caused by the irrational use of traditional antimicrobial drugs has prompted the search for better and novel antimicrobial substances. In this paper, we review the effects of phage endolysins, modified phage endolysins, and their combination with other substances on bacterial biofilms and provide an outlook on their practical applications. Phage endolysins can specifically and efficiently hydrolyze the cell walls of bacteria, causing bacterial lysis and death. Phage endolysins have shown superior bactericidal effects in vitro and in vivo, and no direct toxicity in humans has been reported to date. The properties of phage endolysins make them promising for the prevention and treatment of bacterial infections. Meanwhile, endolysins have been genetically engineered to exert a stronger scavenging effect on biological membranes when used in combination with antibiotics and drugs. Phage endolysins are powerful weapons for controlling bacterial biofilms. [ABSTRACT FROM AUTHOR]

Staphylococcal biofilms are an important virulence factor that allows for effective infectious effects and colonization of the animal body. This study was devoted to the evaluation of the biofilm forming ability of different strains of Staphylococcus pseudintermedius and Staphylococcus aureusisolated from animals in Ukraine. In addition, the presence of extracellular adhesin genes icaA and icaD in S. pseudintermedius strains was determined. The density of the biofilms was determined by culturing microorganisms in 96-well plates and staining the resulting structures with crystal violet. The genes responsible for biofilm formation were identified by classical polymerase chain reaction (PCR) using primers selected from the literature. The data obtained from this study showed a direct correlation between the density of the biofilm and the number of viable cells involved in its formation. Thus, 23.1% of S. pseudintermedius strains and 25% of S. aureus strains isolated from dogs demonstrated the ability to form a dense biofilm, while 46.2% of S. pseudintermedius strains and 50% of S. aureus strains formed a weak biofilm. The origin of the isolates had no significant effect on the biofilm characteristics. Coagulase-positive staphylococci obtained from cats did not form dense biofilms. 42.9% of methicillin-resistant Staphylococcus aureus(MRSA) isolates from cows with mastitis had moderate to strong biofilm forming properties. Isolates that showed resistance to three or more antibiotic groups tended to form denser biofilms. In addition, 73.3% of the studied S. pseudintermedius strains were found to contain the icaA gene, and 90% – the icaD gene. A genotypic profile combining both icaA and icaD genes was present in 66.7% of the bacteria, while one strain lacked both genes. Understanding the biofilm forming properties of staphylococcal isolates is important in the context of developing optimal treatment strategies and effective antibiotic use, which will contribute to better control of infections caused by these microorganisms. [ABSTRACT FROM AUTHOR]

Antimicrobial peptides have gradually attracted interest as promising alternatives to conventional agents to control the worldwide health threats posed by antibiotic resistance and cancer. Crabrolin is a tridecapeptide extracted from the venom of the European hornet (Vespa crabro). Its antibacterial and anticancer potentials have been underrated compared to other peptides discovered from natural resources. Herein, a series of analogs were designed based on the template sequence of crabrolin to study its structure–activity relationship and enhance the drug's potential by changing the number, type, and distribution of charged residues. The cationicity-enhanced derivatives were shown to have improved antibacterial and anticancer activities with a lower toxicity. Notably, the double-arginine-modified product, crabrolin-TR, possessed a potent capacity against Pseudomonas aeruginosa (minimum inhibitory concentration (MIC) = 4 μM), which was around thirty times stronger than the parent peptide (MIC = 128 μM). Furthermore, crabrolin-TR showed an in vivo treatment efficacy in a Klebsiella-pneumoniae-infected waxworm model and was non-toxic under its maximum MBC value (MIC = 8 μM), indicating its therapeutic potency and better selectivity. Overall, we rationally designed functional peptides by progressively increasing the number and distribution of charged residues, demonstrating new insights for developing therapeutic molecules from natural resources with enhanced properties, and proposed crabrolin-TR as an appealing antibacterial and anticancer agent candidate for development. [ABSTRACT FROM AUTHOR]

[Display omitted] The biofilms formed by bacteria at the wound site can effectively protect the bacteria, which greatly weakens the effect of antibiotics. Herein, a microneedle patch for wound treatment is designed, which can effectively penetrate the biofilms in a physical way because of the penetration ability of the microneedles and the motion behavior of the nanomotors, and deliver bacterial quorum sensing inhibitor luteolin (Le) and nanomotors with multiple antibacterial properties within biofilms. Firstly, the nanomotors-loaded microneedle patches are prepared and characterized. The results of in vitro and in vivo experiments show that the microneedle patches have good biosafety and antibacterial properties. Among them, Le can inhibit the growth of biofilms. Further, under near-infrared (NIR) irradiation, the nanomotors loaded with photosensitizer ICG and nitric oxide (NO) donor L -arginine (L-Arg) can move in the biofilms under the double driving effect of photothermal and NO, and can give full play to the multiple anti-biological infection effects of photothermal therapy (PTT), photodynamic therapy (PDT) and NO, and finally realize the effective removal of biofilms and promote wound healing. The intervention of nanomotor technology has brought about a new therapeutic strategy for bacterial biofilm-related infection of wound. [ABSTRACT FROM AUTHOR]

Urinary tract infections (UTIs) are the second most common bacterial infection with high recurrence rates and can involve biofilm formation on patient catheters. Biofilms are inherently tolerant to antimicrobials, making them difficult to eradicate. Many antibiofilm agents alone do not have bactericidal activity; therefore, linking them to antibiotics is a promising antibiofilm strategy. However, many of these hybrid agents have not been tested in relevant preclinical settings, limiting their potential for clinical translation. Here, we evaluate a ciprofloxacin di-nitroxide hybrid (CDN11), previously reported to have antibiofilm activity against uropathogenic Escherichia coli (UPEC) strain UTI89 in vitro, as a potential UTI therapeutic using multiple preclinical models that reflect various aspects of UTI pathogenesis. We report improved in vitro activity over the parent drug ciprofloxacin against mature UTI89 biofilms formed inside polyethylene catheters. In bladder cell monolayers infected with UTI89, treatment with CDN11 afforded significant reduction in bacterial titers, including intracellular UPEC. Infected mouse bladders containing biofilm-like intracellular reservoirs of UPEC UTI89 showed decreased bacterial loads after ex vivo bladder treatment with CDN11. Activity for CDN11 was reported across different models of UTI, showcasing nitroxide–antibiotic hybridization as a promising antibiofilm approach. The pipeline we described here could be readily used in testing other new therapeutic compounds, fast-tracking the development of novel antibiofilm therapeutics. [ABSTRACT FROM AUTHOR]

Various serovars of Salmonella had been the subject of research for over 150 years; nonetheless, the bacterium has remained an important pathogen of public health concern to date. The tremendous ability of Salmonella to form biofilms on biotic and abiotic surfaces is an important underlying reason for the prevalence of this opportunistic pathogen in healthcare, manufacturing, and the food chain. The current study illustrates that using very common industrial antimicrobial treatments at the highest concentrations suggested by the manufacturers is only efficacious against planktonic and one-day mature biofilms of the pathogen while exhibiting a lack of efficacy for complete removal of bacterial biofilms formed for longer than 2 days. This exhibits the importance of preventive measures against Salmonella biofilm formation in healthcare and manufacturing facilities, schools, nursing homes, and domestic environments. Additionally, our study illustrates the importance of including both planktonic and sessile cells of the pathogen in microbiology validation studies, especially for niche and hard-to-reach surfaces. The current study additionally investigated the suitability of an avirulent strain of the pathogen as a surrogate for pathogenic Salmonella serovars for public health microbiology validation studies when the use of virulent strains is not economically feasible or not possible due to safety concerns.

Small-scale gold mining is one of the sectors that contribute to the world's largest mercury contamination through the tailings it produces. Many efforts have been made to reduce mercury concentrations from tailings, one of which is by utilizing a combination of plants and bacteria. This study aims to analyze the combination of mercury-resistant biofilm-forming bacteria and local plants in the phytoremediation of small-scale gold mine tailings. This study used ten plant species divided into three groups and three biofilm-forming mercury-resistant bacteria (Bacillus toyonensis, Burkholderia cepacia, and Microbacterium chocolatum). Parameters observed included plant biomass, total chlorophyll, plant mercury content and media. The results showed that adding bacteria to each plant in the treatment had a different effect. Some plants with the addition of biofilm-forming bacteria had a higher wet weight than others. However, the addition of bacteria was not effective in increasing plant dry weight. The combination of biofilm-forming bacteria in the first and second plant groups reduced tailings mercury concentrations better than without the addition of bacteria. The combination of plants and bacteria in the third group gave higher media and plant mercury concentrations. This study shows that the addition of biofilm-forming bacteria can lead to increased remediation by plants. The second plant group treatment with a combination of P. indica, P. conjugatum, and S. sesban plants was the most effective in reducing tailings mercury content.