Biotic Surfaces Research Articles

Comparative Adhesion of Pseudomonas aeruginosa to Human Oral Mucosal Epithelial Cells and Polystyrene Surfaces

Background: The adhesion of bacteria to biotic and abiotic surfaces reflects their ability to cause infectious diseases. The distinction between the ability of Pseudomonas aeruginosa bacteria to adhere to biotic and abiotic surfaces is not clear in the literature. Objectives: The current study aims to shed light on the extent of similarities and differences between P. aeruginosa in terms of their ability to adhere to different biotic and abiotic surfaces. Materials and Methods: ten isolates of P. aeruginosa were isolated from 100 wound and burn swabs. The isolates were identified using biochemical and phenotypic tests in addition to VITIK-II technology. The susceptibility to antibiotics was estimated using the disc diffusion method. The microtiter-spectrophotometric was used to measure the biofilm formation on polystyrene microtiter plates. The Human oral mucosal epithelial (OMECs) were used to evaluate the adhesion of P. aeruginosa isolates. Plate count and direct bacterial count were used to count the adhered bacteria to human OMECs in vitro. Results: Norfloxacin showed the highest antibacterial effect while the lowest antibacterial effect was seen in the case of using when Amoxicillin and Cefixime (all isolates were resistant). All isolates from, Pa2 form the highest biofilm followed by Pa6, while the lowest biofilm formation was seen in the case of Pa4. While Pa 6 showed the highest ability to attach to human OMECs followed by Pa2. Conclusion: It can be concluded that P. aeruginosa isolates are resistant to most antibiotics and that their ability to adhere and biofilm formation depends on the type of surface.

A perspective on nanomaterials against Campylobacter jejuni biofilm - new control strategies.

Campylobacter jejuni - a Gram-negative bacterium - is considered the fourth cause of diarrheic diseases that can form biofilms (mono and multi-species) or colonize pre-existing biofilms adhering to both, inert or biotic surfaces; its biofilms contribute to transmission through the food chain and survival under harsh environmental conditions. Thus, developing alternatives against this pathogen is compulsory. Nanomaterials have revolutionized the way of fighting infections related to biofilms due to their unique properties compared to traditional antibiotics. Nanomaterials have also been used against C. jejuni based on zinc, titanium, silver, molybdenum, magnesium, cobalt, erbium, lithium, nickel, hydroxide, polyethylene, graphene, lipids, chitosan, and poly(lactic-co-glycolic acid) (PLGA). Those organic and inorganic materials have synthesized nanoparticles, nanofillers, nanowires, nanoferrites, double layers, nanocomposites, and films that have encapsulated, entrapped, coated or doped molecules. Additionally, bare metal nanoparticles have been tested by their antimicrobial activity on planktonic and sessile forms. Therefore, the present review aimed to describe general biology virulence factors, host-pathogen relationships and biofilm formation, as well as nanomaterials and nanoparticles fighting against C. jejuni biofilms. Considerations are presented and placed in perspective.

Reactive oxygen species-inducing itraconazole and its anti-biofilm activity against resistant Candida parapsilosis sensu lato biofilm cells isolated from patients with recalcitrant onychomycosis.

Candida parapsilosis was introduced as the second most responsible for nail involvement. The colonization of biotic and abiotic surfaces by Candida spp.can result in the formation of biofilms, which possess a high level of resistance to typical antifungal agents. Since Candida spp. can produce biofilm mass on the surface of the nails, dermatologists should consider appropriate antifungals to eliminate both the planktonic and biofilm cells. The aim of this research was to determine the antifungal efficacy of itraconazole against C. parapsilosis sensu lato biofilm formations, in addition to its static effects. Ten C. parapsilosis sensu lato isolates were enrolled in this study. The use of itraconazole results in the accumulation of reactive oxygen species (ROS) during treatment. In order to verify the correlation between ROS and itraconazole-induced cell death, the viability of cells was analyzed by administering the ROS scavenger Ascorbic acid. The apoptotic features of itraconazole were analyzed using the Annexin V-FITC method. Based on current data, it was found that the generation of intracellular stresses by itraconazole is not observed in cells upon ROS inhibition, emphasizing the importance of intracellular ROS in the apoptotic mechanism of itraconazole. Targeting the oxidative defense system is a powerful point to use ROS-inducing antifungals as a superior choice for more effective therapies in case of recalcitrant onychomycosis.

Impact of nitric oxide donors on capsule, biofilm and resistance profiles of Klebsiella pneumoniae

Klebsiella pneumoniae is considered to be a critical public health threat due to its ability to cause fatal, multi-drug-resistant infections in the bloodstream and key organs. The polysaccharide-based capsule layer that shields K. pneumoniae from clearance via innate immunity is a prominent virulence factor. K. pneumoniae also forms biofilms on biotic and abiotic surfaces. These biofilms significantly reduce penetration by, and antibacterial activity from, traditional antibiotics. Nitric oxide (NO), an endogenous molecule involved in the innate immune system, is equally effective at eradicating bacteria but without engendering resistance. This study investigated the effects of NO-releasing small molecules capable of diverse release kinetics on the capsule and biofilm formation characteristics of multiple K. pneumoniae strains. The use of NO donors with moderate and extended NO-release properties (i.e., half-life >1.8 h) inhibited bacterial growth. Additionally, treatment with NO decreased capsule mucoviscosity in K. pneumoniae strains that normally exhibit hypermucoviscosity. The NO donors were also effective against K. pneumoniae biofilms at the same minimum biocidal concentrations that eliminated planktonic bacteria, while meropenem showed little antibacterial action in the same experiments. These results represent the first account of exogenous NO affecting biomarkers involved in K. pneumoniae infections, and may therefore inform future development of NO-based therapeutics for treating such infections.

Predicting 3D and 2D surface area of corals from simple field measurements

The structural architecture of coral reefs is a known predictor of species richness, fish biomass and reef resilience. At a smaller scale, three-dimensional (3D) surface area of corals is a fundamental determinant of physical and biological processes. Quantifying the 3D surface area of corals has applications for a broad range of scientific disciplines, including carbonate production estimates, coral predation studies, and assessments of reef growth. Here, we present morphotaxon-specific conversion metrics to estimate total 3D surface area and projected 2D surface area of individual colonies from simple field measurements of colony maximum diameter. Underwater photogrammetry techniques were used to quantify surface area and estimate conversion metrics. Bayesian models showed strong non-linear (power) relationships between colony maximum diameter and both total 3D surface area and projected 2D surface area for 13 out of 15 morphotaxa. This study presents a highly resolved and efficient method for obtaining critical surface area assessments of corals for various applications, including assessments of biotic surface area, tissue biomass, calcification rates, coral demographic rates, and reef restoration monitoring.

Assessment of mrkD and T1 fim Genes of K. pneumoniae and Their Association with Biofilm Formation in Community-Acquired Infections

Background: Klebsiella pneumoniae is a pathogenic bacteria that can form biofilms on abiotic and biotic surfaces. The constraints of the therapeutic choices against K. pneumoniae arise from its innate capacity to develop biofilm and harboring determinants of multidrug resistance. Objective: The current study aimed to assess the prevalence of some fimbrial genes (type 1 and type 3) of K. pneumoniae strains in community-acquired infections obtained from various clinical sources on their ability to produce biofilm. Methods: A total of 256 samples (106 male and 150 females) were taken from various clinical sources including Urine, wound swabs, sputum, burn swabs, bronchial wash, diabetic foot ulcer, and higher vaginal swabs) from outpatients in Kirkuk City hospitals. The isolates were identified on the Blood agar, MacConkey agar and Eosin Methylene Blue agar based on the cultural, morphological, in addition to biochemical assays, and confirmed using the automated VITEK 2 system. The Microtiter plate (MTP) method was employed to detect Biofilm formation. Subsequently, a polymerase chain reaction was performed to determine the presence of the T1 fim and mrkD genes. Result: Out of 256 only 38 (14.8%) isolates belonged to Klebsiella pneumoniae. Of all isolates, 38(100%) were biofilm producers. The PCR results revealed that all 38 isolates showed positive (100%) for T1 fim and 37 isolates (97.4%) for mrkD.

Artificial Intelligence-Driven Analysis of Antimicrobial-Resistant and Biofilm-Forming Pathogens on Biotic and Abiotic Surfaces.

The growing threat of antimicrobial-resistant (AMR) pathogens to human health worldwide emphasizes the need for more effective infection control strategies. Bacterial and fungal biofilms pose a major challenge in treating AMR pathogen infections. Biofilms are formed by pathogenic microbes encased in extracellular polymeric substances to confer protection from antimicrobials and the host immune system. Biofilms also promote the growth of antibiotic-resistant mutants and latent persister cells and thus complicate therapeutic approaches. Biofilms are ubiquitous and cause serious health risks due to their ability to colonize various surfaces, including human tissues, medical devices, and food-processing equipment. Detection and characterization of biofilms are crucial for prompt intervention and infection control. To this end, traditional approaches are often effective, yet they fail to identify the microbial species inside biofilms. Recent advances in artificial intelligence (AI) have provided new avenues to improve biofilm identification. Machine-learning algorithms and image-processing techniques have shown promise for the accurate and efficient detection of biofilm-forming microorganisms on biotic and abiotic surfaces. These advancements have the potential to transform biofilm research and clinical practice by allowing faster diagnosis and more tailored therapy. This comprehensive review focuses on the application of AI techniques for the identification of biofilm-forming pathogens in various industries, including healthcare, food safety, and agriculture. The review discusses the existing approaches, challenges, and potential applications of AI in biofilm research, with a particular focus on the role of AI in improving diagnostic capacities and guiding preventative actions. The synthesis of the current knowledge and future directions, as described in this review, will guide future research and development efforts in combating biofilm-associated infections.

Antibiofilm effect of biogenic silver nanoparticle alone and combined with polymyxin B against carbapenem-resistant Acinetobacter baumannii.

Acinetobacter baumannii is a bacteria associated with nosocomial infections and outbreaks, difficult to control due to its antibiotic resistance, ability to survive in adverse conditions, and biofilm formation adhering to biotic and abiotic surfaces. Therefore, this study aimed to evaluate the antibiofilm activity of biogenic silver nanoparticle (Bio-AgNP) and polymyxin B alone and combined in biofilms formed by isolates of carbapenem-resistant A. baumannii (CR-Ab). In the biofilm formation inhibition assay, CR-Ab strains were exposed to different concentrations of the treatments before inducing biofilm formation, to determine the ability to inhibit/prevent bacterial biofilm formation. While in the biofilm rupture assay, the bacterial biofilm formation step was previously carried out and the adhered cells were exposed to different concentrations of the treatments to evaluate their ability to destroy the bacterial biofilm formed. All CR-Ab isolates and ATCC® 19606™ used in this study are strong biofilm formers. The antibiofilm activity of Bio-AgNP and polymyxin B against CR-Ab and ATCC® 19606™ demonstrated inhibitory and biofilm-disrupting activity. When used in combination, Bio-AgNP and polymyxin B inhibited 4.9-100% of biofilm formation in the CR-Ab isolates and ATCC® 19606™. Meanwhile, when Bio-AgNP and polymyxin B were combined, disruption of 6.8-77.8% of biofilm formed was observed. Thus, antibiofilm activity against CR-Ab was demonstrated when Bio-AgNP was used alone or in combination with polymyxin B, emerging as an alternative in the control of CR-Ab strains.

Luteolin exhibits antimicrobial actions against Salmonella Typhimurium and Escherichia coli: Impairment of cell adhesion, membrane integrity, and energy metabolism

There has been an increasing interest in phytochemicals with antimicrobial properties in food safety management. However, the mechanisms of action of phytochemicals remain mostly unknown, preventing their selective applications against biofilms of specific pathogenic bacteria. The objectives of the present study were to understand the antibiofilm and antibacterial properties of luteolin (LUT) and its modes of action against two detrimental foodborne pathogens, Salmonella enterica ser. Typhimurium and enterohemorrhagic Escherichia coli. The focus encompasses biofilm inhibition, interference with cell adhesion, disruption of membrane integrity, and dysfunctions of membrane-linked bacterial electron transport systems and energy metabolism. Our findings evidence that LUT prevents pathogenic biofilm formation on both biotic (eggshell) and abiotic (stainless steel and silicon rubber) surfaces by resisting irreversible cell adhesion and interfering with hydrophobic interactions between bacteria and contact surfaces. Our comprehensive biochemical and visual analyses further reveal that LUT mainly exhibits bactericidal activities by imposing oxidative stress on cells, leading to severe cellular structure damage, inhibition of metabolic and respiratory activities, and dysfunctions of energy metabolism, ultimately resulting in bacterial cell death. This study suggests that LUT has the potential to serve as a solution for developing effective, novel antimicrobials for improving food safety management.

Enhanced Cr(VI) removal and stabilization from bioleached wastewater by zero-valent iron coupled with hetero and autotrophic bacteria

Zero-valent iron (Fe0) usually suffers from organic acid complexation and ferrochrome layer passivation in Cr(VI) removal from bioleached wastewater of Cr slag. In this work, a synergetic system combined Fe0 and mixed hetero/autotrophic bacteria was established to reduce and stabilize Cr(VI) from bioleached wastewater. Due to bacterial consumption of organic acid and hydrogen, severe iron corrosion and structured-Fe(II) mineral generation (e.g., magnetite and green rust) occurred on biotic Fe0 surface in terms of solid-phase characterization, which was crucial for Cr(VI) adsorption and reduction. Therefore, compared with the abiotic Fe0 system, this integrated system exhibited a 6.1-fold increase in Cr(VI) removal, with heterotrophic reduction contributing 3.4-fold and abiotic part promoted by hydrogen-autotrophic bacteria enhancing 2.7-fold. After reaction, the Cr valence distribution and X-ray photoelectron spectroscopy indicated that most Cr(VI) was converted into immobilized products such as FexCr1-x(OH)3, Cr2O3, and FeCr2O4 by biotic Fe0. Reoxidation experiment revealed that these products exhibited superior stability to the immobilized products generated by Fe0 or bacteria. Additionally, organic acid concentration and Fe0 dosage showed significantly positive correlation with Cr(VI) removal within the range of biological adaptation, which emphasized that heterotrophic and autotrophic bacteria acted essential roles in Cr(VI) removal. This work highlighted the enhanced effect of heterotrophic and autotrophic activities on Cr(VI) reduction and stabilization by Fe0 and offered a promising approach for bioleached wastewater treatment.

Biofilm-producing ability of methicillin-resistant Staphylococcus aureus clinically isolated in China

BackgroundStaphylococcus aureus, a commensal bacterium, colonizes the skin and mucous membranes of approximately 30% of the human population. Apart from conventional resistance mechanisms, one of the pathogenic features of S. aureus is its ability to survive in a biofilm state on both biotic and abiotic surfaces. Due to this characteristic, S. aureus is a major cause of human infections, with Methicillin-Resistant Staphylococcus aureus (MRSA) being a significant contributor to both community-acquired and hospital-acquired infections.ResultsAnalyzing non-repetitive clinical isolates of MRSA collected from seven provinces and cities in China between 2014 and 2020, it was observed that 53.2% of the MRSA isolates exhibited varying degrees of ability to produce biofilm. The biofilm positivity rate was notably high in MRSA isolates from Guangdong, Jiangxi, and Hubei. The predominant MRSA strains collected in this study were of sequence types ST59, ST5, and ST239, with the biofilm-producing capability mainly distributed among moderate and weak biofilm producers within these ST types. Notably, certain sequence types, such as ST88, exhibited a high prevalence of strong biofilm-producing strains. The study found that SCCmec IV was the predominant type among biofilm-positive MRSA, followed by SCCmec II. Comparing strains with weak and strong biofilm production capabilities, the positive rates of the sdrD and sdrE were higher in strong biofilm producers. The genetic determinants ebp, icaA, icaB, icaC, icaD, icaR, and sdrE were associated with strong biofilm production in MRSA. Additionally, biofilm-negative MRSA isolates showed higher sensitivity rates to cefalotin (94.8%), daptomycin (94.5%), mupirocin (86.5%), teicoplanin (94.5%), fusidic acid (81.0%), and dalbavancin (94.5%) compared to biofilm-positive MRSA isolates. The biofilm positivity rate was consistently above 50% in all collected specimen types.ConclusionsMRSA strains with biofilm production capability warrant increased vigilance.

Simulation and Modeling of the Adhesion of Staphylococcus aureus onto Inert Surfaces under Fluid Shear Stress.

Bacterial adhesion to biotic and abiotic surfaces under fluid shear stress plays a major role in the pathogenesis of infections linked to medical implants and tissues. This study employed an automated BioFlux 200 microfluidic system and video microscopy to conduct real-time adhesion assays, examining the influence of shear stress on adhesion kinetics and spatial distribution of Staphylococcus aureus on glass surfaces. The adhesion rate exhibited a non-linear relationship with shear stress, with notable variations at intermediate levels. Empirical adhesion events were simulated with COMSOL Multiphysics® and Python. Overall, COMSOL accurately predicted the experimental trend of higher rates of bacterial adhesion with decreasing shear stress but poorly characterized the plateauing phenomena observed over time. Python provided a robust mathematical representation of the non-linear relationship between cell concentration, shear stress, and time but its polynomial regression approach was not grounded on theoretical physical concepts. These insights, combined with advancements in AI and machine learning, underscore the potential for synergistic computational techniques to enhance our understanding of bacterial adhesion to surfaces, offering a promising avenue for developing novel therapeutic strategies.

Effect of electroinductive conditions on biofilm production capacity of some industrially important bacteria

Biofilms are intricate microbial deposits on biotic and abiotic surfaces, with significant medical and biotechnological implications. This study explored biofilm formation by Acetobacter aceti ATCC15973, Pseudomonas aeruginosa ATCC9027, Serratia marcescens ATCC14756, Gluconobacter oxydans ATCC19357, Rhodobacter sphaeroides ATCC17023, and Bacillus subtilis ATCC6633 on wood, glass, steel, PVC, and PET surfaces using qualitative methods. Effects of electrical stimulation (6V, 4.5A), magnetic fields (1000 G), and electromagnetic flux (5 mT) on biofilm formation were assessed via Crystal Violet Binding Assay. G. oxydans ATCC19357 exhibited highest adherence on PVC and wood (2.0145 and 2.402 log cfu/ml, respectively) under electrical stimulation. A. aceti ATCC15973 showed highest adherence on steel, PET, and glass (1.944, 0.9005, and 0.876 log cfu/ml). R. sphaeroides ATCC17023 demonstrated highest adherence on PVC, steel, PET, and glass (1.0895 to 1.7495 log cfu/ml) under magnetic induction; B. subtilis ATCC6633 had highest wood adherence (1.491 log cfu/ml). G. oxydans ATCC19357 showed highest overall adhesion with electromagnetic induction. PVC supported highest biofilm growth (39 %). Biophysical factors varied in enhancing biofilm formation, suggesting potential for bacterial immobilization technologies in bioremediation and industrial fermentation

Phenotypic Investigation and Detection of Biofilm-Associated Genes in Acinetobacter baumannii Isolates, Obtained from Companion Animals.

Bacteria of the genus Acinetobacter, especially Acinetobacter baumannii (Ab), have emerged as pathogens of companion animals during the last two decades and are commonly associated with hospitalization and multidrug resistance. A critical factor for the distribution of relevant strains in healthcare facilities, including veterinary facilities, is their adherence to both biotic and abiotic surfaces and the production of biofilms. A group of 41 A. baumannii isolates obtained from canine and feline clinical samples in Greece was subjected to phenotypic investigation of their ability to produce biofilms using the tissue culture plate (TCP) method. All of them (100%) produced biofilms, while 23 isolates (56.1%) were classified as strong producers, 11 (26.8%) as moderate producers, and 7 (17.1%) as weak producers. A correlation between the MDR and XDR phenotypes and weak or moderate biofilm production was identified. Moreover, the presence of four biofilm-associated genes bap, blaPER, ompA, and csuE was examined by PCR, and they were detected in 100%, 65.9%, 97.6%, and 95.1% of the strains respectively. All isolates carried at least two of the investigated genes, whereas most of the strong biofilm producers carried all four genes. In conclusion, the spread and persistence of biofilm-producing Ab strains in veterinary facilities is a matter of concern, since they are regularly obtained from infected animals, indicating their potential as challenging pathogens for veterinarians due to multidrug resistance and tolerance in conventional eradication measures. Furthermore, considering that companion animals can act as reservoirs of relevant strains, public health concerns emerge.

In silico genome wide identification of long non-coding RNAs differentially expressed during Candida auris host pathogenesis.

Candida auris is an invasive fungal pathogen of high concern due to acquired drug tolerance against antifungals used in clinics. The prolonged persistence on biotic and abiotic surfaces can result in onset of hospital outbreaks causing serious health threat. An in depth understanding of pathology of C. auris is highly desirable for development of efficient therapeutics. Non-coding RNAs play crucial role in fungal pathology. However, the information about ncRNAs is scanty to be utilized. Herein our aim is to identify long noncoding RNAs with potent role in pathobiology of C. auris. Thereby, we analyzed the transcriptomics data of C. auris infection in blood for identification of potential lncRNAs with regulatory role in determining invasion, survival or drug tolerance under infection conditions. Interestingly, we found 275 lncRNAs, out of which 253 matched with lncRNAs reported in Candidamine, corroborating for our accurate data analysis pipeline. Nevertheless, we obtained 23 novel lncRNAs not reported earlier. Three lncRNAs were found to be under expressed throughout the course of infection, in the transcriptomics data. 16 of potent lncRNAs were found to be coexpressed with coding genes, emphasizing for their functional role. Noteworthy, these ncRNAs are expressed from intergenic regions of the genes associated with transporters, metabolism, cell wall biogenesis. This study recommends for possible association between lncRNA expression and C. auris pathogenesis.

Antibodies anti-rFilF protein has anti-biofilm activity against carbapenem-resistant Acinetobacter baumannii

Acinetobacter baumannii is an opportunistic bacterium that causes infection in several sites. Carbapenem-resistant A. baumannii strains (CRAb) lead the World Health Organization's list of 12 pathogens considered a priority for developing new antimicrobials. The pathogenicity of A. baumannii is related to the different virulence factors employed in the colonization of biotic and abiotic surfaces, biofilm formation and multidrug resistance. We analyze the outer membrane protein FilF from A. baumannii in silico and produce it in recombinant form (rFilF). rFilF protein was successfully expressed in Escherichia coli BL21 Star in an insoluble form. Immunization with rFilF induced significant anti-rFilF IgG antibody production in mice, detected by indirect enzyme-linked immunosorbent assay, since the first evaluation until 49th. On the last experimentation day, the predominant immunoglobulin found was IgG1 followed by IgG2a, IgG2b, IgM, IgG3, and IgA. We observe that interleukins 4 and 10 show significant production after the 28th day of experimentation in mice immunized with rFilF. Anti-rFilF pAbs were able to inhibit biofilm formation in nine CRAb strains evaluated, and in the standard strain ATCC® 19606. These results demonstrate the anti-biofilm activity of anti-rFilF antibodies, promising in the development of a non-antibiotic approach based on the control of CRAb strains.

Modulation of Campylobacter jejuni adhesion to biotic model surfaces by fungal lectins and protease inhibitors.

Campylobacter jejuni, a Gram-negative bacterium, is one of the most common causes of foodborne illness worldwide. Its adhesion mechanism is mediated by several bacterial factors, including flagellum, protein adhesins, lipooligosaccharides, proteases, and host factors, such as surface glycans on epithelial cells and mucins. Fungal lectins, specialized carbohydrate-binding proteins, can bind to specific glycans on host and bacterial cells and thus influence pathogenesis. In this study, we investigated the effects of fungal lectins and protease inhibitors on the adhesion of C. jejuni to model biotic surfaces (mucin, fibronectin, and collagen) and Caco-2 cells as well as the invasion of Caco-2 cells. The lectins Marasmius oreades agglutinin (MOA) and Laccaria bicolor tectonin 2 (Tec2) showed remarkable efficacy in all experiments. In addition, different pre-incubations of lectins with C. jejuni or Caco-2 cells significantly inhibited the ability of C. jejuni to adhere to and invade Caco-2 cells, but to varying degrees. Pre-incubation of Caco-2 cells with selected lectins reduced the number of invasive C. jejuni cells the most, while simultaneous incubation showed the greatest reduction in adherent C. jejuni cells. These results suggest that fungal lectins are a promising tool for the prevention and treatment of C. jejuni infections. Furthermore, this study highlights the potential of fungi as a rich reservoir for novel anti-adhesive agents.

In vitro Inhibitory effects of Polyherbal Formulation on Biofilm-forming bacteria in Chronic wounds

Biofilm is a complex microbial community highly resistant to antimicrobials. The formation of biofilms in biotic and abiotic surfaces is associated with high rates of morbidity and mortality in hospitalized patients. The aim of the present study was to develop a polyherbal formulation for antibacterial activity and inhibition of biofilm formation. Andrographis paniculata (leaves), Cassia fistula (flower), Gymnema sylvestre (leaves), Ocimum tenuiflorforum (leaves), Cinnamomum verum (bark)were the herbs chosen for the study. The extraction of the herbal samples was carried out using the cold extraction method and their phytochemical characterization was carried out by GC-MS analysis. The anti-microbial activity and antibiofilm activity of polyherbal formulation was carried out using the agar well diffusion method and microtitre plate assay. The phytochemical results showed the presence of resins, carbohydrates, proteins, saponin and phenol. The agar well diffusion assay results and microtitre plate assay showed the highest activity exhibited with 500µg/ml of polyherbal extract against Pseudomonas aeruginosa and lowest against Escherichia coli. The results confirm the differences in antibacterial and antibiofilm activity of polyherbal formulation of various concentration. Larger concentration of formulation showed to be more effective against biofilm cells. The purpose of this study was to investigate the anti-biofilm properties and inhibitory impact of ACGOC extracts against the most prevalent clinical isolates such as S. aureus,B.pumilusand P. aeruginosa and so the hypothesis of synergistic interaction of biologically active compounds from five different herbal extracts was proved for its antibiofilm assays.

Adhesion of Klebsiella oxytoca to bladder or lung epithelial cells is promoted by the presence of other opportunistic pathogens

The intestinal and respiratory tracts of healthy individuals serve as habitats for a diverse array of microorganisms, among which Klebsiella oxytoca holds significance as a causative agent in numerous community- and hospital-acquired infections, often manifesting in polymicrobial contexts. In specific circumstances, K. oxytoca, alongside other constituents of the gut microbiota, undergoes translocation to distinct physiological niches. In these new environments, it engages in close interactions with other microbial community members. As this interaction may progress to co-infection where the virulence of involved pathogens may be promoted and enhance disease severity, we investigated how K. oxytoca affects the adhesion of commonly co-isolated bacteria and vice versa during co-incubation of different biotic and abiotic surfaces. Co-incubation was beneficial for the adhesion of at least one of the two co-cultured strains. K. oxytoca enhanced the adhesion of other enterobacteria strains to polystyrene and adhered more efficiently to bladder or lung epithelial cell lines in the presence of most enterobacteria strains and S. aureus. This effect was accompanied by bacterial coaggregation mediated by carbohydrate-protein interactions occurring between bacteria. These interactions occur only in sessile, but not planktonic populations, and depend on the features of the surface. The data are of particular importance for the risk assessment of the urinary and respiratory tract infections caused by K. oxytoca, including those device-associated. In this paper, we present the first report on K. oxytoca ability to acquire increased adhesive capacities on epithelial cells through interactions with common causal agents of urinary and respiratory tract infections.

Immobilised antimicrobial peptides in downregulation of biofilm.

Colonisation of sessile bacterial species on biotic and abiotic surfaces is responsible for the development of various infections in humans. At present, biofilm-associated chronic infections have been a prime concern among the healthcare practitioners since they are impermeable to drugs, resulting in the development of antibiotic resistance or multi-drug resistance. For a few decades, a lot of research activity has been performed in the development of alternative therapeutics to combat biofilm-associated chronic infections. The presence of extracellular polymeric substance (EPS) prevents the permeation of most of the drugs rendering drug failures. The use of small molecules has been necessary to penetrate easily through the EPS and act on the targeted cells. In present days, the use of antimicrobial peptides (AMPs) has gained immense importance as alternative therapeutics since they exhibit a novel class of antibiotics exhibiting a wide spectrum of activity and possess a low rate of development of resistance. In the last few decades, a large number of AMPs have been identified from varied groups of organisms as effector molecules for innate immune system acting as an important line of defence. In this review, we will discuss the use of AMPs as effective agents to combat various biofilm-associated chronic infections.