Substrate For Biofilm Formation Research Articles

Inhibition of Candida albicans and Staphylococcus epidermidis mixed biofilm formation in a catheter disk model system treated with EtOH-EDTA solution.

Microbial colonization and the formation of biofilms on catheter surfaces pose a great risk for medical-related infections. We aimed (a) to evaluate polymicrobial biofilm formation of Candida albicans and Staphylococcus epidermidis and (b) to investigate the inhibition and effects of ethanol (EtOH) and EtOH-EDTA solutions on biofilms. Catheter disks were made and used as a substrate for biofilm formation. Varying concentrations of EtOH and EtOH-EDTA solutions were compared in deterring biofilm formation. The EtOH-EDTA solutions were further tested to remove mature and preformed biofilms. Compared to their monospecies counterparts, biofilm concentration significantly increases when C. albicans is co-cultured with S. epidermidis. Moreover, all treatments with EtOH-EDTA solution significantly lowered biofilm formation compared to EtOH alone (P≤0.05). Lastly, biofilm was dramatically reduced when treated with 20%, 30%, 40%, and 50% EtOH-EDTA solutions (P≤0.05). Our findings suggest that biofilms become more resilient to treatment when formed by multiple organisms. Nonetheless, treatment with EtOH-EDTA is effective against these polymicrobial biofilms.

Selection of antibiotic resistance genes on biodegradable and non-biodegradable microplastics

Growing evidence have demonstrated that microplastics in the marine ecosystem can provide novel substrates for biofilm formation, potentially facilitating the spread of antibiotic resistance. However, the occurrence of antibiotic resistance genes (ARGs) in the biofilm on microplastics has not been fully explored. This study used the metagenomic data of biodegradable and non-biodegradable microplastics staged at a coastal lagoon in the northern Gulf of Mexico to profile the ARGs and their bacterial hosts. The abundance and Shannon diversity of ARGs on biodegradable poly hydroxy alkanoate (PHA) and non-biodegradable polyethylene terephthalate (PET) have no significant differences. Nevertheless, the abundance of multidrug resistance genes on PET (3.05 copies per 16S rRNA) was statistically higher than that on PHA (2.05). Beta diversity showed that the overall pattern of resistome on PHA was significantly distinct with that on PET. Procrustes analysis suggested a good-fit correlation between ARG profiles and bacterial community composition. The host-tracking analysis identified that Pseudomonas was always the major host for glycopeptide and multidrug resistance genes in PET and PHA biofilms, whereas the primary host for macrolide-lincosamide-streptogramin (MLS) changed to Desulfovibrio on PET. This study provided the first metagenomic insights into the ARGs and their hosts on biodegradable and non-biodegradable microplastics, suggesting that both two types of plastics harbor ARGs with preferences.

In-vitro antibiofilm activity of selected medicinal plants against Staphylococcus aureus biofilm on chitin flakes as substrate

The aim of the study is to assess the antibiofilm activity of ethanolic extracts of few Indian traditional herbal plants against Staphylococcus aureus biofilm along with phytochemical analysis of plant extracts and identification of active compounds. Broth micro-dilution method was followed for minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) study of the plants against Staphylococcus aureus ATCC 25923. Chitin was used as a substrate for biofilm formation and antibiofilm activity of plant extract was investigated. Scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FT-IR) of the chitin flakes were analysed to determine the inhibitory effect of the plant extract on Staphylococcus aureus biofilm. Curcuma longa showed the best antibacterial activities where MIC and MBC were 0.4 mg/ml and 1.60 mg/ml respectively. Viability cell counts of both planktonic and sessile condition of Staphylococcus aureus showed that C.longa ethanolic extract have an antibiofilm activity. The major compounds of C.longa extract was found to be curcumin, which responded for antibiofilm activity against S. aureus. Curcuma longa rhizome and its active compound curcumin can be a potential natural source of antibiofilm agents against infectious biofilm forming Staphylococcus aureus.

Selective enrichment of bacterial pathogens by microplastic biofilm

Microplastics have been found to be ubiquitous in freshwater ecosystems, providing a novel substrate for biofilm formation. Here, we incubated biofilm on microplastics and two natural substrates (rock and leaf) under a controlled environment to investigate the differences of microbial community structure, antibiotic resistance gene (ARG) profiles, and ARG microbial hosts between biofilms on three types of substrates. Results from high-throughput sequencing of 16S rRNA gene revealed that microplastic biofilm had a distinctive community structure. Network analyses suggested that microplastic biofilm possessed the highest node connected community, but with lower average path length, network diameter and modularity compared with biofilm on two natural particles. Metagenomic analyses further revealed microplastic biofilm with broad-spectrum and distinctive resistome. Specifically, according to taxonomic annotation of ARG microbial hosts, two opportunisitic human pathogens (Pseudomonas monteilii, Pseudomonas mendocina) and one plant pathogen (Pseudomonas syringae) were detected only in the microplastic biofilm, but not in biofilms formed on natural substrates. Our findings suggest that microplastic is a novel microbial niche and may serve as a vector for ARGs and pathogens to new environment in river water, generating freshwater environmental risk and exerting adverse impacts on human health.

Development of banana (Musa balbisiana) pseudo stem fiber as a surgical bio-tool to avert post-operative wound infections.

The search to develop an ideal suture material encourages us to explore novel suture biomaterials with superior characteristics to the current commercially available products. Surgical sutures play a crucial role in the development of post-operative wound infection by acting as a substrate for biofilm formation which leads to dehisced wounds. In this context, the present invention meets this need by fabricating banana (Musa balbisiana) fibre into an advanced antimicrobials releasing suture biomaterial (BSc) for the prevention of post-operative wound infection. Suture material developed from banana pseudo stem fiber was impregnated with chloramphenicol, clotrimazole and growth factors with the aid of a hydro-gel system. The fabricated suture material was found to be biocompatible towards human erythrocytes and L929 mouse fibroblast cells. BSc exhibited promising physico-chemical characteristics which were comparable to the commercially available Bombyx mori silk fibroin (BMSF) suture. BSc displayed a biphasic release pattern with sustained release of chloramphenicol for up to 140 h. Apart from being environment friendly and having a facile fabrication method, this advanced suture biomaterial showed broad spectrum in vitro antimicrobial activity against bacterial and fungal pathogens. BSc successfully impeded biofilm formation on its surface, as is evident from the confocal microscopy analysis. This contributes to superior wound healing efficacy in terms of reduced microbial burden and a subsequent decrease in the inflammatory cytokine levels. Histopathological observations further supported the pronounced healing efficacy of BSc sutured wounds. The findings of this study establish the banana pseudo stem fiber as a novel advanced suture biomaterial to prevent post-operative wound infections.

Printed paper-based arrays as substrates for biofilm formation

The suitability of paper-based arrays for biofilm formation studies by Staphylococcus aureus is demonstrated. Laboratory-coated papers with different physicochemical properties were used as substrates. The array platform was fabricated by patterning the coated papers with vinyl-substituted polydimethylsiloxane (PDMS) -based ink. The affinity of bacteria onto the flexographically printed hydrophobic and smooth PDMS film was very low whereas bacterial adhesion and biofilm formation occurred preferentially on the unprinted areas, i.e. in the reaction arrays. The concentration of the attached bacteria was quantified by determining the viable colony forming unit (CFU/cm2) numbers. The distribution and the extent of surface coverage of the biofilms were determined by atomic force microscopy. In static conditions, the highest bacterial concentration and most highly organized biofilms were observed on substrates with high polarity. On a rough paper surface with low polarity, the biofilm formation was most hindered. Biofilms were effectively removed from a polar substrate upon exposure to (+)-dehydroabietic acid, an anti-biofilm compound.

In vitroevaluation of natural and synthetic substrate for biofilm formation and their effect on water qualities

The present study evaluated the natural and synthetic substrate for biofilm formation in in vitro condition and their effect on physico-chemical parameters of water. The four different treatments i.e., control (without substrate), T1 (sugarcane bagasse), T2 (PVC), T3 (coconut husk) and T4 (bamboo strips) as substrates were used for assessment of biofilm formation and heterotrophic bacterial growth. Physico-chemical parameters of water and total platecolonies were estimated at weekly intervals for five weeks. Results of dissolved oxygen, total alkalinity, as well as nutrients like ammonia-nitrogen, nitrate-nitrogen and nitrite-nitrogen showed significant (p

Staphylococcus aureus biofilm formation and antibiotic susceptibility tests on polystyrene and metal surfaces

We compared the MBEC™-HTP assay plates made of polystyrene with metal discs composed of TMZF(®) and CrCo as substrates for biofilm formation. Staphylococcus aureus was grown on polystyrene and on metal discs made of titanium and chrome-cobalt. Antibiotic susceptibility was assessed by examining the recovery of cells after antibiotic exposure and by measuring the biofilm inhibitory concentration (BIC). The minimal inhibitory concentration (MIC) was assessed with planktonic cells. Bacterial growth was examined by scanning electron microscopy. The antibiotic concentration for biofilm inhibition (BIC) was higher than the MIC for all antibiotics. Microscopic images showed the biofilm structure characterized by groups of cells covered by a film. All models allowed biofilm formation and testing with several antibiotics in vitro. Gentamicin and rifampicin are the most effective inhibitors of Staph. aureus biofilm-related infections. We recommend MBEC™-HTP assay for rapid testing of multiple substances and TMZF(®) and CrCo discs for low-throughput testing of antibiotic susceptibility and for microscopic analysis. In vitro assays can improve the understanding of biofilms and help developing methods to eliminate biofilms from implant surfaces. One advantage of the TMZF(®) and CrCo discs as biofilm in vitro assay is that these metals are commonly used for orthopaedic implants. These models are usable for future periprosthetic joint infection studies.

Formation of natural biofilms during chlorine dioxide and u.v. disinfection in a public drinking water distribution system.

The influence of two disinfection techniques on natural biofilm development during drinking water treatment and subsequent distribution is compared with regard to the supply of a high-quality drinking water. The growth of biofilms was studied using the biofilm device technique in a real public technical drinking water asset. Different pipe materials which are commonly used in drinking water facilities (hardened polyethylene, polyvinyl chloride, steel and copper) were used as substrates for biofilm formation. Apart from young biofilms, several months old biofilms were compared in terms of material dependence, biomass and physiological state. Vital staining of biofilms with 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) and the DNA-specific 4',6-diamidino-2-phenylindole (DAPI) staining resulted in a significant difference in physiological behaviour of biofilm populations depending on the disinfection technique. Compared with chlorine dioxide disinfection (0.12-0.16 mg l-1), the respiratory activities of the micro-organisms were increased on all materials during u.v. disinfection (u.v.254; 400 J m-2). The biofilm biocoenosis was analysed by in situ hybridization with labelled oligonucleotides specific for some subclasses of Proteobacteria. Using PCR and additional hybridization techniques, the biofilms were also tested for the presence of Legionella spp., atypical mycobacteria and enterococci. The results of the molecular-biological experiments in combination with cultivation tests showed that enterococci were able to pass the u.v. disinfection barrier and persist in biofilms of the distribution system, but not after chlorine dioxide disinfection. The results indicated that bacteria are able to regenerate and proliferate more effectively after u.v. irradiation at the waterworks, and chlorine dioxide disinfection appears to be more applicative to maintain a biological stable drinking water. As far as the application of u.v. disinfection is used for conditioning of critical water sources for drinking water, the efficiency of u.v. irradiation in natural systems should reach a high standard to avoid adverse impacts on human health.