Moistube irrigation fouling due to anaerobic filtered effluent (AF) and horizontal flow constructed wetland (HFCW) effluent

The study assessed the suitability of two effluent types, namely anaerobic filtered (AF) and horizontal flow constructed wetland (HFCW) effluent for Moistube irrigation (MTI). Secondary to this, the study determined the plugging coefficients (α) on MTI for the respective effluents. The feed water was supplied from a raised tank (3.5 m), and mass-flow rates were recorded at 15 min intervals using an electronic balance. The effluent feed water concentrations and experimental room temperature (25 °C ± 1 °C) were continuously monitored and kept constant. Hermia’s models based on the $${\text{R}}^{2}$$ R 2 coefficient was used to select the best fitting fouling mechanism model and, consequently, the plugging coefficients. In addition, microbial colony analysis and scanning electron microscopy (SEM) analysis was carried out to assess the composition of the deposited sediment (DS) and adhered bacterial film (ABF) onto the MTI lateral. The study revealed that MTI pore blocking was a complex phenomenon described by complete pore-blocking model ($${\text{R}}^{2}$$ R 2 ≥ 0.50). Discharge followed an exponential decay with early fouling observed on AF effluent because of a high concentration of total suspended solids (TSS) and dissolved organic matter (DOM). Discharge declined by 50% after 20 and 10 h of intermittent operation for AF and HFCW effluent, respectively. The α for each effluent (foulant) were $$\alpha_{AF}$$ α AF = 0.07 and $$\alpha_{ HFCW}$$ α HFCW = 0.05, respectively, for AF and HFCW. The microbial analysis revealed bacterial aggregation structures that contributed to pore blocking. SEM imaging revealed complete surface coverage by deposited sediment. It is concluded that water quality determines the operation life span of MTI, and the two effluents promote accelerated MTI pore fouling or blocking. Continuous use without flushing the MTI will promote membrane degradation and reduced discharge efficiency. Additional filtration can potentially mitigate the membrane degradation process.

Preparation and of PVA-based compositions with embedded silver, copper and zinc oxide nanoparticles and assessment of their antibacterial properties

A series of poly(vinyl alcohol) (PVA) based liquid compositions with addition of zinc oxide, silver and copper nanoparticles has been prepared. The compositions also contained other consistency-forming organic components. The physico-chemical properties of the products have been determined. Their pH and density have been assessed. Also, the size of nanoparticles has been defined with using a dynamic light scattering technique. The compositions were subjected to XRD, FT-IR and microscopic analysis as well. Thanks to the incorporation of both metal oxide and metallic nanoparticles, it was possible to enrich the products with antibacterial properties. Their inhibiting properties in the growth of microorganisms have been confirmed against both Gram-negative and Gram-positive strains such as E. coli, S. aureus and P. aeruginosa. Thanks to the ability for solidification, the compositions may be applied on a bacterially contaminated surface, and after destroying the microorganisms and its solidification, it may be peeled off along with the dead bacterial film.

Antimicrobial and Antibiofilm Properties of Graphene Oxide on Enterococcus faecalis

The aim of this study was to evaluate the antibacterial properties of graphene oxide (GO) against Enterococcus faecalis in vitro conditions and when used to coat dentin surface to prevent E. faecalis adhesion. The ATCC strain of E. faecalis 29212 has been used to perform a viability test. The pellet was suspended in ultrapure water, NaCl, PBS buffer, CaCl2 and MgCl2, Luria−Bertani broth solutions. The viability was evaluated by the colony forming unit counting method. Atomic force microscopy images and the measure of surface zeta potential variation were analyzed. Dentin discs were covered with a film of GO (n = 15) or were not treated (n = 15). Bacterial suspension was added to each sample of dentine discs and microbial counts were calculated. Statistically significant differences between two groups were assessed by a two-tailed unpaired t-test. Bacteria cell morphology was investigated with scanning electron microscopy. The highest growth inhibition was obtained in ddH2O and CaCl2 solution while, in PBS and NaCl, GO had poor antibacterial efficacy with a growth enhancing effect in the latter. GO on dentin discs demonstrated high antibacterial activity. GO film has demonstrated acceptable adhesion properties to root dentin and a role in the inhibition of bacterial film proliferation and biofilm formation.

CaSiO3-HAp Structural Bioceramic by Sol-Gel and SPS-RS Techniques: Bacteria Test Assessment

The article presents an original way of getting porous and mechanically strong CaSiO3-HAp ceramics, which is highly desirable for bone-ceramic implants in bone restoration surgery. The method combines wet and solid-phase approaches of inorganic synthesis: sol-gel (template) technology to produce the amorphous xonotlite (Ca6Si6O17·2OH) as the raw material, followed by its spark plasma sintering–reactive synthesis (SPS-RS) into ceramics. Formation of both crystalline wollastonite (CaSiO3) and hydroxyapatite (Ca10(PO4)6(OH)2) occurs “in situ” under SPS conditions, which is the main novelty of the method, due to combining the solid-phase transitions of the amorphous xonotlite with the chemical reaction within the powder mixture between CaO and CaHPO4. Formation of pristine HAp and its composite derivative with wollastonite was studied by means of TGA and XRD with the temperatures of the “in situ” interactions also determined. A facile route to tailor a macroporous structure is suggested, with polymer (siloxane-acrylate latex) and carbon (fibers and powder) fillers being used as the pore-forming templates. Microbial tests were carried out to reveal the morphological features of the bacterial film Pseudomonas aeruginosa that formed on the surface of the ceramics, depending on the content of HAp (0, 20, and 50 wt%).

Effect of Polyols and Selected Dental Materials on the Ability to Create a Cariogenic Biofilm–On Children Caries-Associated Streptococcus Mutans Isolates

Secondary caries is a disease associated with the formation of biofilm on the border of the tooth and dental filling. Its development is strongly influenced by the dietary sweet foods and the type of dental material. The aim of the study was to assess the effect of sweeteners on the ability of clinical Streptococcus mutans strains to form biofilm on dental materials. Strains were isolated from plaque samples from 40 pediatric patients from the 3–6 ICADS II group. The ability to form biofilm was tested on composite and glass ionomer dental materials used for milk teeth filling in the presence of sucrose, xylitol, sorbitol, and erythritol. The bacterial film mass after 12, 24, 48, and 72 h and the number of bacterial colonies significantly decreased (p < 0.01) compared to the initial value for 5% erythritol and sorbitol on examined materials. A greater inhibitory effect was noted for glass ionomers compared to composites. Sucrose and xylitol supported biofilm formation, while erythritol had the best inhibitory effect. The use of fluoride-releasing glass ionomers exerted an effect synergistic to erythritol, i.e., inhibited plaque formation and the amount of cariogenic S. mutans. Selection of proper type of dental material together with replacing sucrose with polyols can significantly decrease risk of secondary caries development. Erithritol in combination with glass ionomer seems to be the most effective in secondary caries prevention.

Research of antimicrobial efficacy of a composition with prolonged antiseptic effect against planktonic and film forms of clinical strains of non-fermentative Gram-negative bacteria

Annotation. The problem of treatment of burn wounds is closely related to the specificity of the spectrum of microorganisms that impair wound healing in this category of patients. A generally alarming trend in recent years is the significant increase in the etiological structure of wound infection, both in frequency and in severity and in the difficult choice of treatment tactics in the isolation of poly antimicrobial resistant strains of Pseudomonas aeruginosa, Acinetobacter baumannii. The aim of our study was to create a model of biofilm formed by bacteria on the wound surface and to investigate, in a comparative study, the sensitivity of planktonic and film forms of non-enzymatic gram-negative bacteria to a composition based on decamethoxin with prolonged antiseptic action. To determine the effect of the antiseptic composition on planktonic and film forms of bacteria there was used the method of two consecutive dilutions. The results of a comparative study of the activity of the antiseptic composition with decamethoxin planktonic and biofilm forms of strains of NFGB indicated that in the bacterial film bacteria were more resistant to drugs than in planktonic form. Film forms of A. baumannii and B. cepacia have a sensitivity to decamethoxin at a concentration of 13.6±1.95 µg/ml and 15.6±0 µg/ml, respectively. P. aeruginosa film forms have a higher degree of resistance to the test composition with decamethoxin (MBc 137.5±30.6 μg/ml). Disinfection of the planktonic form of NFGB is 10 times faster than the film form, the destruction of which is achieved with prolonged exposure of 120–150 minutes.

New Opportunities in the Diagnosis of the Implant-Associated Infection

Summary. Despite the improvement in the quality of implants, the number of complications in traumatology and orthopedics, which lead to infection, remains high. It is proved that untimely prescription of adequate antibiotic therapy for implant-associated infections can cause progression of the septic process until the development of shock and multiorgan failure and on practics leads to the development of resistance microorganisms to antibacterial drugs. An important point is to study the pathological microbial communities (bacterial film) in traumatology and orthopedics. All "classic" tests and markers of the infectious processhave low specificity and are not reliable enough for accurate diagnosis. These features are forced to development of additional microbiological diagnostics: the study of the destruction of the biofilm, which is removed from the implant surface with the help of ultrasound. The purpose of our study was to determine the effectiveness of the microbiological tests with sonication in patients with infectious process after osteosynthesis of long bones. Materials and Methods. Microbiological studies of the pathologically altered tissue biopsies directly at the implant and implant sonicates from the implant for osteosynthesis from 31 patients with chronic osteomyelitis or surgical site infection were performed. Results. As a result, the significant sonication efficiency was discovered: a 25.8% increase in positive results, 6.5% of E. aerogenes and E. faecalis cultures in association with S. aureus were isolated. Conclusions. Further improvement of the method and its application in specialized departments can give a positive diagnostic effect, which will subsequently improve the results of patient treatment.

Bacterial film disintegration with electrochemically reduced water

This work aimed to study the fine structure of bacterial films grown on the inner tuber surface of flow reactor. Applying scanning electron microscopy (SEM) approaches, the detailed biofilm relief was visualized. The action of electrochemically reduced water (ERW) on the biofilm ultrastructure generated by the plankton form of E.coli and/or lacto bacteria was investigated. Treatments with an ERW solution were exhibited to destroy the biofilm organic polymer matrix and bacterial cells embedded in a matrix.