Microbial Viability Research Articles

The phenoxy-bearing naphthalimide substituted phthalocyanines: Photophysicochemical and biological properties

A new Si(IV) phthalocyanine (Pc) (1) derivative comprising axially phenoxy-bearing naphthalimide and peripherally t-butyl groups was synthesised and the photophysicochemical properties of this compound were investigated as an antioxidant and antimicrobial agent. Furthermore, the biological properties of the Si(IV) Pc compound (1) and its Zn(II) and Ga(III) Pc derivatives with a peripherally attached phenoxy-bearing naphthalimide group(2 and 3) were assessed in this study. While these compounds exhibited moderate antioxidant effects, their DNA nuclease activities were highly satisfactory. The compounds demonstrated effective antimicrobial activity, particularly following the photodynamic therapy. The most effective minimum inhibitory concentration value was obtained as 4 mg/L against E. faecalis and S. aureus. All compounds inhibited 100 % microbial cell viability at 125 mg/L. The biofilm formation ability of P. aeruginosa and S. aureus was significantly inhibited by all of the Pc compounds. Furthermore, experimental data were supported by TD-DFT calculations and NTO analyses, and the orbital densities of the compounds were shown.

Synthesis and biological properties of axially bis − (3,4,5-trimethoxybenzyloxy) phthalocyaninato silicon (IV)

In this study, bis − (3,4,5-trimethoxybenzyloxy) phthalocyaninato silicon (IV) was obtained from the reaction of 3,4,5-trimethoxybenzyl alcohol with SiPcCl2. This phthalocyanine was characterized using 1H NMR, FTIR, UV–vis and mass spectra. 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, antidiabetic, deoxyribonucleic acid (DNA) cutting, biofilm inhibition, anti-microbial and antimicrobial photodynamic therapy (aPDT) activities of newly synthesized bis − (3,4,5-trimethoxybenzyloxy) phthalocyaninato silicon (IV) molecule were studied. The best activities were 41.58 % at 100 mg/L for antioxidant and 41.66 % for antidiabetic at 400 mg/L concentration. The molecule degraded the biofilm matrix formed by Pseudomonas aeruginosa and Staphylococcus aureus as 78.61 % and 89.26 %, at 50 mg/L concentration, respectively. It was observed that E. coli, which was used as a model microorganism, was inhibited at a level close to 100 % even at the lowest concentration of 50 mg/L. While double strand break was observed at 50 mg/L DNA cutting activity, it was determined that DNA was reduced to nucleotides at 100 and 200 mg/L. The Pc also displayed effective antimicrobial and aPDT abilities against pathogens. With the application of aPDT, the effectiveness of antimicrobial activity increased 2 to 4 times. These increase rates are very important. The main conclusion of the study was that the newly synthesized compound exhibited various effective biological activities such as effective antioxidant, antidiabetic, DNA cleavage, antimicrobial, aPDT, biofilm inhibition and microbial cell viability inhibition.

Flow Cytometry Coupled with Resuscitation Assays As a High-Resolution Tool to Inform Environmental Management and Disinfection of Settings Affected by Tuberculous Mycobacteria.

Environmental decontamination and water disinfection practices are hallmarks of disease prevention and control in agricultural and public health settings. Informed fit-to-purpose biocontainment is thus dependent on methodologies accurately assessing microbial burden and viability. Also, rigorous evaluation of the efficacy of biocontrol measures implies monitoring microbial inactivation after decontamination/disinfection procedures. In this study, we used flow cytometry coupled with a resuscitation protocol to monitor the metabolic inactivation of bacteria capable of entering non-cultivable states, after the application of a chlorine-based water disinfectant. For this purpose, we used Mycobacterium bovis BCG as a model of slow-growing bacteria able to enter dormancy and representing a multi-host pathogen in a zoonotic disease system-animal tuberculosis-thriving both across temperate and semi-arid regions and involving environmental contamination. The biocide activity of a commercial sodium dichloroisocyanurate (NaDCC) disinfectant against M. bovis BCG was evaluated through mock environmental matrix tests. Using the manufacturer-recommended dosage of NaDCC, BCG cells were apparently inactivated after 24 h upon exposure. However, we show via flow cytometry that, upon exposure to optimal growth conditions, mycobacterial cells were able to regain metabolic activity shortly after, highlighting a sublethal effect of NaDCC at the recommended commercial dosage due to reversible BCG cell damage. In contrast, increasing twice the disinfectant dosage completely inactivated BCG cells after 24 h of exposure, with full irreversible loss of metabolic activity. Methodological workflows based on conventional culture or PCR would have missed the detection of these dormant subpopulations that were in fact able to resume growth when following the recommendations of a commercial disinfectant. This study highlights the superior, high-resolution value of single-cell approaches, such as flow cytometry, to accurately assess the activity of biocides against metabolically heterogeneous and dormant pathogenic bacteria with environmental cycles, supporting data-driven prioritization of environmental management and disinfection options in contaminated vulnerable settings.

Enhanced anti-biofilm and anti-caries potential of arginine combined with calcium glycerophosphate and fluoride

ObjectiveThe aim of this work was to evaluate the antibiofilm and anticaries properties of the association of arginine (Arg) with calcium glycerophosphate (CaGP) and fluoride (F). MethodsAn active attachment, polymicrobial biofilm model obtained from saliva and bovine teeth discs were used. After the initial biofilm growth period, the enamel discs were transferred to culture medium. The treatment solutions were added to the culture media to achieve the desired final concentration. The following groups were used: negative control (Control); F (110 ppm F); CaGP (0.05 %); Arg (0.8 %) and their associations (F + CaGP; Arg + F; Arg + CaGP; Arg +F + CaGP). The following analyses were carried out: bacterial viability (total bacteria, aciduric bacteria and mutans streptococci), pH assessment of the spent culture medium, dry weight quantification, evaluation of surface hardness loss (%SH) and subsurface mineral content. Normality and homoscedasticity were tested (Shapiro-Wilk and Levene's test) and the following tests were applied: two-way ANOVA (acidogenicity), Kruskall-Wallis (microbial viability) and one way ANOVA (dry weight, %SH, mineral content). ResultsThe association Arg + F + CaGP resulted in the lowest surface hardness loss in tooth enamel (-10.9 ± 2.3 %; p < 0.05). Arg +F + CaGP exhibited highest values of subsurface mineral content (10.1 ± 2.9 gHAP/cm3) in comparison to Control and F (p < 0.05). In comparison to Control and F, Arg +F + CaGP promoted the highest reduction in aciduric bacteria and mutans streptococci (5.7 ± 0.4; 4.4 ± 0.5 logCFU/mL, p < 0.05). ConclusionsThe Arg-F-Ca association demonstrated to be the most effective combination in protecting the loss of surface hardness and subsurface mineral content, in addition to controlling important virulence factors of the cariogenic biofilm. Clinical significanceOur findings provide evidence that the Arg-F-Ca association showed an additive effect, particularly concerning protection against enamel demineralization. The combination of these compounds may be a strategy for patients at high risk of caries.

Decrease of ESKAPE virulence with a cationic heme-mimetic gallium porphyrin photosensitizer: The Trojan horse strategy that could help address antimicrobial resistance

IntroductionEmerging antibiotic resistance among bacterial pathogens has forced an urgent need for alternative non-antibiotic strategies development that could combat drug resistant-associated infections. Suppression of virulence of ESKAPE pathogens' by targeting multiple virulence traits provides a promising approach. ObjectivesHere we propose an iron-blocking antibacterial therapy based on a cationic heme-mimetic gallium porphyrin (GaCHP), which antibacterial efficacy could be further enhanced by photodynamic inactivation. MethodsWe used gallium heme mimetic porphyrin (GaCHP) excited with light to significantly reduce microbial viability and suppress both the expression and biological activity of several virulence traits of both Gram-positive and Gram-negative ESKAPE representatives, i.e., S. aureus and P. aeruginosa. Moreover, further improvement of the proposed strategy by combining it with routinely used antimicrobials to resensitize the microbes to antibiotics and provide enhanced bactericidal efficacy was investigated. ResultsThe proposed strategy led to substantial inactivation of critical priority pathogens and has been evidenced to suppress the expression and biological activity of multiple virulence factors in S. aureus and P. aeruginosa. Finally, the combination of GaCHP phototreatment and antibiotics resulted in promising strategy to overcome antibiotic resistance of the studied microbes and to enhance disinfection of drug resistant pathogens. ConclusionLastly, considering high safety aspects of the proposed treatment toward host cells, i.e., lack of mutagenicity, no dark toxicity and mild phototoxicity, we describe an efficient alternative that simultaneously suppresses the functionality of multiple virulence factors in ESKAPE pathogens.

Effect of hydroxyapatite nanoparticles coating of titanium surface on biofilm adhesion: An in vitro study

AimTo evaluate the adhesion of mono and duospecies biofilm on a commercially available dental implant surface coated with hydroxyapatite nanoparticles (nanoHA). Material and methodsTitanium discs were divided into two groups: double acid-etched (AE) and AE coated with nanoHA (NanoHA). Surface characteristics evaluated were morphology, topography, and wettability. Mono and duospecies biofilms of Streptococcus sanguinis (S. sanguinis) and Candida albicans (C. albicans) were formed. Discs were exposed to fetal bovine serum (FBS) to form the pellicle. Biofilm was growth in RPMI1640 medium with 10% FBS and 10% BHI medium for 6 h. Microbial viability was evaluated using colony-forming unit and metabolic activity by a colorimetric assay of the tetrazolium salt XTT. Biofilm architecture and organization were evaluated by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). ResultsAE surface had more pores, while NanoHA had even nanoHA crystals distribution. Roughness was similar (AE: 0.59 ± 0.07 µm, NanoHA: 0.69 ± 0.18 µm), but wettability was different (AE: Θw= 81.79 ± 8.55°, NanoHA: Θw= 53.26 ± 11.86°; P = 0.01). NanoHA had lower S. sanguinis viability in monospecies biofilm (P = 0.007). Metabolic activity was similar among all biofilms. In SEM both surfaces on C. albicans biofilm show a similar distribution of hyphae in mono and duospecies biofilms. AE surface has more S. sanguinis than the NanoHA surface in the duospecies biofilm. CLSM showed a large proportion of live cells in all groups. ConclusionsThe nanoHA surface reduced the adhesion of S. sanguinis biofilm but did not alter the adhesion of C. albicans or the biofilm formed by both species.

Microorganisms and bacterial cellulose stability of Kombucha under different manufacture and storage conditions.

It is crucial to clarify the stability of Kombucha in the manufacture and storage stages due to the extensive study on the fermented products of Kombucha and the increase in the use of bacterial cellulose (BC). This study aimed to evaluate the stability of Kombucha in different manufacturing and storage temperatures within a certain time period. The stability of microorganisms and BC in Kombucha was investigated through regular replacement with the tea media at 28 and 25°C for manufacture, and the storage temperature of Kombucha was at 25, 4, and -20°C. Morphological observations of the BC in Kombucha ended at 28 and 25°C for manufacture and storage were performed using atomic force microscopy (AFM) before inoculation. The viable cell counts and AFM results showed that the stability of Kombucha during manufacture was better at 28°C than at 25°C, with higher microbial viability and BC productivity in the former at the time of manufacture, whereas 25°C was more favorable for the stability of Kombucha during storage. At the same temperature of 25°C, the manufacturing practice improved the microbial viability and BC stability compared with storage; the pH value of Kombucha was lower, and the dry weight of BC was higher during storage compared with manufacture. The maximum BC water holding capacity (97.16%) was maintained by storage at 4°C on day 63, and the maximum BC swelling rate (56.92%) was observed after storage at -20°C on day 7. The research was conducted to provide reference information for applying Kombucha and its BC in food and development in other industries.

The Syntheses of Chromium Aluminum Carbide (Cr2AlC) MAXPhase and Cr2CTx MXene and Investigation of Their Antimicrobial Properties.

Chromium aluminum carbide (Cr2AlC) MAX phase and Cr2CTx (MXene-Cr) were synthesized by the pressureless sintering method and hydrothermal method, respectively. In addition to this, the free radical scavenging activities (FRSA) of MAX-Cr phase and MXene-Cr compounds were tested and compared with ascorbic acid and trolox as standard compounds. The obtained FRSA results of MAX-Cr phase and MXene-Cr were 42.82 and 59.64%, respectively, at 100mg/L concentration. MXene-Cr showed a 66.90% inhibitory effect on α-amylase at 200mg/L. The DNA nuclease activity of compounds was determined to be extremely satisfactory at 50, 100, and 200mg/L concentrations. Moreover, the prepared MAX-Cr phase and MXene-Cr were investigated for antimicrobial activity against six bacterial and two fungal strains by the broth microdilution method. Compounds provided more significant inhibition against Gram-positive bacteria than Gram-negative bacteria and fungi. MAX-Cr phase and MXene-Cr almost completely inhibited microbial cell viability at a 25mg/L concentration. Additionally, MXene-Cr showed 89.86% and 87.01% antibiofilm activity against S. aureus and P. aeruginosa, respectively, while the antibiofilm activity of the MAX-Cr phase was over 90%.

Enhancing microbial viability with biochar for increased methane production during the anaerobic digestion of chicken manure

This investigation explores the effects of integrating acid-alkali treated biochar into the anaerobic digestion of chicken manure. Digesters containing chicken manure with biochar addition exhibited an 8.4-fold improvement in methane production compared to untreated digesters. In addition, the porous structure of the biochar promoted microbial acclimation, facilitated direct interspecies electron transfer, and provided anchoring points for immobilisation. Anaerobic digesters containing chicken manure amended with biochar also demonstrated increased chemical oxygen demand removal, up to 81.8 %, and maintained lower total ammonia concentrations (2,478 mg/L) compared to levels in control reactors (4418 mg/L). In terms of the microbial community, the addition of propidium monoazide minimised errors in live microbial population estimation, providing new insights into the capacity of biochar to shield microbes from ammonia stress. These findings highlight biochar's quantitative benefits, emphasising its potential in enhancing methane production, mitigating ammonia stress, and promoting microbial resilience in anaerobic digestion.

Microbial composition and viability of natural whey starters used in PDO Comté cheese-making

Natural whey starters (NWS) are cultures with undefined multiple-strains species commonly used to speed up the fermentation process of cheeses. The aim of this study was to explore the diversity and the viability of Comté cheese NWS microbiota. Culture-dependent methods, i.e. plate counting and genotypic characterization, and culture-independent methods, i.e. qPCR, viability-qPCR, fluorescence microscopy and DNA metabarcoding, were combined to analyze thirty-six NWS collected in six Comté cheese factories at two seasons. Our results highlighted that NWS were dominated by Streptococcus thermophilus (ST) and thermophilic lactobacilli. These species showed a diversity of strains based on Rep-PCR. The dominance of Lactobacillus helveticus (LH) over Lactobacillus delbrueckii (LD) varied depending on the factory and the season. This highlighted two types of NWS: the type-ST/LD (LD > LH) and the type-ST/LH (LD < LH). The microbial composition varied depending on cheese factory. One factory was distinguished by its level of culturable microbial groups (ST, enterococci and yeast) and its fungi diversity. The approaches used to estimate the viability showed that most NWS cells were viable. Further investigations are needed to understand the microbial diversity of these NWS.

Sourdough powder: physicochemical, microbiological properties and shelf-life stability in different package type.

This study aims to optimize the culture condition of semi-liquid sourdough using Kombucha as a starter culture and to evaluate the physicochemical properties, microbial viability and recovering ability of sourdough powder when packaged in different types of packaging for 120days. Optimal maturation time (103.47h) and maximum leavening rate (1.27mL/h) of sourdough were achieved at an incubation temperature of 34°C and interval refreshment time at 7h. The optimized culture was spray-dried using 3% Arabic gum (w/v) as a carrier agent yielding 35.86% powder with acceptable viability of 8.71 log CFU/g lactic acid bacteria and 9.03CFU/g yeast. The sourdough powder was packed in four packaging (LDPE, vacuumed LDPE, aluminum foil laminated pouch and vacuumed aluminum foil laminated pouch) and exhibited comparable physicochemical properties during 120days of storage. The viability of both lactic acid bacteria and yeast count in sourdough powder when packed in vacuumed aluminum foil laminated pouch showed higher stability for 90days (6.18 log CFU/g and 6.82 log CFU/g) but reduced to below detection limit after 120days (5.54 and 5.94 log CFU/g). This suggested that Kombucha sourdough powder packed in vacuumed aluminum laminated pouch could be stored for up to 90days.

Microbial viability and nutritional content of water kefir grains under different storage conditions.

Water kefir grains are an important source of probiotics, mainly containing lactic acid bacteria and yeasts. The aim of this study is to investigate the changes in microbial and chemical properties of water kefir grains during 1-month storage at +4°C and -18°C. The initial content of lactobacilli, lactococci, and yeast in water kefir grains was 6.06, 6.33, and 5.93 log CFU/g, respectively. The number of lactobacilli, Lactobacillus acidophilus, and Bifidobacterium spp. in the water kefir grains were comparable, with slight changes at the end of refrigerated storage (p > .05). Lactococci and yeasts decreased significantly after both storage conditions compared to the initial content (p < .05). The dry matter and ash contents remained unchanged during storage (p > .05). Water kefir grains contained significant amounts of calcium, vitamin B2, vitamin B6, vitamin B7, and vitamin B12. Storage at both +4°C and -18°C did not affect the mineral and vitamin contents, except for Cu and Vitamin B2. The results indicate that the water kefir grains remained viable after storage at both temperatures. If water kefir grains need to be stored, it is recommended to store them at +4°C in sugared water as it ensures better survivability of the microbiota of the grains.

Investigation of advanced biological properties of carbon, carbon‐boron quantum dots, and copper (II) phthalocyanine nanoconjugates

Non‐peripherally, glycerol terminal groups substituted copper (II) phthalocyanine were non‐covalently (electrostatic and/or π–π interaction) attached to carbon (CQD) and carbon‐boron quantum dots (CBQD) to form QDs‐Pc nanoconjugate systems. Synthesized novel phthalocyanine compounds and QDs‐Pc conjugate systems were characterized using different spectroscopic techniques. Various biological assessments were applied to newly synthesized compounds. Conjugates 4 and 5 had a maximal free radical scavenging activity of 71.3% and 68.1% at a 100 mg/L concentration. Compounds exhibited high antidiabetic activities at 200 mg/L. Also, compounds showed significant DNA nuclease activity at all tested concentrations. The most efficient MIC value was obtained as 4 mg/L against Enterococcus hirae and Enterococcus feacalis. This MIC value was further decreased after photodynamic therapy, and it was observed that the antimicrobial effects of the compounds increased. Inhibition of microbial cell viability was obtained as 100% for all compounds. In addition, compounds exerted perfect biofilm inhibitory effects.

Functional benefits of probiotic fermented dairy drink elaborated with sheep milk processed by ohmic heating

This study examined the effects of ohmic heating pasteurization on probiotic fermented sheep milk compared to conventional heating by analyzing microbial viability, volatile compounds, riboflavin content, and bioactive peptides in the resulting dairy product. Four batches of milk were processed using conventional heating (CH) and three different ohmic heating (OH). Microbiological analysis demonstrated the safety of OH-processed milk. Probiotic viability remained consistent during fermentation and storage, and the simultaneous inoculation of bacteria reduced fermentation time, indicating cooperation interplays. OH-processed probiotic fermented sheep milk showed a substantial increase in antioxidant, antidiabetic, antihypertensive activities, and riboflavin content. Moreover, the flavor profile was characterized by specific volatile compounds. Multiple-factor analysis was performed to identify relationships between samples and various parameters, offering insights into the impact of processing methods. In conclusion, OH enhanced the health-promoting and flavor-related compounds of probiotic fermented sheep milk, suggesting its application to produce functional dairy products.

Effects of photodynamic therapy in patients with infected skin ulcers: A meta-analysis.

The purpose of the meta-analysis was to evaluate and compare the photodynamic therapy's effectiveness in treating infected skin wounds. The results of this meta-analysis were analysed, and the odds ratio (OR) and mean difference (MD) with 95% confidence intervals (CIs) were calculated using dichotomous or contentious random- or fixed-effect models. For the current meta-analysis, 6 examinations spanning from 2013 to 2021 were included, encompassing 154 patients with infected skin wounds were the used studies' starting point. Photodynamic therapy had a significantly lower wound ulcer size (MD, -4.42; 95% CI, -7.56--1.28, p = 0.006), better tissue repair (MD, -8.62; 95% CI, -16.76--0.48, p = 0.04) and lower microbial cell viability (OR, 0.13; 95% CI, 0.04-0.42, p < 0.001) compared with red light exposure in subjects with infected skin wounds. The examined data revealed that photodynamic therapy had a significantly lower wound ulcer size, better tissue repair and lower microbial cell viability compared with red light exposure in subjects with infected skin wounds. However, given that all examinations had a small sample size, consideration should be given to their values.

Investigating the stability of vitamin D3 and Bifidobacterium lactis nanoparticles coated with polycaprolactone-polyethylene glycol-polycaprolactone triblock copolymer in Iranian white cheese and determining its physicochemical and sensory properties

ObjectiveTo investigate the stability and efficacy of vitamin D3 and Bifidobacterium lactis nanoparticles coated with polycaprolactone-polyethylene glycol-polycaprolactone (PCL-PEG-PCL) in enhancing the nutritional value of Iranian white cheese and to assess their impact on the cheese's physicochemical and sensory properties. MethodsBifidobacterium lactis and vitamin D3 were encapsulated using PCL-PEG-PCL. The particle size was analyzed using Dynamic Light Scattering (DLS). Five different cheese groups were produced and analyzed over two months. This included assessing microbial viability in simulated gastric and intestinal environments, quantifying vitamin D3 content, and evaluating physicochemical and sensory characteristics using a 9-point hedonic scale. ResultsThe Cheese with Bifidobacterium lactis coated with PCL-PEG-PCL and vitamin D3 nanoparticles (BCND3), showed a marked improvement in the stability of both Bifidobacterium lactis and vitamin D3. Specifically, the coated bacteria maintained a concentration of 106 cfu/g until day 45 in the intestinal model, demonstrating effective protection against the acidic gastric environment. The vitamin D3 nanoparticles displayed enhanced stability within the cheese matrix, contributing to the nutritional value and potentially extending the shelf life. Physicochemically, initial pH reduction due to lactic acid production stabilized by day 60, aligning with other groups. Sensory evaluation revealed a preference for the softer texture of cheese with vitamin D3 nanoparticles, suggesting a positive impact on consumer acceptability. ConclusionThe application of PCL-PEG-PCL coating significantly improved the stability of probiotics and vitamin D3 in cheese. This method proved effective in protecting Bifidobacterium lactis from harsh gastrointestinal conditions and in sustaining vitamin D3 content, with a notable impact on the cheese's sensory qualities. These findings highlight the potential of this coating technique in food fortification strategies.

A21 EFFECTS OF LYOPHILIZED FECAL FILTRATE COMPARED TO LYOPHILIZED DONOR STOOL IN THE TREATMENT OF RECURRENT CLOSTRIDIOIDES DIFFICILE INFECTION: A MULTI-CENTER RANDOMIZED TRIAL

Abstract Background Fecal microbiota transplantation (FMT) is the most effective therapy in the treatment of recurrent Clostridioides difficile infection (rCDI), and can be offered in fresh, frozen or lyophilized formulation with similar efficacy. Microbial engraftment is thought to be one of the mechanisms mediating its efficacy. However, the importance of microbes has been questioned by two small preliminary clinical studies that showed sterile fecal filtrate could prevent C. difficile recurrence. Aims To establish whether lyophilized sterile fecal filtrate (LSFF) is noninferior to lyophilized FMT (LFMT) in efficacy Methods In this double-blind, non-inferiority study conducted in 4 academic centers in Alberta and British Columbia, we randomized rCDI patients with ≥ 3 CDI episodes to either LSFF or LFMT at a 1:1 ratio between 2019 and 2023.The non inferiority margin was 10%. Each treatment dose consisted of 15 oral capsules. Participants who failed the assigned treatments were offered open-label LFMT. An interim analysis was planned after reaching 50% of recruitment target (124/248 participants). Primary outcome was the proportion of participants without CDI recurrence 8 weeks following assigned treatment. Secondary outcomes included 1) the proportion of participants without CDI recurrence 24 weeks following assigned treatment, 2) serious adverse events (mortality, hospitalization and infections related to treatments), and 3) minor adverse events (nausea, vomiting, abdominal pain and fever). Exploratory outcomes included changes in quality of life, stool microbial composition analyses, as well as patient preferences. Results 137 participants were randomized (mean [SD] age, 61.2 [18.6] years; 89 women [65.4%]; mean CDI episodes 3.8) to LFMT group (66 participants) and LSFF (71 participants) group. In per-protocol analysis, prevention of rCDI 8 weeks after assigned treatment was achieved in 63.8% of participants in LSFF group and 86.9% in LFMT group (difference, -23.1%), resulting in trial termination. Serious adverse events were infrequent: 4 hospitalizations deemed not related and 1 hospitalization possibly related, and 1 death from COVID deemed not related to assigned treatment. Minor adverse events were self-limited and infrequent: nausea (6), vomiting (2), abdominal discomfort (15) and fever (2). Conclusions Among adults with rCDI, LSFF was inferior to LFMT by oral capsules in preventing recurrent infection over 8 weeks. The result emphasizes the importance of microbes in mediating FMT efficacy. Preserving microbial viability in future development of microbial therapeutics is paramount. Funding Agencies CIHR

Ultraviolet C as a method of disinfecting medical silicone used in facial prostheses: An in vitro study – Part 2

Statement of problemDisinfection is an important factor in preserving facial prostheses and maintaining tissue health. However, whether disinfection with ultraviolet C is an effective disinfection method is unclear. PurposeThe purpose of this in vitro study was to evaluate the effectiveness of irradiation with different exposure durations of an ultraviolet-C light-emitting diode in the disinfection of the silicone (A-588–1; Factor II) used in facial prostheses. Material and methodsA total of 216 specimens were prepared, contaminated by multispecies biofilm, and divided into 9 groups (n=24) for different treatments: chlorhexidine 0.12% (G CHG), ultraviolet-C light-emitting diode for 5 minutes (G UVC5), ultraviolet-C light-emitting diode for 10 minutes (G UVC10), ultraviolet-C light-emitting diode for 20 minutes (G UVC20), their respective untreated controls (Gcontrol CHG, Gcontrol UVC5, Gcontrol UVC10, Gcontrol UVC20), and dimethyl sulfoxide (G DMSO) as the negative control. Cell viability was measured by using the methyl tetrazolium salt (MTT) method. Two statistical analyses were performed. First, a 2×3 ANOVA was carried out to compare the control groups (Gcontrol UVC5, Gcontrol UVC10, and Gcontrol UVC20) and the experimental groups of UV-C LED light with different exposure durations (G UVC5, G UVC10, and G UVC20). The second analysis was performed using generalized linear models to compare the optical density of the groups (G UVC5, G UVC10, G UVC20, G CHG, and G DMSO). ResultsCell viability results demonstrated a microbial reduction after exposure to the ultraviolet-C light-emitting diode for 20 minutes (G UVC20) compared with untreated controls (P<.05). The 5- and 10-minute exposures were statistically similar to their respective control groups (P>.05). The 20 minutes exposure had the lowest average optical density value, being statistically different from the 5-minute exposure (P<.05). A 20-minute exposure to the ultraviolet-C light-emitting diode (G UVC20) was similarly effective when compared with the standard disinfection treatment (G CHG) and dimethyl sulfoxide (G DMSO) (P>.05). ConclusionsIrradiation with an ultraviolet-C light-emitting diode for 20 minutes decreased the in vitro microbial cell viability on the medical silicone used in facial prostheses.

Synthesis of CaO-Fe and CaO-Ag nanocomposites using raw and hydrolyzed waste chicken eggshell and investigation of their antimicrobial, biofilm inhibition activity, DNA cleavage ability, and antioxidant activity properties

AbstractIn this study, CaO-Fe and CaO-Ag nanocomposites were synthesized and various biological properties were characterized. E. coli cell viability, antimicrobial, antioxidant, antibiofilm, and DNA cleavage properties were examined. All nanocomposites, namely raw CaO-Ag (R-CaO-Ag), hydrolyzed CaO-Ag (H-CaO-Ag), raw CaO-Fe (R-CaO-Fe), and hydrolyzed CaO-Fe (H-CaO-Fe), were found to have good antioxidant, antimicrobial, and antibiofilm properties. They showed antioxidant activity of 83.33%, 70.60%, 74.73%, and 72.78%, respectively, at 200 mg/L nanocomposites. When DNA cleavage properties of R-CaO-Ag, H-CaO-Ag, R-CaO-Fe, and H-CaO-Fe were evaluated at different concentrations, single-strand break was observed for all samples. It was shown that R-CaO-Ag was more effective against S. aureus and C. tropicalis, and H-CaO-Ag was more effective against E. hirae. It was found that the antimicrobial activities of R-CaO-Ag and H-CaO-Ag were higher compared to R-CaO-Fe and H-CaO-Fe. The microbial cell viability of nanocomposites was examined at three different concentrations. Even at the lowest concentration (125 mg/L), high values of E. coli inhibition were found as 98.65%, 100%, 90.24%, and 88.63%, respectively. Also, it was observed that all nanocomposites exhibited excellent biofilm inhibition activities. The antibiofilm abilities of one Gr (+) and one Gr (−) microorganism at three different concentrations were investigated. Biofilm inhibition percentages of R-CaO-Ag, H-CaO-Ag, R-CaO-Fe, and H-CaO-Fe were found as 65.83%, 86.5%, 89.67%, and 93.62% for S. aureus at 500 mg/L, respectively, while it was 50.06%, 90.68%, 71.69%, and 92.36% for P. aeruginosa, respectively, at 500 mg/L.

Effect of Pediococcus acidilactici and mango seed polyphenols on the fermentative profile of the indigestible fraction of yam bean

Yam bean is an important source of dietary fiber and other components that comprise the total indigestible fraction (TIF), which can be fermented by the colonic microbiota and produce metabolites with beneficial health effects. Therefore, the objective of this study was to evaluate the in vitro colonic fermentation of yam bean TIF and the changes caused by the addition of a polyphenolic extract of mango seed and the lactic acid bacteria Pediococcus acidilactici. The mango seed extract was obtained by ultrasound-assisted extraction, and the microbial growth rate and viability of P. acidilactici were determined using a Neubauer chamber. Yam bean TIF was isolated by triple enzymatic hydrolysis and subjected to in vitro colonic fermentation in combination with treatments with mango seed extract and P. acidilactici suspensions. Changes in pH, total soluble phenols (TSP), and antioxidant capacity (AOX) were evaluated. Furthermore, the production of metabolites was quantified by HPLC-DAD-MS and GC–MS. The Growth rate of P. acidilactici was 0.1097 h−1 with 97.5 % viability at 7 h of incubation. All TIF treatments showed a high capacity of fermentation, and the addition of mango seed extract increased the TSP content and AOX in DPPH and FRAP assays. A total of Forty-six volatile metabolites were detected, with highlighting the presence of esters, benzenes, aldehydes, and short-chain fatty acids. Five phenolic compounds associated with mango by-products were quantified during all fermentation process, despite the concentration of the extract. P. acidilactici did not substantially modify the fermentative profile of TIF. However, further studies such as the evaluation of the abundance of microbial communities may be necessary to observe whether it can generate changes during colonic fermentation.