Viable Bacterial Counts Research Articles

Effects of pretreated garlic on bacterial composition and metabolite profiles during kimchi fermentation

This study investigated the effects of pretreated garlic on the fermentation characteristics of kimchi; four types of kimchi using pretreated garlic [raw (RGK), frozen (FGK), blanched (BGK), and blanched-frozen (BFGK)] were prepared; fermentation was carried out at 4 °C for 6 weeks. The fermentation properties, microbial community composition, metabolic compounds, and volatile organic compounds (VOC) were investigated. The total viable bacterial count in blanched garlic was reduced significantly compared to those in raw and frozen garlic. Latilactobacillus spp. became the dominant species in all kimchi samples as the fermentation progressed. Of the 145 metabolites observed by gas chromatography and mass spectrometry, 51 volatile metabolites were observed. Glucose, fructose, sucrose, lactic acid, citric acid, and mannitol were present as major metabolites (variable importance in projection scores >1.0). Frozen garlic (FGK and BFGK) reduced the production of sulfuric VOC compounds, while raw garlic increased the production of these compounds, specifically that of allyl methyl sulfide, dimethyl disulfide, and dimethyl trisulfide. In conclusion, the condition of garlic added to kimchi affects the abundance of microorganisms during initial fermentation and the quality characteristics of kimchi during the fermentation period. These results help establish garlic pretreatment conditions for kimchi manufacturing.

Cellulase with Bacillus velezensis improves physicochemical characteristics, microbiota and metabolites of corn germ meal during two-stage co-fermentation.

Corn germ meal (CGM) is one of the major byproducts of corn starch extraction. Although CGM has rich fiber content, it lacks good protein content and amino acid balance, and therefore cannot be fully utilized as animal feed. In this study, we investigated the processing effect of cellulase synergized with Bacillus velezensis on the nutritional value of pretreated CGM (PCGM) in two-stage solid-state fermentation (SSF). High-throughput sequencing technology was used to explore the dynamic changes in microbial diversity. The results showed that compared with four combinations of B. velezensis + Lactiplantibacillus plantarum (PCGM-BL), cellulase + L. plantarum (PCGM-CL),control group (PCGM-CK), and cellulase + B. velezensis + L. plantarum (PCGM-BCL), the fourth combination of PCGM-BCL significantly improved the nutritional characteristics of PCGM. After two-stage SSF (48h), viable bacterial count and contents of crude protein (CP) and trichloroacetic acid-soluble protein (TCA-SP) all were increased in PCGM-BCL (p < 0.05), while the pH was reduced to 4.38 ± 0.02. In addition, compared with PCGM-BL, the cellulose degradation rate increased from 5.02 to 50.74%, increasing the amounts of short-chain fatty acids (216.61 ± 2.74 to 1727.55 ± 23.00µg/g) and total amino acids (18.60 to 21.02%) in PCGM-BCL. Furthermore, high-throughput sequencing analysis revealed significant dynamic changes in microbial diversity. In the first stage of PCGM-BCL fermentation, Bacillus was the dominant genus (99.87%), which after 24h of anaerobic fermentation changed to lactobacillus (37.45%). Kyoto Encylopaedia of Genes and Genomes (KEGG) metabolic pathway analysis revealed that the pathways related to the metabolism of carbohydrates, amino acids, cofactors, and vitamins accounted for more than 10% of the enriched pathways throughout the fermentation period. Concisely, we show that cellulase can effectively improve the nutritional value of PCGM when synergized with B. velezensis in two-stage SSF.

Screening, Characterization and Probiotic Properties of Selenium-Enriched Lactic Acid Bacteria

Considerable progress has been achieved in the bioaccumulation and transformation of selenium (Se)-enriched lactic acid bacteria (LAB). However, research on the effects of Se on the structure and probiotic potential of LAB is relatively limited. In this study, six industrial LAB strains, including Lactobacillus plantarum 21,805, Lactobacillus paracasei 20,241, Lactobacillus fermentum 21,828, Lactobacillus casei 23,185, Lactobacillus acidophilus 6064, and Lactobacillus plantarum 6076, were cultured in De Man, Rogosa, and Sharpe (MRS) medium containing Se for three generations. High-Se LAB was screened based on bacterial biomass, viable bacterial count, and Se content. Their structural characteristics were analyzed using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The results indicated that LAB growth was influenced by the Se environment, with high Se (20 μg/mL) inhibiting it. At a Se concentration of 10 μg/mL, LAB maintained integrity and exhibited a high Se enrichment ability, with a Se enrichment of 4.88 ± 0.39 mg/g. The intracellular Se existed in an amorphous or non-crystalline form. Furthermore, Se-enriched LAB exhibited enhanced probiotic properties, including tolerance to simulated gastrointestinal fluids, acid resistance, bile salt resistance, and hydrophobicity. Therefore, Se-enriched LAB are expected to develop new functional foods or dietary supplements for human and animal consumption.

Biofouling on titanium implants: a novel formulation of poloxamer and peroxide for in situ removal of pellicle and multi-species oral biofilm.

Eradicating biofouling from implant surfaces is essential in treating peri-implant infections, as it directly addresses the microbial source for infection and inflammation around dental implants. This controlled laboratory study examines the effectiveness of the four commercially available debridement solutions '(EDTA (Prefgel®), NaOCl (Perisolv®), H2O2 (Sigma-Aldrich) and Chlorhexidine (GUM® Paroex®))' in removing the acquired pellicle, preventing pellicle re-formation and removing of a multi-species oral biofilm growing on a titanium implant surface, and compare the results with the effect of a novel formulation of a peroxide-activated 'Poloxamer gel (Nubone® Clean)'. Evaluation of pellicle removal and re-formation was conducted using scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy to assess the surface morphology, elemental composition and chemical surface composition. Hydrophilicity was assessed through contact angle measurements. The multi-species biofilm model included Streptococcus oralis, Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans, reflecting the natural oral microbiome's complexity. Biofilm biomass was quantified using safranin staining, biofilm viability was evaluated using confocal laser scanning microscopy, and SEM was used for morphological analyses of the biofilm. Results indicated that while no single agent completely eradicated the biofilm, the 'Poloxamer gel' activated with 'H2O2' exhibited promising results. It minimized re-contamination of the pellicle by significantly lowering the contact angle, indicating enhanced hydrophilicity. This combination also showed a notable reduction in carbon contaminants, suggesting the effective removal of organic residues from the titanium surface, in addition to effectively reducing viable bacterial counts. In conclusion, the 'Poloxamer gel + H2O2' combination emerged as a promising chemical decontamination strategy for peri-implant diseases. It underlines the importance of tailoring treatment methods to the unique microbial challenges in peri-implant diseases and the necessity of combining chemical decontaminating strategies with established mechanical cleaning procedures for optimal management of peri-implant diseases.

Extrusion bond strength and disinfection of E. faecalis from canal dentin using synchronized microbubble photodynamic activation and photon-induced photoacoustic streaming.

This study aimed to assess the antimicrobial effectiveness of a new disinfection regimen Curcumin photosensitizer (CP), Synchronized Microbubble Photodynamic Activation (SYMPA), Photon-induced photoacoustic streaming (PIPS), and its impact on the extrusion bond strength (EBS) of root filling material to canal dentin. Root canal treatments of sixty mandibular incisors were performed, and an overnight culture of E. faecalis was cultivated in the BHI medium. A volume of 1 mL was introduced into twenty root canals. All the samples were randomly allocated into 4 groups based on the irrigation used: -Group 1: 2.5% NaOCl+17% EDTA (Control), Group 2: CP+17% EDTA, Group 3: SYMPA+17% EDTA, and Group 4: PIPS+17% EDTA. The viable bacterial count was estimated, and 15 specimens from each group were obturated, followed by sectioning in 1-mm thick slices. The EBS was measured using a universal testing machine, and failure modes were analyzed using a stereomicroscope at 40x magnification. Means and standard deviations (SD) of the survival rate of E. faecalis and EBS of root filling to the dentin were analyzed using ANOVA Tukey multiple comparison t-tests (p=0.05). Group 1 (2.5% NaOCl+17% EDTA) demonstrated the highest survival rate of E. faecalis. Group 3, in which SYMPA+17% EDTA was used to sterilize the canal, unveiled the lowest survival rate (1.55±0.11 CFU/mL). Similarly, the coronal section of Group 3 specimens (8.67±0.43MPa) demonstrated the highest EBS. However, an apical section of Group 1 samples (2.81±0.11MPa) displayed the lowest outcome of bond integrity. Intergroup comparison analysis revealed that Group 4 (PIPS+17% EDTA) and Group 2 (CP+17% EDTA) samples demonstrated comparable values of bond integrity and bacterial survival. Canal disinfection using the synchronized microbubble photodynamic activation (SYMPA) technique proved to be a promising alternative technique in decreasing the count of E. faecalis and improving extrusion bond strength of gutta percha to canal dentin.

Probiotic-fermented tomato with hepatic lipid metabolism modulation effects: analysis of physicochemical properties, bioactivities, and potential bioactive compounds.

Lactiplantibacillus plantarum NCUH001046 (LP)-fermented tomatoes exhibited the potential to alleviate obesity in our previous study. This subsequent study further delves deeper into the effects of LP fermentation on the physicochemical properties, bioactivities, and hepatic lipid metabolism modulation of tomatoes, as well as the analysis of potential bioactive compounds exerting obesity-alleviating effects. Results showed that after LP fermentation, viable bacterial counts peaked at 9.11 log CFU mL-1 and sugar decreased, while organic acids, umami amino acids, total phenols, and total flavonoids increased. LP fermentation also improved the inhibition capacities of three digestive enzyme activities and Enterobacter cloacae growth, as well as antioxidant activities. Western blot results indicated that fermented tomatoes, especially live probiotic-fermented tomatoes (LFT), showed improved effects compared to unfermented tomatoes in reducing hepatic lipid accumulation by activating the AMPK signal pathway. UHPLC-Q-TOF/MS-based untargeted metabolomics analysis showed that chlorogenic acid, capsiate, tiliroside, irisflorentin, and homoeriodictyol levels increased after fermentation. Subsequent cell culture assays demonstrated that irisflorentin and homoeriodictyol reduced lipid accumulation via enhancing AMPK expression in oleic acid-induced hyperlipidemic HepG2 cells. Furthermore, Spearman's correlation analysis indicated that the five phenols were positively associated with hepatic AMPK pathway activation. Consequently, it could be inferred that the five phenols may be potential bioactive compounds in LFT to alleviate obesity and lipid metabolism disorders. In summary, these findings underscored the transformative potential of LP fermentation in enhancing the bioactive profile of tomatoes and augmenting its capacity to alleviate obesity and lipid metabolism disorders. This study furnished theoretical underpinnings for the functional investigation of probiotic-fermented plant-based foods.

Microbiological indices of unregulated herbal drinks in Benin City, Nigeria: A potential health hazard to consumers

Abstract Background: The use of herbal medicine has increased globally due to people’s dissatisfaction with conventional medicine, family traditions, poverty, and prior positive experiences. Since the last decade, the general public has become increasingly interested in herbal products from several medicinal plants. This study sought to evaluate the microbial contamination of liquid herbal drinks sold in Benin City, Nigeria. Materials and Methods: Fifty different herbal medicines were purchased from three different locations in the study area. The 50 herbal medicines were centrifuged and the sediment was used for culture, biochemical, and antibiotic tests for the identification of isolated microorganisms and the assessment of the total viable bacterial count. Results: In comparison to regulated herbal preparations (4%), a percentage (36%) of unregulated herbal preparations contained viable bacteria. The most common bacterium found in unlicensed herbal medicines was Klebsiella pneumonia (10%). The percentage of regulated and unregulated herbal preparations that had microbiological contamination that was above the permissible limit (&gt;10 colony-forming unit/ml) was 2% and 26%, respectively. Conclusions: Numerous unlicensed herbal treatments in Benin City have microbial contamination over the World Health Organization-permitted limit for aerobic and coliform bacteria. The regulatory bodies should step up their efforts to make sure that all herbal medicines marketed in the nation are legally registered and created in compliance with current Good Manufacturing Practice standards.

Technological quality and fungal community of Kombucha fermented with hemp leaves and milky mushroom flour (Calocybe indica).

Kombucha is traditionally a non-alcoholic beverage whose production is dependent on culture and the various ingredients used as substrates for fermentation. The goal of our study was to apply hemp leaf and milky mushroom (Calocybe indica) flour as functional ingredients to enhance phytonutrient quality, along with using a microbial consortium highly symbiotic with these ingredients. The study determined the content of phytonutrients (phenolic and flavonoids content), antioxidant activity through percentage inhibition of DPPH radical scavenging activity (%), and microbial communities changes during fermentation. The microbial changes were evaluated by cell viable count (total bacteria, Lactic Acid Bacteria, and Yeast & Mold) and ITS in prepared kombucha (using red tea leaves, pandan leaves, and sucrose) supplemented with functional ingredients: T1 (hemp leaves (control)) and T2 (hemp leaves with milky mushroom flour). The results indicated that microbial consortium changed during fermentation. In the first 7 days, the levels of yeast and mold increased to 6.17 and 6.18 log CFU/mL, respectively. By day 21, the levels of both T1 and T2 continued to rise, reaching 7.78 and 7.82 log CFU/mL, respectively. The viable count of lactic acid bacteria in T1 and T2 gradually increased to 6.79 and 6.70 log CFU/mL, respectively, by day 14. These changes resulted in a marked decrease in pH value, reaching 3.63 and 3.23 in T1 and T2, respectively, by the end of the process (21 days). The total bacterial viable count decreased with an increase in the fermentation time. During fermentation, unique genera of tea fungus observed in T1 and T2 were 64% and 19%, respectively. At the beginning (0 days), the top five genera found in T1 were: g__Setophoma (25.91%), g__Macrocybe (14.88%), g__Cladosporium (7.81%), g__Phaeosphaeria (7.12%), g__Malassezia (6.63%), while the top five genera in T2 were g__Macrocybe (94.55%), g__Setophoma (1.87%), g__Cladosporium (0.77%), g__Phaeosphaeria (0.40%), g__Cordyceps (0.38%). However, on day 21 (end of the process), it was found that g__Dekkera had the highest relative abundance in both T1 and T2. In addition, the supplementation of the two ingredients affected the total phenolic and total flavonoid content of the treatments. At the end of the process, T2 showed values of 155.91 mg GAE/mL for total phenolics and 1.01 mg CE/mL for total flavonoids, compared to T1, which had 129.52 mg GAE/mL and 0.69 mg CE/mL, respectively. Additionally, the DPPH inhibition was higher in T1 (91.95%) compared to T2 (91.03%). The findings suggest that kombucha fermented with these innovative ingredients exhibited enhanced phytonutrients, and served as substrate for LAB and tea fungus fermentation, while limiting the growth of fungal genera and diversity of microbial consortium.

Isolation and identification of bacteria from engine oil polluted soil from mechanic workshops in Okija Town

This research was conducted for the isolation and identification of bacteria from engine oil polluted soil from mechanic workshops in Okija village. Two different mechanic workshops within Okija were selected and soil samples were collected differently based on top soil and depth soil from each site. Then 0.1ml was taken from the dilution 10-3 to 10-6 diluents and inoculated into a Bushnell Haas agar (containing: (g/l) 0.2, MgSO4; 0.02, CaCl2; 1.0, KH2PO4; 1.0, K2HPO4; 1.0, NH4NO3; 0.05, FeCl3; 20.0, Agar and 5ml of fresh engine oil as sole carbon source) and was incubated at 370C for 5 -7 days. Spread plate method involving the use of serial dilutions was employed for the isolation of bacteria. The culture was examined for bacterial growth and subsequently cultured the specific bacteria growth on nutrient agar plates with 2ml of fresh engine oil for 24 hours to determine engine oil degradability by the isolated bacteria. The numbers of viable bacterial count were 20, 26, 18 and 28 as expressed in colony forming units per milliliter (cfu/ml). The bacterial count was furthermore expressed in percentage per the dilution factor 10-3; S1Top, S1Depth, S2Top and S2Depth were 21.74%, 28.26%, 19.56% and 30.44% respectively. The bacteria species isolated were Serratia, Micrococcus, Pseudomonas and Bacillus species. Bacillus was the most dominant. There was presence and activity of bacteria species in the depth soil than top soil. The bacterial species isolated were able to degrade fresh engine oil especially Bacillus species. From, the data obtained it was found that depth soil has more presence and activity of bacterial species because there is less disturbance in the depth soil than top soil. Bacillus species and Pseudomonas species are most adapted to conditions present in soils polluted with used engine oil and hence could be exploited in bioremediation activities in cases of accidental oil spillage.

Comparison of the agar contact method and the wet-dry double swabbing method for determining the total viable bacterial count on pig carcass surfaces

A practical and representative sampling method for microbiological examination of the slaughter process is useful for identifying abattoir-specific risk factors within the pig slaughter line. The aim of this study was to examine the suitability of an agar contact method (ACM), where the agar was homogenized before the microbiological processing, in comparison with the wet-dry double swabbing method (WDSM) for quantitative determination of total viable counts (TVC) on pig skin surfaces. In our experimental trial, pig skin pieces were artificially contaminated at 2 levels (3 log and 7 log cfu/ml) with a suspension of bacteria species commonly found on pig skin and cultivated in vitro. Within our field trial, pig carcasses were investigated at pre-chilling in an abattoir under standard processing conditions. For both sampling methods, TVC was determined, and statistical equivalence tests were calculated. Linear regression models showed the similarity of the sampling methods, with coefficient of determination (R2) > 90% and slope parameters of nearly 1 for both trials separately. Statistically significant equivalence between the 2 sampling methods was proven in both trials (with p < 0.0001 within an equivalence range of ± 0.5 log cfu/ml, respectively). The field trial revealed TVC on carcass surfaces sometimes at or below the lower detection limit for the ACM, while TVC from all carcasses were able to be determined by WDSM. Overall, low contamination levels were less reliably detectable by ACM than by WDSM. The ACM can be seen as an additional and suitable sampling procedure for pig skin and can contribute to the identification of abattoir specific risk factors for investigations of the hygienic status at process stages along the pig slaughter line.

English

The degradation capacity of Xanthomonas campestris on crude oil, petrol, diesel and kerosene and the effect of monoammonium phosphate (MAP) addition on biodegradation efficiency were investigated in this study. X. campestris was identified using 16S rRNA sequencing while the concentration of the test compounds was determined via gas chromatography. Higher cell densities and viable bacterial counts were obtained in the presence of MAP. No significant differences (p≤0.05) were seen in counts between the two MAP application concentrations of 150 mg L-1 and 250 mg L-1. Statistically significant differences (p≤0.05) were, however, observed between the set-ups with MAP added and those without. At the end of the study, it was ascertained that addition of MAP improved the efficiency of biodegradation by up to 5.86% – 14.44% at 150 mg L-1 MAP application level and 11.11% – 15.83% at 250 mg L-1 MAP concentration. The greatest increase was seen with petrol (14.2% – 15.8%) which was also the most readily degraded of the test compounds. Biodegradation half-lives were also improved by up to 8.8 days on average in the presence of MAP. Fractions C26 – C30 proved to be the most recalcitrant based on mean removal percentages. The findings suggest that X. campestris was able to effectively breakdown the test hydrocarbon complexes and the addition of MAP enhanced its biodegradation efficiency. The bacterium may, therefore, be applied to bioremediation of environmental media polluted by crude oil or its derivative hydrocarbon fuels.

Evaluation of the physicochemical properties and bacterial loads of selected rivers in Ondo State, Nigeria.

Water is crucial to human existence but may be contaminated with microorganisms, thus making it unfit for consumption. This study aimed to evaluate the physicochemical properties and bacterial loads of selected river waters in Ondo State, Nigeria. Ten major rivers were sampled between April and August, 2021. The pH, temperature, total alkalinity, colour, turbidity, electrical conductivity, dissolved oxygen, ammonium, aluminium, organic matters, nitrate levels including the microbial loads were determined according to standard procedures. Confirmation of identified isolates was achieved by API 20E and API 20NE. The turbidity, colour, conductivity, ammonium, and aluminium ranged from 4.3 to 15.2 NTU, 4 to 20 NTU, 123.5 to 580.2 mgL-1, 0 to 3.5 mgL-1, and 0.05 to 1.7, respectively. Most physicochemical parameters showed no significant differences from the WHO permissible limits for drinking water (p > 0.05). The total viable bacterial count in the rivers ranged from 1.5 × 105 to 6.3 × 105 CFUmL-1, while the total coliform count ranged from 1.3 × 103 to 4.8 × 103 CFUmL-1. The predominant bacteria were Escherichia coli and Pseudomonas aeruginosa. This study revealed that the physiochemical properties of the waters were majorly within the WHO permissible standards but with significantly higher bacterial loads.

Multidrug-Resistant Enteric Bacteria in the Water Sources of Kalgo Metropolis, Nigeria

The high incidence of diseases, such as diarrhoea, typhoid fever, cholera, and bacillary dysentery among the populace, especially in remote and developing areas, has been traced to the domestic use of contaminated water. This study aimed to isolate enteric bacteria in major drinking water sources situated within the Kalgo metropolis, Nigeria. Three water samples were aseptically collected in triplicates from three different areas of the city. After serial dilution, the samples were inoculated on nutrient agar and each sample's total viable bacterial count was taken. The enteric bacteria were isolated and identified using standard protocols. The isolates were subjected to antibiotic sensitivity test using the Kirby Bauer disk diffusion method. The inhibition zones were measured in millimeters(mm). Seven (7) different species of bacteria were isolated from the collected water samples.The isolated organisms included Shigella spp., Serratia spp., Klebsiella spp., Escherichia coli, Proteus spp., Yersinia spp., and Salmonella spp. Among these bacterial isolates, E. coli and Salmonella spp.were found to have the highest frequency of 29.63% and 25.93%, respectively. While, Serratia spp.had the lowest frequency of 3.9%. The sensitivity profile showed that E. coli, Salmonella spp.,Klebsiella spp., Shigella spp., and Serratia spp. were resistant to ampicillin. In contrast, Proteus spp. and Yersinia spp. showed high and intermediate susceptibility, respectively.The presence of multidrug-resistant enteric bacteria in water samples suggests the need to improve water quality through its assessment and treatment before use.

Comparative evaluation of disinfectant efficacy against biofilm-residing microorganisms

Introduction. Bacteria in biofilms (BFs) have increased resistance to antibacterial agents, including disinfectants; however, the efficacy level varies depending on the chosen treatment. Therefore, evaluation of efficacy of main disinfectants against BF-residing microorganisms is of scientific and practical interest.&#x0D; The purpose of the study was to explore the effect of disinfectants from various chemical groups on gram-positive and gram-negative bacteria residing in BFs.&#x0D; Materials and methods. The effect of the following disinfectants has been evaluated: alkyldimethylbenzylammonium chloride (ADBAC), tertiary amine (TA), polyhexamethylene guanidine chloride (PHMG), hydrogen peroxide (HP), chloramine (CA), dichloroisocyanuric acid sodium salt (Na DCC), sodium hypochlorite (HC), ethyl alcohol (EA), glutaraldehyde (GA)) against Pseudomonas aeruginosa ATCC 15442 and Staphylococcus aureus ATCC 6538-P BFs. BFs were grown in 96-well plates at 37ºC for 24 hours and then exposed to biocide solutions. The efficacy of disinfectants was evaluated by the number of remaining viable cells and BF relative density.&#x0D; Results. The analyzed bacterial strains formed moderate BFs; the average number of viable cells in BFs was 6.51 ± 0.19 lg. The viable bacterial cell counts in BFs reduced by more than 4 lg when exposed to HP solutions at a concentration of 6%, Na DCC solution — 0.1% (by active chlorine), HC — 1% (by active chlorine), CA – 1% (by product), PHMG — 0.05%, TA — 1.0 %. The BF density decreased by more than 70%. ADBAC solutions at concentrations of 0.1–1.0%, TA — 0.05%, HP — 3%, Na DCC solution — 0.05% (by active chlorine) caused a 2-lg reduction in viable cell counts in BFs. The efficacy of chlorine-active compounds and HP increased when 0.5% sulfonol was added. GA (0.25–1.00%) and EA (40–70%) solutions were ineffective against BF microorganisms.&#x0D; Conclusion. A promising potential in combating microbial biofilms is demonstrated by disinfectants from the group of oxidizing agents (chlorine-active and oxygen-containing), TA and PHMG; using ADBAC as an individual compound is ineffective; aldehydes and alcohols are unable to destroy BFs and eliminate microorganisms in them.

Antibacterial Effect of Three Kinds of Methylene Blue Photosensitizers Mediated Photodynamic Therapy on Streptococcus Mutans

In order to study the antibacterial effect of methylene blue (MB) photosensitizer-mediated photodynamic therapy (PDT) on Streptococcus mutans in aqueous solvent form, SDS solution form and their mixed form, the influence of MB-PDT on antibacterial effect of Streptococcus mutans in different dosage forms was analyzed. The number of colonies after and before photodynamic therapy mediated by MB-mediated photodynamic therapy was compared by in vitro viable bacterial colony counting method. Negative control group, light alone group, water dosage MB group, mixed dosage MB group, SDS dosage MB group, water dosage MB-PDT group, mixed dosage MB-PDT group and SDS dosage MB-PDT group were set up respectively the effect of different dosage forms of photosensitizers on the antibacterial effect of Streptococcus mutans was analyzed by counting and comparing in vitro for 24 hours. Through in vitro culture experiment, it was found that the number of colonies in water dosage form, mixed dosage form and SDS dosage form MB-PDT group was less than that in water dosage form, mixed dosage form and SDS dosage form MB. The proportion of viable bacteria in SDS MB group was significantly lower than that in water and mixed MB groups, and the antibacterial rate of SDS MB-PDT group was significantly higher than that in water and mixed MB-PDT group. These results indicated that MB-PDT could significantly inhibit the proliferation and growth of Streptococcus mutans. Among them, SDS MB-PDT group had more obvious antibacterial effect on Streptococcus mutans than water MB-PDT group and mixed MB-PDT group, but there was no significant difference in antibacterial effect between water MB-mediated PDT group and mixed MB-mediated PDT group.

Systemic validation of mono-herbal Siddha formulation Kanduparangi chooranam through ICP-OES, GC-MS and microbial contamination analysis

Introduction: Standardization of the Siddha drugs is the process that enhances the quality of the drug before entering into industrial purposes in pharmacological and pharmaceutical sciences. The reports from the instrumental analysis give adequate details to claim the therapeutic efficacy of the drugs without any hazardous effects which are already quoted in the Siddha classical textbooks. Materials and methods: The drug Kanduparangi chooranam was analyzed by the following methods, Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), total and specific microbial contamination test and Gas Chromatography-Mass Spectroscopy (GC-MS). Results and discussion: ICP-OES results of Kanduparangi chooranam showed that the toxic heavy metals like As, Cd, Hg and Pb were Below Detection Limit (BDL). The total viable aerobic bacterial count and total viable fungal count of Kanduparangi chooranam showed that 9.2x 102 and 12.3 x 102 respectively detected level contamination were under the limits value of safety as per WHO guidelines. Specific microbial contamination test of Kanduparangi chooranam showed that there was no growth of the following microorganisms, Salmonella species, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. GC-MS analysis revealed that there was no trace of chemical compounds of Organo-pesticide residues (Chlorine, Phophorus &amp; Pyrithroids) and Aflatoxins B1, B2, G1 and G2. Conclusion: Kanduparangi chooranam which was prepared from purified roots of Pygmaeopremna herbacea in a proper way as per the Siddha classical method, is useful for treatment purposes devoid of toxic heavy metals, microbes, pesticides and aflatoxins.

The Effects of UV-C Irradiation and Low Temperature Treatment on Microbial Growth and Oxidative Damage in Fresh-Cut Bitter Gourd (Momordica charantia L.)

Fresh-cut fruits and vegetables are convenient and retain maximum nutrients. However, even minimal processing accelerates product deterioration and reduces food safety due to microbial infection. In this study, the effects of UV-C irradiation, low temperature treatment, and their combination on the microbial risk of fresh-cut bitter gourd were evaluated. Firstly, next-generation sequencing technology was utilized to identify microorganisms on the surface of fresh-cut bitter gourd after 12 h of exposure to room temperature, and a total of 34 bacterial species were identified. Subsequently, fresh-cut bitter gourd treated with UV-C or/and 4 °C and then kept at room temperature for 6 h was assessed for its viable bacterial count. The results showed that both 0.5 and 1.5 kJ·m−2 UV-C irradiation significantly inhibited microbial growth compared to 4 °C and the no treatment control. Meanwhile, no significant differences were observed between UV-C and the combined treatments. Lower doses of UV-C irradiation reduced hydrogen peroxide and malondialdehyde content, increased the proline level, and improved the activities of antioxidant enzymes such as superoxide dismutase, ascorbate peroxidase, catalase, and critical enzymes involved in the phenylpropanoid pathway, such as phenylalanine ammonia-lyase and polyphenol oxidase. This suggests that UV-C irradiation alone can effectively reduce bacterial contamination in fresh-cut bitter gourd to an acceptable level.

In Vitro Biofilm Formation on Zirconia Implant Surfaces Treated with Femtosecond and Nanosecond Lasers.

(1) Background: The purpose of this study was to evaluate how a zirconia implant surface treated with laser technology affects the degree of biofilm formation. (2) Methods: Experimental titanium (Ti) disks were produced that were sandblasted with large grit and acid-etched (T), and they were compared with zirconia (ZrO2) discs with a machined (M) surface topography; a hydrophilic surface topography with a femtosecond laser (HF); and a hydrophobic surface topography with a nanosecond laser (HN) (N = 12 per surface group). An in vitro three-species biofilm sample (Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi)) was applied to each disc type, and bacterial adhesion was assessed after 48 and 72 h of incubation using an anaerobic flow chamber model. Statistical significance was determined using the Kruskal-Wallis H test, with Bonferroni correction used for the post-hoc test (α = 0.05). (3) Results: Compared to the T group, the M group exhibited more than twice as many viable bacterial counts in the three-species biofilm samples (p < 0.05). In comparison to the T group, the HF group had significantly higher viable bacterial counts in certain biofilm samples at 48 h (Aa and Pi) and 72 h (Pi) (p < 0.05). The HN group had higher viable bacterial counts in Pi at 48 h (5400 CFU/mL, p < 0.05) than the T group (4500 CFU/mL), while showing significantly lower viable bacterial counts in Pg at both 48 (3010 CFU/mL) and 72 h (3190 CFU/mL) (p < 0.05). (4) Conclusions: The surface treatment method for zirconia discs greatly influences biofilm formation. Notably, hydrophobic surface treatment using a nanosecond laser was particularly effective at inhibiting Pg growth.

Identification of dominant spoilage bacteria, bacterial diversity analysis, and antibacterial exploration of chilled monkfish

In this study, we aimed to investigate spoilage bacteria in monkfish stored under vacuum and aerobic (air) refrigeration at 4 °C for the first time. In vitro bacterial cultures, coupled with Sanger sequencing of genes, were used to isolate and identify 21 and 31 bacterial strains from vacuum-packed and aerobically packed monkfish, respectively. The isolated strains were back-inoculated into sterile fish blocks and inactivated fish juice. Our findings revealed that Carnobacterium, Shewanella, Vagococcus, Myroides, and Psychrobacter increased the production of total volatile base nitrogen (TVB-N) and trimethylamine (TMA) from monkfish. Monkfish showed a decrease in bacterial flora diversity with storage time, the emergence of dominant species during the spoilage process, and differences in bacterial growth tolerance in different packaging forms, resulting in variability in bacterial community structure. Shewanella accelerated the spoilage of monkfish in both packaging forms. Vagococcus and Psychrobacter were numerically dominant in both storage forms. Unlike some spoilage bacteria in refrigerated fish, Carnobacterium (11.72%) and Myroides (9.01%) were the specific spoilage bacteria in vacuum and aerobic storage at 4 °C, respectively. Furthermore, a combination of nisin (NS), ε-polylysine (ε-PL), and citric acid (CA) significantly reduced the survival rate of dominant spoilage bacteria and the total viable bacterial count in monkfish.

Viability of Anaerobic Bacteria in Dental Sub-Gingival Calculus and Its Minerlization – An Observational Microbiological Study

Background: Dental calculus, a mineralized product of plaque, remains ignored and is considered as a fossilized remnant of minor significance. Dental plaque is still considered as the main culprit in etiopathogenesis of periodontal disease. Several studies suggest that calculus has a porous and spongy nature because of which it may act as a reservoir for endotoxins and bacterial antibodies. However, the viability of bacteria in sub gingival calculus and its role in the pathogenesis and disease progression still remains a mystery. The present study aims to investigate the viability of bacteria within sub-gingival calculus and to assess the degree of mineralization of dental calculus and the variation of viable micro flora corresponding to the extent of mineralization. Materials and Methods: Eighteen samples of sub gingival calculus were harvested from patients with chronic inflammatory periodontal disease. The samples were divided into two groups, Group 1 (non-irradiated) and Group 2 (samples exposed to UV radiation) and Group 3 (samples assessed for mineralization). Group 1 and 2 samples were utilized for anaerobic culture to detect the presence of anaerobic bacteria. Group 3 samples were crushed in a Universal testing machine and mineralization was assessed according to the force required for crushing. Results: All study specimens showed positive bacterial growth under anaerobic conditions. The bacterial cultures revealed decrease in the bacterial count in Group 2 i.e. Irradiated group (I) when compared with Group 1 i.e. Non-irradiated group (NI). The results obtained from computerized Universal Testing Machine showcased varying values required to crush the sub-gingival calculus samples suggesting variation in mineralization of each sample. The correlation between mineralization and viable anaerobic bacterial count revealed an inverse relation. Conclusion: Sub-gingival calculus plays a key role in harbouring pathogenic anaerobic bacteria, owing to its porous ....