The effect of thyme essential oil and endothelial progenitor stem cells on lipopolysaccharide-induced sepsis in C57BL/6 mice.

Sepsis is a potentially fatal syndrome related to severe systemic inflammation developed by infection. Despite different antimicrobial therapies, morbidity and mortality rates remain high. Herbs along with cell therapy have been introduced as a promising option to improve the symptoms of sepsis. The present study aimed to evaluate the therapeutic effect of simultaneous administration of thyme essential oil (TEO) and endothelial progenitor stem cells (EPCs) on lipopolysaccharide (LPS)-induced sepsis in C57BL/6 mice. Sepsis was induced in C57Bl/6J mice by intraperitoneal injection of LPS, followed 2 h later by an intravenous injection of EPCs or oral administration of TEO or simultaneous administration of TEO and EPCs. After 10 days, the complete blood cell, renal and liver factors, serum levels of inflammatory cytokines, and angiogenic factors were measured. Simultaneous treatment with EPCs and TEO significantly increased the survival of mice with sepsis and modulated the inflammatory response by reducing the serum levels of pro-inflammatory cytokines. Moreover, this treatment significantly reduced the level of white blood cells and neutrophils and increased the number of red blood cells, the percentage of hematocrit, and hemoglobin. The combination of TEO with EPCs decreased organ injuries and was assessed by lower levels of the liver enzymes alanine aminotransferase and aspartate aminotransferase compared to the sepsis group. Administration of EPCs and TEO also significantly improved angiogenic factors, lung function, and toll-like receptor 4 expression. EPCs in combination with TEO increase survival in the LPS-induced sepsis mice model by acting on several targets. Thus, the combination of TEO with EPCs can be a feasible approach for the future clinical treatment and control of sepsis.

Transcriptional alteration of genes linked to gastritis concerning Helicobacter pylori infection status and its virulence factors.

BACKGROUND: Helicobacter pylori infection and heterogeneity in its pathogenesis could describe diversity in the expression of inflammatory genes in the gastric tissue. We aimed to investigate transcriptional alteration of genes linked to gastritis concerning the H. pylori infection status and its virulence factors. METHODS AND RESULTS: Biopsy samples of 12 infected and 12 non-infected patients with H. pylori that showed moderate chronic gastritis were selected for transcriptional analysis. Genotyping of H. pylori strains was done using PCR and relative expression of inflammatory genes was compared between the infected and non-infected patients using relative quantitative real-time PCR. Positive correlations between transcriptional changes of IL8 with TNF-α and Noxo1 in the infected and TNF-α with Noxo1, MMP7, and Atp4A in the non-infected patients were detected. Six distinct genotypes of H. pylori were detected that showed no correlation with gender, ethnicity, age, endoscopic findings, and transcriptional levels of host genes. Irrespective of the characterized genotypes, our results showed overexpression of TNF-α, MMP7, Noxo1, and ATP4A in the infected and IL-8, Noxo1, and ATP4A in the non-infected patients. CONCLUSIONS: A complexity in transcription of genes respective to the characterized H. pylori genotypes in the infected patients was detected in our study. The observed difference in co-regulation of genes linked to gastritis in the infected and non-infected patients proposed involvement of different regulatory pathways in the inflammation of the gastric tissue in the studied groups.

Interaction of human oral cancer and the expression of virulence genes of dental pathogenic bacteria.

Oral squamous cell carcinoma (OSCC) are one of the major causes of cancer morbidity and mortality worldwide. Dental microbiome has been considered as inducing agents in oral carcinogenesis. Therefore, the objective of this study was to investigate the interaction of the gene expression of the dental microbiome and OSCC patients. A cross-sectional study was designed by recruiting confirmed OSCC patients attending the University hospital during October 2018 and July 2019. The dental bacteria were isolated and confirmed by PCR technique. The expression of host and bacterial virulence genes was determined using qPCR. This study shows that 54% of T. forsythia found to be the most predominant organisms in 30 positive cases, followed by 34% of Campylobacter rectus and 29% of Prevotella intermedia. The expression of mRNA levels of bspA, csxA, fadA and interpain A in the OSCC- bacteria positive cases was significantly higher than the control group (P < 0.001). It was further found that interpainA, csxA, fadA, and bspA genes have the potential effects on the cellular gene expression in OSCC patients. A significant correlation was seen between expression patterns of CXCL10, DIAPH1, NCLN and MMP9 genes with interpain A, fadA, and bspA involved in OSCC cases The results indicate that the species specific bacteria may play a role in triggering chronic inflammation in OSCC patients. Therefore, alteration in the gene expression through the dental microbiome could be used as an alternative target in the clinical practice to detect OSCC.

Preparation and optimization of ciprofloxacin encapsulated niosomes: A new approach for enhanced antibacterial activity, biofilm inhibition and reduced antibiotic resistance in ciprofloxacin-resistant methicillin-resistance Staphylococcus aureus.

Ciprofloxacin is an alternative to vancomycin for treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. The objective of this study was to optimization of niosomes encapsulated ciprofloxacin and evaluate their antibacterial and anti-biofilm efficacies against ciprofloxacin-resistant methicillin-resistant S. aureus (CR-MRSA) strains. Formulation of niosomes encapsulated ciprofloxacin were optimized by changing the proportions of Tween 60, Span 60, and cholesterol. The optimized ciprofloxacin encapsulated niosomal formulations based on Span 60 and Tween 60 were prepared and characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The SEM and TEM results showed that the formulation of niosomes encapsulated ciprofloxacin were spherical with a size between 50 and 150 nm. The prepared niosomal formulations showed high storage stability up to 30 days with the slight change in size and drug entrapment during the storage, making them good candidates for drug delivery systems. Optimum niosome encapsulated ciprofloxacin enhanced antibacterial activity against CR-MRSA strains via reduction in minimum inhibitory concentration (MIC) value and inhibited significantly biofilm formation. Niosome encapsulated ciprofloxacin down-regulated the expression of icaB biofilm formation gene. Our results showed that encapsulating ciprofloxacin in niosomes is a promising approach to enhanced antibacterial activity, biofilm inhibition and reduced resistance to antibiotic in CR-MRSA strains.

Antimicrobial Efficacy of Saline, Chlorhexidine, and Zataria Multiflora and Mentha Piperita Essential Oils in Root Canal Irrigation of Primary Molars.

Objectives: This study aimed to compare the antimicrobial efficacy of saline, 0.5% and 2% Zataria multiflora (Z. multiflora) essential oil, 0.5% and 2% Mentha piperita (M. piperita) essential oil, and 0.2% chlorhexidine (CHX) as root canal irrigants for primary molar teeth. Materials and Methods: A total of 64 primary molars were used in this in vitro study. The teeth were randomly assigned to six groups (N=10). The root canals were prepared up to file #35, and all teeth were sterilized before contamination with Enterococcus faecalis (E. faecalis; ATCC 29212) suspension. After 48 hours of incubation, the root canals in each group were irrigated with the respective irrigants. Sterile paper points were then used to collect microbial samples from the root canals. A colony counter was used to count the number of colony-forming units (CFUs). Data were analyzed by SPSS version 20 (alpha=0.05). Results: The colony count was significantly different among the groups (P<0.001), and 2% M. piperita (P=0.009), 0.5% Z. multiflora (P=0.021), and 0.2% CHX (P=0.002) were significantly more effective than saline in elimination of E. faecalis. The ascending order of microbial count after irrigation was as follows: saline > 0.5% M. piperita > 0.2% CHX > 2% M. piperita > 0.5% Z. multiflora. Conclusion: The current study showed the optimal antibacterial activity of 0.5% Z. multiflora essential oil and 2% M. piperita essential oil against E. faecalis, and indicated their possible efficacy for use as an irrigant for root canal irrigation of primary molars.

Preparation of UiO-66 loaded Letrozole nano-drug delivery system: enhanced anticancer and apoptosis activity.

The use of drug delivery systems in targeting and achieving the targeting of drugs in treating diseases, especially cancer, has attracted the attention of researchers. Letrozole is one of the drugs for the treatment of breast cancer. In this study, the organic-metallic pharmaceutical porous nanostructure based on zirconium UiO-66 loaded letrozole was synthesized. Its cytotoxicity and effect on apoptosis and migration against breast cancer cell line were investigated. In this experimental study, the UiO-66 nanoparticle-loaded letrozole was synthesized using zirconium chloride (ZrCl4), dimethylformamide (DMF), and HCl. Its characteristics were determined by scanning electron microscopy, and its average size was determined by the DLS method. Also, the rate of letrozole drug release from the nanoparticle was investigated in 24, 48, and 72 h. In addition, its cytotoxicity effects were investigated using the MTT colorimetric method at concentrations of 3.125-100 µg/ml against the breast cancer cell line (MCF-7) in the periods of 48 and 72 h. Also, the expression level of apoptotic genes Bax and Bcl2 was investigated by the Real-Time PCR method. Also, the amount of cell migration was done by the migration assay method. The results showed that UiO-66 bound to letrozole had a spherical morphology and an average size of 9.2 ± 160.1. Also, the letrozole drug was loaded by 62.21 ± 1.80% in UiO-66 nanoparticles and had a slower release pattern than free letrozole in the drug release test, so within 72 h, 99.99% of free letrozole was released in If in UiO-66 containing letrozole, 57.55% of the drug has been released. Also, the cytotoxicity results showed that UiO-66 bound to letrozole has more significant cytotoxic effects than free letrozole (p < 0.05). Also, the results of Bax and Bcl2 gene expression showed that the treatment of MCF-7 cells with UiO-66 nanoparticles attached to letrozole increased the expression of Bax and Bcl2 genes compared to the reference gene Beta-actin in MCF-7 cell line, respectively. (p < 0.05) increased by 3.71 ± 0.42 and (p < 0.01) decreased by 0.636 ± 0.034 (p < 0.05). Cell migration results showed that the concentration of 50 µg/ml of UiO-66 bound to letrozole decreased the migration of MCF-7 cells. Generally, the results of this study showed that UiO-66 loaded letrozole can be used as a suitable drug carrier for cellular purposes, as it has increased the effects of cytotoxicity and the rate of apoptosis in breast cancer cell line (MCF-7), so it can be used with more studies used nanocarriers as a drug delivery system.

Early detection of oral bacteria causing gum infections and dental caries in children.

Background and Objectives: Periodontal diseases are resulted from gum infections and dental plaques, which are mainly caused by the bacterial agents. Since dental monitoring includes important prognostic roles, the aim of this study was to detect the most common periodontal pathogenic bacteria in children. Materials and Methods: A total of 200 clinical samples were collected from dental plaques and gingival grooves. Target-specific primers were designed for hbpA in Aggregatibacter actinomycetemcomitans, fimA in Porphyromonas gingivalis and 16S rRNA in Prevotella intermedia, Tannerella forsythia and Treponema denticola. Then, a multiplex polymerase chain reaction method was optimized for the highlighted bacterial agents. Results: In general, the highest and the lowest bacterial prevalence rates belonged to Tannerella forsythia (88%) and Porphyromonas gingivalis (13%), respectively. Furthermore, prevalence rates of Aggregatibacter actinomycetemcomitans, Prevotella intermedia and Treponema denticola were 25, 21 and 45% in samples, respectively. Conclusion: There were significant associations between dental/oral health and microbial community. Metabolism of the oral bacteria, including biofilm formation, can affect gums and develop dental plaques and hence dental caries, especially in children. Early diagnosis of dental caries in children via rapid, accurate molecular methods can increase the diagnostic capacity in clinical cases and therefore prevent periodontal infections in adulthood.

Effects of Dental Pulp Stem Cell Preconditioning on Osteogenesis using Conditioned Media of Probiotics Bacteria.

Background: Stem cells are used to treat numerous diseases; however, their lifespan is rather short. Factors such as probiotics affect and improve various cell lineage efficacies. The aim of this study was to investigate the effects of probiotics-conditioned media on dental pulp stem cell potentials in osteogenesis. Methods: The experiment was initiated by culturing Lactobacillus casei and Lactobacillus acidophilus probiotics as well as DPS-7 cells. Bacterial supernatants were separated and concentrated as the conditioned media. The DPS-7 cells were treated with various concentrations of the conditioned media. Furthermore, MTT assay and alkaline phosphatase activity were used. The mRNA expression of three genes (bFGF, EGF-ß and BMP-2) involved in osteogenesis was analyzed using a real-time polymerase chain reaction. Results: The response of dental pulp stem cells to probiotics preconditioning promoted cell proliferation, increased alkaline phosphatase activity and upregulated bFGF and BMP-2 gene expression. Increased expression was significant for BMP-2 and moderate for bFGF; however, it was non-significant for EGF-ß. The use of the two probiotics was the most effective. Conclusion: In general, synergism of the combined probiotics preconditioning induces differentiation of DPS-7 cells into osteoblasts most effectively.

Transcriptional analysis of Helicobacter pylori cytotoxic-associated gene-pathogenicity island in response to different pH levels and proton pump inhibitor exposure.

BACKGROUND: Long-term use of proton pump inhibitors (PPIs) can increase the risk of gastric cancer in Helicobacter pylori-infected patients; nevertheless, there is no data about their impact on the pathogenicity of H. pylori. This study aimed at investigating the transcriptional alteration of key gene mediators of cytotoxin-associated gene-pathogenicity island (cag-PAI) among clinical H. pylori isolates in response to omeprazole at different pH levels. METHODS: Accordingly, H. pylori isolates with the same virulence genotypes selected from the gastric biopsies of patients and transcriptional alteration in the cag-PAI genes studied in the presence or absence of omeprazole (2 mg/mL) at pH 2.0, 4.0 and 7.0 after 30 and 90 minutes of the treatment. Relative changes in the transcriptional levels were recorded in each assay, separately. RESULTS: Of 18 H. pylori isolates, the cag-PAI empty site was detected in four strains, while the presence of cagA, cagL and cagY was characterized in 77.7%, 83.3% and 83.3% of the cag-PAI-positive strains, respectively. Transcriptional analysis of the selected strains showed up-regulation of cagA and cagL, mainly at pH 2.0 and 4.0 after 30 and 90-minute exposure. A diversity in the expression levels of cag-PAI genes was seen among the strains at the extent and time of induction. CONCLUSION: Our results showed that omeprazole could increase the expression of H. pylori cagA and cagL at acidic pH. Heterogeneity among the strains probably has an impact on the extent of their interplay with PPIs. Further studies are needed to establish this correlation.

Transcriptional alteration of NF-κB-associated long noncoding RNAs in the stomach of Helicobacter pylori-infected and non-infected patients.

INTRODUCTION: Helicobacter pylori could colonize the gastric mucosa and cause gastritis, ulcers and cancer. Numerous virulence factors have been identified in this bacterium that play important roles in promoting gastric disorders. Although the interaction of long noncoding RNAs (lncRNAs) with transcription, processing, and translation of genes associated with different diseases are described, their interaction with the inflammatory genes and H. pylori infection in the gastric tissue is not well known. This study compared changes in common NF-κB-regulatory lncRNAs in the gastric tissue of H. pylori-infected and non-infected patients with gastritis. Moreover, a link between the virulence entity of the strains and the transcriptional changes was analyzed. METHODOLOGY: Two groups of infected and non-infected patients with chronic gastritis were included in the study. Genotyping of the H. pylori strains was done by PCR and relative changes in the expression of NF-κB and regulatory lncRNAs, lincRNA-p21, MALAT1, NKILA, were measured by relative quantitative real time-PCR. RESULTS: Transcriptional levels of MALAT1, lincRNA-p21, and NKILA genes decreased in the infected patients compared with the non-infected patients, which was significantly linked with increased NF-κB gene expression. Our results showed that a hypervirulent strain of H. pylori with oipA"on"/HP-NAP+/iceA1+/iceA2+/vacA s1m1/s1m2+/cagA+ genotype can promote a higher level of NF-κB transcription in the inflamed tissue. CONCLUSIONS: H. pylori infection could promote down-regulation of lincRNA-p21, MALAT1 and NKILA in the infected gastric tissue in correlation with NF-κB upregulation. More detailed studies are needed to show a link between the virulence genes and their impact on the regulation of lncRNAs in the stomach.

Pneumocystis pneumonia in COVID-19 patients: A comprehensive review.

The admitted patients of intensive care units with coronavirus disease 2019 (COVID-19) meet the challenges of subsequent infections. Opportunistic fungal infections such as Pneumocystis pneumonia (PCP) are among the important factors in the context of COVID-19 patients affecting illness severity and mortality. We reviewed the literature on COVID-19 patients with PCP to identify features of this infection. Although studies confirmed at least the presence of one immunosuppressive condition in half of PCP patients, this disease can also occur in immunocompetent patients who developed the immunosuppressive condition during Covid-19 treatment. The major risk factors associated with COVID-19 patients with PCP can be considered low lymphocyte counts and corticosteroid therapy. Diagnostic and treatment options are complicated by the overlapping clinical and radiologic characteristics of PCP and COVID-19 pneumonia. Therefore, physicians should comprehensively evaluate high-risk patients for PCP prophylaxis.

Activation of the DNA damage response pathway in the infected gastric tissue with Helicobacter pylori: a case-control study.

INTRODUCTION: Gastritis is among the most common human diseases worldwide. Although the involvement of Helicobacter pylori infection as a class I human carcinogen for gastric cancer progression is accepted, it is not well known how gastritis progression to atrophy and stomach cancer occurs. In this case-control study, the potential link of H. pylori infection with alteration in the transcription of genes involved in DNA Damage Response pathways was investigated among the patients with gastritis. METHODOLOGY: To measure the difference in the relative mRNA expression level of ATM, CHEK2, TP53, DCLRE1C, POLM, and XRCC4 genes between H. pylori-infected and non-infected patients, gastric biopsies of 30 H. pylori infected patients with moderate chronic gastritis and 30 non-infected patients with mild chronic gastritis were analyzed. RESULTS: Up-regulation of genes linked to non-homologous end joining (NHEJ) pathway (DCLRE1C, POLM, and XRCC) was shown in 40% (8.44 fold ± 13.91), 63.33% (15.72 fold ± 33.08) and 50% (9.99 fold ± 21.55), respectively, and also to DDR pathway (ATM, CHEK2, and TP53) in 33% (2.42 fold ± 3.17), 40% (2.86 fold ± 3.61) and 50% (5.00 fold ± 6.52), respectively. No correlation was detected between alteration in the transcription level of the studied genes and age or gender. CONCLUSIONS: Our results provide new data that may support the potential involvement of H. pylori infection in the activation of genes involved in DNA damage response, mainly through a non-homologous end-joining DNA repair system that might be linked to mutagenesis in the pre-cancerous gastric tissue.

Corrigendum to "Pneumocystis pneumonia in COVID-19 patients: A comprehensive review" [Heliyon 9(2) (February 2023) e13618].

[This corrects the article DOI: 10.1016/j.heliyon.2023.e13618.].

Effects of Poly-N-isopropylacrylamide Microgels Containing Antibiofilm Substances on Pseudomonas aeruginosa Isolated from Chronic Wounds.

Background: Biofilm formation helps Pseudomonas aeruginosa (P. aeruginosa) survive in various environments. Microgels can be effective in treatment of bacterial infections. The major aim of this study was to investigate effects of poly-N-isopropylacrylamide microgels (PNIPAM) on P. aeruginosa. Methods: Totally, 100 P. aeruginosa strains were isolated from chronic wound infections. Quantitative assessments of biofilm formation and antibiotic susceptibility were carried out. Furthermore, algD, lasR, and PA2714 genes were amplified to investigate gene frequencies and expression rates. Results: Significant decreases were seen in lasR expression in EDTA-treated samples. Significant decreases were observed in expression of algD and lasR treated with xylitol. Decreased expression of PA2714 was seen in samples treated with xylitol with no significance. Conclusion: The PNIPAM containing xylitol or EDTA could penetrate biofilms of P. aeruginosa and significantly decrease expression of lasR and algD. This can be a novel strategy in the management of chronic wounds.

Effect of dilution factor on the isolation of Helicobacter pylori from municipal wastewater using culture technique.

Background and Objectives: Isolating Helicobacter pylori (H. pylori) from wastewater and culturing it using a conventional method has always been a controversial issue because the bacterium converts into a coccoid form when exposed to an unfavourable environment like wastewater. To clarify the cultivability behaviour of the bacterium in fresh wastewater samples, the effect of municipal wastewater dilation on the cultivation of the bacterium using a conventional method was examined. Materials and Methods: Several dilutions of wastewater samples were inoculated with fresh H. pylori suspension (with McFarland's dilution 0.5) to examine the dilution effect of wastewater on the bacterium isolation. Results: The H. pylori growth was found to be possible for a dilution factor from 1/106 to 1/107 of raw wastewater. In higher dilution factors the growth of fungi was dominant and could prevent the isolation of the bacterium. Conclusion: The optimized technique could be applied in future studies for increasing the chance of H. pylori isolation from fresh wastewater environments.

Association between Presence of RmpA, MrkA and MrkD Genes and Antibiotic Resistance in Clinical Klebsiella pneumoniae Isolates from Hospitals in Tehran, Iran.

BACKGROUND: Klebsiella pneumoniae is an opportunistic pathogen causing nosocomial infection in human. This study aimed to investigate the relationship between the presence of genes involved in biofilm formation in K. pneumoniae isolated from patients and the presence of antibiotic resistance genes. METHODS: Biochemical tests were used for the identification of K. pneumonia isolated from urine samples referred to hospitals in Tehran, Iran, from Sep 2018 to Jan 2020. The antibiotic resistance pattern was performed and biofilm formation was assessed phenotypically. Finally, ß-lactamase genes and adhesion genes were detected by the PCR method. RESULTS: We collected 457 K. pneumoniae isolates from hospitals in Tehran, Iran. 110 isolates were resistant to imipenem. Fifty isolates were positive for metallo-ß-lactamases that thirty-nine isolates (35.45%) has blaKPC gene, 18 isolates (16.36%) had blaVIM-1 gene and 9 isolates (8.18%) had blaIMP-1 gene detected by PCR. Sixty isolates (54.54%) had strong biofilm, 35 isolates (31.81%) had moderate biofilm and 15 isolates (13.63%) had weak biofilm. The presence of adhesion genes in K. pneumoniae isolates significantly correlated with resistance genes (P<0.001). CONCLUSION: It is clear antibacterial resistance has been significant association with biofilm formation in K. pneumoniae isolates. Therefore, understanding resistance pattern and mechanisms leading to biofilm formation can facilitate efficient treatment of infections caused by K. pneumoniae.

Antibacterial effect of carbon nanotube containing chemical compounds on drug-resistant isolates of Acinetobacter baumannii.

BACKGROUND AND OBJECTIVES: Acinetobacter baumannii is recognized as an important pathogen responsible for serious infections causing episodes of hospital infection. Carbon nanotubes (CNTs) have recently emerged as superior materials against antibiotic-resistant bacteria. In this study, a new chemical compound was designed in order to combat A. baumannii infections. Subsequently, the effect of this novel carbon nanotube coated with an antibacterial compound on Extensively Drug-Resistant (XDR), Multidrug-Resistant (MDR) and Pan-Drug-Resistance (PDR) strains of A. baumannii was investigated. MATERIALS AND METHODS: A total of 122 clinical isolates of A. baumannii were cultured from burn patients and their susceptibility to antibiotics were checked using disk diffusion method and Minimum inhibitory concentration. Antimicrobial effects of the coated carbon nanotube were evaluated on XDR, MDR and PDR isolates of A. baumannii. Cell viability was determined using tetrazolium reduction assay (MTT) on human fibroblast cell line (HDFa). Wound healing processes were assessed by quantitative polymerase chain reaction. RESULTS: Of the 50 A. baumannii isolates, 38 (76%) were found to be MDR and 12 (24%) were XDR. No PDR strains were detected. Results indicated that the carbon nanotube combined with mercury had antibacterial effect against different A. baumannii species and it also was able to increase the expression of epidermal growth factor, platelet-derived growth factor and vascular endothelial growth factor A mRNA levels which are involved in wound healing. CONCLUSION: The engineered carbon nanotube compound can potentially be used for treatment of burn related infections. This can potentially give clinicians a new tool for treating A. baumannii infections.

Optimization of antimicrobial efficiency of silver nanoparticles against three oral microorganisms in irreversible hydrocolloid impressions.

BACKGROUND AND OBJECTIVES: Silver nanoparticles (Ag-NPs) are potent antimicrobial agents, which have recently been used in dentistry. The aim of the current study was to optimize antimicrobial activity of Ag-NPs used in preparing irreversible hydrocolloid impressions against three microorganisms of Escherichia coli, Streptococcus mutans and Candida albicans. MATERIALS AND METHODS: After assessing antimicrobial activity of the compound using disk diffusion method, three parameters of concentration of Ag-NPs (250-1000 ppm), ratio of hydrocolloid impression material powder to water (0.30-0.50) and time of mixing (20.0-60.0 s), affecting antimicrobial activity of irreversible hydrocolloid impression materials against the three microorganisms, were optimized. This combined process was successfully modeled and optimized using Box-Behnken design with response surface methodology (RSM). Decreases in colony number of E. coli, S. mutans and C. albicans were proposed as responses. RESULTS: Qualitative antimicrobial assessments respectively showed average zone of inhibition (ZOI) of 3.7 mm for E. coli, 3.5 mm for S. mutans and 4 mm for C. albicans. For all responses, when the mixing duration and powder-to-water ratio increased, the circumstances (mixing duration of 59.38 s, powder-to-water ratio of 0.4 and Ag-NP concentration of 992 response) increased. Results showed that in optimum ppm, the proportion of decreases in colony numbers was maximum (89.03% for E. coli, 87.08% for S. mutans and 74.54% for C. albicans). Regression analysis illustrated a good fit of the experimental data to the predicted model as high correlation coefficients validated that the predicted model was well fitted with data. Values of R2Adj with R2Pred were associated to the accuracy of this model in all responses. CONCLUSION: Disinfection efficiency dramatically increased with increasing of Ag-NP concentration, powder-to-water ratio and mixing time.

The Construction of Carbon Nanotubes Containing an Anti-Bacterial Chemical Component and its Effect on MDR and XDR Isolates of Pseudomonas Aeruginosa.

BACKGROUND: Pseudomonas aeruginosa is an opportunistic human pathogen that causes severe acute and chronic nosocomial infections, especially in immunocompromised burn patients. and can lead to severe mortality and morbidity. The emergence of antibiotic resistant P. aeruginosa infections has created significant challenges in treating these patients. A potential alternative treatment for antibiotic resistant pathogens includes the use of carbon nanotubes (CNTs), which have received considerable attention due to their potent antibacterial activity. The aim of this study was to construct a novel CNT containing an anti-bacterial chemical component to effectively combat drug resistant P. aeruginosa infections. METHODS: In this study, a novel chemical component was synthesized and coated the CNT. The antimicrobial effects were then evaluated on MDR, XDR, and PDR strains of P. aeruginosa isolated from burn patients. Antibiotic susceptibility was evaluated using the disk diffusion test and minimum inhibitory concentration (MIC) testing. In order to determine the potential cytotoxicity, an MTT assay was performed on Human Dermal Fibroblasts. The effect of treatment on the expression of wound healing genes was analyzed via qRT-PCR. RESULTS: Experimental data indicates that our CNT coated chemical compound had antibacterial properties, negligible cytotoxicity, and could accelerate the wound healing process. CONCLUSION: Given the antibacterial properties of our CNT chemical compound, it has the potential to treat and reduce the occurrence of multi-drug resistant P. aeruginosa burn wound infections and aid in wound healing by turning on genes (VEGFA, EGF and PDEGF) involved in the wound healing process.

Comparison of the effect of regular and probiotic cake (Bacillus coagulans) on salivary pH and Streptococcus mutans count.

BACKGROUND: Dental caries is considered the most common infectious disease in humans worldwide. Cariogenesis is the outcome of a complex interaction between the host's oral flora and diet. The consumption of snacks such as cake, which have the potential to promote dental caries, has increased. OBJECTIVES: The aim of this study was to investigate the effect of including probiotic bacteria (Bacillus coagulans - B. coagulans) in consumed snack cake on the Streptococcus mutans (S. mutans) count and salivary pH. MATERIAL AND METHODS: We conducted a randomized, double-blind, cross-sectional cohort study on 40 healthy volunteers. The subjects were divided into 2 groups. In the 1st group, the subjects consumed probiotic cake as breakfast for 1 week and then, following a 4-week wash-out period, consumed regular cake as breakfast for 1 week. In the other group, the administration of probiotic and regular cake was reversed. For both groups, samples of at least 5 mL of non-stimulated saliva were collected using the spitting technique before and after the 1st and the 6th week. A colony counter was used to determine the number of S. mutans colonies. Salivary pH was measured before eating (8-9 a.m.). RESULTS: We detected no statistically significant difference in the S. mutans count before and after the consumption of probiotic cake, but noted a statistically significant difference in the count before and after the consumption of regular cake. We did not detect a significant difference in salivary pH with respect to the consumption of probiotic and regular cake, although the consumption of both foods caused a drop in salivary pH. CONCLUSIONS: The addition of probiotic bacteria to sweet snack cake caused a minimal increase in the salivary count of S. mutans, a bacterial species with a definite role in cariogenesis, but did not impact salivary pH. Since probiotic cake has a slight impact on the S. mutans count, it is preferred over regular cake as a snack food.