Evaluation of surface energy and surface stability and adherence of Candida albicans to octa fluoro pentyl (meth) acrylate-coated PEEK using plasma spray.

Background: Polyetheretherketone (PEEK) has favorable properties that make it able to be used as a denture base material, but it is also susceptible to the adhesion of microorganisms. In this study, we applied Octafluoropentyl (meth) acrylate (OFPA) coating on the PEEK polymer surface by using plasma spray and investigated the functional groups present on the surface, changes in the surface energy and Candida albicans adhesion. Materials and Methods: In this experimental study, the samples were placed in a control group without surface preparation and three experimental groups that were subjected to plasma spray for 10, 30, and 60 s and then impregnated with degassed Octa fluoropentyl (meth) acrylate (Sigma-Aldrich, USA) monomer. Fourier transform infrared spectroscopy (FTIR) was used to identify the functional groups and new chemical bonds between PEEK and OFPA, and Sessile Drop Method was used to evaluate the surface's wettability. The surface morphology was checked using a LEXT OLS4000 (Olympus®-Japan) microscope, and the inhibition of C. albicans adhesion was also checked by counting the colonies in terms of colony forming unit/mL (CFU/mL). Kurskal-Wallis analysis was conducted to assess Candida adhesion, while wettability was evaluated using analysis of variance and post hoc analyses. The level of statistical significance was set at P < 0.05. Results: FTIR analysis confirmed that a chemical between OFPA and PEEK was established. The samples showed a significant increase in the contact angle after 30 s of plasma application (CA = 88.2 ± 7.3). The contact angle decreased again by increasing the surface modification to 60 s (CA = 64.33 ± 5.5). Examining the surface morphology of the samples shows an increase in surface roughness with increasing plasma time up to 60 s. The number of adherent colonies was the lowest in 30 s group, but it was not statistically significant (P = 0.658). Conclusion: No statistically significant difference in C. albicans CFU/mL count was found between groups. The contact angle of the 30 s group was significantly higher than the control group.

Phage therapy as a glimmer of hope in the fight against the recurrence or emergence of surgical site bacterial infections.

PURPOSE: Over the last decade, surgery rates have risen alarmingly, and surgical-site infections are expanding these concerns. In spite of advances in infection control practices, surgical infections continue to be a significant cause of death, prolonged hospitalization, and morbidity. As well as the presence of bacterial infections and their antibiotic resistance, biofilm formation is one of the challenges in the treatment of surgical wounds. METHODS: This review article was based on published studies on inpatients and laboratory animals receiving phage therapy for surgical wounds, phage therapy for tissue and bone infections treated with surgery to prevent recurrence, antibiotic-resistant wound infections treated with phage therapy, and biofilm-involved surgical wounds treated with phage therapy which were searched without date restrictions. RESULTS: It has been shown in this review article that phage therapy can be used to treat surgical-site infections in patients and animals, eliminate biofilms at the surgical site, prevent infection recurrence in wounds that have been operated on, and eradicate antibiotic-resistant infections in surgical wounds, including multi-drug resistance (MDR), extensively drug resistance (XDR), and pan-drug resistance (PDR). A cocktail of phages and antibiotics can also reduce surgical-site infections more effectively than phages alone. CONCLUSION: In light of these encouraging results, clinical trials and research with phages will continue in the near future to treat surgical-site infections, biofilm removal, and antibiotic-resistant wounds, all of which could be used to prescribe phages as an alternative to antibiotics.

Molecular study on virulence and resistance genes of ST131 clone (uropathogenic/enteropathogenic Escherichia coli) hybrids in children.

Aim: To analyze ST131 clones and other characteristics in uropathogenic and atypical enteropathogenic Escherichia coli hybrids. Methods: Samples were collected from children with urinary tract infections and underwent testing for antimicrobial susceptibility, multidrug resistance and extended-spectrum ß-lactamases, in vitro biofilm formation and virulence, resistance genes, hybrid pathotypes and ST131 clones. Results: E. coli isolates showed high levels of antibiotic resistance, extended-spectrum ß-lactamase production, virulence genes, multidrug resistance and biofilm formation. Four (5.0%) isolates were identified as uropathogenic/atypical enteropathogenic E. coli hybrids, all of which belonged to the high-risk ST131 clone. Conclusion: Our results provide promising insights about hybrid isolates and should be addressed to improve prevention measures for hybrid pathotypes.

Acrylamide content of industrial and traditional popcorn collected from Tehran's market, Iran: A risk assessment study.

Acrylamide as a probable human carcinogen can be produced via the Maillard reaction between asparagine and reducing sugars at high temperatures during food processing. In this study, the concentration of acrylamide in industrial and traditional popcorn sold in Tehran, Iran in the spring of 2021 was analyzed. Industrial popcorn is popcorn that has a manufacturing license from the health authorities. Traditional popcorn is sold by retailers in entertainment centers. Estimated daily intake (EDI) and margin of exposure (MOE) for neurological changes and neoplastic effects have been estimated. The values of limit of detection (LOD) and limit of quantitation (LOQ) were determined as 3.1 and 10.2 ng/mL, respectively. The amount of acrylamide was measured ranging from nondetectable up to 14.8 mg/kg. Acrylamide was detected in 86% of samples. The level of acrylamide in most popcorn samples has been detected as greater than LOD and LOQ. The average content of acrylamide in traditional popcorn was determined to be 7.7 mg/kg which was higher than the average value of 3.08 mg/kg found in industrial popcorn. Significant difference was observed between industrial and traditional popcorn samples. The average intake of popcorn for adolescent population was estimated as 2 g per day. EDI was calculated as 0.3 and 0.12 µg/kg of body weight per day for the traditional and industrial popcorn. These results indicated that popcorn can be considered a potential source of acrylamide exposure in the adolescent population. Furthermore, if the actual MOEs for neurological and neoplastic effects are estimated to be less than 10 000, it is considered a health risk. In this study, MOE has been estimated lower than 10 000 for neurological changes and neoplastic effects.

The genotypic and phenotypic characteristics contributing to high virulence and antibiotics resistance in Escherichia coli O25-B2-ST131 in comparison to non- O25-B2-ST131.

BACKGROUND: Escherichia coli serogroup O25b-sequence type 131 (E. coli O25-B2-ST131) is considered as multidrug-resistant and hypervirulent organism. There is lack of data about involvement of this pathogen in the children's infection. In this study, the prevalence, and clonality, virulence capacity, and antibiotic resistance phenotype and genotype of E. coli O25-B2-ST131 compared with non-O25-B2-ST131 isolates were investigated in children with urinary tract infection in Tehran, Iran. METHODS: The E. coli isolates from urine samples were identified using conventional microbiological methods. Characterization of E. coli O25-B2-ST131 clone, antibiotic susceptibility, biofilm formation, ESBLs phenotype and genotype, serum resistance, hemolysis, hydrophobicity, and formation of curli fimbriae were done using conventional microbiological and molecular methods. Clonality of the isolates was done by rep-PCR typing. RESULTS: Among 120 E. coli isolates, the highest and lowest antibiotic resistance was detected against ampicillin (92, 76.6%) and imipenem 5, (4.1%), respectively. Sixty-eight (56.6%) isolates were ESBL-producing and 58 (48.3%) isolates were considered as multi-drug resistance (MDR). The prevalence of ESBL-producing and MDR isolates in O25-B2-ST131 strains was higher compared with the non-O25-B2-ST131 strains (p value < 0.05). O25-B2-ST131 strains showed significant correlation with serum resistance and biofilm formation. Amongst the resistance and virulence genes, the prevalence of iucD, kpsMTII, cnf1, vat, blaCTX-M-15, and blaSHV were significantly higher among O25-B2-ST131 isolates in comparison with non-O25-B2-ST131 isolates (p value < 0.05). Considering a ≥ 80% homology cut-off, fifteen different clusters of the isolates were shown with the same rep-PCR pattern. CONCLUSIONS: Our results confirmed the involvement of MDR-ESBLs producing E. coli strain O25-B2-ST131 in the occurrence of UTIs among children. Source tracking and control measures seem to be necessary for containment of the spread of hypervirulent and resistance variants in children.

Anti-bacterial properties of calcium hydroxide in combination with silver, copper, zinc oxide or magnesium oxide.

Prevention of bacterial growth among root canal treatment sessions is a prerequisite for successful root canal treatment. The most common way to achieve this is to use calcium hydroxide in the treatment sessions. Some studies have shown calcium hydroxide inefficiency in this field. The aim of this study was to investigate and compare the effects of silver, copper, zinc oxide and magnesium oxide nanoparticles on the inhibitory effects of calcium hydroxide based on Enterococcus faecalis species. Enterococcus faecalis bacteria having 0.5 McFarland concentration were prepared. Plates containing BHI agar medium were prepared. In each plate, four wells were created and the plate was cultured using a sterile swab. Afterwards, calcium hydroxide composition of 1% and 2% concentration from silver, copper, zinc oxide and magnesium oxide nanoparticles were prepared separately, as well as the combination of calcium hydroxide with 1% silver in combination with 1% of copper, zinc oxide and magnesium oxide nanoparticles, which were then transferred to the wells. After 24 hours of incubation, the inhibition zone diameter was measured. Data were analyzed by Mann-Withney test. At 1% concentration, only the combination of copper nanoparticles with calcium hydroxide could significantly create an inhibition zone larger than calcium hydroxide alone (P value <0.5). At 2% concentration, the combination of copper nanoparticles with calcium hydroxide, and the combination of silver nanoparticles with calcium hydroxide, were significantly higher than calcium hydroxide alone (P value <0.5). The calcium hydroxide composition containing 1% silver nanoparticles in combination with 1% copper, zinc oxide and magnesium oxide nanoparticles significantly increased the growth inhibition zone more than calcium hydroxide alone. (P Value <0.5). Copper nanoparticles showed the best antibacterial properties among silver, copper, magnesium oxide and zinc oxide nanoparticles in combination with calcium hydroxide. Also, the combination of 1% of nanoparticles with each other increases antibacterial properties.

Cell Toxicity and inhibitory effects of Cyperus rotundus extract on Streptococcus mutans, Aggregatibacter actinomycetemcomitans and Candida albicans.

Periodontitis and tooth decay are common dental diseases. There are some bacterial risk factors such as Streptococcus mutans, Aggregatibacter actinomycetemcomitans and Candida albicans complications, tubers of Cyperus rotundus was used to determine the antimicrobial effect of fungi. Considering the increasing resistance of bacteria and fungi to antibiotics and their alcoholic and aqueous extracts and essential oil on Streptococcus mutans, Aggregatibacter actinomycetemcomitans and Candida albicans, as well as an examination cytotoxicity on gingival fibroblast cells. Alcoholic and aqueous extracts and essential oil prepared from tubers of Cyperus rotundus. After bacterial and fungal cultures, the inhibition zone, Minimum inhibitory concentrations (MIC), and Minimum Bactericidal Concentration (MBC), were studied. Cytotoxicity was also evaluated using the Methyl tetrazolium test (MTT).The results showed that Cyperus rotundus alcoholic extract had the greatest effect on inhibition of growth and death of Streptococcus mutans, Aggregatibacter actinomycetemcomitans. According to the present study, Cyperus rotundus extract can be considered as a suitable candidate for the treatment and prevention of periodontitis and tooth decay.

Screening of SDS-degrading bacteria from car wash wastewater and study of the alkylsulfatase enzyme activity.

BACKGROUND AND OBJECTIVES: Sodium dodecyl sulfate (SDS) is one of the main surfactant components in detergents and cosmetics, used in high amounts as a detergent in products such as shampoos, car wash soap and toothpaste. Therefore, its bioremediation by suitable microorganisms is important. Alkylsulfatase is an enzyme that hydrolyses sulfate -ester bonds to give inorganic sulfate and alcohol. The purpose of this study was to isolate SDS-degrading bacteria from Tehran city car wash wastewater, study bacterial alkylsulfatase enzyme activity and identify the alkylsulfatase enzyme coding gene. MATERIALS AND METHODS: Screening of SDS-degrading bacteria was carried out on basal salt medium containing SDS as the sole source of carbon. Amount of SDS degraded was assayed by methylene blue active substance (MBAS). RESULTS AND CONCLUSION: Identification of the sdsA gene was carried by PCR and subsequent sequencing of the 16S rDNA gene and biochemical tests identified Pseudomonas aeruginosa. This bacterium is able to degrade 84% of SDS after four days incubation. Bacteria isolated from car wash wastewater were shown to carry the sdsA gene (670bp) and the alkylsulfatase enzyme specific activity expressed from this gene was determined to be 24.3 unit/mg. The results presented in this research indicate that Pseudomonas aeruginosa is a suitable candidate for SDS biodegradation.

Comparison of the bactericidal efficacy of photodynamic therapy, 2.5% sodium hypochlorite, and 2% chlorhexidine against Enterococcous faecalis in root canals; an in vitro study.

BACKGROUND: Enterococcus faecalis has been widely used as a valuable microbiological pathogen for in vitro studies due to its ability to successfully colonize the root canal in a biofilm-like style, invade dentinal tubules, and resist endodontic treatment procedures.The aim of this study was to compare the bactericidal efficacy of photodynamic therapy (PDT), 2% chlorhexidine, 2.5% NaOCl, and combination of PDT and 2.5% NaOCl against E. faecalis. MATERIALS AND METHODS: Sixty single-rooted teeth had their canals contaminated with E. faecalis in brain heart infusion broth and were incubated for 48 hours.The canals were then subjected to 2% chlorhexidine, 2.5% NaOCl, PDT (red light emitting diode 625 nm+ Toludine Blue) and PDT + 2.5% NaOCl. Controls consisted of no treatment (positive control) and without inoculation of bacterium (negative control). Following treatment, the canal contents were sampled with sterile paper points.The samples were dispersed in transport medium, serially diluted, and cultured on blood agar to determine the number of colony forming units (CFU). Data were analyzed by Mann-Whitney U test at 5% significance level. The significance level for all analyses was set at P <.05. RESULTS: Combination of PDT and 2.5% NaOCl achieved maximum reduction in recovered viable bacteria, no viable bacteria was observed after treatment of PDT + 2.5% NaOCl. CONCLUSION: Combination of PDT and 2.5% NaOCl simultaneously is effective in the elimination of E. faecalis from dentinal tubules under the conditions of this study.