Browsing by Author "Demirbilek, Muge"

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Biofilm-forming capacity of blood-borne Candida albicans strains and effects of antifungal agents
(2018) Demirbilek, Muge; Turan, Hanni; 28988900
Infections related to Candida albicans biofilms and subsequent antifungal resistance have become more common with the increased use of indwelling medical devices. Regimens for preventing fungal biofilm formation are needed, particularly in high-risk patients. In this study, we investigated the biofilm formation rate of multiple strains of Candida albicans (n = 162 clinical isolates), their antifungal susceptibility patterns, and the efficacy of certain antifungals for preventing biofilm formation. Biofilm formation was graded using a modified Christensen's 96-well plate method. We further analyzed 30 randomly chosen intense biofilm-forming isolates using the XTT method. Minimum biofilm inhibition concentrations (MBIC) of caspofungin, micafungin, anidulafungin, fluconazole, voriconazole, posaconazole, itraconazole, and amphotericin B were determined using the modified Calgary biofilm method. In addition, the inhibitory effects of antifungal agents on biofilm formation were investigated. Our study showed weak, moderate, and extensive biofilm formation in 29% (n = 47), 38% (n = 61), and 23% (n = 37) of the isolates, respectively. We found that echinocandins had the lowest MBIC values and that itraconazole inhibited biofilm formation in more isolates (26/32; 81.3%) than other tested agents. In conclusion, echinocandins were most effective against formed biofilms, while itraconazole was most effective for preventing biofilm formation. Standardized methods are needed for biofilm antifungal sensitivity tests when determining the treatment and prophylaxis of C. albicans infections. (c) 2017 Asociacion Argentina de Microbiologia. Published by Elsevier Espana, S.L.U.
Comparison between corneal cross-linking, topical antibiotic and combined therapy in experimental bacterial keratitis model
(2018) Demirbilek, Muge; Kilic, Begum Bulam; Altiors, Dilek Dursun; Ogus, Ersin; 0000-0002-9877-421X; 29942176; AAJ-1058-2021
Purpose: This study was conducted to investigate the effects of an experimental bacterial keratitis model on the corneal collagen cross-linking treatment (CXL), and also to compare topical antibiotic treatment with the combined treatment. Methods: The study involved 40 young adult female Sprague Dawley rats, which had a 2 mm scraped defect of the central corneal epithelium in both eyes. The rats were divided into two equal groups. The first group was inoculated in both eyes with standard Pseudomonas Aeruginosa (PA) from a strain suspension prepared from 0.05 ml (Group 1), and the second group was inoculated with standard Methicillin Resistance Staphylococcus Aureus (MRSA) strains from a suspension prepared from 0.05 ml (Group 2). Group 1 was divided into four sub-groups: Group 1A was treated by collagen cross-linking (CXL), Group 1C was treated with topical tobramycin drops CXL and also treated by collagen cross-linking (CXL), Group 1D was treated with topical tobramycin drops, and Group 1B was left untreated in order to create a control group. Similarly, Group 2 was also divided into four sub-groups: Group 2A was treated by CXL, Group 2C was treated with topical 5% fortified vancomycin drops CXL and also treated by CXL, Group 2D was treated with topical 5% fortified vancomycin drops, and Group 2B was left untreated in order to create a control group. CXL was performed on the third day following the inoculation and topical drop therapy. Biomicroscopy and microbiologic assessments were performed on the third and seventh days following the inoculation of microorganisms. Results: In the treatment, which compared baselines in all groups before treatment, the diameter of keratitis infiltrations, corneal clouding, and corneal swab samples were obtained from the reduction in reproduction. The results were statistically significant (p < 0.01). Keratitis infiltration groups were conducted on the seventh day for Groups 1C and 1D according to Group 1B, whilst Groups 2A, 2C and 2D were conducted according to Group 2B, which showed a significant statistical reduction (p < 0.01). On the seventh day, focal groups were conducted in corneal clouding Group 1D according to Group 1B and in Groups 2A, 2C and 2D according to Group 2B, which revealed a significant statistical reduction (p < 0.01). On the seventh day, reproduction in culture was obtained from corneal swab samples in Groups 1C and 1D according to Group 1B; in Groups 1C and 1D according to Group 1A; in Groups 2A, 2C and 2D according to Group 2B; and in Group 2C according to Group 2A, where a significant statistical reduction was observed (p < 0.01). Conclusions: The clinical and microbiological efficacy of the CXL treatment is evaluated in our study. In accordance with the conclusion reached an effective reduction in the density and severity of (infection), occurred as a result of CXL treatment, CXL treatment combined with topical antibiotic treatment and topical antibiotic treatment of Pseudomonas Aeruginosa (PA) and Metisilin Rezistant Staphylococcus Aureus (MRSA) keratitis infections. From these results, it is shown that topical antibiotics and CXL potentiate each other's effects in the treatment of resistant bacterial keratitis.
Effects of various analgesics on the level of prostaglandin E2 during orthodontic tooth movement
(2014) Tuncer, Zeynep; Polat-Ozsoy, Omur; Demirbilek, Muge; Bostanoglu, Ebru
AIM: The aim of this double-blind, randomized, placebo-controlled clinical study was to evaluate the analgesic effects of preoperative/postoperative ibuprofen and acetaminophen use after bonding and to find a relation between the pain level and the amount of prostaglandin released. MATERIALS AND METHODS: Forty-eight patients were included and randomly divided to three equal groups that received either ibuprofen, acetaminophen or placebo for pain relief. The pain levels were measured before bonding, after bonding, at first, second, third, and seventh days on a 100 mm visual analogue scale (VAS) and gingival crevicular fluid (GCF) samples were collected at the same time intervals to measure the amount of prostaglandin E2 (PGE2) released. PGE2 levels were determined with ELISA test. The results were evaluated with Wilcoxon and Kruskal-Wallis tests with Bonferroni correction. RESULTS: Acetaminophen and placebo groups showed similar pain levels during the first 2 days, whereas ibuprofen group showed lower pain levels during the first day after bonding. PGE2 levels did not show statistically significant difference in time within the analgesic groups. No significant relation between the pain perceived and PGE2 released was found. LIMITATIONS: The biggest limitation of this study is the subjective nature of pain and its method of evaluation. CONCLUSIONS: The perception of pain by patients taking ibuprofen and acetaminophen at pre/post appliance placement was not different from patients taking placebo. No time-related differences in PGE2 level were found between the groups and no significant correlation was found between the perception of pain and PGE2 levels.
Efficacy of Multipurpose Contact Lens Solutions Against ESBL-Positive Escherichia coli, MRSA, and Candida albicans Clinical Isolates
(2014) Demirbilek, Muge; Evren, Ebru; 24756120; JWP-3001-2024
Objectives: The antimicrobial effects of multipurpose contact lens solutions (MPSs) have been evaluated according to ISO 14729 standards. The aim of this study was to assess the efficacy of commercially available MPSs against extended-spectrum beta lactamases (ESBL)-producing Escherichia coli, methicillin-resistant Staphylococcus aureus (MRSA), and Candida albicans clinical isolates. Methods: Three commercially available contact lens solutions (Opti-Free Expresss, ReNu MultiPlus, and Solo Care Aqua) were tested against 18 ESBL-positive E. coli clinical strains, 20 MRSA clinical strains, and 20 C. albicans clinical strains. The stand-alone assays for bacteria and fungi were performed according to ISO 14729 criteria, and all samples were evaluated after 2, 4, and 24 hours of incubation. The numbers of viable microorganisms were evaluated by the plate-counting method. Results: All MPSs demonstrated at least 3 log reduction in colony-forming units (CFU) for all bacterial isolates and 1 log reduction in CFU for all yeast isolates, which meets ISO 14729 standards. Although no statistically significant differences were obtained among MPSs for bacterial isolates, variable responses were observed against clinical isolates: 5% povidone-iodine was more effective compared with Solo Care Aqua for C. albicans clinical strains (P<0.05); and all solutions were effective after an incubation time of only 2 hrs. The MPSs showed good activity against S. aureus, E. coli, and C. albicans. Conclusions: Although effective log reductions were provided with all MPSs, the reduction was variable depending on the strains tested. Multipurpose contact lens solutions should be tested under ISO 14729 standards for both standard and clinical strains.
In Vitro Evaluation of E. coli And S. epidermidis Adhesion on Dressing Materials Used in Hypospadias Repair
(2014) Soyer, Tutku; Bostanoglu, Ebru; Aslan, Mustafa Kemal; Boybeyi, Ozlem; Demirbilek, Muge; Gocmen, J. Sedef; JWP-3001-2024
Background An in vitro study was performed to evaluate the adherence of Escherichia coli and Staphylococcus epidermidis to different dressing materials. Methods Hydrophyl gauze swab (GS), sterile flax swab (FS), and their nitrofurazone (Furacin (R)) absorbed forms (GSF and FSF), sterile paraffin-covered gauze with chlorhexidine acetate (0.5 %) (Bactigrass (R), BG), and semipermeable transparent film gauze (Tegaderm (R), TG) were used in the study. A 1 cm(2) of each material was placed in culture plates, and E. coli ATCC 25922 and S. epidermidis ATCC 12228 were suspended in each plate. After 24, 48 h, and 1 week of incubation period, colony counts were calculated in colony-forming units (CFU) per square centimeter unit. Bacterial adhesion was compared between groups, and each dressing material was also compared for different incubation periods (24, 48 h, and 1 week). Results The colony counts were significantly decreased in GSF and FSF groups (Kruskal-Wallis test, p < 0.05). There was no difference for E. coli adhesion in GS, FS, BG, and TG groups (p > 0.05). The significant difference detected for S. epidermidis adhesion in the first 24 to 48 h could not be detected at the end of a 1-week period. There was no statistical difference in groups when compared for 24-, 48-h, and 1-week periods of incubations (Wilcoxon signed-rank test, p > 0.05). In BG group, E. coli adhesion was increased, and S. epidermidis adhesion was decreased without a significant difference at the end of a 1-week period (p > 0.05). Conclusions Nitrofurazone absorbed sterile gauze materials have less bacterial adhesion. In vitro adhesion of E. coli and S. epidermidis did not differ between the 24-h and 1-week period. E. coli adhesion to BG can be increased if the duration of dressing prolonged up to a 1-week period. Level of Evidence: Not ratable.