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Öğe Anticandidal activities of lactic acid bacteria isolated from the vagina(Tübitak Scientific & Technical Research Council Turkey, 2019) Er, Sevda; İstanbullu Tosun, Ayşe; Arık, Gizem; Kıvanç, MerihBackground/aim: Lactic acid bacteria prevent the overgrowth of pathogenic agents and opportunistic pathogens in the vagina. Moreover, lactic acid bacteria contribute to the preservation of vaginal microbiota by producing antimicrobial agents. Previous studies showed that some lactic acid bacteria exhibited antimicrobial activity against Candida species causing yeast vaginosis as well as many bacterial pathogens. Materials and methods: The antifungal activities of various lactic acid bacteria isolated from the vagina of healthy women on some Candida species isolated from the vagina were investigated by agar diffusion technique. Results: Most of the lactic acid bacteria that belong to the species of Lactobacillus crispatus, L. fermentum, L. acidophilus, L. paracesei subsp. paracesei, L. pentosus, and L. plantarum exhibited antifungal activity in varying ratios against C. albicans, C. glabrata, and C. tropical is strains isolated from the vagina. Conclusion: The lactic acid bacteria are useful microorganisms associated with a variety of probiotic properties. In this sense, our lactic acid bacteria isolates with high antifungal activity may be promising candidates as probiotic microorganisms in the inhibition of vaginal candidiasis, which is one of the most prevalent problems, or in the protection against candidiasis. We will continue our studies in this area.Öğe Cytotoxic effects of various lactic acid bacteria on Caco-2 cells(Scientific and Technical Research Council of Turkey, 2015) Er, Sevda; Koparal, Ayşe Tansu; Kıvanç, MerihProbiotics are live microbial food supplements that can be considered a functional food. They benefit the health of a host animal by maintaining their intestinal microbial balance. Most probiotic microorganisms are lactic acid bacteria (LAB) such as Lactobacillus spp., Bifidobacterium spp., and Enterococcus spp. LAB have been reported to possess certain anticancer properties. The vast majority of studies on their anticancer effects have dealt with colorectal cancers, although there have also been some studies on breast and bladder cancers. Colon cancer is the fourth most common cause of cancer-related mortality in the world. The aim of this study was to investigate the antiproliferative effects of the cell-free filtrate and the cell-free lyophilized filtrate of 3 LAB (Pediococcus pentosaceus, Lactobacillus plantarum, and Weissella confusa) on human colorectal adenocarcinoma cell line Caco-2. The filtrates were found to inhibit the growth of colon cancer cells in a dose-dependent manner as detected by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, suggesting that these strains might have use as probiotics in functional food or for colon cancer treatment. There are no other studies related to the anticancer activities of W. confusa in the literature.Öğe Cytotoxic effects of Weissella confusa on human colon adenocarcinoma cells (Caco-2 cells)(Wiley-Blackwell, 2011) Er, Sevda; Koparal, Ayşe T.; Kıvanç, Merih[Abstract Not Available]Öğe Design and characterization of nanocarriers loaded with Levofloxacin for enhanced antimicrobial activity; Physicochemical properties, in vitro release and oral acute toxicity(Faculdade de Ciencias Farmaceuticas (Biblioteca), 2019) Siafaka, Panoraia; Okur, Mehmet Evren; Ayla, Şule; Er, Sevda; Çağlar, Emre Şefik; Okur, Neslihan ÜstündağInorganic and carbon based nanomaterials are widely used against several diseases, such as cancer, autoimmune diseases as well as fungi and bacteria colonization. In this work, Santa Barbara Amorphous mesoporous silica (SBA), Halloysite Nanotubes (HNTs) and Multiwalled Carbon Nanotubes (CNTs) were loaded with fluoroquinolone Levofloxacin (LVF) to be applied as antimicrobial agents. The prepared via adsorption nanocarriers were characterized by Fourier-Transformed Spectroscopy, Scanning Electron Microscopy as well as High Pressure liquid Chromatography. In vitro release studies were carried out using Simulated Body Fluid at 37°C and data analyzed by various kinetic models showing slow dissolution over 12-24 hours. Antimicrobial studies showed improved antibacterial activity against Escherichia coli, Enterococcus faecalis, Listeria monocytogenes, Staphylococcus aureus, and Staphylococcus epidermidis compared to neat nanomaterials. CNTs were found to be the most promising candidates for LVF delivery and they were chosen to be further studied for their acute oral toxicity and histopathological examination using C57/Black mice. Histological examination depicted that drug loading did not affect mice organs morphology as well as hepatocyte degeneration, central vein degeneration and parenchymal necrosis scores. To conclude, the prepared nanomaterials present significant characteristics and can act as antimicrobial drug carriers; CNTs found to be safe candidates when orally fed to mice.Öğe Farklı periodontopatojenlerin RAW 264.7 makrofajları tarafından fagositozunun değerlendirilmesi(Ege Üniversitesi, 2020) Balcı, Nur; Salehli, Adile; Toksöz, Esat Buğrahan; Çetin, Metin; Yılmaz, Melis; Er, SevdaAmaç: Periodontitis, spesifik periodontal patojenlerin ileri doku kaybına neden olduğu kronik inflamatuar bir hastalıktır. Kronik inflamatuar hastalıklarda, bakterilerin makrofaj gibi özel fagositik hücreler tarafından fagositozu, inflamasyonun çözünmesi için önemlidir. Periodontal hastalıklardaki çeşitli bakteriler, fagositoz mekanizmasına karşı farklı davranışlar sergileyebilmektedir ve bununla ilgili bilgiler sınırlıdır. Bu nedenle farklı suşların spesifik patojenik davranışlarının periodontitisteki rolünü daha iyi anlamak için Enterococcus faecalis ve Prevotella intermedia'nın fagositozunu araştırmayı amaçladık.Yöntem: Çalışmada E. faecalis ve P. intermedia ağız klinik izolatları, RAW 264.7 makrofaj hücreleriyle 37 ° C ’de % 5 CO2ortamında 1 saat inkübe edilmiştir. Floresanla etiketlenen bakterilerin fagositozunu ölçmek için akım sitometrisi yöntemi kullanılmıştır.Bulgular: Çalışmada elde edilen veriler, E. faecalis bakterisinin RAW 264.7 makrofaj hücreleri tarafından fagositoza önemli ölçüde dirençliolduğunu, ancak P. intermedia'nın dirençli olmadığını göstermiştir (p <0.05).Sonuç: Bu çalışma, periodontal hastalık patogenezinde görülen farklı bakteri türlerinin makrofajların fagositozuna yatkınlığıarasında bir fark olduğunu göstermektedir ve E. faecalis fagositoza karşı direnç göstermektedir.Öğe Formulation of microemulsions for dermal delivery of Cephalexin(University of Istanbul, 2017) Üstündağ Okur, Neslihan; Er, Sevda; Çağlar, Emre Şefik; Ekmen, Tarık Ziya; Sala, FurkanIntroduction: Cephalexin monohydrate (CEM) is mostly used because of its activity against both the gram-positive and gram-negative microorganisms for infections. Microemulsions offer numerous advantages for dermal delivery of drugs. Objective: The objective of the present study was to prepare novel CEM loaded microemulsions and to characterize formulations, to evaluate their in vitro release profiles and antibacterial activities. Method: CEM loaded formulations [0.02% (w/w)] were characterized according to their droplet size, zeta potential, PDI, pH, electrical conductivity and viscosity. In addition, in vitro drug release studies and antibacterial activity tests were performed. Results: The developed CEM loaded microemulsions (M1 and M2) achieved narrow droplet size distribution (152.75±4.85 and 128.05±9.22), low PDI (0.364±0.05 and 0.489±0.06), suitable pH (5.28-4.84) and conductivity (342±4.472-374±5.477 µS/cm). Zeta potential was measured as 0.209±0.041 and 0.141±0.024 mV. M1CEM showed 100% release at the 7th hour and was provided almost the same zone diameter as CEM solution when evaluated for antibacterial activity. Conclusion: Overall, it was concluded that microemulsions might be beneficial in improving dermal delivery of CEM for the treatment of skin and soft tissue infections.Öğe Identifying probiotic characteristics of lactobacillus crispatus isolated from the vagina(University of São Paulo, 2019) Er, Sevda; Erim, Ümit Can; Koç, Fatma; Kıvanç, MerihLactobacilli prevent overproduction of pathogenic microorganisms and contribute protecting vaginal microbiota. Many probiotic microorganisms are categorized as Lactic Acid Bacteria. In this study, it was aimed identifying probiotic characteristics of Lactobacillus crispatus isolated from the vagina of a healthy woman. For this purpose, lactic acid, hydrogen peroxide and proteolytic activity quantities and auto-aggregation, co-aggregation and hydrophobicity abilities of Lactobacillus crispatus, which has been isolated and identified by 16s rRNA sequence analysis, were determined. Additionally, bile salt and acid resistance, along with antibiotic susceptibility of Lactobacillus crispatus were analyzed by the end of 3 hours. Lactic acid, hydrogen peroxide and proteolytic activity quantities of Lactobacillus crispatus were measured 2.275%, 0.334±0.075 µg/mL and 2.131±0,000 mg/mL respectively. The findings include existence of co-aggregation and auto-aggregation ability, but not hydrophobicity. By the end of 3 hours, the viability was preserved in 0.1% and 0.3% bile salt medium and, at pH 3. L. crispatus exhibited resistance to methicillin, metronidazole, oxacillin, and sulfamethoxazole + trimethoprim, but the bacteria exhibited susceptibility to tested the other antibiotics. This study will make an important contribution to the literature about probiotic characteristics of L. crispatus and our strain isolated from the vagina might be considered as a candidate probiotic.Öğe In vitro activities of colistin, tigecycline and tobramycin, alone or in combination, against carbapenem-resistant enterobacteriaceae strains(Elsevier, 2015) Özbek, Berna; Mataracı Kara, Emel; Er, Sevda; Özdamar, Melda; Yılmaz, MesutThe aim of this study was to investigate the activities of various antibiotics, alone or in combination, against carbapenem-resistant Enterobacteriaceae (CRE). Minimum inhibitory concentrations (MICs) of meropenem, colistin, tigecycline and tobramycin were determined by microbroth dilution against 40 clinical strains. Carbapenemase-encoding genes were detected by PCR using specific primers. The in vitro synergistic activities of tigecycline, colistin and tobramycin in double antibiotic combinations were determined by the microbroth chequerboard technique, and results were interpreted using the fractional inhibitory concentration index (FICI). To confirm the results acquired by the chequerboard method, time-kill assays were performed on eight isolates representing four different susceptibility patterns. Based on MIC90 values, colistin was the most potent agent, followed by tigecycline and tobramycin. According to PCR studies, carbapenem resistance in tested Enterobacteriaceae isolates was most often mediated by OXA-48-type carbapenemases. With an FICI of <= 0.5 as the cut-off, synergistic interactions were most frequent with tigecycline + tobramycin (30%); other results for synergistic interactions were 23% for colistin + tobramycin and 9% for colistin + tigecycline. By time-kill assays, all tested antibiotic combinations demonstrated synergistic activity against at least three of the eight strains at 1x or 4x MIC. Overall, the combinations used in this study were effective regimens, demonstrating synergy or no interaction (indifference) against all tested strains. No antagonism was observed with either of the techniques. The findings of this study might play a useful role in selecting appropriate combinations when a single agent is inadequate against CRE strains.Öğe Investigation of antimicrobial activities of some herbs containing essential oils and their mouthwash formulations(Turkish Pharmacists Association, 2018) Kulaksız, Büşra; Er, Sevda; Üstündağ Okur, Neslihan; Saltan İşcan, GülçinObjectives: The aim of this study was to prepare pharmaceutical formulations of mouthwashes and to examine the antimicrobial activities of essential oils obtained from plants used traditionally in Turkey for oral infections. Materials and Methods: Essential oils were obtained from herbal drugs using water distillation with Clevenger apparatus. The antimicrobial capacities of mouthwash formulations containing a mixture of essential oils with proportions of 4.5% and 9.0% were examined using disc diffusion and microbroth dilutions. Results: The inhibition zone diameters were determined to vary between 7 and 59 mm. The static and cidal activity was generally 50% and greater than 50% when pure essential oil samples were applied on microorganism specimens. Formulation F2, which contained a mixture of essential oils with proportions of 4.5%, showed 6.25% minimum bactericidal effect on Staphylococcus aureus ATCC 25923, and 3.125% the minimum inhibitory concentration and minimum bactericidal concentration on all other microorganisms. The antimicrobial effect of pure essential oil samples applied on microorganisms was lower than of mouthwashes formulations; the antimicrobial effect of F2, which contained a mixture of essential oils with proportions of 4.5% was higher than formulation F1, which contained a mixture of essential oils with proportions of 9%. Conclusion: The results obtained by these methods allow us to conclude that the essential oils and the prepared F1 and F2 mouthwash formulations exerted activity against microorganisms affecting the oral cavity. The F2 formulation also had significant antimicrobial activity on the tested microorganisms.Öğe Is it safe to reuse dental implant healing abutments sterilized and serviced by dealers of dental implant manufacturers? An in vitro sterility analysis(Lippincott Williams and Wilkins, 2015) Çakan, Umut; Delilbaşı, Çağrı; Er, Sevda; Kıvanç, MerihPurpose: This study was undertaken to investigate the sterility of used healing abutments sterilized and serviced by dealers of dental implant manufacturers. Materials and Methods: Sixty used but sterilized healing abutments in sealed sterilization pouches were obtained from 6 manufacturers unaware of the study design and equally grouped from A to F. The sterilization pouches were examined for perforation. The driver slots and screw grooves of healing abutments were examined for calculus and scratches under a 35 LED magnifying lamp, without opening the pouches. Each abutment was immersed in brain heart infusion broth in test tubes and incubated. Results: Macroscopic observation of 57 healing abutments revealed dirty screw grooves (10.5%) and partially filled driver slots (5.2%). None of the group C, E, and F samples showed turbidity. Penicillium variabile was morphologically identified in 3 abutments of group A. Enterococcus faecalis and E faecium were detected in 1 abutment each of groups B and D, respectively. Conclusion: Reuse of healing abutments can be cost effective in dental practice. However, used abutments sterilized and serviced by dental implant dealers might be a source of cross-infection. They should therefore be cleaned and resterilized before reuse as a precaution.Öğe Synthesis and antifungal activity evaluation of New 1,2,4-triazole derivatives bearing salicylidene hydrazide moiety(Bentham Science Publ Ltd, 2016) Demirayak, Şeref; Kayagil, İsmail; Yurttaş, Leyla; Er, SevdaA series of new N'-(arylidene)-2-[(1-(4-nitrophenyl)-1H-1,2,4-triazol-3-yl)oxy]acetohydrazide derivatives (116) were prepared and tested for theira ntifungal activity against six plant pathogens, three human pathogens and two non-pathogen microorganisms. The target compounds were obtained with a multi-step reaction starting from 4-substitutedarylhydrazine derivatives and the structures of final compounds have been elucidated with IR, NMR, Mass spectroscopy data and elemental analysis results. The antifungal activity of the compounds was determined against eleven different Fusarium, Trichoderma, Aspergillus and Penicilliumspeciesby using microdilution method. Most of the target compounds showed excellent antifungal activity against a variety of fungal pathogens.Öğe Synthesis and antimicrobial activity evaluation of novel nitrofuranthiazoles(University of Istanbul, 2016) Yurttaş, Leyla; Şahin, Zafer; Er, Sevda; Demirayak, ŞerefIn this work, six novel 4-aryl-2-[2-((5-nitrofuran-2-yl)methylene)hydrazinyl] thiazole derivatives (2a-f) were synthesized starting from 5-nitro-2-furaldehyde diacetate by using Hantzsch thiazole synthesis. The antimicrobial activity of the title compounds were screened against five Gram positive bacteria B. cereus, E. faecalis, S. aureus, S. epidermidis, L. monocytogenes and two Gram negative bacteria E. coli and S. typhi. MIC and MBC were calculated and compared to standard drug nitrofurazone. Compounds bearing pyridine moiety (2d-e) exhibited significant antimicrobial activity which could be evaluated as new, potent antibacterial agents.Öğe Two different approaches for oral administration of voriconazole loaded formulations: Electrospun fibers versus beta-cyclodextrin complexes(MDPI, 2016) Siafaka, Panoraia I.; Okur Üstündağ, Neslihan; Mone, Mariza; Giannakopoulou, Spyridoula; Er, Sevda; Pavlidou, Eleni; Karavas, Evangelos; Bikiaris, Dimitrios N.In this work, a comparison between two different preparation methods for the improvement of dissolution rate of an antifungal agent is presented. Poly(epsilon-caprolactone) (PCL) electrospun fibers and beta-cyclodextrin (beta-CD) complexes, which were produced via an electrospinning process and an inclusion complexation method, respectively, were addressed for the treatment of fungal infections. Voriconazole (VRCZ) drug was selected as a model drug. PCL nanofibers were characterized on the basis of morphology while phase solubility studies for beta-CDs complexes were performed. Various concentrations (5, 10, 15 and 20 wt %) of VRCZ were loaded to PCL fibers and beta-CD inclusions to study the in vitro release profile as well as in vitro antifungal activity. The results clearly indicated that all formulations showed an improved VRCZ solubility and can inhibit fungi proliferation.
