Browsing by Author "Tollu, Gulsah"

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Biotyping and Antimicrobial Susceptibility of Enterococcus Faecalis and E. Faecium Isolated From Urine and Stool Samples
(Kowsar Publ, 2020) Tollu, Gulsah; Ekin, Ismail Hakki
Background: Enterococci are one of the opportunistic pathogenic microorganisms that can cause significant problems for human and animal health. Enterococcus faecium seems to be more resistant to antibiotics than E. faecalis. It is thought that pathogenic E. faecium can develop antibiotic resistance very quickly, and the ability to transfer this feature is considered to be an important health risk. Objectives: This study aimed to determine the prevalence, biotypes, and in vitro antimicrobial susceptibility of E. faecalis and E. faecium strains isolated from 267 routine urine and stool samples that were brought to the microbiology laboratory of Regional Training and Research Hospital of Van, with permission of the patients. Methods: In the present study, enterococci using species-specific primers to examine E. faecalis and E. faecium multiplex PCR technique was applied. Biotyping of the isolates was used to identify them as E. faecalis and E. faecium by molecular techniques, and antibiotic susceptibility of all samples was examined, as well. Results: The isolates were identified by multiplex PCR using species-specific primers for E. faecalis and E. faecium. Biotyping based on 13 biochemical tests showed that 72.5%, 12.5%, and 15% of E. faecalis strains were of biotypes I, II, and III, respectively, whereas E. faecium strains could be divided into biotype I (10%), biotype II (12.5%), biotype III (27.5%), and biotype IV (50%). Additionally, all E. faecalis strains were found to be susceptible to penicillin G and imipenem. On the other hand, 95% of the E. faecalis strains were found to be resistant to clindamycin, 77.5% to tetracycline and trimethoprim/sulfamethoxazole, 42.5% to erythromycin, 32.5% to gentamicin, and 17.5% to ciprofloxacin. Of E. faecium strains, 37.5% were found to be resistant to clindamycin, 32.5% to penicillin G, 27.5% to erythromycin and imipenem, 20% to ciprofloxacin, 17.5% to tetracycline and trimethoprim/sulfamethoxazole, 15% to gentamicin, and 5% to vancomycin. Conclusions: In conclusion, the identification of E. faecalis and E. faecium strains by PCR is reliable and faster than biochemical tests. Additionally, the results of antimicrobial susceptibility tests may provide important contributions to the clinical approach.
Investigation of Antibacterial Activity and Polyethersulfone (Pes) Membrane Usability of Delafossite-Type Cumno2 and Cumno2-Nh2 Nanostructures
(Springer, 2025) Yildirim, Rahel; Ozdemir, Sadin; Tollu, Gulsah; Gulcan, Mehmet; Filiz, Volkan; Dizge, Nadir
Membrane fouling is one of the most important issues in membrane studies and remains a current challenge. Therefore, developing composite membranes to reduce fouling is essential. In this study, delafossite-type CuMnO2 and CuMnO2-NH2 nanostructures were synthesized and characterized in detail using various instrumental tools, including SEM, SEM-Elemental Mapping, P-XRD, BET, and FTIR. The biological properties of CuMnO2 and CuMnO2-NH2 nanostructures, including antioxidant, antimicrobial, cell viability, antidiabetic activity, antibiofilm activity, and DNA fragmentation, were examined. Both materials exhibited good antioxidant, antimicrobial, and antibiofilm properties. The highest antioxidant activity for CuMnO2 was 75.93% at 100 mg/L, while the highest antioxidant activity for CuMnO2-NH2 was 92.35% at 100 mg/L. The most effective MIC value of 16 mg/L was obtained for CuMnO2 against Enterococcus hirae and Enterococcus faecalis. The highest amylase activity, at 165.2%, was observed at 100 mg/L for CuMnO2. Both CuMnO2 and CuMnO2-NH2 exhibited complete inhibition of microbial cell viability (100%) at 100 mg/L. Additionally, they demonstrated excellent biofilm inhibition activities against S. aureus and P. aureginosa. Furthermore, the use of polyethersulfone (PES) membranes coated with CuMnO2 and CuMnO2-NH2 compounds for the eradication of Escherichia coli was investigated, along with the antibacterial activities of the membrane surface and permeate.
Synthesis and Biological Properties of Benzyl 2-(oxy)benzoate Silicon Phthalocyanine
(Springer, 2024) Solgun, Derya Guengoerdue; Ozdemir, Sadin; Agirtas, Mehmet Salih; Tollu, Gulsah
Bis-benzyl 2-(oxy) benzoate substituted axially silicon phthalocyanine was synthesized by the reaction of silicon phthalocyanine dichloride and benzyl salicylate compounds. Characterization of the compound was done by FT-IR, 1H NMR, 13C NMR, UV-visible and Mass spectrum. Photochemical and photophysical properties of new silicon phthalocyanine (SiPc) was investigated. Biological properties of SiPc was carried out by several different parameters. The highest antioxidant ability of 73.18% was obtained at 100 mg/L concentration while the lowest antioxidant activity of 38.46% was obtained at 6.25 mg/L concentration. The antimicrobial effects of SiPc were investigated against different bacteria and microfungi. The results regarding the antimicrobial activity of this compound 3 showed that E. faecalis (ATCC 29,212) was the most sensitive microorganism to the tested compounds, while C. tropicalis was the most resistant microorganism. In addition, when the antimicrobial photodynamic treatment of SiPc was examined, a better activity was observed against all microorganisms. DNA fragmentation activity and microbial cell viability of compound 3 was investigated. SiPc showed excellent DNA nuclease activity and 99.96% inhibition of cell viability at 100 mg/L. The effect of compound 3 on antibiofilm activity fabricated by S. aureus and P. aureginosa was also measured and a good biofilm inhibition values of 86.51% and 75.24% was achieved at 50 mg/, respectively. In addition, when the antidiabetic effects of the compounds were examined, it showed an antidiabetic effect of 20.14% at 400 mg/L.