Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/11727/4809
Browse
4 results
Search Results
Item Investigation of anti-cholinesterase and anti-amyloidogenic activities of beta-lactam antibiotics(2022) Ozer, Eda Ozturan; Mirza, Hasan Cenk; Tan, Oya Unsal; Turkoglu, Suna; 0000-0002-8853-3893; 0000-0003-4805-1918; F-1232-2015; AAJ-2243-2021Objectives: Neuroinflammation is an important factor in the pathogenesis of neurodegenerative disesases. The following study aimed to clarify the effects of beta-lactam antibiotics to the cholinergic system, on acetylcholinesterase (AChE), butyrylcholinesterase (BuChE) activities, considering the structural differences of antibiotics, to evaluate the underlying mechanism of effects provided by protein-antibiotic interactions, and to clarify possible effects of the antibiotics on the aggregation of A beta-peptides. Methods: The inhibition/activation mechanisms for each antibiotic were examined kinetically by Ellman method. Destabilization effects of them on amyloid peptide fibrillation were examined and protein-ligand interactions were evaluated with most potent antibiotics by molecular docking studies. Results: The most powerful inhibitions were detected by the inhibition studies of AChE with ceftazidime (CAZ) and BuChE with amoxicillin (AMX). CAZ was exhibited dose-related dual effect on AChE activity. CAZ was actually the dose-related modifier of AChE. At higher concentrations, CAZ was a nonessential activator of AChE. Molecular docking studies have been confirmed by kinetic studies. Interested beta-lactam antibiotics did not prevent fibrillation rate as rifampicin. Conclusion: Inhibition/activation behaviours of studied beta-lactam antibiotics on both cholinesterases may suggest that cholinergic transmission is one of the crucially important components of the beta-lactam antibiotics-induced central nervous system adverse reactions.Item Comparison of in vitro activities of plazomicin and other aminoglycosides against clinical isolates of Klebsiella pneumoniae and Escherichia coli(2021) Ince, Gizem; Mirza, Hasan Cenk; Guclu, Aylin Uskudar; Gumus, Hale; Erol, Cigdem; Basustaoglu, Ahmet; 0000-0001-9071-9606; 0000-0002-1872-028X; 0000-0002-2535-2534; 0000-0002-8853-3893; 34499728; AAJ-2108-2021; AAU-6196-2020; AAJ-1219-2021; F-1232-2015Objectives: To compare the in vitro activity of plazomicin and two older aminoglycosides (gentamicin and amikacin) against 180 isolates of Escherichia coli and Klebsiella pneumoniae, including subsets of 60 non-ESBL-producing, 60 ESBL-producing and 60 carbapenem-resistant (46 carrying bla(OXA-48), 11 carrying bla(NDM) and 3 carrying bla(OXA-48) and bla(NDM)) strains. Methods: MICs of plazomicin, gentamicin and amikacin were determined by a gradient diffusion method. Gentamicin and amikacin MICs were interpreted according to CLSI criteria and EUCAST breakpoint tables. Plazomicin MICs were interpreted using FDA-defined breakpoints. Results: All non-ESBL-producing and ESBL-producing isolates were susceptible to plazomicin. The plazomicin susceptibility rate (71.7%) in carbapenem-resistant isolates was significantly higher than those observed for gentamicin (45%) and amikacin (56.7% and 51.7% according to CLSI and EUCAST breakpoints, respectively). Gentamicin, amikacin and plazomicin susceptibility rates (35.6% for gentamicin; 44.4% and 37.8% for amikacin according to CLSI and EUCAST breakpoints, respectively; 64.4% for plazomicin) in carbapenem-resistant K. pneumoniae were significantly lower than those observed for carbapenem-resistant E. coli isolates (73.3% for gentamicin; 93.3% for amikacin and plazomicin). Gentamicin, amikacin and plazomicin susceptibility rates for bla(NDM)-positive isolates were lower than those observed for bla(OXA-48)-positive isolates, but differences were not statistically significant. Among the isolates that were non-susceptible to both gentamicin and amikacin, the plazomicin susceptibility rate was less than 30%. Conclusions: Although plazomicin showed excellent in vitro activity against carbapenem-susceptible isolates, the plazomicin resistance rate increased to 35.6% among carbapenem-resistant K. pneumoniae and further increased to 45.5% among bla(NDM)-positive isolates.Item In vitro activity of ceftolozane-tazobactam and ceftazidime-avibactam against clinical isolates of meropenem-non-susceptible Pseudomonas aeruginosa: A two-centre study(2020) Mirza, Hasan Cenk; Hortac, Elvan; Kocak, Aylin Altay; Demirkaya, M. Hamiyet; Yayla, Buket; Guclu, Aylin Uskudar; Bustaoglu, Ahmet; 0000-0002-1872-028X; 0000-0002-8853-3893; 0000-0002-0451-0142; 0000-0002-4335-6897; 31568882; AAU-6196-2020; F-1232-2015; AAI-8012-2021Objectives: This study aimed to compare the activity of ceftazidime-avibactam (C/A), ceftolozane-tazobactam (C/T) and three anti-pseudomonal beta-lactams (piperacillin-tazobactam, ceftazidime and cefepime) against a collection of meropenem-non-susceptible Pseudomonas aeruginosa (P. aeruginosa) clinical isolates recovered from two centres in Turkey. Methods: A total of 102 unique patient isolates of meropenem-non-susceptible P. aeruginosa were included in the study. MICs of antimicrobials were determined by the gradient diffusion method. Results: Overall susceptibility rates for C/A and C/T were 83.3% and 82.4%, respectively. Both C/A and C/T had better activity than any one of the three anti-pseudomonal beta-lactams. According to the MIC50 values, C/T was the most potent agent against isolates. Although the susceptibility rates of isolates to C/T and C/A were similar, C/T (MIC50, 1 mg/mL) was four-fold more potent than C/A (MIC50, 4 mg/mL). The MIC50 values of C/A and C/T for the isolates that were non-susceptible to three beta-lactams were significantly higher than those for isolates that were non-susceptible to zero, one or two beta-lactams. Also, the C/A MIC50 value for the isolates that were non-susceptible to two beta-lactams was higher than that for isolates which were non-susceptible to one beta-lactam. Conclusions: C/A and C/T showed good activity against meropenem-non-susceptible P. aeruginosa isolates. However, resistance to these agents was not uncommon among these isolates. The overall beta-lactam susceptibility profile of isolates seems to have an effect on the probability of susceptibility to C/A and C/T. Antimicrobial susceptibility testing should be performed for C/A and C/T if these agents are considered for treatment of infections caused by meropenem-non-susceptible P. aeruginosa. (C) 2019 International Society for Antimicrobial Chemotherapy. Published by Elsevier Ltd.Item Prevention of Candida biofilm formation over polystyrene by plasma polymerization technique(2020) Kaleli-Can, Gizem; Hortac-Istar, Elvan; Ozguzar, Hatice Ferda; Mutlu, Mehmet; Mirza, Hasan Cenk; Basustaoglu, Ahmet; Gocmen, Julide Sedef; 0000-0002-8853-3893; 0000-0002-2571-0637; F-1232-2015; AAI-8926-2021This work investigates the antifungal effect of plasma polymer films produced by low-pressure RF-generated plasma system using acrylic acid, 2-hydroxyethyl methacrylate, and diethyl phosphite (DEP). Unmodified and plasma-modified polystyrene (PS) microplate wells were tested by 30 biofilm-positive Candida spp. isolated from blood samples and two control strains using a quantitative plaque assay method. Regardless of the precursors and plasma parameters, biofilm formation was inhibited for all plasma-modified microplate wells. The most significant anti-biofilm effect was observed on PS modified by DEP at 90 W plasma power with the inhibition of all Candida species' biofilm formation.