Browsing by Author "Hosgor-Limoncu, M"

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    Investigation of glycopeptid resistance in methicillin resistant staphylococcal isolates
    Hosgor-Limoncu, M; Ermertcan, S; Tasli, H; Kurutepe, S
    The emergence of Staphylococcus aureus strains with intermediate resistance (VISA) and heterogen resistance (hVISA) to vancomycin leads to the occurence of severe therapeutic problems. The aim of this study was to investigate the vancomycin resistance in methicillin resistant S.aureus (MRSA) and coagulase-negative staphylococci (MRCoNS) isolated from clinical samples in Bacteriology Laboratory of Microbiology and Clinical Microbiology Department of Celal Bayar University Faculty of Medicine, Manisa (located in western Anatolia, Turkey). A total of 120 staphyloccoccal strains (92 MRSA and 28 MRCoNS) isolated from different clinical specimens (tracheal aspirate, blood, abscess, wound swabs, sputum, catheter tips, etc) between the period of June 2005 to December 2006 were included to the study. Vancomycin resistance were determined by agar screening method using brain hearth infusion agar plates containing 6 mu g/mL vancomycin. Standard E-test and macro E-test methods were performed for 17 (14%) staphylococcal strains (10 MRSA and 7 MRCoNS) which had grown in agar screening plates. Vancomycin and teicoplanin minimal inhibitory concentration (MIC) ranges of those strains were found as 1.5-4 mu g/mL and 2-4 mu g/mL, respectively, by standard E-test method. In our study, no VISA and hVISA isolates were detected when MIC value of >= 8 mu g/mL for vancomycin and teicoplanin, or >= 22 mu g/mL for teicoplanin only were accepted as the criteria for hVISA determination. Agar screening method which is preferably used in routine laboratories for practical and economical reasons, lower sensitivity and specificity than E-test. It can be concluded that, since agar screening method is not reliable for the detection of vancomycin resistance, further multi-center studies with the use of standard methods are needed in order to clarify the vancomycin resistance patterns of staphylococci in our country.
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    Synthesis and antileishmanial activity of novel pyridinium-hydrazone derivatives
    Alptuzun, V; Cakiroglu, G; Limoncu, ME; Erac, B; Hosgor-Limoncu, M; Erciyas, E
    A series of substituted phenylethylidenehydrazinylpyridinium derivatives bearing methyl, ethyl, propyl, and propylphenyl groups on the pyridinium nitrogen were synthesized and evaluated for in vitro antileishmanial activity against Leishmania tropica by using the microdilution method. Among the tested compounds, 3d, 5c, 3b, and 3c were found to be the most active derivatives against the promastigotes of L. tropica (IC50 values are 6.90, 9.92, 11.69 and 12.03 mu M, respectively) and to be more active than reference drug meglumine antimonaite (glucantime) (IC50 value: 20.49 mu M). The derivatives investigated in this study may have the potential to be lead compound against leishmanial infection.
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    Gamma scintigraphy and biodistribution of 99mTc-cefotaxime sodium in preclinical models of bacterial infection and sterile inflammation
    Ilem-Ozdemir, D; Asikoglu, M; Ozkilic, H; Yilmaz, F; Hosgor-Limoncu, M; Ayhan, S
    Tc-99m-cefotaxime sodium (Tc-99m-CEF) was developed and standardized under varying conditions of reducing and antioxidant agent concentration, pH, radioactivity dose, and reducing agent type. Labeling studies were performed by changing the selected parameters one by one, and optimum labeling conditions were determined. After observing the conditions for maximum labeling efficiency and stability, lyophilized freeze dry kits were prepared accordingly. Simple method for radiolabeling of CEF with Tc-99m has been developed and standardized. Labeling efficiency of Tc-99m-CEF was assessed by both radio thin-layer chromatography and radio high-performance liquid chromatography and found higher than 90%. The labeled compound was found to be stable in saline and human serum up to 24h. Two different freeze dry kits were developed and evaluated. Based on the data obtained from this study, both products were stable for 6months with high labeling efficiency. The prepared cold kit was found sterile and pyrogen free. The bacterial infection and sterile inflammation imaging capacity of Tc-99m-CEF was evaluated. Based on the in vivo studies, Tc-99m-CEF has higher uptake in infected and inflamed thigh muscle than healthy thigh muscle.
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    99mTc-Doxycycline hyclate: a new radiolabeled antibiotic for bacterial infection imaging
    Ilem-Özdemir, D; Asikoglu, M; Ozkilic, H; Yilmaz, F; Hosgor-Limoncu, M; Ayhan, S
    Radiolabeled antibiotics are promising radiopharmaceuticals for the precise diagnosis and detection of infectious lesions. Doxycycline Hyclate (DOX) was chosen to investigate new Tc-99m-labeled antibacterial agent. Ready to use freeze dry kits were formulated with optimum labeling conditions. Human serum stability, sterility, and pyrogenicity of kits were estimated, and gamma scintigraphy, in vivo biodistribution, and histopathological studies with bacterial infected rats were performed. DOX were successfully labeled by Tc-99m with high radiochemical purity, and the labeled compound was stable in human serum. Kits were sterile, pyrogen-free, and stable up to 6months. Static images depicted rapid distribution throughout the body and high uptake in bacterial infected thigh muscle. The uptake ratios of radiopharmaceuticals in infected thigh muscle were found above 2 up to 5h. Five hours after injection, the rats were sacrificed, and biodistribution was determined. Samples of bacterial infected muscle, healthy muscle, blood, liver, spleen, lung, kidney, stomach, intestine, urine and heart were weighed, and the radioactivity was measured by using a gamma counter. The %ID/g of Tc-99m-DOX was found 0.230.06 for infected thigh muscle. According to the imaging, biodistribution, and histopathological studies, the promising characteristics of Tc-99m-DOX make the new radiopharmaceutical valuable to examine for future studies. Copyright (c) 2013 John Wiley & Sons, Ltd.