Scopus İndeksli Yayınlar Koleksiyonu
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Item Evaluation of a Commercial Broth Microdilution Panel for Colistin Susceptibility Testing of Clinical Isolates of Escherichia coli and Klebsiella pneumoniae(2021) Mirza, Hasan C.; Bicakcigil, Asiye; Liste, Umran; Sancak, Banu; 0000-0002-8853-3893; 33978373; F-1232-2015Background: Colistin is among the last resort antibiotics for the treatment of infections caused by multidrug-resistant Gram-negative pathogens. Antimicrobial susceptibility testing of colistin is challenging due to its physicochemical properties. Broth microdilution (BMD) is the recommended method for colistin susceptibility testing. However BMD is not practical for clinical microbiology laboratories as manual preparation of BMD plates is time-consuming and labor intensive. Recently, some more user-friendly BMD products with commercial panels have become available. Our objective was to evaluate the performance of a commercial broth microdilution (BMD) product [Sensititre (Thermo Fisher Scientific)] for colistin MIC determination by comparison with reference BMD method using a collection of E. coli and K. pneumoniae isolates. Methods: A total of 323 unique patient isolates (102 E. coli, 221 K. pneumoniae) were included in the study. Isolates were stored at -70 degrees C and subcultured twice on sheep blood agar before testing. Colistin MICs of the isolates were determined using Sensititre (a premade BMD product with dried antibiotics) and an 'in-house prepared BMD panel prepared in accordance with CLSI guidelines' (reference method). MIC determination with Sensititre was performed according to manufacturer's instructions. The reference method was performed using untreated 96-well sterile polystyrene plates. Colistin MIC results were interpreted according to EUCAST breakpoints (susceptible, <= 2 mg/L; resistant, > 2 mg/L). Results: Overall susceptibility rate of isolates to colistin by reference BMD was 75.9%. Overall categorical agreement (CA), essential agreement (EA), very major error (VME), and major error (ME) rates for Sensititre were 98.5%, 72.5%, 3.8%, and 0.8%, respectively. The CA and EA between Sensititre and reference BMD for the isolates with reference colistin MICs close to the susceptibility breakpoint (2 - 8 mg/L) was 94.2% and 48.1%, respectively. Sensititre yielded a VME rate of 15% and ME rate of 0%, respectively, for this subset of isolates. Conclusions: In conclusion, Sensititre showed high CA but low EA with reference BMD for entire collection of isolates. The VME rate was just slightly above 3% and ME rate was acceptable. The rates of CA and EA were decreased and the rate of VME was increased when a subset consisting of more challenging isolates was used.Item Risk Factors for Urinary Tract Infection After Kidney Transplant: A Retrospective Analysis(2020) Tekkarimaz, Nihan; Ozelsancak, Ruya; Micozkadioglu, Hasan; Caliskan, Kenan; Demiroglu, Yusuf Ziya; Arslan, Ayse Hande; H, Mehmet; 0000-0001-5142-5672; 0000-0001-7631-7395; 0000-0002-0788-8319; 0000-0002-8767-5021; 0000-0002-3462-7632; 31424358; AAE-7608-2021; AAD-9088-2021; AAD-5716-2021; AAJ-7201-2021; AAJ-8097-2021Objectives: Urinary tract infections are the most common type of infections in kidney transplant recipients. They are also important factors for increased morbidity and mortality. The aims of this study were to evaluate the number of urinary tract infections, to identify possible donor/receiver-based risk factors, and to evaluate the impact of these infections on graft function. Materials and Methods: Medical records of patients who had undergone kidney transplant between 2010 and 2017 were retrospectively analyzed. Results: Our study included 145 patients (49 women [33.8%] and 96 men [66.2%]), with mean age of 35.2 +/- 12.4 years. There were 105 episodes of urinary tract infections in 55 of 145 patients (37.9%) during the first year after transplant. Female sex (P = .001), glomerulonephritis as primary kidney disease (P = .04), pretransplant diabetes (P = .05), and presence of ureteral stent (P = .03) were significant risk factors for the development of urinary tract infections. The most frequent pathogens identified were Escherichia coli and Klebsiella pneumoniae. Mean glomerular filtration rate at 12 months was significantly lower in patients with urinary tract infection than in patients without infection (80 +/- 25 vs 68 +/- 28 mL/min; P = .006). Conclusions: In kidney transplant recipients, urinary tract infections are common complications and have negative outcomes on graft function. These infections remain an important disease that requires frequent investigations and new ways of approach for prevention.Item Comparison of Antimicrobial Susceptibilities of Escherichia coli Isolated From Urinary Cultures of Different Patient Groups: A University Hospital Experience(2020) Mirza, Hasan Cenk; Sancak, Banu; F-1232-2015Objective: Our objective was to investigate the antimicrobial susceptibilities of Escherichia coli isolated from urinary cultures in Central Laboratory of Hacettepe University Faculty of Medicine Hospital and to examine the differences between antimicrobial susceptibilities of E. coli isolated from different patient groups. Methods: E. coli isolated from urinary cultures between January 1, 2017 and April 30, 2018 were included in our study. Automated systems, i.e. VITEK (R) 2 Compact (bioMerieux, Marcy l'Etoile, France) and BD Phoenix (Becton Dickinson, Sparks, MD, USA) and disk diffusion test were used for the determination of antimicrobial susceptibilities. The patients from whom the bacteria were isolated were divided into groups according to age (<18 years, 18-64 years, and >64 years), gender and patient care (outpatients/inpatients). Results: The highest susceptibility rates were observed for carbapenems (>99%), fosfomycin (98.5%), nitrofurantoin (98.3%) and amikacin (94.2%), whereas the highest resistance rates were observed for ampicillin (61.3%) and amoxicillin-clavulanate (37.5-45.7%). Antimicrobial resistance rates of isolates from patients aged 65 years and over were higher than those of patients in other age groups, with the exception of piperacillintazobactam, amikacin and ertapenem. The resistance rates of isolates belonging to male patients were higher than those belonging to female patients for all antimicrobials. Also, the resistance rates of isolates belonging to inpatients were higher than those belonging to outpatients for all antimicrobials. When the rates of extended-spectrum beta-lactamase (ESBL)-producing E. coli from different age groups were compared, the highest rate (34.2%) was observed among the isolates from patients aged 65 years and over. The rates of ESBL-producing E. coli from males (33.9%) and inpatients (36.3%) were higher than those from females (23.8%) and outpatients (23.3%), respectively. Conclusions: Antimicrobial susceptibilities of E. coli isolates may vary among different patient groups. Demographic features of patients may guide for selecting the antimicrobials for empiric treatment of urinary tract infections.Item Bacterial detection using bacteriophages and gold nanorods by following time-dependent changes in Raman spectral signals(2018) Moghtader, F.; Tomak, A.; Zareie, H.M.; Piskin, E.; 29583029This study attemps to develop bacterial detection strategies using bacteriophages and gold nanorods (GNRs) by Raman spectral analysis. Escherichia coli was selected as the target and its specific phage was used as the bioprobe. Target bacteria and phages were propagated/purified by traditional techniques. GNRs were synthesized by using hexadecyltrimethyl ammonium bromide (CTAB) as stabilizer. A two-step detection strategy was applied: Firstly, the target bacteria were interacted with GNRs in suspensions, and then they were dropped onto silica substrates for detection. It was possible to obtain clear surface-enchanced Raman spectroscopy (SERS) peaks of the target bacteria, even without using phages. In the second step, the phage nanoemulsions were droped onto the bacterial–GNRs complexes on those surfaces and time-dependent changes in the Raman spectra were monitored at different time intervals upto 40 min. These results demonstrated that how one can apply phages with plasmonic nanoparticles for detection of pathogenic bacteria very effectively in a quite simple test. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.