Tıp Fakültesi / Faculty of Medicine

Permanent URI for this collectionhttps://hdl.handle.net/11727/1403

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Author: search.filters.author.Mirza, Hasan Cenksearch.filters.applied.f.language: search.filters.language.tur

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    In vitro Activity of Delafloxacin against Methicillin-Resistant Staphylococcus aureus Isolated from Various Clinical Specimens
    (2021) Mirza, Hasan Cenk; Basustaoglu, Ahmet; Yanik Yalcin, Tugba; 0000-0002-8853-3893; F-1232-2015
    Introduction: Delafloxacin is a novel fluoroquinolone which has anionic and weak acid character at neutral pH. Activity of delafloxacin is reported to be increased in acidic environments. Many infections are characterized by acidic pH. Staphylococcus aureus is a microorganism which can survive and multiply in mildly acidic environments. The aim of this study was to compare the activity of delafloxacin and other fluoroquinolones (ciprofloxacin, levofloxacin, moxifloxacin) against MRSA isolates at neutral (7.4) and acidic (5.5) pH. Materials and Methods: A total of 51 MRSA isolated from various clinical specimens were included in the study. Disk diffusion method was used for antimicrobial susceptibility testing. The pH of Mueller Hinton Agar was adjusted to 7.4 or 5.5, and used as the medium for antimicrobial susceptibility testing. EUCAST breakpoints were used for ciprofloxacin, levofloxacin and moxifloxacin. FDA breakpoints were used for delafloxacin. Results: The most active fluoroquinolones against MRSA isolates at neutral pH were delafloxacin and moxifloxacin. Delafloxacin and moxifloxacin susceptibility rates of isolates were same (82.4%) at neutral pH. Of the isolates, 9.8% and 17.6% were resistant to delafloxacin and moxifloxacin, respectively. Four moxifloxacin-resistant isolates were categorized as intermediate to delafloxacin. Of the isolates, 76.5% and 78.4% were 'I - susceptible, increased exposure' to ciprofloxacin and levofloxacin, respectively. Of the isolates, 23.5% and 21.6% were resistant to ciprofloxacin and levofloxacin, respectively. At acidic pH; ciprofloxacin, levofloxacin and moxifloxacin susceptibility rates of isolates were not changed. However, all delafloxacin resistant/intermediate isolates at neutral pH became susceptible to delafloxacin at acidic pH. Conclusion: Delafloxacin was the most active fluoroquinolone against MRSA isolates at acidic pH. Based on our findings, delafloxacin may represent a treatment option for MRSA infections characterized by low pH.
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    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-1232-2015
    Objective: 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.