Tıp Fakültesi / Faculty of Medicine
Permanent URI for this collectionhttps://hdl.handle.net/11727/1403
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Item Comparative in Vitro Activities of Omadacycline, Eravacycline and Tigecycline Against Non-ESBL- Producing ESBL- Producing and Carbapenem- Resistant Isolates of K. Pneumoniae(2022) Mirza, Hasan Cenk; Guclu, Aylin Uskudar; Ceviz, Gizem Ince; Basustaoglu, Ahmet; 0000-0002-8853-3893; 0000-0002-1872-028X; 36301611; F-1232-2015; AAU-6196-2020Introduction. Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae and carbapenem-resistant Enterobacte-riaceae are characterized by the World Health Organization as pathogens for which new antibiotics are urgently needed. Oma-dacycline and eravacycline are two novel antibacterials within the tetracycline class.Gap Statement. There are limited data regarding the comparison of the activities of omadacycline, eravacycline and tigecycline against K. pneumoniae isolates with different antimicrobial susceptibility profiles.Aim. Our objective was to compare the in vitro activities of omadacycline, eravacycline and tigecycline against a collection of K. pneumoniae isolates, including non- ESBL-producing, ESBL-producing and carbapenem-resistant strains.Methodology. Ninety-four K. pneumoniae isolates, including 30 non- ESBL-producing, 30 ESBL-producing and 34 carbapenem-resistant (22 carrying blaOXA-48, 12 carrying blaNDM) strains were included in the study. ESBL and carbapenemase genes were detected by conventional PCR. Omadacycline, eravacycline and tigecycline MICs were determined by the gradient diffusion method and interpreted using US Food and Drug Administration (FDA)-defined breakpoints.Results. Overall, the percentage of tigecycline-susceptible strains (97.9 %) was higher than the percentage of omadacyline-susceptible (75.5 %) and eravacycline-susceptible (72.3 %) strains. The omadacycline and eravacycline susceptibility rates were 83.3 % among non- ESBL-producing isolates and 66.7 % among ESBL-producing isolates. The most common ESBL gene detected was blaCTX-M (90 %), followed by blaTEM (50 %) and blaSHV (50 %). The omadacycline and eravacycline susceptibility rate among isolates carrying blaTEM was 33.3 %, whereas it was 100 % among isolates that do not carry blaTEM. The omadacycline and eravacycline susceptibility rates among carbapenem-resistant isolates were 76.5 and 67.6 %, respectively. The omadacycline susceptibility rates among blaOXA-48-positive and blaNDM-positive isolates were 77.3 and 75.0 %, respectively. The eravacycline susceptibility rates among blaOXA-48-positive and blaNDM- positive isolates were 68.2 and 66.7 %, respectively. One carbapenem-resistant isolate was intermediate and one ESBL-producing isolate was resistant to tigecycline.Conclusion. Overall, tigecycline was the most active tetracycline against isolates. Omadacycline and eravacycline showed excellent activity against ESBL-producing K. pneumoniae isolates that do not carry blaTEM. Omadacycline showed reasonable activity against carbapenem-resistant K. pneumoniae isolates carrying blaOXA-48 or blaNDM.Item Clinical Strains of Chryseobacterium and Elizabethkingia spp. Isolated from Pediatric Patients in a University Hospital: Performance of MALDI-TOF MS-Based Identification, Antimicrobial Susceptibilities, and Baseline Patient Characteristics(2017) Mirza, Hasan Cenk; Tuncer, Ozlem; Olmez, Serpil; Sener, Burcin; Tugcu, Gokcen Dilsa; Ozcelik, Ugur; Gursoy, Nafia Canan; Otlu, Baris; Buyukcam, Ayse; Kara, Ates; Sancak, Banu; https://orcid.org/0000-0002-8853-3893; 29227188; F-1232-2015Our objective was to evaluate the performance of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) for identification of the Chryseobacterium and Elizabethkingia spp. isolated from pediatric patients at Hacettepe University Hospital using 16S rRNA gene sequencing as the gold standard and to determine the antimicrobial susceptibility patterns of the isolates and baseline characteristics of patients. All stored Chryseobacterium and Elizabethkingia spp. isolated from various clinical specimens (sputum, blood, and urine) of pediatric patients at Hacettepe University Hospital between 2012 and 2016 were included in this study. Minimum inhibitory concentrations of 10 antimicrobial agents were determined by Etest for all isolates. To determine the baseline characteristics of patients, medical records of all patients were retrospectively reviewed. In total, 18 isolates of Chryseobacterium spp. (16 C. indologenes, 2 C. gleum) and 5 isolates of Elizabethkingia spp. (3 E. meningoseptica, 2 E. anophelis) were identified by 16S rRNA sequencing. MALDI-TOF MS correctly identified 19 (82.6%) isolates to the species level. The quinolones (ciprofloxacin and levofloxacin), trimethoprim/sulfamethoxazole and piperacillin/tazobactam showed the highest spectrum of activity against the overall collection of isolates. Cystic fibrosis (CF) was the underlying disease in 81.8% of patients. To our knowledge, this study includes the largest number of Chryseobacterium spp. isolated from clinical specimens of pediatric patients in Turkey. In this study, we also report the first clinical isolate of E. anophelis in Turkey. Since, the majority of strains were isolated from patients with CF; larger, prospective clinical studies are needed to establish whether chryseobacteria could be considered as an emerging opportunistic pathogen in patients with CF.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.