Tıp Fakültesi / Faculty of Medicine

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

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Author: search.filters.author.Guclu, Aylin UskudarHas files: No

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    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-6196-2020
    Introduction. 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.
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    In vitro and in vivo evaluation of linezolid loaded electrospun PLGA and PLGA/PCL fiber mats for prophylaxis and treatment of MRSA induced prosthetic infections
    (2020) Boncu, Tugba Eren; Guclu, Aylin Uskudar; Catma, Mehmet Faruk; Savaser, Ayhan; Gokce, Aysun; Ozdemir, Nurten; 0000-0002-1872-028X; 31678530; AAU-6196-2020
    In this study, it was aimed to formulate linezolid loaded electrospun PLGA and PCL fiber mats doing controlled drug release, to be used in the treatment and prophylaxis of the prosthesis related infections. The effect of PLGA concentration, PLGA to PCL ratio and the amount of linezolid on the fiber and mat properties were examined. Fiber diameter has been shown to increase with increasing amount of PLGA and linezolid. Increase in PLGA amount resulted in reduced linezolid release, whereas increase in linezolid amount resulted in increased drug release. All PLGA fiber mats have shown to have favorable encapsulation efficiency (>= 73%) and mechanical properties. Encapsulation efficiency and the mechanical properties deteriorated with the addition of PCL to the formulations. PLGA fiber mats have shown a biphasic controlled release and in vitro antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), pattern up to one month. The formulation selected as the optimum has been evaluated in vivo on the infected rats, which had prosthetic implantation after bone fracture. Consequently, it has been demonstrated microbiologically and histopathologically that a more efficient therapy and prophylaxis have been achieved with a 37-fold lower dose of linezolid.
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    Prevalence and Quantity of Parvovirus B19 DNA Among Blood Donors from a Regional Blood Center in Turkey
    (2020) Guclu, Aylin Uskudar; Yilmaz, Soner; Baysallar, Mehmet; Avci, Ismail Yasar; 0000-0002-1872-028X; 32439492; AAU-6196-2020
    Objective: Parvovirus B19 causes a range of diseases and morbidity in humans and is transmissible by transfusion of blood, blood components and plasma derivatives. The objective of the study was to investigate the prevalence and quantity of B19 DNA among blood donors. Method: Totally 1053 samples were collected from March to July 2016 at a blood bank for detection of Parvovirus B19 DNA and serological status of blood donors. Testing of the presence of viral DNA was performed by a quantitative real-time PCR with a 101 copies/ml detection limit. All DNA positive and randomly selected 267 samples were tested for the presence of anti-B19 IgM and IgG by ELISA. Results: Age distribution of donors was between 18-64; mean age was 27 and median was 23. Among the 1053 samples, 5 (0.47%) had PB19 DNA. All PB19 DNA positive donations had both B19 IgM and IgG antibodies. The DNA level for positive donations were between 0.9 x 102 to 3.1 x 104 copies/ml. IgG and IgM were present in 59.9% (160/267) and 0,74% (2/267) respectively among the healthy donors without PB19 DNA. Conclusion: Detected DNA concentration was less than 105 copies/ml. The presence of IgM in low level PB19 DNA positive donors may indicate that there might be a risk in transmission of PB19 to particularly immunosuppressed recipients. The clinical follow-up of blood donation with low level of PB19DNA should be considered to answer the questions about blood safety.