Browsing by Author "Otlu, Baris"

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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-1232-2015
Our 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.
HEV seroprevalence in blood donors in Turkey by two commercial total anti-HEV Ab ELISA kits
(2019) Yasar, Osman; Karatayli, Ersin; Cengiz, Guniz; Kizilpinar, Mehtap; Yurdcu, Esra; Albayrak, Rabia; Guven, Aysel; Arslan, Onder; Karahan, Ceren; Otlu, Baris; Guducuoglu, Huseyin; Gokahmetoglu, Selma; Berk, Elife; Gitmisoglu, Ozlem; Sertoz, Ruchan; Yurdaydin, Cihan; Bozdayi, A. Mithat; Karatayli, Senem Ceren; 31403185
Previous hepatitis E virus (HEV) seroprevalence studies in Turkey have shown high variabilities, leading to conflicting results. We aimed to re-evaluate HEV seroprevalence among blood donors in Turkey using the Wantai (Beijing, China) and the Dia.Pro (Milan, Italy) total anti-HEV antibody (Ab) enzyme-linked immunosorbent assay (ELISA) kits and compare their performances and to investigate the presence of HEV RNA in blood donors. Serum total anti-HEV antibodies were determined in a total of 2011 volunteer blood donor samples collected from different regions of Turkey (807 from Ankara, 243 from Kayseri, 284 from Izmir, 200 from Malatya, 200 from Kahramanmaras, and 277 from Van). HEV RNA was evaluated by a real-time polymerase chain reaction in a total of 272 anti-HEV seropositive samples. The country-wide HEV seroprevalence was calculated as 11.5% (Dia.Pro) and 12.2% (Wantai) with seropositivity rates of 12.0%-12.5% in Ankara, 7.4%-8.2% in Kayseri, 14.5%-15.5% in Malatya, 8.1%-8.8% in Izmir, 15.0%-16.0% in Kahramanmaras, and 12.6%-13.4% in Van by Dia.Pro and Wantai kits, respectively. The lowest detectable Ab concentrations were 0.16 and 0.14 units/mL WHO, for the Dia.Pro and the Wantai assays, respectively, showing no significant difference between assays. HEV RNA was not detected in any of the anti-HEV seropositive samples. Compared with previous studies, HEV was shown to have a higher overall seroprevalence in Turkey. Despite its limitation, the current study represents the most comprehensive HEV seroprevalence study in Turkey performed with two different commercial ELISA assays with high sensitivities so far. Further investigation is required to determine HEV genotypes in Turkey.
HEV Seroprevalence in Blood Donors in Turkey: Comparison of Two Commercial Anti-HEV Total Ab ELISA Kit
(2019) Yasar, Osman; Cengiz, Guniz; Karatayli, Ersin; Kizilpinar, Mehtap; Yurdcu, Esra; Albayrak, Rabia; Arslan, Onder; Karahan, Zeynep Ceren; Otlu, Baris; Guven, Aysel; Guducuoglu, Huseyin; Gokahmetoglu, Selma; Berk, Elife; Gitmisoglu, Ozlem; Sertoz, Ruchan; Yurdaydin, Cihan; Mithat, Bozdayi; Karatayli, Senem Ceren
Molecular Epidemiological Analysis of Bacillus Pseudo-Outbreak due to Contaminated Culture Tubes Containing Stuart Medium
(2022) Asgin, Nergis; Kal-Cakmakliogullari, Elcin; Otlu, Baris; Ersoy, Omer F.; Celik, Betul; Basustaoglu, Ahmet; 35023676
Background: It is challenging to determine whether Bacillus species other than Bacillus anthracis cause infections. Pseudo and true outbreaks of Bacillus spp. have been noted. Here, we present a molecular analysis of a Bacillus spp. pseudo-outbreak caused by contaminated culture tubes containing Stuart medium. Methods: Between January and March 2015, a high percentage of Bacillus spp. was isolated from the wound samples of inpatients at the Karabuk University Hospital, and an outbreak was suspected. Environmental and staff nasal samples were cultured aerobically, and Bacillus spp. were isolated from some of them. However, the isolation of Bacillus spp. in throat cultures of outpatients suggested contamination caused by culture tubes containing Stuart medium. We examined two lots of culture tubes used in the hospital. Although the culture tubes' expiry date and storage conditions were suitable, Bacillus spp. grew in one of these lots. A total of 47 Bacillus spp. isolated during this period were identified, and the clonal relationship among the isolates was investigated by arbitrarily primed polymerase chain reaction. Results: Twenty-seven strains were identified as Bacillus megaterium and 20 as Bacillus firmus. Of the four strains isolated from the Stuart medium, two were identified as B. firmus and the other two were B. megaterium. Two B. firmus strains isolated from the Stuart medium and two B. firmus strains obtained from the coronary intensive care environmental samples were matched and clustered within the same genotype. We recalled all culture tubes containing Stuart medium. After another brand's culture tubes were distributed, no growth was observed. It was then understood that the pseudo-outbreak source was contaminated culture tubes containing Stuart medium. Conclusions: Microbiological controls of medical materials and equipment should be regularly checked to prevent outbreaks (true or pseudo).