Person: KARAHASAN, AYŞEGÜL
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KARAHASAN
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AYŞEGÜL
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Publication Open Access A possible role of Bacteroides fragilis enterotoxin in the aetiology of colorectal cancer(ELSEVIER SCI LTD, 2006-08) KARAHASAN, AYŞEGÜL; Toprak, N. Ulger; Yagci, A.; Gulluoglu, B. M.; Akin, M. L.; Demirkalem, P.; Celenk, T.; Soyletir, G.The prevalence of enterotoxigenic Bacteroides fragilis (ETBF) was investigated in stool specimens from 73 patients with colorectal cancer and from 59 control patients. Stool specimens were cultured on Bacteroides Bile Esculin agar and B. fragilis was identified by conventional methods. After DNA extraction, the enterotoxin gene (bft) was detected by PCR in 38% of the isolates from colorectal cancer patients, compared with 12% of the isolates from the control group (p 0.009). This is the first study demonstrating an increased prevalence of ETBF in colorectal cancer patients.Publication Metadata only The distribution of the bft alleles among enterotoxigenic Bacteroides fragilis strains from stool specimens and extraintestinal sites(ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD, 2006) KARAHASAN, AYŞEGÜL; Ulger, N; Rajendram, D; Yagci, A; Gharbia, S; Shah, HN; Gulluoglu, BM; Akin, LM; Demirkalem, P; Celenk, T; Soyletir, GEnterotoxigenic Bacteroides fragilis (ETBF) has been implicated in diarrhoeal illness in animals and humans. Recent data Suggest that ETBF is associated with flares of inflammatory bowel disease. Toxigenicity is attributed to expression of a toxin referred to as fragilysin, which stimulates fluid accumulation in ligated intestinal segments and alter the morphology or human intestinal cells. Three different isoforms or variants of the enterotoxin gene, designated bft-1, bft-2, and bft-3, have been identified. In this study we investigated the distribution of bft alleles among ETBF strains in stool specimens from patients with colon cancer (n:31), the control patients (n: 8) and extraintestinal sources (n: 15). We used restriction fragment length polymorphism analysis of the PCR-amplified enterotoxin gene and sequencing the PCR-product to detect the isoforms of bft gene. Among the stool strains, bft-1 was found to be more common than bft-2; as it was detected 27 of 31 strains from colon cancer patients and 7 of 8 control strains. The bft-1 isoform was also found in almost all isolates from extraintestinal sites. No bft-3 subtype was detected among all tested strains. (C) 2005 Elsevier Ltd. All rights reserved.Publication Metadata only Sağlıklı çocukların orafarenksinde kolonize olan bakteriyel patojenlerin antimikrobiyal duyarlılıkları(Ankara Üniversitesi Tıp Fakültesi Yayınları, 2000-10-11) KARAHASAN, AYŞEGÜL; İLKİ, ZEYNEP ARZU; ÜLGER, NURVER; SÖYLEDİR, GÜNER; Karahasan A., İlki Z. A., Ülger N., Söyledir G.; Cengiz, A. Tevfik; Erdem, Birsel; Dolapçı, G. İştar; Tekeli, F. AlperPublication Open Access Evaluation of BioFire Filmarray panel for respiratory pathogens: A demographic and clinical analysis in Istanbul, Turkey(2023-05-01) KARAHASAN, AYŞEGÜL; ÇİMŞİT, NURİ ÇAGATAY; Karahasan A., Çimşit N. Ç.We aimed to analyze the distribution of respiratory pathogens(RP) detected by a multiplex PCR-based method (BioFire Diagnostics, USA) among patients with suspected respiratory tract infections (RTI) and to evaluate the demographic, clinical and radiological characteristics of infected individuals . RP were detected in 1621/6376 (25.4%) of the samples in the years 2018-2020. Rhinovirus/enterovirus (RV/EV) were the most commonly detected pathogens (38.1%) followed by influenza A and B viruses (21%) and parainfluenza virus (PIV) (9.5%). Single pathogen was detected in 1361 (84%) and multi pathogens in 260 (16%) of 1621 samples. At least one comorbidity was present in 379 (30.5%) of the patients. Fever was the most common sign followed by cough and dyspnea. Thorax CT was present in 426 of 1243 RP positive patients (34.3%). Any radiological findings was found significantly related for a specific pathogen. No medication was given to 52.9% whereas antibiotics in 35.7% and antivirals in 3.8% of the patients. Film Array panel as a multiplex PCR test is not used rationally in our hospital and results were not dramatically improve management of RTI. A better communication between clinician and microbiologist is required for efficient use of laboratory and rational use of antimicrobials.Publication Metadata only Polimeraz zincir reaksiyonu temelli tiplendirme yöntemleri: AP-PCR, ERIC-PCR, REP-PCR, PCR-RFLP(Nobel Yayın Dağıtım, 2022-11-01) KARAHASAN, AYŞEGÜL; Karahasan A.; Otlu, Barış; Durmaz, RızaPublication Metadata only Incidence of MIS-C and the Comorbidity Scores in Pediatric COVID-19 Cases(2021) KARAHASAN, AYŞEGÜL; Ergenc, Zeynep; Kepenekli, Eda; Çetin, Ece; Ersoy, Ayşenur; Korkmaz, Billur; Selçik, Raziye; Sarınoglu, Rabia Can; Karahasan, AysegülBACKGROUND: We aimed to determine the incidence of multisystem ınflammatory syndrome in children (MIS-C) in pediatric coronavirus disease 2019 (COVID-19) cases and to define the relationships between the need for hospitalization, the development of MIS-C, and Charlson (CCI) and Pediatric comorbidity index (PCI) scores. METHODS: All pediatric COVID-19 cases between March 25, 2020, and December 28, 2020, in the Marmara University Pendik Training and Research Hospital were enrolled. Patients who needed hospitalization were determined. Hospital records were reexamined to identify those diagnosed as having MIS-C. CCI and PCI were used to validate the comorbidity status. RESULTS: Among 2055 pediatric COVID-19 cases, 1340 were included in the study. Two hundred thirteen patients (15.9%) had at least one comorbidity. All the patients or their parents were interviewed about the need for hospitalization, except for the acute period. Six patients had MIS-C, which corresponds to a MIS-C incidence of 0.4%. The need for hospitalization increased in the patients with comorbidities (p<0.05). No correlation was found between the comorbidity scores and the development of MIS-C. The need for hospitalization increased in the patients with CCI scores of ≥2 and PCI scores of ≥4 (p<0.05). CONCLUSIONS: Our study is the first to examine the incidence of MIS-C, which was 0.4%, by long-term follow-up of pediatric COVID-19 cases and to demonstrate that the CCI and PCI can be used to predict the need for hospitalization and prognosis of pediatric patients with COVID-19.Publication Metadata only İdrar kültürlerinde kontaminasyon oranları düşürülebilir mi(2023-05-01) KARAHASAN, AYŞEGÜL; Karahasan A.Publication Metadata only Predictors of eradication failure at first isolation of MRSA in cystic fibrosis patients(EUROPEAN RESPIRATORY SOC JOURNALS LTD, 2020) KARAHASAN, AYŞEGÜL; Mursaloglu, Huseyin Hakan; Akin, Can; Yilmaz, Cansu; Ergenekon, Pinar; Gokdemir, Yasemin; Eralp, Ela Erdem; Karakoc, Fazilet; Karahasan, Aysegul; Karadag, BulentPublication Metadata only Detection of anti-tetanus antibodies in Turkish population(ROYAL SOC MEDICINE PRESS LTD, 1999) KARAHASAN, AYŞEGÜL; Soyletir, G; Yagci, A; Topkaya, A; Ciragil, PPublication Open Access Phenolic compounds affect production of pyocyanin, swarming motility and biofilm formation of Pseudomonas aeruginosa(WOLTERS KLUWER MEDKNOW PUBLICATIONS, 2016-08) KARAHASAN, AYŞEGÜL; Ugurlu, Aylin; Yagci, Aysegul Karahasan; Ulusoy, Seyhan; Aksu, Burak; Bosgelmez-Tinaz, GulgunObjective: To investigate the effects of plant-derived phenolic compounds (i.e. caffeic acid, cinnamic acid, ferulic acid and vanillic acid) on the production of quorum sensing regulated virulence factors such as pyocyanin, biofilm formation and swarming motility of Pseudomonas aeruginosa (P. aeruginosa) isolates. Methods: Fourteen clinical P. aeruginosa isolates obtained from urine samples and P. aeruginosa PA01 strain were included in the study. The antibacterial effects of phenolic compounds were screened by well diffusion assay. Pyocyanin and biofilm activity were measured from culture supernatants and the absorbance values were measured using a spectrophotometer. Swarming plates supplemented with phenolic acids were point inoculated with P. aeruginosa strains and the ability to swarm was determined by measuring the distance of swarming from the central inoculation site. Results: Tested phenolic compounds reduced the production of pyocyanin and biofilm formation without affecting growth compared to untreated cultures. Moreover, these compounds blocked about 50% of biofilm production and swarming motility in P. aeruginosa isolates. Conclusions: We may suggest that if swarming and consecutive biofilm formation could be inhibited by the natural products as shown in our study, the bacteria could not attach to the surfaces and produce chronic infections. Antimicrobials and natural products could be combined and the dosage of antimicrobials could be reduced to overcome antimicrobial resistance and drug side effects.