Person:
KORTEN, VOLKAN

Profile Picture

Email Address

Birth Date

Research Projects

Organizational Units

OrgUnit Logo
Organizational Unit

Job Title

Last Name

KORTEN

First Name

VOLKAN

Name

Filters

2020 - 202323
Reset filters

Settings

Start date: 2020 × Has files: true ×

Search Results

Now showing 1 - 10 of 23
  • Thumbnail Image
    PublicationOpen Access
    A rare Case of otitis media-associated polymicrobial anaerobic meningitis and brain abscess
    (2021-12-01) ERTÜRK ŞENGEL, BUKET; TİGEN, ELİF; OLUÇ, YUSUF; ÜLGER, NURVER; KORTEN, VOLKAN; ERTÜRK ŞENGEL B., TİGEN E., YILDIZ F., OLUÇ Y., ÜLGER N., KORTEN V.
    Otitis media-associated complications are widespread when it is not treated with appropriate antimicrobial treatment. Meningitis and brain abscess are the most reported intracranial complications of otitis media, usually caused by the direct spread of organisms from the contagious site. While anaerobic microorganisms are well-known in brain abscesses, they are not common in meningitis. When the clinical history and pathogenesis of otitis mediaassociated meningitis are combined, special methods to identify and cover anaerobic pathogens should be considered
  • Thumbnail Image
    PublicationOpen Access
    An outbreak investigation of Burkholderia cepacia infections related with contaminated chlorhexidine mouthwash solution in a tertiary care center in Turkey
    (BMC, 2021-12) GÜL, FETHİ; Bilgin, Huseyin; Gelmez, Gulsen Altinkanat; Bayrakdar, Fatma; Sayin, Elvan; Gul, Fethi; Pazar, Nazli; Culha, Gulcan; Yildiz, Serap Suzuk; Cinel, Ismail; Korten, Volkan
    Background: We report a nosocomial outbreak caused by Burkholderia cepacia that occurred among six patients admitted in the medical and surgical intensive care unit between 04 March 2019 and 02 April 2019 in Istanbul, Turkey. Methods: The outbreak investigation was launched on 11 March 2019 five days after the detection of B. cepacia in four different patients. We defined potential reservoirs and started environmental screening. We sampled the liquid solutions used in patient care activities. Pulse-field gel electrophoresis (PFGE) was performed to determine the genetic relatedness of environmental and patient samples. Results: Burkholderia cepacia was isolated in tracheal aspiration cultures of six patients. Three out of six patients developed healthcare-associated pneumoniae due to B. cepacia. Environmental cultures in the ICUs revealed B. cepacia growth in 2% chlorhexidine-gluconate mouthwash solution that been used in the colonized patients as well as in samples obtained from the unused products. PFGE revealed the patient and a specific batch of chlorhexidine mouthwash solution samples had a 96% similarity. Conclusion: Contamination of medical solutions used in critical patient care could cause outbreaks and should be detected early by infection control teams.
  • Thumbnail Image
    PublicationOpen Access
    Diagnostic performance between RT-PCR and chest CT in outpatients with clinically suspected COVID-19
    (2023-08-01) TİGEN, ELİF; ERTÜRK ŞENGEL, BUKET; ÇİMŞİT, CANAN; APAYDIN KAYA, MEMNUNE ÇİĞDEM; KORTEN, VOLKAN; TİGEN E., ERTÜRK ŞENGEL B., ÇİMŞİT C., PERK GURUN H., APAYDIN KAYA M. Ç., KORTEN V.
    Objective: To investigate the diagnostic performance between chest computed tomography (CT) and reverse transcription-polymerase chain reaction (RT-PCR) in outpatients with suspected coronavirus disease 2019 (COVID-19). Patients and Methods: Between March and June 2020, a total of 812 patients with clinically suspected COVID-19 who underwent both chest CT and initial-single RT-PCR on admission to outpatient units were retrospectively enrolled. CT severity-score (CT-SS) was calculated and data were matched with PCR results. Results: Of 812 patients, 54% (439/812) had positive RT-PCR results, and 47% (425/812) had a positive chest CT scan. With RT-PCR results as reference, the sensitivity, specificity, accuracy of chest CT in defining COVID-19 infection were 60%, (95% CI 56-65%, 265/439 patients), 57% (95% CI 52-62%, 213/373), 59% (95% CI 55-62%, 478/812), respectively. Three hundred eighty-seven (47%) patients had no CT findings, 380/812 (46.8%) had mild, 45/812 (5.5%) had moderate, and no patients in the severe group Conclusion: Chest CT did not show high sensitivity for the diagnosis of COVID-19 for outpatients. We suggest RT-PCR should be the primary diagnostic tool. Chest CT might be considered if there is a strong clinical suspicion with repeatedly negative RT-PCR test results, ensuring infection prevention and control measures can be preserved.
  • Thumbnail Image
    PublicationOpen Access
    ISARIC-COVID-19 dataset: A Prospective, standardized, global dataset of patients hospitalized with COVID-19
    (2022-07-30) KORTEN, VOLKAN; Garcia-Gallo E., Merson L., Kennon K., Kelly S., Citarella B. W. , Fryer D. V. , Shrapnel S., Lee J., Duque S., Fuentes Y. V. , et al.
    © The Author(s) 2022.The International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC) COVID-19 dataset is one of the largest international databases of prospectively collected clinical data on people hospitalized with COVID-19. This dataset was compiled during the COVID-19 pandemic by a network of hospitals that collect data using the ISARIC-World Health Organization Clinical Characterization Protocol and data tools. The database includes data from more than 705,000 patients, collected in more than 60 countries and 1,500 centres worldwide. Patient data are available from acute hospital admissions with COVID-19 and outpatient follow-ups. The data include signs and symptoms, pre-existing comorbidities, vital signs, chronic and acute treatments, complications, dates of hospitalization and discharge, mortality, viral strains, vaccination status, and other data. Here, we present the dataset characteristics, explain its architecture and how to gain access, and provide tools to facilitate its use.
  • Thumbnail Image
    PublicationOpen Access
    Transmission of SARS-CoV-2 in Different Districts of a County in Istanbul, March to September 2020
    (SAGE PUBLICATIONS INC, 2021-07) TOPUZOĞLU, AHMET; Bilgin, Huseyin; Topuzoglu, Ahmet; Korten, Volkan
    Epidemics caused by airborne viruses in cities with large populations create a big problem as in the current COVID-19 pandemic. Cramped lifestyle, busy workplaces, crowded public transportation, and higher household member counts are responsible for the transmission of the disease. In Turkey, Istanbul has taken the lead in the number of cases since the beginning of the epidemic. The excess population density is the major cause for disease transmission. It is essential to monitor the contaminated regions with geographical information systems on city maps. Outbreak maps visualize and help analyze the patterns of transmission and serve as a communication and education tool. A dynamic heat map video of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) polymerase chain reaction positive cases in a county of Istanbul was generated. The heat map visualizes how the epidemic spread to all the districts and the cumulative cases increased in one county of Istanbul with real attack rates.
  • Thumbnail Image
    PublicationOpen Access
    Marmara Üniversitesi Pendik Eğitim ve ID_x000D_ Araştırma Hastanesi’nde 2014-2018 Yılları_x000D_ Arasındaki Kronik Hepatit C Prevalansı,_x000D_ Genotip Dağılımı ve Tedavi Yanıtları
    (2020) ERTÜRK ŞENGEL, BUKET; Betül ERTÜRK ŞENGEL;Tuğçe BAŞARI;Elif TÜKENMEZ TİGEN;Rabia CAN SARINOĞLU;Barış CAN;ULUHAN SİLİ;Volkan KORTEN
    Hepatit C dünyada yaygın olarak görülen ve mortaliteye neden olabilen ciddi bir hastalıktır.Bu çalışmada Marmara Üniversitesi Pendik Eğitim ve Araştırma Hastanesi’nebaşvuran hastalarda anti-HCV seropozitiflik sıklığının ve kronik viral hepatit C (HCV)tanısı konarak tedavi verilen hastaların genotip dağılımları ile tedavi başarılarınındeğerlendirilmesi amaçlanmıştır. Çalışmada retrospektif olarak Ocak 2014-Aralık 2018tarihleri arasında anti-HCV istemi yapılan serum örnekleri taranmıştır. Reaktif bulunanörneklerin HCV RNA pozitiflikleri ile genotip dağılımları ve kronik HCV tanısı ile tedaviverilen hastaların kalıcı viral yanıt başarı oranları değerlendirilmiştir. Total 76,413 hastadan100,100 serum örneğinde anti-HCV istemi yapılmış ve 1,808 (% 2,36) hastadapozitif bulunmuştur. Bu hastaların 1,286’sında (% 71) HCV RNA bakılmış ve 291 (% 23)hastada pozitif saptanmıştır. HCV RNA tespit edilen hastalarda 129’una (% 44) hastanemizdekronik HCV tanısı ile tedavi verilmiştir. En sık genotip 1b saptanmış olup, tedavisonrası 24’üncü haftada kalıcı viral yanıt hastaların % 87’sinde elde edilmiştir. Sonuçolarak antiviral tedavi ile virolojik başarı oranları yüz güldürücü olsa da halen tanı vetedavi alması gereken ancak tespit edilemeyen hasta sayısı da oldukça yüksektir.
  • Thumbnail Image
    PublicationOpen Access
    Trends and factors associated with modification or discontinuation of the initial antiretroviral regimen during the first year of treatment in the Turkish HIV-TR Cohort, 2011-2017
    (BMC, 2021-12) KORTEN, VOLKAN; Korten, Volkan; Gokengin, Deniz; Eren, Gulhan; Yildirmak, Taner; Gencer, Serap; Eraksoy, Haluk; Inan, Dilara; Kaptan, Figen; Dokuzoguz, Basak; Karaoglan, Ilkay; Willke, Ayse; Gonen, Mehmet; Ergonul, Onder
    Background: There is limited evidence on the modification or stopping of antiretroviral therapy (ART) regimens, including novel antiretroviral drugs. The aim of this study was to evaluate the discontinuation of first ART before and after the availability of better tolerated and less complex regimens by comparing the frequency, reasons and associations with patient characteristics. Methods: A total of 3019 ART-naive patients registered in the HIV-TR cohort who started ART between Jan 2011 and Feb 2017 were studied. Only the first modification within the first year of treatment for each patient was included in the analyses. Reasons were classified as listed in the coded form in the web-based database. Cumulative incidences were analysed using competing risk function and factors associated with discontinuation of the ART regimen were examined using Cox proportional hazards models and Fine-Gray competing risk regression models. Results: The initial ART regimen was discontinued in 351 out of 3019 eligible patients (11.6%) within the first year. The main reason for discontinuation was intolerance/toxicity (45.0%), followed by treatment simplification (9.7%), patient willingness (7.4%), poor compliance (7.1%), prevention of future toxicities (6.0%), virologic failure (5.4%), and provider preference (5.4%). Non-nucleoside reverse transcriptase inhibitor (NNRTI)-based (aHR = 4.4, [95% CI 3.0-6.4]; p < 0.0001) or protease inhibitor (PI)-based regimens (aHR = 4.3, [95% CI 3.1-6.0]; p < 0.0001) relative to integrase strand transfer inhibitor (InSTI)-based regimens were significantly associated with ART discontinuation. ART initiated at a later period (2015-Feb 2017) (aHR = 0.6, [95% CI 0.4-0.9]; p < 0.0001) was less likely to be discontinued. A lower rate of treatment discontinuation for intolerance/toxicity was observed with InSTI-based regimens (2.0%) than with NNRTI- (6.6%) and PI-based regimens (7.5%) (p < 0.001). The percentage of patients who achieved HIV RNA < 200 copies/mL within 12 months of ART initiation was 91% in the ART discontinued group vs. 94% in the continued group (p > 0.05). Conclusion: ART discontinuation due to intolerance/toxicity and virologic failure decreased over time. InSTI-based regimens were less likely to be discontinued than PI- and NNRTI-based ART.
  • Thumbnail Image
    PublicationOpen Access
    Frequency and associated factors for carbapenem-non-susceptible Bacteroides fragilis group bacteria colonization in hospitalized patients: Case control study in a university hospital in Turkey
    (ELSEVIER, 2021-10) ÖZAYDIN, AYŞE NİLÜFER; Toprak, Nurver Ulger; Akgul, Oncu; Bilgin, Huseyin; Ozaydin, Ayse Nilufer; Gelmez, Gulsen Altinkanat; Sayin, Elvan; Sili, Uluhan; Korten, Volkan; Soyletir, Guner
    Purpuse: The carbapenem-resistant Bacteroides fragilis group (CR-BFG) bacteria have been reported in several countries recently with increasing global attention. The high incidence of CR-BFG isolated from our hospitalized patients has become an important problem. Therefore, we aimed to determine the frequency and associated factors for intestinal colonization by carbapenem-non-susceptible BFG (CNS-BFG) among adult patients hospitalized at intensive care units, neurosurgery and internal medicine wards in our hospital. Methods: Rectal swabs (n = 1200), collected from 766 patients between February 2014 and March 2015, were inoculated onto kanamycin-vancomycin-leaked blood agar containing 0.125 mg/L meropenem. The isolates were identified by MALDI-TOF MS. Susceptibility testing was performed by agar dilution method. The carbapenemase gene (cfiA) was detected by PCR. Logistic regression analysis was used to evaluate the associated factors for intestinal colonization by CNS-BFG. Results: A total 180 non-duplicate BFG isolates were obtained from 164 patients. Ten different species, including Parabacteroides distasonis (n = 46, 25.6%), and Bacteroides fragilis (n = 30; 16.6%), were identified. Twenty- five percent of the isolates were non-susceptible to meropenem (MIC >2 mg/L). The highest prevalence of meropenem resistant strains (MIC >8 mg/L) was detected among B. fragilis (n = 12), followed by Parabacteroides spp. (n = 4). All but one B. fragilis strains were cfiA gene positive. Hospital admission, increasing Charlson score, use of antibiotics; including carbapenems in past three months, colonization with other accompanying carbapenem-resistant Gram negative bacteria (Enterobacteriaceae, Acinetobacter baumannii and Pseudomonas aeruginosa), and having undergone surgical operations were significantly associated with RCS- BFG colonization. Conclusions: The high carriage rate of CNS-BFG in hospitalized patients may lead to worse clinical outcomes, such as serious infections and mortality, and deserves attention.
  • Thumbnail Image
    PublicationOpen Access
    Comparison of SARS-COV-2 antibody assays in PCR negative and PCR positive Turkish patients
    (TUBITAK SCIENTIFIC & TECHNICAL RESEARCH COUNCIL TURKEY, 2021) KARAHASAN, AYŞEGÜL; Karahasan, Aysegul; Sarinoglu, Rabia Can; Can, Baris; BIlgIn, Huseyin; Cimsit, Nuri Cagatay; Korten, Volkan
  • Thumbnail Image
    PublicationOpen Access
    Clinical characteristics and risk factors associated with severe disease and outcome of patients with COVID-19
    (2022-03-01) KORTEN, VOLKAN; Ozel A. S., Altunal L. N., Aydin M., Unal B., Cam G., Ozer M. C., KORTEN V.
    Introduction: Since the beginning of the pandemic, factors associated with mortality in patients with corona virus infection disease 2019 (COVID-19) have been investigated. Comorbidities and increased age have been frequently reported to be associated with mortality. We aimed to evaluate the factors associated with unfavorable outcome of patients with COVID-19 at an early period of the pandemic. Methodology: This single center, retrospective, observational study was conducted among laboratory confirmed COVID-19 patients hospitalized between March 11 and May 5, 2020, at Umraniye Training and Research Hospital, Istanbul, Turkey. The effects of the severity of illness, comorbidities, symptoms, and laboratory findings on the clinical outcome were evaluated. Factors associated with unfavorable outcome (necessity of mechanical ventilation or death) were examined using Cox proportional hazards models. Results: Out of a total of 728 patients, 53.8% were men and median age 54 years. The 30-day mortality rate was 4.9% among all hospitalized patients. A logistic regression model identified six predictors of unfavorable clinical outcome: age, severity of illness, the numbers of comorbidities, lymphopenia, high levels of C-reactive protein, and procalcitonin. Conclusions: The mortality rate was lower among the patients with COVID-19, hospitalized during the early period of the pandemic. Older age, higher severity score on admission, the numbers of comorbidities, higher levels of C-reactive protein, procalcitonin, and lymphopenia were identified to be associated with unfavorable outcome of the hospitalized patients with COVID-19.