Browsing by Author "Korten, Volkan"
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Item Clinical importance of extended-spectrum beta-lactamase (PER-1-type)-producing Acinetobacter spp. and Pseudomonas aeruginosa strains(Lippincott Williams & Wilkins, 2001-07) Vahaboğlu, Haluk; Coşkukan, Figen; Tansel, Özlem; Öztürk, Recep; Şahin, Nursu; Köksal, İftihar; Kocazeybek, Bekir; Tatman, Müşerref Otkun; Leblebicioğlu, Hakan; Özinel, Mehmet Ali; Korten, Volkan; Kocagöz, Sesin; Akalın, Emin Halis; Uludağ Üniversitesi/Tıp Fakültesi/Enfeksiyon Hastalıkları ve Klinik Mikrobiyoloji Anabilim Dalı.; AAU-8952-2020Recently, an extended-spectrum beta -lactamase (PER-I) was found to be disseminated among Acinetobacter spp, and Pseudomonas aeruginosa isolates in Turkey. A population-based cohort study was conducted to elucidate predictive mortality factors in patients with nosocomial infections caused by Acinetobacter spp. and P. aeruginosa, with particular reference to PER-1-type extended-spectrum beta -lactamase (ESBL) production. The study group comprised 16 and 21 non-survivors and 82 and 126 survivors in cohorts infected with Acinetobacter and E. aeruginosa, respectively. In the Acinetobacter-infected cohort, nosocomial pneumonia, hypotension and infection with a PER-positive isolate were independent predictors of mortality. In the P. aeruginosa-infected cohort, impaired consciousness, a PER-positive isolate, male sex and (with a negative relative risk) urinary tract infection were independent predictors of death. This study demonstrated the relationship of PER-1-type ESBL-producing Acinetobacter spp. and P. aeruginosa with poor clinical outcome.Item HIV-1 transmitted drug resistance mutations in newly diagnosed antiretroviral-naive patients in Turkey(Mary Ann Liebert, 2016-01-01) Sayan, Murat; Sargın, Fatma; İnan, Dilara; Sevgi, Dilek Y.; Çelikbaş, Aysel K.; Yaşar, Kadriye; Kaptan, Figen; Kutlu, Selda; Fışgın, Nuriye T.; İnci, Ayşe; Ceran, Nurgül; Karaoğlan, İlkay; Çağatay, Atahan; Çelen, Mustafa K.; Koruk, Suda T.; Ceylan, Bahadir; Yıldırmak, Taner; Korten, Volkan; Willke, Ayşe; Akalın, Halis; Uludağ Üniversitesi/Tıp Fakültesi/Enfeksiyon Hastalıkları Anabilim Dalı.; AAU-8952-2020; 57207553671HIV-1 replication is rapid and highly error-prone. Transmission of a drug-resistant HIV-1 strain is possible and occurs within the HIV-1-infected population. In this study, we aimed to determine the prevalence of transmitted drug resistance mutations (TDRMs) in 1,306 newly diagnosed untreated HIV-1-infected patients from 21 cities across six regions of Turkey between 2010 and 2015. TDRMs were identified according to the criteria provided by the World Health Organization's 2009 list of surveillance drug resistance mutations. The HIV-1 TDRM prevalence was 10.1% (133/1,306) in Turkey. Primary drug resistance mutations (K65R, M184V) and thymidine analogue-associated mutations (TAMs) were evaluated together as nucleos(t)ide reverse transcriptase inhibitor (NRTI) mutations. NRTI TDRMs were found in 8.1% (107/1,306) of patients. However, TAMs were divided into three categories and M41L, L210W, and T215Y mutations were found for TAM1 in 97 (7.4%) patients, D67N, K70R, K219E/Q/N/R, T215F, and T215C/D/S mutations were detected for TAM2 in 52 (3.9%) patients, and M41L + K219N and M41L + T215C/D/S mutations were detected for the TAM1 + TAM2 profile in 22 (1.7%) patients, respectively. Nonnucleoside reverse transcriptase inhibitor-associated TDRMs were detected in 3.3% (44/1,306) of patients (L100I, K101E/P, K103N/S, V179F, Y188H/L/M, Y181I/C, and G190A/E/S) and TDRMs to protease inhibitors were detected in 2.3% (30/1,306) of patients (M46L, I50V, I54V, Q58E, L76V, V82A/C/L/T, N83D, I84V, and L90M). In conclusion, long-term and large-scale monitoring of regional levels of HIV-1 TDRMs informs treatment guidelines and provides feedback on the success of HIV-1 prevention and treatment efforts.Item Karbapenemlerin gram-negatif patojenlere karşı in vitro aktivitelerinin karşılaştırmalı değerlendirmesi: COMPACT çalışması Türkiye verisi(Ankara Mikrobiyoloji Derneği, 2011-04) Korten, Volkan; Söyletir, Güner; Yalçın, Ata Nevzat; Oğünç, Dilara; Dokuzoğuz, Başak; Esener, Harika; Ulusoy, Sercan; Tünger, Alper; Aygen, Bilgehan; Sümerkan, Bülent; Arman, Dilek; Dizbay, Murat; Akova, Murat; Hasçelik, Gülşen; Eraksoy, Haluk; Başaran, Seniha; Köksal, İftihar; Bayramoğlu, Gülçin; Akalın, Halis; Sinirtaş, Melda; Uludağ Üniversitesi/Tıp Fakültesi/Enfeksiyon Hastalıkları ve Klinik Mikrobiyoloji Anabilim Dalı.; 57207553671; 6505818048Bu çalışmada, doripenem, imipenem ve meropenemin gram-negatif klinik izolatlara karşı in vitro aktivitesinin değerlendirilmesi amaçlanmıştır. Türkiye genelinde toplam 10 merkezden Eylül-Aralık 2008 tarihleri arasında, yoğun bakım ünitesi (YBÜ) ve YBÜ dışı hastalardan, toplam 596 adet klinik izolat toplanmıştır. Bunlardan %42.4’ü nozokomiyal pnömoni, %40.4’ü kan dolaşımı enfeksiyonu ve %17.1’i komplike intraabdominal enfeksiyon kaynaklı olup; %51.8’i YBÜ hastalarından alınmıştır. İzolatların %49.8’i Pseudomonas spp., %40.3’ü Enterobacteriaceae ve %9.9’u diğer gram-negatif etkenlerden oluşmaktadır. Her merkezde Etest® (AB Biodisk, Solna, İsveç) kullanılarak tüm izolatlar için doripenem, imipenem ve meropenemin minimum inhibitör konsantrasyonu (MİK) belirlenmiştir. İzolatlardan 188 (%31.5)’i en az bir karbapeneme dirençli bulunmuştur. Pseudomonas türlerine karşı doripenem için MİK50 değerleri meropeneme benzer olarak 1 mg/L bulunurken, imipenemden iki kat daha düşük olduğu izlenmiştir. Pseudomonas aeruginosa izolatlarının duyarlılıkları, doripenem için MİK 2 mg/L düzeyinde %64, imipenem ve meropenem için MİK 4 mg/L düzeyinde sırasıyla %53.9 ve %63 olarak tespit edilmiştir. Doripenem ve meropenem, Enterobacteriaceae türlerine karşı benzer aktivite gösterirken (MİK90 0.12 mg/L), imipenem dört kat daha az aktif (0.5 mg/L) bulunmuştur. Büyük çoğunluğunu Acinetobacter türlerinin oluşturduğu diğer gram-negatif basiller için doripenem MİK50 değeri 8 mg/L, diğer iki ilaç için ise 32 mg/L’dir. P.aeruginosa izolatları 8 mg/L MİK düzeyinde doripenem ile %84.2, meropenem ile %72.1 oranında inhibe olmuştur. Sonuç olarak doripenem, bu çalışmada toplanan patojenlere karşı genel olarak meropenem ile benzer ya da daha iyi; imipenemden ise belirgin olarak daha iyi in vitro aktiviteye sahiptir. Üç karbapenem arasında Pseudomonas türlerine karşı en aktif olan ilacın doripenem olduğu görülmüştür. Doripenem ve meropenem Enterobacteriaceae türlerine karşı benzer aktiviteye sahip olup, imipenemden en az dört kat daha aktiftir. Bu bulgular ışığında, hastanede YBÜ’de ya da YBÜ dışında tedavi gören nozokomiyal pnömoni, kan dolaşımı enfeksiyonu ve intraabdominal enfeksiyonu olan hastalar ile antibiyotik direnci gelişim riski olan hastaların antimikrobiyal tedavisinde doripenemin öne çıkan yeni bir antibiyotik olduğu kanısına varılmıştır.Item Outcomes of initial antiretroviral treatment (ART) among recently diagnosed HIV patients in HIV-TR cohort, 2011-2012(John Wiley & Sons Ltd, 2014-11) Korten, Volkan; Gökengin, Deniz; Fincancı, Muzaffer; Yıldırmak, Taner; Uzun Kes, Nuray; Fisgin, Nuriye Taşdelen; İnan, Dilara; Eraksoy, Haluk; Kaptan, Figen; Akalın, Halis; Uludağ Üniversitesi/Tıp Fakültesi/Enfeksiyon Hastalıkları Anabilim Dalı.; AAU-8952-2020Item Transmitted antiretroviral drug resistance mutations in newly diagnosed HIV-1 positive patients in Turkey(John Wiley & Sons Ltd, 2014-11) Sayan, Murat; Sargın, Fatma; Dilara, İnan; Sevgi, Dilek Yıldız; Kocagül Çelikba, Aysel; Kart Yaşar, Kadriye; Kaptan, Figen; Kutlu, Selda; Fışgın Taşdelen, Nuriye; İnci, Ayşe; Ceran, Nurgül; Karaoğlan, İlkay; Çağatay, Atahan; Celen, Mustafa K.; Koruk, Suda Tekin; Ceylan, Bahadır; Yıldırmak, Taner; Korten, Volkan; Willke, Ayşe; Akalın, Halis; Uludağ Üniversitesi/Tıp Fakültesi/Enfeksiyon Hastalıkları ve Klinik Mikrobiyoloji Anabilim Dalı.Item Vancomycin and daptomycin minimum inhibitory concentration distribution and occurrence of heteroresistance among methicillin-resistant Staphylococcus aureus blood isolates in Turkey(BMC, 2013-12-04) Sancak, Banu; Yağcı, Server; Gür, Deniz; Gülay, Zeynep; Öğünç, Dilara; Söyletir, Güner; Yalçın, Ata N.; Dündar, Devrim T.; Topçu, Ayşe W.; Akşit, Filiz; Usluer, Gaye; Hayran, Mutlu; Korten, Volkan; Özakın, Cüneyt; Akalın, Halis; Uludağ Üniversitesi/Tıp Fakültesi/Tıbbi Mikrobiyoloji Anabilim Dalı.; Uludağ Üniversitesi/Tıp Fakültesi/Enfeksiyon Hastalıkları ve Klinik Mikrobiyoloji Anabilim Dalı.; 0000-0001-5428-3630; AAG-8392-2021; AAU-8952-2020; 57200678942; 57207553671Background: The aim of this study was to determine the distribution of vancomycin and daptomycin MICs among methicillin-resistant Staphylococcus aureus (MRSA) blood isolates, the prevalence of heterogeneous vancomycin-intermediate S. aureus (hVISA) and the relationship between hVISA and vancomycin MIC values.Methods: A total of 175 MRSA blood isolates were collected from seven university hospitals in Turkey. All isolates were tested for susceptibility to vancomycin and daptomycin by reference broth microdilution (BMD) and by standard Etest method. BMD test was performed according to CLSI guidelines and Etest was performed according to the instructions of the manufacturer. All isolates were screened for the presence of the hVISA by using macro Etest (MET) and population analysis profile-area under the curve (PAP-AUC) methods.Results: The vancomycin MIC50, MIC90 and MIC ranges were 1, 2, and 0.5-2 μg/ml, respectively, by both of BMD and Etest. The daptomycin MIC50, MIC90 and MIC ranges were 0.5, 1 and 0.125 -1 μg/ml by BMD and 0.25, 0.5 and 0.06-1 μg/ml by Etest, respectively. The vancomycin MIC for 40.6% (71/175) of the MRSA isolates tested was >1 μg/ml by BMD. No vancomycin and daptomycin resistance was found among MRSA isolates. Percent agreement of Etest MICs with BMD MICs within ±1 doubling dilution was 100% and 73.1% for vancomycin and daptomycin, respectively. The prevalence of hVISA among MRSA blood isolates was 13.7% (24/175) by PAP-AUC method. MET identified only 14 of the hVISA strains (sensitivity, 58.3%), and there were 12 strains identified as hVISA that were not subsequently confirmed by PAP-AUC (specificity, 92.1%).Conclusions: Agreement between BMD and Etest MICs is high both for vancomycin and daptomycin. Daptomycin was found to be highly active against MRSA isolates including hVISA. A considerable number of isolates are determined as hVISA among blood isolates. As it is impractical to use the reference method (PAP-AUC) for large numbers of isolates, laboratory methods for rapid and accurate identification of hVISA need to be developed. © 2013 Sancak et al.; licensee BioMed Central Ltd.