Browsing by Author "Gonen, Mehmet"

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Characteristics And Outcomes Of Carbapenemase Harbouring Carbapenem-Resistant Klebsiella Spp. Bloodstream Infections: A Multicentre Prospective Cohort Study In An OXA-48 Endemic Setting
(2022) Isler, Burcu; Ozer, Berna; Cinar, Gule; Aslan, Abdullah Tarik; Vatansever, Cansel; Falconer, Caitlin; Dolapci, Istar; Simsek, Funda; Tulek, Necla; Demirkaya, Hamiyet; Menekse, Sirin; Akalin, Halis; Balkan, Ilker Inanc; Aydin, Mehtap; Tigen, Elif Tukenmez; Demir, Safiye Koculu; Kapmaz, Mahir; Keske, Siran; Dogan, Ozlem; Arabaci, Cigdem; Yagci, Serap; Hazirolan, Gulsen; Bakir, Veli Oguzalp; Gonen, Mehmet; Chatfield, Mark D.; Forde, Brian; Saltoglu, Nese; Azap, Alpay; Azap, Ozlem; Akova, Murat; Paterson, David L.; Can, Fusun; Ergonul, Onder; 35301623
A prospective, multicentre observational cohort study of carbapenem-resistant Klebsiella spp. (CRK) bloodstream infections was conducted in Turkey from June 2018 to June 2019. One hundred eighty-seven patients were recruited. Single OXA-48-like carbapenemases predominated (75%), followed by OXA-48-like/NDM coproducers (16%). OXA-232 constituted 31% of all OXA-48-like carbapenemases and was mainly carried on ST2096. Thirty-day mortality was 44% overall and 51% for ST2096. In the multivariate cox regression analysis, SOFA score and immunosuppression were significant predictors of 30-day mortality and ST2096 had a non-significant effect. All OXA-48-like producers remained susceptible to ceftazidime-avibactam.
Comparison Of Ceftazidime-Avibactam Susceptibility Testing Methods Against OXA-48-Like Carrying Klebsiella Blood Stream Isolates
(2022) Isler, Burcu; Vatansever, Cansel; Ozer, Berna; Cinar, Gule; Aslan, Abdullah Tarik; Stewart, Adam; Simos, Peter; Falconer, Caitlin; Bauer, Michelle J.; Forde, Brian; Harris, Patrick; Simsek, Funda; Tulek, Necla; Demirkaya, Hamiyet; Menekse, Sirin; Akalinj, Halis; Balkan, Ilker Inanc; Aydin, Mehtap; Tigen, Elif Tukenmez; Demir, Safiye Koculu; Kapmaz, Mahir; Keske, Siran; Dogan, Ozlem; Arabaci, Cigdem; Yagci, Serap; Hazirolan, Gulsen; Bakir, Veli Oguzalp; Gonen, Mehmet; Saltoglu, Nese; Azap, Alpay; Azap, Ozlem; Akova, Murat; Ergonul, Onder; Paterson, David L.; Can, Fusun; 35843111
Ceftazidime-avibactam exhibits good in vitro activity against carbapenem resistant Klebsiella carrying OXA-48-like enzymes. We tested two hundred unique carbapenem resistant Klebsiella blood stream isolates (71% with single OXA-48-like carbapenemases, including OXA-48, n = 62; OXA-232, n = 57; OXA-244, n = 17; OXA-181, n = 5) that were collected as part of a multicentre study against ceftazidime-avibactam using Etest (bioMerieux, Marcyl'Etoile, France), 10/4 mg disc (Thermo Fisher) and Sensititre Gram Negative EURGNCOL Plates (Lyophilized panels, Sensititre, Thermo Fisher) with the aim of comparing the performances of the Etest and disc to that of Sensititre. Ceftazidime-avibactam MIC50/90 was 2/> 16 mg/L for the entire collection and was 2/4 mg/L for single OXA-48-like producers. Categorical and essential agreements between the Etest and Sensititre were 100% and 97%, respectively. Categorical agreement between the disc and Sensititre was 100%. Etest and 10/4 mg discs are suitable alternatives to Sensititre for ceftazidime-avibactam sensitivity testing for OXA-48-like producers. (C) 2022 Elsevier Inc. All rights reserved.
Promoters of Colistin Resistance in Acinetobacter Baumannii Infections
(2019) Nurtop, Elif; Bilman, Fulya Bayindir; Menekse, Sirin; Azap, Ozlem Kurt; Gonen, Mehmet; Ergonul, Onder; Can, Fusun; https://orcid.org/0000-0002-3171-8926; 30964377; AAK-4089-2021
Objectives: We aimed to describe the mechanisms of colistin resistance in Acinetobacter baumannii. Materials and Methods: Twenty-nine patients diagnosed with colistin-resistant A. baumannii infection were included to the study. The mutations in pmrCAB, lpxA, lpxC, and lpxD genes, expression of pmrCAB, carbapenemases, and mcr-1 positivity were studied. Results: Twenty-seven (93%) of the patients received IV colistin therapy during their stay, and the case fatality rate was 45%. All mutations in pmrC and pmrB were found to be accompanied with a mutation in lpxD. The most common mutations were I42V and L150F in pmrC (65%), E117K in lpxD (65%), and A138T in pmrB (58.6%). The colistin minimum inhibitory concentrations (MICs) of the isolates having any of these four mutations were higher than the isolates with no mutations (p < 0.001). The two most common mutations in pmrC (I42V and L150F) were found to be associated with higher expressions of pmrA and pmrC and higher colistin MIC values (p = 0.010 and 0.031). All isolates were bla(OXA-23) positive. Conclusion: Coexistence of the lpxD mutation along with mutations in pmrCAB indicates synergistic function of these genes in development of colistin resistance in A. baumannii.