Tıp Fakültesi / Faculty of Medicine

Permanent URI for this collectionhttps://hdl.handle.net/11727/1403

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search.filters.applied.f.rights: search.filters.rights.info:eu-repo/semantics/openAccessSubject: search.filters.subject.Klebsiella pneumoniae

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    In Vitro Efficacy of Ceftazidime-avibactam Against blaOXA-48-producing Klebsiella pneumoniae Isolates
    (2023) Cag, Yasemin; Kocoglu, Mucahide Esra; Caskurlu, Hulya; Haciseyitoglu, Demet; Mirza, Hasan Cenk; Guclu, Aylin Uskudar; Cetinkaya, Riza Aytac; Vahaboglu, Haluk; 0000-0002-8853-3893; F-1232-2015
    Introduction: The healthcare burden of carbapenem-resistant Klebsiella pneumoniae (K. pneumoniae) infections is growing. The newly developed beta-lactam/beta-lactamase inhibitor combination, ceftazidime-avibactam, shows promise in the treatment of such infections. We aimed to explore the in vitro efficacy of ceftazidime-avibactam against carbapenem-resistant K. pneumoniae isolates carrying the blaOXA-48 gene.Materials and Methods: The isolates were identified using MALDI-TOF MS (Brucker, USA). The isolates that were non-susceptible to imipenem, meropenem, or ertapenem by the disk diffusion method using the European Committee of Antimicrobial Susceptibility Testing (EUCAST) breakpoints were screenes. Minimum inhibitory concentration (MIC) values were determined via broth microdilution according to the EUCAST criteria. A time-kill study was performed according to Clinical and Laboratory Standards Institute guidelines. Beta-lactamase genes were screened for using polymerase chain reaction with previously published primers.Results: A total of 129 K. pneumoniae isolated between April 2011 and February 2021 were studied. Of these, 98, 23, and eight isolates carried the blaOXA-48, blaNDM, and blaOXA-48 with blaNDM genes, respectively. All isolates carrying the blaNDM gene were resistant to ceftazidime-avibactam. Approximately 79.6% of the blaOXA-48-positiveisolates were susceptible to ceftazidime-avibactam. The time-kill study for ceftazidime-avibactam was performed with one blaOXA-48-positive isolate (MIC, 4 mg/l). Ceftazidime-avibactam time-kill kinetics were evaluated in multiples of MIC. There was a decrease of >= 3-log10 in CFU/ml count at a concentration of 8, 16, and 32 MIC at 6 hours. The minimum bactericidal concentration was 8 mg/l.Conclusion: Ceftazidime-avibactam is an important treatment alternative alternative for blaOXA-48 positive carbapenem-resistant K. pneumoniae infections. The most rational approach to the treatment of carbapenem-resistant K. pneumoniae infections appears to be the initiatiion of targeted therapy according to culture antibiogram results or revision of the empirically initiated combination or monotherapy as early as possible according to culture antibiogram results.
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    Arising Prevalence of OXA-48 producer Escherichia coli and OXA-48 with NDM co-producer Klebsiella pneumoniae Strains
    (2019) Uskudar-Guclu, Aylin; Guney, Mustafa; Sig, Ali Korhan; Kilic, Selcuk; Baysallar, Mehmet; AAU-6196-2020
    Background/aim: This prospective study aimed to determine the presence of the most common carbapenemase genes, blaOXA-48, blaKPC, blaIMP, blaVIM and blaNDM on carbapenem resistant clinical K.pneumoniae and E.coli isolates. Materials and methods: Isolates were selected according to EUCAST guideline; gradient test and disc diffusion with both meropenem and ertapenem discs. Resistance rates of these isolates to other antimicrobial agents were also examined by disc diffusion method. Carbapenem resistance gene were investigated by using Real-Time PCR. Results: A total of 3845 E. coli and 1689 K. pneumoniae isolates from clinical samples between January 2015 and April 2017 were evaluated. The 419 isolates were found as carbapenem resistant but only the first resistant isolate (n=155; 126 K. pneumoniae and 29 E.coli) of each patient were included. Carbapenem resistant isolates were most frequently isolated from intensive care units (48.8%). Colistin was the most effective antibiotic (91.0%). The 121 (78.1%) of the tested isolates were positive for OXA-48 (103 K. pneumoniae and 18 E. coli) and 9 K. pneumoniae carrying blaNDM were also positive for blaOXA-48. VIM, IMP and KPC type carbapenemases were not detected in any isolates. Conclusion: Carbapenem-resistant pathogens have been shown to be able to develop resistance mechanisms with more than one carbapenemase encoding gene.