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    Comparative in vitro activity of plazomicin and older aminoglyosides against Enterobacterales isolates; prevalence of aminoglycoside modifying enzymes and 16S rRNA methyltransferases
    (Elsevier Science Inc, 2020) Gur, Deniz; Hasdemir, Ufuk; Cakar, Asli; Cavusoglu, Iffet; Celik, Tugce; Aksu, Burak; Zer, Yasemin
    Comparative in vitro activity of plazomicin and 4 older aminoglycosides was evaluated with broth microdilution in 714 blood isolates from 14 hospitals in Turkey. Isolates included Escherichia coli (n=320), Klebsiella spp. (n=294), Enterobacter spp. (n =69), Serratia marcescens (n=20). and Citrobacter spp. (n=11). Isolates resistant to older aminoglycosides (n=240) were screened for aminoglycoside modifying enzyme genes: aac(6')-Ib, aac(3)-Ia, aac(3)-IIa, ant(2 '')-Ia. Isolates with high MICs for plazomicin (n=41) were screened for 165 rRNA methyltransferase genes (armA, rmtA, rmtB, rmtC, rmtD, rmtE, rmtF, rmtG, rmtH, npmA) and 2 carbapenemase genes (blaOXA-48, blaNDM-1). Overall, resistance to plazomicin, amikacin, netilmicin, gentamicin, and tobramycin was 7.7%, 7.4%, 31.5%, 32.9%, and 34.7%, respectively. aac(6')-Ib and aac(3)-IIa were the most common AME genes. Co-occurrence of blaNDM-1 with armA and rmtC and blaOXA-48 with armA was striking. Enterobacter cloacae carrying rmtC+blaNDM-1, S. marcescens with armA+blaOXA-48, and rmtF+ blaOXA-48 in K. pneumoniae were reported for the first time. (C) 2020 Elsevier Inc. All rights reserved.
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    In vitro susceptibility of respiratory isolates of streptococcus pneumoniae and streptococcus pyogenes to telithromycin and 11 other antimicrobial agents: Turkish results of E-Baskett-II Surveillance Study
    (Ankara Microbiology Soc, 2007) Gur, Deniz; Mulazimoglu, Lutfiye; Unal, Serhat
    In respiratory tract infections, therapy is often empirical and there is a need for local data on the rate of resistance to available antimicrobials. In this multicentre study which is a part of the international e-BASKETT-II surveillance study, respiratory isolates of Streptococcus pneumoniae (n=260) and Streptococcus pyogenes (n=312) collected between September 2002 and June 2003 from 18 hospitals in Turkey were tested against penicillin G, amoxicillin, cefuroxime, ceftriaxone, erythromycin, clarithromycin, azithromycin, clindamycin, telithromycin, tetracycline, levofloxacin and vancomycin. Antibiotic susceptibilities were determined with disk diffusion method and confirmed with broth dilution method following the CLSI guidelines. Isolates which were resistant to erythromycin were genotyped by polymerase chain reaction. In S.pneumoniae 11.5% of the isolates were highly and 22.7% were intermediately resistant to penicillin. Rate of resistance to erythromycin, clarithromycin, azithromycin was 17.3%, and 21.5% of the isolates were resistant to tetracycline. Resistance to levofloxacin and vancomycin was not observed and only one isolate was found intermediately resistant (MIC=2 mu g/mL) to telithromycin. Genotypes in erythromycin-resistant isolates were ermB (77.8%), mefA (17.8%) and ermB+mefA (2.2%). S.pyogenes isolates were uniformly susceptible to beta-lactams and vancomycin, and only one isolate was intermediately resistant to levofloxacin. Macrolide resistance was observed in 1.3% of the isolates and three out of these harboured the mefA gene. One isolate with an MIC of 4 mu g/mL for telithromycin had ermB gene. Telithromycin has demonstrated a good in vitro activity against macrolide-resistant respiratory tract isolates. As a result, e-BASKETT-II surveillance study has been one of the most extensive in vitro studies comparing telithromycin to available antimicrobial agents for respiratory tract infections in Turkey.
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    Investigation of Carbapenemases in Carbapenem-Resistant Escherichia coli and Klebsiella pneumoniae Strains Isolated in 2014 in Turkey
    (Ankara Microbiology Soc, 2016) Cakar, Asli; Akyon, Yakut; Gur, Deniz; Karatuna, Onur; Ogunc, Dilara; Baysan, Betil Ozhak; Coplu, Nilay; Cagatay, Mustafa; Kilic, Abdullah; Baysallar, Mehmet; Bakici, Zahir; Celik, Cem; Gulay, Zeynep; Aydemir, Sohret; Tunger, Alper; Kilic, Huseyin; Ercal, Baris Derya; Toraman, Zulal Asci; Zer, Yasemin; Buyuktas, Ayse; Ay, Selma; Aktas, Zerrin; Kayacan, Cigdem; Bayramoglu, Gulcin; Aydin, Faruk; Dundar, Devrim; Hasdemir, Ufuk; Ayas, Ramazan; Yanik, Keramettin; Gunaydin, Murat; Guducuoglu, Huseyin; Parlak, Mehmet
    Carbapenems are the choice of treatment in infections caused by multidrug resistant Enterobacteriaceae. In recent years carbapenem-resistant Enterobacteriaceae isolates due to carbapenemases have been increasingly reported worldwide. Multicenter studies on carbapenemases are scarce in Turkey. The aim of this study was to determine the distribution of carbapenemases from different parts of Turkey as a part of the European Survey of Carbapenemase Producing Enterobacteriaceae (EuSCAPE) project. Beginning in November 2013, carbapenem-resistant isolates resistant to at least one of the agents, namely imipenem, meropenem, and ertapenem were sent to the coordinating center. Minimum inhibitory concentrations for these carbapenems were determined by microdilution tests following EUCAST guidelines. Production of carbapenemase was confirmed by combination disk synergy tests. Types of carbapenemases were investigated using specific primers for VIM, IMP; NDM, KPC and OXA-48 genes by multiplex polymerase chain reaction. In a six month period, 155 suspected carbapenemase-positive isolates were sent to the coordinating center of which 21 (13.5%) were E.coli and 134 (86.5%) were K.pneumoniae. Nineteen (90.5%) strains among E.coli and 124 (92.5%) strains among K.pneumoniae were shown to harbour at least one carbapenemase gene by molecular tests, with a total of 92.3% (143/155). Carbapenemases were determined as a single enzyme in 136 strains (OXA-48: 84.6%; NDM: 6.3%; VIM: 2.8%; IMP: 1.4%) and as a combination in seven isolates (OXA-48 + NDM: 2.1%; OXA-48 + VIM: 2.1%; VIM + NDM: 0.7%). KPC was not detected in any of the isolates. According to the microdilution test results, resistance to imipenem, meropenem and ertapenem in OXA-48 isolates were 59.5%, 52.9% and 100%, respectively. The combination disk synergy test was 100% compatible with the molecular test results. As most of the OXA-48 producing isolates were susceptible to meropenem but all were resistant to ertapenem, ertapenem seems to be the most sensitive agent in screening carbapenemases in areas where OXA-48 is prevalent and phenotypic combination tests can be useful in centers where molecular tests are not available.