title: NDM-1 and rmtC-ProducingKlebsiella pneumoniaeIsolates in Turkey.
abstract: BACKGROUND
  The resistance of aminoglycosides in strains that produce beta-lactamase can be developed through the multidrug resistant encoding genes carried by common plasmids. Recently, the association between 16S rRNA methyltransferase resistance and beta-lactamase enzymes carried by the same plasmids has drawn increased attention from researchers, particularly the association in aminoglycoside-resistant strains with a minimum inhibitory concentration (MIC) of ≥ 256 µg/mL.
  
  
  OBJECTIVE
  We aimed to investigate the co-existence of 16S rRNA methyltransferase and beta-lactamase genes in multidrug resistant (MDR)Klebsiella pneumoniaestrains isolated from clinical samples.
  
  
  METHODS
  We determined the molecular mechanisms of aminoglycoside resistance and its relationship with resistance to carbapenem and beta-lactam group antibiotics in 40 extended-spectrum beta-lactamase (ESBL)-positive carbapenem- and aminoglycoside-resistantK. pneumoniaestrains. Multidrug resistantK. pneumoniaewas isolated from various clinical samples in the faculty of medicine of Cukurova University, Turkey. First, the resistance of aminoglycoside and beta-lactam antibiotics was phenotypically investigated using the Kirby-Bauer disk diffusion test, double disk synergy test, and modified Hodge test. The MIC values of aminoglycoside were determined using the agar dilution method. Polymerase chain reaction was performed to detect the carbapenemases, ESBL, and 16S rRNA methyltransferase genes. The results were confirmed by a sequence analysis.
  
  
  RESULTS
  TwentyK. pneumoniaestrains showed resistance to amikacin, and 40 were resistant to gentamicin. The MIC value was found to be > 512 µg/mL in five amikacin-resistant strains and > 128 µg/mL in 10 gentamicin-resistant isolates. ThermtCgene, a type of 16S rRNA methyltransferase, was amplified in four isolates (MIC amikacin: > 512 µg/mL, gentamicin: > 128 µg/mL). Of these four isolates, three had the blaNDM-1 gene and all contained at least one ESBL gene.
  
  
  CONCLUSIONS
  This study demonstrated the co-existence ofrmtCandblaNDM-1genes for the first time in Turkey. The spread of this resistant type should be monitored and limited through molecular surveillance.
authors.affiliation: Department of Microbiology, Ceyhan Veterinary Faculty, Cukurova University, Adana, Turkey.
authors.forename: Tulin
authors.initials: T
authors.lastname: Guven Gokmen
authors.affiliation: Department of Medical Microbiology, Faculty of Medicine, Cukurova University, Adana, Turkey.
authors.forename: Togrul
authors.initials: T
authors.lastname: Nagiyev
authors.affiliation: Department of Medical Microbiology, Faculty of Medicine, Cukurova University, Adana, Turkey.
authors.forename: Melda
authors.initials: M
authors.lastname: Meral
authors.affiliation: Department of Medical Microbiology, Faculty of Medicine, Cukurova University, Adana, Turkey.
authors.forename: Cansu
authors.initials: C
authors.lastname: Onlen
authors.affiliation: Department of Medical Microbiology, Faculty of Medicine, Cukurova University, Adana, Turkey.
authors.forename: Farzad
authors.initials: F
authors.lastname: Heydari
authors.affiliation: Department of Medical Microbiology, Faculty of Medicine, Cukurova University, Adana, Turkey.
authors.forename: Fatih
authors.initials: F
authors.lastname: Koksal
keywords: 16S rRNA -m7G methyltransferase; Beta-Lactamase NDM-1; Klebsiella pneumoniae; RmtC