title: High rate of aminoglycoside resistance in CTX-M-15 producing Klebsiella pneumoniae isolates in Tehran, Iran.
abstract: OBJECTIVE
  To determine the prevalence of extended-spectrum beta lactamases (ESBLs), the bla(CTX-M) genes, and aminoglycoside modifying enzymes genes in clinical isolates of Klebsiella pneumoniae (K. pneumoniae).
  
  
  METHODS
  We collected 200 nonduplicate clinical isolates of K. pneumoniae in hospitals in Tehran, Iran. We determined antibacterial susceptibility and confirmed ESBL production via the disk diffusion and minimum inhibitory concentration (MIC) methods. We identified bla(CTX-M) and aminoglycoside modifying enzymes genes via polymerase chain reaction (PCR).
  
  
  RESULTS
  We detected 72 (36.0%) ESBL-positive K. pneumoniae, in which the bla(CTX-M-15) was dominant (62.5%). A total of 54.0% of isolates were resistant to at least 1 tested aminoglycoside; also, we detected aac(6')-Ib in 42.5% of isolates and aac(3)-IIa in 35.1% of them. We observed a high rate of aminoglycoside-resistant genes (71.0%) among bla(CTX-M-15)-carrying isolates.
  
  
  CONCLUSIONS
  We report that CTX-M-15 is the dominant type of CTX-M, which associates with entities that have high aminoglycoside resistance. Continuous surveillance and monitoring of this entity are needed because the codissemination of multiple drug-resistant genes with K. pneumoniae may become a serious therapeutic problem.
authors: Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran; najarp_s@modares.ac.ir.
authors: Shahin Najar
authors: SN
authors: Peerayeh
authors: Gastroenterology and Liver Diseases Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran;
authors: Elham
authors: E
authors: Rostami
authors: Department of Hepatitis and AIDS, Pasteur Institute of Iran, Tehran, Iran;
authors: Seyed Davar
authors: SD
authors: Siadat
authors: Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
authors: Safura
authors: S
authors: Derakhshan
mesh_terms: D000617:Aminoglycosides / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial / Q000235:genetics; D006801:Humans; D007492:Iran; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000201:enzymology; D008826:Microbial Sensitivity Tests; D001618:beta-Lactamases / Q000096:biosynthesis*
chemical_list: D000617:Aminoglycosides; C473109:beta-lactamase CTX-M-15; D001618:beta-Lactamases
keywords: CTX-M1; CTX-M15; ESBLs; Klebsiella pneumoniae; aac (6′)-Ib; aac(3)-IIa