Journal of Pure and Applied MicrobiologyVol. 7 No. 4

Aminoglycoside Resistance in Clinical Klebsiella pneumoniae Isolates

Xiaolong Tang1,2, Shuyu Cai1,2*, Jia Chen4, Lifa XU1, Jian Wang1, Wenyue Li1, Xiuyun Zhang1, Lin Sun1, Liyi Fang1, Xin Zhou1, Zhenyou Jiang3*, Peng Liu1 and Liuhua Wei5

1Stem cell Engineering Research Center, School of Medical, Anhui University of Science & Technology, Huainan - 232 001, China. 2Department of Laboratory Medicine, Tianjin Medical College, Tianjin - 300 222, China; 3Department of Traditional Chinese Medicine, School of Medical, Jinan University, Guangzhou - 510 632, China. 4Department of Microbiology and Immunology, School of Medical, Jinan University, Guangzhou - 510 632, China. 5Clinical Laboratory, Liuzhou workers Hospital, Guangxi - 545 005, China

Received on 23 September 2013 and accepted on 06 November 2013

 

ABSTRACT

To analyze the Klebsiella pneumoniae (K. pneumoniae) susceptibility to aminoglycosides antibiotics in clinical isolates in Guangzhou, and to characterize the molecular resistance mechanisms of K. pneumoniae against aminoglycosides (AGs) agents. We examined 1495 strains clinical isolates of Klebsiella pneumoniae from Microbiology Laboratory of the Guangdong Provincial Traditional Chinese Medicine in China between 2008 and 2012 by MicroScan Wa1kAway-96. And detected Minimal inhibitory concentrations (MICs) of amikacin, gentamicin and tobramycin to K. pneumoniae by agar dilution methods. Isolates were analyzed by polymerase chain reaction (PCR) amplification techniques to determine whether six aminoglycoside modifying enzymes (AMEs) genes ( aac(3)-a!, aac(6')-Ib, ant(3")-I, ant(2")-I, aac(3)-I, aac(6')-a!)and six 16S rRNA mehtylases genes (armA, rmtA, rmtB, rmtC, rmtD, npmA) were present. Additionally, 16S rRNA methylase gene positive isolates were chosen for a plasmid transfer test to explore whether the resistance marker was located on the transfer plasmid. Pulsed-field gel electrophoresis was used for genotyping 16S rRNA methylase gene positive isolates. A total of 265 isolates was identified as resistant to one or more aminoglycosides, with resistance rates to amikacin, tobramycin and gentamicin of 4.15%(62/1495), 9.50%(142/1495), and 16.05%(240/1495), respectively. Among the 265 resistant aminoglycoside isolates, 84.5% carried resistance genes (180 isolates carried AMEs and 44 isolates carried both AMEs and methylase genes). Aminoglycoside resistance in Guangzhou clinical isolates of K. pneumoniae is still low, and kept stable over the last 5 years; frequency of AMEs and 16S rRNA methylase in K. pneumoniae was low.

Keywords : Klebsiella pneumoniae; aminoglycosides; aminoglycoside modifying enzymes (AMES); 16S rRNA methylase; antimicrobial resistance; gene.