Pol J Microbiol. 2018. Article in Press. DOI: 10.21307/pjm-2018-034

ATOSSA GHASEMNEJAD1, MONIR DOUDI2* and NOUR AMIRMOZAFARI3

1 Department of Biology, Science and Research branch, Islamic Azad University, Tehran, Iran
2 Department of Microbiology, Falavarjan branch, Islamic Azad University, Esfahan, Iran
3 Department of Microbiology, Iran University of Medical Sciences, Tehran, Iran

*Corresponding author: M. Doudi, Department of Microbiology, Falavarjan branch, Islamic Azad University, Esfahan, Iran; e-mail: monir.doodii@gmail.com

Submitted 11 October 2017, revised 20 December 2017, accepted 24 March 2018

Abstract
Klebsiella pneumoniae carbapenemase (KPC) have become a major therapeutic challenge because of its increasingly fast dissemination throughout the world. Accurate detection of KPC is essential for optimal treatment. The Clinical and Laboratory Standards Institutes (CLSI) for fast detection of KPC producers currently recommend Modified Hodge Test (MHT) and Carba NP test. MHT can directly detect carbapenemase production in Enterobacteriaceae isolates. The current study was conducted to evaluate the capacity of MHT with two carbapenem disks for accurate detection of KPC. MHT was performed according to guidelines of CLSI to identify isolates with carbapenem resistance. In doing so, two substrates of MHT were assigned into two groups for examination: meropenem and ertapenem groups. A total of 96 non-repetitive clinical isolates of Klebsiella pneumoniae were tested. The presence of the blaKPC gene in each MHT-positive isolate was examined by PCR. A total of 54 isolates exhibited reduced susceptibility or resistance to carbapenems. Sensitivity of MHT with two carbapenem disks was similar. Specificity of the MHT with meropenem disk was 64% and with ertapenem disk was 53%. Detection of KPC by MHT with meropenem disk was found to be more effective than with ertapenem disk. Based on our results, the presence of KPC does not in itself influence the categorization of resistance. Therefore, the use of MHT with ertapenem disk for the rapid detection of KPC among K. pneumoniae for infection control should not be recommended.

Key words: Klebsiella pneumoniae, carbapenem disks, detection method, Modified Hodge Test, KPC

© 2018 Atossa Ghasemnejad et al.
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License (https://creativecommons.org/licenses/by-nc-nd/4.0/).