An Increase in the Clinical Isolation of Acquired AmpC beta-Lactamase-Producing Klebsiella pneumoniae in Korea from 2007 to 2010.
10.3343/alm.2013.33.5.353
- Author:
Min Jeong PARK
1
;
Taek Kyung KIM
;
Wonkeun SONG
;
Jae Seok KIM
;
Han Sung KIM
;
Jacob LEE
Author Information
1. Department of Laboratory Medicine, Hallym University College of Medicine, Chuncheon, Korea. swonkeun@hallym.or.kr
- Publication Type:Brief Communication
- Keywords:
Klebsiella pneumoniae;
AmpC beta-lactamases;
DHA-1;
CMY-2
- MeSH:
Anti-Bacterial Agents/pharmacology;
Bacterial Proteins/*genetics;
DNA, Bacterial/genetics;
Enterobacteriaceae Infections/*epidemiology/*microbiology;
Escherichia coli/drug effects/enzymology/isolation & purification;
Hospitals, University/statistics & numerical data;
Humans;
Klebsiella pneumoniae/drug effects/enzymology/isolation & purification/*physiology;
Microbial Sensitivity Tests;
Multiplex Polymerase Chain Reaction;
Proteus mirabilis/drug effects/enzymology/isolation & purification;
Republic of Korea/epidemiology;
beta-Lactamases/*genetics
- From:Annals of Laboratory Medicine
2013;33(5):353-355
- CountryRepublic of Korea
- Language:English
-
Abstract:
We investigated the occurrence and genetic basis of AmpC beta-lactamase (AmpC)-mediated antibiotic resistance, by examining Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis isolates at a university hospital, from 2007 to 2010. The ampC genes were detected by multiplex AmpC PCR, and AmpC-positive strains were subjected to DNA sequencing. Extended-spectrum beta-lactamase (ESBL) production was assessed using the ESBL disk test based on the utilization of boronic acid. Carbapenem-resistant isolates were further investigated by the modified Hodge test, a carbapenemase inhibition test and SDS-PAGE experiments. AmpC expression was detected in 1.6% of E. coli (39 DHA-1, 45 CMY-2, and 1 CMY-1) isolates, 7.2% of K. pneumoniae (39 DHA-1, 45 CMY-2, and 1 CMY-1) isolates, and 2.5% of P. mirabilis (8 CMY-2 and 1 CMY-1) isolates. Of the 198 acquired AmpC producers, 58 isolates (29.3%) also produced an ESBL enzyme. Among the acquired AmpC-producing K. pneumoniae isolates, the minimum inhibitory concentration (MIC) MIC50/MIC90 values for cefoxitin, cefotaxime, cefepime, imipenem, and meropenem were >32/>32, 16/>32, 1/16, 0.25/0.5, and <0.125/0.125 microg/mL, respectively. The MIC values for carbapenem were > or =2 microg/mL for 2 K. pneumoniae isolates, both of which carried the blaDHA-1 gene with a loss of OmpK36 expression, but were negative for carbapenemase production. The acquisition of AmpC-mediated resistance in K. pneumoniae isolates increased, as did the proportion of AmpC and ESBL co-producers among the hospital isolates. The accurate identification of isolates producing AmpCs and ESBLs may aid in infection control and will assist physicians in selecting an appropriate antibiotic regimen.
