Korean J Clin Microbiol.  2007 Oct;10(2):119-122.

Isolation Frequency of Extended Spectrum beta-Lactamase Producing Escherichia coli, Klebsiella species, and Proteus mirabilis

• Uh Y
• Hwang GY
• Kwon O
• Yoon KJ
• Kim HY

Abstract

BACKGROUND: Accurate detection of extended spectrum beta-lactamase (ESBL) is important because ESBLproducing organisms may appear susceptible to oxyimino- beta-lactams in standard susceptibility tests, but are considered to be clinically resistant to these drugs. And continued monitoring of isolation trend of ESBL-producing organisms is essential for the guideline settlement of antibiotic usage and infection control program.
METHODS
Disk diffusion test using the Clinical and Laboratory Standards Institute's ESBL phenotypic confirmatory test were performed on 5,511 clinical isolates of Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, and Proteus mirabilis during the recent six years (April 2001-March 2007). The ESBL producer was defined as an organism showing an increase in the zone diameter of > or =5 mm for either cefotaxime or ceftazidime with clavulanic acid versus that without clavulanic acid (CTC confirmatory test, CZC confirmatory test, respectively).
RESULTS
The ESBL-positive rates were 34.8% in K. pneumoniae, 9.3% in K. oxytoca, 8.4% in E. coli, and 6.5% in P. mirabilis. Among the ESBL-positive organisms, the detection rates of ESBL CTC and CZC confirmatory tests were as follows: 91.3% vs 68.7% in K. pneumoniae, 96.3% vs 44.4% in K. oxytoca, 94.8% vs 45.4% in E. coli, and 100% vs 20% in P. mirabilis. ESBL-producing K. pneumoniae had shown a continuously increasing trend from 24.3% in 2001 to 46.4% in 2006.
CONCLUSION
Both of the ESBL confirmatory tests should be simultaneously tested for the accurate detection of ESBL-producing K. pneumoniae, K. oxytoca, E. coli, and P. mirabilis. In addition, an active infection control approach is needed for ESBL-producing K. pneumoniae.

Keyword

Extended-spectrum beta-lactamase; Klebsiella pneumoniae; Escherichia coli; Klebsiella oxytoca; Proteus mirabilis

MeSH Terms

beta-Lactamases*
beta-Lactams
Cefotaxime
Ceftazidime
Clavulanic Acid
Diffusion
Escherichia coli*
Escherichia*
Infection Control
Klebsiella oxytoca
Klebsiella pneumoniae
Klebsiella*
Mirabilis
Pneumonia
Proteus mirabilis*
Proteus*
Cefotaxime
Ceftazidime
Clavulanic Acid
beta-Lactamases
beta-Lactams