Evaluation of the Method to Screen Isolates of Extended-Spectrum -Lactamase-Producing Klebsiella pneumoniae and Escherichia coli Using Cefpodoxime Disk / 대한임상병리학회지

ABSTRACT

BACKGROUND: The prevalence of extended-spectrum -lactamase (ESBL)-producing Klebsiella pneumoniae and Escherichia coli has been increased in Korea, but the testing and reporting ESBL-mediated resistance remains unclear. We undertook a study to evaluate the method to screen isolates of ESBL-producing K. pneumoniae and E. coli using cefpodoxime disk. METHODS: Fifty-eight strains of K. pneumoniae and 28 strains of E. coli were tested for production of ESBLs by the double disk synergy test. Susceptibility to cefpodoxime, ceftazidime, cefotaxime, and aztreonam was determined by disk diffusion method. RESULTS: All strains that produced ESBLs were resistant to cefpodoxime, whereas those that not produced ESBLs were susceptible (97%) to this agents. The disk diffusion test exhibited 100% sensitivity and 97% specificity when NCCLS conventional interpretive criteria were used. All other oxyimino- -lactam agents tested were inferior discriminators between the two groups of organisms. When NCCLS ESBL interpretive criteria were used, the disk diffusion test using cefpodoxime exhibited 100% sensitivity and 83% specificity. CONCLUSIONS: Routine disk diffusion susceptibility test with cefpodoxime disk (10g) can be used to detect strains of ESBL-producing K. pneumoniae and E. coli without include supplemental testing for ESBL production.