부산대학교 도서관

MICs of various β-lactam antibiotics by themselves and in combination with β-lactamase inhibitor (clavulanic acid) against extended spectrum β-lactamase (ESBL) producing strains of Escherichia coli and Klebsiellapneumoniae which were isolated from clinical materials were investigated. Furthermore, based on theresults obtained, a procedure to detect ESBL producing strains was proposed.The MICs of β-lactam antibiotics against β-lactamase producing strains were investigated. At first, β -lactamase was investigated by the drug sensitivity pattern (MIC) to, β-lactam antibiotics and by the substrateprofiles of β-lactamase extracted from the transconjugant of E. coli K-12 strains. After that, we classified theβ -lactamase producing gene by PCR method. Furthermore, a proposal was made for anantibiotic to be used in theconfirmation of mixed type β-lactamase. The data obtained by the above investigations were compiled and usedto determine the limit concentration of each β-lactam against β-lactamase producing strains including ESBL. Byusing β-lactam antibiotics at the following concentrations, it is considered possible to classify β-lactamase;ampicillin (64μg/ml), ampicillin/clavulanic acid (32/5μg/ml), piperacillin (64, μg/ml), cefotaxime (1μg/ml), cefpodoxime (2μg/ml), ceftazidime (1μg/ml), cefmetazole (4μg/ml), cefminox (2μg/ml), cefepime (0.5μg/ml), aztreonam (1μg/ml) and imipeneme (1μg/ml). This method may be used as a reference in investigating the prevalence of β-lactam resistant isolates by ESBL producing E. coli and K. pneumoniae.