| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 1998: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1997: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
An unexpected new enzymes, known as extended spectrum beta-lactamase(ESBLs) were prevalent in outside Japan. However, we do not appeared to have data about the accuracy of special tests for ESBLs for detecting the Japanese enzymes. The new enzymes(ESBLs) were tested among more than 700 isolates of E.coli, Kpneumoniae, Pmorganii, Cfreundii, and other gram-negative bacilli on the basis of resistance to piperacillin(PIPC). PIPC resistance was found in 14 % to 25% of these isolates, while cephem resistance was detected in 1.2% of PIPC resistant isolates of E.coliand Kpneumoniae. Over 98% of putative class A enzyme were susceptible to cephems, whease, amongst cephems positive isolates, 18 plasmids mediated by PIPC and cephem resistances were confirmed as ESBL producers. Putative ESBL producers were more resistant than non-producers to cefpodoxime, cefotaxime, ceftazidime, aztreonam, as well as cephaloridine, but remained ftdly susceptible to PIPC and culavulanic acis, cephamycins such as cefinetazole and fefoxitin, and carbapenems. These results were as expected, as the cephems and monobactam are substrates for the ESBLs whereas carbapenems are stable. DNA analysis of the ESBL genes from 18 plasmids by PGR method showed that fourteen belonged to TOHO-1 type, three to KIT-1 type and one to TEM type, respectively. These Japanese beta-lactamases have some similarities to ESBLS, but also have some differences, which suggest they should not be regarded as identical to the ESBLs derived from TEM and SHV
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