| Co-Investigator(Kenkyū-buntansha) |
FUKUCHI Kunihiko Showa University, School of Medicine, Associate Professor, 医学部, 助教授 (70181287)
CHEN Gelin Showa University, School of Medicine, Research assistant, 医学部, 助手 (60266111)
TAKAGI Yasushi Showa University, School of Medicine, Associate Professor, 医学部, 助教授 (30138490)
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| Research Abstract |
In this study, we surveyed the antibiotic resistant pattern of clinically isolated Gram-Negative Bacilli, such as Serratia marcescens, Klebsiella pneumoninae and E.coli and analysed the resistant genes from the highly resistant strains. In the first half of the study (1999 to 2000), we cloned and analysed the resistant gene of highly resistant S. marcescens isolated during 1996 to 1998.As a result, the metallo beta lactamase was appeared to be responsible for the resistance of S. marcescens, but TEM type ESBLs were not.
The second half ofthe study (2000-2001), we surveyed the cefotaxime and/or ceftazidime-resistant Gram-Negative Bacilli isolated during April 2000 to August 2000, and found four strains of resistant E.coli, one resistant K.pnewnoniae and one resistant Kiebsiik, oxiloca. The resistances of two out of four resistant E.coli strains, the K.pneumoninae and the K.oxitoca against cefotaxime were inhibited by Clavianic acid, indicating these strains were ESBLs producing. Further, the TEM genes were detected in these four ESBLs producing strains by PCR, and cloned the genes into pGEM1 vector. By comparing the sequence of the cloned TEM gene with TEM-1 sequence, no known ESBLs mutations were detected. Instead, from one E. coil strain, a novel mutation was detected in substrate binding region (nucleotide position 431-571). The mutation was G at nucleotide position 452 to A, accompanying amino acid substitution of valine to isoluecine. Further study is required to clarify whether this substitution is a case of ESBL mutation.
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