Penicillinase-type of beta-lactamase responsible for the ampicillin resistance in Escherichia coli NTUH 9501-1.
beta-Lactamases which hydrolyze the amide bonds of beta-lactam rings of penicillins and cephalosporins are widely distributed among microorganisms and play an important role in microbial resistance to beta-lactam antibiotics. These enzymes have been classified into penicillinase-type and cephalosporinase-type on the basis of their substrate specificity. Several clinical isolates of Escherichia coli from National Taiwan University Hospital (NTUH) were shown to be ampicillin-resistant and found to contain the penicillinase-type of beta-lactamase. Escherichia coli NTUH 9501-1 was chosen for further genetic analysis by recombinant DNA technology. DNAs from NTUH 9501-1 were isolated and digested with Pst I. The cellular DNA fragments were then joined with the vector DNA fragments derived from pHC 79 cosmid by Pst I digestion and followed by calf intestine alkaline phosphatase treatment. The recombinant cosmid DNAs were transfected and propagated in the wild type of E. coli DH 5. The transduced cells were selected on the basis of growth on LB plates containing ampicillin. The recombinant cosmid DNAs were re-isolated from the transductant cells and digested with Pst I. The cellular DNA fragments isolated by gel electrophoresis were able to transform DH 5 (amp(s)) to amp(r) cells. The results suggested that transposon-like DNA sequences coding for the ampicillinase-type of beta-lactamases were responsible for the penicillin resistance in E. coli NTUH 9501-1.
Lin
J K
JK
Huang
T S
TS
Luh
K T
KT
D000668:Ampicillin Resistance / Q000235:genetics; D055598:Chemical Phenomena; D002621:Chemistry; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D005798:Genes, Bacterial; D010405:Penicillinase / Q000235:genetics / Q000502:physiology*
D010405:Penicillinase