Open AccessTRC‐1: Emergence of a clavulanic acid‐resistant TEM β‐lactamase in a clinical strain
Author(s) -
Thomson C.J.,
Amyes S.G.B.
Publication year - 1992
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1992.tb05194.x
Subject(s) - clavulanic acid , enzyme , plasmid , microbiology and biotechnology , isoelectric focusing , escherichia coli , isoelectric point , bacteria , biology , strain (injury) , gene , chemistry , biochemistry , antibiotics , amoxicillin , genetics , anatomy
A novel TEM‐derived plasmid‐encoded β‐lactamase, resistant to inhibition by clavulanic acid, has been identified in a clinical strain of Escherichia coli found in Scotland. The β‐lactamase gene was carried on an 81‐kb plasmid that conferred no other resistances. The novel enzyme conferred resistance to the amoxycillin/clavulanic acid combination on the host bacterium. The β‐lactamase has a p I of 5.25 and lies between the PSE‐4 and SAR‐1 β‐lactamases on an isoelectric focusing gel. This β‐lactamase has a M r value of 25 000, similar to the TEM‐1 enzyme and a comparable substrate profile. Its most significant difference is that it is inhibited by clavulanic acid 100‐fold less efficiently than the TEM‐1 enzyme. The enzyme was confirmed to be derived from the TEM enzymes by probing the plasmid DNA with an intragenic gene probe for TEM‐1. This is the first report of a clinical bacterium carrying a TEM‐enzyme that confers resistance to clavulanic acid combinations and we have designated the β‐lactamase as TRC‐1.