Klebsiella pneumoniae 2207, from Durban, was resistant to cefoxitin and β-lactamase inhibitor combinations as well as oxyimino-aminothiazolyl cephalosporins. β-Lactamases with isoelectric points of 5.4, 5.6, 7.6, 8.2 and 8.4 were found. DNA hybridisation identified two BamHI and three HindIII fragments carrying blaTEM, and two SalI fragments carrying bla SHV. At least two genes encoded TEM-1 enzyme; one blaSHV copy encoded SHV-5 but the other determined SHV-23, a novel SHV-5 variant with conservative amino-acid substitutions far from the catalytic site. The pI 8.4 activity was an AmpC-type enzyme. Determinants of the pI 5.6 and 7.6 activities were not identified.
- AmpC β-lactamase
- Extended-spectrum β-lactamases
- K. pneumoniae