Comparison of the Substrate Specificities of the β-Lactamases from Klebsiella aerogenes 1082E and Enterobacter cloacae P99

Abstract

A potent fl-lactamase (EC 3.5.2.6) produced by a strain of Klebsiella aerogenes (K. pneumoniae), 1082E, isolated from a hospital patient, has been examined. Its properties were different from those of most gram-negative f-lactamases previously reported. The enzyme has been partly purified, and its activity against a range of substrates has been compared with that of the enzyme from Enterobacter cloacae (Aerobacter cloacae) P99. The K. aerogenes enzyme, although predominantly a penicillinase, had a wide range of specificity. In addition to hydrolyzing the cephalosporins, it attacked the normally fl-lactamaseresistant compounds methicillin and cloxacillin as well as cephalosporin analogues with the same acyl substituents. The results obtained with the E. cloacae enzyme confirmed its cephalosporinase activity and showed that, unlike the enzyme from K. aerogenes, it was relatively inactive against the penicillins. The fl-lactamases produced by gram-negative bacteria differ considerably in their substrate specificities. Although most of the enzymes hydrolyze penicillin G, cephalothin, and cephaloridine, comparatively few hydrolyze methicillin or cloxacillin.

Structural and kinetic studies on β-lactamase K1 from Klebsiella aerogenes

“…We now show that limited structural studies strongly suggest that the fl-lactamase produced by Klebsiella aerogenes 1082E (Ross & Boulton, 1973) belongs to structural class A. Earlier work on this enzyme (Hamilton-Miller, 1963;Marshall et al, 1972;Ross & Boulton, 1973;Richmond, 1980;Bush et al., 1982) did not utilize the highly purified enzyme, which is now readily obtained by affinity chromatography (Cartwright & Waley, 1984). Hence the pH-dependence of the steady-state kinetic parameters have now been measured.…”

“…Klebsiella aerogenes (K1082E) was grown in a fermenter (15-litre scale) as described by Marshall et al (1972). After 4 h at 30°C, the cells were harvested by centrifugation and resuspended in 300 ml of 30 mmsodium phosphate/10 mM-citric acid buffer, pH 6.3.…”

The effects of βbT‐lactams on the isoelectric focusing of βbT‐lactamases

“…PSE-1 and PSE-2 were produced by Pseudomonas aeruginosa PU2 1 (Matthew TEM-4, TEM-7, TEM-9, TEM-El, TEM-E2, TEM-E3, and Sykes 1977 ;Matthew 1978, respectively). Klebsiella pneumoniae 1082E produced the K-1 klebsiella chromosomal b-lactamase (Marshall et al 1972).…”

Cell Envelopes of Gram negative Bacteria: Composition, Response to Chelating Agents and Susceptibility of Whole Cells to Antibacterial Agents

“…The sensitivity of the 7 strains to 3 j3-lactam antibiotics and to other antibacterial agents is described in Table 4. Of the strains tested, the following possess a constitutive j3-lactamase : R+ TEM ('cephalosporinase' and 'penicillinase' activity : Richmond & Sykes, 1973), P99 (predominantly a 'cephalosporinase' : Jack & Richmond, 1970) and K1 (predominantly a 'cephalosporinase' : Marshall, Ross, Chanter & Harris, 1972). Inducibility of j3-lactamase in the two P. aeruginosa strains was not investigated.…”