Induction Kinetics of β-Lactamase Biosynthesis in
            <i>Pseudomonas aeruginosa</i>

Nordström, Kurt; Sykes, R. B.

doi:10.1128/aac.6.6.734

Cited by 30 publications

(23 citation statements)

References 37 publications

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“…Induced P-lactamase formation in Gram-negative bacteria is considered to be controlled negatively by a repressor (Nordstrom & Sykes, 1974;Sawai et al, 1977;Gootz & Sanders, 1983); the enzyme can be induced by various penicillins, cephalosporins (Minami et a]., 1980) and a carbapenem antibiotic (Grappel et al, 1984). The present work has demonstrated that monocyclic P-lactam antibiotics are also inducers of p-lactamase.…”

Section: Discussionmentioning

confidence: 74%

“…Many P-lactamases, which are responsible for resistance to P-lactam antibiotics in pathogenic bacteria, are inducible enzymes (Richmond & Sykes, 1973), and the mechanisms of induction have been studied by many investigators (Nordstrom & Sykes, 1974;Sawai et al, 1977;Gootz & Sanders, 1983). However, studies on the kinetics of induced P-lactamase formation in Gramnegative bacteria have been more difficult than those on P-galactosidase formation in Escherichiu coli (Pardee & Prestidge, 1961 ;Kepes, 1963;Boezi & Cowie, 1961).…”

Section: Introductionmentioning

confidence: 99%

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Induction of -Lactamase in Proteus vulgaris

Okonogi¹,

Kuno²,

Higashide³

1986

Microbiology

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Various P-lactam antibiotics, including monocyclic P-lactams, induced the P-lactamase of Proteus vulgaris; when clinical isolates were induced by benzylpenicillin, each strain produced a single 0-lactamase but the activity per milligram dry weight differed from strain to strain. The Plactamases of the P. vulgaris strains were heterogeneous with respect to their isoelectric points, but had almost the same specific activities, substrate specificities and Michaelis constants. The kinetics of P-lactamase formation were investigated in three strains, each with a different /Ilactamase activity. Differential rates of enzyme synthesis and peak activity depended on the concentration of inducer. The plots of the reciprocals of the differential rates versus the reciprocals of the inducer concentrations were linear, and the maximum rate of enzyme synthesis and the concentration of the inducer giving half-maximum induction were determined from this double reciprocal plot. The maximum rates of enzyme synthesis were different in the three strains. The kinetic analysis of /I-lactamase formation revealed that the P-lactamase activities in a single bacterial species were determined by differences in the rate of enzyme synthesis and not by differences in the properties of the enzyme.

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Section: Discussionmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Induction of -Lactamase in Proteus vulgaris

Okonogi¹,

Kuno²,

Higashide³

1986

Microbiology

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“…This makes the induction of 0-lactamase a rather unphysiological response, since growth is greatly impaired by these high concentrations of antibiotic inducer. A study of the kinetics of,-lactamase induction is reported in the companion paper (14).…”

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confidence: 99%

Effects of Sublethal Concentrations of Benzylpenicillin on Pseudomonas aeruginosa

Nordström

Sykes

1974

Antimicrob Agents Chemother

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Pseudomonas aeruginosa produces a low basal level of β-lactamase (0.002 to 0.004 IU/mg of protein when benzylpenicillin is used as substrate). The β-lactamase specific activity can be increased several hundredfold by growing the bacteria in the presence of β-lactam antibiotics. This induction was studied in Pseudomonas aeruginosa 1822s. The single-cell resistance to benzylpenicillin was 750 μg/ml. In liquid culture all concentrations of benzylpenicillin tested (25 to 2,000 μg/ml) affected the bacteria similarly: β-lactamase formation was induced, the cells became cholate sensitive, growth rate decreased, filaments were formed, and β-lactamase was excreted. The effect appeared earlier the higher the concentration of the antibiotic. Most of the effects obtained are concerned with the functioning of the outer membrane. The excretion of β-lactamase seems to be due to an opening of the periplasmic volume rather than to lysis of the cells. Carbenicillin gave the same effects as benzylpenicillin at the same concentrations; the 10-fold lower resistance to carbenicillin than to benzylpenicillin can be explained by the inability of the inducible β-lactamase to hydrolyze carbenicillin. The induced β-lactamase was first cell bound and to a great extent located in the periplasmic volume, but later it was excreted into the medium. This extracellular activity was responsible for the detoxification of the medium. This is analogous to the behavior of gram-positive bacteria rather than to that of Enterobacteriaceae .

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“…Whereas typical P . aeruginosa strains synthesise only basal levels of enzyme in the absence of inducers (Nordstrom and Sykes, 1974), the resistant isolates synthesise substantially larger amounts. It has been demonstrated that cefotaxime, cefoperazone and azlocillin are hydrolysed significantly by SA enzyme and ceftazidime is slightly labile (Livermore, 1983a and b;Jacobs, Livermore and Davy, in press).…”

Section: Discussionmentioning

confidence: 99%