Production of a Cephalosporinase by Pseudomonas pyocyanea

Jago, Margaret; Migliacci, A.; Abraham, E. P.

doi:10.1038/199375a0

Cited by 27 publications

(10 citation statements)

References 7 publications

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“…As to $-lactamases used in this experiment, penicillinase is a constitutive enzyme while cephalosporinase is generally inducible. It was also reported that cephalosporinases produced by strans of Pseudomonas [12,18] and Enterobacter [10] are inducible enzymes.…”

Section: Discussionmentioning

confidence: 98%

Drug Resistance of Enteric Bacteria

Sawai

Mitsuhashi

Yamagishi

1968

Japanese Journal of Microbiology

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Section: Discussionmentioning

confidence: 98%

Drug Resistance of Enteric Bacteria

Sawai

Mitsuhashi

Yamagishi

1968

Japanese Journal of Microbiology

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“…This could also mean that the real inducer of ,B-lactamase biosynthesis is a cell wall precursor or a product formed as a by-product of cell wall biosynthesis after addition of penicillin. In this context it may be 6. Effect of various concentrations of benzylpenicillin on P. aeruginosa 1822s.…”

Section: Discussionmentioning

confidence: 99%

“…One of these enzyme types seems to be present in all strains of P. aeruginosa, namely, the inducible enzyme described by Sabath et al (6,20,21). Maximal induction is obtained using high concentrations of inducer for long periods (4,6,21).…”

mentioning

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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“…The formation of this enzyme is induced by the addition of P-lactam antibiotics. However, several authors have reported that high concentrations of inducer and long periods are required for maximal induction (8,14,34,35; review by Richmond and Sykes [32]). This makes the induction of fl-lactamase a rather unphysiological response, since growth is greatly impaired by these high concentrations of antibiotic inducer (32).…”

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confidence: 99%

Induction Kinetics of β-Lactamase Biosynthesis in Pseudomonas aeruginosa

Nordström

Sykes

1974

Antimicrob Agents Chemother

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The induction of β-lactamase in Pseudomonas aeruginosa 1822s was studied using benzylpenicillin as inducer. The specific rate of β-lactamase formation was constant throughout an induction experiment. Above a threshold (20 μg/ml), the specific activity increased linearly with the concentration of the inducer. Removal of the inducer resulted in a rapid cessation of β-lactamase biosynthesis. Inhibition of protein synthesis by starvation for a required amino acid or by the addition of chloramphenicol also led to an instantaneous arrest in enzyme formation. In the absence of inducer, a basal β-lactamase activity was formed. The basal and the induced enzymes seem to be identical since they had the same substrate profile, electrophoretic mobility, and molecular weight. In all these respects, induction of β-lactamase in Pseudomonas aeruginosa is analogous to induction of the lac operon in Escherichia coli . However, there was a long, concentration-dependent lag before β-lactamase was induced. This can be explained by the outer penetration barrier decreasing the rate of inducer uptake. The lag was significantly shorter for lysozyme-ethylenediaminetetraacetic acid-produced spheroplasts than for intact cells. Induction was obtained with all β-lactam antibiotics tested, but not with other agents affecting the cell envelope.

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Production of a Cephalosporinase by Pseudomonas pyocyanea

Cited by 27 publications

References 7 publications

Drug Resistance of Enteric Bacteria

Drug Resistance of Enteric Bacteria

Effects of Sublethal Concentrations of Benzylpenicillin on Pseudomonas aeruginosa

Induction Kinetics of β-Lactamase Biosynthesis in Pseudomonas aeruginosa

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