Effect of beta-lactamase location in Escherichia coli on penicillin synergy.

Applied Microbiology
H C Neu

Abstract

Resistance to ampicillin in Escherichia coli is due generally to the presence of a beta-lactamase (penicillinase). Resistant strains have been found to fall into two groups: those with high-level resistance (1,000 mug/ml or greater) and those with low-level resistance (8 to 250 mug/ml). Most of the high-level resistant organisms posses beta-lactamases whose synthesis is episomally mediated. These strains release penicillinase from the cell when they are subjected to osmotic shock. Low-level resistant strains do not release the enzyme with osmotic shock. High-level resistant strains are not susceptible to the synergistic action of a penicillinase-resistant penicillin with ampicillin. Seventy eight per cent of low-level resistant strains are susceptible to the synergistic action of ampicillin and oxacillin. The two types of beta-lactamases are similar in regard to most properties; both enzymes are subject to competitive inhibition by penicillinase-resistant penicillins. The difference in location in the cell might explain why only some strains of E. coli are susceptible to the synergistic action of penicillin combinations.

References

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Citations

Feb 1, 1974·Antimicrobial Agents and Chemotherapy·A Roupas, J S Pitton
Jan 1, 1974·Antimicrobial Agents and Chemotherapy·H R OnishiE O Stapley
Mar 1, 1980·Antimicrobial Agents and Chemotherapy·R YogevA T Davis
Oct 22, 2016·Annals of the New York Academy of Sciences·Boahemaa Adu-OppongGautam Dantas
Jun 1, 1976·Antimicrobial Agents and Chemotherapy·T C EickhoffR D Baines
Nov 1, 2020·European Journal of Medicinal Chemistry·Carlie WetzelChun Wu
Jan 11, 2020·Frontiers in Microbiology·Alejandro Del Barrio-DuqueStéphane Compant

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