Format

Send to

Choose Destination
J Antimicrob Chemother. 1989 Apr;23(4):485-91.

The post-antibiotic effect defined by bacterial morphology.

Author information

1
Department of Epidemiology and Infection Control, Bronx Lebanon Hospital Center, New York.

Abstract

Three strains of Escherichia coli were incubated with either ciprofloxacin or ampicillin. Filamentation of bacteria was observed after 1-2 h. After 5 h of contact with either drug the percentage of filaments exceeded 90%. The organisms were washed and incubated on drug free medium. Antibiotics when bound to an enzyme render that enzyme inactive; upon removal of the organisms from the antibiotic, the synthesis of enzymes resumes. The period of time encompassing the inactive enzymatic state of the organism at the time of removal from the drug to the time that enzymes restore complete function is our definition of the post-antibiotic effect (pae). Bacterial morphology reflects the variations in activity of these enzymes. The pae was determined by both the morphology of the organisms and the current growth kinetic method. The presence of 10% filaments and 90% bacilli was selected to indicate the endpoint of the pae by morphological criteria. The pae by morphology was 4 h for ciprofloxacin and 3 h for ampicillin. By the growth kinetics method it was 2 h for ciprofloxacin and zero for ampicillin.

PMID:
2663811
DOI:
10.1093/jac/23.4.485
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Silverchair Information Systems
Loading ...
Support Center