Postantibiotic effect of amikacin and rifapentine against Mycobacterium avium complex.

TitlePostantibiotic effect of amikacin and rifapentine against Mycobacterium avium complex.
Publication TypeJournal Article
Year of Publication1992
AuthorsBermudez LE, Wu M, Young LS, Inderlied CB
JournalThe Journal of infectious diseases
Volume166
Issue4
Pagination923-6
Date Published1992 Oct
ISSN0022-1899
KeywordsAmikacin, Dose-Response Relationship, Drug, Leprostatic Agents, Microbial Sensitivity Tests, Mycobacterium avium Complex, Rifampin, Time Factors
Abstract

Postantibiotic effect (PAE) has received little attention in the therapy of chronic intracellular infections, such as those caused by mycobacteria. Amikacin is active therapeutically against Mycobacterium avium complex, even though serum levels exceed the MIC for only a few hours. To determine the PAE of amikacin and rifapentine for M. avium, bacteria were exposed to concentrations of 1x, 4x, and 10x the MIC of each drug for up to 120 min. Regrowth of M. avium was compared with similarly diluted untreated cultures. No PAE was observed on an inoculum of 10(4) bacteria when rifapentine was used at 5x MIC, although a slight inhibition of growth was obtained at 10x MIC for 2 h. For amikacin, PAE was observed up to 48 h at concentrations of 4x and 8x MIC and exposure times of 30-120 min. A PAE of 22 h was seen with 10(7) cfu of M. avium during incubation for 30 min with amikacin at 4x MIC. These results show that amikacin, unlike rifapentine, has a long PAE against M. avium.

Alternate JournalJ. Infect. Dis.