Characteristics and dynamics of bacterial populations during postantibiotic effect determined by flow cytometry.
Average rating
Cast your vote
You can rate an item by clicking the amount of stars they wish to award to this item.
When enough users have cast their vote on this item, the average rating will also be shown.
Star rating
Your vote was cast
Thank you for your feedback
Thank you for your feedback
Issue Date
1998-05-01
Metadata
Show full item recordCitation
Antimicrob. Agents Chemother. 1998, 42(5):1005-11Abstract
Changes in bacterial ultrastructure after antibiotic exposure and during the postantibiotic effect (PAE) have been demonstrated by electron microscopy (EM). However, EM is qualitative and subject to individual interpretation. In contrast, flow cytometry gives qualitative and quantitative information. The sizes and nucleic acid contents of Escherichia coli and Pseudomonas aeruginosa were studied during antimicrobial exposure as well as during the PAE period by staining the organisms with propidium iodide and analyzing them with flow cytometry and fluorescence microscopy. The effects of ampicillin, ceftriaxone, ciprofloxacin, gentamicin, and rifampin were studied for E. coli, whereas for P. aeruginosa imipenem and ciprofloxacin were investigated. After exposure of E. coli to ampicillin, ceftriaxone, and ciprofloxacin, filamentous organisms were observed by fluorescence microscopy. These changes in morphology were reflected by increased forward light scatter (FSC) and nucleic acid content as measured by flow cytometry. For the beta-lactams the extent of filamentation increased in a dose-dependent manner after drug removal, resulting in formation of distinct subpopulations of bacteria. These changes peaked at 20 to 35 min, and bacteria returned to normal after 90 min after drug removal. In contrast, the subpopulations induced by ciprofloxacin did not return to normal until > 180 min after the end of the classically defined PAE. Rifampin resulted in formation of small organisms with low FSC, whereas no distinctive characteristics were noted after gentamicin exposure. For P. aeruginosa an identifiable subpopulation of large globoid cells and increased nucleic acid content was detected after exposure to imipenem. These changes persisted past the PAE, as defined by viability counting. Swollen organisms with increased FSC were detected after ciprofloxacin exposure, even persisting during bacterial growth. In summary, for beta-lactam antibiotics and ciprofloxacin, the PAE is characterized by dynamic formation of enlarged cell populations of increased nucleic acid content, whereas rifampin induces a decrease in size and nucleic acid content in the organisms. Flow cytometry is an ideal method for future studies of bacterial phenotypic characteristics during the PAE.Description
To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldAdditional Links
http://aac.asm.org/cgi/content/abstract/42/5/1005Collections
Related articles
- Flow cytometric investigation of filamentation, membrane patency, and membrane potential in Escherichia coli following ciprofloxacin exposure.
- Authors: Wickens HJ, Pinney RJ, Mason DJ, Gant VA
- Issue date: 2000 Mar
- Different patterns of bacterial DNA synthesis during postantibiotic effect.
- Authors: Gottfredsson M, Erlendsdóttir H, Gudmundsson A, Gudmundsson S
- Issue date: 1995 Jun
- The postantibiotic effect induced by antimicrobial combinations.
- Authors: Gudmundsson S, Erlendsdóttir H, Gottfredsson M, Gudmundsson A
- Issue date: 1990
- Postantibiotic effect of a combination of antimicrobial agents on pseudomonas aeruginosa.
- Authors: Sood P, Mandal A, Mishra B
- Issue date: 2000 May-Jun
- Ultrastructural alterations of bacteria during the postantibiotic effect.
- Authors: Gottfredsson M, Erlendsdóttir H, Kolka R, Gudmundsson A, Gudmundsson S
- Issue date: 1993 May-Jun