Abstract
The effects of selected antibiotics on Escherichia coli were studied by flow cytometry with the fluorescent anionic membrane potential probe bis-(1,3-dibutylbarbituric acid) trimethine oxonol [DiBAC4(3)]. The actions of azithromycin, cefuroxime, and ciprofloxacin at five times the MIC on E. coli were compared by the traditional CFU assay and flow cytometry. Changes in viable counts of bacteria determined with DiBAC4(3) and by flow cytometry following treatment with the antibiotics showed trends similar to those found by the CFU assays. However, viable counts determined by flow cytometry following antibiotic treatment were 1 to 2 logs higher than those determined by the corresponding CFU assays. All the results obtained by flow cytometry were provided within 10 min after sampling, whereas the conventional CFU assay results took at least 18 h. The results indicated that flow cytometry is a sensitive analytical technique that can rapidly monitor the physiological changes of individual microorganisms following antibiotic action and can provide information on the mode of action of a drug. The membrane potential probe DiBAC4(3) provides a robust flow cytometric indicator for bacterial cell viability.
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- Bashford C. L., Alder G. M., Gray M. A., Micklem K. J., Taylor C. C., Turek P. J., Pasternak C. A. Oxonol dyes as monitors of membrane potential: the effect of viruses and toxins on the plasma membrane potential of animal cells in monolayer culture and in suspension. J Cell Physiol. 1985 Jun;123(3):326–336. doi: 10.1002/jcp.1041230306. [DOI] [PubMed] [Google Scholar]
- Boye E., Løbner-Olesen A. Bacterial growth control studied by flow cytometry. Res Microbiol. 1991 Feb-Apr;142(2-3):131–135. doi: 10.1016/0923-2508(91)90020-b. [DOI] [PubMed] [Google Scholar]
- Bräuner T., Hülser D. F., Strasser R. J. Comparative measurements of membrane potentials with microelectrodes and voltage-sensitive dyes. Biochim Biophys Acta. 1984 Apr 11;771(2):208–216. doi: 10.1016/0005-2736(84)90535-2. [DOI] [PubMed] [Google Scholar]
- Gant V. A., Warnes G., Phillips I., Savidge G. F. The application of flow cytometry to the study of bacterial responses to antibiotics. J Med Microbiol. 1993 Aug;39(2):147–154. doi: 10.1099/00222615-39-2-147. [DOI] [PubMed] [Google Scholar]
- Jepras R. I., Carter J., Pearson S. C., Paul F. E., Wilkinson M. J. Development of a robust flow cytometric assay for determining numbers of viable bacteria. Appl Environ Microbiol. 1995 Jul;61(7):2696–2701. doi: 10.1128/aem.61.7.2696-2701.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Loew L. M. Design and characterization of electrochromic membrane probes. J Biochem Biophys Methods. 1982 Aug;6(3):243–260. doi: 10.1016/0165-022x(82)90047-1. [DOI] [PubMed] [Google Scholar]
- Mason D. J., Power E. G., Talsania H., Phillips I., Gant V. A. Antibacterial action of ciprofloxacin. Antimicrob Agents Chemother. 1995 Dec;39(12):2752–2758. doi: 10.1128/aac.39.12.2752. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Shapiro H. M. Cell membrane potential analysis. Methods Cell Biol. 1990;33:25–35. doi: 10.1016/s0091-679x(08)60509-9. [DOI] [PubMed] [Google Scholar]
- Steen H. B., Boye E. Bacterial growth studied by flow cytometry. Cytometry. 1980 Jul;1(1):32–36. doi: 10.1002/cyto.990010108. [DOI] [PubMed] [Google Scholar]
- Steen H. B., Boye E., Skarstad K., Bloom B., Godal T., Mustafa S. Applications of flow cytometry on bacteria: cell cycle kinetics, drug effects, and quantitation of antibody binding. Cytometry. 1982 Jan;2(4):249–257. doi: 10.1002/cyto.990020409. [DOI] [PubMed] [Google Scholar]
- Wilson H. A., Chused T. M. Lymphocyte membrane potential and Ca2+-sensitive potassium channels described by oxonol dye fluorescence measurements. J Cell Physiol. 1985 Oct;125(1):72–81. doi: 10.1002/jcp.1041250110. [DOI] [PubMed] [Google Scholar]