+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

Use of fluorescent probes to determine MICs of amphotericin B and caspofungin against Candida spp. and Aspergillus spp

, : Use of fluorescent probes to determine MICs of amphotericin B and caspofungin against Candida spp. and Aspergillus spp. Journal of Clinical Microbiology 43(8): 3788-3792

We investigated the utility of mechanism-based fluorescent probes for determination of MICs (FMICs) of amphotericin B and caspofungin against Candida spp. and Aspergillus spp. Amphotericin B was selected as a membrane-active antifungal agent, and caspofungin was selected as a cell wall-active agent. FMICs were also compared to the MIC determined by CLSI (formerly NCCLS) methods. Five isolates per species of Candida albicans, Candida glabrata, Candida parapsilosis, Aspergillus fumigatus, and Aspergillus terreus were studied with either amphotericin B or caspofungin. The fluorescent probes, carboxyfluorescein diacetate (CFDA) for cytoplasmic esterase activity and dihexyloxacarbocyanine iodide (DiOC subscript 6) for cell membrane potential, were each added to their respective plates. MICs and FMICs were determined in at least three separate experiments (in duplicate). Fluorescence was measured using a 96-well plate fluorometer. For amphotericin B and caspofungin, the FMIC end point was the lowest concentration of drug at which the percent growth inhibition from treated organisms versus control organisms displayed 80% inhibition for amphotericin B and 50% inhibition for caspofungin as measured by a fluorescent signal. The MIC for amphotericin B was defined as the lowest concentration of antifungal displaying no visible growth for both Aspergillus and Candida spp. The MIC for caspofungin was the lowest concentration of drug that displayed a minimum effective concentration for Aspergillus spp. For Candida spp., the MIC for caspofungin was defined as the concentration at which the antifungal agent significantly inhibits the organism. The FMICs of both antifungals, as measured by the DiOC subscript 6 membrane probe, showed good agreement (83% to 100%), within one well dilution, with the MICs against amphotericin B and caspofungin for all species. Also, the FMICs measured by the CFDA cytoplasmic esterase probe reflecting damage due to cell wall or cell membrane showed strong agreement (79 to 100%) with the MICs of both amphotericin B and caspofungin for all species. There was no significant difference in comparisons of MIC and FMIC values (P [>/=] 0.05). The use of fluorescent probes provides a mechanism-based method of determination of MICs of amphotericin B and caspofungin against Candida spp. and Aspergillus spp. that correlates well with standard methods.


PMID: 16081911

DOI: 10.1128/JCM.43.8.3788-3792.2005

Other references

Siefert H.M.; Maruhn D.; Scholl H., 1986: Pharmacokinetics of ciprofloxacin 2nd communication distribution to elimination from tissues and organs following single or repeated administration of carbon 14 ciprofloxacin in albino rats. 1-Cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-[U-14C]piperazinyl)-3-quinoline carboxylic acid (ciprofloxacin, Bay o 9867; designated tradename: Ciprobay) was administered to male and to pregnant albino rats with single intravenous or oral doses of...

Ow, M.C.; Lau, N.C.; Hall, S.E., 2015: Small RNA library cloning procedure for deep sequencing of specific endogenous siRNA classes in Caenorhabditis elegans. In recent years, distinct classes of small RNAs ranging in size from ~21 to 26 nucleotides have been discovered and shown to play important roles in a wide array of cellular functions. Because of the abundance of these small RNAs, library preparat...

Kumar, A.S.n-Sarma, P., 1974: Studies on the genitalia of sixteen Indian species of tribeCyphicerinii (Coleoptera: Curculionidae: Eremninae) with special reference to their taxonomic importance. Journal 5 (2) 86-105

Schmidt, Karl P., 1932: Notes on New Guinean crocodiles. Crocodilus novae-guineae is redescr. on the basis of 2 juvenile specimens and 16 skulls from New Guinea. Skull characters of C. novae-guineae are compared with those of C. porosus from New Guinea and Borneo.

Breddam K.; Widmer F.; Johansen J.T., 1980: Influence of the substrate structure on carboxy peptidase y catalyzed peptide bond formation. For carboxypeptidase Y catalyzed peptide synthesis the coupling yields using peptide esters as substrates and amino acids as nucleophiles are strongly dependent on the C-terminal amino acid residue. A dependence on the length of the acyl donating...

Brown J.M.M.; Bronks R., 1991: Electromyographic basis of inaccurate movement its dependence upon the mode of muscle contraction. The electromyographic basis of inaccurate performance was investigated in two rapid precision grip skills controlled by concentric and eccentric muscle concentrations respctively. Surface electromyograms, recorded from the first dorsal interosseou...

Ostendorf, T.; Kunter, U.; van Roeyen, C.; Dooley, S.; Janjic, N.; Ruckman, J.; Eitner, F.; Floege, Jürgen., 2002: The effects of platelet-derived growth factor antagonism in experimental glomerulonephritis are independent of the transforming growth factor-beta system. Platelet-derived growth factor B-chain (PDGF-B)- and transforming growth factor beta (TGF-beta)-mediated accumulation of extracellular matrix proteins contributes to many progressive renal diseases. In vivo, specific antagonism of either PDGF-B or...

Anonymous, 1995: Vignettes: sportstech. Science 268(5212): 906-906

Barker, C.M.; Eldridge, B.F.; Reisen, W.K., 2010: Seasonal abundance of Culex tarsalis and Culex pipiens complex mosquitoes (Diptera: Culicidae) in California. Large-scale patterns in the seasonal abundance profiles of the arboviral mosquito vectors Culex tarsalis Coquillett and the species of the Culex pipiens complex were described based on a decade of counts from 868 New Jersey light traps located thr...

Mulazzi, D.; Baratta, P.; Calappi, E.; Parma, A.; Signoroni, G.; Tomaselli, P., 1994: Changes in thoracopulmonary compliance in normal and obese subjects in prone position. Agressologie: Revue Internationale de Physio-Biologie et de Pharmacologie Appliquees Aux Effets de L'agression 34 Spec No 1: 48-48