8
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Susceptibility testing of Candida albicans isolated from oropharyngeal mucosa of HIV + patients to fluconazole, amphotericin B and Caspofungin. killing kinetics of caspofungin and amphotericin B against fluconazole resistant and susceptible isolates

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          A clear understanding of the pharmacodynamic properties of antifungal agents is important for the adequate treatment of fungal infections like candidiasis. For certain antifungal agents, the determination of Minimal Fungicidal Concentration (MFC) and time kill curve could be clinically more relevant than the determination of the Minimal Inhibitory Concentration (MIC). In this study, MIC and MFC to fluconazole, amphotericin B and caspofungin against C. albicans isolates and the killing patterns obtained with caspofungin and amphotericin B against susceptible and resistant strains to fluconazole were determined. The results of MICs showed that all C. albicans isolates were highly susceptible to amphotericin B, but two isolates were fluconazole resistant. The comparative analysis between MIC and MFC showed that MFC of fluconazole was fourfold higher than MIC in 41.9% of the C. albicans isolates. Same values of MFC and MIC of amphotericin B and caspofungin were found for 71% of the isolates. Correlation between time kill curves and MFC of amphotericin B and caspofungin against all 4 isolates tested was observed. The caspofungin killing effect was more evident at MFC in 6 hours of incubation than at MIC in this time, suggesting dependence of concentration. The similarity of results of time-kill curve and MFC values indicate that determination of MFC is an alternative for the detection of the fungicidal activity of these drugs.

          Related collections

          Most cited references31

          • Record: found
          • Abstract: found
          • Article: not found

          Comparison of In vitro activities of the new triazole SCH56592 and the echinocandins MK-0991 (L-743,872) and LY303366 against opportunistic filamentous and dimorphic fungi and yeasts.

          The in vitro antifungal activities of SCH56592, MK-0991, and LY303366 against 83 isolates of Acremonium strictum, Aspergillus flavus, Aspergillus fumigatus, Aspergillus terreus, Bipolaris spp., Blastomyces dermatitidis, Cladophialophora bantiana, Fusarium oxysporum, Fusarium solani, Histoplasma capsulatum, Phialophora spp., Pseudallescheria boydii, Rhizopus arrhizus, Scedosporium prolificans, and Sporothrix schenckii were compared. The in vitro activities of these agents against 104 isolates of yeast pathogens of Candida spp., Cryptococcus neoformans, and Trichosporon beigelii were also compared. MICs were determined by following a procedure under evaluation by the National Committee for Clinical Laboratory Standards (NCCLS) for broth microdilution testing of the filamentous fungi (visual MICs) and the NCCLS M27-A broth microdilution method for yeasts (both visual and turbidimetric MICs). The in vitro fungicidal activity of SCH56592 was superior (minimum fungicidal concentrations [MFCs], 0.25 to 4 microgram/ml for 7 of 18 species tested) to those of MK-0991 and LY303366 (MFCs, 8 to >16 microgram/ml for all species tested) for the molds tested, but the echinocandins had a broader spectrum of fungicidal activity (MFCs at which 90% of strains are inhibited [MFC90s], 0.5 to 4 microgram/ml for 6 of 9 species tested) than SCH56592 (MFC90s, 0.25 to 8 microgram/ml for 4 of 9 species tested) against most of the yeasts tested. Neither echinocandin had in vitro activity (MICs, >16 microgram/ml) against C. neoformans and T. beigelii, while the SCH56592 MICs ranged from 0.12 to 1.0 microgram/ml for these two species. The MICs of the three agents for the other species ranged from <0.03 to 4 microgram/ml. These results suggest that these new agents have broad-spectrum activities in vitro; their effectiveness in the treatment of human mycoses is to be determined.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Influence of test conditions on antifungal time-kill curve results: proposal for standardized methods.

            This study was designed to examine the effects of antifungal carryover, agitation, and starting inoculum on the results of time-kill tests conducted with various Candida species. Two isolates each of Candida albicans, Candida tropicalis, and Candida glabrata were utilized. Test antifungal agents included fluconazole, amphotericin B, and LY303366. Time-kill tests were conducted in RPMI 1640 medium buffered with morpholinepropanesulfonic acid (MOPS) to a pH of 7.0 and incubated at 35 degrees C. Prior to testing, the existence of antifungal carryover was evaluated at antifungal concentrations ranging from 1x to 16x MIC by four plating methods: direct plating of 10, 30, and 100 microl of test suspension and filtration of 30 microl of test suspension through a 0.45-microm-pore-size filter. Time-kill curves were performed with each isolate at drug concentrations equal to 2 x MIC, using a starting inoculum of approximately 10(5) CFU/ml, and incubated with or without agitation. Last, inoculum experiments were conducted over three ranges of starting inocula: 5 x 10(2) to 1 x 10(4), >1 x 10(4) to 1 x 10(6), and >1 x 10(6) to 1 x 10(8) CFU/ml. Significant antifungal carryover (>25% reduction in CFU/milliliter from the control value) was observed with amphotericin B and fluconazole; however, carryover was eliminated with filtration. Agitation did not appreciably affect results. The starting inoculum did not significantly affect the activity of fluconazole or amphotericin B; however, the activity of LY303366 may be influenced by the starting inoculum. Before antifungal time-kill curve methods are routinely employed by investigators, methodology should be scrutinized and standardized procedures should be developed.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              In vitro susceptibilities of Candida spp. to caspofungin: four years of global surveillance.

              Caspofungin is being used increasingly as therapy for invasive candidiasis. Prospective sentinel surveillance for emergence of in vitro resistance to caspofungin among invasive Candida spp. isolates is indicated. We determined the in vitro activity of caspofungin against 8,197 invasive (bloodstream or sterile-site) unique patient isolates of Candida collected from 91 medical centers worldwide from 1 January 2001 to 31 December 2004. We performed antifungal susceptibility testing according to the Clinical and Laboratory Standards Institute (CLSI, formerly NCCLS) M27-A2 method and used a 24-h prominent inhibition endpoint for determination of the MIC. Of 8,197 invasive Candida spp. isolates, species distribution was as follows: 54% Candida albicans, 14% C. glabrata, 14% C. parapsilosis, 11% C. tropicalis, 3% C. krusei, and 4% other Candida spp. Overall, caspofungin was very active against Candida (MIC50/MIC90, 0.03/0.25 microg/ml; 98.2% were inhibited at a MIC of 1 microg/ml, 12 isolates were C. parapsilosis, 6 isolates were C. guilliermondii, 2 isolates were C. rugosa, and 1 isolate each was C. albicans, C. glabrata, C. krusei, C. lusitaniae, and C. tropicalis. There was no significant change in caspofungin activity over the 4-year study period. Likewise, there was no difference in activity by geographic region. Caspofungin has excellent in vitro activity against invasive clinical isolates of Candida from centers worldwide. Our prospective sentinel surveillance reveals no evidence of emerging caspofungin resistance among invasive clinical isolates of Candida.
                Bookmark

                Author and article information

                Journal
                Braz J Microbiol
                Braz. J. Microbiol
                bjm
                bjm
                Brazilian Journal of Microbiology
                Sociedade Brasileira de Microbiologia
                1517-8382
                1678-4405
                Jan-Mar 2009
                1 March 2009
                : 40
                : 1
                : 163-169
                Affiliations
                [1 ]Instituto de Patologia Tropical e Saúde Pública da Universidade Federal de Goiás , Goiínia, GO, Brasil
                Author notes
                *Corresponding Author. Mailing address: Instituto de Patologia Tropical e Saúde Pública da Universidade Federal de Goiás. Av. Delenda resende de Melo S/N Goiânia, Goiás, Brasil. Phone: 55 62 2096127. Fax: 55 62 32611839. E-mail: rosario@ 123456iptsp.ufg.br
                Article
                S1517-838220090001000028
                10.1590/S1517-838220090001000028
                3768489
                24031337
                c09e1d77-4a07-40a2-8586-0e16eba14d8b
                © Sociedade Brasileira de Microbiologia

                All the content of the journal, except where otherwise noted, is licensed under a Creative Commons License

                History
                : 06 November 2007
                : 09 March 2008
                : 17 February 2009
                Categories
                Medical Microbiology
                Research Paper

                antifungal susceptibility,candida albicans,time kill curves

                Comments

                Comment on this article