Antifungal activity of posaconazole compared with fluconazole and amphotericin B against yeasts from oropharyngeal candidiasis and other infections

Alfonso-Javier Carrillo-Muñoz1,*, Guillermo Quindós2, Maite Ruesga2, Rocío Alonso2, Oscar del Valle3, Juan Manuel Hernández-Molina4, Paul McNicholas5, David Loebenberg5 and Patricia Santos6

1 Departamento de Microbiología, ACIA, PO Box 10178, E-08080 Barcelona; 2 Departamento de Inmunología, Microbiología y Parasitología, Facultad de Medicina, Universidad del País Vasco, Bilbao; 3 Servicio de Microbiología, Hospital Vall d'Hebrón, Barcelona; 4 Servicio de Microbiología, Hospital La Inmaculada, Huércal-Overa, Almería, Spain; 5 Schering-Plough Research Institute, Kenilworth, NJ, USA; 6 Hospital de Pediatría Pablo Garrahan, Buenos Aires, Argentina


* Corresponding author. Tel/Fax: +34-93-4297120; Email: acarrillo{at}ya.com

Received 3 March 2004; returned 22 March 2004; revised 21 November 2004; accepted 15 December 2004


    Abstract
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Objectives: The in vitro antifungal activity of posaconazole was compared with that of fluconazole and amphotericin B.

Materials and methods: A microdilution method (M27-A2) was used with 331 clinical yeast isolates.

Results: The geometric mean MICs of posaconazole, fluconazole and amphotericin B were 0.16, 0.91 and 0.15 mg/L, respectively. Posaconazole was markedly more active than fluconazole and was active against 9/11 fluconazole-resistant Candida albicans, and five Candida glabrata had an MIC of posaconazole of 16 mg/L.

Conclusions: These data indicate that posaconazole is a potentially effective antifungal agent for the treatment of mycoses caused by yeasts.

Keywords: susceptibility , opportunistic , Candida


    Introduction
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Posaconazole is a novel triazole with broad-spectrum in vitro activity against pathogenic fungi, including Aspergillus spp., Candida spp., Cryptococcus spp. and Histoplasma spp.120 Posaconazole has also proven to be efficacious in a wide variety of animal models of candidiasis, disseminated aspergillosis, pulmonary histoplasmosis, coccidioidomycosis and disseminated fusariosis.2124 In the clinic, posaconazole has been effective in the treatment of human oropharyngeal candidiasis, invasive aspergillosis, candidiasis and fusariosis, and posaconazole is unique among the azoles in having activity in the treatment of zygomycosis.2126

The purpose of this study was to compare the in vitro antifungal activity of posaconazole with that of fluconazole and amphotericin B gainst a collection of 331 clinically significant yeasts using the standardized microdilution method as described in the NCCLS document M27-A2.27


    Materials and methods
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
The isolates were cultured from patients, none of whom had received posaconazole therapy. The Candida albicans strains were isolated from oropharyngeal samples from HIV-positive patients and the others were from urine, skin and nail sources. The strains included C. albicans (n = 191) (124 C. albicans serotype A and 28 C. albicans serotype B, the remaining 39 isolates were not serotyped), Candida tropicalis (n = 42), Candida glabrata (n = 32), Candida lusitaniae (n = 30), Candida parapsilosis (n = 20) and Candida famata (n = 16). In addition, strains of C. albicans (ATCC 1001, ATCC 90028), C. glabrata (ATCC 90030) and C. lusitaniae (ATCC 200950, ATCC 200951, ATCC 200952, ATCC 200953, ATCC 200954, ATCC 64125, ATCC 66035, ATCC 42720) were also tested as internal and external control strains, and in the same way the C. albicans Mont-R strain was included (provided by the University of Montpellier, France), a fluconazole-resistant isolate. The NCCLS approved quality control strains (Candida krusei ATCC 6258 and C. parapsilosis ATCC 22019) were also tested. Control strains were tested in each susceptibility test.

All isolates were stored in sterile distilled water. Before testing, the isolates were subcultured on Sabouraud glucose agar (Biolife, Milan, Italy) at 35°C for 24 h to ensure the inoculum's purity and viability. Antifungal agents were obtained from their respective manufacturers: posaconazole, Schering-Plough Research Institute (Kenilworth, NJ, USA); fluconazole, Pfizer (Sandwich, UK); and amphotericin B, Bristol-Myers Squibb (Princeton, NJ, USA). Amphotericin B and posaconazole were solubilized in DMSO (UVASOL DMSO; Merck, Darmstadt, Germany), and fluconazole was solubilized in water.

Susceptibility testing was carried out according to the NCCLS document M27-A2.27 RPMI 1640 (with glutamine and without bicarbonate) buffered with MOPS (0.165 M) (Sigma Chemical Co., St Louis, MO, USA) was used. The pH of RPMI 1640 was adjusted to pH 7.0 at 25°C using sodium hydroxide (Panreac, Madrid, Spain). The medium was filter-sterilized (Steritop-GP Units, Millipore, Billerica, MA, USA) and stored at 2–8°C. Antifungal drug concentrations ranged from 0.25 to 256 mg/L for fluconazole, and 0.016–16 mg/L for posaconazole and amphotericin B. A strain was considered resistant to fluconazole and amphotericin B if the MICs were ≥ 64 and > 1 mg/L, respectively. A strain was considered to be fluconazole-susceptible-dose-dependent when the MIC was 16–32 mg/L. The MIC50 s and MIC90 s were calculated as the concentrations of antifungal that were able to inhibit 50% and 90% of the isolates, respectively.


    Results
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
The in vitro susceptibility results obtained for posaconazole, fluconazole and amphotericin B against the quality control and reference strains are within the ranges that are considered normal for these strains in our internal and the external antifungal susceptibility tests.28 Table 1 shows the in vitro susceptibility values observed for the clinical strains; shown are the MIC50s and MlC90s, as well as the geometric mean MIC values and the range of MIC values.


View this table:
[in this window]
[in a new window]
 
Table 1. Geometric mean MIC (GM), MIC range, MIC50 and MIC50 (mg/L) of amphotericin B, fluconazole and posaconazole for 331 Candida isolates

 
The posaconazole geometric mean MIC was 0.16 mg/L, whereas for fluconazole and amphotericin B, the geometric mean MICs were 0.91 and 0.15 mg/L, respectively. Also, the MIC50 and MlC90 values of posaconazole and amphotericin B (0.125 and 0.5 mg/L, respectively) were lower than the corresponding values of fluconazole (0.5 and 16 mg/L, respectively). The MIC50 and MIC90 values of posaconazole and amphotericin B inhibited 82.8% and 90% of the tested strains against posaconazole and 56.2% and 93.4% against amphotericin B. Posaconazole was similar or slightly superior to amphotericin B against all isolates. Compared with fluconazole, posaconazole was either similar or superior against all isolates. The incidence of fluconazole-susceptible-dose-dependent and fluconazole-resistant isolates was 12.1% and 5.1%, respectively; the mean fluconazole MIC for these isolates was > 16 mg/L. Only five of these isolates had a posaconazole MIC of 16 mg/L. None of the isolates in our collection had an MIC > 2 mg/L of amphotericin B.


    Discussion
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
In this study, we demonstrate that posaconazole has a superior in vitro activity profile when compared with fluconazole. Previous studies reported MIC50 values of posaconazole that differed from ours by 1–3 dilutions.1 This could be due to geographical and source variations in patterns of in vitro susceptibility, but also to the spectrophotometer readings which may at least partly explain the differences in the reported MIC90s. Other authors have found similar MICs of posaconazole for pathogenic yeasts although some interspecies differences have been observed.4,18 The in vitro antifungal activity of posaconazole reported here is greater than that reported by Ostrosky-Zeichner et al.1 Of particular note is our finding that posaconazole has excellent activity against C. tropicalis; this contrasts with data from Ostrosky-Zeichner et al. who reported an MIC90 of 1 mg/L. In contrast, the posaconazole MIC90 for oropharyngeal C. albicans isolates was 1 mg/L; this is higher than the value (0.13 mg/L) reported by Ostrosky-Zeichner et al.1 These pathogens, together with other Candida, Cryptococcus and Aspergillus species are responsible for most of the cases of disseminated mycoses in humans. Based on the findings of this study, we would predict that posaconazole would be active against the agents responsible for the majority of moderate and severe mycoses detected in Spain. In particular, the majority of the fluconazole-susceptible-dose-dependent and fluconazole-resistant strains were susceptible to posaconazole. Posaconazole was also highly effective against species such as C. parapsilosis and C. famata and other genera not included in our study against which other promising new antifungal drugs, such as the echinocandins, do not seem to be effective in vitro.7 However, further in vivo tests will be required to confirm these findings.


    References
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
1 . Ostrosky-Zeichner, L., Rex, J. H., Pappas, P. G. et al. (2003). Antifungal susceptibility survey of 2,000 bloodstream Candida isolates in the United States. Antimicrobial Agents and Chemotherapy 47, 3149–54.[Abstract/Free Full Text]

2 . Barchiesi, F., Schimizzi, A. M., Caselli, F. et al. (2001). Activity of the new antifungal triazole, posaconazole, against Cryptococcus neoformans. Journal of Antimicrobial Chemotherapy 48, 769–73.[Abstract/Free Full Text]

3 . Cacciapuoti, A., Loebenberg, D., Corcoran, E. F., Jr et al. (2000). In vitro and in vivo activities of SCH 56592 (posaconazole), a new triazole antifungal agent, against Aspergillus and Candida. Antimicrobial Agents and Chemotherapy 44, 2017–22.[Abstract/Free Full Text]

4 . Cantón, E., Pemán, J., Orero, A. et al. (2002). In vitro activity of posaconazole against yeasts isolated in blood cultures. Revista Española Quimioterapia 15, 341–5.

5 . Carrillo, A. J. & Guarro, J. (2001). In vitro activities of four novel triazoles against Scedosporium spp. Antimicrobial Agents and Chemotherapy 45, 2151–3.[Abstract/Free Full Text]

6 . Connolly, P., Wheat, L. J., Schnizlein-Bick, C. et al. (2000). Comparison of a new triazole, posaconazole, with itraconazole and amphotericin B for treatment of histoplasmosis following pulmonary challenge in immunocompromised mice. Antimicrobial Agents and Chemotherapy 44, 2604–8.[Abstract/Free Full Text]

7 . Espinel-Ingroff, A. (1998). 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. Journal of Clinical Microbiology 36, 2950–6.[Abstract/Free Full Text]

8 . Galgiani, J. N. & Lewis, M. L. (1997). In vitro studies of activities of the antifungal triazoles SCH56592 and itraconazole against Candida albicans, Cryptococcus neoformans, and other pathogenic yeasts. Antimicrobial Agents and Chemotherapy 41, 180–3.

9 . González, G. M., Tijerina, R., Najvar, L. K. et al. (2002). In vitro and in vivo activities of posaconazole against Coccidioides immitis. Antimicrobial Agents and Chemotherapy 46, 1352–6.[Abstract/Free Full Text]

10 . Law, D., Moore, C. B. & Denning, D. W. (1997). Activity of SCH 56592 compared with those of fluconazole and itraconazole against Candida spp. Antimicrobial Agents and Chemotherapy 41, 2310–1.[Abstract]

11 . Marco, F., Pfaller, M. A., Messer, S. A. et al. (1998). In vitro activity of a new triazole antifungal agent, SCH 56592, against clinical isolates of filamentous fungi. Mycopathologia 141, 73–7.[CrossRef][ISI][Medline]

12 . Pfaller, M. A., Diekema, D. J., Messer, S. A. et al. (2003). In vitro activities of voriconazole, posaconazole, and four licensed systemic antifungal agents against Candida species infrequently isolated from blood. Journal of Clinical Microbiology 41, 78–83.[Abstract/Free Full Text]

13 . Pfaller, M. A., Messer, S. A., Hollis, R. J. et al. (2002). Antifungal activities of posaconazole, ravuconazole, and voriconazole compared to those of itraconazole and AMB against 239 clinical isolates of Aspergillus spp. and other filamentous fungi: report from SENTRY Antimicrobial Surveillance Program, 2000. Antimicrobial Agents and Chemotherapy 46, 1032–7.[Abstract/Free Full Text]

14 . Pfaller, M. A., Messer, S. A., Hollis, R. J. et al. (2001). In vitro activities of posaconazole (SCH 56592) compared with those of itraconazole and FLZ against 3,685 clinical isolates of Candida spp. and Cryptococcus neoformans. Antimicrobial Agents and Chemotherapy 45, 2862–4.[Abstract/Free Full Text]

15 . Pfaller, M. A., Messer, S. A., Hollis, R. J. et al. (1998). In vitro susceptibilities of Candida bloodstream isolates to the new triazole antifungal agents BMS-207147, Sch 56592, and voriconazole. Antimicrobial Agents and Chemotherapy 42, 3242–4.[Abstract/Free Full Text]

16 . Pfaller, M. A., Messer, M. A. & Jones, R. N. (1997). Activity of a new triazole, SCH 56592, compared with those of four other antifungal agents tested against clinical isolates of Candida spp. and Saccharomyces cerevisiae. Antimicrobial Agents and Chemotherapy 41, 233–5.[Abstract]

17 . Quindós, G., Carrillo-Muñoz, A. J., Arévalo, M. P. et al. (2000). Susceptibility of Candida dubliniensis to current and new antifungal agents. Chemotherapy 46, 395–401.[CrossRef][ISI][Medline]

18 . Rubio-Calvo, M. C., Gil, J., Ramírez De Ocariz, I. et al. (2003). In vitro activity of fluconazole, voriconazole and posaconazole against Candida spp. Revista Española Quimioterapia 16, 227–32.

19 . Sugar, A. M. & Liu, X. P. (1996). In vitro and in vivo activities of SCH 56592 against Blastomyces dermatitidis. Antimicrobial Agents and Chemotherapy 40, 1314–6.[Abstract]

20 . Graybill, J. R., Bocanegra, R., Najvar, L. K. et al. (1998). SCH56592 treatment of murine invasive aspergillosis. Journal of Antimicrobial Chemotherapy 42, 539–42.[Abstract]

21 . Kirkpatrick, W. R., McAtee, R. K., Fothergill, A. W. et al. (2000). Efficacy of SCH56592 in a rabbit model of invasive aspergillosis. Antimicrobial Agents and Chemotherapy 44, 780–2.[Abstract/Free Full Text]

22 . Lozano-Chiu, M., Arikan, S., Paetznick, V. L. et al. (1999). Treatment of murine fusariosis with SCH 56592. Antimicrobial Agents and Chemotherapy 43, 589–91.[Abstract/Free Full Text]

23 . Lutz, J. E., Clemons, K. W., Aristizabal, B. H. et al. (1997). Activity of the triazole SCH 56592 against disseminated murine coccidioidomycosis. Antimicrobial Agents and Chemotherapy 41, 1558–61.[Abstract]

24 . Sponsel, W. E., Graybill, J. R., Nevarez, H. L. et al. (2002). Ocular and systemic posaconazole (SCH-56592) treatment of invasive Fusarium solani keratitis and endophthalmitis. British Journal Ophthalmology 86, 829–30.[CrossRef]

25 . Mellinghoff, I. K., Winston, D. J., Mukwaya, G. et al. (2002). Treatment of Scedosporium apiospermum brain abscesses with posaconazole. Clinical Infectious Diseases 34, 1648–50.[CrossRef][ISI][Medline]

26 . Dannaoui, E., Meis, J. F., Loebenberg, D. et al. (2003). Activity of posaconazole in treatment of experimental disseminated zygomycosis. Antimicrobial Agents and Chemotherapy 47, 3647–50.[Abstract/Free Full Text]

27 . National Committee for Clinical Laboratory Standards (2002). Reference Method for Broth Dilution Antifungal Susceptibility Testing of Yeasts—Second Edition: Approved Standard M27-A2. NCCLS, Wayne, PA, USA.

28 . Barry, A. L., Pfaller, M. A., Brown, S. D. et al. (2000). Quality control limits for broth microdilution susceptibility tests of ten antifungal agents. Journal of Clinical Microbiology 38, 3457–9.[Abstract/Free Full Text]





This Article
Abstract
FREE Full Text (PDF)
All Versions of this Article:
55/3/317    most recent
dki022v1
Alert me when this article is cited
Alert me if a correction is posted
Services
Email this article to a friend
Similar articles in this journal
Similar articles in ISI Web of Science
Similar articles in PubMed
Alert me to new issues of the journal
Add to My Personal Archive
Download to citation manager
Search for citing articles in:
ISI Web of Science (1)
Disclaimer
Request Permissions
Google Scholar
Articles by Carrillo-Muñoz, A.-J.
Articles by Santos, P.
PubMed
PubMed Citation
Articles by Carrillo-Muñoz, A.-J.
Articles by Santos, P.