JCM Figure table search 04
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Pfaller, M. A.
Right arrow Articles by Diekema, D. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Pfaller, M. A.
Right arrow Articles by Diekema, D. J.

 Previous Article  |  Next Article 

Journal of Clinical Microbiology, December 2003, p. 5729-5731, Vol. 41, No. 12
0095-1137/03/$08.00+0     DOI: 10.1128/JCM.41.12.5729-5731.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.

Caspofungin Activity against Clinical Isolates of Fluconazole-Resistant Candida

Michael A. Pfaller,1,2 Shawn A. Messer,1 Linda Boyken,1 Cassie Rice,1 Shailesh Tendolkar,1 Richard J. Hollis,1 and Daniel J. Diekema1,3*

Departments of Pathology,1 Epidemiology,2 Medicine, University of Iowa College of Medicine and College of Public Health, Iowa City, Iowa3

Received 10 June 2003/ Returned for modification 14 August 2003/ Accepted 1 September 2003


   ABSTRACT
Top
 Abstract
Text
 References
 
A total of 7,837 clinical isolates of Candida were tested against fluconazole, and 351 resistant (fluconazole MIC >= 64 µg/ml) isolates were identified (4% of the total tested). All fluconazole-resistant isolates were inhibited by caspofungin at concentrations that can be exceeded by standard doses (MIC at which 90% of the isolates were inhibited, 1 µg/ml; 99% of the MICs were <=2 µg/ml).


   TEXT
Top
 Abstract
 Text
References
 
Invasive candidiasis is a common and devastating infection. The annual incidence of bloodstream infections due to Candida spp. in the United States ranges from 6 to 10 infections per 100,000 persons, and the mortality attributable to such infections is estimated to be 30 to 50% (3, 4, 9, 10, 23, 29, 33; R. A. Hajjeh, 6th ASM Conf. Candida Candidasis, abstr. S-6, p. 15, 2002). The optimal treatment of candidemia requires a high index of suspicion and the early use of systemically active antifungal agents (25, 26). Although antifungal resistance among invasive isolates of Candida is not common (16-19, 25, 26), it remains a concern, especially for Candida glabrata and C. krusei (20-22, 25). Both of these species are known to express intrinsic (C. krusei) or acquired (C. glabrata) resistance to fluconazole and may also demonstrate decreased susceptibility to amphotericin B (16, 18, 20, 22, 25, 27). Thus, there is a great need for systemically active agents with fungicidal activity against species expressing resistance to fluconazole.

Caspofungin is an echinocandin with potent fungicidal activity against many species of Candida (2, 5, 6, 21). Recently, caspofungin was shown to be equivalent to (and less toxic than) amphotericin B in the treatment of patients with invasive candidiasis (13). Caspofungin is now approved for the treatment of candidemia and esophageal candidiasis as well as for salvage therapy for invasive aspergillosis (13, 31).

Caspofungin and other echinocandins have been shown to exhibit potent activity against fluconazole-resistant Candida spp. (5, 7, 12, 15). In the interest of augmenting the data on this phenomenon, we have determined the in vitro activity of caspofungin against 351 strains of fluconazole-resistant Candida spp. This set of strains constitutes the largest collection of fluconazole-resistant Candida isolates from blood or sterile sites yet tested against caspofungin.

We tested 7,837 clinical isolates of Candida obtained between 1992 and 2002 from over 160 medical centers worldwide (see Table 1). More than 85% of the isolates were from blood or a normally sterile body fluid (cerebrospinal fluid, pleural fluid, or peritoneal fluid), and each isolate represented an individual infectious episode. The isolates were identified by standard methods (32) and stored as water suspensions until they were used. Prior to testing, each isolate was passaged at least twice on potato dextrose agar (Remel, Lenexa, Kans.).


View this table:
[in this window]
[in a new window]
  		TABLE 1. Frequency of fluconazole resistancea among Candida species

 
Standard antifungal powders of caspofungin (Merck & Co., Whitehouse Station, Pa.) and fluconazole (Pfizer, Inc., New York, N.Y.) were obtained from their respective manufacturers. Stock solutions of caspofungin and of fluconazole were prepared in sterile water. Serial twofold dilutions were prepared exactly as outlined in NCCLS document M27-A2 (14). Final dilutions in RPMI 1640 medium (Sigma, St. Louis, Mo.) buffered to pH 7.0 with 0.165 M morpholinepropanesulfonic acid (MOPS) buffer (Sigma) were prepared. Aliquots (0.1 ml) of each antifungal agent at two times the final dilution were dispensed into wells of plastic microdilution trays with a Quick Spense II system (Dynatech Laboratories, Chantilly, Va.). The trays were sealed and frozen at -70°C until they were used.

Broth microdilution testing was performed as described previously (21) and in accordance with the guidelines in NCCLS document M27-A2 (14) with an inoculum concentration of (1.5 ± 1.0) x 103 cells/ml and RPMI 1640 medium buffered to pH 7.0 with MOPS. A 0.1-ml yeast inoculum was added to each well of the microdilution trays. The final concentrations of the antifungal agents were 0.007 to 8 µg/ml for caspofungin and 0.12 to 128 µg/ml for fluconazole. The trays were incubated at 35°C, and MIC end points were read after 48 h. Drug-free and yeast-free controls were included.

Following incubation, the wells were examined with a reading mirror, and the growth in each well was compared with the growth in the control well. The MIC of caspofungin was defined as the concentration resulting in complete inhibition of growth (21), and the MIC of fluconazole was defined as the lowest concentration that produced a prominent decrease in turbidity (approximately 50%) relative to that of the drug-free control well. Importantly, susceptibility testing methods for caspofungin, unlike those for fluconazole, have not been standardized yet. Our choice of complete growth inhibition as the MIC end point reflects both the fungicidal activity of caspofungin against Candida (2, 5, 6), compared to the fungistatic activity of fluconazole, and our experience with testing large numbers of organisms, including selected glucan synthesis mutants. However, the methods we used in this study may differ from future standardized methods.

The interpretive criterion for fluconazole resistance was that published by Rex et al. (24) and the NCCLS (14): an MIC of >=64 µg/ml. Isolates of C. krusei were considered resistant to fluconazole irrespective of the MIC (14). For quality control, the NCCLS-recommended strains C. krusei ATCC 6258 and C. parapsilosis ATCC 22019 were tested (1, 14).

Table 1 summarizes the frequency of fluconazole resistance among 7,837 clinical isolates of Candida spp. All 171 isolates of C. krusei were considered resistant to fluconazole, including 6 isolates for which the fluconazole MICs were <=8 µg/ml, 105 for which the MICs were 16 to 32 µg/ml, and 60 for which the MICs were >=64 µg/ml.

Among the 351 fluconazole-resistant isolates, 99% were inhibited by caspofungin at an MIC of <=2 µg/ml, and no caspofungin MICs greater than 4 µg/ml were observed (Table 2). Although in vitro susceptibility testing of caspofungin is not yet standardized, it is notable that testing by the method employed in the present study revealed that caspofungin MICs for all laboratory-derived glucan synthesis mutants of C albicans and C. krusei with in vivo resistance to caspofungin (11) were >=8 µg/ml (8 µg/ml for one mutant and >=32 µg/ml for seven mutants) (data not shown). Given that peak plasma drug concentrations in excess of 16 µg of caspofungin per ml may be achieved with a dosage of 1 mg/kg daily (8, 28), it is evident that the concentrations of the drug in plasma may exceed by fourfold or more the caspofungin MICs for fluconazole-resistant isolates of Candida (5, 6).


View this table:
[in this window]
[in a new window]
  		TABLE 2. In vitro activity of caspofungin against 351 clinical isolates of Candida spp. resistant to fluconazolea

 
Our data also demonstrate the low frequency of fluconazole resistance among bloodstream isolates of Candida spp. (Table 1). Fluconazole resistance was extremely rare among isolates of C. albicans (1%), C. tropicalis (1%), C. parapsilosis (1%), C. lusitaniae (2%), and miscellaneous Candida spp. (0 to 4%). Furthermore, only 8% of 1,432 isolates of C. glabrata exhibited resistance to fluconazole.

In summary, we have used a large international collection of clinical Candida isolates to demonstrate both a low incidence of fluconazole resistance and the excellent potency of caspofungin against those Candida strains that are fluconazole resistant.


   ACKNOWLEDGMENTS
 
We thank Linda Elliott and Shanna Duffy for excellent secretarial assistance in the preparation of the manuscript.

This study was supported in part by Merck & Company and Pfizer Pharmaceuticals.


   FOOTNOTES
 
* Corresponding author. Mailing address: Medical Microbiology Division, C606 GH, Department of Pathology, University of Iowa College of Medicine, Iowa City, IA 52242. Phone: (319) 356-8615. Fax: (319) 356-4916. E-mail: daniel-diekema{at}uiowa.edu. Back


   REFERENCES
Top
 Abstract
 Text
 References
 

  1. Barry, A. L., M. A. Pfaller, S. D. Brown, A. Espinel-Ingroff, M. A. Ghannoum, C. Knapp, R. P. Rennie, J. H. Rex, and M. G. Rinaldi. 2000. Quality control limits for broth microdilution susceptibility tests of ten antifungal agents. J. Clin. Microbiol. 38:3457-3459.[Abstract/Free Full Text]
  2. Bartizal, K., C. J. Gill, G. K. Abruzzo, A. M. Flattery, L. Kong, P. M. Scott, J. G. Smith, C. E. Leighton, A. Bouffard, J. F. Dropinski, and J. Balkovec. 1997. In vitro preclinical evaluation studies with the echinocandin antifungal MK-0991 (L-743,872). Antimicrob. Agents Chemother. 41:2326-2332.[Abstract]
  3. Diekema, D. J., S. A. Messer, A. B. Brueggemann, S. L. Coffman, G. V. Doern, L. A. Herwaldt, and M. A. Pfaller. 2002. Epidemiology of candidemia: 3-year results from the Emerging Infections and the Epidemiology of Iowa Organisms study. J. Clin. Microbiol. 40:1298-1302.[Abstract/Free Full Text]
  4. Edmond, M. B., S. E. Wallace, D. K. McClish, M. A. Pfaller, R. N. Jones, and R. P. Wenzel. 1999. Nosocomial bloodstream infections in United States hospitals: a three-year analysis. Clin. Infect. Dis. 29:239-244.[Medline]
  5. Ernst, E. J., M. E. Klepser, and M. A. Pfaller. 1999. In vitro pharmacodynamic properties of MK-0991 determined by time-kill methods. Diagn. Microbiol. Infect. Dis. 33:75-80.[CrossRef][Medline]
  6. Ernst, E. J., M. E. Klepser, and M. A. Pfaller. 2000. Postantifungal effects of echinocandin, azole, and polyene antifungal agents against Candida albicans and Cryptococcus neoformans. Antimicrob. Agents Chemother. 44:1108-1111.[Abstract/Free Full Text]
  7. Ernst, M. E., M. E. Klepser, E. J. Wolfe, and M. A. Pfaller. 1996. Antifungal dynamics of LY303366, an investigational echinocandin B analog, against Candida spp. Diagn. Microbiol. Infect. Dis. 26:125-131.[CrossRef][Medline]
  8. Groll, A. H., B. M. Gullick, R. Petraitiene, V. Petraitis, M. Candelario, S. C. Pisticelli, and T. J. Walsh. 2001. Compartmental pharmacokinetics of the antifungal echinocandin caspofungin (MK-0991) in rabbits. Antimicrob. Agents Chemother. 45:596-600.[Abstract/Free Full Text]
  9. Gudlaugsson, O., S. Gillespie, K. Lee, J. Vande Berg, S. Messer, L. Herwaldt, M. Pfaller, and D. Diekema. 2003. Attributable mortality of nosocomial candidemia, revisited. Clin. Infect. Dis. 371172-1177.
  10. Kao, A. S., M. E. Brandt, W. R. Pruitt, L. A. Conn, B. A. Perkins, D. S. Stephens, W. S. Baughman, A. L. Reingold, G. A. Rothrock, M. A. Pfaller, R. W. Pinner, and R. A. Hajjeh. 1999. The epidemiology of candidemia in two United States cities: results of a population-based active surveillance. Clin. Infect. Dis. 29:1164-1170.[CrossRef][Medline]
  11. Kurtz, M. B., G. Abruzzo, A. Flattery, K. Bartizal, J. A. Marrinan, W. Li, J. Milligan, K. Nollstadt, and C. M. Douglas. 1996. Characterization of echinocandin-resistant mutants of Candida albicans: genetic, biochemical, and virulence studies. Infect. Immun. 64:3244-3251.[Abstract]
  12. Martinez-Suarez, J. V., and J. L. Rodriguez-Tudela. 1996. In vitro activities of semisynthetic pneumocandin L-733,560 against fluconazole-resistant and -susceptible Candida albicans isolates. Antimicrob. Agents Chemother. 40:1277-1279.[Abstract]
  13. Mora-Duarte, J., R. Betts, C. Rotstein, A. L. Colombo, L. Thompson-Moya, J. Smietana, R. Lupinacci, C. Sable, N. Kartsonis, and J. Perfect. 2002. Comparison of caspofungin and amphotericin B for invasive candidiasis. N. Engl. J. Med. 347:2020-2029.[Abstract/Free Full Text]
  14. National Committee for Clinical Laboratory Standards. 2002. Reference method for broth dilution antifungal susceptibility testing of yeasts. Approved standard M27-A2, 2nd ed. National Committee for Clinical Laboratory Standards, Wayne, Pa.
  15. Nelson, P. W., M. Lozano-Chiu, and J. H. Rex. 1997. In vitro growth inhibitory activity of pneumocandins L733,560 and L-743,872 against putatively amphotericin B- and fluconazole-resistant Candida isolates: influence of assay conditions. J. Med. Vet. Mycol. 35:285-287.[Medline]
  16. Pfaller, M. A., D. J. Diekema, R. N. Jones, H. S. Sader, A. C. Fluit, R. J. Hollis, S. A. Messer, and the SENTRY Participant Group. 2001. International surveillance of bloodstream infections due to Candida species: frequency of occurrence and in vitro susceptibilities to fluconazole, ravuconazole, and voriconazole of isolates collected from 1997 through 1999 in the SENTRY Antimicrobial Surveillance Program. J. Clin. Microbiol. 39:3254-3259.[Abstract/Free Full Text]
  17. Pfaller, M. A., and D. J. Diekema. 2002. Role of sentinel surveillance of candidemia: trends in species distribution and antifungal susceptibility. J. Clin. Microbiol. 40:3551-3557.[Free Full Text]
  18. Pfaller, M. A., S. A. Messer, R. J. Hollis, R. N. Jones, and D. J. Diekema. 2002. In vitro activities of ravuconazole and voriconazole compared with those of four approved systemic antifungal agents against 6,970 clinical isolates of Candida spp. Antimicrob. Agents Chemother. 46:1723-1727.[Abstract/Free Full Text]
  19. Pfaller, M. A., S. A. Messer, L. Boyken, H. Huynh, R. J. Hollis, and D. J. Diekema. 2002. In vitro activities of 5-fluorocytosine against 8,803 clinical isolates of Candida spp.: global assessment of primary resistance using National Committee for Clinical Laboratory Standards susceptibility testing methods. Antimicrob. Agents Chemother. 46:3518-3521.[Abstract/Free Full Text]
  20. Pfaller, M. A., D. J. Diekema, S. A. Messer, L. Boyken, R. J. Hollis, R. N. Jones, and the International Fungal Surveillance Participant Group. 2003. In vitro activities of voriconazole, posaconazole, and four licensed systemic antifungal agents against Candida species infrequently isolated from blood. J. Clin. Microbiol. 41:78-83.[Abstract/Free Full Text]
  21. Pfaller, M. A., D. J. Diekema, S. A. Messer, R. J. Hollis, and R. N. Jones. 2003. In vitro activities of caspofungin compared with those of fluconazole and itraconazole against 3,959 clinical isolates of Candida spp., including 157 fluconazole-resistant isolates. Antimicrob. Agents Chemother. 47:1068-1071.[Abstract/Free Full Text]
  22. Pfaller, M. A., S. A. Messer, L. Boyken, S. Tendolkar, R. J. Hollis, and D. J. Diekema. 2003. Variation of susceptibility of bloodstream isolates of Candida glabrata to fluconazole according to patient age and geographic location. J. Clin. Microbiol. 41:2176-2179.[Abstract/Free Full Text]
  23. Rees, J. R., R. W. Pinner, R. A. Hajjeh, M. E. Brandt, and A. L. Reingold. 1998. The epidemiologic features of invasive mycotic infections in the San Francisco Bay Area, 1992-1993: results of a population-based laboratory active surveillance. Clin. Infect. Dis. 27:1138-1147.[Medline]
  24. Rex, J. H., M. A. Pfaller, J. N. Galgiani, M. S. Bartlett, A. Espinel-Ingroff, M. A. Ghannoum, M. Lancaster, F. C. Odds, M. G. Rinaldi, T. J. Walsh, and A. L. Barry for the Subcommittee on Antifungal Susceptibility Testing of the National Committee for Clinical Laboratory Standards. 1997. Development of interpretative breakpoints for antifungal susceptibility testing: conceptual framework and analysis of in vitro-in vivo correlation data for fluconazole and itraconazole. Clin. Infect. Dis. 24:235-247.[Medline]
  25. Rex, J. H., T. J. Walsh, J. D. Sobel, S. G. Filler, P. G. Pappas, W. E. Dismukes, and J. E. Edwards. 2000. Practice guidelines for the treatment of candidiasis. Clin. Infect. Dis. 30:662-678.[CrossRef][Medline]
  26. Rex, J. H., M. A. Pfaller, T. J. Walsh, V. Chaturvedi, A. Espinel-Ingroff, M. A. Ghannoum, L. L. Gosey, F. C. Odds, M. G. Rinaldi, D. J. Sheehan, and D. W. Warnock. 2001. Antifungal susceptibility testing: practical aspects and current challenges. Clin. Microbiol. Rev. 14:643-658.[Abstract/Free Full Text]
  27. Sanglard, D., F. Ischer, D. Calabrese, P. A. Majcherczyk, and J. Bille. 1999. The ATP binding cassette transporter gene CgCDR1 from Candida glabrata is involved in the resistance of clinical isolates to azole antifungal agents. Antimicrob. Agents Chemother. 43:2753-2765.[Abstract/Free Full Text]
  28. Stone, J. A., S. D. Holland, P. J. Wickersham, A. Sterrett, M. Schwartz, C. Bonfiglio, M. Hensy, G. A. Winchell, P. J. Deutsch, H. Greenberg, T. L. Hunt, and S. A. Waldman. 2002. Single- and multiple-dose pharmacokinetics of caspofungin in healthy men. Antimicrob. Agents Chemother. 46:739-745.[Abstract/Free Full Text]
  29. Trick, W. E., S. K. Fridkin, J. R. Edwards, R. A. Hajjeh, R. P. Gaynes, and the National Nosocomial Infections Surveillance System Hospitals. 2002. Secular trend of hospital acquired candidemia among intensive care unit patients in the United States during 1998-1999. Clin. Infect. Dis. 35:627-630.[CrossRef][Medline]
  30. Vazquez, J. A., M. Lynch, D. Boikov, and J. D. Sobel. 1997. In vitro activity of a new pneumocandin antifungal, L-743,872, against azole-susceptible and -resistant Candida species. Antimicrob. Agents Chemother. 41:1612-1614.[Abstract]
  31. Villanueva, A., E. G. Arathoon, E. Gotuzzo, R. S. Berman, M. J. Di Nubile, and C. A. Sable. 2001. A randomized double-blind study of caspofungin versus amphotericin for the treatment of candidal esophagitis. Clin. Infect. Dis. 33:1529-1535.[CrossRef][Medline]
  32. Warren, N. G., and K. C. Hazen. 1999. Candida, Cryptococcus, and other yeasts of medical importance, p. 1184-1199. In P. R. Murray, E. J. Baron, M. A. Pfaller, F. C. Tenover, and R. H. Yolken (ed.), Manual of clinical microbiology, 7th ed. ASM Press, Washington, D.C.
  33. Wey, S. B., M. Mori, M. A. Pfaller, R. F. Woolson, and R. P. Wenzel. 1998. Hospital acquired candidemia: attributable mortality and excess length of stay. Arch. Intern. Med. 148:2642-2645.

Journal of Clinical Microbiology, December 2003, p. 5729-5731, Vol. 41, No. 12
0095-1137/03/$08.00+0     DOI: 10.1128/JCM.41.12.5729-5731.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:


This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Pfaller, M. A.
Right arrow Articles by Diekema, D. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Pfaller, M. A.
Right arrow Articles by Diekema, D. J.

Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
Antimicrob. Agents Chemother. Clin. Microbiol. Rev.
Clin. Vaccine Immunol. ALL ASM JOURNALS