Comparison of the Bactec Fx Plus, Mycosis IC/F, Mycosis/F Lytic blood culture media and the BacT/Alert 3D FA media for detection of Candida species in seeded blood culture specimens containing therapeutic peak levels of fluconazole

J Clin Lab Anal. 2012 Nov;26(6):412-9. doi: 10.1002/jcla.21535.

Abstract

Background: The performance of Bactec Fx Plus Aerobic/F (PA), Mycosis IC/F (MF), Myco/F Lytic (ML) media and BacT/Alert 3D FA (FA) media in detecting 15 Candida isolates in blood cultures to which fluconazole had been added was investigated.

Methods: PA with resin, MF, ML media (n = 360), and FAmedia (n = 120) were tested against Candida albicans, C. tropicalis, C. parapsilosis, and C. krusei. As the peak plasma concentration after single oral doses of fluconazole 100, 200, and 400 mg was equivalent to peak level of 1.9, 4.7, and 6.7 mg/l, respectively, corresponding fluconazole was added. Time to detection (TTD) was measured.

Results: Overall TTD (mean hour ± standard deviation) for PA, FA, MF, and ML was as follows: 24.5 ± 7.3, 27.0 ± 7.5, 31.9 ± 21.3, and 37.7 ± 30.1, respectively. TTD of PA was shorter compared to other media. The effect of fluconazole was limited in PA and FA, but MF and ML showed delayed TTD. Larger inoculum size showed shorter TTDin PA and FA.

Conclusion: TTD of Bactec Fx Plus Aerobic/F was more than 2.5 hr faster among the tested media. As thus system and media are unaffected by added fluconazole, it could be used for the diagnosis of candidemia in the clinical settings including the patients who have been treated empirically with fluconazole at the time when blood cultures were drawn.

Publication types

  • Comparative Study

MeSH terms

  • Antifungal Agents / pharmacology
  • Automation, Laboratory
  • Candida / drug effects
  • Candida / isolation & purification*
  • Candidemia / blood*
  • Candidemia / microbiology*
  • Colony Count, Microbial
  • Culture Media / chemistry*
  • Fluconazole / pharmacology*
  • Humans
  • Microbiological Techniques / methods
  • Statistics, Nonparametric
  • Time Factors

Substances

  • Antifungal Agents
  • Culture Media
  • Fluconazole