From the Guidelines
For the treatment of Candida tropicalis, an echinocandin, such as anidulafungin, is recommended as initial therapy due to its broad fungicidal activity and favorable safety profile, with a potential step-down to fluconazole once the patient is clinically stable and the infecting organism is susceptible 1.
Treatment Approach
The approach to treating Candida tropicalis involves considering the severity of illness, relevant co-morbidities, and evidence of involvement of critical organs. Given the potential for high mortality rates associated with candidemia, early initiation of effective antifungal therapy and source control is critical 1.
Echinocandins as First-Line Therapy
Echinocandins, including anidulafungin, micafungin, and caspofungin, demonstrate significant fungicidal activity against most Candida species, including C. tropicalis. These agents have shown success in approximately 70%–75% of patients in randomized, comparative clinical trials 1. Their use as initial therapy is favored due to concerns about fluconazole resistance and their favorable safety profile.
Step-Down Therapy
A recent open-label noncomparative trial assessed outcomes of patients treated with anidulafungin for at least 5 days followed by step-down therapy to oral fluconazole or voriconazole when clinically stable and blood cultures had become negative 1. This approach is supported for patients who have improved clinically, have documented clearance of Candida from the bloodstream, and are infected with an organism susceptible to fluconazole or voriconazole.
Considerations for Fluconazole Use
Fluconazole remains an option for patients who are hemodynamically stable, have had no previous exposure to azoles, and do not belong to a group at high risk for C. glabrata infection 1. However, its use should be guided by susceptibility testing due to the increasing resistance among Candida species.
Role of Other Antifungals
Voriconazole and posaconazole have excellent in vitro activity against most Candida species but are typically reserved for specific cases, such as fluconazole-resistant isolates or when transitioning from an echinocandin or AmB to oral therapy 1. Amphotericin B, particularly lipid formulations, is considered for cases with a history of intolerance to echinocandins and/or azoles, refractory infections, or suspicion of infection due to non-Candida yeasts.
Monitoring and Duration of Therapy
Follow-up blood cultures every day or every other day until clearance of Candida from the bloodstream is recommended to establish the appropriate duration of antifungal therapy 1. Therapy should continue for at least 14 days following documented clearance and resolution of signs and symptoms attributable to infection. A dilated funduscopic examination is also advised within the first week after initiation of antifungal therapy to detect ocular involvement.
From the FDA Drug Label
Antimicrobial Activity Fluconazole has been shown to be active against most isolates of the following microorganisms both in vitro and in clinical infections ... Candida tropicalis Antimicrobial Activity Voriconazole has been shown to be active against most isolates of the following microorganisms, both in vitro and in clinical infections ... Candida tropicalis
- Candida tropicalis is susceptible to fluconazole and voriconazole 2 3.
- Both fluconazole and voriconazole have been shown to be active against Candida tropicalis in vitro and in clinical infections.
From the Research
Overview of Candida tropicalis
- Candida tropicalis is a species of Candida that can cause infections in humans, particularly in hospitalized patients 4.
- It is the fourth most common cause of candidaemia in hospitalized patients and is associated with high mortality 4.
Antifungal Treatment
- Fluconazole is a commonly used antifungal drug, but its effectiveness against C. tropicalis can be limited, especially in cases of fluconazole-resistant isolates 5, 6.
- Echinocandins, such as micafungin, have been shown to be effective against C. tropicalis, including biofilm-related infections 4, 7.
- Other antifungal drugs, such as voriconazole, posaconazole, and amphotericin B, have also been shown to be effective against C. tropicalis 8, 7.
Resistance and Susceptibility
- C. tropicalis can develop resistance to antifungal drugs, including fluconazole and echinocandins 5, 7.
- The susceptibility of C. tropicalis to antifungal drugs can vary depending on the specific isolate and the drug being used 8, 7.
- Combination therapy with multiple antifungal drugs may be effective in treating C. tropicalis infections, especially in cases of resistance or susceptibility to a single drug 6.
Clinical Implications
- C. tropicalis infections can be serious and life-threatening, particularly in hospitalized patients or those with compromised immune systems 4.
- Effective treatment of C. tropicalis infections requires careful selection of antifungal drugs and consideration of the potential for resistance and susceptibility 5, 7.
- Further research is needed to develop new and effective treatments for C. tropicalis infections, including those caused by resistant or susceptible isolates 4, 6.