The PICC line was removed promptly, and the tip was sent for culture. Intravenous caspofungin was started (70-mg loading dose, then 50 mg daily), and repeat blood cultures were drawn. A dilated funduscopic examination was performed; endophthalmitis was not detected.
Candida ranks fourth as a cause of nosocomial bloodstream infections in the United States, and third in the ICU.5 Risk factors for candidemia include the following: use of broad-spectrum antibiotics, parenteral nutrition, or immunosuppressive agents; neutropenia; bone marrow or solid organ transplantation; major abdominal surgery; femoral catheterization; or colonization with Candida at multiple anatomic sites.1, 13 Common species that are recovered, in order of frequency, are C albicans, C glabrata, C parapsilosis, C tropicalis, and C krusei.14 Speciation and, in some cases, susceptibility testing are important for determining which antifungal treatment is optimal. Three major classes of antifungal therapy are commonly used. The triazoles, which include fluconazole, voriconazole, and posaconazole, have excellent efficacy against C albicans, C parapsilosis, and C tropicalis, but less predictable activity against C glabrata, and fluconazole has no activity against C krusei.15 Because of its excellent oral bioavailability and ease of dosing, fluconazole is the agent of choice for C albicans, C parapsilosis, and C tropicalis. The echinocandins, which include anidulafungin, caspofungin, and micafungin, are efficacious in treating almost all Candida species. The echinocandins have been shown to have decreased in vitro activity against C parapsilosis, and are not recommended as primary therapy for infection with this organism. However, clinical studies have not shown a significant failure rate with use of echinocandins in C parapsilosis candidemia. Thus, patients started empirically on an echinocandin can complete a treatment course with this agent in the setting of C parapsilosis infection if they show an appropriate clinical response to therapy.13 Advantages of echinocandins include once-daily dosing and few drug interactions; however, echinocandins can only be administered intravenously.16 Finally, amphotericin B preparations are also effective in treating most Candida species. However, given the increased rates of side effects and drug toxicity, use of amphotericin B preparations should be limited to resource-limited environments or specific situations, such as central nervous system or endovascular disease.13 Specific antifungal therapies and dosing for commonly encountered Candida species are listed in Table 49-1.
In patients with presumptive candidemia, prompt initiation of an antifungal agent is crucial.17 In cases where there is evidence for moderate to severe disease, hemodynamic instability, or recent azole use, an echinocandin is the recommended initial empiric therapy.13 For patients with presumptive candidemia but with less severe illness and no recent azole exposure, fluconazole may be utilized as initial therapy. This particular patient did show signs of hemodynamic instability; as such, initiation of an echinocandin was appropriate.
Similar to S aureus CRBSI, prompt removal of indwelling catheters should be performed in patients with candidemia. This is because of the higher rates of failure, longer duration of therapy, and increased mortality rate associated with catheter retention.18, 19 Once the catheter is removed, the tip should be sent for microbiologic evaluation to confirm catheter-related infection. After catheter removal and initiation of antifungal therapy, repeat blood cultures need to be done to document clearance of fungemia. Given the increased risk of endophthalmitis associated with candidemia and the potentially devastating consequences of this complication, patients should have a dilated funduscopic examination within a week of fungemia.13 This has important implications for duration of treatment and therapeutic choice, as well as possible need for surgical intervention.20 Figure 49-3 illustrates the general approach to patients with CRBSI caused by Candida species.
The initial blood cultures eventually grew C albicans, and the repeat blood cultures were negative for growth.