Fatal Candida tropicalis fungaemia in a leukaemic patient receiving fluconazole prophylaxis

Breakthrough invasive fungal infections: Who is at risk?

The epidemiology of invasive fungal infections (IFIs) in immunocompromised individuals has changed over the last few decades, partially due to the increased use of antifungal agents to prevent IFIs. Although this strategy has resulted in an overall reduction in IFIs, a subset of patients develop breakthrough IFIs with substantial morbidity and mortality in this population. Here, we review the most significant risk factors for breakthrough IFIs in haematology patients, solid organ transplant recipients, and patients in the intensive care unit, focusing particularly on host factors, and highlight areas that require future investigation.

Fatal candidemia caused by azole-resistant Candida tropicalis in patients with hematological malignancies

Candida tropicalis is one of the most important Candida species causative of candidemia that is isolated from the blood of patients with hematological malignancies. Candidemia caused by C. tropicalis is known to be highly virulent in neutropenic patients. C. tropicalis has been shown to be favorably sensitive to azole agents in general. Here we discuss 5 cases of candidemia caused by C. tropicalis in patients with hematological malignancies in our unit, and we note that 4 isolates were resistant to azole agents, including fluconazole, itraconazole, and voriconazole. In addition, 2 patients developed breakthrough candidemia caused by C. tropicalis while receiving prophylaxis with azole agents. Interestingly, 2 of the 4 patients with azole-resistant C. tropicalis isolates had never received any antifungal drugs. We also examined the susceptibilities of C. tropicalis to antifungal agents, using 39 non-blood isolates detected from 2003 to 2009. Around 40 % of the isolates were resistant to azole agents, and all of them were highly sensitive to amphotericin B and micafungin. The resistance to azoles was not associated with previous exposure to those agents. In our unit, 2 of the 4 cases of candidemia caused by azole-resistant C. tropicalis resulted in a poor prognosis. These findings suggested that empirical therapeutic strategies for candidemia should be modified based on the local antifungal resistance pattern.

Invasive fungal disease in patients treated for newly diagnosed acute leukemia

Invasive fungal disease (IFD) is a significant cause of morbidity and mortality in patients undergoing treatment for acute leukemia (AL). Antifungal prophylactic strategies are associated with significant toxicities and cost. We performed a retrospective study of the incidence and risk factors for IFD among patients newly diagnosed with and treated for AL between January 1, 2004 and July 1, 2006. Patient follow up concluded January 1, 2007. Among 231 patients with newly diagnosed AL, 31 (13.4%) developed IFD by the end of follow up, 24 (10.4%) of whom developed IFD within the first 100 days after diagnosis of AL. The cumulative probability of developing IFD was 5.9% by 30 days and 11.1% at 100 days after AL diagnosis. Patients who had persistent leukemia after an initial course of induction chemotherapy were significantly more likely to develop IFD than those who did not have evidence of persistent leukemia (14/65 (21.5%) vs. 15/148 (10.1%), P = 0.03). In a time-dependent Cox model, the adjusted hazard ratio for developing IFD within the first 100 days of AL diagnosis based on the number of days of neutropenia in that period was 4.85 (95% confidence interval: 1.52, 15.4). Those patients with more days of neutropenia in the first 100 days after AL diagnosis, such as those who did not achieve remission after a first course of induction chemotherapy, were more likely to develop IFD.

Risk Factors for Candida tropicalis fungemia in patients with cancer

The risk factors for and presentation of Candida tropicalis fungemia, in comparison with those of Candida albicans, have been incompletely characterized. We compared 43 cases of C. tropicalis fungemia with 148 cases of C. albicans fungemia. In univariate analysis, patients with C. tropicalis fungemia were more likely to have leukemia (P=.0006), prolonged neutropenia (P=.03), and a positive blood culture for more days (P=.02). The 2 groups did not differ with regard to baseline Acute Physiology and Chronic Health Evaluation (APACHE) II score, frequency of catheter-associated fungemia, or response to antifungals. In multivariate analysis, patients with C. tropicalis fungemia were more likely to have leukemia (P=.02), previous neutropenia (P=.002), and a longer stay in the intensive care unit during the infectious episode (P=.01). Also, the response of the breakthrough C. tropicalis fungemia was lower (P=.05). In conclusion, the host determinants associated with susceptibility to C. tropicalis are leukemia and prolonged neutropenia.

The changing spectrum of candidemia in oncology patients: therapeutic implications

Infections caused by Candida spp. are frequent and serious in oncology patients. Over the past decade, the introduction of azole antifungals as prophylactic agents, and other factors have caused a shift in the species of Candida that cause infection. During the period under review (June 1999 to June 2000), several studies have been reported that confirm the impact of antifungal prophylaxis and the emergence of non-albicans Candida spp. as pathogens. Moreover, laboratory studies to determine the antifungal susceptibilities and virulence properties of non-albicans Candida spp. have enabled the formation of microbe-specific management strategies. More of these studies will be necessary as we enter an age in which multiple antifungal compounds will become available for clinical use.