Lipid-based amphotericin in pulmonary zygomycosis: safety and efficacy of high exposure in a renal allograft recipient

Disseminated Cunninghamella elegans Infection Diagnosed by mNGS During Induction Therapy in a Child With Intermediate-risk Acute Lymphoblastic Leukemia: A Case Report and Review of Literature

We described a 14-year-old girl with acute lymphoblastic leukemia who developed disseminated mucormycosis during induction therapy. Disseminated Cunninghamella elegans infection was confirmed by histopathology, microbiological culture, and metagenomic next-generation sequencing analysis of skin tissue, blood, and cerebrospinal fluid. Subsequently, the patient received a combination of liposomal amphotericin B, posaconazole, and caspofungin for antifungal treatment, but eventually died because of severe fungal pneumonia, respiratory failure, and septic shock. Moreover, case reports of pulmonary mucormycosis in children published since 1959 were reviewed. In summary, metagenomic next-generation sequencing is an effective diagnostic method for Cunninghamella with high speed and sensitivity.

Fungal empyema thoracis in cancer patients

OBJECTIVES

Fungal empyema thoracis (FET) is a rare life-threatening infection. We sought to describe the clinical characteristics of FET in a large academic cancer center.

METHODS

We conducted a retrospective chart review of all cancer patients who had a fungal isolate from the pleural fluid culture between 1/2005 and 8/2013.

RESULTS

A total of 106 fungal isolates were identified in 97 patients. Yeasts accounted for 62% of the isolates whereas 38% were identified as molds. The most frequent pathogens were Candida spp. (58%) and Aspergillus spp. (12%). All patients with Aspergillus and 83% with Candida met criteria for proven fungal disease. Compared to the Aspergillus group, Candida FET was associated with recent abdominal or thoracic surgical procedures (44% vs. 0%, p = 0.01). Overall, 6-week mortality was high, with no significant differences between Candida and Aspergillus (31% vs. 45%, respectively [p = 0.48]). Only 1 out of 11 patients with uncommon molds died at 6 weeks, despite only 2 of them received appropriate antifungal therapy.

CONCLUSIONS

Development of FET carries a high mortality in cancer patients. A history of a recent surgical procedure is a risk factor for FET due to Candida. Isolation of uncommon molds is likely to represent a contamination of the pleural fluid.

Lipid formulations of amphotericin B as first-line treatment of zygomycosis

Zygomycosis is a difficult to treat and frequently fatal infection affecting immunocompromised and, rarely, immunocompetent patients. The early diagnosis and immediate initiation of treatment with an antifungal agent in combination with surgical intervention has proved critical for the favourable outcome of the disease. Few antifungal agents are available for treatment. Amphotericin B (AmB) deoxycholate has been the drug of choice for many years and is usually given at high daily doses which can result in renal toxicity. Currently, lipid formulations of AmB (liposomal AmB (L-AmB), AmB lipid complex (ABLC), AmB colloidal dispersion (ABCD)), mainly L-AmB, rather than conventional AmB have become the standard therapy. The rationale behind the use of lipid formulations is that they decrease the nephrotoxicity associated with longterm AmB use. Although there is a developing consensus that high doses of lipid formulations of AmB should be the antifungal therapy of choice for all patients with zygomycosis, until now there have been no data available with which to define the appropriate dose. The duration of therapy remains an unresolved issue, regarding both lipid formulations of AmB as well as sequential or combination treatments consisting of lipid formulations of AmB with posaconazole, a drug which has now emerged as a new therapeutic option.

Pseudohyperphosphatemia associated with high-dose liposomal amphotericin B therapy

BACKGROUND

Acute increases in serum inorganic phosphorus (Pi) up to 4.75 mmol/l in the absence of hypocalcemia and tissue deposition of calcium phosphate were noted in 3 patients receiving liposomal amphotericin B (L-AMB). We investigated L-AMB as a possible cause of pseudohyperphosphatemia.

METHODS

Serum samples from the index patient were analyzed for Pi content by our laboratory's primary analyzer (Synchron LX20) and by an alternate analyzer (Vitros). Clear and lipemic serum pools, and normal saline, were spiked with L-AMB and analyzed by the LX20 Pi method. Ultrafiltration studies were performed on patient and spiked sera.

RESULTS

Increased Pi values were obtained only from the LX20 analyzer. There was a direct linear relationship between the concentration of L-AMB in the spiked samples and the LX20 Pi results, indicating a 0.9 mmol/l Pi increase for every 100 mg/l increase in L-AMB. Ultrafiltration normalized the Pi results.

CONCLUSION

Serum Pi results may be falsely increased in patients receiving L-AMB when measured by the LX20 analyzer. This novel cause of pseudohyperphosphatemia is due to interference of L-AMB with the method and is corrected by ultrafiltration of the specimen. Since the LX20 analyzer is widely used by the clinical laboratories clinicians and laboratory personnel should recognize this interference in order to avoid unnecessary diagnostic procedures and interventions.

Outcomes of invasive zygomycosis infections in renal transplant recipients

Zygomycosis is an infrequent and difficult-to-treat fungal infection that is found in patients with underlying immunocompromised states. The advent of the lipid amphotericin B products has allowed for treatment with higher doses of therapy and less systemic toxicity. We reviewed the outcomes of 6 renal transplant recipients diagnosed with biopsy-proven invasive zygomycosis who received amphotericin B lipid complex (ABLC) in doses greater than 5 mg/kg between 2000 and 2004. All 6 patients had baseline diabetes mellitus, were receiving immunosuppressive agents, and subsequently underwent concomitant surgery. Three of the 6 patients that survived had undergone significant surgical debridement, reduction of their immunosuppression to minimal prednisone, and received prolonged course of ABLC at 10 mg/kg/day. All survivors lost graft function during the course of their therapy. The 3 patients who died all had delays in diagnosis of their disease and subsequent surgical and appropriate medical therapy. Therefore, in renal transplant recipients the early diagnosis of invasive zygomycosis is imperative along with early therapy with surgical debridement, reduced immunosuppression, and the use of high doses of ABLC.

Zygomycosis: the re-emerging fungal infection

Invasive fungal infections are major medical complications in immunocompromised patients. The recent rise in the incidence of cancer and the increased use of newer medical treatment modalities, including organ transplantations, have resulted in growing numbers of highly immunosuppressed individuals. Although aspergillosis and candidiasis are among the most common invasive mycoses in such patients, there is evidence that the incidence of infectious diseases caused by Zygomycetes has risen significantly over the past decade. Patients with diabetes, malignancies, solid organ or bone marrow transplants, or iron overload and those receiving immunosuppressive agents, deferoxamine therapy, or broad-spectrum antimicrobial drugs are at highest risk for zygomycosis. This review details the emergence and importance of zygomycosis in current clinical practice and its manifestations and management. The etiologic species, pathogenesis and risk factors for zygomycosis are reviewed and updated. The clinical spectrum of zygomycosis is now broader, and it can be difficult to distinguish between mucormycosis and enthomophthoramycosis, both of which can manifest as disease ranging from a superficial infection to an angioinvasive infection with high mortality. Finally, the three-part treatment strategy (antifungal drugs, surgery, control of underlying diseases) is reviewed. Lipid formulations of amphotericin B are the antifungal agents of choice for treatment of zygomycosis. A novel antifungal triazole, posaconazole, has been developed and may become approved for treatment of zygomycosis. The clinical experience with adjunctive treatments like colony-stimulating factors, interferon-gamma, and hyperbaric oxygen therapy is still limited.