Fatal Breakthrough Mucormycosis in an Acute Myelogenous Leukemia Patient while on Posaconazole Prophylaxis

From Spores to Solutions: A Comprehensive Narrative Review on Mucormycosis

Mucormycosis is an infrequent but fatal illness that mainly affects patients with uncontrolled diabetes mellitus, diabetic ketoacidosis, solid and hematologic neoplasms, organ transplantation, chronic steroid intake, prolonged neutropenia, iron overload states, neonatal prematurity, severe malnutrition, and HIV. Many cases were reported across the world recently following the COVID-19 pandemic. Recent research has led to a better understanding of the pathogenesis of the disease, and global guidelines are now available for managing this serious infection. Herein, we comprehensively review the etiological agents, pathogenesis, clinical presentations, diagnosis, and management of mucormycosis.

Advances in prophylaxis and treatment of invasive fungal infections: perspectives on hematologic diseases

Invasive fungal infections (IFIs) are common causes of mortality and morbidity in patients with hematologic diseases. Delayed initiation of antifungal treatment is related to mortality. Aspergillus sp. is the leading cause of IFI followed by Candida sp. Diagnosis is often challenging owing to variable conditions related to underlying diseases. Clinical suspect and prompt management is important. Imaging, biopsy, and non-culture-based tests must be considered together. New diagnostic procedures have been improved, including antigen-based assays and molecular detection of fungal DNA. Among hematologic diseases, patients with acute myeloid leukemia, myelodysplastic syndrome, recipients of hematopoietic stem cell transplantation are at high risk for IFIs. Antifungal prophylaxis is recommended for these high-risk patients. There are continuous attempts to achieve ideal management of IFIs. Scoring system for quality control has been developed with important recommendations of current guidelines. Higher adherence to guidelines is related to decreased mortality in IFIs.

Comparison of invasive fungal diseases between patients with acute myeloid leukemia receiving posaconazole prophylaxis and those not receiving prophylaxis: A single-center, observational, case-control study in South Korea

Posaconazole prophylaxis is effective in decreasing the incidence of invasive fungal diseases (IFDs) in patients with acute myeloid leukemia (AML). However, the use of antifungal prophylaxis varies in real-life practice, and only a small number of studies have compared the incidence of IFDs between those receiving posaconazole prophylaxis and those without prophylaxis. We compared the clinical characteristics and outcomes of IFDs between patients with AML who received posaconazole prophylaxis and those without antifungal prophylaxis.We reviewed the medical records of adult AML patients who underwent induction chemotherapy between June 2016 and October 2019 at Asan Medical Center (Seoul, South Korea), where posaconazole prophylaxis is not administered in patients with gastrointestinal symptoms that may hinder sufficient absorption of oral prophylactic agents, and in patients with abnormal liver functions considering the possible exacerbation of adverse events. Patients who received posaconazole prophylaxis for ≥7 days were included in the prophylaxis group. Clinical characteristics and outcomes including the incidence of IFDs were compared between the 2 groups.Of the 247 patients with AML who underwent induction chemotherapy, 162 (66%) received posaconazole prophylaxis and 85 (34%) did not receive any prophylaxis. The incidence of proven/probable IFD was significantly higher in the no prophylaxis group than in the prophylaxis group (9.4% [8/85] vs 2.5% [4/162], P = .03). Of the 8 cases of IFDs in the no prophylaxis group, 7 were mold infections and 1 was invasive candidiasis. Of the 4 cases of IFDs in the prophylaxis group, 3 were mold infections and 1 was invasive candidiasis. Patients with posaconazole prophylaxis less frequently received therapeutic antifungal therapy (2.5% vs 9.4%, P = .03) and had a longer median, duration from chemotherapy to antifungal therapy compared with the no prophylaxis group (18 vs 11 days, P < .01). The rate of IFD-related mortality was similar between the 2 groups (0.6% vs 0%, P > .99).Patients with AML who received posaconazole prophylaxis had a lower incidence of breakthrough IFDs compared with those who did not receive any prophylaxis. Invasive mold infection was the most common IFD regardless of antifungal prophylaxis.

In Vitro Antifungal Drug Resistance Profiles of Clinically Relevant Members of the Mucorales (Mucoromycota) Especially with the Newer Triazoles

Mucoromycoses (infections caused by members of the order Mucorales, phylum Mucoromycota [ex-Zygomycota]) are highly destructive, rapidly progressive infections, with dire prognoses especially when they occur in immunocompromised hosts. Current treatment guidelines recommend liposomal formulations of amphotericin B with adjunctive surgery as first line therapy, with the newer triazoles posaconazole or isavuconazole as alternative treatments, or as salvage therapy. Among the many organisms belonging to this order, a limited number of species in the genera Rhizopus, Mucor, Lichtheimia and Rhizomucor are responsible for most cases of human infection. Here, we present the minimum inhibitory concentration data (MICs) for amphotericin B, posaconazole, isavuconazole, itraconazole and voriconazole with a panel of over 300 isolates of the five most common agents of human infection (Lichtheimia corymbifera, Rhizopus arrhizus, R. microsporus, Rhizomucor pusillus and Mucor spp.) determined using the CLSI broth microdilution method. In agreement with previous studies, the most active antifungal drug for all Mucorales was amphotericin B, with MICs within the range that would predict susceptibility with Aspergillus fumigatus. Conversely, MICs for voriconazole against all species tested were high, and above the range associated with clinical efficacy with A. fumigatus. Interestingly, whilst isavuconazole and posaconazole MIC distributions indicated in vitro activity against some members of the Mucorales, activity was species-dependent for both agents. These data underscore the importance of accurate identification of the causative agents of mucoromycosis, coupled with antifungal susceptibility testing of individual isolates, in determining the optimal treatment of infections caused by these aggressive opportunistic human fungal pathogens.

Lichtheimia corymbifera Colonization Leading to Pulmonary Infection Can Be Prevented with Liposomal Amphotericin B in a New Murine Model

The incidence of pulmonary mucormycosis is constantly increasing, especially in hematological patients staying in high-efficiency particulate air-filtered rooms. Pulmonary inhalation of spores may occur outside the hospital, leading to invasive disease once patients received chemotherapies. We developed a new pulmonary mucormycosis mouse model mimicking the expected pathophysiology in human to study antifungal drugs. Naive mice were inoculated intratracheally with Lichtheimia corymbifera spores. After 3 days, mice received corticosteroids and cyclophosphamide and secondarily developed the disease, while only 5% of the initial inoculum was present in the lungs at day 3. Lung colonization with L. corymbifera spores in immunocompetent mice can last at least 44 days. Antifungal drug was administered the day of immunosuppression. Injection of a single 15 mg/kg of body weight dose of liposomal amphotericin B significantly improved survival and pulmonary fungal burden compared with controls, whereas 80 mg/kg oral posaconazole did not. These results show that a unique dose of liposomal amphotericin B offers a real potential decolonization treatment to prevent infection in our mouse model of L. corymbifera lung colonization followed by lung infection.

Recent advances in the understanding and management of mucormycosis

Mucormycoses were difficult-to-manage infections owing to limited diagnostic tools and therapeutic options. We review here advances in pathology understanding, diagnostic tools including computed tomography, and serum polymerase chain reaction and therapeutic options.

Catheter-Related Trichosporon asahii Bloodstream Infection in a Neutropenic Patient with Myelodysplastic Syndrome

Because primary antifungal prophylaxis is widely used for immunocompromised hosts, the incidences of unusual fungal infections have increased. Trichosporon asahii has emerged as an important life-threatening opportunistic systemic pathogen because of the increased use of cytotoxic or immunosuppressant agents, along with high mortality rates. Here, we describe a case of catheter-related T. asahii bloodstream infection with multiple septic skin nodules in both the arms and legs of the patient who was in the neutropenic period after allogeneic stem cell transplantation for myelodysplastic syndrome treated with prophylactic ciprofloxacin and itraconazole. We successfully treated her with intravenous voriconazole for more than a month without any complications. Clinicians should consider breakthrough Trichosporon infections when clinical progress in an immunocompromised patient with unexplained infection signs and symptoms does not improve despite proper treatment with antibiotics or various antifungal agents. In addition, voriconazole can be a good treatment choice for achieving better treatment results and prognosis.

Breakthrough invasive fungal diseases during voriconazole treatment for aspergillosis: A 5-year retrospective cohort study

Breakthrough invasive fungal diseases (bIFDs) during voriconazole treatment are concerning, as they are associated with high rates of mortality and pathogen distribution. To evaluate the prevalence, incidence, patient characteristics, including IFD events, and overall mortality of bIFDs during voriconazole treatment for invasive aspergillosis (IA). We retrospectively analyzed the medical records of consecutive patients who had undergone voriconazole treatment for IA and who had bIFD events between January 2011 and December 2015. Eleven bIFD events occurred in 9 patients. The prevalence and incidence of bIFDs were 2.25% (9/368) and 0.22 cases per year, respectively. Overall mortality was 44.4% (4/9). The severity of the illness and persistence of immunodeficiency, mixed infection, and low concentration of the treatment drug at the site of infection were identified as possible causes of bIFDs. Seven of 11 events (63.6%) required continued voriconazole treatment with drug level monitoring. In 4 (36.3%) cases, the treatment was changed to liposomal amphotericin B. Two cases resulted in surgical resection (18.2%). Clinicians should be aware that bIFDs during voriconazole treatment for IA can occur, and active therapeutic approaches are required in these cases.

Epidemiology and Risk Factors for Invasive Fungal Diseases among Allogeneic Hematopoietic Stem Cell Transplant Recipients in Korea: Results of "RISK" Study

Incidence, epidemiology, and risk factors of invasive fungal diseases (IFDs) in allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients can vary from different cohorts and countries. Therefore, we performed a nationwide study to establish a proper antifungal prophylaxis strategies based on risk stratifications of IFDs after all-HSCT in Korea (RISK study). This was a multicenter, retrospective, and observational study in Korea. All consecutive adult patients who received allo-HSCT in 2013 were included. The 12-month cumulative incidence of proven/probable IFDs (PP-IFDs) was calculated during the early (days 0 to 40), late (days 41 to 100), and very late (days 101 to 365) phases after allo-HSCT. Cox proportional hazard regression analysis was performed to identify risk factors for PP-IFDs at each phase. A total 521 allo-HSCT cases in 518 patients were analyzed. Overall cumulative incidence of PP-IFDs were 4.09% (95% confidence interval [CI], 2.38 to 5.81), 7.38% (95% CI, 5.09 to 9.67), and 15.36% (95% CI, 12.04 to 18.68) at the early, late and very phases, respectively. In multiple Cox regression analysis, variables were associated with PP-IFDs in each period were identified. Variables associated with early phase include underlying pulmonary diseases, underlying nonmalignant stable or chronic disease at allo-HSCT, unrelated or family mismatched donor, and prolonged neutropenia. Variables associated with the late phase include high ferritin level at the time point of allo-HSCT, use of secondary immunosuppressive agents due to refractory graft-versus-host disease (GVHD), and cytomegalovirus reactivation. For the very late phase, variables were secondary neutropenia, severe chronic GVHD, and use of TNF-alpha inhibitor for refractory GVHD. This study revealed the high cumulative incidence of IFDs in Korean allo-HSCT recipients, which have distinct risk factors in each phase after allo-HSCT. Our findings indicate that tailored antifungal prophylaxis is necessary for high-risk patients. Clinicians should consider using mold-active antifungal prophylaxis in allo-HSCT recipients who have high risks at different treatment period.

Comparison of Plasma Concentrations of Posaconazole with the Oral Suspension and Tablet in Korean Patients with Hematologic Malignancies

The posaconazole tablet formulation was developed to have improved bioavailability compared to the oral suspension. Here, we compared posaconazole plasma concentration (PPC) with the posaconazole oral suspension versus the tablet in Korean patients undergoing remission induction chemotherapy for hematologic malignancies. PPC was measured at 3, 8, and 15 days of treatment with the oral suspension (174 patients) or the tablet (40 patients). At all time-points, mean PPC was significantly higher with the tablet compared to the oral suspension. Our findings suggest that posaconazole tablets generate an optimal PPC earlier and in more patients than the oral suspension among Korean patients.

Development and application of two independent real-time PCR assays to detect clinically relevant Mucorales species

PCR-based detection of Mucorales species could improve diagnosis of suspected invasive fungal infection, leading to a better patient outcome. This study describes two independent probe-based real-time PCR tests for detection of clinically relevant Mucorales, targeting specific fragments of the 18S and the 28S rRNA genes. Both assays have a short turnaround time, allow fast, specific and very sensitive detection of clinically relevant Mucorales and have the potential to be used as quantitative tests. They were validated on various clinical samples (fresh and formalin-fixed paraffin-embedded specimens, mainly biopsies, n = 17). The assays should be used as add-on tools to complement standard techniques; a combined approach of both real-time PCR assays has 100 % sensitivity. Genus identification by subsequent sequencing is possible for amplicons of the 18S PCR assay. In conclusion, combination of the two independent Mucorales assays described in this study, 18S and 28S, detected all clinical samples associated with proven Mucorales infection (n = 10). Reliable and specific identification of Mucorales is a prerequisite for successful antifungal therapy as these fungi show intrinsic resistance to voriconazole and caspofungin.

Effect of Preexposure to Triazoles on Susceptibility and Virulence of Rhizopus oryzae

Triazole prophylaxis has become the norm in patients with hematological malignancies. Breakthrough infections caused by Mucorales during triazole prophylaxis remain a challenging problem. We found that preexposure of Rhizopus oryzae to antifungal triazoles (fluconazole, voriconazole, posaconazole, and itraconazole) did not modify the in vitro susceptibility of Rhizopus oryzae to posaconazole. In contrast, preexposure of Rhizopus to triazoles was associated with the enhanced in vitro susceptibility of R. oryzae to amphotericin B. Preexposure to posaconazole did not alter the virulence of R. oryzae in the fly model of mucormycosis.

Posaconazole for primary antifungal prophylaxis in patients with acute myeloid leukaemia or myelodysplastic syndrome during remission induction chemotherapy: a single-centre retrospective study in Korea and clinical considerations

Posaconazole was introduced as the primary antifungal prophylaxis (PAP) in acute myeloid leukaemia (AML) or myelodysplastic syndrome (MDS) patients during remission induction chemotherapy. Data on breakthrough invasive fungal infections (IFIs) from various centres are essential, as there are several considerations in treating IFIs in the posaconazole era. The aim of this study was to evaluate the effectiveness of posaconazole PAP and identify characteristics of IFIs at a single centre in Korea. We retrospectively reviewed consecutive patients with AML/MDS undergoing remission induction chemotherapy between December 2010 and November 2013. Of the 424 patients, 140 received posaconazole and 284 received fluconazole prophylaxis. The incidence of breakthrough proven/probable IFIs (15.5% vs. 2.9%, P < 0.001) and empirical antifungal treatment (EAFT) (45.8% vs. 12.9%, P < 0.001) decreased in the posaconazole group compared to the fluconazole group. In the posaconazole PAP group, two cases of breakthrough mucormycosis were noted among 13 proven/probable/possible IFI cases (15.4%). Overall and IFI-related mortality was 12.1% and 1.9% respectively. Fungus-free survival was significantly higher in the posaconazole group (74.7% vs. 87.1%, P = 0.028). Breakthrough IFIs and EAFT decreased significantly after posaconazole PAP. The benefit in fungus-free survival was noted with posaconazole PAP. Clinicians should be vigilant to identify non-Aspergillus IFIs with active diagnostic effort.