Is there an association between zinc and COVID-19-associated mucormycosis? Results of an experimental and clinical study.

BACKGROUND: The enormous increase in COVID-19-associated mucormycosis (CAM) in India lacks an explanation. Zinc supplementation during COVID-19 management is speculated as a contributor to mucormycosis. We conducted an experimental and clinical study to explore the association of zinc and mucormycosis. METHODS: We inoculated pure isolates of Rhizopus arrhizus obtained from subjects with CAM on dichloran rose Bengal chloramphenicol (DRBC) agar enriched with (three different concentrations) and without zinc. At 24 h, we counted the viable colonies and measured the dry weight of colonies at 24, 48 and 72 h. We also compared the clinical features and serum zinc levels in 29 CAM cases and 28 COVID-19 subjects without mucormycosis (controls). RESULTS: We tested eight isolates of R arrhizus and noted a visible increase in growth in zinc-enriched media. A viable count percentage showed a significantly increased growth in four of the eight isolates in zinc-augmented DRBC agar. A time- and concentration-dependent increase in the mean fungal biomass with zinc was observed in all three isolates tested. We enrolled 29 cases of CAM and 28 controls. The mean serum zinc concentration was below the reference range in all the subjects and was not significantly different between the cases and controls. CONCLUSIONS: Half of the R arrhizus isolates grew better with zinc enrichment in vitro. However, our study does not conclusively support the hypothesis that zinc supplementation contributed to the pathogenesis of mucormycosis. More data, both in vitro and in vivo, may resolve the role of zinc in the pathogenesis of CAM.

Antifungal combinations in Mucorales: A microbiological perspective.

Mucormycosis mostly affects immunocompromised patients and is associated with a high morbidity and mortality despite currently available treatments. In that context, combination therapy might be the key to a better outcome for these patients. Purpose of this review is to summarise and to discuss the current combination data obtained in vitro, in vivo in animal models of mucormycosis, and in patients. In vitro combination studies showed that most of the interactions between antifungal drugs were indifferent, even though that some synergistic interactions were achieved for the combination of echinocandins with either azoles or amphotericin B. Importantly, antagonism was never observed. Animal models of mucormycosis focused on infections caused by Rhizopus arrhizus, neglecting most other species responsible for human disease. In these experimental animal models, no strong interactions have been demonstrated, although a certain degree of synergism has been reported in some instances. Combinations of antifungals with non-antifungal drugs have also been largely explored in vitro and in animal models and yielded interesting results. In patients with ketoacidosis and rhino-orbito-cerebral infection, combination of polyene with caspofungin was effective. In contrast, despite promising experimental data, adjunctive therapy with the iron chelator deferasirox was unfavourable and was associated with a higher mortality than monotherapy with liposomal amphotericin B. More combinations have to be tested in vitro and a much larger panel of Mucorales species has to be tested in vivo to give a valuable statement if antifungal combination therapy could be an effective treatment strategy in patients with mucormycosis.

Invasive fungal disease of the sinus and orbit: a comparison between mucormycosis and Aspergillus.

BACKGROUND/AIMS: Invasive fungal infections of the head and neck are rare life-threatening infections where prompt diagnosis and intervention is critical for survival. The aim of this study is to determine the clinical characteristics and outcomes of invasive fungal disease of the sinus and orbit, and to compare mucormycosis and Aspergillus infection. METHODS: A retrospective review was conducted from a single tertiary care eye and ear hospital over 20 years (1994-2014). Twenty-four patients with a confirmed pathological diagnosis of invasive fungal disease of the sinus and/or orbit were identified and their medical records were reviewed. The main outcome measures were type of fungus, location of disease, mortality and visual outcome. RESULTS: Patients with orbital involvement had a higher mortality and higher likelihood of mucormycosis infection compared with those with sinus-only disease (78.6% vs 20%, p=0.01; 86% vs 30%, p=0.01, respectively). Patients with mucormycosis had a higher mortality (71%) than patients with Aspergillus (29%); however, this was not statistically significant (p=0.16). All patients with orbital involvement and/or mucormycosis infections were immunosuppressed or had inadequately controlled diabetes, and had a cranial neuropathy or ocular motility dysfunction. All five post-transplant patients with orbital infections died, while the two transplant patients with sinus infections survived. CONCLUSIONS: Patients with orbital fungal infections are more likely to be infected with mucormycosis compared with Aspergillus and have a higher mortality compared with infections sparing the orbit. History of transplant portends a dismal prognosis in orbital infections. Invasive fungal disease should be considered in any immunocompromised patient presenting with a new cranial neuropathy or ocular motility abnormality.

In vitro and in vivo activities of posaconazole and amphotericin B in a murine invasive infection by Mucor circinelloides: poor efficacy of posaconazole.

The in vitro susceptibility of 17 strains of Mucor circinelloides to amphotericin B and posaconazole was ascertained by using broth microdilution and disk diffusion methods and by determining the minimal fungicidal concentration (MFC). We evaluated the efficacy of posaconazole at 40 mg/kg of body weight/day and amphotericin B at 0.8 mg/kg/day in a neutropenic murine model of disseminated infection by M. circinelloides by using 6 different strains tested previously in vitro. In general, most of the posaconazole MICs were within the range of susceptibility or intermediate susceptibility, while the small inhibition zone diameters (IZDs) were indicative of nonsusceptibility for all isolates tested. The MFCs were ≥ 3 dilutions higher than the corresponding MICs. In contrast, amphotericin B showed good activity against all of the strains tested regardless of the method used. The in vivo studies demonstrated that amphotericin B was effective in prolonging survival and reducing the fungal load. Posaconazole showed poor in vivo efficacy with no correlation with the MIC values. The results suggested that posaconazole should be used with caution in the treatment of infections caused by Mucor circinelloides or by strains of Mucor not identified to the species level.

The Deferasirox-AmBisome Therapy for Mucormycosis (DEFEAT Mucor) study: a randomized, double-blinded, placebo-controlled trial.

OBJECTIVES: Host iron availability is fundamental to mucormycosis pathogenesis. The combination of liposomal amphotericin B (LAmB) and deferasirox iron chelation therapy synergistically improved survival in diabetic mice with mucormycosis. To determine the safety of combination deferasirox plus LAmB therapy for mucormycosis, a multicentred, placebo-controlled, double-blinded clinical trial was conducted. METHODS: Twenty patients with proven or probable mucormycosis were randomized to receive treatment with LAmB plus deferasirox (20 mg/kg/day for 14 days) or LAmB plus placebo (NCT00419770, clinicaltrials.gov). The primary analyses were for safety and exploratory efficacy. RESULTS: Patients in the deferasirox arm (n=11) were more likely than those in the placebo arm (n=9) to have active malignancy, neutropenia and corticosteroid therapy, and were less likely to receive concurrent non-study antifungal therapy. Reported adverse events and serious adverse events were similar between the groups. However, death was more frequent in the deferasirox than in the placebo arm at 30 days (45% versus 11%, P=0.1) and 90 days (82% versus 22%, P=0.01). Global success (alive, clinically stable, radiographically improved) for the deferasirox arm versus the placebo arm at 30 and 90 days, respectively, was 18% (2/11) versus 67% (6/9) (P=0.06) and 18% (2/11) versus 56% (5/9) (P=0.2). CONCLUSIONS: Patients with mucormycosis treated with deferasirox had a higher mortality rate at 90 days. Population imbalances in this small Phase II study make generalizable conclusions difficult. Nevertheless, these data do not support a role for initial, adjunctive deferasirox therapy for mucormycosis.

Comparative study of the efficacy of liposomal amphotericin B and amphotericin B deoxycholate against six species of Zygomycetes in a murine lethal infection model.

The objective of this study was to investigate the efficacy of liposomal amphotericin B (L-AMB) at a clinical dose (3 mg/kg) against six species (5 genera) of Zygomycetes in a murine lethal infection model, and to compare findings with those for deoxycholate amphotericin B (D-AMB). The correlation between in-vitro activity and in-vivo efficacy of L-AMB was also investigated. Cyclophosphamide-treated mice were inoculated intravenously with conidial suspensions. Four hours or 1 day after inoculation, a single dose of L-AMB or D-AMB was administered intravenously. The number of mice that survived for 14 days was recorded. L-AMB at a dose of at least ≥1 mg/kg significantly prolonged the survival time of infected mice compared with the control group. The ED50 of L-AMB was nearly equivalent to that of D-AMB, except for the treatment initiated on day 1 in the Rhizopus oryzae model. At the maximum tolerated dose (MTD) of each agent, survival percentages with L-AMB (10 mg/kg) were equal to or higher than those with D-AMB (1 mg/kg). The ED50 of L-AMB decreased as the MIC against the infecting strain decreased. In conclusion, L-AMB was effective at a clinical dosage, and at the MTD the efficacy of L-AMB was equal or superior to that of D-AMB in a murine model of disseminated zygomycosis. The in-vivo activity of L-AMB was correlated with its in-vitro activity.

Comparative pharmacodynamics of amphotericin B lipid complex and liposomal amphotericin B in a murine model of pulmonary mucormycosis.

We compared the kinetics of amphotericin B (AMB) lung accumulation and fungal clearance by liposomal amphotericin B (L-AMB) and amphotericin B lipid complex (ABLC) in a neutropenic murine model of invasive pulmonary mucormycosis (IPM). Immunosuppressed BALB/c mice were inoculated with 1 x 10(6) Rhizopus oryzae spores and administered L-AMB or ABLC at daily intravenous doses of 1, 5, or 10 mg/kg of body weight for 5 days starting 12 h after infection. At a dose of 10 mg/kg/day, both L-AMB and ABLC were effective at reducing the R. oryzae lung fungal burden and achieved lung tissue concentrations exceeding the isolate mean fungicidal concentration (MFC) of 8 microg/ml by 72 h. When ABLC was dosed at 5 mg/kg/day, the ABLC-treated animals had significantly higher AMB lung concentrations than the L-AMB treated animals at 24 h (6.64 and 1.44 microg/g, respectively; P = 0.013) and 72 h (7.49 and 1.03 microg/g, respectively; P = 0.005), and these higher concentrations were associated with improved fungal clearance, as determined by quantitative real-time PCR (mean conidial equivalent of R. oryzae DNA per lung, 4.44 +/- 0.44 and 6.57 +/- 0.74 log(10), respectively; P < 0.001). Analysis of the AMB tissue concentration-response relationships revealed that the suppression of R. oryzae growth in the lung required tissue concentrations that approached the MFC for the infecting isolate (50% effective concentration, 8.19 microg/g [95% confidence interval, 2.81 to 18.1 microg/g]). The rates of survival were similar in the animals treated with L-AMB and ABLC at 10 mg/kg/day. These data suggest that higher initial doses may be required during L-AMB treatment than during ABLC treatment of experimental IPM.

Hyperbaric oxygen in the treatment of invasive fungal infections: a single-center experience.

BACKGROUND: Invasive fungal infections by Mucorales or Aspergillus spp. are lethal infections in immune compromised patients. For these infections a multimodal approach is required. One potential tool for treating these infections is hyperbaric oxygen. OBJECTIVES: To evaluate the clinical course and utility of hyperbaric oxygen in patients with invasive fungal infections by Mucorales or Aspergillus spp. METHODS: We conducted a retrospective chart review of 14 patients treated with HBO as part of their multimodal therapy over a 12 year period. RESULTS: Most patients had significant immune suppression due to either drug treatment or their underlying disorder. Thirteen of the 14 underwent surgery as part of the treatment and all were receiving antifungal therapy while treated with the hyperbaric oxygen. The number of HBO sessions ranged between 1 and 44. Seven of the patients survived the infection. No patient developed complications due to HBO therapy. CONCLUSIONS: HBO is a potentially significant adjunct in the treatment of invasive fungal infections. Evidence on its usefulness as a standard of care in these infections is still lacking. Since it will be difficult to generate conclusive data regarding the importance of HBO in these infections, the value of HBO in these patients should be considered on an individual basis.

Survival factors in rhino-orbital-cerebral mucormycosis.

Mucormycosis is a highly aggressive fungal infection affecting diabetic, immunocompromised, and, occasionally, healthy patients. This infection is associated with significant mortality. We have reviewed 208 cases in the literature since 1970, 139 of which were presented in sufficient detail to assess prognostic factors, and added data from six of our patients. The histories of these 145 patients were analyzed for the following variables: 1) underlying conditions associated with mucormycotic infections; 2) incidence of ocular and orbital signs and symptoms; 3) incidence of nonocular signs and symptoms; 4) interval from symptom onset to treatment; and 5) the pattern of sinus involvement seen on imaging studies and noted at the time of surgery. Factors related to a lower survival rate include: 1) delayed diagnosis and treatment; 2) hemiparesis or hemiplegia; 3) bilateral sinus involvement; 4) leukemia; 5) renal disease; and 6) treatment with deferoxamine. The association of facial necrosis with a poor prognosis fell just short of statistical significance, but appears clinically important. This is the first review that documents the heretofore intuitive claim that early diagnosis is necessary to cure this disease. Standard treatment with amphotericin B and aggressive surgery are reviewed and adjunctive therapeutic modalities are discussed, including local amphotericin B irrigation, hyperbaric oxygen, and optimizing the immunosuppressive regimen in transplant patients. Hyperbaric oxygen was found to have a favorable effect on prognosis. In addition, possible treatment options for patients with declining renal function are reviewed.