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.

Selection and evaluation of appropriate reference genes for RT-qPCR based expression analysis in Candida tropicalis following azole treatment.

Candida tropicalis arises as one of the predominant non-Candida albicans Candida (NCAC) species causing invasive candidiasis in Asian countries. A rise in reports of C. tropicalis with a parallel increase in fluconazole resistance has also been observed. The genes and underlying pathways associated with azole antifungal resistance in C. tropicalis is still not properly understood. The RT-qPCR is the most promising approach for expression analysis of target genes to understand the mechanisms of resistance. The reliability and reproducibility of this technique depend on the selection of suitable reference genes for the normalization in expression study. The present study investigated the expression stability levels of ten genes including ACT1, EF1, GAPDH, PGK1, RDN5.8, RDN18, RDN28, SDHA, TUB1, and UBC13 for their suitability in fluconazole treated/untreated C. tropicalis. The stability levels of these genes were examined by the ∆∆CT, ΔCT, Pfaffl methods and five independent software including hkgFinder, geNorm, NormFinder, BestKeeper, and RefFinder software. We report, the EF1 and ACT1 were the most stable reference genes for normalization and can be used for the gene expression analysis in C. tropicalis. To the best of our knowledge, our study is the first to select and validate the reference genes in C. tropicalis for RT-qPCR based expression analysis.

A randomised trial of vitamin D in acute-stage allergic bronchopulmonary aspergillosis complicating asthma.

Vitamin D has been demonstrated to have an immunomodulatory role in cystic fibrosis with allergic bronchopulmonary aspergillosis (ABPA). Herein, we evaluate supplemental vitamin D in acute-stage ABPA complicating asthma. Thirty subjects were randomised to receive either prednisolone (n = 15, control) or prednisolone and oral vitamin D (n = 15, intervention arm). Serum vitamin D levels were significantly higher in the intervention versus the control arm, following therapy. The mean decline in total IgE at 2 months (primary outcome) was 10% higher in the intervention arm than the control arm; however, this was not statistically significant (48.6% vs 38.1%, P = 0.27). The percentage decline in total IgE after 4 and 6 months of randomisation was also similar in the two arms. There was no difference in asthma exacerbations (0 vs 2, intervention vs control; P = 0.16). No ABPA exacerbation occurred in either arm. The other outcomes including the Th2 (IL-4, IL-6 and IL-10) and Th17 (IL-17) cytokine levels were similar in the two groups. None of the participants experienced hypervitaminosis D. There was no significant improvement in the clinical or immunological outcomes following vitamin D supplementation. A larger trial is required to ascertain the role of vitamin D in ABPA complicating asthma [Clinicaltrials.gov: NCT03133299].

Pharmacodynamics of Voriconazole against Wild-Type and Azole-Resistant Aspergillus flavus Isolates in a Nonneutropenic Murine Model of Disseminated Aspergillosis.

Invasive aspergillosis (IA) due to Aspergillus flavus is associated with high mortality. Although voriconazole (VRC) is widely recommended as the first-line treatment for IA, emergence of azole resistance in Aspergillus spp. is translating to treatment failure. We evaluated the efficacy of voriconazole in a nonneutropenic murine model of disseminated A. flavus infection using two voriconazole-resistant isolates (one harboring the Y319H substitution in the cyp51C gene) and two wild-type isolates without mutations. All isolates exhibited a dose-response relationship, and voriconazole treatment improved mouse survival in a dose-dependent manner. At 40 mg/kg of body weight, 100% efficacy was observed for 1 susceptible isolate and 1 resistant isolate (with mutation), whereas for another susceptible isolate and resistant isolate (without mutation), survival rates were 81% and 72%, respectively. The Hill equation with a variable slope fitted the relationship between the area under the concentration-time curve (AUC)/MIC ratio and 14-day survival well for each strain. An F test showed the 50% effective doses to be significantly different from each other (P = 0.0023). However, contrary to expectation, there was a significant difference in exposure-response relationships between strains, and it appeared that the susceptible strains required a relatively higher exposure than the resistant ones to result in the same treatment effect, the 50% effective pharmacokinetic/pharmacodynamic (PK/PD) index (EI50) required being negatively and log-linearly related to the MIC (P = 0.04). We conclude that the efficacy of voriconazole depended on drug exposure and the voriconazole MIC of the isolates, but lower exposures are required for strains with higher MICs. These findings may have profound significance in clinical practice with respect to dosing and drug choice.

Incidence, characteristics and outcome of ICU-acquired candidemia in India.

PURPOSE: A systematic epidemiological study on intensive care unit (ICU)-acquired candidemia across India. METHOD: A prospective, nationwide, multicentric, observational study was conducted at 27 Indian ICUs. Consecutive patients who acquired candidemia after ICU admission were enrolled during April 2011 through September 2012. Clinical and laboratory variables of these patients were recorded. The present study is an analysis of data specific for adult patients. RESULTS: Among 1,400 ICU-acquired candidemia cases (overall incidence of 6.51 cases/1,000 ICU admission), 65.2 % were adult. Though the study confirmed the already known risk factors for candidemia, the acquisition occurred early after admission to ICU (median 8 days; interquartile range 4-15 days), even infecting patients with lower APACHE II score at admission (median 17.0; mean ± SD 17.2 ± 5.9; interquartile range 14-20). The important finding of the study was the vast spectrum of agents (31 Candida species) causing candidemia and a high rate of isolation of Candida tropicalis (41.6 %). Azole and multidrug resistance were seen in 11.8 and 1.9 % of isolates. Public sector hospitals reported a significantly higher presence of the relatively resistant C. auris (8.2 vs. 3.9 %; p = 0.008) and C. rugosa (5.6 vs. 1.5 %; p = 0.001). The 30-day crude and attributable mortality rates of candidemia patients were 44.7 and 19.6 %, respectively. Logistic regression analysis revealed significant independent predictors of mortality including admission to public sector hospital, APACHE II score at admission, underlying renal failure, central venous catheterization and steroid therapy. CONCLUSION: The study highlighted a high burden of candidemia in Indian ICUs, early onset after ICU admission, higher risk despite less severe physiology score at admission and a vast spectrum of agents causing the disease with predominance of C. tropicalis.