Invasive Fungal Infections Associated with COVID-19.

The COVID-19 pandemic caused >6 million deaths worldwide, often from respiratory failure. Complications frequently occurred in hospitalized patients, particularly in the intensive care unit. Among these, fungal infections were a cause of high morbidity and mortality. Invasive aspergillosis, candidiasis and mucormycosis were the most serious of these infections. Risk factors included alterations in immune defense mechanisms by COVID-19 itself, as well as immunosuppression due to various therapies utilized in severely ill patients. Diagnosis was often challenging due to lack of sensitivity of current testing. Outcomes were generally poor, due to significant co-morbidities and delayed diagnosis, with mortality rates >50% in some studies. High index of clinical suspicion is needed to facilitate early diagnosis and initiation of appropriate antifungal therapy.

Infectious complications after second allogeneic hematopoietic cell transplant in adult patients with hematological malignancies.

We conducted a retrospective review of the infectious complications and outcomes over a 2-year follow-up period of adult patients who received a second allogeneic hematopoietic cell transplant (2nd allo-HCT) during a five-year period at two cancer centers in Michigan. Sixty patients, of whom 44 (73%) had acute leukemia or myelodysplastic syndrome, were studied. The majority (n = 37,62%) received a 2nd allo-HCT because of relapsed leukemia. Infection episodes after the 2nd allo-HCT totaled 112. Bacteria were identified in 76 episodes, the majority of which occurred pre-engraftment. The most common infecting organisms were Enterococcus species and Clostridioides difficile. Viral infections, predominantly cytomegalovirus, accounted for 59 infection episodes and occurred mostly in pre-engraftment and early post-engraftment periods. There were 16 proven/probable fungal infections, of which 9 were invasive aspergillosis or candidiasis. Mortality was 45% (n = 27) at one year and 65% (n = 39) at 2 years after transplant, and 16 deaths (41%) were due to infection. Of those 16 infection deaths, 8 were bacterial, 4 fungal, 2 both bacterial and fungal, and 2 viral. Failure to engraft neutrophils or platelets was significantly associated with decreased survival, p < 0.0001 and p < 0.001, respectively. Infections are common after a 2nd allo-HCT and are associated with a high mortality rate.

Evaluation of Susceptibility and Innate Immune Response in C57BL/6 and BALB/c Mice During Candida albicans Endophthalmitis.

Purpose: Candida remains the leading cause of fungal endophthalmitis. However, the pathobiology and innate immune responses in this disease are not well characterized. Here, we developed two murine models of candida endophthalmitis and evaluated their disease susceptibility and differential immune response. Methods: Endophthalmitis was induced in C57BL/6 (B6) and BALB/c mice by intravitreal injection of Candida albicans (CA). Disease progression was monitored by slit-lamp examination and clinical scoring, followed by retinal function assessment using electroretinography (ERG). Enucleated eyes were used to estimate fungal burden and retinal tissue damage by hematoxylin and eosin and TUNEL staining. The level of inflammatory mediators were determined by quantitative Polymerase Chain Reaction (qPCR) and enzyme-linked immunosorbent assay, whereas neutrophil infiltration was assessed by flow cytometry and immunostaining. Results: Intravitreal injection of CA at 6500 colony-forming units resulted in sustained (non-resolving) ocular inflammation in both B6 and BALB/c mice as evidenced by increased levels of inflammatory cytokines (tumor necrosis factor-α, interleukin-1ß, and interleukin-6) and chemokine (CXCL2/MIP-2). In both mouse strains, fungal burden peaked at 24 to 48 hours post-infection (hpi) and decreased by 72 to 96 hpi. CA-infected eyes exhibited increased polymorphonuclear neutrophils (PMN) infiltration and retinal tissue damage. Overall retinal function declined rapidly, with a significant reduction in ERG response at 12 hpi and near-total loss by 24 hpi. Differential analyses revealed increased pathology in BALB/c versus B6 mice. Conclusions: C. albicans was able to cause endophthalmitis in mice. Although BALB/c mice were found to be more susceptible to CA endophthalmitis, both BALB/c and B6 models could be used to study fungal endophthalmitis and test therapeutic modalities.

Utilization of COVID-19 Treatments and Clinical Outcomes among Patients with Cancer: A COVID-19 and Cancer Consortium (CCC19) Cohort Study.

Among 2,186 U.S. adults with invasive cancer and laboratory-confirmed SARS-CoV-2 infection, we examined the association of COVID-19 treatments with 30-day all-cause mortality and factors associated with treatment. Logistic regression with multiple adjustments (e.g., comorbidities, cancer status, baseline COVID-19 severity) was performed. Hydroxychloroquine with any other drug was associated with increased mortality versus treatment with any COVID-19 treatment other than hydroxychloroquine or untreated controls; this association was not present with hydroxychloroquine alone. Remdesivir had numerically reduced mortality versus untreated controls that did not reach statistical significance. Baseline COVID-19 severity was strongly associated with receipt of any treatment. Black patients were approximately half as likely to receive remdesivir as white patients. Although observational studies can be limited by potential unmeasured confounding, our findings add to the emerging understanding of patterns of care for patients with cancer and COVID-19 and support evaluation of emerging treatments through inclusive prospective controlled trials. SIGNIFICANCE: Evaluating the potential role of COVID-19 treatments in patients with cancer in a large observational study, there was no statistically significant 30-day all-cause mortality benefit with hydroxychloroquine or high-dose corticosteroids alone or in combination; remdesivir showed potential benefit. Treatment receipt reflects clinical decision-making and suggests disparities in medication access.This article is highlighted in the In This Issue feature, p. 1426.

Phaeohyphomycosis.

Phaeohyphomycosis refers to infections due to a large group of heterogenous organisms called "dematiaceous" or "melanized" fungi. These fungi are distinguished by the predominance of melanin in their cell walls, which likely acts as a virulence factor. Virtually, everyone is exposed to dematiaceous fungi through inhalation, as they are ubiquitous in the environment, although the development of infection is extremely uncommon. Invasive disease is rare but remains important due to the ability to cause serious disease in immunocompetent and immunocompromised hosts, unlike other fungal infections such as aspergillosis. A large variety of invasive manifestations can be caused by these organisms, including deep local infections, pulmonary infection, cerebral infection, and disseminated disease, which is associated with high mortality. While advances in molecular techniques are promising, they have still not replaced histology and culture as the primary diagnostic tools. Therapy is not standardized and is based primarily on clinical experience from descriptive case reports.

Pathobiology of Aspergillus Fumigatus Endophthalmitis in Immunocompetent and Immunocompromised Mice.

Despite Aspergillus being the leading cause of exogenous fungal endophthalmitis following traumatic injury to the eye, its pathogenesis is not fully understood. In the current study, we developed a murine model of Aspergillus fumigatus (AF) endophthalmitis and investigated the disease pathobiology. Endophthalmitis was induced by intravitreal injection of Aspergillus spores in immunocompetent and immunocompromised (neutropenic) C57BL/6 mice, and disease severity was assessed by eye exam, fungal burden estimation, and histological examination. Our data showed that AF infection caused a time-dependent increase in corneal haze, opacity, and hypopyon beginning at two days post-infection (DPI). The fungal burden in infected eyes of immunocompetent mice peaked at 2 DPI and declined over 9 DPI. AF-infected neuroretina exhibited induction of innate immune response via upregulation of Toll-like receptors (TLRs) and inflammatory mediators (TNFα, IL-1ß, and IL6), and increased polymorphonuclear neutrophil (PMN) infiltration. Histological analysis revealed heavy cellular infiltrates in the vitreous cavity as well as disruption of normal retinal architecture and increased retinal cell death. Neutropenic mice exhibited severe disease pathology with the prolonged fungal burden and increased inflammatory mediators. Our study described the first immunocompetent murine model of exogenous AF endophthalmitis and demonstrated an important role of neutrophils in innate defense against fungal endophthalmitis.

Infectious Complications After Umbilical Cord Blood Transplantation for Hematological Malignancy.

BACKGROUND: Umbilical cord blood transplant (UCBT) is used for patients who do not have a matched donor, but engraftment often takes longer than with a standard allogeneic transplant, likely increasing the risk for infection. We characterized specific infections and outcomes in adults undergoing UCBT at our 2 centers. METHODS: All adults who underwent UCBT between January 1, 2006 and December 31, 2015 were included. Infectious episodes from 6 months before to 2 years after UCBT were reviewed. RESULTS: Fifty-seven patients underwent UCBT; 47 had neutrophil engraftment. A total of 179 infectious episodes occurred in 55 patients, 73 (41%) within 30 days post-UCBT. Viruses caused 85 (47%) infections. Cytomegalovirus caused 32 infectious episodes and was most common from day 30 to 100. Human herpesvirus 6 occurred in 28 episodes, was most common within 30 days, and caused 1 death. Bacteria were responsible for 82 (46%) infections, most commonly bacteremias due to Staphylococcus spp, Enterococcus spp, and Enterobacteriaceae. Of 11 invasive fungal infections, 9 were aspergillosis, 4 of which were fatal. Overall mortality was 56% in the first year. Thirteen deaths were from infection; 11 occurred in the first 100 days and 7 in the first 30 days post-UCBT. Of 10 patients who never engrafted, 9 died, 6 from infection, within 100 days post-UCBT. CONCLUSIONS: Infectious complications were common after UCBT, especially in the first 30 days. Deaths from viral infections were fewer than expected. Delayed engraftment and nonengraftment continue to convey increased risk for fatal bacterial and fungal infections post-UCBT.

How Clean Is the Linen at My Hospital? The Mucorales on Unclean Linen Discovery Study of Large United States Transplant and Cancer Centers.

Mucormycosis outbreaks have been linked to contaminated linen. We performed fungal cultures on freshly-laundered linens at 15 transplant and cancer hospitals. At 33% of hospitals, the linens were visibly unclean. At 20%, Mucorales were recovered from >10% of linens. Studies are needed to understand the clinical significance of our findings.

Isavuconazole for Treatment of Experimental Fungal Endophthalmitis Caused by Aspergillus fumigatus.

Fungal endophthalmitis remains a significant cause of vision impairment and blindness. Moreover, the prognosis is poor, in part due to delay in diagnosis and to limited availability of effective antifungal agents with good ocular penetration. Thus, it is imperative to evaluate the therapeutic efficacy in fungal endophthalmitis of newer antifungal agents. In this study, we assessed the efficacy of isavuconazole in treating Aspergillus fumigatus endophthalmitis in an exogenous mouse model of the disease. Briefly, endophthalmitis was induced by intravitreal (IVT) injection of A. fumigatus spores into immunocompetent C57BL/6 (B6) mouse eyes. Mice were randomized into five groups that received isavuconazole via (i) oral gavage, (ii) IVT injections, (iii) intravenous injection, (iv) IVT injection followed by oral gavage, and (v) IVT injection followed by intravenous injection. Our data showed that isavuconazole treatment via all routes reduced fungal burden in A. fumigatus-infected eyes. This coincided with the preservation of retinal structural integrity (histology analysis) and retinal function (electroretinography [ERG] analysis), resulting in significantly improved disease outcome. Furthermore, isavuconazole treatment reduced the levels of inflammatory cytokines (tumor necrosis factor α [TNF-α], interleukin 1ß [IL-1ß], and IL-6) and cellular infiltration in the eyes. Notably, oral administration of isavuconazole was as effective in ameliorating endophthalmitis as intravitreal injection of the drug. Collectively, our study demonstrates that isavuconazole is effective in treating A. fumigatus endophthalmitis in mice, indicating its potential use in human ocular infections.

A Mycoses Study Group International Prospective Study of Phaeohyphomycosis: An Analysis of 99 Proven/Probable Cases.

BACKGROUND: Phaeohyphomycosis is infection caused by dematiaceous, or darkly pigmented, fungi. The spectrum of disease is broad, and optimal therapy remains poorly defined. The Mycoses Study Group established an international case registry of patients with proven/probable phaeohyphomycosis with the goal of improving the recognition and management of these infections. METHODS: Patients from 18 sites in 3 countries were enrolled from 2009-2015. Cases were categorized as local superficial, local deep (pulmonary, sinus, osteoarticular infections), and disseminated infections. End points were clinical response (partial and complete) and all-cause mortality at 30 days and end of follow-up. RESULTS: Of 99 patients, 32 had local superficial infection, 41 had local deep infection, and 26 had disseminated infection. The most common risk factors were corticosteroids, solid organ transplantation, malignancy, and diabetes. Cultures were positive in 98% of cases. All-cause mortality was 16% at 30 days and 33% at end of follow-up, and 18 of 26 (69%) with dissemination died. Itraconazole was most commonly used for local infections, and voriconazole was used for more severe infections, often in combination with terbinafine or amphotericin B. CONCLUSIONS: Phaeohyphomycosis is an increasingly recognized infection. Culture remains the most frequently used diagnostic method. Triazoles are currently the drugs of choice, often combined with other agents. Further studies are needed to develop optimal therapies for disseminated infections.

Dematiaceous Molds.

Dematiaceous fungi are the cause of phaeohyphomycosis, a term that encompasses many clinical syndromes, from local infections due to trauma to widely disseminated infection in immunocompromised patients. These fungi are unique owing to the presence of melanin in their cell walls, which imparts the characteristic dark color to their spores and hyphae. Melanin may also be a virulence factor. Local infection may be cured with excision alone, whereas systemic disease is often refractory to therapy. Azoles have the most consistent in vitro activity. Further studies are needed to better understand the pathogenesis and treatment of these uncommon infections.

Clostridium Difficile Colonization in Hematopoietic Stem Cell Transplant Recipients: A Prospective Study of the Epidemiology and Outcomes Involving Toxigenic and Nontoxigenic Strains.

Clostridium difficile is a leading cause of infectious diarrhea in hematopoietic stem cell transplant (HSCT) recipients. Asymptomatic colonization of the gastrointestinal tract occurs before development of C. difficile infection (CDI). This prospective study examines the rates, risk factors, and outcomes of colonization with toxigenic and nontoxigenic strains of C. difficile in HSCT patients. This 18-month study was conducted in the HSCT unit at the Karmanos Cancer Center and Wayne State University in Detroit. Stool samples from the patients who consented for the study were taken at admission and weekly until discharge. Anaerobic culture for C. difficile and identification of toxigenic strains by PCR were performed on the stool samples. Demographic information and clinical and laboratory data were collected. Of the 150 patients included in the study, 29% were colonized with C. difficile at admission; 12% with a toxigenic strain and 17% with a nontoxigenic strain. Over a 90-day follow-up, 12 of 44 (26%) patients colonized with any C. difficile strain at admission developed CDI compared with 13 of 106 (12%) of patients not colonized (odds ratio [OR], 2.70; 95% confidence interval [95% CI], 1.11 to 6.48; P = .025). Eleven of 18 (61%) patients colonized with the toxigenic strain and 1 of 26 (4%) of those colonized with nontoxigenic strain developed CDI (OR, 39.30; 95% CI, 4.30 to 359.0; P < .001) at a median of 12 days. On univariate and multivariate analyses, none of the traditional factors associated with high risk for C. difficile colonization or CDI were found to be significant. Recurrent CDI occurred in 28% of cases. Asymptomatic colonization with C. difficile at admission was high in our HSCT population. Colonization with toxigenic C. difficile was predictive of CDI, whereas colonization with a nontoxigenic C. difficile appeared protective. These findings may have implications for infection control strategies and for novel approaches for the prevention and preemptive treatment of CDI in the HSCT patient population.

Phaeohyphomycosis in Transplant Patients.

Phaeohyphomycosis is caused by a large, heterogenous group of darkly pigmented fungi. The presence of melanin in their cell walls is characteristic, and is likely an important virulence factor. These infections are being increasingly seen in a variety of clinical syndromes in both immunocompromised and normal individuals. Transplant patients are especially at risk due their prolonged immunosuppression. There are no specific diagnostic tests for these fungi, though the Fontana-Masson stain is relatively specific in tissue. They are generally seen in a worldwide distribution, though a few species are only found in specific geographic regions. Management of these infections is not standardized due to lack of clinical trials, though recommendations are available based on clinical experience from case reports and series and animal models. Superficial infections may be treated without systemic therapy. Central nervous system infections are unique in that they often affect otherwise normal individuals, and are difficult to treat. Disseminated infections carry a high mortality despite aggressive therapy, usually with multiple antifungal drugs. Considerable work is needed to determine optimal diagnostic and treatment strategies for these infections.

MSG-01: A randomized, double-blind, placebo-controlled trial of caspofungin prophylaxis followed by preemptive therapy for invasive candidiasis in high-risk adults in the critical care setting.

BACKGROUND: Invasive candidiasis is the third most common bloodstream infection in the intensive care unit (ICU) and is associated with morbidity and mortality. Prophylaxis and preemptive therapy are attractive strategies for this setting. METHODS: We conducted a multicenter, randomized, double-blind, placebo-controlled trial of caspofungin as antifungal prophylaxis in 222 adults who were in the ICU for at least 3 days, were ventilated, received antibiotics, had a central line, and had 1 additional risk factor (parenteral nutrition, dialysis, surgery, pancreatitis, systemic steroids, or other immunosuppressants). Subjects' (1,3)-ß-d-glucan levels were monitored twice weekly. The primary endpoint was the incidence of proven or probable invasive candidiasis by EORTC/MSG criteria in patients who did not have disease at baseline. Patients who had invasive candidiasis were allowed to break the blind and receive preemptive therapy with caspofungin. The preemptive approach analysis included patients all patients who received study drug, including those positive at baseline. RESULTS: The incidence of proven/probable invasive candidiasis in the placebo and caspofungin arms was 16.7% (14/84) and 9.8% (10/102), respectively, for prophylaxis (P = .14), and 30.4% (31/102) and 18.8% (22/117), respectively, for the preemptive approach (P = .04); however, this analysis included patients with baseline disease. There were no significant differences in the secondary endpoints of mortality, antifungal use, or length of stay. There were no safety differences. CONCLUSIONS: Caspofungin was safe and tended to reduce the incidence of invasive candidiasis when used for prophylaxis, but the difference was not statistically significant. A preemptive therapy approach deserves further study. CLINICAL TRIALS REGISTRATION: NCT00520234.

In vitro interaction of caspofungin and immunosuppressives against agents of mucormycosis.

OBJECTIVES: Mucormycosis is a rare but refractory mycosis with high mortality. Few therapeutic options are available and novel strategies are needed. Calcineurin inhibitors are known to have antifungal activity, including synergy with various antifungals. We examined the interaction of caspofungin with calcineurin inhibitors and sirolimus against Glomeromycetes. METHODS: Twenty-six strains of Glomeromycetes representing seven species (Rhizopus arrhizus, Rhizopus microsporus, Mucor sp., Rhizomucor pusillus, Cunninghamella berthollettiae, Mycocladus corymbifera and Apophysomyces elegans) were studied. Antifungal susceptibility testing was performed according to CLSI M38-A2, modified for chequerboard dilution testing using the minimum effective concentration (MEC) endpoint for caspofungin and calcineurin inhibitors/sirolimus. Synergy was defined as a fractional inhibitory concentration index ≤0.5, indifference >0.5 to ≤4.0 and antagonism >4.0. RESULTS: Caspofungin had no intrinsic activity against Glomeromycetes (MEC >8 mg/L). The combination of caspofungin with calcineurin inhibitors and sirolimus showed synergy in seven isolates. In the presence of calcineurin inhibitors and sirolimus, the MEC of caspofungin was significantly lowered (>4-fold) in 24 and 7 isolates, respectively. All species showed lower MECs of caspofungin with calcineurin inhibitors and only R. arrhizus, Mucor sp. and R. pusillus showed lower MECs with sirolimus. No antagonism was observed. CONCLUSIONS: Calcineurin inhibitors and sirolimus significantly lowered MECs of caspofungin for Glomeromycetes, with occasional synergy observed. The clinical significance of this should be further investigated.

Cladophialophora bantiana brain abscess in an immunocompetent patient.

Cladophialophora bantiana is a dematiaceous mold with a predilection for causing central nervous system infection, particularly in normal hosts. A case involving a 79-year-old immunocompetent woman who presented with left-sided weakness and a ring-enhancing brain lesion is reported. She underwent surgical excision, which revealed a brain abscess due to C bantiana. The patient was treated with liposomal amphotericin B for several weeks, then switched to voriconazole and flucytosine, but eventually succumbed to the infection. Therapy is not standardized for this rare mycosis, and mortality remains high, even in immunocompetent patients. Additional studies to understand the pathogenesis of this infection and to improve outcomes are needed.