Mucormycosis Amid COVID-19 Crisis: Pathogenesis, Diagnosis, and Novel Treatment Strategies to Combat the Spread

The havoc unleashed by COVID-19 pandemic has paved way for secondary ominous fungal infections like Mucormycosis. It is caused by a class of opportunistic pathogens from the order Mucorales. Fatality rates due to this contagious infection are extremely high. Numerous clinical manifestations result in damage to multiple organs subject to the patient's underlying condition. Lack of a proper detection method and reliable treatment has made the management of this infection troublesome. Several reports studying the behavior pattern of Mucorales inside the host by modulation of its defense mechanisms have helped in understanding the pathogenesis of this angio-invasive infection. Many recent advances in diagnosis and treatment of this fungal infection have not been much beneficial. Therefore, there is a need to foster more viable strategies. This article summarizes current and imminent approaches that could aid effective management of these secondary infections in these times of global pandemic. It is foreseen that the development of newer antifungal drugs, antimicrobial peptides, and nanotechnology-based approaches for drug delivery would help combat this infection and curb its spread.

Fungal endocarditis in transplant recipients: A systematic review

BACKGROUND

Invasive fungal infections remain a major cause of morbidity and mortality in transplant recipients. Moreover, Fungal Infective Endocarditis (FIE) is a rare infection that carries a higher mortality than bacterial IE in normal host, while in transplant recipients may be even higher. The purpose of this study was to systemically review all published cases of FIE in solid organ and allogeneic bone marrow transplant recipients, describe the epidemiology, microbiology, clinical characteristics, treatment and outcomes of these infections, and to identify risk factors for mortality by FIE.

METHODS

A systematic review of PubMed, Scopus and Cochrane Library (through 20 May 2020) for studies providing epidemiological, clinical, microbiological and treatment data and outcomes of FIE in transplant recipients was performed.

RESULTS

A total of 60 studies, containing data of 72 patients, were included. The most common transplants were those of the kidney and the liver, while the commonest causative pathogen was Aspergillus. Mitral valve was the commonest infected intracardiac site, followed by mural endocardium. Diagnosis was made with transthoracic echocardiography in 44.3%, while the diagnosis was made at autopsy in 37.3%. Embolic phenomena were the commonest clinical presentation, followed by fever, heart failure and endophthalmitis. Amphotericin B, voriconazole and caspofungin were the commonest antifungals used for treatment of FIE. Clinical cure was noted in 26.9%, while overall mortality was 78.6%. Amphotericin B or caspofungin use was negatively associated with overall mortality.

CONCLUSIONS

This systematic review thoroughly describes IE in transplant recipients and provides information on epidemiology, clinical presentation, treatment and outcomes.

Prevalence of Candida auris in Canadian acute care hospitals among at-risk patients, 2018

To identify the prevalence of C. auris in Canadian patients who are potentially at risk for colonization, we screened 488 patients who were either hospitalized abroad, had a carbapenemase-producing organism (CPO), or were in units with high antifungal use. Two patients were colonized with C. auris; both had received healthcare in India and had a CPO. Among 35 patients who had recently received healthcare in the Indian subcontinent and were CPO colonized or infected, the prevalence of C. auris was 5.7%.

Synergistic and antagonistic effects of immunomodulatory drugs on the action of antifungals against Candida glabrata and Saccharomyces cerevisiae

Candidemia and other forms of invasive fungal infections caused by Candida glabrata and to a lesser extent Saccharomyces cerevisiae are a serious health problem, especially if their steadily rising resistance to the limited range of antifungal drugs is taken into consideration. Various drug combinations are an attractive solution to the resistance problem, and some drug combinations are already common in the clinical environment due to the nature of diseases or therapies. We tested a few of the common antifungal-immunomodulatory drug combinations and evaluated their effect on selected strains of C. glabrata and S. cerevisiae. The combinations were performed using the checkerboard microdilution assay and interpreted using the Loewe additivity model and a model based on the Bliss independence criterion. A synergistic interaction was confirmed between calcineurin inhibitors (Fk506 and cyclosporine A) and antifungals (fluconazole, itraconazole, and amphotericin B). A new antagonistic interaction between mycophenolic acid (MPA) and azole antifungals was discovered in non-resistant strains. A possible mechanism that explains this is induction of the Cdr1 efflux pump by MPA in C. glabrata ATCC 2001. The Pdr1 regulatory cascade plays a role in overall resistance to fluconazole, but it is not essential for the antagonistic interaction. This was confirmed by the Cgpdr1Δ mutant still displaying the antagonistic interaction between the drugs, although at lower concentrations of fluconazole. This antagonism calls into question the use of simultaneous therapy with MPA and azoles in the clinical environment.

Necrotizing encephalitis caused by disseminated Aspergillus infection after orthotopic liver transplantation

Liver transplantation is the only available treatment for some patients with end-stage liver disease. Despite reduction in mortality rates due to advances related to surgical techniques, intensive medical management and immunosuppressive therapy, invasive fungal infections remain a serious complication in orthotopic liver transplantation. We report the case of an 18-year-old male diagnosed with autoimmune cirrhosis in 2009 who was assessed and listed for liver transplantation for massive variceal hemorrhage. One year after listing a successful orthotopic liver transplantation was performed. Uneventful early recovery was achieved; however, he developed pulmonary and neurological Aspergillus infection 23 and 40 days after surgery, respectively. Antibiotic therapy with voriconazole and amphotericin was started early, with no major response. Neuroimaging revealed multiple right frontal and right parietal lesions with perilesional edema; surgical management of the brain abscesses was performed. A biopsy with periodic acid-Schiff and Gomori stains revealed areas with mycotic microorganisms morphologically consistent with Aspergillus, later confirmed by culture. The patient developed necrotizing encephalitis secondary to aspergillosis and died. Necrotizing encephalitis as a clinical presentation of Aspergillus infection in an orthotopic liver transplant is not common, and even with adequate management, early diagnosis and prompt antifungal treatment, mortality rates remain high.