Correlation of fungal cultures from non-sterile sites and Galactomannan assay with the diagnosis of aspergillosis and mucormycosis based on sterile culture results and histopathologic findings

Peritoneal dialysis-associated peritonitis from pauci-septated mold: Life-threatening but curable

Two cases of PD-associated peritonitis due to Cunninghamella (C. bertholletiae and C. guizhouensis) were reported here with favorable outcomes, albeit presenting with septicemia. Both patients presented with classic features of bacterial peritonitis, cloudy effluent with a neutrophil predominance, followed by fever and septicemia/septic shock. The pathogen species were confirmed and verified by molecular phylogeny using universal and specific fungal primers. All isolations were susceptible/intermediately susceptible to amphotericin B but resistant to other antifungal agents, including triazoles, caspofungin, and terbinafine. Both cases were successfully treated with timely PD catheter removal and antifungal medications for 2-4 weeks.

Pulmonary mucormycosis in the aftermath of critical COVID-19 in an immunocompromised patient: Mind the diagnostic gap

Mucormycosis has recently been recognized as a severe complication of COVID-19 with high fatality rates. We report a fatal case of COVID-19 associated mucormycosis (CAM) in a non-diabetic immunocompromised patient, who was first misdiagnosed and treated for COVID-19 associated aspergillosis (CAPA). The risk factors and initial clinical presentation of CAPA and CAM are similar, but CAM has a more aggressive course and CAPA and CAM are treated differently. Dedicated diagnostic workup is essential to ensure early treatment of CAM with surgical debridement and targeted antifungal therapy.

A comparison of histomorphologic diagnosis with culture- and immunohistochemistry-based diagnosis of invasive aspergillosis and mucormycosis

Background: Due to the low sensitivity of mould culture, clinicians usually depend on the histomorphologic diagnosis of invasive mould infection for empirical antifungal therapy. However, definite diagnosis is not always possible based on the mould morphology. We thus compared the histomorphologic diagnosis with immunohistochemistry (IHC)- and culture-based diagnosis.Methods: All adult patients who underwent tissue biopsy and in whom the histomorphologic diagnosis revealed invasive mould infection were enrolled at a tertiary hospital, Seoul, South Korea, between 1992 and 2014 (retrospectively) and 2015 and 2019 (prospectively). Their histomorphologic diagnoses were classified as two categories: (1) acute-angled branching, septate hyphae with parallel walls and a uniform width ('morphologic aspergillosis') and (2) right-angled branching pauciseptate, broader and ribbon-like hyphae with nonparallel walls ('morphologic mucormycosis').Results: A total of 113 patients were finally analysed and their histomorphologic diagnoses were classified as follows: 51 (45%) with morphologic aspergillosis, 62 (55%) with morphologic mucormycosis. Of the 51 patients with morphologic aspergillosis, 46 (90%) received the same diagnosis based on culture and/or IHC, and the remaining five (10%) gave positive IHC result for mucormycosis. Of the 62 patients with morphologic mucormycosis, 60 (97%) had the same diagnosis based on culture and/or IHC, and the remaining two (3%) yielded a positive aspergillus culture or a positive IHC result for aspergillosis, respectively.Conclusions: The majority of histomorphologic diagnoses appear to be consistent with definitive diagnoses based on sterile culture and IHC tests. However, about 10% of 'morphologic aspergillosis' diagnoses were mucormycosis cases.