Rapid and Low-Cost Culture-Based Method for Diagnosis of Mucormycosis Using a Mouse Model

Abstract

Prompt and targeted antifungal treatment has a positive impact on the clinical outcome of mucormycosis; however, current diagnostic tools used in histopathology laboratories often fail to provide rapid results. Rapid culture-based strategies for early diagnosis of Mucorales infections, which may influence treatment decisions, are urgently needed. Herein, we evaluated a microculture assay for the early diagnosis of mucormycosis in an immunocompetent murine model of disseminated infection, by comparing it with traditional diagnostic methods. The assay specificity was assessed using blood (n = 90) and tissue (n = 90) specimens obtained from mice infected with Rhizopus arrhizus using different inoculum sizes [1 × 10 4 , 1 × 10 5 , and 1 × 10 6 colony forming units (CFUs)/mouse] and blood (n = 15) and tissue specimens (n = 15) from uninfected mice. Surprisingly, 26 of 90 (28.9%) blood samples revealed positive results by microculture, whereas all blood samples were negative when assayed by conventional culture. The overall positive conventional culture rate for the mouse tissue (kidney) samples was 31.1% (28/90). The calculated sensitivity for kidney microculture was 98.8% [95% confidence interval (CI) 96.6-100], with an assay specificity of 100%. Hence, the microculture assay may be useful for rapid culturing and diagnosis of mucormycosis caused by R. arrhizus directly in blood and tissue samples. Hence, this method may allow for the timely administration of an appropriate treatment.

Evaluation of MucorGenius® mucorales PCR assay for the diagnosis of pulmonary mucormycosis

“…Conventional culture and histopathology-based screening are still the mainstay of the EORTC-MSG biological criteria for IFD (13), but these approaches may be insensitive and may delay the diagnosis. Besides, a promising microculture method has been recently reported to raise drastically the yield of mycological culture in a Rhizopus-infected murine model (14). While the critical interest of molecular techniques, combined with the detection of galactomannan or beta-glucan, has been extensively reported for the diagnosis of IA (15,16) and…”

“…Indeed, the sensitivity of BAL culture for IMD diagnosis has been reported to be as low as 30 to 50% (22,33,34). By contrast, a microculture capillary-based assay from both deep tissue and blood samples has been proposed as a promising tool in a murine model of mucormycosis (14). This new process was shown to increase from 31.1% (28/90) to 98.8 % (89/90) the sensitivity of conventional culture from mouse kidney samples after Rhizopus intravenous inoculation.…”

Mucormycosis-unusual cause of lower GI bleeding: A rare case report

“…The diagnosis is established histopathologically by the presence of characteristic broad, branching and non-septate hyphae in infected tissues, usually in connotation with angioinvasion, vascular thrombosis and infarction like in our case there was similar features of fungi without identifiable vascular invasion. Histologically it has been categorized into colonization, infiltrative and invasive as in our case its colonized type [6] .…”

“…Clinical progression is rapid and almost universally fatal if untreated [5] . It is diagnosed by histopathological examination or tissue culture [6] . It is treated by systemic antifungal drug and surgical debridement or resection.…”

New Insights on Mucormycosis and Its Association With the COVID-19 Pandemic

“…However, current diagnostic tools may fail to provide rapid results. Recently, there has been a trend for the use of rapid micro-culture assay strategies for early diagnosis of Mucorales infections caused by R. arrhizus directly in blood and tissue samples [ 127 ].…”