Evaluation of Direct Examination, Culture, and Histopathology in the Diagnosis of Mucormycosis: Reiterating the Role of KOH Mount for Early Diagnosis

Abstract

Introduction Invasive fungal infections have always been a major cause of mortality and morbidity and are especially prevalent in the immunosuppressed groups of patients. Members of the Mucoracea family have an increasing incidence and prevalence. It has always been difficult to diagnose this condition due to various reasons. Materials and Methods This was an observational study carried out jointly by the Department of Microbiology and the Department of Pathology for a duration of one year. All patients who presented in various clinical departments with a high index of clinical suspicion for mucormycosis were included in this study. A total of 186 samples were received from suspected cases of mucormycosis and were all subjected to direct microscopy by potassium hydroxide (KOH), fungal culture, and histopathological examination. Results Mucormycosis was documented in 33 out of 186 cases on direct microscopy, whereas 21 were positive on fungal culture. Histopathological positivity was reduced with only 11 cases showing aseptate hyphae suggestive of mucormycosis. Conclusion As these organisms generally do not grow well on routine culture media and with the histopathological results also being not suggestive clearly of mucormycosis, direct microscopy thus becomes more important and essential in the rapid diagnosis of this deadly condition.

A Comparison Between Potassium Hydroxide (KOH) Microscopy and Culture for the Detection of Post-COVID-19 Rhino-Orbital-Cerebral Mucormycosis

“…In our study, KOH microscopy had a moderate agreement (k: 0.422) with culture; it had a high sensitivity (84.92%), specificity (61.56%), and very good NPV (87.23%) when compared with gold standard cultures. Similar findings have been reported by Mohanty et al (2021). The low PPV observed (56.90%) could be due to the low growth of Mucorales on culture [8].…”

“…However, the growth in cultures from the samples was not 100%. Walsh et al and Mohanty et al observed positivity of below 50% in cultures [8,9]. In our study, the positivity rate was only 34.2%.…”

A Fatal Case of Otomycosis due to Lichtheimia Spp in an Immunocompromised Patient with a Brief Review of Lichtheimia

“…The diagnosis was confirmed by SDA Culture. Our KOH and SDA Culture findings were concordant with study done by Mohanty A et al 2021 [57] . where it was found out that out of 186 samples 6 samples (3.22%) were only positive in Culture and an another study by Begari V et.al 2019 [58] .…”

Mucormycosis an added burden to Covid-19 Patients: An in-depth systematic review

“…Mucormycosis diagnosis requires specimen culture for the genus/species identification and antifungal susceptibility testing. A direct microscopy, particularly when combined with fluorescent brighteners and dilacerating agents like KOH, can be utilised to provide quick tentative diagnosis of mucormycosis [106] . Under microscopic examination, mucorales have aseptate or semi-septate, uneven, tape-like hyphae, just as histological specimens’ even artificial septa can form as result of hyphal folding or development of one hyphae across another, just as they might in histological studies.…”