Hit or Miss: The Dilemma of Specimen Selection for Microbiological Diagnosis of Rhino-Orbital-Cerebral- COVID-Associated Mucormycosis (ROCM-CAM).

BACKGROUND

We diagnosed various cases of rhino-orbital-cerebral- COVID-associated Mucormycosis (ROCM-CAM) during India's second wave of COVID-19. This helped formulate novel suggestions for improving laboratory output, applicable anywhere in the world.

METHODS

To diagnose ROCM-CAM by microbiological methods, we used direct microscopy and conventional culture on various clinical samples within the shortest turn-around time.

DESIGN

Prospective single-center observational study.

PARTICIPANTS

Patients with ROCM-CAM.

RESULTS

Of 113 suspected cases of ROCM-CAM during May 2021, direct microscopy and culture could confirm the disease in 87.61% and 44.25% of patients, respectively. The highest pathogen isolation was seen from maxillary bone fragments, FESS-guided biopsy from pterygopalatine fossae, nasal turbinates and nasal mucosal biopsy. Direct microscopy could diagnose the disease in almost 40% of patients within 24 hours and 60% within two days. Conventional cultures yielded Rhizopus spp. (86%) as the commonest fungal pathogen followed by Mucor spp. (12%) within 7 days. Deep tissue biopsies are more useful for rapid diagnosis than superficial specimens. Routine fungal cultures can supplement case detection and help prognosticate survivors.

CONCLUSION

The management of ROCM is a surgical emergency. The diagnosis of the condition must therefore be prompt and precise. Despite ongoing antifungal therapy, nasal mucosal tissue, FESSguided, and intra-operative tissue biopsies showed the pathogen's highest diagnostic yield. The diagnostic index improved further when multiple (4-5) high-quality specimens were collected. Nasal swabs and crusts, among the most commonly requested specimens worldwide, were found to have an overall low diagnostic potential.