P053 Invasive Mucormycosis (Zygomycosis) -Pre-Covid Era and Covid Era: a retrospective study at a tertiary care centre, chennai
Authors: K Malavika , Thayanidhi Premamalini , P Sathyamurthy , Kindo Anupma Jyoti 
Published: September 2022

Abstract

Poster session 1, September 21, 2022, 12:30 PM - 1:30 PM

Objectives

Methods
This is a retrospective, hospital-based descriptive study. This study included patients admitted during the pre-COVID and COVID era at a tertiary care center, Chennai. The cases were categorized into two: (1) possible mucormycosis cases which included direct microscopy [Potassium hydroxide (KOH) and histopathological examination] positives and (2) confirmed cases which included direct microscopy and culture positives. Direct microscopic examinations like KOH wet mount and histopathological examination (H and E stain and special stains) were performed. Samples were cultured on Sabourauds dextrose agar and identification was done by analyzing the microscopic morphology using lactophenol cotton blue mount. AFST was performed for culture positive isolates with amphotericin B, itraconazole, posaconazole, voriconazole and isavuconazole by microbroth dilution method according to CLSI M38-A2.

Results
During the Pre-COVID era, out of the 365 samples received in the laboratory, 35 were possible mucormycosis cases. Only 17 were confirmed cases, out of which 16 grew Rhizopus oryzae and 1 grew Apophysomyces elegans. During the COVID era, among 886 samples received in the laboratory, 143 were possible mucormycosis cases, and 31 were confirmed cases that grew Rhizopus oryzae (26), Rhizomucor pusillus (2), Mucor sp (2), and Basidiobolus ranarum (1). Though the risk factors were common during the pre-COVID and COVID era, additional risk factors like steroid therapy (19.2%), and COVID infection (28.7%) were seen during the COVID era. Though clinical presentations were common during both pre-COVID and COVID era, additional complications like epistaxis (0.57%), orbital cellulitis (32.7%), and loss of smell (8.04%) were seen during COVID era. The prevalence of complications was more during COVID era compared to pre-COVID era. Treatment received during the pre-COVID era was only amphotericin B, whereas during the COVID era majority of the patients received posaconazole (74.5%) followed by liposomal amphotericin B (25.5%). The antifungal susceptibility test showed the following mean minimum inhibitory concentration (MIC) values: amphotericin B (1.8 μg/ml), itraconazole (3.6 μg/ml), posaconazole (0.31 μg/ml), and voriconazole (1.61 μg/ml) during the pre-COVID era while the mean MIC values during the COVID era had the following variations: amphotericin B (0.97 μg/mL), itraconazole (13.6 μg/ml), Posaconazole (13.4 μg/ml), voriconazole (14.5 μg/ml), and isavuconazole (1.10 μg/ml).

Conclusion
High incidence of Mucormycosis during the COVID-19 era may be related to common risk factors of COVID and mucormycosis. Though most of the risk factors and clinical presentations were similar during the pre-COVID and COVID era, serious complications like loss of vision and the percentage of complications were more during COVID era which may be attributed to the increased invasiveness of Zygomycetes during COVID infection. The high mean MIC value of amphotericin B during pre-COVID era and higher mean MIC value of posaconazole during COVID era may be contributed to the higher usage of these antifungals. Usage of the antifungal agents is the main contributor toward the resistance. Newer azole like isavuconazole which had a low mean MIC in our study, can be considered as a good therapeutic option for the future management of resistant infections. Hence timely management of the patients with an appropriate antifungal agent by performing AFST will help in the reduction of resistance in the future.