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. 2021 Jul 12;39(4):473–474. doi: 10.1016/j.ijmmb.2021.06.013

Rhizopus homothallicus: An emerging pathogen in era of COVID-19 associated mucormycosis

Harsimran Kaur 1,, Rimjhim Kanaujia 1, Shivaprakash M Rudramurthy 1
PMCID: PMC8275028  PMID: 34266698

India is facing a huge surge in COVID-19 associated mucormycosis (CAM) cases with a high mortality rate.1 We report here a very young patient of CAM by a rare pathogen, Rhizopus homothallicus.

A 21-year-old COVID-19 positive female with uncontrolled type 1 diabetes mellitus presented with five days history of progressive right-sided facial pain and swelling. Her fasting blood sugar levels were recorded at 365 ​mg/dl on admission. She had no history of steroid intake. Clinical examination revealed necrotic lesion in right nasal and palate area. Computed tomography paranasal sinuses (CT-PNS) showed soft-tissue density in right maxillary and anterior ethmoid sinuses. Diagnostic endoscopic biopsy from the necrotic lesions was performed and subjected to microbiological examination. The potassium hydroxide (KOH) mount from the biopsy revealed presence of broad, aseptate ribbon like hyphae suggesting a diagnosis of rhino-orbital mucormycosis. The patient underwent right-sided maxillectomy with orbital exenteration and was started on insulin for glycemic control and liposomal amphotericin B (3 ​mg/kg). The post-operative tissue also revealed aseptate hyphae and culture from both pre-operative and post-operative samples grew rapid-growing, floccose, cottony whitish colony turning brownish on Sabouraud dextrose agar (SDA) incubated at 25 ​°C and 37 ​°C. The lactophenol cotton blue (LCB) mount revealed broad, aseptate hyphae with numerous golden-brown spiny zygospores with suspensor cells (Fig. 1 ). The isolate was identified as R. homothallicus. The patient is currently improving.

Fig. 1.

Fig. 1

Lactophenol cotton blue (LCB) mount of R. homothallicus showing broad, aseptate hyphae with numerous golden-brown spiny zygospores with suspensor cells (x100). Inset (x400).

CAM in young patient demands prompt diagnosis and management. The emergence of R. homothallicus in causing CAM warrants epidemiological investigation.

Conflicts of interest

The authors declare that there are no conflicts of interest.

CRediT authorship contribution statement

Harsimran Kaur: Conceptualization, Data curation, Writing – review & editing. Rimjhim Kanaujia: Data curation, Writing – original draft, preparation. Shivaprakash M. Rudramurthy: Data curation, Writing – review & editing, Visualization, Investigation, Supervision.

Acknowledgement

We greatfully acknowledge Indian Council of Medical Research, New Delhi for extending financial support in this research work vide sanction letter no. MYCO/7/ 2020/ECD-1 dated 21-10-2020.

Reference

  • 1.Patel A., Agarwal R., Rudramurthy S.M., Shevkani M., Xess I., Sharma R., et al. Multicenter epidemiologic study of coronavirus disease-associated mucormycosis, India. Emerg Infect Dis. 2021 Jun;27(9) doi: 10.3201/eid2709.210934. 4. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Indian Journal of Medical Microbiology are provided here courtesy of Elsevier

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