Case Series
Year : 2025 Month : January Volume : 14 Issue : 1 Page : MS01 - MS05 Full Version

A Case Series on Rhizopus homothallicus: An Emerging Zygomycete causing Mucormycosis
K Kavitha, S Meenakshi, B Shanthi
1. Associate Professor, Department of Microbiology, Government Karur Medical College, Karur, Tamil Nadu, India. 2. Professor, Department of Microbiology, Government Coimbatore Medical College, Coimbatore, Tamil Nadu, India. 3. Associate Professor, Department of Microbiology, Madras Medical College, Chennai, Tamil Nadu, India.
 
Correspondence Address :
K Kavitha, S Meenakshi, B Shanthi,
K Kavitha,
32 A, Ther Pillaiyar Koil Street, K.K Nagar, Villupuram-605602, Tamil Nadu, India.
E-mail: sahanathirumurugan@gmail.com
 
ABSTRACT
: Mucormycosis is an acute opportunistic infection caused by various fungi belonging to the family Mucorales. The most common species causing this infection in humans are Rhizopus (R) species (spp.,) with R. oryzae and R. microsporus being the most prevalent. The authors here report a case series of infections caused by a very rare emerging zygomycete, Rhizopus homothallicus, in a tertiary care Institution in Southern India. The first case involved a 26-year-old male who developed cutaneous mucormycosis following trauma and surgery, with no underlying co-morbidities. The second case was a 40-year-old male, a diabetic, who had recovered from Coronavirus Disease 2019 (COVID-19) and subsequently developed COVID-19-associated rhino-orbital mucormycosis. The third case was a 36-year-old male with a known history of insulin-dependent diabetes mellitus who developed pulmonary mucormycosis. In all three cases, the authors isolated a very rare zygomycete that was identified as Rhizopus homothallicus. The first patient was successfully discharged, while the second and third patients succumbed to the infection on days 12 and 8, respectively. There has been an increased incidence of mucormycosis in all forms post-COVID-19, and fungi that were previously considered rare, such as R. homothallicus, are now being encountered more frequently. Microbiologists and clinicians must maintain vigilance for these cases to ensure appropriate and prompt diagnosis and treatment, as current evidence suggests that the mortality rate associated with R. homothallicus is lower compared to other Mucorales when diagnosed and treated early. The present case series was aimed to highlight the importance of identifying fungi to the species level in all situations and to emphasise that, with a larger population living with immunosuppression and the emergence of new pandemics like COVID-19 compared to previous years, there is a heightened risk of infections from lesser-known pathogenic fungi such as R. homothallicus.
Keywords : Cutaneous mucormycosis, Emerging fungi, Pulmonary mucormycosis, Rhino-orbital mucormycosis
DOI and Others : DOI: 10.7860/NJLM/2025/69715.2891 Date of Submission: Jan 19, 2024 Date of Peer Review: Feb 14, 2024 Date of Acceptance: Sep 11, 2024 Date of Publishing: Jan 01, 2025 AUTHOR DECLARATION: • Financial or Other Competing Interests: None • Was informed consent obtained from the subjects involved in the study? Yes • For any images presented appropriate consent has been obtained from the subjects. Yes PLAGIARISM CHECKING METHODS: • Plagiarism X-checker: Jan 22, 2024 • Manual Googling: Sep 04, 2024 • iThenticate Software: Sep 10, 2024 (15%) ETYMOLOGY: Author Origin EMENDATIONS: 6
 
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