Jayachitra, J (2018) Isolation, characterisation and antifungal sensitivity pattern of fungi causing otomycosis in patients reporting in a tertiary care hospital. Masters thesis, Kilpauk Medical College, Chennai.
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Abstract
INTRODUCTION: Otomycosis refers to superficial, fungal infection of the external auditory canal. Aspergillus and Candida are the most common organisms causing otomycosis. AIMS AND OBJECTIVES: 1. To isolate, identify, speciate and characterise fungi isolated from patients with clinically suspected otomycosis. 2. To determine antifungal susceptibility pattern of the isolates. MATERIALS AND METHODS: This study was conducted in the Department of Microbiology, Kilpauk Medical College and Hospital, Chennai from January 2016 to December 2016. The fungi isolated from otomycosis were identified using standard identification methods. Virulence factors were determined by virulence tests. Aflatoxin production was tested by HPLC. Antifungal susceptibility was tested by microbroth dilution method for moulds and disc diffusion method for yeasts. Results were interpreted according to CLSI guidelines (M38-A2 & M44A). Rare isolates were subjected to PCR followed by Sanger sequencing. RESULT: In our study, majority of positive samples were in the age group 21-30 years (25.71%). Habitual cleaning of ear (70%) was the commonest predisposing factor. We isolated a total of 105 fungal isolates from 200 cases of clinically suspected otomycosis, among which Aspergillus niger 51 (49%) and Candida albicans 20 (19%) were the predominant species isolated. Rare isolates were Cladosporium cladosporoides (2), Aspergillus nidulans (1), Aureobasidium pullulans (1), Fonsaceae pedrosoi (1), Rhizomucor (1), Candida parapsilosis (2), Candida glabrata (1) and Candida krusei (1). Virulence factors like Biofilm in Candida species (29%), Urease and Hemolysin in Aspergillus species were produced. Higher production of Aflatoxins B1, G1 was seen with Aspergillus niger while Aspergillus flavus and Aspergillus terreus produced more amounts of Aflatoxins B2, G2. All the filamentous fungi were susceptible to antifungal drugs. Among Candida isolates, 2 Candida albicans and 1 Candida parapsilosis were resistant to Fluconazole and 1 Candida albicans was resistant to Itraconazole. 2 isolates were identified as Cladosporidium cladosporoides by PCR and Sanger sequencing. All the patients showed good response to treatment, with negative culture by 2 weeks. CONCLUSION: The present study shows that Otomycosis is a benign condition, frequently encountered in our region, which responds well to topical antifungals. Diagnosis of otomycosis at the earliest, confirmation with virulence tests and identification of antifungal susceptibility pattern is mandatory to effectively manage otomycosis without complications or recurrence.
| Item Type: | Thesis (Masters) |
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| Uncontrolled Keywords: | Otomycosis ; Aspergillus ; fungal virulence factors ; Aflatoxin ; Antifungal susceptibility testing ; Molecular diagnosis of fungi. |
| Subjects: | MEDICAL > Microbiology |
| Depositing User: | Subramani R |
| Date Deposited: | 12 Jul 2018 17:45 |
| Last Modified: | 12 Jul 2018 17:45 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/8716 |
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