I MYCOSES 38, 297-300 (1995) ACCEPTED: FEBRUARY 9, 1995

CASE REPORT

Chronic bilateral suppurative otitis media caused by Aspergillus teweus

C hronische bilaterale suppurative Otitis media durch Aspergillus terreus

Sunita Tiwari', S. M. Singh' and Sandeep Jain2

Key words. Aspergillus tmeus, otitis media, antimycotic chemotherapy, ketoconazole. Schltisselworter. Aspergillus terreus, Otitis media, antimykotische Chemotherapie, Ketoconazol.

Summary. A case of bilateral suppurative otitis media is described in a patient with the presenting symptoms of otorrhoea, itching, mild deafness, heaviness in the ear and otalgia. The patient had perforation in the tympanic membrane. Histological sections revealed aggregated fungal masses of Aspergillus terreus. The infection responded well to topical ketoconazole therapy. Incidentally, this is the second case from India of chronic suppurative otitis media caused by fungi.

Zusammenfassung. Ein Fall von beidseitiger, eiternder Otitis media mit den Symptomen Otor- rhoe, Juckreiz, leichter Taubheit, Druckgefiihl und Schmerzen im Ohr wird beschrieben. Der Patient hatte eine Perforation des Trommelfells. Histologi- sche Schnitte zeigten aggregierte Pilzmassen von Aspergillus terreus. Die Infektion sprach gut auf eine topische Behandlung mit Ketoconazol an. Dies ist in Indien der zweite berichtete Fall von pilzbeding- ter chronischer, eiternder Otitis media.

Introduction

Aspergillus terreus is a common mould with a wide- spread distribution occurring on a variety of sub- strates. It is a common soil organism and is found frequently on all kinds of vegetable material.

'Medical Microbiology Laboratory, Department of Biological Science, Rani Durgavati University, Jabalpur, and 'ENT Clinic, Prasann ENT Hospital Marhatal, Jabalpur, India.

Correspondence: Dr S. M. Singh, Medical Microbiology Laboratory, Department of Biological Sciences, Rani Durgavati University, Jabalpur - 482 001, India.

A. terreus has been isolated from the soil of the paddy field in Bengal [ 11 and from the interior of cotton seed in Madras [2]. It has also been reported to cause otomycosis in man [3]. A. tmeus has been isolated from moist leather, rotting rep- tilian eggs, decaying vegetables, soil [4] and also from the atmosphere in Kanpur [ 5 ] .

Cases of middle ear infection by fungi are rare. Recently a case of suppurative otitis media caused by Paecilomyces variotii was reported [6]. The pur- pose of this paper is to present a case with the clinical picture of bilateral chronic suppurative otitis media caused by A. terreus and its successful treatment and the review of the pertinent literature.

Case report

The patient was a male serviceman, 40 years of age, and a resident ofJabalpur, India. In 1990, he developed a fungal infection in the external and middle ear, with bilateral chronic suppurative otitis media. Subsequently, during the course of illness he attended several ENT clinics for treatment. On 5 May 1994 he attended a private ENT clinic at Jabalpur with the presenting symptoms of recur- rent ear discharge, itching, pain, mild deafness and heaviness in the ear. The patient had had perforation of the tympanic membrane since child- hood, but during routine follow-up fungal infection had been present in the right ear for the last 6 months .

Examination of the right ear revealed posterior- superior perforation without any trace of choleste-

298 S. TIWARI ET AL.

atoma. The left ear was unsafe and the patient had a history of cholesteatoma in this ear. The patient was operated for cholesteatoma at Medical College, Jabalpur, and modified radical mastoid- ectomy was done. The patient had recurrence of the lesion due to improper surgery. Revision mas- toid surgery with large meatoplasty was then undertaken at the private ENT hospital and since then the patient has had no problems.

Materials and methods

The biopsied specimen was aseptically collected in a sterilized tightly sealed bottle containing normal saline (0.85% NaCl) and immediately brought to the laboratory in a Thermos flask for processing. It was cut into two parts after being washed several times with sterile normal saline. A part of the biopsied mass was processed for direct microscopic detection of the fungal elements in mounts made in 10% KOH and lactophenol cotton blue solution. The rest was aseptically inoculated on Sabouraud glucose agar slants con- taining 0.05 mg ml-' chloramphenicol for the iso- lation of the aetiological agent. The slants were incubated at 28+ 1 "C for 2 weeks. The other part of the specimen was fixed in neutral formalin, dehydrated and later mounted in paraffin. Sections (8 pm) were cut and stained with Gomori's methenamine silver (GMS) stain.

'In vitro' susceptibility of A. terreus to antimycotics (itraconazole, ketoconazole, 5-fluorocytosine, clo- trimazole, amorolfine) was performed by a three- fold (1 : 3) dilution method [7] on Antifungal Assay Agar (AAA) (M164, Himedia, Bombay, India). All drugs except clotrimazole and 5-fluorocytosine (5-FC) were dissolved in dimethylsulphoxide (DMSO) and 1 : 3 stepwise diluted with distilled water. Dilutions of clotrimazole and 5-FC were prepared in distilled water directly. An inoculum was prepared from a 1 -week-old culture of A. terreus on AAA medium. Three loopfuls of the fungus were transferred into a flask containing 100 ml of sterilized distilled water. The suspension was mechanically homogenized by shaking thoroughly with sterilized glass beads and filtered aseptically through sterilized cheesecloth so as to separate the mycelium from the conidia. Using a haemocyto- meter the conidial count was adjusted to 2.7 x lo6 CFU ml-'. A 0.1-ml aliquot of the spore suspen- sion was inoculated aseptically into each AAA slant. The minimum inhibitory concentrations (MICs) of the drugs were recorded at 28i- 1 "C by visual observation in reference to the control after 24, 48 and 96 h of incubation. The MIC was defined as the lowest concentration of the drug

allowing no growth of the fungus in triplicate determinations.

Results

Direct microscopy of the clinical specimen in 10% KOH and lactophenol cotton blue-stained prep- arations revealed filamentous, branched single to irregularly aggregated large masses of hyphae. Histological sections of the biopsied tissue from the infected middle ear stained with GMS revealed dark-black aggregated mycelial elements in the infected tissue, which was stained light-brown against a pale-green background.

Aspergillus tmeus was isolated from the biopsied mass on Sabouraud glucose agar containing chlor- amphenicol on 14 May 1994. On Czapek's medium after 7 days of incubation the fungus showed very good growth at 37 "C, moderate growth at 28 "C and slow growth at 40 "C. All macro- and micromorphological properties fitted well with the standard description of A. terreus.

'In vitro' susceptibility testing of A. terreus showed that up to 24 h there was no growth of the organism on the control slants. However, full growth was seen at 48 h. Out of the antimycotics tested itraconazole gave the best result, with an MIC of 0.003 pg ml-', followed by ketoconazole with an MIC of 0.01 pgml-' after 48 h and 96h. Next in order were 5-fluorocytosine (0.03 pg ml-'), clotrimazole (1 pg ml-') and amo- rolfine (10 pg ml-') (Table 1). As itraconazole is not available commercially in India, the second most effective drug, ketoconazole ointment, was administered topically to the patient and treatment was successful. No recurrence of fungal infection was noted on routine follow-up.

Discussion

The role of fungi as pathogens in ear infections is becoming more widely recognized, and an

Table 1. 'In uitro' studies on the activity of antimycotics against Aspergillus terreus incubated at 28 +. 1 "C on Antifungal Assay Agar (AAA) medium after 48 h

Drug Inoculum size MIC (CF'U ml-') (Pg m1-l)

0.003 0.01 0.03

2.7 x 106 Itraconazole 2.7 x lo6 Ketoconazole

5-Fluorocytosine 2.7 x lo6 Clotrimazole 2.7 x lo6 1 Amorolfine 2.7 x lo6 10

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OTITIS MEDIA DUE TO ASPERGILLUS TERREUS 299

increased awareness of otitis of fungal origin may be partly responsible for this. There is now well- documented evidence of a real increase in the incidence of mycotic infections of the ear, partly as a paradoxical consequence of various clinical and therapeutic advances [8] and partly as a result of lifestyle changes, such as greater use of swim- ming pools and health spas; hot and humid cli- mates also favour ear infections. It is generally accepted that the fungi causing otitis are sapro- phytes or secondary invaders of skin affected by eczema, psoriasis, seborrhoeic dermatitis, previous bacterial infection, physical injury or excessive accumulation of cerumen [9].

Based on the isolation of the fungus from the clinical lesion and histological evidence of tissue invasion Aspergillus terreus was identified as the aetiological agent of the bilateral chronic suppurat- ive otitis media. Infections of the middle ear or mastoid may extend into the posterior fossa to involve the cerebellum or brain stem, leading to meningitis, paralysis of the face and even impaired vision in severe cases. It is also possible that the fungus may infect and erode the ear ossicles and thereby cause otitis interna. However, in the pre- sent case no such complications were apparent.

Both bacteria and fungi may be aetiological agents of otitis media. Ear examination under an operating microscope enables the physician to distinguish between bacterial or mycotic infection. In bacterial otitis, a moist epithelium can be seen with small white aggregations scattered evenly with odourless serous discharge [lo, 111. In the case of mycotic infection, a mycelial mat or plug with powdery deposits can be seen. On routine examination, when the mycelial aggregates are removed, the epithelium appears swollen and inflamed [lo-121. In the present case mycelial mats were seen in the inflamed and swollen epithelium.

Treatment of otitis media requires a combi- nation of aural toilet and topical medication with compounds that are selected largely empirically [ 131. Toilet should ideally be repeated daily [ 141. The presence of debris (damaged or diseased tissue) in the ear canal causes the accumulation of further debris in the ear canal, and this causes further inflammation, irritation and damage. Therefore, good treatment requires clearing of debris using an operating microscope and suction, paying particular attention to the anterior recess. This was done in the present case by the clinician.

It is important to stress the need to use an ear wick or gauze strip soaked with the antifungal compound, because this will provide a constant tissue contact with prolonged antifungal effect; it is especially important when there is perforation

of the tympanic membrane, as in the present case of otitis media caused by A. terreus. Oral antimy- cotic therapy was not particularly effective in the present case, perhaps because of poor blood supply at the site of infection and thus failure to achieve an appropriate concentration of the drug at that site. Successful topical treatment of the patient with ketoconazole ointment indicates the superior- ity of topical treatment in such cases. It is also recommended that treatment should be continued until all inflammatory signs have resolved and symptoms have abated [ 151. Although ketocona- zole was the second most effective drug after itraconazole in terms of ‘in vitro’ activity, the patient responded well to ketoconazole therapy and was cured.

The present case is an example of lack of clinical and laboratory concordance. The patient’s case history indicates that the ENT specialists are likely to misdiagnose chronic mastoiditis of fungal aeti- ology. This report should help to raise medical personnel’s awareness of such human opportun- istic fungal ear infections. This is, incidentally, the second case of chronic suppurative otitis media from India.

Acknowledgements

The authors wish to thank Dr S. K. Hasija, Professor and Head, Department of Biological Sciences, for providing laboratory facilities; and Janssen Pharmaceuticals Belgium, Squibb Sons, New Jersey, and Roche Pharmaceuticals, Switzerland, for providing free sample of the drugs.

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