mycoses 45, 512–514 (2002)
Accepted: June 28, 2001
Letter to the Editor
Case Report. Keratomycosis due to Alternaria alternata in a diabetic patient Fallbericht. Keratomykose durch Alternaria alternata bei einem Diabetiker Loranne Vella Zahra1, D. Mallia2, J. Grech Hardie2, A. Bezzina2 and T. Fenech2 Key words. Alternaria alternata, keratomycosis, diabetes, Malta. Schlu¨sselwo¨rter. Alternaria alternata, Keratomykose, Diabetes, Malta.
Summary. A case of keratitis caused by Alternaria alternata in a diabetic male, after traumatic corneal injury with a sharp object, is described. The patient was treated with topical amphotericin B solution and a full uneventful recovery was achieved. This is the first reported case of fungal keratamycosis in Malta, which was substantiated with both positive direct microscopy and a positive culture of the fungus. Zusammenfassung. Ein Fall von Keratitis bei einem Diabetiker, verursacht durch Alternaria alternata nach einer traumatischen Hornhautverletzung, wird beschrieben. Der Patient wurde mit topischer Amphotericin B-Lo¨sung behandelt, und volle Ausheilung wurde erreicht. Das ist der erste Bericht einer Keratomykose in Malta, der mit direkter Mikroskopie und positiver Pilzkultur gesichert ist. Introduction Alternaria alternata is a dematiaceous hyphomycete which is ubiquitous as a saprophyte in the environment, especially in soil and decomposing vegetation. It is a known agent of ocular infections and has been reported to cause both keratitis and also 1
Mycology Laboratory, Pathology Department, and 2Department of Ophthalmology, Medical School, St. Luke’s Hospital, Malta. Correspondence: Ms. Loranne Vella Zahra, Clinipath Medical Laboratories, Mycology Laboratory, 217/3 Marina Street, Pieta´ MSD OB Malta. E-mail:
[email protected]
endophthalmitis [1–4]. The most common predisposing factor appears to be trauma; this is especially evident in patients who have an outdoor occupation such as agricultural or outdoor manual workers [2, 5, 6]. These patients are often exposed to accidental corneal trauma due to soil or plant material. We report a case of a man with keratitis due to A. alternata after traumatic injury of his left eye with a foreign body. Case history A 55-year old married man was referred with a 3-day history of moderate pain in his left eye, a mild stinging sensation, moderate photophobia and redness and a moderately increased lacrimation. The patient complained that he was unable to sleep at night due to a feeling of great discomfort. On examination, there was no foreign body in the eye. The patient explained that while he was working in his fields, he had suddenly felt something prickly enter his left eye and he had instinctively rubbed his eye. The patient had a family history of diabetes, his parents having been both diagnosed with the disease; he had had diabetes mellitus since 1981 and it was being well controlled by oral hypoglycaemic agents. The patient also had asthma and used to smoke cigarettes in the past but gave up smoking recently. Other relevant past medical history included an incident in 1996, when he was hit by lead shot on the left upper eyelid. In this event, no injury was located in the eye itself except some burns on the inner canthus and there was a
Keratomycosis due to A. alternata
Figure 1. Grocott’s methenamine silver stain of corneal scrapings showing dematiaceous septate hyphae.
purulent conjunctivitis. The lead shot appeared to be embedded in the periorbital fat tissue and did not budge with eye movement. On fundoscopy, no intra-ocular foreign body was observed; his visual fields were full and within normal limits. The patient reported only mild photophobia and some swelling. On this occasion, he was given cephalexin 500 mg every 6 h and instructed to apply topical gentamicin every 2 h. In the case under review, the patient was admitted and given gentamicin eyedrops every 1 h. The following day there was no improvement at all in the symptoms and a corneal scraping was taken at the bedside of the patient and directly inoculated onto the appropriate culture media. Two smears were also prepared on clean glass slides for direct microscopy. A Gram stain and a Grocott methenamine silver stain were carried out on the two smears and both showed abundant septate hyphae; in the case of the Grocott-stained smear, the hyphae were brown-black in appearance (Fig. 1). Culture on Sabouraud glucose agar at 30 °C yielded Alternaria alternata within 3 days of incubation. Amphotericin B (50 mg) for injection was diluted with 10 ml of sterile water for injection; subsequently, 3.5 ml of this solution were further diluted with 6.5 ml of 5% glucose. The patient was instructed to administer 1 drop of the final amphotericin B dilution (1.75 mg ml)1) into the affected eye every 4 h for 4 weeks. A new solution was prepared every 5 days and placed in an amber bottle. The patient did well with the amphotericin eyedrops and recovered fully without any complications. The patient was reviewed again 1 month after the episode and was found well. Discussion Most ocular infections ensue from direct trauma to the eye, previous ocular surgery, and the indiscreet mycoses 45, 512–514 (2002)
513
use of topical antibacterial antibiotics and corticosteroids [2, 4]. Keratomycosis appears to be more common in tropical areas, accounting for up to 50% of cases of microbial keratitis in India, and in temperate climates it is generally seen in rural regions [7]. Men seem to be more commonly affected than women and again, this is probably related to a greater proportion of outdoor workers being men [2, 5]. Various fungi have been reported to be responsible but especially Aspergillus, Fusarium, Penicillium and Candida species. Moreover, several dematiaceous fungi may be involved in keratomycosis such as Alternaria, Curvularia, Bipolaris, Exophiala jeanselmei, Exserohilum, Phialophora and Wangiella dermatitidis [8]. This is the first case report of Alternaria alternata keratomycosis in Malta, with both microscopic and cultural evidence of a mycotic involvement. Our patient frequently worked outdoors and therefore, was often in contact with soil and other environmental material. In fact, our patient gave a history of feeling a foreign body in his eye which could have been a wood splinter, an insect or soil debris (we never managed to obtain enough data to identify the injuring object). Such material is the most likely source of fungal spores which could have either been directly implanted into the cornea or the foreign body may have caused corneal abrasion and the cornea, thus damaged, was then more easily exposed to infection. In addition, the patient received topical gentamicin for at least 24 h and such blanket use of antibiotics may have further predisposed our patient to fungal infection. The fact that he was diabetic may have also helped to increase his risk of developing a fungal infection following his traumatic episode. Finally, the present case further shows the importance of demonstrating fungal elements on microscopic examination of smears as convincing evidence of infection together with culture of the fungus in question. References 1 Wenkel, H., Rummelt, V., Knorr, H. & Naumann, G. O. (1993) Chronic postoperative endophthalmitis following cataract extraction and intraocular lens implantation. Report on nine patients. Ger. J. Ophthalmol. 2 (6), 419– 425. 2 Chander, J. & Sharma, A. (1994) Prevalence of fungal corneal ulcers in northern India. Infection 22 (3), 207–209. 3 Arrese, J. E., Pierard Franchimont, C. & Pierard, G. E. (1996) Onychomycosis and keratomycosis caused by Alternaria sp. A bipolar opportunistic infection in a wood-pulp worker on chronic steroid therapy. Am. J. Dermatopathol. 18 (6), 611–613.
514
L. Vella Zahra et al.
4 Panda, A., Sharma, N., Das, G., Kumar, N. & Satpathy, G. (1997) Mycotic keratitis in children: epidemiologic and microbiologic evaluation. Cornea 16 (3), 295–299. 5 Venugopal, P. L., Venugopal, T. L., Gomathi, A., Ramakrishna, E. S. & Ilavarasi, S. (1989) Mycotic keratitis in Madras. Indian J. Pathol. Microbiol. 32 (3), 190–197. 6 Mino de Kaspar, H., Zoulek, G., Paredes, M. E., et al. (1991) Mycotic keratitis in Paraguay. Mycoses 34 (5–6), 251–254.
7 Richardson, M. D. & Warnock, D. W. (1997) Keratomycosis. In: Richardson, M. D. & Warnock, D. W. (eds), 1 Fungal Infection – Diagnosis and Management. Oxford: Blackwell Science Ltd, pp. 107–110. 8 Forster, R. K., Rebell, G. & Wilson, L. A. (1975) Dematiaceous fungal keratitis: clinical isolates and management. Br. J. Ophthalmol. 59, 372–376.
mycoses 45, 512–514 (2002)
