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Journal of Postgraduate Medicine, Vol. 49, No. 4, Oct-Dec, 2003, pp. 322-324 Case Report Mycetoma Caused by a New Red Grain Mycetoma Agent in Two Members of a Family Maiti PK, Bandyopadhyay D, Dey JB, Majumdar M
R. G. Kar Medical College, Kolkata - 700004 Code Number: jp03089 An 18-year-old woman from rural West Bengal was affected with mycetoma involving her neck, back, and chest. After an interval of eight years, her younger brother developed mycetoma on his left arm. No history of trauma or immune deficiency was present in either case. By microscopic examination of sinus-discharged materials from both the cases, identical rusty red, hard grains were demonstrated. Soluble red pigment-producing colonies grew in Sabouraud dextrose-agar medium. Isolates were positive for casein hydrolysis and negative for hydrolysis test of xanthine, hypoxanthine, tyrosine, and nitrate reduction. Thus it differed from the only known red grain mycetoma agent, Actinomadura pelletieri and was provisionally identified as Actinomadura vinacea. Familial affection in mycetoma, that too caused by a new agent, is reported here for its uniqueness. Key Words: Mycetoma, Red grain, Actinomadura sp., Family history. Mycetoma is a subcutaneous mycosis, clinically characterised by indolent, deforming, swollen lesions and sinuses involving cutaneous and subcutaneous tissues, fascia and bones, usually occurring on a foot or hand.[1] The draining sinuses, when expressed, discharge numerous small particles or granules (grains). The colour of the grains varies depending on the aetiologic agent. This clinical syndrome is caused by a wide variety of filamentous bacteria (actinomycotic mycetoma, actinomycetoma) or fungi (eumycotic mycetoma, eumycetoma). The saprophytic forms of the causal agents are present in the soil or plants. At least 10 geophilic actinomycetes[1] are reported to cause actinomycetoma but many more similar organisms are known without pathogenic significance. Actinomadura pelletieri is so far the only known red grain mycetoma agent.[2],[3] We report the occurrence of two cases of red grain mycetoma caused by a new mycetoma agent that involved two members of a family at an interval of eight years, with a possible explanation for the mode of transmission in these cases. Familial affection in mycetoma, that too caused by a new agent, is reported here for its uniqueness. An 18-year-old man, a barber by occupation, developed a painless, firm swelling on the middle third of his left arm [Figure-2] in September 2000. Gradually, nodules and discharging sinuses evolved on the swelling. There was no history of obvious trauma at the site of the lesion. The lesions were painless, non-tender, and non-pruritic. Examination revealed a large area of induration covering the medial aspect of the left arm. The indurated area was studded with papules and sinus tracts, the openings of which were slightly raised. Discharge from the sinus tracts contained scanty sanguinous fluid without visible grains. There was no lymphadenopathy. The results of the Mantoux test, chest X-ray, serological test for human immunodeficiency virus (HIV), and histological examination of the biopsied tissue were non-contributory. There was no radiological abnormality of the involved part. By direct microscopic examination of potassium hydroxide (KOH) smear of expressed discharge from impending sinuses, reddish, oval, brittle, hard grains with a diameter of 300-500m were revealed. The hard grains broke into tile-shaped pieces on pressure through the coverslip [Figure-3]. Culture in Sabouraud's dextrose-agar (SDA) medium at 370C yielded dirty red, brittle, dry, granular clumps of colonies within seven days, with red diffusible pigment around the colonies. Moderately branched Gram positive aerial mycelia with a few short straight chains of arthrospores were detected in Gram-stained culture smear. The organism showed rapid casein hydrolysis with diffusible red pigment production, but xanthine, hypoxanthine, tyrosine and nitrate reduction tests were negative. The patient showed slow improvement in the last two months with a combination regimen of cotrimoxazole, streptomycin and doxycycline. About eight years ago, the elder sister of this patient, an embroidery worker by occupation, had developed mycetoma involving her back, left side of the neck, and anterior chest wall [Figure-1]. Grain morphology, cultural characteristics, and biochemical features identical to those in the present case had been demonstrated and the case was reported in the year 2000.[4] Both the isolates were provisionally identified as Actinomadura vinacea, a known soil saprophyte appearing to emerge as a new actinomycotic agent. Irrespective of the causative agents, mycetoma presents with the same clinical features. Examination of grains alone often permits differen tiation of actinomycetoma from eumycetoma.[1] For institution of effective therapy, however, culture and laboratory identification are indicated since actinomycetoma are more amenable to drugs than are eumycetoma.[1],[3] Of the mycetoma agents, Actinomadura. pelletieri and occasionally A. madurae produce prodigiosin-like endopigments.[5] The red endopigment is responsible for the red colour of their grains and colonies. No human actinomycetoma agent has been reported to produce soluble pigment in culture medium. In this respect the present isolate is a unique one. Amongst different soil isolates described,[6],[7] A. vinacea closely resembles this new actinomycetoma agent. Two members of one family were affected by the condition, which indicates that this organism is not only a soil saprophyte but also a potential human pathogen. There were no familial cases in the series of 264 mycetomas reported from West Bengal.[8] Since the incidence of the disease is related to the risk of trauma and wound contamination by the saprophytic form of the infectious bodies of the causal agents, and not their tissue forms, no epidemic or outbreak of mycetoma by the same causal agent, or any incidence of the disease among several members of a family is reported. In the present cases, although there was no common occupational risk factor, there was scope for repeated exposure to the infectious saprophytic form of the organism from the earlier case to the later one. The organism coming through the discharge of the sinuses on the back or neck region of the first case probably contaminated bedding and linen, where it persisted and converted into the saprophytic form. Through microinjuries like scratches or abrasions, the second patient might have contracted the infection. Thus it reappeared as another mycetoma by the same rare organism after an interval of eight years.
Copyright 2003 - Journal of Postgraduate Medicine. Online full-text also available at http://www.jpgmonline.com/ The following images related to this document are available:Photo images[jp03089f2b.jpg] [jp03089f1.jpg] [jp03089f3.jpg] |
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