P041 A fishy diagnosis in the immunocompromised patient
Authors: Preece Bethan , Edwards Siwan , Jenkins Charlotte , Hughes Jennifer 
Published: April 2022

Abstract

Background/Aims
Immunocompromised patients are at risk of developing opportunistic infections. Mycobacterium marinum is an atypical bacterium that is found in bodies of fresh or salt water. Skin infections with Mycobacterium marinum are relatively uncommon and are usually acquired by direct inoculation through broken skin following contact with aquariums or fish. Infection with this bacterium can present with chronic cutaneous lesions, tenosynovitis, septic arthritis, and rarely osteomyelitis. This case emphasises the importance of educating immunocompromised patients with regards to good skincare to prevent inoculation with opportunistic infections.

Methods
We present the case of a patient with Behcets disease, immunosuppressed with prednisolone, methotrexate and infliximab who presented on a number of occasions with ‘recurrent cellulitis’. Following repeated re-presentations with worsening cutaneous manifestations, specialist review was arranged, and ultimately Mycobacterium marinum was confirmed on tissue culture.

Results
A 46-year-old nurse, known to the rheumatologist with Behcets disease presented to clinic with new skin lesions affecting her right hand and arm that progressed over a period of 4-months. Initially she noticed intact blisters affecting the fourth finger of her right hand. She subsequently developed painful localised erythema and swelling overlying the third MCPJ which didn't respond to oral antibiotics. She re-attended her local hospital for intravenous flucloxacillin for cellulitis. Septic arthritis was excluded. She did not have any systemic signs of infection and her inflammatory markers remained normal. Oral antibiotics were continued without clinical response and Infliximab and Methotrexate withheld but she remained on 15mg of prednisolone. In the subsequent weeks she developed new cutaneous lesions extending up her right forearm in a spirotrichoid distribution. Further questioning revealed she had recently acquired tropical fish which became unwell and suddenly died. She was reviewed by the dermatologist and tissue biopsy confirmed the diagnosis of Mycobacterium marinum. She was started on ethambutol and azithromycin and within 3-months the cutaneous granulomas resolved. She remained off infliximab and methotrexate until the lesions had resolved but her Behcets flared despite prednisolone, with evidence of synovitis, fatigue and bowel symptoms. Reintroduction of her immunosuppression hasn't resulted in any recurrence of the granulomas.

Conclusion
Immunocompromised patients are at risk of developing opportunistic infections. This case demonstrates the importance of acquiring a full history including exposure to pets when such infections are considered. We don't routinely council counsel patients with regards to avoidance of water contact or using gloves for persons with open skin lesions. We should be promoting good skin hygiene in all immunocompromised patients. Mycobacterium marium should always be considered in patients with lesions of a sportorichoid nature, most often at the site of an open abrasion on their dominant hand. Systemic signs of infection are rare however immunosuppressed individuals are at higher risk of developing disseminated infection.

Disclosure
B. Preece: None. S. Edwards: None. C. Jenkins: None. J. Hughes: None.