Challenges in diagnosis and management of infective endocarditis by Stenotrophomonas maltophilia: A case report of an unusual nosocomial infection

Stenotrophomonas maltophilia is a Gram-negative bacillus found as a free-living organism in most aquatic and humid environments including hospital drinking water, and often associated with nosocomial infections. It is an uncommon cause of infective endocarditis. In Sri Lanka there are no reported cases in literature. Here we report a 46 years old patient who presented with fever following Percutaneous Trans Mitral Commissurotomy (PTMC). He was diagnosed as an acute mitral valve endocarditis based on echocardiograph findings and 2 blood cultures taken 6 hours apart which grew Stenotrophomonas maltophilia. The patient responded rapidly to targeted antibiotic treatment with piperacillin tazobactam and oral cotrimoxazole for 4 weeks and a further 2 weeks of cotrimoxazole. He remained well at the 3 month follow up. There is limited information on the best choice of antibiotics and the ideal duration of treatment. Early diagnosis and identification of the organism, prompt treatment with appropriate antibiotics and close collaboration between the clinical and laboratory teams contributed towards the successful management of this case.