Left thigh phlegmon caused by Nocardia farcinica identified by 16S rRNA sequencing in a patient with Leprosy: a case report

BMC Infectious Diseases Left thigh phlegmon caused by Nocardia farcinica identified by 16S rRNA sequencing in a patient with Leprosy: a case report Pasquale De Nardo 0 Maria Letizia Giancola 0 Salvatore Noto 1 Elisa Gentilotti 0 Piero Ghirga 0 Chiara Tommasi 0 Rita Bellagamba 0 Maria Grazia Paglia 0 Emanuele Nicastri 0 Andrea Antinori 0 Angela Corpolongo 0 0 Lazzaro Spallanzani National Institute for Infectious Diseases-IRCCS , Via Portuense 292, Rome 00149 , Italy 1 Azienda Ospedaliera Universitaria San Martino , Largo R. Benzi 10, Genoa 16132 , Italy Background: In recent years, Nocardia farcinica has been reported to be an increasingly frequent cause of localized and disseminated infections in the immunocompromised patient. However, recent literature is limited. We report a case of left thigh phlegmon caused by N. farcinica that occurred in a patient with Leprosy undergoing treatment with prednisone for leprosy reaction. Case presentation: We describe the case of left thigh phlegmon caused by Nocardia farcinica in a 54-year-old Italian man affected by multi-bacillary leprosy. The patient had worked in South America for 11 years. Seven months after his return to Italy, he was diagnosed with Leprosy and started multi-drug antibiotic therapy plus thalidomide and steroids. Then, during therapy with rifampicin monthly, minocycline 100 mg daily, moxifloxacin 400 mg daily, and prednisone (the latter to treat type 2 leprosy reaction), the patient complained of high fever associated with erythema, swelling, and pain in the left thigh. Therefore, he was admitted to our hospital with the clinical suspicion of cellulitis. Ultrasound examination and Magnetic Resonance Imaging showed left thigh phlegmon. He was treated with drainage and antibiotic therapy (meropenem and vancomycin replaced by daptomycin). The responsible organism, Nocardia farcinica, was identified by 16S rRNA sequencing in the purulent fluid taken out by aspiration. The patient continued treatment with intravenous trimethoprim/sulfamethoxazole and imipenem followed by oral trimethoprim/sulfamethoxazole and moxifloxacin. A whole-body computed tomography did not reveal dissemination to other organs like the lung or brain. The patient was discharged after complete remission. Oral therapy with trimethoprim/sulfamethoxazole, moxifloxacin, rifampicin monthly, clofazimine and thalidomide was prescribed to be taken at home. One month after discharge from the hospital the patient is in good clinical condition with complete resolution of the phlegmon. Conclusion: N. farcinica is a rare infectious agent that mainly affects immunocompromised patients. Presentation of phlegmon only without disseminated infection is unusual, even in these kinds of patients. In any case, a higher index of suspicion is needed, as diagnosis can easily be missed due to the absence of characteristic symptoms and the several difficulties usually encountered in identifying the pathogen. Nocardia; Hansen's disease; Phlegmon - Background Nocardiosis is a localized or disseminated uncommon infection caused by an aerobic Actinomycetes of the genus Nocardia [1]. Approximately 50 species of Nocardia have been characterized [2], with at least 16 species being recognized as human pathogens [3]. These organisms are opportunistic pathogens affecting immunocompromised hosts, including those with long-term corticosteroid exposure, malignancy, human immunodeficiency virus infection, and a history of transplantation [4]. Earlier reports estimated the occurrence of 5001,000 new cases each year in the USA, and 150200 and 90130 in France and Italy, respectively [5-7]. N. asteroides, N. farcinica and N. nova caused approximately 85% of the total cases [8-10]. An increase in the diagnosis of N. farcinica infection is due to the growing population of immunocompromised hosts and improved methods for detecting and identifying the Nocardia species. This microorganism can cause localized or disseminated infections that can be life-threatening without prompt diagnosis and proper treatment; furthermore, it is characteristically resistant to multiple anti-microbial agents, including third-generation cephalosporin [1,11]. We report the case of left thigh phlegmon caused by N. farcinica that occurred in a patient affected by Leprosy undergoing treatment with prednisone for leprosy reaction. Case presentation A 54 year old Italian man was admitted to the Lazzaro Spallanzani National Institute for Infectious Diseases of Rome because of fever, cutaneous lesions and sensory loss of peripheral nerves. He had worked in Venezuela for eleven years. A histological examination of a skin biopsy showed the presence of Mycobacterium leprae and the patient was diagnosed as borderline lepromatous (BL) leprosy complicated by erythema nodosum leprosum (ENL) reaction. His bacteriological index (total bacterial load) was 4.17+ (normal range 0-6+) and the morphological index (percentage of bacilli uniformly stained) 0.5%. He was treated with rifampicin monthly and minocycline and moxifloxacin daily. The ENL was recurrent and treated with oral prednisone (75 mg) and thalidomide. Sixteen months after starting therapy for Leprosy (and after about a year of steroid therapy), the patient started to complain of high fever (39C) associated with erythema, swelling and pain of left thigh, and he was admitted to our hospital for the second time with suspicion of cellulitis. He referred that the symptoms had started about 7 days before admission, but he denied a history of local trauma or recreational drug abuse. Diabetes mellitus had been diagnosed two months before. On physical examination, his vital signs were as follows: temperature 39C, blood pressure 130/80 mmHg, pulse rate 95 beats per minute, and respiratory rate 15 breaths per minute. Laboratory examinations revealed: white blood cells (WBC) 14,500/L (4,3-10,8) (87% neutrophils, 4.1% lymphocytes), haemoglobin 11 g/dL (1218), platelets 234,000/L (80,000 400,000), C-reactive protein (CRP) 32 mg/dL (00.16), and erythrocyte sedimentation rate (ESR) 82 mm/h (015). Chest X-ray was normal. Ultrasound examination and Magnetic Resonance Imaging (MRI) of the lower extremities revealed left thigh phlegmon (Figure 1). Ultrasound guided incision and drainage were performed at the bedside with leaking, copious amounts of pus. Samples were sent to the laboratory for Gram and acid -fast bacilli staining, cultures, and PCR amplification of bacterial DNA. Furthermore, more sets of blood cultures were performed. Intravenous vancomycin and meropenem were started: 500 mg every six hours, and 1 g every 8 hours, respectively, and moxifloxacin and minocycline were stopped. Incision was repeated on hospital day 3 and vancomycin was replaced by daptomycin for the persistence of high fever; prednisone was reduced to 50 mg. After 96 hours of incubation, blood cultures and aerobic and anaerobic cultures of the sample were negative. On day 6, the patient had type 2 (...truncated)