SUCCESFULL TREATMENT OF PULMONARY NOCARDIOSIS WITH LINEZOLID

Nocardiosis is an opportunistic infection, with high mortality especially in immunocompromised patients. Up to one-third of patients with nocardiosis, however, are immunocompetent and the occurrence of the disease in these patients especially with chronic obstructive pulmonary disease (COPD) as the present case, can delay diagnosis and lead to rapidly respiratory failure. A 82-years-old men, affected by COPD and chronic HBV-related hepatitis, was admitted in November 2012 to a regional hospital because of fever and cough (July 2012), with temporary benefit from a previously prescribed antibiotic treatment. He underwent chest High-Resolution-TC (HRTC) which showed lower left lobe pneumonia and was treated with ceftriaxone, with subsequent apyrexia. After discharging fever and cough relapsed and he was again admitted in hospital. HRTC showed widespread focal areas of pneumonia and a bronchoscopy was performed. Bronchial washing culture showed Nocardia spp colonies, but microbial identification was not done. A therapy with trimethoprim-sulphamethoxazole (TMP-SMX, TMP 240 mg-SMX 1200 mg TID) intravenously (i.v) was started, with initial slow improvement of clinical conditions, followed by relapse of fever and increasing values of white blood cells and reactive-C-protein (RCP, 15.2 mg/dl). The patient was thus admitted at our Institution in January 2013 and antibiotic therapy was intensified (TMP 240 mg-SMX 1200 mg QID plus amikacin 1 g QD i.v). Clinical conditions improved and WBC and RCP values decreased. A lung TC showed no differences with the previous one. After 2 weeks he developed respiratory failure; a chest x-rays showed a significant widespread pneumonia and RCP values increased; amikacin was ended and meropenem 4g daily i.v was started. One week after, no clinical, laboratory or radiologic improvement was observed; TMP-STX was discontinued and Linezolid 1200 mg daily i.v was started. Respiratory failure rapidly disappeared. After two weeks of treatment, clinical conditions markedly improved, RCP values decreased and radiological findings were less extended. Therapy is still ongoing. This will be switched orally and continued for 4-6 months, according to clinical and radiological findings. Optimal antimicrobial treatment regimens for nocardiosis have not been firmly established. Moreover, as described for N. farcinica in Northern Italy, resistance to first-line regimens can occur, but most laboratories are not able to identify species and perform antibiogram, thus therapy can be quite empiric. TMP-SMX resistance, as this case remarks, can develop in vivo after initial effective treatment. Linezolid administration has been successfully reported for brain abscess and pneumonia caused by different Nocardia spp, because of its efficacy and good penetration in lung and CNS. Oral formulation is useful for long-lasting treatment as required, although bone-marrow and neurologic toxicity must be carefully evaluated.