Clinical experiences of pulmonary and bloodstream nocardiosis in two tertiary care hospitals in northern Taiwan, 2000-2004

Background and Purpose: Nocardia is an uncommon pathogen in humans, and most patients with nocardiosis are immunocompromised, with variable etiologies. To understand the incidence, clinical characteristics, treatment and outcome of pulmonary and bloodstream nocardiosis, we conducted a retrospective study in two tertiary care hospitals in northern Taiwan. Methods: We reviewed laboratory culture reports and clinical records of 29 adult patients with lower respiratory tract or bloodstream nocardiosis (21 and 8 patients, respectively) in two tertiary care hospitals, over a period of 5 years. The risk factors, clinical manifestations, response to therapy, outcome and recurrence rate were compared between these two groups. Results: The most common underlying conditions in pulmonary nocardiosis were chronic lung disease and long-term steroid usage. For nocardemia, underlying malignancy and steroid administration are common. Fourteen of 21 patients with pulmonary nocardiosis ever transferred to an intensive care unit and 9 of them had concomitant infection. In patients with and without coexisting isolates during hospital course, the mean days from admission to specific therapy for nocardiosis were 26.4 and 11.9 days, respectively. Patients with nocardemia showed great variation in clinical manifestations and disease severity; central venous catheter implantation was noted in 6 of them. Only one patient with nocardemia had documented recurrence. Twenty four patients were treated with antimicrobials (trimethoprim- sulfamethoxazole, 83%; imipenem or meropenem, 25%). Treatment failure occurred in 7 of 20 patients treated with trimethoprim-sulfamethoxazole alone or in combination. Conclusions: Pulmonary or disseminated nocardiosis is rare but may be fatal as an opportunistic infection in an immunocompromised host with chronic lung disease, underlying malignancy or long-term steroid usage. The significance of primary nocardemia needs careful evaluation. Concomitant infection was the probable predisposing factor for intensive care unit admission for pulmonary nocardiosis in our study (p=0.019) and might obscure the isolation of nocardiae organisms and delay effective treatment. For critical patients with nocardiae infection, initial therapy with a combination antimicrobial regimen is recommended.