Pneumocystis jirovecii colonization in chronic pulmonary disease.

Pneumocystis jirovecii causes pneumonia in immunosuppressed individuals. However, it has been reported the detection of low levels of Pneumocystis DNA in patients without signs and symptoms of pneumonia, which likely represents colonization. Several studies performed in animals models and in humans have demonstrated that Pneumocystis induces a local and a systemic response in the host. Since P jirovecii colonization has been found in patients with chronic pulmonary diseases it has been suggested that P jirovecii may play a role in the physiopathology and progression of those diseases. In this report we revise P. jirovecii colonization in different chronic pulmonary diseases such us, chronic obstructive pulmonary disease, interstitial lung diseases, cystic fibrosis and lung cancer.

Pneumocystis jirovecii infection in patients with acute interstitial pneumonia. / Infección por Pneumocystis jirovecii en pacientes con neumonía intersticial aguda.

OBJECTIVE: Acute interstitial pneumonia (AIP) is a severe disease of unknown etiology. Pneumocystis jirovecii is an atypical opportunistic fungus able to colonize patients with chronic pulmonary disease and inducing alveolar macrophage activation. The aim of this study was to evaluate the possible association between Pneumocystis jirovecii and AIP. SUBJECTS AND METHODS: The presence of P. jirovecii in bronchoalveolar lavage fluid in the four confirmed cases of AIP identified in a tertiary-care hospital over a period of nine years was studied using a 2-step nested-PCR protocol assay. RESULTS: P. jirovecii was identified in the four cases. None of them had HIV infection. Two of the patients were treated empirically with trimethoprim-sulfamethoxazole, the only survivor was being one of them. CONCLUSIONS: Our data suggest that Pneumocystis could trigger or favor the development of AIP. Further studies are needed to evaluate the role of the pathogen in the physiopathology of this disease.