[New aspects of epidemiology and treatment of Pneumocystis carinii infection].

Pneumocystis carinii is an opportunistic eukaryotic pathogen most common causing pneumonia in immunocompromised host. DNA P. carinii f. sp. hominis has been frequently detected in air samples collected from environments of P. carinii pneumonia (PCP) patients and nasal swabs samples from contact health care workers and family. Epidemiological studies suggested not-only the possibility of person-to-person infection transmission. First hypothesis of reactivation latent infection of the causing the new episode of PCP based on serological studies. Recently findings based molecular studies has suggested new acquired infection may to be cause of many cases of PCP. Early diagnosis, therapy and effective prophylaxis of PCP is a very important strategy to reduce morbidity and mortality among infected patients. The combination of trimethoprim (TMP) and sulfamethoxazole (SMX) is effective for prophylaxis and treatment P. carinii pneumonia. Empiric therapy in immunocompromised host also including AIDS patients with anti-Pneumocystis prophylaxis is also not recommended. Both dapsone and sulfamethoxazole act inhibiting the folate biosynthetic enzyme DHPS. Mutations identified in P. carinii in gene coding this enzyme are associated with resistance to sulfonamide. P. carinii may also developing resistance to atovaquone, second-line therapeutic and prophylactic agent.