Abstract
Reactivation of latent infection is considered to be the main mechanism underlying the development of Pneumocystis pneumonia in immunosuppressed patients. We retrospectively assessed the effects of the prophylactic administration of sulfamethoxazole-trimethoprim on the development of Pneumocystis pneumonia and airway colonization with Pneumocystis jirovecii in patients undergoing examinations to diagnose or rule out Pneumocystis pneumonia. Polymerase chain reaction was performed to detect Pneumocystis jirovecii using bronchoalveolar lavage fluid or sputum of 60 consecutive patients between 2004 and 2012. Not all of the patients who received the prophylactic administration of sulfamethoxazole-trimethoprim (n=10) developed Pneumocystis pneumonia or demonstrated airway colonization with Pneumocystis jirovecii, and none of the patients who developed Pneumocystis pneumonia (n=11) or showed colonization (n=9) had received prophylactic treatment. Furthermore, 20 (40%) of 50 patients without prophylactic treatment showed positive results on the Pneumocystis jirovecii DNA polymerase chain reaction, but all of 10 patients with prophylactic treatment showed negative results on it (Fisher's exact test, p=0.02). Therefore, the prophylactic administration of sulfamethoxazole-trimethoprim has possibilities to be effective in preventing Pneumocystis pneumonia as well as eliminating airway colonization with Pneumocystis jirovecii. Further studies targeting large cohorts of patients with a variety of underlying diseases are required to develop recommendations regarding the prophylactic administration of sulfamethoxazole-trimethoprim.
