[Comparison of 3 tests for the diagnosis of pulmonary pneumocystosis in AIDS patients].
Since Pneumocystis jiroveci cannot be grown in vitro, laboratory diagnosis of pulmonary pneumocystosis (PCP) has been based mainly upon microscopy. The usefulness of 3 diagnostic methods of PCP was compared in 111 bronchoalveolar fluids belonging to an equal number of AIDS patients assisted in different wards of the Muñiz Hospital. Wet mount preparations, a rapid modification of Grocott technique and the direct immunofluorescence (DIF) with monoclonal antibodies were compared for the diagnosis of PCP on smears of clinical samples. Similar results (15 positive and 90 negative) were obtained with these three techniques in 105 (93.6%) of the studied samples; in 3 (2.7%) cases the DIF was positive while the other techniques were negative, and in other 3 (2.7%), the Grocott stain was negative when the other two techniques were positive. In the investigated samples, due to the abundance of P. jiroveci, the searching of "honeycombs" structures in wet mount preparations is perfectly adaptable as screening test. The Grocott stain showed to be useful for the diagnosis of other mycoses, and the DIF, due to its high cost, can be employed when the other techniques are negative.