LABORATORY IMPLEMENTATION OF A RAPID 3-STAIN TECHNIQUE FOR DETECTION OF MICROORGANISMS FROM LOWER RESPIRATORY SPECIMENS

A rapid, cost-effective method for the evaluation of lower respiratory specimen has become increasingly important in the diagnosis of pulmon ary diseases in immunocompromised patients. In the past, the technical ly demanding, time-consuming, and expensive Gomori-methenamine-silver (GMS) stain was the principal means for the evaluation of these specim ens. In this study, we compared the GMS stain with a new rapid, three- stain protocol for the evaluation of lower respiratory specimens. Lowe r respiratory specimens were obtained by bronchoalveolar lavage (BAL). Conventional Wright/Giemsa and Gram stains were utilized, as well as a contemporary strain, calcofluor white (CW). A cell count was perform ed on the BAL specimens, and cytospins were stained by the three stain s. The calcofluor white-stained slides were examined with an epi-fluor escent microscope, whereas the other stains were evaluated with a conv entional light microscope. Gomori-methenamine-silver (GMS), acid-fast bacillus (AFB), and Papanicolaou (PAP) stains were performed as contro ls. Thirty-two BAL procedures were performed in 20 (63%) male patients and 12 (37%) female patients. The clinical diagnosis was pneumonia in 31% of the patients, malignant hematologic disease in 28%, acute resp iratory distress syndrome (ARDS) in 9%, and acquired immunodeficiency syndrome (AIDS) in 28%. Of these specimens, 78% were adequate for inte rpretation and 22% were inadequate. Bacteria were found in 50% (16/32) of all BALs, fungi were found in 9% (3/32), and Pneumocystis carinii was found in 9% (3/32). Gram-positive bacteria were most frequently fo und in patients with pneumonia (80%, 4/5), whereas P, carinii was iden tified in patients with AIDS. There were no false-positive results. On e CW stain was equivocal for Fl carinii due to high fluorescent backgr ound, Laboratory implementation of the rapid, three-staining technique was accomplished without difficulty in microbiology and hematology la boratory sections. Specimen evaluation with the rapid staining protoco l was technically easy to perform; however, experience in ultraviolet fluorescent microscopy was crucial for interpretation of CW stain. All results were available in 2 hr, cost was reduced by 30%, and the assa ys were available 7 days/week. Further studies are ongoing to substant iate the sensitivity, specificity, and predictive value of this techni que, as well as clinical guidelines for its optimal utilization. (C) 1 996 Wiley-Liss, Inc.