pathogen by BAL, bronchial washing or lung tissue. This 
will include: 
1. Bacterial pneumonia will be diagnosed by 
identifying a culture yielding moderate to many 
colonies of a single or predominant organism or 2; 
103/ml for a pure culture or ^ 105/ml for a mixed 
culture, or by the identification of Legionella or 
mycobacterial species on BAL, or any organism on 
biopsy tissue. 
2. Fungal pneumonia will be diagnosed by the 
identification of a culture yielding moderate to 
many colonies or ^ 103/ml of Candida, or septate 
hyphal elements (e.g. Aspergillus) with > one 
colony identified on culture in BAL, or any [] 
hyphal fungi Q on biopsy tissue. 
3. Pneumocystis pneumonia will be diagnosed by the 
presence of pneumocystis on BAL [j. 
4. Viral pneumonia will be diagnosed by the presence 
of a positive culture, FA or characteristic viral 
inclusions on BAL or biopsy tissue. 
0 
Idiopathic pneumonia will be defined by a new or 
progressive diffuse infiltrate on CXR (by retrospective 
review) and examination of lung tissue or BAL that has a 
negative evaluation for microbiologic causes. 
Other organ site-specific infection 
1. Esophagus requires histologic evidence of invasive 
hyphal elements. Bacterial esophagitis will not be 
included. 
2. Liver, spleen, kidneys, brain will require aspiration 
or biopsy evidence for infection. 
Sterile closed space infection (e.g. CNS, peritoneal, pleural) 
A Hickman catheter infection is defined as local erythema 
at the exit site with purulent drainage positive for a single 
or predominant organism and/or inflammation (including 
redness and tenderness) at least 1 cm or more up the line 
from the exit site or at any other point along the tract with 
an associated positive blood culture in the absence of a 
Recombinant DNA Research, Volume 16 
