Comparison of bacteria isolated from specimens obtained by use of endoscopic guarded tracheal swabbing and percutaneous tracheal aspiration in horses.

Results of bacteriologic culture of specimens obtained from 14 horses with pneumonia and from 15 horses that were clinically healthy (nonpneumonia group) were compared. Specimens were obtained by use of an endoscopic guarded tracheal swabbing method and percutaneous tracheal aspiration. The percentage of agreement between the 2 tracheal specimens for the horses of the pneumonia group was 79% for aerobic isolates and 100% for anaerobic isolates. The percentage of agreement between results of the 2 tracheal specimens for horses of the nonpneumonia group was 80% for aerobic organisms and 93% for anaerobic organisms. The endoscopic guarded swabbing method described here for obtaining specimens from the lower airways for bacteriologic culture did not always prevent contamination. Results of the study suggested that this endoscopic swabbing technique has merit and should be considered as an alternative to the tracheal aspiration method. Pseudomonas sp and any anaerobic bacteria that are isolated must be viewed as potential contaminants of the endoscopic swab specimen and may not be involved in the primary pulmonary disease.