Asporogenic anaerobic thoracic empyema--an experimental model for anaerobic thoracic empyema in rabbits

Abstract

Sterile pleural effusion was induced by intrapleural administration of turpentine, and empyema was induced by direct intrapleural inoculation of bacteria in rabbits. Experimental models of anaerobic thoracic empyema were successfully made in this study, using Escherichia coli, Peptostreptococcus asaccharolyticus, Bacteroides fragilis, using the following methods; (1) a single bacterium inoculation of, a) E. coli, b) P. asaccharolyticus, c) B. fragilis, (2) simultaneous inoculations with an aerobe and an anaerobe, a) E. coli + P. asaccharolyticus, b) E. coli + B. fragilis. (3) an anaerobic inoculation 5 days after an aerobic inoculation, a) P. asaccharolyticus inoculation 5 days after E. coli inoculation, b) B. fragilis inoculation 5 days after E. coli inoculation. The developments of several parameters (sialic acid levels, glucose levels, oxidation-reduction potential levels, bacterial counts and WBC counts in the pleural fluid and so on) were measured in each group. There was little difference of the rate of incidence of empyema between each group. Empyema was highly induced even by a single anaerobe inoculation. The following tendencies were observed in development of parameters: (1) sialic acid levels and oxidation-reduction potential levels were decreased only in the conditions being associated by B. fragilis infections. (2) in mixed infections of E. coli and anaerobes, bacterial counts of E. coli increased in number in the late phases of the infections probably by the influences of anaerobes. The experiments of groups (2) and (3) were designed for demonstrations of biphasic infections between aerobes and anaerobes, but it turned out that quite unexpected results were seen in these models.