[The pathogen spectrum in acute and chronic pleural empyema]

A retrospective analysis of the causative organisms was performed in 162 cases of empyema: 132/162 (= 81.5%) cases had positive cultures. Twenty-two different organisms were cultured from 235 isolates. The aerobic gram-positive bacteria were the largest group (61.7%), followed by aerobic gram-negative rods (21.7%), anaerobic bacteria (8.5%), and mycobacteria (5.1%). 1.8 bacterial species were recovered for each case of empyema. Polymicrobial empyema accounted for 48% of the cases. Therefore more than one antimicrobial agent should be administered to ensure adequate coverage.