Anaerobic bacteriology in 75 cases of thoracic empyema in Sofia, Bulgaria

The aim of this study was to evaluate the prevalence of anaerobes in patien ts with thoracic empyema over a period of 30 months and to assess the susce ptibility of the isolates to penicillin, clindamycin and metronidazole. Sev enty-nine pleural fluid specimens were obtained from 75 adult patients with empyema. Anaerobic isolates were identified by Crystal anaerobes identific ation system and routine methods. Susceptibility testing was conducted usin g broth microdilution method and limited agar dilution test. Anaerobic bact eria were found in 50 (66.7%) of the patients and included 96 isolates repr esenting 16 genera. The predominant Grampositive anaerobes were Peptostrept ococcus species (19 isolates) and Streptococcus intermedius (10), and the c ommonest Gram-negative species were Fusobacterium nuleatum (13), Fusobacter ium necrophorum (6) and Prevotella inermedia (3). From two to four anaerobe s per specimen were present in 57.4% of the specimens yielding anaerobic ba cteria. The susceptibility of the Gram-negative anaerobic isolates to penic illin and that of the Gram-positive anaerobes to clindamyin and metronidazo le were unpredictable. The variable resistance patterns among anaerobes and the predominance of mixed anaerobic infections highlight the role of the a naerobic dignostics in case of serious pleuropulmonary diseases. (C) 2000 A cademic Press.