Bacteriology and Comorbidities in Patients Requiring Surgical Management of Empyema

Concern over the changing bacteriology of empyema has led to numerous attempts to characterize the most common locoregional bacterial isolates. The purpose of this study is to better characterize the bacteriology and demographics in patients with community-acquired pneumonia (CAP) and hospital-acquired pneumonia requiring surgery for empyema. All patients diagnosed with empyema preoperatively and had either a video-assisted thoracoscopic or open decortication surgery from January 2010 to September 2015 were reviewed. Forty-seven patients were identified with a mean age of 54.7 ± 16.8 years (X ± SD). Sixty per cent of patients had CAP. Anaerobes were the most common isolate at 21 per cent, followed by Streptococcus species and Staphylococcus aureus (50% Methicillin Resistant). Coagulase-negative Staphylococcus species were the next most frequent at 13 per cent. Hospital-acquired pneumonia patients had a higher incidence of S. aureus infections (P = 0.047). Cancer history had higher rates of both fungal (P = 0.004) and gram-negative infections (P = 0.03). Older patients had increased incidence of gram-negative infections (P = 0.05). The median length of stay for CAP patient who were intravenous drug abusers (n = 3) were 31 days (95% confidence interval (CI) [15, NA]), which was significantly longer than the others (median 12 days, 95% CI: [9, 18], P = 0.014). Streptococcus pneumoniae was not found in any of the isolates. Our data reveal that anaerobes and Staphylococcus species have replaced S. pneumoniae as the major regional pathogens in surgically treated empyema. In addition, anaerobic isolates were found in higher incidence in CAP than previously reported.