Clinical and bacterial characteristics in Danish adults with pleural empyema Karin Armbruster, Christian Niels Meyer, Michael Kemp, Trine Rolighed Thomsen, Alice Friis-Moeller, Ram Benny Dessau Gentofte University Hospital, Roskilde Hospital, Odense University Hospital, Aalborg University, Hvidovre University Hospital, Slagelse Hospital Introduction Recent studies have focused on the changes in bacterial etiology and the consequences for treatment of pleural infection. Our aim was to supplement the microbiological data with further identification of species using molecular methods and with further information on clinical and therapeutic factors and risk factors in patients with pleural infection. Methods Cases were identified prospectively in the clinical practice and by combining ICD-diagnosis DJ and results of microbiology from the laboratory information systems. Clinical and microbiology data are presented of the first 157 patients (out of 425 cases) with pleural infection, collected pro- and retrospectively from 8 Danish hospitals ( ). In a subgroup of cases, frozen samples were collected prospectively for further direct identification by molecular methods: cloning, standard 16S rRNA PCR, and three group specific primer pairs (for identifying mixed infection) with RipSeq analysis of the PCR product 1. Among the106 culture positive cases, a simultaneous dry transportation (in tubes) and liquid medium transportation (blood culture bottles) was performed in 16 cases, of which 15 were culture positive by both methods and one was culture positive in blood culture bottles only. Bacterial DNA was identified in 26 (of 73 samples analyzed, Table 3) samples of which 15 were also culture positive. Particularly anaerobic bacteria (Fusobacterium species, especially) were frequent among PCR/RipSeq identified bacterial species (n= 24), which were not identified by traditional culture. Conclusions Treatment and outcome data, combined with microbiological and clinical characteristic among patients with pleural infection are described, and new data on microbiological identification using molecular methods are presented; which identified additional micro-organisms compared to traditional culture methods. Cancer (Pulmonary cancer) n = 31 (n=12, 39%) 28,1% Alcohol abusen = 2724,5% Diabetes mellitusn = 1311,8% COPDn = 1110 % General weaknessn = 10 9,1% Other (neurological and psyciatric disease etc.) n = 1816,5 % Results Among the 157 cases, males accounted for 66% and females 34%, with a similar age range: median of 64 years (range 22-97, IQR 54-73). Mortality was 10% and the median time from date of admission to death was 24 days (range 2-89). Risk factors were present in 64% of cases (n=110, table 1). In the previous 2 months, 7% (n=11) had a history of thoracic trauma, 3,2% (n= 5) had a history of thoracic intervention, and 5,7% (n=9) had simple pleurocentesis performed. Treatment included intra-pleural fibrinolysis in 35% of cases, and 11,6% were referred for thoracic surgery (subgroup mortality 5,6%). The length of in-hopital stay was median 16 days (range 1-73) Community acquired infections accounted for 82% of cases. Table1. Risk-factors in patients with pleural infection Table 2. Microbiological findings by standard culture methods Culture and PCR-analysis positive PCR-analysis positive only Culture positive only Culture and PCR-analysis negative 20,5% (n=15) 15,1% (n=11) 4,1% (n=3)60,3% (n=44) Table 3. Bacterial identification by culture vs. triple primer 16S rRNA PCR and sequensing of the product (73 samples) Reference: 1. Kommedal et al.: J Med Microbiol. 2011; 60: 927 – 36 Total Nosocomia l n=106in %n=12in % Streptococcus anginosus/intermediu s Non-hemolytic streptococci Streptococcus pneumoniae Anaerobes109.4 Hemophilus influenzae32.8 Staphylococcus aureus Staphylococcus lugdunensis21.9 Eschericia coli32.8 Pseudomonas aeruginosa Proteus vulgaris Enterobacter species Other bacteriae