title: The bacteriology of pleural infection by genetic and standard methods and its mortality significance.
abstract: BACKGROUND
  Antibiotic choices for pleural infection are uncertain as its bacteriology is poorly described.
  
  
  METHODS
  Pleural fluid from 434 pleural infections underwent standard culture and a screen for bacteria by amplification and sequencing of bacterial 16S ribosomal RNA gene.
  
  
  RESULTS
  Approximately 50% of community-acquired infections were streptococcal, and 20% included anaerobic bacteria. Approximately 60% of hospital-acquired infections included bacteria frequently resistant to antibiotics (methicillin-resistant Staphylococcus aureus, 25%; Enterobacteriaceae, 18%; Pseudomonas spp., 5%, enterococci, 12%). Mortality was increased in hospital-acquired infection (hospital, 17/36 [47%]; community, 53/304 [17%]; relative risk, 4.24; 95% confidence interval, 2.07-8.69; p < 0.00001; chi(2), 1 df = 17.47) and in gram-negative (10/22 [45%]), S. aureus (15/34 [44%]), or mixed aerobic infections (13/28 [46%]), compared with streptococcal infection (23/137 [17%]) and infection including anaerobic bacteria (10/49 [20%]; p < 0.00001, chi(2), 4 df = 23.35).
  
  
  CONCLUSIONS
  Pleural infection differs bacteriologically from pneumonia and requires different treatment. Antibiotics for community-acquired infection should treat aerobic and anaerobic bacteria. Hospital-acquired, gram-negative S. aureus and mixed aerobic infections have a high mortality rate.
authors.affiliation: Department of Respiratory Medicine, Southmead Hospital, North Bristol NHS Trust, UK.
authors.forename: Nick A
authors.initials: NA
authors.lastname: Maskell
authors.forename: Sarah
authors.initials: S
authors.lastname: Batt
authors.forename: Emma L
authors.initials: EL
authors.lastname: Hedley
authors.forename: Christopher W H
authors.initials: CW
authors.lastname: Davies
authors.forename: Stephen H
authors.initials: SH
authors.lastname: Gillespie
authors.forename: Robert J O
authors.initials: RJ
authors.lastname: Davies
mesh_terms: D000328:Adult; D000368:Aged; D001424:Bacterial Infections / Q000188:drug therapy* / Q000382:microbiology* / Q000401:mortality; D017714:Community-Acquired Infections / Q000188:drug therapy / Q000235:genetics / Q000401:mortality; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010996:Pleural Effusion / Q000188:drug therapy / Q000382:microbiology* / Q000401:mortality; D011014:Pneumonia / Q000382:microbiology; D016133:Polymerase Chain Reaction; D011379:Prognosis; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013203:Staphylococcal Infections / Q000188:drug therapy; D013290:Streptococcal Infections / Q000188:drug therapy; D016019:Survival Analysis
chemical_list: D012336:RNA, Ribosomal, 16S