The bacteriology of pleural infection by genetic and standard methods and its mortality significance.
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.
Maskell
Nick A
NA
Department of Respiratory Medicine, Southmead Hospital, North Bristol NHS Trust, UK.
Batt
Sarah
S
Hedley
Emma L
EL
Davies
Christopher W H
CW
Gillespie
Stephen H
SH
Davies
Robert J O
RJ
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
D012336:RNA, Ribosomal, 16S