Prior antibiotic therapy | Overall | Percentage performed | Chi-square P value | ||
---|---|---|---|---|---|
No | Yes | ||||
Pathogens (%) | 0.002 | ||||
None | 27.5 | 51.8 | 52.5 | ||
Monomicrobial | 33.3 | 29.0 | 29.9 | ||
Polymicrobial | 39.2 | 19.2 | 23.8 | ||
Yield of microbial investigations (%) | |||||
Tracheal aspirate | 87.5 | 79.5 | 81.4 | 81.6 | |
Protected specimen brush | 96.3 | 67.9 | 80.0 | 32.8 | |
Bronchoalveolar lavage | 100 | 71.4 | 77.5 | 4.1 | |
Pathogens identified (all patients) | |||||
Monomicrobial | 17 | 56 | 73 | 0.02 | |
Pseudomonas aeruginosa | 1 | 13 | 14 | ||
Other Pseudomonas | 0 | 2 | 2 | ||
Acinetobacter baumannii | 0 | 11 | 11 | ||
Other Acinetobacter | 0 | 1 | 1 | ||
Enterobacteriaceae | 3 | 12 | 15 | ||
Staphylococcus aureus | 4 | 9 | 13 | ||
Haemophylus influenzae | 6 | 5 | 11 | ||
Streptococcus pneumoniae | 2 | 2 | 4 | ||
Streptococcus viridans group | 0 | 0 | 0 | ||
Other | 1 | 1 | 2 | ||
Polymicrobial | 20 | 38 | 58 | <0.001 | |
Mixed, including NFGNB and methicillin-resistant S. aureus | 4 | 23 | 27 | ||
H. influenzae plus Streptococcus spp. | 9 | 2 | 11 | ||
Other | 7 | 13 | 20 | ||
Pathogens identified (Group Va) | |||||
Monomicrobial | 1 | 7 | 8 | ||
P. aeruginosa | 1 | 2 | 3 | ||
Other NFGNB | 0 | 2 | 2 | ||
Enterobacteriaceae | 0 | 1 | 1 | ||
Methicillin-resistant S. aureus | 0 | 1 | 1 | ||
Other | 0 | 1 | 1 | ||
Polymicrobial | 4 | 11 | 15 | ||
Mixed, including NFGNB and methicillin-resistant S. aureus | 1 | 8 | 9 | ||
Other | 3 | 3 | 6 |