Table 4.

Microbiologic documentation available in visit 2 in modified intention-to-treat patients with nosocomial pneumonia

	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

NFGNB, nonfermenting Gram-negative bacilli. Overall, there were 33 Pseudomonas isolates, including 30 Pseudomonas aeruginosa, two Pseudomonas putida, and one Pseudomonas spp., and 22 Acinetobacter isolates, including 20 A. baumannii, one Acinetobacter haemolyticus, and one Acinetobacter calcoaceticus. ^aGroup V, patients who initially received inadequate antibiotic therapy, which was later modified on the basis of cultures.