Question 7

What were the predominant pathogens identified in the study as causing the exacerbation?

The predominant pathogens identified in this study were similar to those seen in most COPD studies, namely H. influenzae, H. parainfluenzae, M. catarrhalis and S. pneumoniae. Some Gram negatives including Enterobacterspp., Klebsiella pneumoniae and Pseudomonas spp. were seen (Table 2) (7).

Table 2. Microbiological eradicationa rates at the post-therapy visit in microbiologically evaluable population

		Uncomplicated group			Complicated group
		Levofloxacin	Azithromycin	95% CIb	Levofloxacin	Amoxicillin/ clavulanate	95% CIb
Pathogen category
	Gram-positive aerobic pathogens	20/22 (90.9)	12/15 (80.0)	-37.8-16.0	21/24 (87.5)	14/19 (73.7)	-40.3-12.6
	Gram-negative aerobic pathogens	76/81 (93.8)	88/105 (83.8)	-19.4-0.6	75/93 (80.6)	88/106 (83.0)	-8.9-13.7
Total by pathogen		96/103 (93.2)	100/120 (83.3)	-18.6-1.1	96/117 (82.1)	102/125 (81.6)	-10.6-9.7
Total by patientc		75/80 (93.8)	72/87 (82.8)	-21.2-0.8	70/86 (81.4)	71/89 (79.8)	-13.9-10.7
Pathogen
	Enterobacter cloacae	1/1 (100.0)	3/5 (60.0)		0/0 (0.0)	0/0 (0.0)
	Haemophilius influenzae	26/27 (96.3)	21/24 (87.5)	-25.9-8.3	25/30d (83.3)	20/20 (100.0)	0.8-32.5
	Haemophilius parainfluenzae	18/20 (90.0)	20/23 (87.0)	-24.6-18.5	18/20 (90.0)	15/18 (83.3)	-31.1-17.8
	Klebsiella pneumoniae	2/2 (100.0)	5/6 (83.3)		1/2 (50.0)	4/5 (80.0)
	Moraxella catarrhalis	14/14 (100.0)	18/20 (90.0)	-26.7-6.7	10/12 (83.3)	16/19 (84.2)	-30.0-17.8
	Pseudomonas aeruginosa	3/3 (100.0)	4/6 (66.7)		3/5 (60.0)	4/5 (80.0)
	Staphylococcus aureus	7/7 (100.0)	0/2 (0.0)		4/5 (80.0)	3/5 (60.0)
	Streptococcus pneumoniae	11/12 (91.7)	10/11 (90.9)	-28.4-26.9	16/18 (88.9)	10/13 (76.9)	-42.9-19.0
Data are presented as n/N patients, unless otherwise stated. a  Eradication plus presumed eradication. b  Two-sided 95% CI around the difference of comparator minus levofloxacin. c  Eradication of all pathogens identified at study entry for a patient. d  One patient was inappropriately assessed as a failure by the investigator, even though all of the patient’s baseline symptoms were resolved and H. influenzae had been eradicated. Abbreviation: CI = confidence interval. Adapted from reference (7).