Table 1.

Abundance and significance of NTHi and other potentially pathogenic bacteria in healthy individuals and various stages of COPD using culture-based methods.

Sample type	Microbiological analysis	Main findings			Study
		Healthy individuals	AECOPDb	Stable COPD disease
PSBa	Quantitative culture	Potentially pathogenic bacteria found in 4% of patients	Potentially pathogenic bacteria found in 54% of patients	Potentially pathogenic bacteria found in 29% of patients	Rosell et al. (148)
		NTHi found in 3% of patients	NTHi found in 30% of patients (predominating species)	NTHi found in 17% of patients (predominating species)
BALc	Quantitative culture	Potentially pathogenic bacteria found in 0% of ex-smokers and in 20% of non-smokers (no NTHi)	N.A.d	Potentially pathogenic bacteria found in 34% of patients	Sethi et al. (216)
				NTHi predominating species
Sputum/Throat swab/PSB /BAL	Culture and molecular typing of strains	NTHi recovered in 35% of patients at any respiratory site	NTHi recovered in 7% of intubated patients with respiratory exacerbation	NTHi recovered in 57% of patients at any respiratory site	Bandi et al (217)
Sputum	Culture and molecular typing of strains	N.A.	Isolation of a new strain of NTHi significantly associated with exacerbation	N.A.	Sethi et al. (153)
			Patients with a new NTHi-strain twice as likely to have AECOPD
Sputum	Quantitative culture	N.A.	Potentially pathogenic bacteria found in 70% of exacerbations	Potentially pathogenic bacteria found in 48% of patients	Wilkinson et al. (172)
			NTHi predominating species (38%)	NTHi predominating species (14%)
Sputum	Quantitative culture	N.A.	Potentially pathogenic bacteria found in 55% of exacerbations	Potentially pathogenic bacteria found in 38% of cultures	Papi et al. (171)
			NTHi predominating species	NTHi predominating species

^aPSB, protected specimen brush.

^bAECOPD, acute exacerbation of COPD.

^cBAL, bronchoalveolar lavage.

^d N.A., not applicable.