Gram-negative bacteria Moraxella

The major precipitants of exacerbations of COPD are acute airways infections. The role of bacteria in precipitating exacerbations is controversial. Bacteria may have a primary role in the development of an exacerbation or represent a secondary superinfection of an initial viral process. The major bacterial organisms that have been associated with exacerbations are Haemophilus influenzae. Streptococcus pneumoniae, and Moraxella (Branhamella) catarrhalis. Mycoplasma pneumoniae and Chlamydia pneumoniae may play a part. In COPD patients with a FEVi < 35% predicted gram-negative bacteria, especially Enterobacteriaceae and Pseudomonas spp. play an important part in acute exacerbations. 

In healthy individuals URT flora multiplies in gastric aspirate during treatment with antisecretory compounds and in particular proton pump inhibitors [34, 40, 44], This concerns viridans streptococci, coagulase-negative staphylococci, Haemophilus sp., diphtheroids, Moraxella sp., lactobacilli, and other streptococci, most of which are Gram-positive bacteria. With dedicated measures anaerobic species of oral origin are also recovered [66]. 

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