Some contain photosynthetic pigments

• One of two usually recognized orders of true bacteria
• Gram-negative spiral or spherical or rod-shaped bacteria usually motile by polar flagella

Wikipedia Word definitions in Wikipedia
The Pseudomonadales are an order of Proteobacteria . A few members are opportunistic pathogens, such as species of Pseudomonas , Moraxella , and Acinetobacter , which may cause pneumonia .