Final answer:
Pseudomonas aeruginosa is an obligate aerobe often associated with opportunistic infections, especially in patients with cystic fibrosis, and is known for its ability to form biofilms and produce green pigment pyocyanin.
Step-by-step explanation:
Pseudomonas aeruginosa is a gram-negative, oxidase-positive, aerobic bacillus that is capable of causing various opportunistic infections, particularly in individuals with compromised immune systems. Notably, it infects the airways of patients with cystic fibrosis and does not grow in the absence of oxygen, categorically defining it as an obligate aerobe. Pseudomonas aeruginosa is also a frequent cause of infections associated with burns, wounds, and can be associated with nosocomial infections transmitted via medical devices.
This organism is known for creating biofilms, which can contribute to its persistence in hospital environments and resistance to antibiotics. As demonstrated in figure 7.25 (b), it can produce a green pigment known as pyocyanin, which is observable when the bacterium is grown on cetrimide agar.