Final answer:
The respiratory therapist should suspect Pseudomonas aeruginosa as the causative agent of pneumonia in an intubated patient with offensive, green, mucopurulent sputum.
Step-by-step explanation:
When a sputum sample from an intubated patient with pneumonia has an offensive odor and is described as green and mucopurulent, the respiratory therapist should suspect Pseudomonas aeruginosa as the causative pathogen.
Pseudomonas aeruginosa is a gram-negative rod, opportunistic in nature, known for causing ventilator-associated pneumonia, especially in patients with conditions like cystic fibrosis or those who are hospitalized and assisted with artificial ventilators.
Given the fact that the patient in question is intubated and the sputum cultures revealed the presence of a gram-negative rod, along with the traits of the sputum such as its offensive odor and color, these are indicative of an infection by Pseudomonas aeruginosa.