A 73-year-old veteran who has smoked 1-2 packs of cigarettes per day since he was 16 years old is seen at the emergency room with a nonproductive cough, fever, and diarrhea for 2 days. The organism did not take up the Gram stain or the acid fast stain (i. e. unstained following each process). A silver stain did demonstrate coccobacilli. The bacterium responsible for this disease requires cysteine for growth in culture. Which one of the is most likely the causative agent for this clinical presentation