Final answer:
The likely causative agent of pneumonia in a patient who skinned a rabbit is Francisella tularensis, which causes tularemia. The correct option is 4.
Step-by-step explanation:
The most likely pneumonia-causing organism in a patient who just skinned a rabbit is Francisella tularensis, which causes a zoonotic infection known as tularemia or rabbit fever. This gram-negative bacterium is highly infectious and is transmitted through handling of infected animal tissues like those of a rabbit.
Pulmonary infections due to F. tularensis can have a 30%-60% fatality rate if untreated, highlighting the importance of distinguishing it from other pneumonia-causing organisms such as Streptococcus pneumoniae, Klebsiella pneumoniae, or Legionella pneumophila.