Which of the following is a characteristic of Staphylococcus aureus?

Staphylococcus aureus is characterized as a facultative anaerobe, meaning it can grow in both the presence and absence of oxygen. This flexibility allows it to thrive in various environments, including human skin and mucous membranes, where oxygen levels may vary. This adaptability plays a significant role in its ability to cause foodborne illnesses when it enters food due to contamination, as it can proliferate even in low-oxygen conditions.

The other options do not accurately describe Staphylococcus aureus. It is not an obligate intracellular organism, which would require living host cells for growth. Additionally, it does not form spores, as true spore formers are typically associated with genera like Bacillus or Clostridium. Lastly, "sporadic" refers to a pattern of occurrence rather than a biological characteristic of an organism, making it irrelevant in this context. Thus, the correct identification as facultative anaerobic highlights the organism's growth capabilities and its significance in food safety.