Which organism is commonly associated with inpatient cellulitis?

Inpatient cellulitis is often associated with both Gram-negative organisms and Staphylococcus aureus, which is why this choice is the correct answer.

Staphylococcus aureus, particularly methicillin-resistant Staphylococcus aureus (MRSA), frequently contributes to skin and soft tissue infections, including cellulitis, especially in hospital settings where patients may have exposure to such pathogens. Additionally, Gram-negative organisms can also be implicated, particularly in patients who have risk factors such as diabetes, immunocompromise, or those undergoing invasive procedures. In the hospital environment, the diversity of potential pathogens increases, making the presence of both Gram-negative organisms and S. aureus notable in the context of inpatient cellulitis.

Staphylococcus epidermidis, while a common skin flora and opportunistic pathogen, is less frequently the primary cause of serious cellulitis in patients. Escherichia coli primarily causes infections in specific scenarios, such as urinary tract infections or intra-abdominal infections, rather than as a common cause of cellulitis. Streptococcus pyogenes is an important pathogen for cellulitis, particularly in community settings, but in the context of hospitalized patients, the likelihood of encountering multiple organisms, including more resistant strains like MRSA, is higher. Therefore, option