The correct answer is
Azithromycin (choice C).The ATS/IDSA 2019 guidelines recommend administering combination therapy with a β-lactam, such as ceftriaxone, and a macrolide, such as azithromycin, for the treatment of adult inpatients with non-severe community-acquired pneumonia (CAP) and no risk factors for MRSA or
P. aeruginosa . This recommendation is also supported by the ALAT/ERS/ESCMID/ESICM 2023 guidelines, which suggest adding macrolides, not fluoroquinolones, to β-lactams as empirical antibiotic therapy in hospitalized patients with severe CAP
Vancomycin (choice A) is not the correct choice. While vancomycin is used for the treatment of infections caused by methicillin-resistant
Staphylococcus aureus (MRSA), it is not typically added to ceftriaxone for the treatment of community-acquired pneumonia unless MRSA is suspected.
Clarithromycin (choice B) is also a macrolide and could be used in combination with ceftriaxone for the treatment of CAP. However, azithromycin is often preferred due to its simpler dosing regimen and better tolerability
. Therefore, while clarithromycin could be a viable option, azithromycin is the better choice in this case.
In summary, azithromycin is the recommended antibiotic to add to ceftriaxone for the treatment of non-severe community-acquired pneumonia in adult inpatients without risk factors for MRSA or
Pseudomonas aeruginosa, based on current clinical guidelines.