The antibiotic of choice for the treatment of Streptococcus pneumoniae infection is:

Penicillin is considered the antibiotic of choice for treating infections caused by Streptococcus pneumoniae due to its effectiveness against this gram-positive bacterium. Streptococcus pneumoniae is known for causing various infections, including pneumonia, meningitis, and otitis media.

Penicillin works by inhibiting the bacterial cell wall synthesis, leading to cell lysis and death of the bacteria. This mechanism is particularly effective against actively dividing bacteria, such as Streptococcus pneumoniae.

In cases where the strain of Streptococcus pneumoniae is penicillin-resistant, health care providers may consider alternatives such as amoxicillin-clavulanate or other beta-lactams that have a broader spectrum of activity. However, in general, penicillin remains the first-line treatment and is well-tolerated by most patients.

The other options, while they may have their own applications, do not stand as the first choice when it comes to treating infections specifically caused by Streptococcus pneumoniae. For instance, dicloxacillin is more suitable for infections caused by Staphylococcus bacteria, erythromycin is not the preferred treatment for this organism as it may not be effective against penicillin-resistant strains, and although amoxicillin-clavulanate might be considered in