Which microbe is Penicillin primarily indicated for?

Penicillin is primarily indicated for the treatment of infections caused by certain types of bacteria, particularly those that are sensitive to this antibiotic. Streptococcus species, including Streptococcus pneumoniae, and Haemophilus influenzae are well-known for their susceptibility to penicillin. This effectiveness is attributed to the structure of penicillin, which interferes with bacterial cell wall synthesis, ultimately leading to cell lysis and death in these types of bacteria.

Streptococcus can cause a variety of infections, including streptococcal pharyngitis (strep throat), pneumonia, and skin infections. Similarly, Haemophilus influenzae can lead to conditions such as pneumonia and meningitis. The effectiveness of penicillin against these microbes makes it a first-line treatment option for infections associated with them, emphasizing why this choice is the correct one.

In contrast, other bacteria listed in the other choices present different challenges. For example, Staphylococcus aureus, particularly the methicillin-resistant strain (MRSA), is generally resistant to penicillin. Likewise, Escherichia coli and Klebsiella species may also exhibit resistance, necessitating other classes of antibiotics. Pseudomonas and Mycoplasma are usually not susceptible to pen