For which type of bacteria should penicillin G be considered?

Penicillin G is primarily effective against Gram-positive cocci, which include bacteria such as Streptococcus and Staphylococcus species. This is because these bacteria typically possess a thick peptidoglycan layer in their cell walls, which is susceptible to the action of penicillin. Penicillin G works by inhibiting the synthesis of this cell wall, leading to cell lysis and death of the bacteria.

The effectiveness of penicillin G on Gram-positive cocci is well-documented, making it a standard choice for treating infections caused by these organisms. It is particularly useful in treating infections such as pneumonia, endocarditis, and certain skin infections where these bacteria are commonly involved.

In contrast, other options like anaerobic bacteria or Gram-negative rods present challenges for penicillin G due to differences in their cell wall structure. Anaerobic bacteria may possess resistance mechanisms, and Gram-negative rods have an outer membrane that prevents penicillin G from effectively reaching the peptidoglycan layer. Ova and parasites are also not affected by antibiotics like penicillin, as they are fundamentally different organisms. Understanding the specific bacterial characteristics helps clarify why penicillin G is particularly suited for Gram-positive cocci.