Vancomycin is primarily used against which type of bacteria?

• A. Gram-negative bacteria
• B. Gram-positive bacteria
• C. Viruses
• D. Fungi

Answer: (B)

Vancomycin is primarily effective against Gram-positive bacteria. This antibiotic works by inhibiting the synthesis of the bacterial cell wall, which is particularly crucial for Gram-positive organisms that rely on a thick peptidoglycan layer for structural integrity. It is commonly used to treat infections caused by resistant strains of Staphylococcus aureus, including Methicillin-resistant Staphylococcus aureus (MRSA), and other Gram-positive pathogens.

In contrast, Gram-negative bacteria possess a different cell wall structure that vancomycin cannot penetrate effectively, making it ineffective for treating infections from these organisms. Additionally, vancomycin has no activity against viruses and fungi, which have entirely different structures and mechanisms of infection. This specificity for Gram-positive bacteria is a key characteristic that dictates the clinical application of vancomycin in treating various infections.