Which term describes an antimicrobial that kills bacteria directly?

Which term describes an antimicrobial that kills bacteria directly?

• A. Bacteriostatic
• B. Bactericidal
• C. Kirby-Bauer Test
• D. Minimum Inhibitory Concentration (MIC)

Answer: (B)

An antimicrobial that kills bacteria directly is described as bactericidal. Bactericidal agents directly reduce the number of living bacteria, often by damaging the cell wall or membrane or disrupting essential processes to the point of death. In contrast, bacteriostatic agents halt growth or replication, leaving bacteria alive but not dividing, so the infection is cleared by the immune system. The Kirby-Bauer disk diffusion test is a method to assess how susceptible a bacterium is to an antibiotic by measuring zones of no growth around a disk; it doesn’t define whether the drug kills or only inhibits growth. The MIC, or minimum inhibitory concentration, is the smallest concentration that prevents visible growth, which doesn’t necessarily mean the bacteria are killed. If a drug’s killing power is being evaluated, the related concept is the minimum bactericidal concentration.

An antimicrobial that kills bacteria directly is described as bactericidal. Bactericidal agents directly reduce the number of living bacteria, often by damaging the cell wall or membrane or disrupting essential processes to the point of death. In contrast, bacteriostatic agents halt growth or replication, leaving bacteria alive but not dividing, so the infection is cleared by the immune system.

The Kirby-Bauer disk diffusion test is a method to assess how susceptible a bacterium is to an antibiotic by measuring zones of no growth around a disk; it doesn’t define whether the drug kills or only inhibits growth. The MIC, or minimum inhibitory concentration, is the smallest concentration that prevents visible growth, which doesn’t necessarily mean the bacteria are killed. If a drug’s killing power is being evaluated, the related concept is the minimum bactericidal concentration.