Antimicrobial spectrum

Antimicrobial spectrum refers to the range of microorganisms that an antimicrobial agent can effectively inhibit or kill. This spectrum can be broad, targeting a wide variety of organisms, or narrow, targeting a specific group. The antimicrobial spectrum is a critical factor in the selection of antimicrobial therapy.

Overview

The antimicrobial spectrum of a drug is determined by its pharmacodynamics and pharmacokinetics. Pharmacodynamics refers to the drug's effect on the microorganism, while pharmacokinetics refers to the drug's absorption, distribution, metabolism, and excretion in the body.

Broad-spectrum antimicrobials

Broad-spectrum antimicrobials are capable of inhibiting or killing a wide range of microorganisms. They are often used when the specific pathogen is unknown, or when a mixed infection is suspected. Examples of broad-spectrum antimicrobials include tetracyclines, fluoroquinolones, and carbapenems.

Narrow-spectrum antimicrobials

Narrow-spectrum antimicrobials are more selective, targeting specific groups of microorganisms. They are typically used when the pathogen is known, or when it is important to minimize disruption to the normal microbiota. Examples of narrow-spectrum antimicrobials include penicillin G, erythromycin, and vancomycin.

Determining the antimicrobial spectrum

The antimicrobial spectrum of a drug can be determined through susceptibility testing, which involves exposing a microorganism to the drug and observing its response. This can be done in a laboratory setting using techniques such as the disk diffusion test or the broth dilution test.

Clinical implications

Understanding the antimicrobial spectrum is crucial in the clinical setting, as it guides the selection of appropriate therapy. Broad-spectrum antimicrobials may be used empirically, while narrow-spectrum antimicrobials are typically used once the pathogen has been identified. The antimicrobial spectrum also has implications for antimicrobial resistance, as overuse of broad-spectrum antimicrobials can contribute to the development of resistance.

See also

• Antimicrobial resistance
• Pharmacodynamics
• Pharmacokinetics
• Broad-spectrum antimicrobials
• Narrow-spectrum antimicrobials