Pharma-Ecology, 2nd Edition

3Usage of Antimicrobial Agents and Related Endpoints

LEARNING OBJECTIVES

1. What are antimicrobials and how they work (i.e. modes of action).
2. Impact of socioeconomic, physician practices, and healthcare systems in antimicrobial consumption.
3. Importance of livestock and other agricultural practices in antimicrobial consumption.
4. Antimicrobial resistance traits and implications to environmental health.

Antimicrobial compounds generally include antibiotics, antifungal agents, antiprotozoal agents, and antiviral agents. Antibiotics stop microorganisms, primarily bacteria and fungi, from growing (i.e. bacteriostatic) or kill these organisms outright (i.e. bactericidal). Some antibiotics have both bacteriostatic and bactericidal effects. Most antibacterial agents are ineffective against fungi, and similarly, most antifungal agents are not effective against bacteria. Most classes of antibiotic are from natural products although individual antibiotics currently on the market are semisynthetic as they were greatly modified or engineered to incorporate desirable traits. Such desirable traits introduced through engineering include enhanced oral bioavailability, a wider range of active targets, increased stability, and increased efficacy against target microorganisms.

The annual global usage of antibiotics is not precisely known. Production in the United States is estimated at more than 22.7 million kilograms of antibiotics with more than 40% used as animal feed supplements (Kumar et ...