Broad-spectrum antibiotic focusing on evidence-based approaches to minimize resistance. In humans: In veterinary medicine, co-amoxiclav, (in small animals); penicillin & streptomycin and oxytetracycline (in farm animals); penicillin and potentiated sulfonamides (in horses). Broad-spectrum antibiotic The term broad-spectrum antibiotic can refer to an antibiotic that acts on the two major bacterial groups, gram-positive and gram-negative, or any antibiotic that acts against a wide range of disease-causing bacteria. These medications are used when a bacterial infection is suspected but the group of bacteria is unknown (also called empiric therapy) or when infection with multiple groups of bacteria is suspected. This is in contrast to
Antibiotic phenomenon exhibited by these early antibacterial drugs. Antibiosis was first described in 1877 in bacteria when Louis Pasteur and Robert Koch observed that an airborne bacillus could inhibit the growth of "Bacillus anthracis". These drugs were later renamed antibiotics by Selman Waksman, an American microbiologist, in 1942. The term "antibiotic" was first used in 1942 by Selman Waksman and his collaborators in journal articles to describe any substance produced by a microorganism that is antagonistic to the growth of other microorganisms in high dilution. This definition excluded substances that kill bacteria but that are not produced by microorganisms (such as