Antibiotic synergy with enterococcal endocarditis experienced a high relapse rate when penicillin G alone was used for treatment and a demonstrably lower relapse rate when streptomycin was combined with penicillin G to combat the infection. Since that time the research community has conducted numerous studies regarding the effects and possibilities of antibiotic combinations. Today, combination therapy is recognized as providing a broad spectrum of antibiotic coverage, effectively fighting polymicrobial infections, minimizing selection for antibiotic resistant strains, lowering dose toxicity where applicable, and in some cases providing synergistic activity. Antibiotic synergy is desirable in a clinic sense for several reasons. At the patient
Antibiotic use in livestock in its inaugural 2013 report on antibiotic resistance threats in the United States, the CDC identified resistant non-typhoidal "Salmonella" and "Campylobacter" as "serious threats" and called for improved surveillance and intervention in food production moving forward. There are other bacteria as well, where research is evolving and revealing that bacterial resistance acquired through use in livestock may be contributing to disease in humans. Examples of these include Enterococcus (including "E. coli" 0157) and "Staphylococcus aureus". For foodborne illness from "E. coli", which is still not typically treated with antibiotics because of associated risk of renal failure, increasing rates of antibiotic-resistant