Antibiotic improve treatment outcome as the combined effect of both antibiotics is better than their individual effect. Methicillin-resistant Staphylococcus aureus infections may be treated with a combination therapy of fusidic acid and rifampicin. Antibiotics used in combination may also be antagonistic and the combined effects of the two antibiotics may be less than if the individual antibiotic was given as part of a monotherapy. For example, chloramphenicol and tetracyclines are antagonists to penicillins and aminoglycosides. However, this can vary depending on the species of bacteria. In general, combinations of a bacteriostatic antibiotic and bactericidal antibiotic are antagonistic. Antibiotics are commonly classified
Antibiotic use in livestock antibiotic given to the livestock. Since the primary study, there have been many well-documented events showing that antibiotic usage in livestock results in direct influence of antibiotic resistance in humans. Major bacterial infections in humans can be traced back to livestock. The family Enterobacteriaceae includes many opportunistic bacteria, including "E. coli", which are commonly found in livestock. Other bacteria include "Klebsiella" and "Staphylococcus aureus". They cause infections in the urinary tract, digestive system, skin, and bloodstream, and account for a significant portion of antibiotic-resistant bacterial infections. The practice of using antibiotics for growth stimulation is problematic for these reasons: Donald