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 prophylaxis 2006 against antibiotics for growth promotion purposes. It was estimated in 2014 that over 80% of the world's antibiotic use was on farms. Coccidiosis in fowl had evolved increased tolerance to the antibiotic feed. The WHO warned in April 2014 that farm use was a contributor to superbugs in humans. The Auditor General of Canada found lack of progress in 2014 on antimicrobial resistance despite three years of government funds that should have been used to implement a reduction programme. A CBC writer was concerned that there was in Canada "no coordinated national system to control antibiotics in agriculture." Due