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 cover all these areas and instead focuses on the use of antibiotics for growth promotion, which has been banned in Europe since 2006, and on legislation regarding antibiotic use in farm animals in the USA. In 2013, the CDC finalized and released a report detailing antibiotic resistance and classified the top 18 resistant bacterium as either being urgent, serious or concerning threats. Of those organisms, three ("C. diff", carbapanem-resistant enterobacteriaceae, and "Neisseria gonorrhoeae") have been classified as urgent threats and require more monitoring and prevention. In the US alone, more than 2 million people are diagnosed with antibiotic-resistant infections and