Antibiotics,a main tool in controlling pathogen infections,by their nature are designed to target and inhibit microorganisms in a variety of ways.The majority of clinical antibiotics have a broad spectrum of activity;hence,in addition to killing the pathogenic bacteria they can also potentially inflict collateral damage on commensal bacteria in gut and metabolism.In recent years,antibiotics abuse has been increased notably and dawn greater attention,especially macrolides,sulfonamides and tetracyclines.