What are the 4 main ways bacteria are resistant to antibiotics (mechanisms of resistance)?

1) penicillinases-destruction or inactivation of drug ex: penecillin includes beta lactam ring that cleaves to penicillinases and results to resistance to penicillin2) erythromycin resistance-prevention of penetration to target site (reducing uptake)-gram - are more resistant to antibiotics b/c of lack of peptidoglycan-ex: penicillin cant enter due to penicillinases-making inactivation by enzymes easier3) mrsa-alteration of target site-involved movement of a ribosome along a strand of mrna ex: mrsa modifies pbp on the cells membrane, allows mrsa strains to survive despite antibiotics4) tetracycline resistance-rapid efflux (ejection) of the antibiotic ex: certain proteins in plasma membrane of gram - bacteria act as pumps that expel antibiotics, preventing them from reaching an effective concentration