An antibiotic active against a wide range of gram-positive organisms (see BACTERIA; GRAM'S STAIN), including the STAPHYLOCOCCUS. It is not used for general infections, for which penicillin derivatives are preferred, but reserved for intravenous route in the prophylaxis and treatment of ENDOCARDITIS and other serious infections caused by gram-positive cocci – in particular, METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS (MRSA). Its blood levels must be monitored to make sure it does not reach levels potentially damaging to the middle ear and the kidney. A short course of vancomycin is effective in the treatment of antibiotic-associated COLITIS, for which it is given by mouth.