<P> The treatment of bacteremia should begin with empiric antibiotic coverage . Any patient presenting with signs or symptoms of bacteremia or a positive blood culture should be started on intravenous antibiotics . The choice of antibiotic is determined by the most likely source of infection and by the characteristic organisms that typically cause that infection . Other important considerations include the patient's past history of antibiotic use, the severity of the presenting symptoms, and any allergies to antibiotics . Empiric antibiotics should be narrowed, preferably to a single antibiotic, once the blood culture returns with a particular bacteria that has been isolated . </P> <P> The Infectious Disease Society of America (IDSA) recommends treating uncomplicated methicillin resistant staph aureus (MRSA) bacteremia with a 14 - day course of intravenous vancomycin . Uncomplicated bacteremia is defined as having positive blood cultures for MRSA, but having no evidence of endocarditis, no implanted prostheses, negative blood cultures after 2--4 days of treatment, and signs of clinical improvement after 72 hrs . </P> <P> The antibiotic treatment of choice for streptococcal and enteroccal infections differs by species . However, it is important to look at the antibiotic resistance pattern for each species from the blood culture to better treat infections caused by resistant organisms . </P> <P> The treatment of gram negative bacteremia is also highly dependent on the causative organism . Empiric antibiotic therapy should be guided by the most likely source of infection and the patient's past exposure to healthcare facilities . In particular, a recent history of exposure to a healthcare setting may necessitate the need for antibiotics with pseudomonas aeruginosa coverage or broader coverage for resistant organisms . Extended generation cephalosporins such as ceftriaxone or beta lactam / beta lactam inhibitor antibiotics such as piperacillin - tazobactam are frequently used for the treatment of gram negative bacteremia . </P>

The colonization of bacteria on the valves of the heart can result in which of the following