Blackwells Underground Clinical Vignettes: Microbiology, Volume I, third edition is your primary source for clinically relevant, case-based material essential for Step 1 review. Each Clinical Vignette presents approximately 100 cases with over 1000 classic buzzwords in Hx, PE, lab, imaging, pathology and treatment. 
The revised editions contain: · High-yield updates to nearly every case 
 · Links to Basic Science and Clinical Science Color Atlas
 · New Cases on commonly tested USMLE topics
ID/CC-A 25-year-old IV drug abuser presents with a high fever with chills, malaise, a productive cough, hemoptysis, and right-sided pleuritic chest pain. 
HPI-He also reports multiple skin infections at injection sites. 
PE-VS: fever. PE: stigmata of intravenous drug abuse at multiple injection sites; skin infections; thrombosed peripheral veins; splenomegaly and pulsatile hepatomegaly; ejection systolic murmur, increasing with inspiration, heard in tricuspid area. 
Labs-CBC: normochromic, normocytic anemia. UA: microscopic hematuria. Blood culture yields Staphylococcus aureus. 
Imaging-Echo: presence of vegetations on tricuspid valve and tricuspid incompetence. CXR: consolidation. 
Gross Pathology-N/A 
Micro Pathology-N/A 
Treatment-High-dose intravenous penicillinase-resistant penicillin in combination with an aminoglycoside. If the isolated S. aureus strain is methicillin resistant, vancomycin is the drug of choice. 
Discussion-In drug addicts, the tricuspid valve is the site of infection more frequently (55%) than the aortic valve (35%) or the mitral valve (30%); these findings contrast markedly with the rarity of right-sided involvement in cases of infective endocarditis that are not associated with drug abuse. Staphylococcus aureus is responsible for the majority of cases. Certain organisms have a predilection for particular valves in cases of addict-associated endocarditis; for example, enterococci, other streptococcal species, and non-albicans Candida organisms predominantly affect the valves of the left side of the heart, while S. aureus infects valves on both the right and the left side of the heart. Pseudomonas organisms are associated with biventricular and multiple-valve infection in addicts. Complications of endocarditis include congestive heart failure, ruptured valve cusp, myocardial infarction, and myocardial abscess.