Dog or cat exposure Bartonella sp Pasteurella sp Capnocytophaga sp Contact with contaminated milk or infected farm animals Brucella sp Coxiella burnetii Erysipelothrix sp Homeless, body lice Bartonella sp AIDS Salmonella sp S pneumoniae S aureus Pneumonia, meningitis S pneumoniae Solid organ transplantation S aureus Aspergillus fumigatus Enterococcus sp Candida sp Gastrointestinal lesions S gallolyticus (bovis) Enterococcus sp Clostridium septicum HACEK indicates Haemophilus species, Aggregatibacter species, Cardiobacterium hominis, Eikenella corrodens, and Kingella species; IDU, injection drug use; and VGS, viridans group streptococci. Table 6. Epidemiological Clues That May be Helpful in Defining the Etiological Diagnosis of Culture-Negative Endocarditis Epidemiological Feature Common Microorganism IDU S aureus, including community-acquired oxacillin-resistant strains Coagulase-negative staphylococci -Hemolytic streptococci Fungi Aerobic Gram-negative bacilli, including Pseudomonas aeruginosa Polymicrobial Indwelling cardiovascular medical devices S aureus Coagulase-negative staphylococci Fungi Aerobic Gram-negative bacilli Corynebacterium sp Genitourinary disorders, infection, and manipulation, including pregnancy, delivery, and abortion Enterococcus sp Group B streptococci (S agalactiae) Listeria monocytogenes Aerobic Gram-negative bacilli Neisseria gonorrhoeae Chronic skin disorders, including recurrent infections S aureus -Hemolytic streptococci Poor dental health, dental procedures VGS Nutritionally variant streptococci Abiotrophia defectiva Granulicatella sp Gemella sp HACEK organisms Alcoholism, cirrhosis Bartonella sp Aeromonas sp Listeria sp S pneumoniae -Hemolytic streptococci Burn S aureus Aerobic Gram-negative bacilli, including P aeruginosa Fungi Diabetes mellitus S aureus -Hemolytic streptococci S pneumoniae Early ( 1 y) prosthetic valve placement Coagulase-negative staphylococci S aureus Aerobic Gram-negative bacilli Fungi Corynebacterium sp Legionella sp Late (>1 y) prosthetic valve placement Coagulase-negative staphylococci S aureus Viridans group streptococci Enterococcus species Fungi Corynebacterium sp (Continued) Table 6. Continued Epidemiological Feature Common Microorganism Overview of VGS, Streptococcus gallolyticus (Formerly Known as Streptococcus bovis), Abiotrophia defectiva, and Granulicatella Species VGS are common pathogenic agents in community-acquired NVE in patients who are not IDUs. The taxonomy of VGS is evolving. 