Bottom line
Entamoeba histolytica is the most common cause of liver abscess worldwide, but identifying risk factors and mechanism of infection can lead to the most likely infecting organism.
Dr. Mehra is assistant professor of medicine in the Section of Hospital Medicine at the University of Virginia Medical Center and School of Medicine, Charlottesville. Dr. Parsons is also assistant professor of medicine in the Section of Hospital Medicine at the University of Virginia Medical Center and School of Medicine.
References
Chemaly RF. Microbiology of liver abscesses and the predictive value of abscess gram stain and associated blood cultures. Diagn Microbiol Infect Dis. 2003;46(4):245-8.