Aggregatibacter aphrophilus pyogenic liver abscess in an immunocompetent young woman

Aggregatibacter aphrophilus (formerly Haemophilus aphrophilus/paraphrophilus) is a small Gram-negative coccobacillus with fastidious growth requirements. It is a normal commensal of the human oropharynx and upper respiratory tract, and it can infrequently cause invasive human diseases, including bone and joint infections and subacute infective endocarditis. Cases of liver abscess caused by Aggregatibacter aphrophilus have been sparsely recorded in the English-language literature, but have not yet been reported in Taiwan. Here we present a case of Aggregatibacter aphrophilus pyogenic liver abscess in an immunocompetent young woman. She recovered uneventfully after repeated percutaneous abscess aspiration and antibiotic treatment for 5 weeks.