Cryptogenic Liver Abscess Caused by a K1 Serotype Isolate.

Hypervirulent (hv) is a common cause of pyogenic liver abscesses in Asia but is quite uncommon in North America. Among the cases described in North America, only occasional reports have described molecular strain typing to confirm the K1 strain as the causative agent. We report a 56-year-old Hispanic female with no previous intra-abdominal pathology and no recent travel, who presented with subacute abdominal pain and developed bacteremia and monomicrobial pyogenic liver abscess due to a community-acquired K1 serotype isolate. In this case, the infection was recognized early, so the patient was successfully treated with percutaneous drainage and prolonged antibiotic therapy. Hv can cause severe invasive disease with high morbidity and mortality, and the recent emergence of multidrug resistance in these strains poses a serious threat to public health. In addition, the isolation of a K1 strain from a cryptogenic liver abscess in a Hispanic patient with no epidemiologic risk factors raises concern for a wider spread of the hypervirulent strain beyond Asian populations. Therefore, a high index of suspicion for hv infection in the Hispanic population can be crucial as the hypervirulent strain is likely to cause severe metastatic infection with significant morbidity and mortality.