Early Clinical Response of a Large Amebic Liver Abscess to Eravacycline Prior to Metronidazole Initiation: A Case Report.

Entamoeba histolytica is an amebic protozoan that is often asymptomatic, with many patients being asymptomatic carriers. However, 10 percent of cases manifest with amebic dysentery and, less commonly, amebic liver abscesses. Amebic liver abscesses are the most common extraintestinal manifestation of E. histolytica. Patients may remain asymptomatic for years before presenting with active infection. Treatment of E. histolytica amebic abscesses with nitroimidazoles, such as metronidazole and tinidazole, is a long-established approach that has remained unchanged since its discovery in the 1960s. However, given that this condition is known to be fatal without treatment, the outcome for a patient who cannot tolerate nitroimidazole therapy can be catastrophic. We present the case of a 54-year-old male who presented with what was initially thought to be a large, pyogenic liver abscess and who was started on standard empiric antibiotic therapy and percutaneous drainage. However, due to a lack of clinical response, his regimen was changed to eravacycline, a novel halogenated tetracycline, which led to a good response. Interestingly, the abscess was later discovered to be amebic in this patient, who had a low-risk history for E. histolytica infection. This case demonstrates a clinical response to eravacycline monotherapy in a patient with E. histolytica liver abscess. We re-examine the history of tetracyclines in the treatment of parasitic infections and consider the new, more potent halogenated tetracyclines as a potential alternative to the current standard of care.