Clinical and Molecular Evidence of Atovaquone and Azithromycin Resistance in Relapsed Babesia microti Infection Associated With Rituximab and Chronic Lymphocytic Leukemia

Babesiosis treatment failures with standard therapy have been reported, but the molecular mechanisms are not well understood. We describe the emergence of atovaquone and azithromycin resistance associated with mutations in the binding regions of the target proteins of both drugs during treatment of an immunosuppressed patient with relapsing babesiosis.