RESUMEN
A 37-year-old male patient presented with a fever, chills, and abdominal pain. The patient was diagnosed with Typhoid fever based on blood culture, but did not clinically respond to standard antibiotic (Ceftriaxone) therapy. On day 9, leptospira serology was positive and doxycycline was added to the treatment strategy. With combination therapy, the patient recovered from the infection. In most cases, similar clinical presentations make the diagnosis of concurrent infections of febrile diseases difficult, and serious complications can develop as a consequence of delayed treatment. As with this case, if the patient initially has serious a medical condition caused by complications, and does not clinically respond to initial standard antibiotics therapy or has an unusual course of disease, concurrent infection must be considered.