A Case of Infection with Leptospires from Three Different Serovars During a Flood in the Philippines.

Leptospirosis a significant and life-threatening zoonosis with global reach. If diagnosis and treatment are delayed, the infection may lead to fatal Weil's disease. In the Philippines, a 21-year-old man was admitted to the hospital with leptospirosis-like symptoms, including fever, myalgia, headache, anuria, jaundice, hemorrhage, skin rash, and diarrhea. Although he was immediately treated with penicillin G, the patient died shortly after admission. The serological test result was negative for Leptospira; however, three leptospires were isolated from the patient through selective cultivation under varying conditions. Microscopic agglutination tests and a phylogenetic analysis of the flaB gene encoding the flagellin subunit protein revealed that the isolates belonged to three different serovars, suggesting that the patient was simultaneously infected with at least three distinct Leptospira serovars. In this case report, we highlight the potential risk of multiple infections with leptospires in humans, a critical consideration for diagnosis and treatment strategies.