By Stan Deresinski, MD, FACP, FIDSA
Clinical Professor of Medicine, Stanford University
SYNOPSIS: This study from the Centers for Disease Control and Prevention reviewed 10 cases of patients with a history of nasal rinsing who developed Acanthamoeba infection.
SOURCE: Haston JC, Serra C, Imada E, et al. Acanthamoeba infection and nasal rinsing, United States, 1994-2022. Emerg Infect Dis 2024;30. https://doi.org/10.3201/eid300...
Haston and colleagues, using the Centers for Disease Control and Prevention (CDC) Free-Living Amebae database and after excluding cases of keratitis, identified 10 patients in the United States with a history of nasal rinsing who developed Acanthamoeba infection. The cases occurred in 1994-2022, but 9/10 cases were from 2015-2022. The median age was 62 years (range 32-80 years). Each of the 10 patients had at least one immunocompromising condition. Five patients had a malignancy, including chronic lymphocytic leukemia in four patients and acute myelogenous leukemia in one patient. Other conditions (each patient may have had more than one) included acquired immunodeficiency syndrome (AIDS), stem cell or solid organ transplantation, microscopic polyangiitis, and chronic renal disease. Seven patients reported a history of chronic sinusitis.
Nine patients reported the reasons for nasal rinsing, with seven doing it for relief of chronic sinusitis symptoms and two doing it as ritual. A water source was reported by five patients. Four patients used tap water, while the fifth used sterile water but then submerged their device in tap water.
Identified Acanthamoeba infections included rhinosinusitis in nine patients, granulomatous amebic encephalitis (GAE) in six patients, cutaneous disease in six patients, osteomyelitis in three patients, and pulmonary disease and endophthalmitis in one each. The diagnosis most often was made by polymerase chain reaction (PCR), with histopathology, immunohistochemical staining, and indirect immunofluorescence also used. Seven patients survived (there is no mention of treatment approach), which included three of six patients with GAE.
COMMENTARY
Acanthamoeba are free-living amoeba found in soil and water, including tap water. They most commonly cause keratitis, most often in contact lens wearers, but they may cause infections at many anatomic sites, as in this series. Among these, the most likely to have been lethal are the ones causing encephalitis.
The CDC recommends that patients be made aware of the danger of using tap water for nasal rinsing. Instead, they recommend using boiled, distilled, or sterile water to prevent infection, not only with Acanthamoeba, but also with, e.g., Naegleria, some non-tuberculous mycobacteria, and possibly Balamuthia.
As the CDC indicates, they offer a 24/7 Free-Living Ameba Consultation Service for diagnostic support and treatment recommendations. Healthcare providers can call the CDC Emergency Operations Center at (770) 488-7100 for a consultation for any confirmed or suspected Acanthamoeba infection.
