A-Z Index × Submit A-Z Index × Submit A-Z Index Search Dropdown × Submit Facebook Twitter LinkedIn Syndicate Emerging Infectious Disease journal ISSN: 1080-6059 Disclaimer: Early release articles are not considered as final versions. Any changes will be reflected in the online version in the month the article is officially released.
We report a systematic case review of antemortem neurosurgical resections and biopsies and outcomes including new lesions after procedure and survival in Balamuthia mandrillaris granulomatous amebic encephalitis. The investigation was prompted by a 5-year-old patient in the southwestern United States who was treated with nitroxoline, the 2021 Centers for Disease Control and Prevention regimen, and underwent 2 resections; initial resection site recurrence and a new lesion after resection prompted the question whether complete resection versus biopsy is associated with better outcomes. We conducted a literature review and found no substantial difference between neurosurgical resection versus biopsy-only groups. Limitations include case review, number of cases, and incomplete data available. Additional analyses comparing neurosurgical outcomes with outcomes of those diagnosed via blood or cerebrospinal fluid and metagenomic next-generation sequencing might provide more definitive answers. This case and systematic review provide evidence that treatment with nitroxoline and neurosurgical resection could contribute to survival in Balamuthia encephalitis case-patients.
Free-living amebae (FLA) are soil- and water-dwelling unicellular organisms found throughout the world that cause rare but often fatal infections ( 1 , 2 ). Acanthamoeba and Balamuthia are 2 genera of FLA that cause granulomatous amebic encephalitis (GAE), a subacute disease characterized by focal neurologic deficits, altered mental status, and > 1 parenchymal brain lesions on imaging. The true incidence is unclear because of diagnostic and reporting limitations, but in the United States, <20 cases are reported annually; however, >90% of infected patients who have central nervous system (CNS) involvement die ( 1 , 2 ).
Acanthamoeba spp. FLA primarily affect immunocompromised hosts, whereas Balamuthia mandrillaris amebae also infect immunocompetent hosts. Balamuthia spp. amebae exist as environmentally stable cysts and infectious trophozoites, entering the body through the respiratory tract or open skin wounds and spreading hematogenously to the organs, most notably the brain ( 2 – 9 ). Balamuthia was first identified in a pregnant mandrill ( Papio sphinx ) in 1990, but as a result, posthumous human diagnoses were made dating back to 1974 ( 10 ). Since then, B. mandrillaris GAE cases have been diagnosed worldwide, many among children, and often with fatal outcomes. A review of 109 US cases during 1974–2016 revealed a 90% mortality rate ( 2 ). Even when infections are diagnosed antemortem and patients receive antiamebic medications, the fatality rate exceeds 75% ( 11 ).
The Centers for Disease Control and Prevention (CDC) recommends a regimen for B. mandrillaris GAE including pentamidine, sulfadiazine, azithromycin or clarithromycin, a triazole, flucytosine, and miltefosine ( 12 ). In 2025, CDC added nitroxoline to the recommended regimen ( 12 ). A study published in 2018, screened 2,177 clinically approved compounds (including the CDC-recommended regimen) for in vitro activity against B. mandrillaris amebae ( 13 ) . A quinoline antibiotic, nitroxo…