No abstract

Here we present the neuropathological, ultrastructural, and radiological features of Sappinia diploidea, a newly recognized human pathogen. The patient was a 38-year-old man with visual disturbances, headache, and a seizure. Brain images showed a solitary mass in the posterior left temporal lobe. The mass was composed of necrotizing hemorrhagic inflammation that contained free-living amebae. Immunofluorescence microscopy showed that the organism was not a species of ameba previously known to cause encephalitis. Trophozoites had a highly distinctive double nucleus, and transmission electron microscopy confirmed that they contained 2 nuclei closely apposed along a flattened surface. The 2 nuclei were attached to each other by distinctive connecting perpendicular filaments. This and several other unique structural features led to the diagnosis of S. diploidea encephalitis. The patient was treated postoperatively with a sequential regimen of anti-amebic drugs (azithromycin, pentamidine, itraconazole, and flucytosine) and is alive after 5 years. Guidelines to recognize future cases of S. diploidea encephalitis are as follows. 1) It presented as a tumor-like cerebral mass without an abscess wall. 2) It had central necrotic and hemorrhagic inflammation that contained acute and chronic inflammatory cells without granulomas or eosinophils. 3) It contained trophozoites (40-70 microm diameter) that contained a distinctive double nucleus. 4) Cyst forms in the host were not excluded or definitely evident. 5) Trophozoites engulfed host blood cells and were stained brightly with Giemsa and periodic acid-Schiff. 6) Trophozoites often were present in viable brain parenchyma on the periphery of the mass without inflammatory response. 7) The prognosis after surgical excision and medical treatment was favorable in this instance.

Central nervous system phaeohyphomycosis remains an unusual disease; however, its incidence has been increasing in recent years. The prognosis of this condition is still poor, despite medical and surgical interventions. Aggressive diagnostic approaches and careful interpretation of cultures might modify the natural history of this disease.

Cellulitis is usually caused by organisms such as beta-hemolytic streptococci and Staphylococcus aureus. Citrobacter are gram-negative bacilli that can cause opportunistic infections in immunocompromised hosts. They are rarely implicated in skin or soft tissue infections. The genus Citrobacter has been respeciated according to genetic relatedness. Citrobacter braakii refers to the genomospecies 6 of the Citrobacter freundii complex. There are no detailed studies of infections caused by the newly formed specific genetic species. We report a case of C. braakii infection in a renal transplant patient receiving immunosuppressive therapy. The patient's lower extremity cellulitis did not respond to conventional antibiotic therapy. Blood cultures grew C. braakii. Sensitivity studies and treatment with appropriate antibiotics resulted in prompt recovery. Immunosuppressive therapy in renal transplant recipients predisposes to infection by unusual pathogens, and this should be suspected when lack of a clinical response to conventional antibiotics is observed. We believe this is the first reported case of C. braakii cellulitis and bacteremia in a renal transplant recipient.

No abstract