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Fatal Granulomatous Amoebic Encephalitis Caused by Acanthamoeba in a Patient With Kidney Transplant: A Case Report

Fatal Granulomatous Amoebic Encephalitis Caused by Acanthamoeba in a Patient With Kidney... BRIEF R EP ORT aphasia with impaired naming, intact repetition, and ability to Fatal Granulomatous Amoebic follow simple commands. Cranial nerves and motor function Encephalitis Caused by were intact: deep tendon reflexes were 2+ and symmetric. She had downgoing toes bilaterally. Sensory function was intact ex- Acanthamoeba in a Patient With cept for decreased vibration bilaterally in the distal lower ex- Kidney Transplant: A Case Report tremities. Cerebellar function was intact and gait was normal. Home transplant-related medications included tacrolimus, my- 1 2 3 1 Ahmad Salameh, Nancy Bello, Jennifer Becker, and Tirdad Zangeneh cophenolate mofetil, prednisone, and valganciclovir for cyto- Division of Infectious Diseases, Department of Medicine, and Departments of megalovirus prophylaxis. Noncontrast CT head scan revealed 2 3 Neurology; and Radiology, University of Arizona, Tucson hypodensity with mild mass effect in the left temporal lobe and insular cortex with the radiological differential diagnosis in- Granulomatous amoebic encephalitis (GAE) due to Acan- cluding encephalitis and acute stroke. An MRI of the brain with thamoeba is almost a uniformly fatal infection in immune- contrast showed diffuse, T2 hyperintense lesion of the left tem- compromised hosts despite multidrug combination therapy. poral lobe, and insular cortex. This was associated with patchy We report a case of GAE in a female who received a deceased cytotoxic edema and focal, subtle enhancement with a tiny sin- donor kidney graft. She was treated with a combination of gle focus of necrosis. There were multiple microhemorrhages miltefosine, pentamidine, sulfadiazine, fluconazole, flucyto- within and remote from this region. Appearances were of atyp- sine, and azithromycin. ical infectious encephalitis with microhemorrhages secondary Keywords. Acanthamoeba; encephalitis; granulomatous to either a necrotizing vasculitis or arising from a central embol- amoebic; immunosuppression; transplantation. ic source (Figure 1A). Treatment with acyclovir was initiated empirically for concerns of herpes simplex virus (HSV) enceph- alitis. On follow-up neurologic examinations, her mental status CASE REPORT continued to fluctuate with speech impairment and hallucina- tions, which prompted electroencephalography that demonstrat- A 64-year-old woman underwent deceased donor kidney trans- ed diffuse slowing and a lumbar puncture with cerebrospinal plantation due to diabetic nephropathy with uneventful recov- fluid (CSF) analysis showing 12 white blood cells (80% lympho- ery postoperatively and who had no known episodes of cytes, 14% monocytes, and 6% neutrophils), protein of 53 mg/dL, rejection. Seven months after transplantation, she presented and glucose of 61 mg/dL. Acyclovir was later discontinued after with an episode of confusion that was attributed to a recurrent CSF HSV polymerase chain reaction (PCR) testing resulted in urinary tract infection and after treatment she was discharged negative findings. On hospital day 10, her mental status contin- home. A noncontrast computed tomography (CT) head scan ued to deteriorate and repeat MRI of the brain (Figure 1B) and magnetic resonance imaging (MRI) of the brain at this showed interval progression of cerebritis with more areas of time were normal. She returned 10 days later with intermittent the brain involvement and increased mass effect with midline confusion and word-finding difficulty. A physical examination shift; in addition, there was an increased number of the micro- was notable for a nontoxic-appearing woman with stable vital hemorrhages and increased peripheral lesion enhancement. An signs. She was awake and alert but oriented to person only. Infectious Diseases consultation was requested. The following Speech was intact: language evaluation revealed expressive day, she underwent stereotactic left craniotomy with left tempo- ral lobe brain biopsy. With disease progression, the patient’s mental status progressively deteriorated: she became more le- Received 19 March 2015; accepted 6 July 2015. Correspondence: Ahmad Salameh, MD, Division of Infectious Diseases, Department of In- thargic and developed right arm weakness. Microscopy of the ternal Medicine, University of Arizona, 1501 N Campbell Ave., Tucson, AZ 85724 (asalameh@ biopsy specimen showed necrotizing granulomas with acute in- deptofmed.arizona.edu). flammation, with microorganisms morphologically consistent Open Forum Infectious Diseases © The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases with amoeba. Photomicrographs were sent to the Centers for Society of America. This is an Open Access article distributed under the terms of the Creative Disease Control and Prevention (CDC) for telediagnosis. The Commons Attribution-NonCommercial-NoDerivs licence (http://creativecommons.org/licenses/ by-nc-nd/4.0/), which permits non-commercial reproduction and distribution of the work, in any Centers for Disease Control and Prevention experts reviewed medium, provided the original work is not altered or transformed in any way, and that the work the images on day 13, and it was their opinion that the images is properly cited. For commercial re-use, please contact journals.permissions@oup.com. DOI: 10.1093/ofid/ofv104 showed free-living amoebae of the Acanthamoeba/Balamuthia BRIEF REPORT OFID 1 � � Figure 1. (A–C) T2 brain magnetic resonance imaging of the patient with granulomatous amoebic encephalitis caused by Acanthamoeba. Brain imaging demonstrates progressive changes of cerebritis visible as T2 hyperintensity with mass effect that initially involves the anterior temporal lobe progressing to affect most of the left cerebral hemisphere, with increased mass effect and multiple areas of necrosis. type. Hematoxylin and eosin (H&E) and unstained slides were reptiles, birds, mammals, and various water samples including sent to the CDC laboratory for immunohistochemical confir- fresh water, seawater, tap water, bottled mineral water, indoor/ mation, which was consistent with Acanthamoeba species (Fig- outdoor swimming pools, aquariums, and sewage [1]. Tropho- ure 2A–D). A multidrug regimen was initiated that included zoites are small, usually 15–35 µm in length, and oval to trian- miltefosine, pentamidine, sulfadiazine, flucytosine, fluconazole, gular in shape when moving. Smaller, 10–15 µm in diameter, and azithromycin. Methicillin-resistant Staphylococcus aureus double-walled cysts form under unfavorable conditions of was grown from brain tissue biopsy; therefore, treatment with high temperature and osmolarity and low pH, especially in parenteral vancomycin was initiated. Both tacrolimus and my- nutrient-poor environments [1, 2]. The clinical syndromes asso- cophenolate were discontinued, and prednisone was tapered off ciated with Acanthamoeba infections remain rare. Aside from over several days. Acanthamoeba serology sent to the CDC lab- the well known Acanthamoeba keratitis associated with the oratories to monitor response of therapy was negative. John use of contaminated contact lenses in the presence of microab- Cunningham (JC) virus PCR was reported as positive with rasions of the cornea, granulomatous amoebic encephalitis 51 copies/mL, but there was no evidence of progressive multifo- (GAE) is being recognized more frequently, especially with cal leukoencephalopathy features on brain biopsy. Patient kid- the growing population of immune-compromised hosts [3]. ney function deteriorated, and antimicrobials were adjusted for As such, GAE is now being diagnosed at the time of acute illness renal function. Unlike Balamuthia, Acanthamoeba has not been presentation, rather than at post mortem examination [4, 5]. Up documented to be transmitted by solid organ transplant, and to to 80% of the population is seropositive to various Acanthamoe- exclude this possibility, further investigation and contact to ba spp [6], but only a minority develop clinically significant ill- transplant centers, including examination of donor samples, nesses. Early clinical diagnosis can be difficult with symptoms revealed that our patient’s infection was not a donor-derived often mimicking ischemic stroke or other infectious encephalit- infection and was most likely acquired by environmental expo- ides [5]. Imaging findings in the early stages of infection are sure. The patient’s condition deteriorated despite being on com- often nonspecific. Lesions are either multifocal, with discrete bination antimicrobial therapy, and she eventually developed focal lesions at the grey/white matter junction, or present as a right-sided hemiplegia then coma. Repeat MRI of the showed larger solitary mass-like lesion. Depending on the location of further interval progression with worsening cerebritis, now in- the lesion(s) within the brain, there is a wide differential diag- volving most of the left cerebral hemisphere and left midbrain. nosis that often includes infectious etiology, low-grade glioma, There was significantly increased mass effect (Figure 1C). Hos- lymphoma, or demyelinating disease [5]. Acanthamoeba is tra- pice care was initiated at the family’s request and the patient ditionally described as affecting the posterior structures of the died 3 days later. brain [7]. However, as in our case, which initially affected the left temporal lobe, reported cases have been described in various brain lobes and brainstem structures often with an associated DISCUSSION meningoencephalitis [7–9]. With worsening infection, eventually Acanthamoeba is a genus of amoebae, and it is a free-living op- the signs of raised intracranial pressure develop invariably lead- portunistic protozoan ubiquitous in nature. It has been isolated ing to coma and death. Diagnosis is usually only confirmed with from soil, dust, sand, nasal swab samples, feces, vegetables, fish, brain biopsy. This can delay the diagnosis and commencement of 2 OFID BRIEF REPORT � � Figure 2. (A) Brain biopsy sections of the same patient stained with hematoxylin and eosin showing a dense granulomatous infiltrate accompanied by microorganisms morphologically consistent with free-living amoeba (arrow). (B) Higher magnification of (A) showing the characteristic nuclear appearance of the amoeba. (C) Indirect immunofluorescence labeling of brain biopsy sections performed using a rabbit serum (1:100, R150, exposed to Acanthamoeba castellanii whole-cell lysate) followed by 1:200 fluorescein isothiocyanate-conjugate goat anti-rabbit immunoglobulin G (F6005; Sigma-Aldrich): at low magnification, the photomicrograph shows fluorescent microorganisms around blood vessels. (D) High magnification photomicrograph showing 2 Acantha- moebae fluorescing bright green after indirect immunofluorescence. treatment and may contribute to the subsequent fatal outcome, microhemorrhages. The volume of affected brain tissue and ne- particularly in the immune-compromised patients [2, 4, 6]. crosis increased in size. The enhancement pattern of the largest There are no reported cases of donor-derived infections with lesion evolved over time: initially focal and asymmetric eventu- Acanthamoeba unlike Balamuthia mandrillaris,another free- ally becoming a peripheral thin rim. This would confirm an in- living amoeba that has been reported to result from donor- flammatory zone that has been previously shown histologically derived infections in organ recipients. Our patient’s donor to correlate with an inflammatory response secondary to amoe- had negative tissue examination for Acanthamoeba [10]. Ce- bic trophozoite infiltration of the pial vessels and a border zone rebrospinal fluid analysis in GAE demonstrates lymphocytic encephalitis [9]. pleocytosis, low glucose, and high protein. Careful examination Multiple antimicrobials have been used in the treatment of of CSF cytology may rarely reveal the trophozoites [8]. Acantha- GAE in various combinations that include, but are not limited moeba serology can potentially be used to follow disease activity to, trimethoprim/sulfamethoxazole, pentamidine, sulfadiazine, [11,12]. Histologic examination of tissue specimens such as skin pyrimethamine, azithromycin, rifampin, flucytosine, albenda- or brain biopsies with the regular (H&E) staining can be diag- zole, miltefosine, metronidazole, ketoconazole, fluconazole, nostic. Antigen detection of Acanthamoeba using indirect im- voriconazole, and amphotericin B. Polymicrobial therapy is po- munofluorescence testing in tissue specimens and molecular tentially more effective if combined with resection of the lesions diagnostics with PCR are available in some laboratories, includ- to better control the infection. Among all the solid organ trans- ing US CDC laboratories [4]. plant recipients, there was only 1 case report in the English As our patient’s clinical condition deteriorated, all the cere- literature of a survivor with liver transplant who was on cyclo- bral lesions enlarged with the appearance of multiple new sporine monotherapy as an immunosuppressant at the time of BRIEF REPORT OFID 3 � � diagnosis. He underwent resection of the brain lesion followed References by trimethoprim/sulfamethoxazole and rifampin treatment 1. Ahmed Khan N. Pathogenesis of Acanthamoeba infections. Microb [13]. Minimal immunosuppression can also provide a favorable Pathog 2003; 34:277–85. 2. Martinez A, Janitschke K. Acanthamoeba, an opportunistic microor- outcome if coupled with effective surveillance and increased ganism: a review. Infection 1985; 13:251–6. awareness of such infections. 3. Khan N. Acanthamoeba and the blood-brain barrier: the breakthrough. J Med Microbiol 2008; 57:1051–7. CONCLUSION 4. Zamora A, Henderson H, Swiatlo E. Acanthamoeba encephalitis: a case report and review of therapy. Surg Neurol Int 2014; 5:68. 5. McKellar M, Mehta L, Greenlee J, et al. Fatal granulomatous Acantha- Although rare, Acanthameoba infection is associated with sev- moeba encephalitis mimicking a stroke, diagnosed by correlation of re- eral clinical presentations such as keratitis, skin infections, si- sults of sequential magnetic resonance imaging, biopsy, in vitro culture, nusitis, and pneumonitis. Disseminated infections are being immunofluorescence analysis, and molecular analysis. J Clin Microbiol 2006; 44:4265–9. reported more frequently, especially in the immune-suppressed 6. Chappell C, Wright J, Coletta M, Newsome A. Standardized method of hosts that include GAE. Disseminated infections used to be a measuring Acanthamoeba antibodies in sera from healthy human sub- post mortem diagnosis, but with the increased index of suspi- jects. Clin Diagn Lab Immunol 2001; 8:724–30. 7. Sell J, Rupp F, Orrison W Jr. Granulomatous amebic encephalitis caused cion of such infections and the newer methods of diagnosis, ear- by Acanthamoeba. Neuroradiology 1997; 39:434–6. lier detection and treatment can be achieved. Unfortunately, the 8. Petry F, Torzewski M, Bohl J, et al. Early diagnosis of Acanthamoeba disseminated disease is usually fatal in 85% of cases (94 cases infection during routine cytological examination of cerebrospinal reported to CDC from 1955 to 2013) [4]. The few survivors of fluid. J Clin Microbiol 2006; 44:1903–4. 9. Chandra S, Adwani S, Mahadevan A. Acanthamoeba meningoenceph- GAE received combination antimicrobial therapy. Regimens alitis. Ann Indian Acad Neurol 2014; 17:108–12. that include miltefosine have shown efficacy to treat both Bala- 10. Centers for Disease Control and Prevention (CDC). Balamuthia man- muthia and Acanthamoeba infections, but that is based only on drillaris transmitted through organ transplantation — Mississippi, 2009. MMWR Morb Mortal Wkly Rep 2010; 59:1165–70. case reports, given the rarity of these infections [11]. 11. Aichelburg A, Walochnik J, Assadian O, et al. Successful treatment of disseminated Acanthamoeba sp. infection with miltefosine. Emerg In- Acknowledgments fect Dis 2008; 14:1743–6. We thank Naomi Rance for providing explanation of histopathology fig- 12. Bloch K, Schuster F. Inability to make a premortem diagnosis of Acan- ures. We thank Jennifer Cope for her contributions, reading the manuscript, thamoeba species infection in a patient with fatal granulomatous ame- and giving valuable comments. bic encephalitis. J Clin Microbiol 2005; 43:3003–6. Potential conflicts of interest. All authors: No reported conflicts. 13. Fung K, DhillonA,McLaughlinJ,et al. Cure of Acanthamoeba All authors have submitted the ICMJE Form for Disclosure of Potential cerebral abscess in a liver transplant patient. Liver Transpl 2008;14: Conflicts of Interest. 308–12. 4 OFID BRIEF REPORT � � http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Open Forum Infectious Diseases Oxford University Press

Fatal Granulomatous Amoebic Encephalitis Caused by Acanthamoeba in a Patient With Kidney Transplant: A Case Report

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© The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America.
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Abstract

BRIEF R EP ORT aphasia with impaired naming, intact repetition, and ability to Fatal Granulomatous Amoebic follow simple commands. Cranial nerves and motor function Encephalitis Caused by were intact: deep tendon reflexes were 2+ and symmetric. She had downgoing toes bilaterally. Sensory function was intact ex- Acanthamoeba in a Patient With cept for decreased vibration bilaterally in the distal lower ex- Kidney Transplant: A Case Report tremities. Cerebellar function was intact and gait was normal. Home transplant-related medications included tacrolimus, my- 1 2 3 1 Ahmad Salameh, Nancy Bello, Jennifer Becker, and Tirdad Zangeneh cophenolate mofetil, prednisone, and valganciclovir for cyto- Division of Infectious Diseases, Department of Medicine, and Departments of megalovirus prophylaxis. Noncontrast CT head scan revealed 2 3 Neurology; and Radiology, University of Arizona, Tucson hypodensity with mild mass effect in the left temporal lobe and insular cortex with the radiological differential diagnosis in- Granulomatous amoebic encephalitis (GAE) due to Acan- cluding encephalitis and acute stroke. An MRI of the brain with thamoeba is almost a uniformly fatal infection in immune- contrast showed diffuse, T2 hyperintense lesion of the left tem- compromised hosts despite multidrug combination therapy. poral lobe, and insular cortex. This was associated with patchy We report a case of GAE in a female who received a deceased cytotoxic edema and focal, subtle enhancement with a tiny sin- donor kidney graft. She was treated with a combination of gle focus of necrosis. There were multiple microhemorrhages miltefosine, pentamidine, sulfadiazine, fluconazole, flucyto- within and remote from this region. Appearances were of atyp- sine, and azithromycin. ical infectious encephalitis with microhemorrhages secondary Keywords. Acanthamoeba; encephalitis; granulomatous to either a necrotizing vasculitis or arising from a central embol- amoebic; immunosuppression; transplantation. ic source (Figure 1A). Treatment with acyclovir was initiated empirically for concerns of herpes simplex virus (HSV) enceph- alitis. On follow-up neurologic examinations, her mental status CASE REPORT continued to fluctuate with speech impairment and hallucina- tions, which prompted electroencephalography that demonstrat- A 64-year-old woman underwent deceased donor kidney trans- ed diffuse slowing and a lumbar puncture with cerebrospinal plantation due to diabetic nephropathy with uneventful recov- fluid (CSF) analysis showing 12 white blood cells (80% lympho- ery postoperatively and who had no known episodes of cytes, 14% monocytes, and 6% neutrophils), protein of 53 mg/dL, rejection. Seven months after transplantation, she presented and glucose of 61 mg/dL. Acyclovir was later discontinued after with an episode of confusion that was attributed to a recurrent CSF HSV polymerase chain reaction (PCR) testing resulted in urinary tract infection and after treatment she was discharged negative findings. On hospital day 10, her mental status contin- home. A noncontrast computed tomography (CT) head scan ued to deteriorate and repeat MRI of the brain (Figure 1B) and magnetic resonance imaging (MRI) of the brain at this showed interval progression of cerebritis with more areas of time were normal. She returned 10 days later with intermittent the brain involvement and increased mass effect with midline confusion and word-finding difficulty. A physical examination shift; in addition, there was an increased number of the micro- was notable for a nontoxic-appearing woman with stable vital hemorrhages and increased peripheral lesion enhancement. An signs. She was awake and alert but oriented to person only. Infectious Diseases consultation was requested. The following Speech was intact: language evaluation revealed expressive day, she underwent stereotactic left craniotomy with left tempo- ral lobe brain biopsy. With disease progression, the patient’s mental status progressively deteriorated: she became more le- Received 19 March 2015; accepted 6 July 2015. Correspondence: Ahmad Salameh, MD, Division of Infectious Diseases, Department of In- thargic and developed right arm weakness. Microscopy of the ternal Medicine, University of Arizona, 1501 N Campbell Ave., Tucson, AZ 85724 (asalameh@ biopsy specimen showed necrotizing granulomas with acute in- deptofmed.arizona.edu). flammation, with microorganisms morphologically consistent Open Forum Infectious Diseases © The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases with amoeba. Photomicrographs were sent to the Centers for Society of America. This is an Open Access article distributed under the terms of the Creative Disease Control and Prevention (CDC) for telediagnosis. The Commons Attribution-NonCommercial-NoDerivs licence (http://creativecommons.org/licenses/ by-nc-nd/4.0/), which permits non-commercial reproduction and distribution of the work, in any Centers for Disease Control and Prevention experts reviewed medium, provided the original work is not altered or transformed in any way, and that the work the images on day 13, and it was their opinion that the images is properly cited. For commercial re-use, please contact journals.permissions@oup.com. DOI: 10.1093/ofid/ofv104 showed free-living amoebae of the Acanthamoeba/Balamuthia BRIEF REPORT OFID 1 � � Figure 1. (A–C) T2 brain magnetic resonance imaging of the patient with granulomatous amoebic encephalitis caused by Acanthamoeba. Brain imaging demonstrates progressive changes of cerebritis visible as T2 hyperintensity with mass effect that initially involves the anterior temporal lobe progressing to affect most of the left cerebral hemisphere, with increased mass effect and multiple areas of necrosis. type. Hematoxylin and eosin (H&E) and unstained slides were reptiles, birds, mammals, and various water samples including sent to the CDC laboratory for immunohistochemical confir- fresh water, seawater, tap water, bottled mineral water, indoor/ mation, which was consistent with Acanthamoeba species (Fig- outdoor swimming pools, aquariums, and sewage [1]. Tropho- ure 2A–D). A multidrug regimen was initiated that included zoites are small, usually 15–35 µm in length, and oval to trian- miltefosine, pentamidine, sulfadiazine, flucytosine, fluconazole, gular in shape when moving. Smaller, 10–15 µm in diameter, and azithromycin. Methicillin-resistant Staphylococcus aureus double-walled cysts form under unfavorable conditions of was grown from brain tissue biopsy; therefore, treatment with high temperature and osmolarity and low pH, especially in parenteral vancomycin was initiated. Both tacrolimus and my- nutrient-poor environments [1, 2]. The clinical syndromes asso- cophenolate were discontinued, and prednisone was tapered off ciated with Acanthamoeba infections remain rare. Aside from over several days. Acanthamoeba serology sent to the CDC lab- the well known Acanthamoeba keratitis associated with the oratories to monitor response of therapy was negative. John use of contaminated contact lenses in the presence of microab- Cunningham (JC) virus PCR was reported as positive with rasions of the cornea, granulomatous amoebic encephalitis 51 copies/mL, but there was no evidence of progressive multifo- (GAE) is being recognized more frequently, especially with cal leukoencephalopathy features on brain biopsy. Patient kid- the growing population of immune-compromised hosts [3]. ney function deteriorated, and antimicrobials were adjusted for As such, GAE is now being diagnosed at the time of acute illness renal function. Unlike Balamuthia, Acanthamoeba has not been presentation, rather than at post mortem examination [4, 5]. Up documented to be transmitted by solid organ transplant, and to to 80% of the population is seropositive to various Acanthamoe- exclude this possibility, further investigation and contact to ba spp [6], but only a minority develop clinically significant ill- transplant centers, including examination of donor samples, nesses. Early clinical diagnosis can be difficult with symptoms revealed that our patient’s infection was not a donor-derived often mimicking ischemic stroke or other infectious encephalit- infection and was most likely acquired by environmental expo- ides [5]. Imaging findings in the early stages of infection are sure. The patient’s condition deteriorated despite being on com- often nonspecific. Lesions are either multifocal, with discrete bination antimicrobial therapy, and she eventually developed focal lesions at the grey/white matter junction, or present as a right-sided hemiplegia then coma. Repeat MRI of the showed larger solitary mass-like lesion. Depending on the location of further interval progression with worsening cerebritis, now in- the lesion(s) within the brain, there is a wide differential diag- volving most of the left cerebral hemisphere and left midbrain. nosis that often includes infectious etiology, low-grade glioma, There was significantly increased mass effect (Figure 1C). Hos- lymphoma, or demyelinating disease [5]. Acanthamoeba is tra- pice care was initiated at the family’s request and the patient ditionally described as affecting the posterior structures of the died 3 days later. brain [7]. However, as in our case, which initially affected the left temporal lobe, reported cases have been described in various brain lobes and brainstem structures often with an associated DISCUSSION meningoencephalitis [7–9]. With worsening infection, eventually Acanthamoeba is a genus of amoebae, and it is a free-living op- the signs of raised intracranial pressure develop invariably lead- portunistic protozoan ubiquitous in nature. It has been isolated ing to coma and death. Diagnosis is usually only confirmed with from soil, dust, sand, nasal swab samples, feces, vegetables, fish, brain biopsy. This can delay the diagnosis and commencement of 2 OFID BRIEF REPORT � � Figure 2. (A) Brain biopsy sections of the same patient stained with hematoxylin and eosin showing a dense granulomatous infiltrate accompanied by microorganisms morphologically consistent with free-living amoeba (arrow). (B) Higher magnification of (A) showing the characteristic nuclear appearance of the amoeba. (C) Indirect immunofluorescence labeling of brain biopsy sections performed using a rabbit serum (1:100, R150, exposed to Acanthamoeba castellanii whole-cell lysate) followed by 1:200 fluorescein isothiocyanate-conjugate goat anti-rabbit immunoglobulin G (F6005; Sigma-Aldrich): at low magnification, the photomicrograph shows fluorescent microorganisms around blood vessels. (D) High magnification photomicrograph showing 2 Acantha- moebae fluorescing bright green after indirect immunofluorescence. treatment and may contribute to the subsequent fatal outcome, microhemorrhages. The volume of affected brain tissue and ne- particularly in the immune-compromised patients [2, 4, 6]. crosis increased in size. The enhancement pattern of the largest There are no reported cases of donor-derived infections with lesion evolved over time: initially focal and asymmetric eventu- Acanthamoeba unlike Balamuthia mandrillaris,another free- ally becoming a peripheral thin rim. This would confirm an in- living amoeba that has been reported to result from donor- flammatory zone that has been previously shown histologically derived infections in organ recipients. Our patient’s donor to correlate with an inflammatory response secondary to amoe- had negative tissue examination for Acanthamoeba [10]. Ce- bic trophozoite infiltration of the pial vessels and a border zone rebrospinal fluid analysis in GAE demonstrates lymphocytic encephalitis [9]. pleocytosis, low glucose, and high protein. Careful examination Multiple antimicrobials have been used in the treatment of of CSF cytology may rarely reveal the trophozoites [8]. Acantha- GAE in various combinations that include, but are not limited moeba serology can potentially be used to follow disease activity to, trimethoprim/sulfamethoxazole, pentamidine, sulfadiazine, [11,12]. Histologic examination of tissue specimens such as skin pyrimethamine, azithromycin, rifampin, flucytosine, albenda- or brain biopsies with the regular (H&E) staining can be diag- zole, miltefosine, metronidazole, ketoconazole, fluconazole, nostic. Antigen detection of Acanthamoeba using indirect im- voriconazole, and amphotericin B. Polymicrobial therapy is po- munofluorescence testing in tissue specimens and molecular tentially more effective if combined with resection of the lesions diagnostics with PCR are available in some laboratories, includ- to better control the infection. Among all the solid organ trans- ing US CDC laboratories [4]. plant recipients, there was only 1 case report in the English As our patient’s clinical condition deteriorated, all the cere- literature of a survivor with liver transplant who was on cyclo- bral lesions enlarged with the appearance of multiple new sporine monotherapy as an immunosuppressant at the time of BRIEF REPORT OFID 3 � � diagnosis. He underwent resection of the brain lesion followed References by trimethoprim/sulfamethoxazole and rifampin treatment 1. Ahmed Khan N. Pathogenesis of Acanthamoeba infections. Microb [13]. Minimal immunosuppression can also provide a favorable Pathog 2003; 34:277–85. 2. Martinez A, Janitschke K. Acanthamoeba, an opportunistic microor- outcome if coupled with effective surveillance and increased ganism: a review. Infection 1985; 13:251–6. awareness of such infections. 3. Khan N. Acanthamoeba and the blood-brain barrier: the breakthrough. J Med Microbiol 2008; 57:1051–7. CONCLUSION 4. Zamora A, Henderson H, Swiatlo E. Acanthamoeba encephalitis: a case report and review of therapy. Surg Neurol Int 2014; 5:68. 5. McKellar M, Mehta L, Greenlee J, et al. Fatal granulomatous Acantha- Although rare, Acanthameoba infection is associated with sev- moeba encephalitis mimicking a stroke, diagnosed by correlation of re- eral clinical presentations such as keratitis, skin infections, si- sults of sequential magnetic resonance imaging, biopsy, in vitro culture, nusitis, and pneumonitis. Disseminated infections are being immunofluorescence analysis, and molecular analysis. J Clin Microbiol 2006; 44:4265–9. reported more frequently, especially in the immune-suppressed 6. Chappell C, Wright J, Coletta M, Newsome A. Standardized method of hosts that include GAE. Disseminated infections used to be a measuring Acanthamoeba antibodies in sera from healthy human sub- post mortem diagnosis, but with the increased index of suspi- jects. Clin Diagn Lab Immunol 2001; 8:724–30. 7. Sell J, Rupp F, Orrison W Jr. Granulomatous amebic encephalitis caused cion of such infections and the newer methods of diagnosis, ear- by Acanthamoeba. Neuroradiology 1997; 39:434–6. lier detection and treatment can be achieved. Unfortunately, the 8. Petry F, Torzewski M, Bohl J, et al. Early diagnosis of Acanthamoeba disseminated disease is usually fatal in 85% of cases (94 cases infection during routine cytological examination of cerebrospinal reported to CDC from 1955 to 2013) [4]. The few survivors of fluid. J Clin Microbiol 2006; 44:1903–4. 9. Chandra S, Adwani S, Mahadevan A. Acanthamoeba meningoenceph- GAE received combination antimicrobial therapy. Regimens alitis. Ann Indian Acad Neurol 2014; 17:108–12. that include miltefosine have shown efficacy to treat both Bala- 10. Centers for Disease Control and Prevention (CDC). Balamuthia man- muthia and Acanthamoeba infections, but that is based only on drillaris transmitted through organ transplantation — Mississippi, 2009. MMWR Morb Mortal Wkly Rep 2010; 59:1165–70. case reports, given the rarity of these infections [11]. 11. Aichelburg A, Walochnik J, Assadian O, et al. Successful treatment of disseminated Acanthamoeba sp. infection with miltefosine. Emerg In- Acknowledgments fect Dis 2008; 14:1743–6. We thank Naomi Rance for providing explanation of histopathology fig- 12. Bloch K, Schuster F. Inability to make a premortem diagnosis of Acan- ures. We thank Jennifer Cope for her contributions, reading the manuscript, thamoeba species infection in a patient with fatal granulomatous ame- and giving valuable comments. bic encephalitis. J Clin Microbiol 2005; 43:3003–6. Potential conflicts of interest. All authors: No reported conflicts. 13. Fung K, DhillonA,McLaughlinJ,et al. Cure of Acanthamoeba All authors have submitted the ICMJE Form for Disclosure of Potential cerebral abscess in a liver transplant patient. Liver Transpl 2008;14: Conflicts of Interest. 308–12. 4 OFID BRIEF REPORT � �

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