Right basal bronchial fistula due to amebic infection: a case report.

BACKGROUND: Pleuropulmonary amebiasis is the second most common form of extraintestinal invasive amebiasis, but cases that include bronchopleural fistula are rare. CASE PRESENTATION: A 43-year-old male was referred to our hospital for liver abscess, right pleural effusion, and body weight loss. He was diagnosed with a bronchopleural fistula caused by invasive pleuropulmonary amebiasis and human immunodeficiency virus (HIV) infection. After initial medical treatment for HIV infection and invasive amebiasis, he underwent pulmonary resection of the invaded lobe. Intraoperative inspection revealed a fistula of the right basal bronchus in the perforated lung abscess cavity, but the diaphragm was intact. The patient was discharged on postoperative day 3 and was in good condition at the 1-year follow-up. CONCLUSIONS: Clinicians should be aware that pleuropulmonary amebiasis can cause a bronchopleural fistula although it is very rare.

Lately Diagnosed Acanthamoeba Keratitis Manifesting as an Intrastromal Corneal Abscess: A Case Report.

ABSTRACT: A 42-year-old female contact lens wearer presented to a local emergency department with a 3-day history of decreased vision and ocular discomfort in her right eye. She was started on topical fluorometholone and oral acyclovir with initial diagnosis of herpes simplex keratitis. After 3 weeks of worsening symptoms, she was diagnosed with bacterial corneal ulcer and treated with levofloxacin eye drops every 2 hr. After 14 days of no improvement, she was referred to our clinic for further workup. Slitlamp examination demonstrated a solitary dense 3×3-mm infiltration involving anterior and central corneal stroma. The overlying epithelium was intact, and there was no subepithelial infiltration, radial perineuritis, keratic precipitates, or anterior chamber reaction. Corneal sensation was normal. Confocal microscopy and corneal biopsy were definitive for Acanthamoeba infection. The patient received polyhexamethylene biguanide 0.02% every 2 hr and oral ketoconazole 200 mg twice a day, which resulted in improvement in her signs and symptoms within 10 days. The medications were gradually tapered off over 5 months per clinical response. At the 9-month follow-up visit, the best-corrected visual acuity was 5/10 with a superficial central stromal scar at slitlamp examination. Acanthamoeba infection should be considered in contact lens wearers who present with intrastromal corneal abscess.

Clinical and molecular diagnosis of Acanthamoeba keratitis in contact lens wearers in southern Brazil reveals the presence of an endosymbiont.

Acanthamoeba keratitis (AK) is an infection that is mostly observed in contact lens wearers. It is often misdiagnosed causing delays in the administration of the correct treatment. The aim of this study was to report the outcome of clinical and molecular diagnosis of AK cases during the summer of 2019 in the southern region of Brazil. Three suspected cases of AK were discovered after an ophthalmic examination at a public hospital in the city of Porto Alegre. These cases were then confirmed through laboratory diagnosis (cell culture and molecular analysis by PCR and sequencing). In each of the three clinical sample cell cultures of corneal scraping and molecular analysis confirmed the presence of Acanthamoeba spp., all belonging to the morphological group II and to the genotype T4, which is the most common genotype associated with AK. In addition, Acanthamoeba spp. isolated from one of the clinical samples was found to harbor the Candidatus Paracaedibacter acanthamoeba, a bacterial endosymbiont. The presence of Ca. Paracaedibacter acanthamoeba in clinical isolates requires further research to reveal its possible role in the pathogenicity of Acanthamoeba infections.

Isolation, identification, and phylogenetic analysis of potentially pathogenic free-living amoebae isolated from nasal and oral mucosa of HIV/AIDS patients in Iran.

The burden of HIV/AIDS in Iran is not as high as in the other countries with high prevalence; however, the number of cases of HIV/AIDs is increasing in this region. According to a recent report, Iran had 5000 (1400-13,000) new cases of HIV infection with 4000 (2500-6200) AIDS-related deaths. Individuals affected by HIV/AIDS are highly susceptible for developing opportunistic infections, e.g. the cerebral complications related to pathogenic free-living amoebae and colonization of free-living amoebae (FLA) can be a serious hazard for patients living with HIV/AIDS. In the present study, a total of 70 oral and nasal mucosal samples were obtained from HIV/AIDS patients referred to the reference hospitals in Iran and tested for the presence of potentially pathogenic FLA using culture and PCR/sequencing-based methods. To discern the taxonomic status of Acanthamoeba genotypes a maximum likelihood phylogenetic tree was constructed and tolerance assays were performed for the positive Acanthamoeba strains. Among the patients with HIV/AIDS referred to the reference hospitals from 2017 to 2019, 7.1% were found positive for pathogenic free-living amoebae. Three strains (HA3, HA4, and HA5) belonged to the T4 genotype, one strain (HA1) was related to the T5 genotype assigned as A. lenticulata, and another strain (HA2) had high homology to Vermamoeba vermiformis. The tolerance assay used for Acanthamoeba strains (HA1, HA3, and HA4) classified these amoebae as highly pathogenic strains. For the most part, the encephalitis cases occurring in HIV/AIDS patients in Iran remain undiagnosed due to lack of awareness of the practitioners on the available diagnostic tools for this lethal infection; therefore, the true incidence of GAE in this region is unknown. A possible colonization with FLA should be considered in the differential diagnosis of suspected cases of CNS infections among HIV/AIDS patients. This study is the first worldwide comprehensive study attempting to isolate and identify the FLA colonization in HIV/AIDS patients. This study highlights the fact that clinicians should be aware of the differential diagnosis of cerebral disease related to FLA in patients with HIV/AIDS.

Non-granulomatous cerebellar infection by Acanthamoeba spp. in an immunocompetent host.

Acanthamoeba spp. is a free-living amoeba, frequently involved in keratitis by contact lens in immunocompetent hosts. Anecdotal reports associate Acanthamoeba spp. as a cause of severe granulomatous encephalitis in immunocompromised and, less frequently, in immunocompetent subjects. Data regarding clinical and therapeutic management are scanty and no defined therapeutic guidelines are available. We describe an unusual case of non-granulomatous Acanthamoeba cerebellitis in an immunocompetent adult male, with abrupt onset of neurological impairment, subtle hemorrhagic infarction at magnetic resonance imaging, and initial suspicion of cerebellar neoplasm. Histopathological findings of excised cerebellar mass revealed the presence of necrosis and inflammation with structure resembling amoebic trophozoites, but without granulomas. Polymerase chain reaction from cerebellar tissue was positive for Acanthamoeba T4 genotype. Due to gastrointestinal intolerance to miltefosine, the patient was treated with long-term course of fluconazole and trimethoprim/sulphamethoxazole, obtaining complete clinical and neuroradiological resolution.

Current and future molecular diagnostics for ocular infectious diseases.

PURPOSE OF REVIEW: Confirmation of ocular infections can pose great challenges to the clinician. A fundamental limitation is the small amounts of specimen that can be obtained from the eye. Molecular diagnostics can circumvent this limitation and have been shown to be more sensitive than conventional culture. The purpose of this review is to describe new molecular methods and to discuss the applications of next-generation sequencing-based approaches in the diagnosis of ocular infections. RECENT FINDINGS: Efforts have focused on improving the sensitivity of pathogen detection using molecular methods. This review describes a new molecular target for Toxoplasma gondii-directed polymerase chain reaction assays. Molecular diagnostics for Chlamydia trachomatis and Acanthamoeba species are also discussed. Finally, we describe a hypothesis-free approach, metagenomic deep sequencing, which can detect DNA and RNA pathogens from a single specimen in one test. In some cases, this method can provide the geographic location and timing of the infection. SUMMARY: Pathogen-directed PCRs have been powerful tools in the diagnosis of ocular infections for over 20 years. The use of next-generation sequencing-based approaches, when available, will further improve sensitivity of detection with the potential to improve patient care.

An autopsy case of Balamuthia mandrillaris amoebic encephalitis, a rare emerging infectious disease, with a brief review of the cases reported in Japan.

Balamuthia mandrillaris is an amoeba found in fresh water and soil that causes granulomatous amoebic encephalitis. We report herein an autopsy case of B. mandrillaris amoebic encephalitis, which was definitely diagnosed by PCR. An 81-year-old man, who had Sjögren's syndrome, manifested drowsiness 2 months before his death with progressive deterioration. Neuroimaging demonstrated foci of T2- and fluid-attenuated inversion recovery high and T1 low-intensity with irregular post-contrast ring enhancement in the cerebral hemisphere, thalamus and midbrain. Pathologically, multiple hemorrhagic and necrotic lesions were found in the cerebrum, thalamus, midbrain, pons, medulla and cerebellum, which were characterized by liquefactive necrosis, marked edema, hemorrhage and necrotizing vasculitis associated with the perivascular accumulation of amoebic trophozoites, a few cysts, and the infiltration of numerous neutrophils and microglia/macrophages. The trophozoites were ovoid or round, 10-60 µm in diameter, and they showed foamy cytoplasm and a round nucleus with small karyosome in the center. The PCR and immunohistochemistry from paraffin-embedded brain specimens revealed angioinvasive encephalitis due to B. mandrillaris. Human cases of B. mandrillaris brain infection are rare in Japan, with only a few brief reports in the literature.

Primary Amoebic Meningoencephalitis.

Primary amoebic meningoencephalitis due to free living amoeba, also called 'brain eating amoeba', Naegleria fowleri, was detected in retroviral disease patient of 40 years who has history of using well water. Patient was admitted with severe headache, fever intermittent, nausea, vomiting and slurring of speech. CT scan and MRI scan findings were normal. CSF examination showed increased protein, low sugar and predominant lymphocytes. CSF was negative for cryptococcal antigen but wet mount preparation showed highly motile free living amoeba Naegleria fowleri. Patient was put on Amphotericin B, Metronidazole, Rifampicin in addition to ART and ATT and other supportive medications. His headache was relieved and patient improved and was discharged on request. Earlier eight cases have been reported from India of which four cases survived the acute episode.

Endosymbiotic Mycobacterium chelonae in a Vermamoeba vermiformis strain isolated from the nasal mucosa of an HIV patient in Lima, Peru.

In March 2010, a 35 year-old HIV/AIDS female patient was admitted to hospital to start treatment with Highly Active Antiretroviral Therapy (HAART) since during a routine control a dramatic decrease in the CD4(+) levels was detected. At this stage, a nasal swab from each nostril was collected from the patient to include it in the samples for the case study mentioned above. Moreover, it is important to mention that the patient was diagnosed in 2009 with invasive pneumococcal disease, acute cholecystitis, pancreatitis and pulmonary tuberculosis. The collected nasal swabs from both nostrils were positive for Vermamoeba vermiformis species which was identified using morphological and PCR/DNA sequencing approaches. Basic Local Alignment Search Tool (BLAST) homology and phylogenetic analysis confirmed the amoebic strain to belong to V.vermiformis species. Molecular identification of the Mycobacterium strain was carried out using a bacterial universal primer pair for the 16S rDNA gene at the genus level and the rpoB gene was amplified and sequenced as previously described to identify the Mycobacterium species (Shin et al., 2008; Sheen et al., 2013). Homology and phylogenetic analyses of the rpoB gene confirmed the species as Mycobacterium chelonae. In parallel, collected swabs were tested by PCR and were positive for the presence of V.vermiformis and M.chelonae. This work describes the identification of an emerging bacterial pathogen,M.chelonae from a Free-Living Amoebae (FLA) strain belonging to the species V.vermiformis that colonized the nasal cavities of an HIV/AIDS patient, previously diagnosed with TB. Awareness within clinicians and public health professionals should be raised, as pathogenic agents such as M.chelonae may be using FLA to propagate and survive in the environment.

Atypical ulcers.

Atypical ulcers of the skin challenge the dermatologist with respect to recognition, diagnosis, management, and treatment. The entire gamut of pathogenic categories including vascular, inflammatory, neoplastic, genetic, medication-related, and infectious processes may give rise to atypical ulcers. By definition, these ulcers are unusual, and accurate diagnosis may ultimately require the clinician to violate the dictum that "common things are common." Atypical ulcers may present with features that the clinician has not previously encountered, or may present with seemingly typical features that actually mislead due to phenotypic mimicry. Because skin ulcers are inherently tissue-destructive, and may reflect an underlying systemic disease process, there is heightened urgency to achieving an accurate diagnosis and initiating appropriate therapy.

Amebic acute appendicitis: systematic review of 174 cases.

BACKGROUND: This study aimed to determine the clinical and demographic features of acute amebic appendicitis by reviewing the reported cases. METHODS: The PubMed and MEDLINE databases were searched to identify articles related to amebic appendicitis using key words. The search included all articles published between 1935 and 2012 without restricting language, journal, or country. RESULTS: A total of 174 cases of amebic appendicitis reported in 42 articles were analyzed. The mean age of the patients was 23.5 years (range 2 months-83 years). The majority of patients were male (74.0 %), and the majority of cases were reported from countries with high/moderate risk for amebiasis (76.5 %). A history of traveling to a high/moderate-risk country was cited in 64.0 % of the overall cases. The interval between travel and onset of clinical symptoms ranged from months to years. History of or coexisting dysenteric diarrhea was present in only 7.0 and 14.0 % of overall cases, respectively. A preoperative diagnosis of amebiasis was cited for only five cases (3.0 %). Complicated appendicitis was present in 30.7 % of cases, some of which required colon resection. Severe postoperative intraabdominal complications (e.g., liver abscess, abdominal sepsis, gastrointestinal fistula, hemorrhage) occurred in 19.4 % of surgery-treated patients. The overall mortality rate was 3.2 %. CONCLUSION: Appendectomy specimens should be routinely sent for histopathologic examination. In the case of suspected amebic acute appendicitis, extra precautions-early appendectomy, metronidazole for antibiotic prophylaxis, wet-preparation examination, obtaining a timely pathology result, increasing the awareness of uncommon complications of appendectomy-can hasten appropriate therapeutic intervention and improve outcome.

A case of fulminant amoebic colitis during systemic chemotherapy for gastric cancer.

Amoebiasis is a parasitic infection caused by the protozoan, Entamoeba histolytica. At times, amoebiasis is activated under immunosuppressive conditions such as chemotherapy. We report a case of fulminant amoebic colitis resulting from an asymptomatic Entamoeba histolytica infection, which was activated by chemotherapy for gastric cancer. The patient developed diarrhea and fever after three courses of chemotherapy for gastric cancer and was diagnosed with acute enteritis. A colonoscopy and biopsy were performed because of the bloody stool. Histopathological findings revealed amoebic invasion of the rectum. Therefore, the patient was diagnosed with amoebic colitis and was treated with metronidazole. Emergency surgery was performed because intestinal perforation was suspected after which his general condition improved and was discharged. Subsequently, gastric cancer surgery was performed and the patient was discharged without postoperative complications. Hence, amoebic colitis should be listed as a differential diagnosis, and a colonoscopic biopsy should be performed when colitis occurs during chemotherapy for cancer.

Co-infection of HIV and tropical infectious agents that affect the nervous system.

Tropical infections refer to a group of diseases usually located in regions with a warm climate, particularly affecting developing countries, partly because of the conditions that allow them to thrive. However, due to the increased international travel, infectious agents that were previously limited to tropical regions pose an increasing threat to populations at risk for opportunistic infection (OI), especially those infected with the HIV. Tropical infections can facilitate HIV transmission and accelerate the progression of asymptomatic HIV infection to AIDS. Some have the potential to alter the epidemiology, natural history, and/or response to treatment of the other. The introduction of highly active antiretroviral therapy has provided a huge benefit for the vast majority of patients infected with the HIV, by allowing the immune system to recover, improving the clinical and radiological results and reducing the number of OI. On the other hand, some patients have developed various disorders of immune reconstitution, resulting in either hyper-immune inflammatory response to an exogenous antigen or autoimmunity. A significant proportion of these cases have been reported in immigrants from tropical countries to high-income countries, therefore awareness of these phenomena is needed since clinical presentations are often atypical and pose diagnostic challenges. This article reviews some of the key diagnostic aspects of tropical infections associated with HIV infection.

Acanthamoeba meningoencephalitis in an immunocompetent patient: an autopsy case report.

Chronic granulomatous CNS infections may be caused by tuberculosis, fungi and rarely by free-living amoeba, especially in immunocompromised individuals. We report a rare, fatal case of granulomatous amoebic encephalitis in an immunocompetent patient mimicking CNS tuberculosis, and review the imageological features and diagnostic tests.

The public health threat from Balamuthia mandrillaris in the southern United States.

Balamuthia mandrillaris, formerly known as leptomyxid ameba, is an opportunistic, free-living ameba, related to Acanthamoeba that can cause skin lesions and granulomatous amebic encephalitis in individuals with compromised or competent immune systems. In order to make recommendations for early diagnosis, management, and prevention of typically fatal Balamuthia amebic encephalitis (BAE), this review described and analyzed laboratory-confirmed US cases of BAE for any consistent behavioral, demographic, environmental, ethnic, iatrogenic, occupational, recreational, or regional exposure factors over the study period, 1980-2010. The ages of all case-patients were stratified by age and gender and compared for statistically significant differences by two-tailed, unpaired t-tests. Potential risk factors were also stratified by age and gender, described, and compared by proportions and rates. The results of this study demonstrated that BAE occurred sporadically in patients of all ages in both immunosuppressed and immunocompetent patients. In addition, BAE exhibited only a few consistent predisposing factors that included male gender, exposure in a southern tier US state, and Hispanic ethnicity. Clinicians should suspect BAE in refractory cases of meningoencephalitis initially managed as aseptic or bacterial infections, especially in patients predisposed to BAE; confirm the diagnosis by immunodiagnostics, brain or skin biopsies, and institute conventional and, possibly, experimental, antiprotozoal therapy immediately. Brain dead victims of BAE are not suitable organ donors and have transmitted fatal BAE to organ transplant recipients.

Causality in acute encephalitis: defining aetiologies.

Defining the causal relationship between a microbe and encephalitis is complex. Over 100 different infectious agents may cause encephalitis, often as one of the rarer manifestations of infection. The gold-standard techniques to detect causative infectious agents in encephalitis in life depend on the study of brain biopsy material; however, in most cases this is not possible. We present the UK perspective on aetiological case definitions for acute encephalitis and extend them to include immune-mediated causes. Expert opinion was primarily used and was supplemented by literature-based methods. Wide usage of these definitions will facilitate comparison between studies and result in a better understanding of the causes of this devastating condition. They provide a framework for regular review and updating as the knowledge base increases both clinically and through improvements in diagnostic methods. The importance of new and emerging pathogens as causes of encephalitis can be assessed against the principles laid out here.

[The protozoan-infected brain in alcohol abusers].

The paper gives the studying the brain in 57 male patients with different types of ethanol intoxication and in 14 control group subjects. The material has been examined by a complex of histological, histochemical, and morphometric studies. The different regions of the brains from those who have died and had signs of alcoholic intoxication exhibit large microorganisms that belong to protozoa, as judged from their structure are identified. They are most commonly oval in shape. The peripheral portions of the parasites' bodies are light and homogeneous and the middle ones are muddy and granular. Their cytoplasm frequently displays vacuoles and inclusions that most often looked like basophilic acicular crystals. One or two nuclei that have large hyperchromic nucleoli are located in the center of the described microorganisms or eccentrically. They are encapsulated in a number of cases. The signs of mitotic division can be seen in individual parasites. Some of them die and are prone to petrification. All these signs allow the described protozoa to be assigned to amoebas.