Search

Intestinal protozoan parasites are responsible for diarrheal diseases causing significant morbidity and mortality. Entamoeba histolytica is the principle protozoan parasite associated with diarrheal infections. The infection is often associated with inaccessibility to clean drinking water and poor sanitary conditions in low- and middle-income countries including India. A comprehensive systematic review was performed to evaluate a reliable nationwide estimate for prevalence and geographic distribution of amoebiasis in India and the complications associated with it.We used the PRISMA guidelines to perform a systematic review and meta-analysis of articles published between the year 2001-2020. Two English language databases PubMed and Web of Science were searched to achieve relevant studies.Initial searches resulted in 467 studies out of which 64 eligible articles involving data from 289,659 human subjects from 12 states and 4 union territories were included in the final analysis. Prevalence of amoebiasis ranged from 3-23% in asymptomatic population, 0.64-11% in symptomatic patients and 1-17.5% in HIV-infected patients. Highest prevalence was seen in Tamil Nadu, Andaman Nicobar Island and North East India. Extra intestinal invasion of Entamoeba histolytica leading to complications such as amoebic liver abscess, amoebic colitis, colonic perforation and ameboma were also reported. Such complications have the potential to increase healthcare burden and may prove to be fatal.Amoebiasis remains a significant public health issue in India responsible for diarrheal diseases causing significant morbidity and mortality. Entamoeba histolytica is the principle protozoan parasite associated with amoebiasis. Public health efforts should be directed towards its control and better diagnostic methods should be employed for distinguishing between pathogenic and non-pathogenic species of Entamoeba.

The epidemiological behaviour of the main extraintestinal complication due to E. histolytica (amoebic liver abscess, ALA) has been little explored in developing countries. Since Mexico meets the characteristics to be considered as endemic, the aim of this work was to analyze the national surveillance data (seven years) of ALA issued by the General Directorate of Epidemiology. An analysis of cases and incidence of ALA (2014-2020) was performed in the annual reports issued by the GDE in Mexico. Cases and incidence of ALA were classified by year, incidence, age group, sex and seasons. Geographical distribution map for the whole country of ALA was constructed. The cases and mean incidence of ALA did not shown significant variation during the study period. Of the total cases accumulated, Sonora, Sinaloa, Nayarit, Colima and Zacatecas states showed the most incidence by ALA. Male sex of 24-44 years old showed higher ALA cases. No temporal behaviour was identified between the ALA cases. In Mexico, the incidence of ALA remains unchanged, however, it should not be underestimated since the monitoring programs for the search for new cases have not yet been implemented mainly in endemic states. These results summarize the priority in the national ALA report.

Recurrence of amebic liver abscess (ALA), once considered unusual, is increasingly being reported, despite proper management. Realizing the endemicity of ALA in the study setup, this 2-year follow-up study was conducted to investigate the recurrent cases and study the associated factors. A total of 101 confirmed cases of ALA were followed up for a period of 2 years. Recurrent cases were studied for associated bacterial flora, presence of resistance genes (nim), level of matrix metalloproteinase 3 and MMP-9, and genotypes of Entamoeba histolytica and statistically compared with the nonrecurrent cases as controls. Recurrence rates of 8.9% (nine patients) were detected. The presence of Prevotella along with an increased level of MMP-9 in abscess fluid and large size of abscesses (11 × 10.8 cm) was found to be significantly associated with recurrence in ALA. Among the nine cases, the presence of nimE gene was detected in two (22.2%) patients. The genotyping of E. histolytica strains showed that in seven (77.7%) cases, the genotype of E. histolytica was the same in the primary and recurrent samples. This study reports a high rate of recurrence in the cases of ALA, hinting toward the gradual development of clinical resistance toward the commonly used drug. The presence of nim gene and Prevotella in abscess fluid along with increased MMP-9 levels and large abscess size could be important predictors of recurrent ALA.

Patients with amoebic liver abscess (ALA) may require percutaneous catheter drainage (PCD). Once the PCD output is substantially reduced or has ceased along with clinical recovery, residual collections on radiological evaluation may concern the treating physicians. The prevalence and significance of such collections is unknown, and the subsequent approach how to tackle them is unclear. Consecutive patients with one or more uncomplicated ALAs requiring drainage were prospectively enrolled from 3 hospitals and managed based on a standard approach. Catheter removal was attempted after the patients fulfilled all 4 of the following criteria: disappearance of abdominal pain, absence of fever for at least 48 h, an improving trend of TLC (documented on 2 consecutive reports), and catheter drain output of

We report a rare case of amebiasis associated with an intraabdominal abscess without colitis, an intestinal perforation, or other extraintestinal amebiasis. A patient was admitted with cirrhosis and a history of spontaneous bacterial peritonitis (SBP) and was found to have a high C-reactive protein (CRP) level. Dynamic CT and ultrasound echo findings showed an intraabdominal abscess. No intestinal lesions or extraintestinal lesions other than the intraabdominal abscess were observed. Blood cultures and puncture fluid cultures were negative for bacteria. However, microscopic examination of the puncture fluid showed a cystic form of amoeba, leading to a diagnosis of an amoeba abscess. The abscess disappeared after 10 days of oral treatment with metronidazole. When an abdominal abscess is seen in an immunocompromised patient such as a cirrhotic patient, amoeba infection should be considered as a possible diagnosis.

Entamoeba histolytica is an intestinal protozoan parasite of humans and is endemic in developing countries. E. histolytica has two low molecular weight protein tyrosine phosphatase (LMW-PTP) genes, EhLMW-PTP1 and EhLMW-PTP2, which are expressed in cultured trophozoites, clinical isolates, and cysts. The amino acid sequences of proteins EhLMW-PTP1 and EhLMW-PTP2 showed only one amino acid difference between them at position A85V, respectively. Both genes are expressed in cultured trophozoites, mainly EhLMW-PTP2, and in trophozoites recovered from amoebic liver abscess, the expression of EhLMW-PTP1 is downregulated. We cloned the two genes and purified the corresponding recombinant (rEhLMW-PTPs) proteins. Antibodies anti-rEhLMW-PTP2 showed that during red blood cells uptake by E. histolytica, the EhLMW-PTPs were found in the phagocytic cups based on analysis of fluorescence signals. On the other hand, rEhLMW-PTPs showed an optimum phosphatase activity at pH 6.0 with p-nitrophenyl phosphate as the substrate. They dephosphorylate phosphotyrosine and 3-O-methylfluorescein phosphate, but not phosphoserine or phosphothreonine, and the enzymatic activity is inhibited by orthovanadate. rEhLMW-PTP1 and rEhLMW-PTP2 exhibited optimum temperatures of activities at 60 °C and 58 °C, respectively, with high thermal stability at 50 °C. Also, the rEhLMW-PTPs showed high specific activities and specific km value with pNPP or OMFP as the substrates at the physiological temperature (37 °C).

A man in his 60s visited a clinic with chief complaints of a fever and general malaise. Suspecting a liver abscess in the left lobe with infiltration into the subcutaneous fat tissue under the rectus abdominis muscle based on computed tomography findings, we performed fine-needle aspiration. An amoebic liver abscess was diagnosed. Remission was achieved by the oral administration of metronidazole alone without placement of a drainage tube. The results obtained in this case suggest that the first line of treatment should be a non-invasive approach with oral administration alone. Invasive intervention should then be considered depending on subsequent progress.

Conventional ultrasound is the main imaging modality in obstetrics for assessing the maternal and fetal status. Up to date, contrast-enhanced ultrasound (CEUS) has not found widespread use in gynecology and obstetrics, but recent studies demonstrate promising results. The aim of the present study is to assess safe and valuable application of CEUS during pregnancy to investigate non-obstetric conditions. Five pregnant patients on whom CEUS was performed between 2019 and 2020 were included in this retrospective single-center study. A total of six CEUS examinations were performed including one CEUS-guided biopsy (mean age: 31 years, mean weeks of pregnancy: 18 weeks). CEUS examinations were performed by a consultant radiologist (EFSUMB level 3). All included pregnant women safely underwent CEUS. Neither maternal nor fetal adverse effects were detected. CEUS critically helped in the diagnostic workup of a desmoid tumor of the abdominal wall, hepatic hemangioma, amebic hepatic abscess, uncomplicated renal cyst and post-inflammatory alteration of the renal cortex and for excluding active abdominal bleeding. In addition, CEUS-guided biopsy was performed to prevent intratumoral hemorrhage. Findings from CEUS prompted immediate treatment in two women, whereas in three women regular obstetric monitoring of the women could be conducted. Our results demonstrate safe and crucial application of off-label CEUS in pregnant women to assess different non-obstetric conditions allowing to prevent additional ionizing CT or application of (gadolinium-based) contrast agent in MRI. Hence, CEUS might add pivotal value for evaluating obstetric and non-obstetric conditions and thereby directing clinical management of pregnant women in the future.

Backgrounds/aims With the improvement of hygiene, the incidence of amebic liver abscess is decreasing in South Korea. On the other hand, there is little data on the status of amebic liver abscess compared to pyogenic liver abscess. Methods Patients with an amebic liver abscess, in whom Entamoeba histolytica (E. histolytica) IgG was positive, were identified retrospectively in a university hospital. The clinical, laboratory, and radiological characteristics of amebic liver abscess were compared with those of pyogenic liver abscess in the same period. Results Between March 2010 and October 2016, 413 patients with a liver abscess were identified. Among them, the serologic test for E. histolytica was performed in 209 patients. Fifteen (7.2%) were classified as an amebic liver abscess, and the remainder were diagnosed with a pyogenic liver abscess. The age, gender, white blood cell, and CRP was comparable between the two groups. Procalcitonin was lower in amebic liver abscess than the pyogenic one. On CT, peripheral rim enhancement was more frequent, but cluster signs were not observed in amebic liver abscess compared to pyogenic liver abscess. None of the patients with amebic liver abscess died. In contrast, the mortality of pyogenic liver abscess was 4.7%. Conclusions Amebic liver abscess should still be considered as one of the causes of liver abscess in Korea. It is difficult to discriminate an amebic liver abscess from a pyogenic liver abscess only according to the clinical, laboratory, and radiologic findings. Therefore, it is necessary to perform a serologic test for E. histolytica for a precise evaluation of liver abscess in a high-risk group.

Rab proteins constitute the largest group of small GTPases and act as molecular switches in a wide variety of cellular processes, including proliferation, cytoskeleton assembly, and membrane trafficking in all eukaryotic cells. Rab21 has been reported in several eukaryotic cells, and our results suggest that in Entamoeba histolytica, Rab21 is involved in the vesicular traffic associated with the Golgi apparatus, where its function appears to be important to maintain the structure of this organelle. In addition, proteins such as Rab1A and Sec24, identified in this work associated with EhRab21, participate in the traffic of COPII vesicles from the endoplasmic reticulum to the Golgi apparatus and are necessary to maintain the latter's structure in human cells. In addition, EhRab21 probably affects the lysosome biogenesis, as indicated by an increase in the number of lysosomes as a result of the increase in EhRab21 activity. The participation of EhRab21 in the pathogenesis of amebiasis was verified on the amoebic liver abscess formation model using hamsters (Mesocricetus auratus), in which the overexpression of EhRab21Q64L (positive dominant mutant protein) decreased the number of liver abscesses formed.

Entamoeba histolytica is a protozoan-pathogen-causing amoebic liver abscess (ALA). After amoeba establishment in the liver, it causes abundant infiltrate of neutrophils. Liver tissue damage by neutrophils results in part from anti-amoebic oxidative intermediates, including reactive oxygen species (ROS), reactive nitrogen species (RNS), and hypochlorous acid (HOCl), derived from the myeloperoxidase (MPO) enzyme. Ascorbic acid (ASC) is an antioxidant that acts as a scavenger for ROS and NOS-derived free radicals. No previous information regarding the effect of ASC concerning the participation of MPO in an experimental model of ALA in hamsters has been reported. Thus, the aim of the present work was to analyze the effect of ASC on acute ALA development and to measure the activity and gene expression of the MPO enzyme. Hamsters were treated with ASC (800 mg/kg) and then intrahepatically inoculated with E. histolytica trophozoites. Animals were sacrificed at 3, 6, and 12 h post-inoculation (p.i.), and liver samples were collected. The percentage of lesions, amoeba in situ count, MPO activity, and mpo gene expression were ascertained. Compared to ALA hamsters without ASC treatment as the control group (CT), the ALA group treated with ASC had a significant decrease in liver lesions (all p.i. hours) and viable amoeba count (12 h p.i.) and an increase in MPO activity (12 h p.i.) and mpo gene expression (6 h/12 h p.i.). These data suggest that ASC ameliorated liver damage caused by oxidizing products via modulation of mpo expression and activity.

Entamoeba histolytica is a protozoan parasite that causes amoebic dysentery and amoebic liver abscess in humans, affecting millions of people worldwide. This pathogen possesses a two-stage life cycle consisting of an environmentally stable cyst and a pathogenic amoeboid trophozoite. As cysts can be ingested from contaminated food and water, this parasite is prevalent in underdeveloped countries and poses a significant health burden. Until recently there was no reliable method for inducing stage conversion in E. histolytica in vitro. As such, the reptilian pathogen, Entamoeba invadens, has long-served as a surrogate. Much remains unclear about stage conversion in these parasites and current treatments for amoebiasis are lacking, as they cause severe side effects. Therefore, new therapeutic strategies are needed. The genomes of these parasites remain enigmatic as approximately 54% of E. histolytica genes and 66% of E. invadens genes are annotated as hypothetical proteins. In this study, we characterized two hypothetical proteins in the Entamoeba species, EIN_059080, in E. invadens, and its homolog, EHI_056700, in the human pathogen, E. histolytica. EHI_056700 has no homolog in the human host. We used an RNAi-based silencing system to reduce expression of these genes in E. invadens and E. histolytica trophozoites. Loss of EIN_059080 resulted in a decreased rate of encystation and an increased rate of erythrophagocytosis, an important virulence function. Additionally, mutant parasites were more susceptible to oxidative stress. Similarly, loss of EHI_056700 in E. histolytica trophozoites resulted in increased susceptibility to oxidative stress and glucose deprivation, but not to nitrosative stress. Unlike the E. invadens mutants, E. histolytica parasites with decreased reduced expression of EHI_056700 exhibited a decreased rate of erythrophagocytosis of and adhesion to host cells. Taken together, these data suggest that these hypothetical proteins play a role in stage conversion, virulence, and the response to stress in the Entamoebae. Since parasites with reduced expression of EHI_056700 show decreased virulence functions and increased susceptibility to physiologically relevant stressors, EHI_056700 may represent a possible therapeutic target for the treatment of amoebiasis.

Background Amoebiasis is caused by the protozoan Entamoeba histolytica, which is a rare infectious disease in developed countries. If the trophozoites enter the blood, it can spread through the body, such as brain, and lungs. Cases of simultaneous infection of multiple organs are extremely rare. Case presentation Here we report a case of simultaneous infection of amoeba in pulmonary pleura, urinary system and central nervous system. Although the patient received anti amoeba treatment, the prognosis of the patient was poor. Conclusions In this patient, multiple extraintestinal amebic infections in the absence of clinically confirmed intestinal amebiasis or amebic liver abscess are rare and pose diagnostic challenges. The disseminated amebiasis has significantly increased the mortality. Early diagnosis and appropriate treatment may reduce the mortality of disseminated amebiasis.

Although rare in the developed world, amebiasis continues to be a leading cause of diarrhea and illness in developing nations with crowding, poor sanitation, and lack of clean water supply. Recent immigrants or travelers returning from endemic regions after a prolonged stay are at high risk of developing amebiasis. A high index of suspicion for amebiasis should be maintained for other high-risk groups like men having sex with men, people with AIDS/HIV, immunocompromised hosts, residents of mental health facility or group homes. Clinical presentation of intestinal amebiasis varies from diarrhea to colitis and dysentery. Amebic liver abscess (ALA) is the most common form of extraintestinal amebiasis. Various diagnostic tools are available and when amebiasis is suspected, a combination of stool tests and serology should be sent to maximize the yield of testing. Treatment with an amebicidal drug such as metronidazole/tinidazole and a luminal cysticidal agent such as paromomycin for clinical disease is indicated. However, for asymptomatic disease treatment with a luminal cysticidal agent to decrease chances of invasive disease and transmission is recommended.

Background Amoebiasis is a parasitic disease caused by Entamoeba histolytica, which affects people living in low- and middle-income countries and has intestinal and extraintestinal manifestations. To date, knowledge on coronavirus disease 2019 (COVID-19) coinfection with enteric parasites is limited, and E. histolytica coinfection has not been previously described. Here we present the case of a patient with COVID-19 who, during hospitalisation, presented a clinical picture consistent with an amoebic liver abscess (ALA). Case presentation A 54-year-old man, admitted as a suspected case of COVID-19, presented to our hospital with dyspnoea, malaise, fever and hypoxaemia. A nasopharyngeal swab was positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by reverse-transcription polymerase chain reaction. After 7 days, he developed diarrhoea, choluria and dysentery. An abdominal ultrasound showed a lesion compatible with a liver abscess; stool examination revealed E. histolytica trophozoites, and additional serology for E. histolytica was positive. After 12 days of treatment with metronidazole, ceftazidime and nitazoxanide, the patient reported acute abdominal pain, and an ultrasound examination revealed free liquid in the abdominal cavity. An emergency exploratory laparotomy was performed, finding 3000 mL of a thick fluid described as “anchovy paste”. Computed tomography scan revealed a second abscess. He ended up receiving 21 days of antibiotic treatment and was discharged with satisfactory improvement. Conclusion Here we present, to the best of our knowledge, the first report of ALA and COVID-19 co-presenting. Based on their pathophysiological similarities, coinfection with SARS-CoV-2 and E. histolytica could change the patient’s clinical course; however, larger studies are needed to fully understand the interaction between these pathogens.

Amebic liver abscess is the most common type of liver abscess on a worldwide basis, with caudate lobe being a relatively uncommon location for its occurrence. Abscess in caudate lobe of liver is often considered a challenging location for image-guided percutaneous drainage due to its difficult-to-access location along with close relationship with major vessels at porta hepatis.This study aims to demonstrate safety and efficacy of percutaneous drainage for caudate lobe amebic abscess.In this retrospective study, hospital database was electronically searched for patients having caudate lobe amebic abscess that underwent percutaneous catheter drainage/needle aspiration (PCD/PNA) between January 2016 and January 2021. The etiology, risk factors, microbiology, complications, different approaches for PCD/PNA, and their outcome were studied and reported.Of 30 patients having caudate lobe amebic abscess treated with PCD/PNA, solitary caudate lobe abscess was seen in 29, whereas one patient had more than one abscesses in caudate lobe. Contained and free intraperitoneal rupture of the abscess were seen in 9 (30%) and one patient, respectively. Ten (32%) patients had associated vascular thrombosis, while 2 patients were found to have abscess-biliary communication. Twenty-six (86.7%) patients were treated with PCD, while remaining 4 (13.3%) with PNA. On Univariate analysis, factors such as volume, multilocularity, and contained rupture of the abscess were found to be significantly increasing the duration of percutaneous drainage (PCD), while only multilocularity (p value 0.007) continued to show statistical significance on Multivariate analysis. Venous thrombosis and duration of catheter drainage were the two factors found to have significant influence on the length of hospital stay on Univariate as well as Multivariate analysis (p value 0.05 and 0.001, respectively). The rates of catheter manipulation were also significantly higher in patients with abscess showing complex internal configuration (heteroechoic contents and/or multilocularity). Technical and clinical success rates of 100% and 96.7% were achieved through percutaneous interventions (PCD/PNA), despite the complex location of abscesses and associated complications, with no incidence of vascular injury.Liver abscess in caudate lobe can be accessed by different routes for percutaneous drainage, despite being surrounded by large vessels and its deep location, without major complications. Thus, PCD/PNA may be considered as a first-line therapy for the management of caudate lobe amebic abscesses in adjunct to medical therapy.

Tuberculosis of the stomach is quite rare, both as a primary or secondary infection. It has varied presentation ranging from non-specific abdominal pain and constitutional symptoms to hematemesis, gastric outlet obstruction and pyrexia of unknown origin. Here, we report a rare, interesting case of locally advanced gastric tuberculosis, which morphologically mimicked liver abscess initially in a young, immunocompetent patient presenting with fever and abdominal pain. The disease was diagnosed by GeneXpert MTB/RIF assay, and responded well to antituberculosis medication without surgery. Clinicians must bear in mind that, even in the absence of immunodeficiency, as in this case, tuberculosis can involve any site in the gastrointestinal tract and may present with a variety of presentation and infiltrating adjacent organ that might be mistaken as malignancy. This is first case report of gastric tuberculosis, which is locally advanced with adjacent liver infiltration initially thought to be left lobe liver abscess.

Introduction Liver abscesses are mainly caused by parasitic or bacterial infection and are an important cause of hospitalization in low-middle income countries (LMIC). The pathophysiology of abscesses is different depending on the etiology and requires different strategies for diagnosis and management. This paper discusses pathophysiology and epidemiology, the current diagnostic approach and its limitations and management of liver abscess in low resource settings. Sources of data We searched PubMed for relevant reviews by typing the following keywords: ‘amoebic liver abscess’ and ‘pyogenic liver abscess’. Areas of agreement Amoebic liver abscess can be treated medically while pyogenic liver abscess usually needs to be percutaneously drained and treated with effective antibiotics. Areas of controversy In an LMIC setting, where misuse of antibiotics is a recognized issue, liver abscesses are a therapeutic conundrum, leaving little choices for treatment for physicians in low capacity settings. Growing points As antimicrobial resistance awareness and antibiotic stewardship programs are put into place, liver abscess management will likely improve in LMICs provided that systematic adapted guidelines are established and practiced. Areas timely for developing research The lack of a quick and reliable diagnostic strategy in the majority of LMIC makes selection of appropriate treatment challenging.

The role of metronidazole alone, percutaneous aspiration (PA), and percutaneous catheter drainage (PCD) in the treatment of uncomplicated amebic liver abscess (ALA) is still unclear. This systematic review and meta-analysis evaluated the available evidences with regard to treatment modalities in such patients. The database was searched for relevant randomized controlled trials (RCTs) published until May 2019. All studies were assessed for risk of bias. The relevant data were pooled in a random or fixed-effect model to calculate the mean difference (MD) or relative risks. After the detailed screening, 570 patients from 10 RCTs comparing metronidazole alone with metronidazole + PA were included. Most studies had uncertain risk of biases. Days to resolution of abdominal pain (MD − 1.59, 95% confidence interval [CI] − 2.77, − 0.42, I2 = 89%) and tenderness (MD − 1.76, 95% CI − 2.93, − 0.58, I2 = 72%) were significantly shorter in the metronidazole + PA group. There was no significant difference in relation to the resolution of fever, abscess size, and hospital stay. The beneficial effects of PA were seen with medium-to-large (> 5 cm) ALA and not with small (

Amoebic liver abscess (ALA) is a common clinical problem in tropical countries related to poor sanitation. The epidemiology and clinical presentation of ALA in Fiji has not been previously described. It is unclear whether percutaneous aspiration (PA) or percutaneous catheter drainage (PCD) has better outcomes. The aims were to describe the epidemiology and clinical presentation of ALA in Fiji and to compare the outcomes of PA and PCD for treatment of ALA. A retrospective case note review of patients treated with either PA or PCD between 2010 and 2015 was performed. Indications for intervention were ALA > 5 cm, ALA in the left lateral lobe, risk of imminent rupture and failure to respond to medical treatment. There were 262 patients, 90% were male, 92.9% I-Taukei ethnicity and 86.2% regular recreational kava drinkers. Most presented with upper abdominal pain and fevers. The majority (90.3%) had a single abscess with 87.8% being in the right lobe. 174 (66.4%) had LA and 88 (33.6%) had PCD. There was an unintended selection bias for PA in abscess with a volume of

The role of toddy (palm wine) as an independent risk factor for amoebic liver abscess (ALA) is not clear. In a cross-sectional study, the clinico-demographic profiles of inpatients with ALA were examined. Microscopy examination of toddy (n = 43) samples was performed. A total of 198 patients with ALA were enrolled, most of whom were: admitted during the May–August months (48%); chronic alcoholic (85% [70% toddy]); malnourished (85%); and of low socioeconomic status (88%). Clinical and laboratory parameters were comparable between toddy and distilled alcohol drinkers. None of the toddy samples revealed presence of cysts and trophozoites of Entamoeba histolytica.

Background Despite similarities in morphology, gene and protein profiles, Entamoeba histolytica and E. moshkovskii show profound differences in pathogenicity. Entamoeba histolytica infection might result in amoebic dysentery and liver abscess, while E. moshkovskii causes only mild diarrhea. Extensive studies focus on roles of host immune responses to the pathogenic E. histolytica; however, evidence for E. moshkovskii remains scarce. Methods To study differences in host-antibody response profiles between E. histolytica and E. moshkovskii, mice were immunized intraperitoneally with different sets of Entamoeba trophozoites as single species, mixed species and combinations. Results Mice prime-immunized with E. histolytica and E. moshkovskii combination, followed by individual species, exhibited higher IgG level than the single species immunization. Mice immunized with E. moshkovskii induced significantly higher levels and long-lasting antibody responses than those challenged with E. histolytica alone. Interestingly, E. histolytica-specific anti-sera promoted the cytopathic ability of E. histolytica toward Chinese hamster ovarian (CHO) cells, but showed no effect on cell adhesion. There was no significant effect of immunized sera on cytopathic activity and adhesion of E. moshkovskii toward both CHO and human epithelial human colonic (Caco-2) cell lines. Monoclonal-antibody (mAb) characterization demonstrated that 89% of E. histolytica-specific mAbs produced from mice targeted cytoplasmic and cytoskeletal proteins, whereas 73% of E. moshkovskii-specific mAbs targeted plasma membrane proteins. Conclusions The present findings suggest that infection with mixed Entamoeba species or E. moshkovskii effectively induces an antibody response in mice. It also sheds light on roles of host antibody response in the pathogenic difference of E. histolytica and E. moshkovskii trophozoites, and cell surface protein modifications of the amoebic parasites to escape from host immune system.

Amoebiasis is a protozoan disease caused by Entamoeba histolytica, and presents a geographic distribution of worldwide amplitude, high incidence, sometimes accompanied by severe clinical manifestations such as amoebic colitis and Amoebic Liver Abscess (ALA), remaining as a public health problem in developing countries. Entamoeba dispar is another species of amoeba that infects approximately 12% of the world's population, and it has previously been classified as noninvasive. However, E. dispar has already been isolated from patients with symptomatic non-dysenteric colitis, as well as its DNA sequences were detected and genotyped in samples from patients with dysenteric colitis, and patients with ALA, suggesting that this species could also be involved in the development of lesions in the large intestine and liver of human beings. In this context, this study aims to evaluate the ability of isolated strains of Entamoeba dispar in South America to cause liver damage, and to better characterize histopathological findings in 3, 8, 12 and 16 days after infection (DAI). Firstly, we assessed whether trophozoites from MCR, ACFN, ICS, ADO and VEJ E. dispar strains, and EGG Entamoeba histolytica strain differed in their in vitro phagocytosis ability, being related to greater ability to phagocyte with greater virulence. Then, we investigate and characterize histopathological changes present in the liver of mice induced by different strains of E. dispar. Our results demonstrated that trophozoites from E. dispar strains are capable of phagocyting human erythrocytes, but in lower amounts than Entamoeba histolytica. In addition, we described and characterized the lesions in different periods after infection by different E. dispar strains, and identified ACFN as the most pathogenic strain, followed by MCR. The large areas of necrosis produced by the ACFN strain as the eighth DAI, which also show high parasitism, led to 100% mortality. On the other hand, the ICS, ADO and VEJ strains did not produce mortality, and this was correlated with the presence of well-developed chronic granulomatous inflammation, necrosis absorption throughout the infection, and regeneration of the liver parenchyma. The greater pathogenicity of the ACFN strain strongly suggests that this strain could be producing higher levels of virulence factors. As the experimental infection, the heterogeneity of biological behavior of different Entamoeba dispar strains could be involved in the development of undiagnosed human clinical conditions.

Definitive diagnosis of amoebic liver abscess is challenging owing to the unavailability of sensitive commercial point-of-care molecular tests. The primary aim of our prospective diagnostic study was to compare available laboratory methods for the diagnosis of Entamoeba histolytica in clinical samples with loop-mediated isothermal amplification. We compared deoxyribonucleic acid (DNA) analysis methods, namely, loop-mediated isothermal amplification and reverse transcriptase polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA) using pus, stool and blood samples from 200 patients with clinical and radiological diagnosis of amoebic liver abscess. Loop-mediated isothermal amplification had significantly higher sensitivity (88%) as compared to reverse transcriptase polymerase chain reaction (64%) and excellent specificity (100%).

Purpose To identify different morphological types of amebic liver abscess (ALA) based on CT findings and to assess whether they have different clinical features. Method CT images of 112 symptomatic patients with ALA were analyzed to identify the imaging features distinctive of each morphological type. The following CT findings were investigated: the presence of abscess wall, rim enhancement, edge characteristic, septa, intermediate density zone, and peripheral hypodensity. Abscesses from each type were further evaluated for their clinical presentations, laboratory findings and outcomes. Results We identified three types of ALAs: type I, II and III. Type I abscesses (66%) were characterized by absent or incomplete walls, ragged edges and peripheral septa; their edges exhibited irregular and interrupted enhancement. Type II (28%) had a complete wall characterized by rim enhancement and peripheral hypodense halo. Type III (6%) demonstrated a wall but without enhancement. Clinically, type I abscesses presented acutely with severe disease. They had significantly deranged laboratory parameters, higher incidence of rupture and higher rate of inpatient or intensive care unit admission. The severity of the disease prompted immediate percutaneous drainage in most type I abscesses (81%). Two of them died from multiple organ failure. The type II or III abscesses, on the other hand, had delayed presentations with mild to moderate disease, with near normal laboratory findings. Conclusion ALAs have three different CT morphological types, with different clinical and laboratory features. Percutaneous drainage is indicated in most of type I abscesses.

BACKGROUND Liver abscess (LA), a common problem in children in the tropics, is believed to be mostly pyogenic (PLA), sometimes amebic (ALA). We aimed to analyze the clinical profile, etiology, risk factors for complications, management and outcomes of LA in children. METHODS The details of 81 children with LA managed in a tertiary set up over a period of 3 years were analyzed. A comparison of different parameters was performed with respect to etiology and complications. RESULTS ALA, PLA and mixed infection LA were diagnosed in 40 (49.4%), 32 (39.5%) and 9 (11.1%) children. The triad of fever, hepatomegaly and right upper quadrant tenderness was seen in 65 (80.2%). Coagulopathy was observed in 60 (77%) and jaundice in 12 (14.8%). Majority (71.6%) had a single LA in the right lobe (69%). Conservative, percutaneous needle aspiration, percutaneous catheter drainage and surgical drainage were done in 11.1%, 3.7%, 82.7% and 2.5%, respectively. Forty-three (53.1%) had complicated LA with rupture in 55.8% and vascular thrombosis in 16.2%. Children with complicated LA had higher alanine transaminase, prolonged prothrombin time/international normalized ratio, low serum protein and albumin levels (P < 0.05). Median duration of follow-up was 2 months and mean time to resolution of LA was 48.5 ± 18 days. CONCLUSIONS ALA is the commonest cause of pediatric LA in endemic regions and is difficult to differentiate from PLA clinically. Percutaneous catheter drainage is safe and effective modality for the management of LA in children. A higher alanine transaminase, prolonged prothrombin time/international normalized ratio and low serum albumin levels (

Entamoeba histolytica is an invasive enteric protozoan, whose infections are associated to high morbidity and mortality rates. However, only less than 10% of infected patients develop invasive amebiasis. The ability of E. histolytica to adapt to the intestinal microenvironment could be determinant in triggering pathogenic behavior. Indeed, during chronic inflammation, the vagus nerve limits the immune response through the anti-inflammatory reflex, which includes acetylcholine (ACh) as one of the predominant neurotransmitters at the infection site. Consequently, the response of E. histolytica trophozoites to ACh could be implicated in the establishment of invasive disease. The aim of this study was to evaluate the effect of ACh on E. histolytica virulence. Methods include binding detection of ACh to plasma membrane, quantification of the relative expression of virulence factors by RT-PCR and western blot, evaluation of the effect of ACh in different cellular processes related to E. histolytica pathogenesis, and assessment of the capability of E. histolytica to migrate and form hepatic abscesses in hamsters. Results demonstrated that E. histolytica trophozoites bind ACh on their membrane and show a clear increase of the expression of virulence factors, that were upregulated upon stimulation with the neurotransmitter. ACh treatment increased the expression of L220, Gal/GalNAc lectin heavy subunit (170 kDa), amebapore C, cysteine proteinase 2 (ehcp-a2), and cysteine proteinase 5 (ehcp-a5). Moreover, erythrophagocytosis, cytotoxicity, and actin cytoskeleton remodeling were augmented after ACh treatment. Likewise, by assessing the formation of amebic liver abscess, we found that stimulated trophozoites to develop greater hamster hepatic lesions with multiple granulomas. In conclusion, ACh enhanced parasite pathogenicity by upregulating diverse virulence factors, thereby contributing to disease severity, and could be linked to the establishment of invasive amebiasis.

Background Infection with Entamoeba histolytica and associated complications are relatively rare in developed countries. The overall low prevalence in the Western world as well as the possibly prolonged latency period between infection with the causing pathogen and onset of clinical symptoms may delay diagnosis of and adequate treatment for amoebiasis. Amoebic liver abscess (ALA) is the most common extraintestinal manifestation of invasive amoebiasis. Pregnancy has been described as a risk factor for development of invasive amoebiasis and management of these patients is especially complex. Case presentation A 30-year-old Caucasian woman in early pregnancy presented to our emergency department with abdominal pain alongside elevated inflammatory markers and liver function tests. Travel history revealed multiple journeys to tropic and subtropic regions during the past decade and a prolonged episode of intermittently bloody diarrhea during a five month stay in Indonesia seven years prior to admission. Sonographic and magnetic resonance imaging revealed a 5 × 4 cm hepatic abscess. After ultrasound-guided transcutaneous liver drainage, both abscess fluids and blood cultures showed neither bacterial growth nor microscopic signs of parasitic disease. Serological testing confirmed an infection with Entamoeba histolytica, which was treated with metronidazole, followed by eradication therapy with paromomycin. Subsequent clinical, laboratory and imaging follow-up exams showed regression of the ALA. In addition, the pregnancy completed without complications and a healthy baby boy was born 7 months after termination of treatment. Conclusions This case of invasive amoebiasis in early pregnancy outside of endemic regions and several years after exposure demonstrates the importance of broad differential diagnostics in the context of liver abscesses. The complex interdisciplinary decisions regarding the choice of imaging techniques as well as interventional and antibiotic therapy in the context of pregnancy are discussed. Furthermore, we present possible explanations for pregnancy as a risk factor for an invasive course of amoebiasis.

Linearolactone (

Objective: Amebic liver abscess (ALA) is endemic to many areas of the world. In this study we sought to investigate the epidemiology, presentation, laboratory tests and imaging characteristics related to ALA in Oman and ultimately determine whether ALA is native to Oman or is it imported from abroad. Methods: This case series study was conducted at Royal Hospital Muscat, Oman. Patient data was extracted from the Royal Hospital patient database and included patients older than 13 years of age, discharged with the discharge diagnosis of ALA from January 2013 to December 2017. Results: 22 patients were included in the study. The results showed 18 Omani patients and 4 expatriates. Only two Omanis had history of travel abroad. 15 patients were male and 7 females. The average age was 45.2. The most common presentation was abdominal pain seen in 17 patients. Fever was seen in 13 patients. Alanine transferase was found to be elevated in 13 patients. 90% of patients had no symptomatic infections prior to developing ALA. Conclusion: The data suggests that ALA is endemic to Oman given the higher number of local patients and the lack of travel abroad in this population. As the number of treated ALA patients is rather small, it can be concluded that the occurrence of ALA is much lower in Oman as compared to other endemic areas. The majority of patients had no prior symptomatic infections and thus a method of control would be to screen and prevent amebic spread. Keywords: Amebic liver abscess, Amebiasis, liver abscess, Entamoeba histolytica, Royal Hospital, Oman

Entamoeba histolytica is an intestinal parasite that causes dysentery and amebic liver abscess. E. histolytica has the capability to invade host tissue by union of virulence factor Gal/GalNAc lectin; this molecule induces an adherence-inhibitory antibody response as well as to protect against amebic liver abscess (ALA). The present work showed the effect of the immunization with PEΔIII-LC3-KDEL3 recombinant protein. In vitro, this candidate vaccine inhibited adherence of E. histolytica trophozoites to HepG2 cell monolayer, avoiding the cytolysis, and in a hamster model, we observed a vaccine-induced protection against the damage to tissue liver and the inhibition of uncontrolled inflammation. PEΔIII-LC3-KDEL3 reduced the expression of TNF-α, IL-1β, and NF-κB in all immunized groups at 4- and 7-day postinfection. The levels of IL-10, FOXP3, and IFN-γ were elevated at 7 days. The immunohistochemistry assay confirmed this result, revealing an elevated quantity of +IFN-γ cells in the liver tissue. ALA formation in hamsters immunized was minimal, and few trophozoites were identified. Hence, immunization with PEΔIII-LC3-KDEL3 herein prevented invasive amebiasis, avoided an acute proinflammatory response, and activated a protective response within a short time. Finally, this recombinant protein induced an increase of serum IgG.

Independent evaluations of XEh Rapid(®), an IgG4-based rapid dipstick test, were performed to assess its diagnostic performance to detect amebic liver abscess (ALA) using 405 samples at seven laboratories in four countries. The test showed high diagnostic specificity (97–100%) when tested with samples from healthy individuals (n = 100) and patients with other diseases (n = 151). The diagnostic sensitivity was tested with a total of 154 samples, and the results were variable. It was high in three laboratories (89–94%), and moderate (72%) and low (38%) in two other laboratories. Challenges and issues faced in the evaluation process are discussed. Nevertheless, XEh Rapid is promising to be developed into a point-of-care test in particular for resource-limited settings, and thus merits further confirmation of its diagnostic sensitivity.

Amoebic liver abscess (ALA) is regularly seen in travelers or immigrants from tropical countries. The diagnosis relies on liver imaging that is not specific and on the detection of anti-Entamoeba histolytica antibodies, which cannot distinguish an acute from a former infection. We tested whether E. histolytica DNA detection in serum can improve the diagnosis of ALA. We retrospectively tested available serum samples taken from patients with ALA and non-ALA space-occupying lesions of the liver between 1 January 2010 and 30 November 2019. The quantitative PCR (qPCR) assay tested specifically amplifies a 99-bp fragment of the small-subunit rRNA gene of E. histolytica. We analyzed 76 samples (19 ALA and 57 non-ALA samples) collected from 76 patients within 6 days before and after the antiamoebic treatment. Serum qPCR results were positive for 17 of 19 ALA patients and for none of the control patients (sensitivity and specificity were 89.5% and 100%, respectively). In parallel, the sensitivity and specificity of anti-E. histolytica antibody detection were 100% and 89.5%, respectively. The two false-negative qPCR results may be explained by ongoing metronidazole treatment or a possible persistent seropositivity that was not caused by the current liver abscess. Additionally, of 12 abscess pus aspirates (5 from ALA and 7 from non-ALA samples) tested, 5 were qPCR positive and 7 were qPCR negative, with concordant results in serum. This study demonstrates that cell-free circulating E. histolytica DNA can be detected in serum in ALA. This may assist in both positive diagnoses and treatment efficacy follow-up. The origin of this circulating DNA remains to be investigated.

Background Amebiasis is a rare condition in developed countries but epidemiologically growing. Clinical manifestation may range from asymptomatic to invasive disease, amoebic liver abscess being the most common manifestation. We report a peculiar case of left hepatic amoebic liver abscess in a patient without a well-known source of infection and presenting with left portal vein thrombosis. Case presentation Patient, working as longshoreman, presented with complaints of remittent-intermittent fever lasting from 2 weeks. Physical examination was normal. Blood tests showed mild anemia, neutrophilic leukocytosis and elevated inflammation markers. Chest x-rays was normal. Abdominal ultrasound showed multiple hypoechoic liver masses. CT-scan of abdomen showed enlarged left liver lobe due to the presence of large abscess cavity along with thrombosis of left portal vein. The indirect hemagglutination test for the detection of antibodies to Entamoeba histolytica (Eh) was positive. Ultrasound-guided percutaneous drainage revealed “anchovy sauce” pus. Metronidazole and a follow up imaging at 3 months showed resolution of abscess cavity. Conclusion This case shows that amoebic liver abscess is possible even in first world country patients without travel history. Left sided abscess and portal vein thrombosis are rare and hence reported.

Entamoeba histolytica infections are rare in developed countries such as Belgium. A 53-year-old female patient presented with 10 days of fever and mild persisting pain in the right hypochondriac despite 6 days of antibiotic therapy. The anamnesis further revealed that the patient was born in Colombia and visits her native country on a regular basis. An abdominal CT-scan demonstrated a large hepatic abscess of 10×8 cm. The diagnosis of Entamoeba histolytica- infection was confirmed with real-time PCR (RT-PCR) from the aspirated material of the abscess. Remarkably, a half year ago, this patient also presented to the gastro-enterology consultation with intermittent rectal bleeding, loose stools and abdominal discomfort. Rectosigmoidoscopy at that time showed sigmoiddiverticulosis and biopsies were taken. RT-PCR on this material was performed during this second episode and was positive for E. histolytica, confirming an episode of amoebic colitis a half year prior to the discovery of the liver abscess.

Amoebiasis, caused by Entamoeba histolytica, is one of the leading parasitic infections in the world. This study was aimed at profiling antigenic membrane proteins of a virulent variant of E. histolytica HM-1:IMSS. The membrane proteins were extracted using ProteoExtract® kit (Merck, Darmstadt, Germany) or conventional method, separated using OFFGEL 3100 fractionator (Agilent Technologies, Santa Clara, California), followed by SDS-PAGE and Western blot analysis. Selected antigenic membrane proteins were identified using LC-ESI-MS/MS. Subsequently, the proteins were classified according to their biological processes and predictions were made on membrane and membrane-associated proteins. When the proteins were probed with pooled sera from amoebic liver abscess (ALA) patients, 10 and 15 antigenic proteins with molecular weights 25 to 200 kDa were identified using the ProteoExtract® kit and conventional method, respectively. LC-ESI-MS/MS identified 13 antigenic proteins, and both extraction methods predicted six of them as membrane and membrane-associated proteins. The topmost biological processes which comprised of six proteins were involved in cellular processes.. These antigenic membrane proteins merit further investigations as potential candidates for vaccine studies.

A 78-year-old male, originally from China, was brought to the hospital for weakness, urinary incontinence, confusion, and poor oral intake. He was started on empiric antibiotics, which were narrowed when blood cultures produced gram-negative bacteremia speciating to Klebsiella pneumoniae, sensitive to ceftriaxone. Computed tomography scan of the abdomen and pelvis demonstrated a large cystic region with air-fluid level in the left lobe of the liver. Suspecting this to be the source of the patient’s bacteremia, the lesion was percutaneously drained and the fluid cultured, which also revealed ceftriaxone-sensitive Klebsiella pneumoniae. While a stool ova and parasite examination on the patient was negative, further workup was positive for Entamoeba histolytica antibody in the serum, detected via enzyme-linked immunosorbent assay and indicative of either current or past infection. This suggested possible prolonged subclinical infection with bacterial superinfection, especially given that Klebsiella pneumoniae is one of the most common organisms cultured from these abscesses. In patients with liver abscesses who immigrated from developing and/or endemic regions or have a relevant recent travel history, an underlying amoebic etiology of an abscess should be considered.

Pyogenic liver abscesses are classified by the bacteria that have caused the abscess because this guides treatment and can point to the underlying cause. The most common cause is biliary disease. The diagnosis is made by imaging. Treatment is a combination of antibiotics and percutaneous drainage. Amebic liver abscess is caused by extraintestinal spread of Entamoeba histolytica. E histolytica is spread by fecal-oral transmission and typically colonizes the gastrointestinal tract. It is diagnosed based on imaging and the mainstay of treatment is metronidazole. Only about 15% of cases require percutaneous drainage. The prognosis is good, with almost universal recovery.

Background Metronidazole (MNZ) has been clearly established as a medication for amebic liver abscess. In uncomplicated cases, surgical drainage should be avoided. We report a case of amebic liver abscess refractory to MNZ that was successfully treated using preoperative computed tomography (CT) and percutaneous and surgical drainage with intraoperative ultrasonography (IOUS). Case presentation A 53-year-old man with high-grade fever was diagnosed with a cystic lesion on his right hepatic lobe using CT. Percutaneous drainage was performed, and antibacterial drugs were administered. However, the infection and condition of the patient worsened. Entamoeba histolytica was detected from pus within the mediastinal cavity. Hence, the patient was diagnosed with amebic liver abscess. After the diagnosis was established, we administered MNZ for 10 days. Despite this, the patient’s physical condition did not improve. Blood tests suggested impending disseminated intravascular coagulation (DIC). We performed surgical intervention to drain the amebic liver abscess refractory to conservative treatment. During surgery, imaging information from preoperative CT and IOUS enabled us to recognize the anatomical structures and determine the incision lines of the hepatic capsule and hepatic tissue. The patient’s DIC immediately regressed after surgery. Unfortunately, malnutrition and disuse syndrome contributed to the patient’s long recovery period. He was discharged 137 days post-surgery. Conclusions We reported a case of amebic liver abscess refractory to conservative treatment. Surgical drainage with preoperative CT and IOUS allowed us to safely and effectively perform complex abscess decompression.

The main effector mechanisms of neutrophils are the release of neutrophil extracellular traps (NETs) and myeloperoxidase (MPO). In this work, we evaluated the role of NETs and the activity of MPO in the interactions of rodent neutrophils with amoebae and in amoebic liver abscess (ALA)-resistant and ALA-susceptible models. We showed with in vitro assays that mice produced greater amounts of NETs and MPO than did hamsters, and the elastase activity was high in both models. However, the inhibition of NETs and MPO promoted an increase in amoeba viability in the mice. The mouse ALAs showed a more profound presence of NETs and MPO than did the hamster ALAs. We concluded that both effector mechanisms were essential for the amoebic damage and could prevent the formation of ALAs in the resistant model.