Amoebic liver abscess: a neglected tropical disease

Vascular complications of amebic liver abscess - Computed tomography case series with review of the literature

Amebiasis is a parasitic infection with amebic liver abscess (ALA) being the most common extraintestinal manifestation. Common complications of ALA include rupture into the pleural, pericardial, or peritoneal cavity. Uncommonly, they can cause vascular complications such as thrombosis of the hepatic vein and inferior vena cava which may further extend to the right atrium or may embolize resulting in pulmonary thromboembolism. In this study, we report three patients with vascular complications in ALA. The presence of vascular pathology in ALAs should not be missed. With its detection and prompt treatment, the progression of vascular complications can be prevented.

Hepatic abscess caused by foreign body ingestion: A case report

Introduction

Liver abscess is a common clinical condition caused by bacterial, fungal or parasitic infections, usually due to immunosuppression. In contrast, secondary liver abscesses are caused by specific factors such as foreign bodies, tumours, or appendicitis.

Methods

We admitted a patient with secondary liver abscess and found an intrahepatic foreign body after interventional drainage. Initially, a foreign body of medical origin was suspected, but after a multidisciplinary consultation, it was determined to be caused by a foodborne foreign body. Laparoscopic surgery was then chosen as the treatment.

Result

The liver abscess was caused by an alimentary foreign body, and the intrahepatic foreign body was identified as a fish bone measuring approximately 2.5 cm in length.

Discussion

Upon diagnosing either primary or secondary liver abscess, aggressive treatment of the abscess focus is essential. However, in cases of secondary liver abscess, addressing and removing the underlying cause is necessary for complete resolution. For patients with a previously healthy liver, comprehensive history-taking is crucial, and imaging studies play a significant role in diagnosis and treatment. Clinicians and radiologists should be vigilant for the possibility of foreign bodies, tumours, or unexpected intra-abdominal inflammation, regardless of the patient's history. When dealing with food-borne foreign bodies, endoscopic intervention should be considered first, followed by laparoscopy, and as a last resort, open surgery.

Conclusion

The diagnosis and treatment of liver abscess in clinical practice require a complete medical history and thorough imaging examinations. Ultrasound, as the initial imaging modality, allows real-time and dynamic observation of lesions. It is essential for ultrasonologists to consider the possibility of foreign body-induced liver abscess when diagnosing patients with liver abscess.

Characterization of a model of liver regeneration: Role of hedgehog signaling in experimental hepatic amoebiasis

The development of amoebic liver abscess (ALA) leads to liver necrosis, accompanied by an exacerbated inflammatory response and the formation of multiple granulomas. Adequate management of the infection through the administration of treatment and the timely response of the organ to the damage allows the injury to heal with optimal regeneration without leaving scar tissue, which does not occur in other types of damage such as viral hepatitis that may conducts to fibrosis or cirrhosis. The Hedgehog signaling pathway (Hh) is crucial in the embryonic stage, while in adults it is usually reactivated in response to acute or chronic injuries, regeneration, and wound healing. In this work, we characterized Hh in experimental hepatic amoebiasis model, with the administration of treatment with metronidazole, as well as a pathway inhibitor (cyclopamine), through histological and immunohistochemical analyses including an ultrastructure analysis through transmission electron microscopy. The results showed an increase in the percentage of lesions obtained, a decrease in the presence of newly formed hepatocytes, a generalized inflammatory response, irregular distribution of type I collagen accompanied by the presence of fibroblast-type cells and a decrease in effector cells of this pathway. These results constitute the first evidence of the association of the activation of Hh with the liver regeneration process in experimental amebiasis.

Novel diagnostic approach for amoebic liver abscess using cell free (cf) DNA: a prospective study

BACKGROUND

Amoebic liver abscess (ALA) is commonly seen in tropical countries and diagnosis of ALA relies mainly on non-specific serological and imaging techniques as well as PCR from pus.

OBJECTIVE

This study evaluated the potential of using cell free DNA (cfDNA) from serum and urine for diagnosing ALA.

METHODS

We prospectively evaluated quantitative PCR (qPCR) for detection of cf DNA in serum and urine sample in all liver abscess patients. The samples were collected from patients reporting to emergency ward of Postgraduate Institute of Medical Education and Research, Chandigarh, India with symptoms suggestive of liver abscess. Real time PCR was done to detect cf DNA in serum and urine by targeting 99-bp unit of small subunit rRNA of Entamoeba histolytica and conventional PCR for pus.

RESULTS

A total 113 samples (serum and urine) and 100 pus samples were analysed. A total of 62 ALA patients were confirmed; with maximum 57 patients detected by qPCR for cfDNA in the serum, 55 patients by PCR on pus aspirate and 50 ALA patients by qPCR for cfDNA in urine sample. Therefore, the sensitivity of qPCR for detection of cf DNA in serum was 91.94% and for urine was 80.65%.

CONCLUSION

A total of 11.2% of ALA patients were diagnosed only through detection of E. histolytica cf DNA in their serum and urine. Detection of cfDNA from serum, urine of ALA has a potential role in future especially for developing countries as it is a rapid, sensitive and patient friendly diagnostic approach.

Amoebic colitis and liver abscess: A rare case of autochthonous invasive infection due to Entamoeba histolytica

We report an unusual and confirmed case of invasive amebiasis in a non-endemic area where the source of infection remains unknown. During her admission, the patient developed amebic colitis and extraintestinal liver abscess with a favorable outcome following the antiparasitic therapy.

Identification and Characterization of Entamoeba histolytica Choline Kinase

PURPOSE

Entamoeba histolytica is one of the death-causing parasites in the world. Study on its lipid composition revealed that it is predominated by phosphatidylcholine and phosphatidylethanolamine. Further study revealed that its phosphorylated metabolites might be produced by the Kennedy pathway. Here, we would like to report on the characterizations of enzymes from this pathway that would provide information for the design of novel inhibitors against these enzymes in future.

METHODOLOGY

E. histolytica HM-1:IMSS genomic DNA was isolated and two putative choline/ethanolamine kinase genes (EhCK1 and EhCK2) were cloned and expressed from Escherichia coli BL21 strain. Enzymatic characterizations were further carried out on the purified enzymes.

RESULTS

EhCK1 and EhCK2 were identified from E. histolytica genome. The deduced amino acid sequences were more identical to its homologues in human (35-48%) than other organisms. The proteins were clustered as ethanolamine kinase in the constructed phylogeny tree. Sequence analysis showed that they possessed all the conserved motifs in choline kinase family: ATP-binding loop, Brenner's phosphotransferase motif, and choline kinase motif. Here, the open reading frames were cloned, expressed, and purified to apparent homogeneity. EhCK1 showed activity with choline but not ethanolamine. The biochemical characterization showed that it had a Vmax of 1.9 ± 0.1 µmol/min/mg. Its Km for choline and ATP was 203 ± 26 µM and 3.1 ± 0.4 mM, respectively. In contrast, EhCK2 enzymatic activity was only detected when Mn2+ was used as the co-factor instead of Mg2+ like other choline/ethanolamine kinases. Highly sensitive and specific antibody against EhCK1 was developed and used to confirm the endogenous EhCK1 expression using immunoblotting.

CONCLUSIONS

With the understanding of EhC/EK importance in phospholipid metabolism and their unique characteristic, EhC/EK could be a potential target for future anti-amoebiasis study.

[Clinical and radiological differences between amoebic and pyogenic liver abscess: A case-control study]

INTRODUCTION

Amoebic liver abscess (ALA) is the fourth cause of mortality by parasitic infection. This study aimed to assess clinical, radiological and therapeutic characteristics of patients admitted for amoebic liver abscess compared to pyogenic abscess in a French digestive tertiary care-centre.

MATERIAL AND METHOD

The charts of patients hospitalized for a liver abscess between 2010 and 2020 were retrospectively assessed then separated in two groups: amoebic liver abscess and pyogenic liver abscess from portal underlying cause. Clinical and radiological data were collected for univariate comparison.

RESULTS

Twenty-one patients were hospitalized during the time of the study for ALA, and 21 patients for pyogenic liver abscess with a portal mechanism. All patients hospitalized for ALA lived in and/or had travelled recently in an endemic area. In comparison with patients hospitalized for pyogenic abscess, patients admitted for ALA were younger (44years old vs. 63years old, P<0.001), had less comorbidities (5% vs. 43% of patients with at least one comorbidity, P<0.01), a longer median duration of symptoms (10days vs. 3days, P=0.015), abdominal pain (86% vs. 52%, P=0.019), and a slighter leucocytosis (9600G/L vs. 15,500G/L, P=0.041) were more frequent. On the abdominal tomodensitometry, density of ALA was higher (34 vs. 25 UH, P<0.01), associated with a focal intra-hepatic biliary dilatation and less often multiloculated.

CONCLUSION

While rare in western countries, amoebic liver abscess care should not be underestimated. The presence of a solitary liver abscess of intermediate density on computed tomography, occurring on a patient returning from an endemic zone should lead the physician to a possible diagnosis of ALA.

The Amoebicidal Activity of Diferrocenyl Derivatives: A Significant Dependence on the Electronic Environment

Amoebiasis is the second leading cause of death worldwide associated with parasitic disease and is becoming a critical health problem in low-income countries, urging new treatment alternatives. One of the most promising strategies is enhancing the redox imbalance within these susceptible parasites related to their limited antioxidant defense system. Metal-based drugs represent a perfect option due to their extraordinary capacity to stabilize different oxidation states and adopt diverse geometries, allowing their interaction with several molecular targets. This work describes the amoebicidal activity of five 2-(Z-2,3-diferrocenylvinyl)-4X-4,5-dihydrooxazole derivatives (X = H (3a), Me (3b), iPr (3c), Ph (3d), and benzyl (3e)) on Entamoeba histolytica trophozoites and the physicochemical, experimental, and theoretical properties that can be used to describe the antiproliferative activity. The growth inhibition capacity of these organometallic compounds is strongly related to a fine balance between the compounds' redox potential and hydrophilic character. The antiproliferative activity of diferrocenyl derivatives studied herein could be described either with the redox potential, the energy of electronic transitions, logP, or the calculated HOMO-LUMO values. Compound 3d presents the highest antiproliferative activity of the series with an IC50 of 23 µM. However, the results of this work provide a pipeline to improve the amoebicidal activity of these compounds through the directed modification of their electronic environment.

Malaria and an Amoebic Abscess in a Returning Traveler from Liberia

Malaria is an infectious Anopheles mosquito-borne disease caused by five different eukaryotic protozoa parasites. Amoebiasis is a parasitic infection caused by Entamoeba histolytica. Both diseases are widespread in Liberia. A returning traveler was diagnosed and treated for malaria, and 20 days later, an amoebic liver abscess was discovered, meaning that the malaria infection masked the amoebic infection, which emphasizes the importance of a complete examination of returning travelers, especially for those returning from Sub-Saharan Africa, where coinfections are more common. Herein, we propose that the relationship between Malaria and amoebic liver abscesses should be explored by researching the effects of malaria on ferritin levels and the immune components in the liver and whether it helps the emergence of hepatic amoebic abscesses or not.

Intestinal Parasitic Infections in 2023

Intestinal parasites include intestinal protozoa and intestinal helminths. Intestinal parasitic infections (IPIs) pose a global health problem affecting over one billion people worldwide. Although these infections are predominantly seen in the developing world, they are frequently seen in the developed countries, particularly in immunocompromised patients. Patients' clinical presentations generally include diarrhea, dysentery, abdominal pain, nausea, vomiting, nutritional deficiency, iron deficiency anemia, anal and perianal itching, and rarely intestinal obstruction. The intestinal parasites have similarities in their mode of transmission and life cycle. The stool test is the primary way of diagnosing IPIs. Treatment is given with various anti-parasitic agents. However, appropriate preventive measures are essential for successfully controlling the IPIs.

Amebic liver abscess: Clinico-radiological findings and interventional management

In its classic form, amebic liver abscess (ALA) is a mild disease, which responds dramatically to antibiotics and rarely requires drainage. However, the two other forms of the disease, i.e., acute aggressive and chronic indolent usually require drainage. These forms of ALA are frequently reported in endemic areas. The acute aggressive disease is particularly associated with serious complications, such as ruptures, secondary infections, and biliary communications. Laboratory parameters are deranged, with signs of organ failure often present. This form of disease is also associated with a high mortality rate, and early drainage is often required to control the disease severity. In the chronic form, the disease is characterized by low-grade symptoms, mainly pain in the right upper quadrant. Ultrasound and computed tomography (CT) play an important role not only in the diagnosis but also in the assessment of disease severity and identification of the associated complications. Recently, it has been shown that CT imaging morphology can be classified into three patterns, which seem to correlate with the clinical subtypes. Each pattern depicts its own set of distinctive imaging features. In this review, we briefly outline the clinical and imaging features of the three distinct forms of ALA, and discuss the role of percutaneous drainage in the management of ALA.

Efficacy of laparoscopic surgery in the treatment of hepatic abscess: A systematic review and meta-analysis

Background

Liver abscess is a common cause of intra-abdominal infection and its treatment depends on the presentation. Laparoscopy, in addition to its classic benefits, has particular advantages in the management of liver abscess but its role is not well defined and studies done in that field are heterogenous. The objective of this systematic review is to evaluate the efficacy of laparoscopic surgery in the management of liver abscess.

Methods

We realized a systematic review and meta-analysis including studies published in the 20 last years. The primary outcome was the pooled prevalence of recurrent or residual liver abscess after laparoscopic treatment.

Results

We retrieved 190 studies regarding laparoscopic surgery in liver abscess and 17 studies were included in the quantitative and qualitative synthesis. A total of 608 patients was included and 299 of them (49.1%) were treated by laparoscopic surgery. The indications were mainly failure of first line treatment (antibiotic treatment and/or percutaneous drainage and/or needle aspiration) and ruptured multiloculated, or caudate lobe liver abscess. The surgical gesture performed was laparoscopic drainage in all studies. The post-operative rate of recurrent or residual liver abscess after treatment by laparoscopy was 4.22% (95% CI: 2.29–7.07).

Conclusions

This systematic review showed that laparoscopic drainage had a considerable place in the management. The post-operative rate of recurrence was low with no mortality suggesting that laparoscopy is safe and feasible for liver abscess management.

•

Surgery in the treatment for liver abscess has its indications limited to ruptured liver abscess, particularly in the peritoneal cavity.

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Laparoscopy can be used both for unruptured and ruptured liver abscess when there are failure or contraindications of percutaneous drainage.

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This review suggest the safety and feasibility of laparoscopy with a low rate of post-operative recurrent or residual liver abscess.

Drug Repurposing of the Alcohol Abuse Medication Disulfiram as an Anti-Parasitic Agent

Parasitic infections contribute significantly to worldwide morbidity and mortality. Antibiotic treatment is essential for managing patients infected with these parasites since control is otherwise challenging and there are no vaccines available for prevention. However, new antimicrobial therapies are urgently needed as significant problems exist with current treatments such as drug resistance, limited options, poor efficacy, as well as toxicity. This situation is made worse by the challenges of drug discovery and development which is costly especially for non-profitable infectious diseases, time-consuming, and risky with a high failure rate. Drug repurposing which involves finding new use for existing drugs may help to more rapidly identify therapeutic candidates while drastically cutting costs of drug research and development. In this perspective article, we discuss the importance of drug repurposing, review disulfiram pharmacology, and highlight emerging data that supports repurposing disulfiram as an anti-parasitic, exemplified by the major diarrhea-causing parasite Entamoeba histolytica.

Structure-Function Relationship Study of a Secretory Amoebic Phosphatase: A Computational-Experimental Approach

Phosphatases are hydrolytic enzymes that cleave the phosphoester bond of numerous substrates containing phosphorylated residues. The typical classification divides them into acid or alkaline depending on the pH at which they have optimal activity. The histidine phosphatase (HP) superfamily is a large group of functionally diverse enzymes characterized by having an active-site His residue that becomes phosphorylated during catalysis. HP enzymes are relevant biomolecules due to their current and potential application in medicine and biotechnology. Entamoeba histolytica, the causative agent of human amoebiasis, contains a gene (EHI_146950) that encodes a putative secretory acid phosphatase (EhHAPp49), exhibiting sequence similarity to histidine acid phosphatase (HAP)/phytase enzymes, i.e., branch-2 of HP superfamily. To assess whether it has the potential as a biocatalyst in removing phosphate groups from natural substrates, we studied the EhHAPp49 structural and functional features using a computational-experimental approach. Although the combined outcome of computational analyses confirmed its structural similarity with HP branch-2 proteins, the experimental results showed that the recombinant enzyme (rEhHAPp49) has negligible HAP/phytase activity. Nonetheless, results from supplementary activity evaluations revealed that rEhHAPp49 exhibits Mg²⁺-dependent alkaline pyrophosphatase activity. To our knowledge, this study represents the first computational-experimental characterization of EhHAPp49, which offers further insights into the structure-function relationship and the basis for future research.

COVID-19 and Corticosteroids: Unfamiliar but Potentially Fatal Infections That Can Arise following Short-Course Steroid Treatment

Corticosteroid use is increasing worldwide as recent studies confer survival benefit of corticosteroids in the management of patients with severe COVID-19. Strongyloides and amebic infections are neglected diseases that can progress to catastrophic complications in patients exposed to corticosteroids, even with short treatment courses. To prevent lethal outcomes, clinicians should be aware of the threat these two parasitic infections pose to at-risk patients receiving corticosteroids, especially in the era of COVID-19.

COP9 signalosome is an essential and druggable parasite target that regulates protein degradation

Understanding how the protozoan protein degradation pathway is regulated could uncover new parasite biology for drug discovery. We found the COP9 signalosome (CSN) conserved in multiple pathogens such as Leishmania, Trypanosoma, Toxoplasma, and used the severe diarrhea-causing Entamoeba histolytica to study its function in medically significant protozoa. We show that CSN is an essential upstream regulator of parasite protein degradation. Genetic disruption of E. histolytica CSN by two distinct approaches inhibited cell proliferation and viability. Both CSN5 knockdown and dominant negative mutation trapped cullin in a neddylated state, disrupting UPS activity and protein degradation. In addition, zinc ditiocarb (ZnDTC), a main metabolite of the inexpensive FDA-approved globally-available drug disulfiram, was active against parasites acting in a COP9-dependent manner. ZnDTC, given as disulfiram-zinc, had oral efficacy in clearing parasites in vivo. Our findings provide insights into the regulation of parasite protein degradation, and supports the significant therapeutic potential of COP9 inhibition.