A Comparative Analysis of Microscopy, Coproantigen Serology, and Nested Multiplex PCR in the Laboratory Diagnosis of Entamoeba histolytica Infection

Objectives Amoebiasis is caused by the most common intestinal protozoan parasite Entamoeba histolytica. This parasite causes amoebic colitis, which is manifested by diarrhea, followed by dysentery. The laboratory diagnosis of intestinal amoebiasis in most cases is by microscopic examination of stool samples. Other nonroutine methods include coproantigen enzyme-linked immunosorbent assay (ELISA) from stool samples, serum ELISA for antibodies, stool culture, isoenzyme analysis, and polymerase chain reaction (PCR). The present study aimed to comparatively analyze the different diagnostic modalities used for the detection of E. histolytica from the stool sample of patients with intestinal amoebiasis. Materials and Methods This study was undertaken with 631 patients, during a period of 3 years, from January 2017 to December 2019. Stool specimen obtained from each patient was subjected to direct microscopic wet mount examination, coproantigen ELISA, and nested multiplex PCR, respectively. Results Out of all the patients tested, 5.2% were positive for E. histolytica. Among the positive cases, stool microscopy was positive in 3.17%, coproantigen ELISA was positive in 29 (4.6%) cases, and PCR was positive in 30 (4.75%) cases. Statistical Analysis The prevalence of E. histolytica infection was summarized as percentages. The three diagnostic tests done were statistically analyzed, taking microscopy as the gold standard. The agreement between techniques (microscopy, coproantigen ELISA, and PCR) was analyzed with kappa statistics. Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were summarized as percentage with 95% confidence interval. Conclusion In all suspected amoebiasis cases, a combination of stool microscopy, coproantigen testing with molecular detection of the parasite offers the best approach to diagnosis of this parasitic infection.

Case report: multiple and atypical amoebic cerebral abscesses resistant to treatment

Background The parasite Entamoeba histolytica is the causal agent of amoebiasis, a worldwide emerging disease. Amebic brain abscess is a form of invasive amebiasis that is both rare and frequently lethal. This condition always begins with the infection of the colon by E. histolytica trophozoites, which subsequently travel through the bloodstream to extraintestinal tissues. Case presentation We report a case of a 71-year-old female who reported an altered state of consciousness, disorientation, sleepiness and memory loss. She had no history of hepatic or intestinal amoebiasis. A preliminary diagnosis of colloidal vesicular phase neurocysticercosis was made based on nuclear magnetic resonance imaging (NMRI). A postsurgery immunofluorescence study was positive for the 140 kDa fibronectin receptor of E. histolytica, although a serum analysis by ELISA was negative for IgG antibodies against this parasite. A specific E. histolytica 128 bp rRNA gene was identified by PCR in biopsy tissue. The final diagnosis was cerebral amoebiasis. The patient underwent neurosurgery to eliminate amoebic abscesses and was then given a regimen of metronidazole, ceftriaxone and dexamethasone for 4 weeks after the neurosurgery. However, a rapid decline in her condition led to death. Conclusions The present case of an individual with a rare form of cerebral amoebiasis highlights the importance of performing immunofluorescence, NMRI and PCR if a patient has brain abscess and a poorly defined diagnosis. Moreover, the administration of corticosteroids to such patients can often lead to a rapid decline in their condition.

Tiberal (Ro 7-0207-Roche) in the Treatment of Intestinal Amoebiasis - Part II

Twenty-four intestinal amoebiasis patients have been treated with a new amoebicid tiberal (Roche) or metronidazole as a control in a dosage of 15- 30 mg/kg body weight per day for 5 consecutive days. The results show that both drugs achieve a 100% cure rate. No side effects or signs of drug toxicity as evaluated from the results of the safety tests were observed. No signs of clinical or parasitological relapses were seen (after discharge. In comparison with the previous trial with a lower dosage (7~ - 15 mg.) and longer course (7 days) the results were even better, e.g. clinical improvement and parasitological disappearance were achieved in a shorter time.

An underestimated sexually transmitted infection: amoebiasis

Entamoeba histolytica is a cosmopolitan pathogenic parasite. It is spread via the feco-oral route and, to a lesser extent, via sexual intercourse. We report a case of hepatic and intestinal amoebiasis in a 67-year-old man who had never travelled to an endemic area. Abdominal CT investigations detected two liver abscesses and chronic colitis. Positive amoebic serology and a positive PCR test for E. histolytica in the hepatic liquid and faeces confirmed the diagnosis. Curative metronidazole and tiliquinol-tilbroquinol were administered successfully. The patient had been contaminated through heterosexual intercourse with his healthy French female partner who was a carrier of the parasite. Though unusual, amoebiasis as a result of sexual transmission should be considered in non-endemic areas in people who have never travelled abroad, particularly in the presence of clinical symptoms such as liver abscesses or chronic diarrhoea.

Synthetic bovine lactoferrin peptide Lfampin kills Entamoeba histolytica trophozoites by necrosis and resolves amoebic intracecal infection in mice

Amoebiasis caused by the protozoan parasite Entamoeba histolytica remains a public health problem in developing countries, making the identification of new anti-amoebic compounds a continuing priority. Previously, we have shown that lactoferrin (Lf) and several Lf-derived peptides exhibit in vitro anti-amoebic activity independently of their iron-binding activity. Here, we evaluated the amoebicidal effect of synthetic Lf-derived peptides Lfcin-B, Lfcin 17-30, and Lfampin, analyzed the mechanism of death induced by the peptides and determined their therapeutic effects on murine intestinal amoebiasis. MTT assays in trophozoite cultures of E. histolytica exposed to each peptide (1–1000 μM) showed that Lfampin is far more amoebicidal than Lfcins. Lfampin killed 80% of trophozoites at doses higher than 100 μM in 24 h, and FACs analysis using Annexin V/propidium iodide showed that death occurred mainly by necrosis. In contrast, Lfcin-B and Lfcin 17-30 appeared to have no significant effect on amoebic viability. FACs and confocal microscopy analysis using FITC-labeled peptides showed that all three peptides are internalized by the amoeba mainly using receptor (PI3K signaling) and actin-dependent pathways but independent of clathrin. Docking studies identified cholesterol in the amoeba’s plasma membrane as a possible target of Lfampin. Oral treatment of intracecally infected mice with the abovementioned peptides at 10 mg/kg for 4 days showed that Lfampin resolved 100% of the cases of intestinal amoebiasis, whereas Lfcin 17-30 and Lfcin-B were effective in resolving infection in 80 and 70% of cases, respectively. These data show that although synthetic bovine Lf-derived peptides exhibit varying amoebicidal potentials in vitro, they do resolve murine intestinal amoebiasis efficiently, suggesting that they may be useful as a therapeutic treatment.

AGE FEATURES OF INTESTINAL AMOEBIASIS

Study objective. To establish clinical and epidemiological features of intestinal amebiasis in adults and children at the present stage. A retrospective analysis of patient histories of 90 cases of intestinal amebiasisin patients aged 3 to 40 years who were on inpatient treatment in Regional Infectious Clinical Hospital named after A.M Nichogi, Astrakhan, in the period from 2014 to 2017. The diagnosis of amebiasis was confirmed by microscopy of feces, detection of antibodies by using reaction of indirect hemagglutination (RHAG) with a specific antigen, determination of DNA of the parasite by polymerase chain reaction (PCR).Results. It was determined that the incidence of intestinal amebiasis in the Astrakhan region is sporadic with the involvement in the epidemic process of persons of working age from 18 to 40 years (75.6%) and children aged 3 to 10 years (24.6%) of organized groups living in the city. Acute intestinal amebiasis in 86.8% of adults proceeded in mild to moderate form. The clinical course of the disease was characterized by a gradual onset in 82.4%, mucosal-bloody stool in 94.1%, the outcome of a chronic recurrent form in 11.8%. Raspberry jelly-like stool, extraintestinal complications of amebiasis, characteristic of amebiasis of previous years, were absent.The features of intestinal amebiasis in children were: acute onset of the disease in 63.6%, fever 38°C and above in 54.5%, abdominal pain in 95.5%, prolonged diarrhoea with a stool frequency of more than 10 times in 72.7%, stool with blood mucus in 95.5%, tenesmus in 36.4%, dehydration in 18.6% of patients. The mild form of the disease in children was not observed, severe was observed in 54.5%, moderate in 45.5%. The combined course of intestinal amebiasis with bacterial dysentery, proceeded more severely, changed clinical symptoms of the disease, made it difficult to diagnose amebiasis in a timely manner.

Decreasing trend of seroprevalence of hepatic amoebiasis in tertiary care hospital of North India: 2010–2015

BACKGROUND: Globally, amoebic liver abscess, a common extraintestinal complication of intestinal amoebiasis. Diagnosis of hepatic amoebiasis is based on the detection of anti-Entamoeba histolytica immunoglobulin G (IgG) antibody using enzyme-linked immunosorbent assay (ELISA), because of its technique's relatively higher sensitivity and specificity (90%). AIM: The aim of the present study was to determine the seroprevalence of hepatic amoebiasis in a referral tertiary care hospital in North India. MATERIALS AND METHODS: The blood samples were tested specifically for anti-E. histolytica IgG antibody using commercially available ELISA kit (RIDASCREEN® E. histolytica IgG [K1721] kit). RESULTS: A total of 879 patients (n = 879) were evaluated, of which 78.49% (690/879) were positive for anti-E. histolytica IgG antibody. The seroprevalence rates showed a declining trend from 2010 to 2015 with rates falling from 91.4% to 66.7%. He present a study showed the decreasing trend of seroprevalence of hepatic amoebiasis from 2010 to 2015. CONCLUSIONS: This decrease may be attributed to several factors such as increase in awareness, improved hygienic practices, use of safe drinking water, better socioeconomic condition, and perhaps early treatment sought for intestinal amoebiasis.