Mycobacterium tuberculosis Beijing in the State of Nuevo Leon, Mexico.

Tuberculosis remains a serious threat to human health as an infectious disease in Mexico. Data about the genotypes of circulating Mycobacterium tuberculosis isolates (MTB) in the State of Nuevo Leon, Mexico are scarce. We aimed to determine the genotypes of circulating MTB belonging to the Beijing lineage recovered from patients in the State of Nuevo Leon, Mexico. A total of 406 MTB isolates from this state were genotyped using the spoligotyping method and 18-locus MIRU-VNTR. Lineage classification and MTB transmission analysis were performed. Based on the spoligotyping analysis, we found 24 strains belonging to the Beijing genotype that were characterized phylogenetically. The MIRUs showed greater discriminatory power than the standard RFLP-IS6110 method; therefore, the greatest allelic diversity among the Beijing strains was observed with MIRU10, MIRU31, MIRU39, MRU40, and MIRU 26. MVLA analysis showed a profile variation between Beijing and non-Beijing strains. The minimum spanning tree (MST) showed that 79% (19) of the strains are related. All Beijing strains exhibited the deletion of region TbD1, which is a characteristic of modern strains. The application of spoligotyping and MIRU-VNTR-18 methods together proved to be more sensitive, discriminatory, and rapid than the standard method for the epidemiological analysis of Mycobacterium Beijing isolates. This study is one of the first to describe the genomic diversity of M. Beijing in the State of Nuevo Leon, Mexico.

Identification of variants in genes associated with hypertrophic cardiomyopathy in Mexican patients.

The objective of this work was to identify genetic variants in Mexican patients diagnosed with hypertrophic cardiomyopathy (HCM). According to world literature, the genes mainly involved are MHY7 and MYBPC3, although variants have been found in more than 50 genes related to heart disease and sudden death, and to our knowledge there are no studies in the Mexican population. These variants are reported and classified in the ClinVar (PubMed) database and only some of them are recognized in the Online Mendelian Information in Men (OMIM). The present study included 37 patients, with 14 sporadic cases and 6 familial cases, with a total of 21 index cases. Next-generation sequencing was performed on a predesigned panel of 168 genes associated with heart disease and sudden death. The sequencing analysis revealed twelve (57%) pathogenic or probably pathogenic variants, 9 of them were familial cases, managing to identify pathogenic variants in relatives without symptoms of the disease. At the molecular level, nine of the 12 variants (75%) were single nucleotide changes, 2 (17%) deletions, and 1 (8%) splice site alteration. The genes involved were MYH7 (25%), MYBPC3 (25%) and ACADVL, KCNE1, TNNI3, TPM1, SLC22A5, TNNT2 (8%). In conclusion; we found five variants that were not previously reported in public databases. It is important to follow up on the reclassification of variants, especially those of uncertain significance in patients with symptoms of the condition. All patients included in the study and their relatives received family genetic counseling.

Vitamin supplementation increases the virulence of Entamoeba histolytica grown axenically.

As a consequence of axenic growth and the elimination of accompanying bacterial flora, Entamoeba histolytica virulence decreases rapidly, and pathogenicity is lost. This paper evaluated the impact of vitamin supplementation on the pathogenicity of E. histolytica. Growth of E. histolytica trophozoites, cultured axenically in PEHPS (a Spanish acronym for the main ingredients - casein peptone, liver, pancreas extract and bovine serum) medium, with or without vitamins, exhibited a similar growth rate. However, the vitamin-enriched PEHPS preparations expressed 2.65 times more haemolytic activity (at 60 min: 98 vs 48%, P < 0.05), 2.5 times more phospholipase A2 activity at 150 min of incubation and generated more hepatic abscesses (88 vs 60%, P = 0.05) than the preparations without vitamins. The haemolytic and phospholipase A2 activity for the PEHPS - V preparations were restored following vitamin supplementation with A and D. These data highlight, for the first time, that vitamins and specifically vitamin A and D were essential for the recovery of amoebic virulence, lost through axenic growth.

An acidic sphingomyelinase Type C activity from Mycobacterium tuberculosis.

Sphingomyelinases (SMases) catalyze the hydrolysis of sphingomyelin to ceramide and phosphorylcholine. Sphingolipids are recognized as diverse and dynamic regulators of a multitude of cellular processes mediating cell cycle control, differentiation, stress response, cell migration, adhesion, and apoptosis. Bacterial SMases are virulence factors for several species of pathogens. Whole cell extracts of Mycobacterium tuberculosis strains H37Rv and CDC1551 were assayed using [N-methyl-(14)C]-sphingomyelin as substrate. Acidic Zn(2+)-dependent SMase activity was identified in both strains. Peak SMase activity was observed at pH 5.5. Interestingly, overall SMase activity levels from CDC1551 extracts are approximately 1/3 of those of H37Rv. The presence of exogenous SMase produced by M. tuberculosis during infection may interfere with the normal host inflammatory response thus allowing the establishment of infection and disease development. This Type C activity is different from previously identified M. tuberculosis SMases. Defining the biochemical characteristics of M. tuberculosis SMases helps to elucidate the roles that these enzymes play during infection and disease.

Naphthoquinones isolated from Diospyros anisandra exhibit potent activity against pan-resistant first-line drugs Mycobacterium tuberculosis strains.

BACKGROUND AND OBJECTIVES: The recent emergence of multidrug-resistant (MDR), extensively drug-resistant (XDR), and totally drug-resistant (TDR) Mycobacterium tuberculosis (MTB) strains have further complicated the control of tuberculosis (TB). There is an urgent need of new molecules candidates to be developed as novel, active, and less toxic anti-tuberculosis (anti-TB) drugs. Medicinal plants have been an excellent source of leads for the development of drugs, particularly as anti-infective agents. In previous studies, the non-polar extract of Diospyros anisandra showed potent anti-TB activity, and three monomeric and five dimeric naphthoquinones have been obtained. In this study, we performed bioguided chemical fractionation and the isolation of eight naphthoquinones from D. anisandra and their evaluation of anti-TB and cytotoxic activities against mammalian cells. METHODS: The n-hexane crude extract from the stem bark of the plant was obtained by maceration and liquid-liquid fractionation. The isolation of naphthoquinones was carried out by chromatographic methods and identified by gas chromatography and mass spectroscopy data analysis. Anti-TB activity was evaluated against two strains of MTB (H37Rv) susceptible to all five first-line anti-TB drugs and a clinical isolate that is resistant to these medications (pan-resistant, CIBIN 99) by measuring the minimal inhibitory concentration (MIC). Cytotoxicity of naphthoquinones was estimated against two mammalian cells, Vero line and primary cultures of human peripheral blood mononuclear (PBMC) cells, and their selectivity index (SI) was determined. RESULTS: Plumbagin and its dimers maritinone and 3,3'-biplumbagin showed the strongest activity against both MTB strains (MIC = 1.56-3.33 µg/mL). The bioactivity of maritinone and 3,3'-biplumbagin were 32 times more potent than rifampicin against the pan-resistant strain, and both dimers showed to be non-toxic against PBMC and Vero cells. The SI of maritinone and 3,3'-biplumbagin on Vero cells was 74.34 and 194.11 against sensitive and pan-resistant MTB strains, respectively. CONCLUSION: Maritinone and 3,3'-biplumbagin possess a very interesting potential for development as new drugs against M. tuberculosis, mainly resistant profile strains.

[Primary cutaneous coccidioidomycosis in an infant]. / Coccidioidomicosis cutánea primaria en infante.

Coccidioidomycosis is a systemic granulomatosis caused by dimorphic fungi Coccidioides immitis, which are endemic of the San Joaquin Valley in California, USA, and C. posadasii found in the southwestern desert of the USA, Mexico, and South America. The primary cutaneous form is extremely infrequent. There have been 25 reported cases in literature, all of them in adults. This is the first case in an infant.

Evaluation of DNA damage in obese children using the chromatin dispersion test.

Childhood obesity predicts adult obesity and may increase the lifetime risk of adverse health outcomes. Obesity is characterized by oxidative stress that can induce DNA damage; however, studies of childhood and adolescent obesity are scarce. We investigated DNA damage due to obesity in Mexican children using the chromatin dispersion test (CDT). We evaluated DNA damage to peripheral lymphocytes of 32 children grouped according to body mass index as normal weight (controls), overweight and obese groups using guidelines from the Centers for Disease Control (CDC). We found that the greatest DNA damage occurred in cells of obese children compared to normal weight and overweight children. Our findings support preventive action to obviate adverse health outcomes due to obesity.

Prevalence of obesity, diabetes and hypertension in immigrant populations in northeastern Mexico.

Introduction: Hispanic immigrants are a fast-growing population in the United States of America (USA) that disproportionately suffer from chronic diseases. Despite the increasing prevalence of obesity in Latin-American countries, only a few studies have examined the onset of chronic diseases in Mexican and Central American migrants in Mexico. Objective: The objective of this study is to determine the prevalence of obesity, diabetes, and hypertension in Central American immigrants who are in the process of traveling through northeastern Mexico to the United States. Methods: An observational, descriptive, cross-sectional study was conducted among migrants, mostly Central Americans. Migrants who agreed to participate in the study were interviewed face-to-face by researchers to obtain their sociodemographic data. To obtain the prevalence, many health indicators related to obesity, diabetes, and hypertension, including weight, height, fasting glucose, and blood pressure, were measured. Results: In total, 520 migrants were interviewed; sociodemographic data indicated that most participants were men (76%), from Honduras (72.6%), single (61.2%), and have elementary level of education (48.6%). The somatometric evaluation revealed that 28.9% were diagnosed as overweight, 10.7% with obesity, and 3.3% with malnutrition. Of less prevalence, 8.8% were detected with hypertension and 4.6% had fasting hyperglycemia. The mean participant age was 29.11 ± 10.00 years. For each participant, the average weight was 66.72 ± 13.09 kg; the average height was 1.64 ± 0.08 m; the average body mass index (BMI) was 24.59 ± 4.32; the mean systolic and diastolic pressures were 116.26 ± 15.13 and 74 ± 9.65, respectively; and the average glycemia was 100.97 ± 21.99. El Salvador showed the highest proportion of people with diabetes (14.7%). Women who participated in this study had a higher proportion of obesity (23.4%, p = 0.02) and overweight (36.2%) than men (8.4 and 29.2%, respectively). People from Mexico, Nicaragua, and Honduras reported a high prevalence of overweight participants (63.6, 47.4, and 30.7%, respectively), while people from El Salvador and Nicaragua had a high prevalence of obese participants (23.5 and 21.1%, respectively). Conclusion: We found significant differences in the rates of obesity, diabetes, and hypertension between groups of Central American migrants and their place of origin, age, educational level, and gender. Our findings highlight the importance of exploring differences within groups of Central American migrants traveling through northeastern Mexico to the United States, which may explain several health indicators.

Update on Pediatric Sepsis in Mexico.

The main objective of this work was to determine and update the causal agents' antibiotic sensitivity and resistance patterns on pediatric sepsis in a population of northeast Mexico. It is a cross-sectional study showing the results of blood cultures of pediatric patients with a presumptive diagnosis of sepsis were reviewed according to the SOFA criteria during 2020 in a public hospital in Mexico. A total of 207 blood cultures were performed and analyzed. The main isolated microorganisms were Staphylococcus, followed by Klebsiella and Escherichia. Several microorganisms showed 100% of sensitivity to different antibiotics or antifungals, some of them include Vancomycin, Voriconazole, Meropenem, Ciprofloxacin, and Cefotaxime. Bacteria of genre Staphylococcus showed its highest sensitivity rate to Tigecycline with 63.3%. Too Staphylococcus showed the highest resistance rate to Oxacillin with 50%. Although the patterns of sepsis-causing germs are similar to those previously reported, the development of new drugs with greater efficacy is the main contribution.

Applying systems thinking to identify enablers and challenges to scale-up interventions for hypertension and diabetes in low-income and middle-income countries: protocol for a longitudinal mixed-methods study.

INTRODUCTION: There is an urgent need to reduce the burden of non-communicable diseases (NCDs), particularly in low-and middle-income countries, where the greatest burden lies. Yet, there is little research concerning the specific issues involved in scaling up NCD interventions targeting low-resource settings. We propose to examine this gap in up to 27 collaborative projects, which were funded by the Global Alliance for Chronic Diseases (GACD) 2019 Scale Up Call, reflecting a total funding investment of approximately US$50 million. These projects represent diverse countries, contexts and adopt varied approaches and study designs to scale-up complex, evidence-based interventions to improve hypertension and diabetes outcomes. A systematic inquiry of these projects will provide necessary scientific insights into the enablers and challenges in the scale up of complex NCD interventions. METHODS AND ANALYSIS: We will apply systems thinking (a holistic approach to analyse the inter-relationship between constituent parts of scaleup interventions and the context in which the interventions are implemented) and adopt a longitudinal mixed-methods study design to explore the planning and early implementation phases of scale up projects. Data will be gathered at three time periods, namely, at planning (TP), initiation of implementation (T0) and 1-year postinitiation (T1). We will extract project-related data from secondary documents at TP and conduct multistakeholder qualitative interviews to gather data at T0 and T1. We will undertake descriptive statistical analysis of TP data and analyse T0 and T1 data using inductive thematic coding. The data extraction tool and interview guides were developed based on a literature review of scale-up frameworks. ETHICS AND DISSEMINATION: The current protocol was approved by the Monash University Human Research Ethics Committee (HREC number 23482). Informed consent will be obtained from all participants. The study findings will be disseminated through peer-reviewed publications and more broadly through the GACD network.

Latent tuberculosis infection in medical students in the Northeast of Mexico.

BACKGROUND: Medical students are considered to be personnel with a high level of risk for developing latent tuberculosis infection (LTBI). One possible reason is lack of knowledge about the transmission, prevention, and biosafety standards for tuberculosis disease. OBJECTIVE: This research aimed to determine the rate of LTBI among medical students studying in a private School of Medicine in Monterrey, Mexico. METHODS: In this cross-sectional study, we obtained blood samples from 174 medical students. LTBI was diagnosed using the QuantiFERON®-TB Gold Plus test. The prevalence of LTBI was compared with the socio-demographic data of the students and their level of knowledge and use of personal protective equipment (PPE). RESULTS: The proportion of LTBI in the students was 20.6%. Medical students in their first few years of medical school had a lower prevalence of LTBI than students in their final years of medical school. Additionally, students with a low level of knowledge on LTBI and low use of proper PPE had a higher prevalence of LTBI. CONCLUSIONS: In a School of Medicine in Monterrey, Mexico, the proportion of medical students with LTBI was low but the proportion increased in advanced students. Students who demonstrated adequate knowledge and use of respiratory protective masks had lower prevalence rates for LTBI.

Risk Factors for SARS-CoV-2 Infection, Pneumonia, Intubation, and Death in Northeast Mexico.

Despite the social distancing and mobility restriction measures implemented for susceptible people around the world, infections and deaths due to COVID-19 continued to increase, even more so in the first months of 2021 in Mexico. Thus, it is necessary to find risk groups that can benefit from more aggressive preventive measures in a high-density population. This is a case-control study of suspected COVID-19 patients from Nuevo León, Mexico. Cases were: (1) COVID-19-positive patients and COVID-19-positive patients who (2) developed pneumonia, (3) were intubated and (4) died. Controls were: (1) COVID-19-negative patients, (2) COVID-19-positive patients without pneumonia, (3) non-intubated COVID-19-positive patients and (4) surviving COVID-19-positive patients. ≥ 18 years of age, not pregnant, were included. The pre-existing conditions analysed as risk factors were age (years), sex (male), diabetes mellitus, hypertension, chronic obstructive pulmonary disease, asthma, immunosuppression, obesity, cardiovascular disease, chronic kidney disease and smoking. The Mann-Whitney U tests, Chi square and binary logistic regression were used. A total of 56,715 suspected patients were analysed in Nuevo León, México, with 62.6% being positive for COVID-19 and, of those infected, 14% developed pneumonia, 2.9% were intubated and 8.1% died. The mean age of those infected was 44.7 years, while of those complicated it was around 60 years. Older age, male sex, diabetes, hypertension, and obesity were risk factors for infection, complications, and death from COVID-19. This study highlights the importance of timely recognition of the population exposed to pre-existing conditions to prioritise preventive measures against the virus.

Epidemiologic Impacts in Acute Infectious Disease Associated with Catastrophic Climate Events Related to Global Warming in the Northeast of Mexico.

Rising global temperatures and seawater temperatures have led to an increase in extreme weather patterns leading to droughts and floods. These natural phenomena, in turn, affect the supply of drinking water in some communities, which causes an increase in the prevalence of diseases related to the supply of drinking water. The objective of this work is to demonstrate the effects of global warming on human health in the population of Monterrey, Mexico after Hurricane Alex. We interpolated data using statistical downscaling of climate projection data for 2050 and 2080 and correlated it with disease occurrence. We found a remarkable rise in the incidence of transmissible infectious disease symptoms. Gastrointestinal symptoms predominated and were associated with drinking of contaminated water like tap water or water from communal mobile water tanks, probably because of the contamination of clean water, the disruption of water sanitation, and the inability to maintain home hygiene practices.

Acellular fraction from malignant effusions has cytotoxicity in breast cancer cells.

Malignant ascites (MA) and malignant pleural effusion (MPE) are frequently developed in patients with metastatic cancer; however, the biological properties of these fluids have not been clarified. The present study explored the biological role of a low molecular fraction derived from malignant effusions on the activation of peripheral blood mononuclear cells and on the proliferation of breast cancer cells and fibroblast 55x cells. A <10-kDa fraction from effusions of 41 oncological patients and 34 individuals without cancer was purified, and its potential role in inhibiting nitric oxide (NO) production on lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells was explored, as well as its cytotoxicity on MCF-7 breast cancer cells and fibroblast 55x cells. A significant decrease in NO production was observed in the <10-kDa fraction from malignant effusions. In addition, the acellular fraction from MA decreased the viability of breast cancer cells without affecting human fibroblasts. These data support the presence of low molecular weight molecules in malignant samples with a specific role in inhibiting the defense mechanisms of peripheral blood mononuclear cells and decreasing the viability of breast cancer cells in vitro.

Entamoeba histolytica: soluble and membrane-associated neutral sphingomyelinase-C and other unidentified esterase activity.

Sphingomyelinase (SMase) activity was measured in Entamoeba histolytica particulate and soluble subcellular fractions. The effects on SMase of incubation time, total protein concentration, pH, and several divalent cations were determined. SMase-C and other unidentified esterase activity were detected in soluble and particulate fractions. SMase-C was 94.5-96.0% higher than the unidentified esterase activity. Soluble and insoluble SMase-C specific activities increased with protein dose and incubation time. Soluble and insoluble SMase-C activities were maximum at pH 7.5 and were dependent on Mg(2+), Mn(2+), or Co(2+), and inhibited by Zn(2+), Hg(2+), Ca(2+), and EDTA. SMase-C was active in the pH range of 3-10 and its maximum activity was at pH 7.5. The soluble and insoluble SMases have remarkably similar physicochemical properties, strongly suggesting that E. histolytica has just one isoform of neutral SMase-C that had not been described before and might be essential for E. histolytica metabolism or virulence.

Congenital epulis of the newborn, criteria for the approach. Case report / Épulis congénito del recién nacido, criterios para el abordaje. Reporte de caso

BACKGROUND: The newborn congenital epulis or granular cell tumor is a benign tumor that appears in the oral cavity of newborns with more frequency in the gingiva of the alveolar crest of the maxilla at the level of the incisive and canine area, predominantly in the female sex. It is of diagnostic importance since it can interfere with feeding, swallowing and via area, putting the health of the newborn at risk. It usually involutes spontaneously and in case of surgical treatment there are no reports of recurrence. The aim of this work was to describe the evolution according to the approach of this patient with congenital newborn epulis. CASE REPORT: The case of a patient of the newborn congenital epulis and its follow-up for 6 years is reviewed. CONCLUSIONS: The surgical treatment of the newborn congenital epulis seems to be a good option of approach without the difficulties in the feeding, suction and breathing of the newborn.

INTRODUCCIÓN: El épulis congénito del recién nacido, o tumor de células granulares, es un tumor benigno que aparece en cavidad oral de los recién nacidos, con mayor frecuencia en la encía de la cresta alveolar del maxilar a nivel del área incisiva y canina, predominando en el sexo femenino. Es de importancia diagnóstica, ya que puede interferir con la alimentación, la deglución y la vía área, poniendo en riesgo la salud del recién nacido. Generalmente involuciona de manera espontánea y, en caso de tratamiento quirúrgico, no hay informes de recurrencia. Decidir la forma de abordaje en un recién nacido, por la complejidad y la inmadurez del organismo, implica un gran reto para los neonatólogos, los cirujanos pediatras y los especialistas del área bucal, como son los odontopediatras y los cirujanos maxilofaciales. El objetivo de este trabajo fue describir la evolución según el abordaje de esta paciente con épulis congénito del recién nacido. CASO CLÍNICO: Se revisa el caso de una paciente con épulis congénito del recién nacido tratada quirúrgicamente y su seguimiento durante 6 años. CONCLUSIONES: De acuerdo con la evolución de este caso se puede concluir que el tratamiento quirúrgico puede ser una buena opción de abordaje sin que se presenten dificultades en la alimentación, la succión ni la respiración.

Latent tuberculosis in migrants travelling through the northeast regions of Mexico.

BACKGROUND: Latent tuberculosis infection (LTBI) affects nearly a quarter of the global population. Public health interventions aimed at interrupting tuberculosis transmission do not routinely include systematic screening of migrant populations for LTBI in Mexico, nor other high-income countries. However, early detection and treatment of LTBI in immigrant populations from high-burden countries are recommended by the World Health Organization. OBJECTIVE: The objective of this study was to determine the proportion of migrants with LTBI in shelters in northeastern Mexico. METHODS: In this cross-sectional study, blood samples were obtained from 455 migrants living in shelters in northeastern Mexico during January 2017 to October 2019. LTBI was diagnosed using the QuantiFERON®-TB Gold Plus test. RESULTS: Most of the migrants evaluated in this study were from Honduras; ∼86% were male; the average age was 29 ±â€¯10 years. LTBI was identified in 18.4% of those from Central America. Migrants from El Salvador and Nicaragua were more likely to have LTBI than those from Honduras or Guatemala. Overweight or obese persons and older persons had a higher prevalence of LTBI. We detected no significant differences with respect to LTBI when the results were compared based on gender, education, or marital status. CONCLUSION: The LTBI rates amongst migrants from Central America recently screened in shelters in northeastern Mexico appears to be relatively low given recent estimates of LTBI prevalence in Mexico.

Venoarterial extracorporeal membrane oxygenation in heart surgery post-operative pediatric patients: A retrospective study at Christus Muguerza Hospital, Monterrey, Mexico.

OBJECTIVES: Extracorporeal membrane oxygenation is a life support procedure developed to offer cardiorespiratory support when conventional therapies have failed. The purpose of this study is to describe the findings during the first years using venoarterial extracorporeal membrane oxygenation in pediatric patients after cardiovascular surgery at Christus Muguerza High Specialty Hospital in Monterrey, Mexico. METHODS: This is a retrospective, observational, and descriptive study. The files of congenital heart surgery post-operative pediatric patients, who were treated with venoarterial extracorporeal membrane oxygenation from January 2013 to December 2015, were reviewed. RESULTS: A total of 11 patients were reviewed, of which 7 (63.8%) were neonates and 4 (36.7%) were in pediatric age. The most common diagnoses were transposition of great vessels, pulmonary stenosis, and tetralogy of Fallot. Survival rate was 54.5% and average life span was 6.3 days; the main complications were sepsis (36.3%), acute renal failure (36.3%), and severe cerebral hemorrhage (9.1%). The main causes of death were multi-organ dysfunction syndrome (27.3%) and cerebral hemorrhage (18.2%). CONCLUSION: The mortality rates found are very similar to those found in a meta-analysis report published in 2013 and the main complication and causes of death are also very similar to the majority of extracorporeal membrane oxygenation reports for these kinds of patients. Although the results are encouraging, early sepsis detection, prevention of cerebral hemorrhage, and renal function monitoring must be improved.

[Sensibility of Entamoeba histolytica trophozoites to ivermectin]. / Sensibilidad de trofozoítos de Entamoeba histolytica a ivermectina.

Amebiasis caused by Entamoeba histolytica is a problem of public world health. The most frequent clinical presentation are the dysentery and the amebic liver abscess. Fifty millions of cases and more than 100.000 deaths for this disease are reported annually worldwide. The life cycle of E. histolytica has two phases: trophozoite and cyst. Trophozoites are the causal agent of disease. The effective treatment for the amebiasis includes drugs with serious collateral effects. Ivermectin is a macrolid with activity against endoparasites and ectoparasites causing strongiloidosis, filariasis, oncocercosis, scabiasis and pediculosis. The use of ivermectin has been extended almost worldwide; it is recognized as a safe drug. The main objective of this study was to determine in vitro sensibility of trophozoites of E. histolytica was to the treatment with ivermectin. To determine the sensibility of the parasites to the drug, E. histolytica was cultivated in PEHPS medium. During its logarithmic growth phase the trophozoites were exposed to different concentrations of ivermectin. As controls other antiparasitic drugs were used. For each drug, serial dilutions were prepared, and mixed in culture tubes with parasites (2 x 104 cells/ml). They were incubated for 72 h and then the percentage of growth inhibition was calculated by Probit analysis. Ivermectin showed activity against trophozoites of E. histolytica. The 50% of growth inhibition of ivermectin was 6.40 mg/ml. This dose was higher than for other anti parasitic drugs. Its activity in vivo in animal models remains to be demonstrated.