Morphometric study of the small bowel mucosa in infants with diarrhea due to enteropathogenic Escherichia coli strains.

BACKGROUND/AIMS: Enteropathogenic Escherichia coli (EPEC) strains are the most important cause of gastroenteritis in infants under 1 year of age and may induce several patterns of villous atrophy in the intestinal mucosa. However, the interpretation of these abnormalities has usually been based on semiquantitative criteria, giving rise to considerably subjective results. We utilized the linear morphometry to analyze the morphological lesions of the small bowel mucosa induced by EPEC strains in infants with persistent diarrhea in comparison with those seen in infants with asymptomatic environmental enteropathy (AEE) and controls. METHODOLOGY: Fifty nine specimens of small bowel mucosa were comparatively studied and divided in the following groups: 1. Group I: Thirty infants with persistent diarrhea due to EPEC strains, mean age 6.4 months; 2. Group II: Sixteen infants with AEE, mean age 6.5 months with no enteropathogenic bacteria in stools; 3. Group III: Thirteen children with short stature and no gastrointestinal complaints, mean age 15 months. Morphometric analysis of the small bowel mucosa was performed by using a x10 objective to a Zeiss light microscope, to which a measuring Zeiss ocular, t8x was adapted. The following measurements were carried out: Total mucosal thickness (TMT); Villous height (VH); Crypt length (CL); Intraepithelial lymphocyte (IEL) count. RESULTS: Except for the IEL, there was a significant difference in all the parameters analyzed among the evaluated groups. Group I revealed the lowest values for total mucosal thickness, villous height, and the ratio villous height/crypt length in comparison with the two other groups. On the other hand, the crypt length measurements for Group II were larger than those for Groups I and III. The measurements of villous height and the ratio villous height/crypt length for Group III turned out to be greater than those for Group II. CONCLUSIONS: The utilization of an accurate technique in the morphological study of the small bowel mucosa allowed us to detect severe abnormalities not only in infants with EPEC infection, but also in those counterparts who live in contaminated environments, and can therefore potentially acquire this type of intestinal infection.

[Classic enteropathogenic Escherichia coli]. / Escherichia coli enteropatogênica clássica (EPEC).

Enteropathogenic Escherichia coli. (EPEC) are gram negative bacteria of great importance in the etiology of diarrhea in children under two years of age living in developing countries. It was first reported in 1946. Its pathogenic mechanism was unknown until 1970 when several papers were published in the attempt to find out their physiophatologic mechanism. These bacteria interfere on the small bowel resulting in parcial or sub total villous atrophy. This injury will revert when the infection subsides.

Morfometria do intestino delgado em crianças com diarréia por Escherichia coli enteropatogênica clássica e enteropatia ambiental assintomática / Morphometrics of the small bowel in children with diarrhea due to classical enteropathogenic Escherichia coli and to environmental asymptomatic enteropathy

Infecçäo entérica por Escherichia coli enteropatogênica clássica (EPEC) pode causar diferentes graus de alteraçöes das vilosidades do intestino delgado.OBJETIVOS. Este estudo teve por objetivo: 1) avaliar as alteraçöes morfológicas da mucosa intestinal na diarréia aguda por EPEC, por meio da morfometria linear, e compará-la a um grupo controle; 2) comparar o número de LIE encontrado na diarréia aguda e/ou persistente por EPEC com aqueles encontrados no grupo controle; 3) pesquisar a presença de E. coli aderida à mucosa do intestinodelgado naquelas crianças que apresentaram diarréia com coprocultura positiva para EPEC. PACIENTES E MÉTODOS. Foram analisados 30 biópsias da mucosa do intestino delgado de crianças com diarréia aguda e/ou persistente, com coprocultura positiva para EPEC e 16 biópsias obtidas da mucosa do intestino delgado de crianças portadoras de enteropatia ambiental assintomática, que constituíram nosso grupo controle. Foram realizadas as seguintes análises morfométricas: RESULTADOS: Espessura total mucosa µ EPEC=279,6 EAA=445,1 p<0,001; Altura vilosidade µ EPEC 134,3 EAA 248,0 p<0,001; Extensäo da zona críptica µ EPEC 145,2 EAA 197,1 p<0,02; linfócitos intra-epiteliais EPEC 11,6 EAA 15,5 p<0,005. CONCLUSÄO. Presença de bactéria gram-negativa, portanto, provavelmente, EPEC, foi constatada em três dos 30 pacientes com diarréia, apresentando coprocultura positiva para EPEC. As alteraçöes morfométricas ocorrem, principalmente, às custas da diminuiçäo das visolidades intestinais.

[Morphometrics of the small intestine in children with diarrhea due to classical enteropathogenic Escherichia coli and to environmental asymptomatic enteropathy]. / Morfometria do intestino delgado em crianças com diarréia por Escherichia coli enteropatogênica clássica e enteropatia ambiental assintomática.

The enteric EPEC infection may cause different degrees of abnormalities in the small bowel villi. Morphological changes in the small intestine have been described in asymptomatic children who live in unfavourable environmental conditions. Enteric EPEC infections frequently occur in children living in such conditions and may worsen the already existing lesions. OBJECTIVES--1) To evaluate the morphological changes of the morphometry and compare them to the intestinal mucosa of children bearing Asymptomatic Environmental Enteropathy (AEE). 2) To compare the number of intra-epithelial lymphocytes (IEL) found in acute and/or persistent diarrhea by EPEC to those ones found in the other two groups. MATERIAL AND METHODS--Thirty (30) specimens of small intestinal mucosa obtained from children having acute and/or persistent diarrhea by EPEC were analysed and then compared to the specimens of the small intestinal biopsy of sixteen (16) patients bearing AEE. The following measurements were performed: RESULTS-- [table: see text] CONCLUSIONS--The villous changes were more remarkable in EPEC infection but the crypt hypertrophy was significantly higher in patients with AEE. This fact is probably due to repeated damages caused by the environmental problems. The use of linear morphometry has been a relevant technique which allows to evaluate the possible small intestinal morphological changes more accurately than the subjective criteria. In this way, the application of this technique enables the comparative approach of determined values under statistical bases.

[Small bowel morphometry in acute and persistent diarrhea due to classic enteropathogenic Escherichia coli]. / Morfometria do intestino delgado na diarréia aguda ou persistente por Escherichia coli enteropatogênica clássica.

Enteropathogenic E.coli infection may cause different ranges of abnormalities in the small bowel villi, but there are no morphometric studies about it. Thirty specimens of small intestinal mucosa obtained from children having acute or persistent diarrhea by enteropathogenic E.coli were analysed and then compared to the specimens of the small intestinal biopsy of thirteen patients of the control group. We had the following target in this paper: evaluate the morphological changes of intestinal mucosa using linear morphometry and to verify the number of intra-epithelial lymphocytes/100 enterocytes; search the presence of Gram negative bacteria adhered to the small intestinal mucosa. Gram negative bacteria were present in three patients with acute diarrhea. The morphometric changes were more remarkable in the villosites which were shorter, in the enteropathogenic E.coli group. The total mucosa thickness as well as the villous height and the relation villous/crypt were significantly shorter in the enteropathogenic E.coli group when compared to the control Group. There were no differences between the two groups for the crypt length and for de number of intraepithelial lymphocytes/100 enterocytes.

[Cidade Leonor slum, São Paulo. II. Longitudinal clinical and anthropometric follow-up of infants during their first year of life]. / Observações sobre a favela da Cidade Leonor, São Paulo. II--Acompanhamento longitudinal clínico e antropométrico de crianças durante o primeiro ano de vida.

In this study, the authors performed a clinical and nutritional follow-up involving infants that live in a slum area of the City of São Paulo. The infants were followed since birth and up to the end of their first year of life. The nutritional status was evaluated considering the following criteria: weight/age, height/age, and weight/height indices. On the first visit, 38.6% of the infants already presented protein-calory malnutrition according to the weight/age index, and 31.1% presented early delay of growth. The application of the Seoane and Latham criteria showed that most infants had acute malnutrition, but chronic malnutrition was already present in 11.0% of the infants followed-up. The results of this study show the negative impact of an unfavorable environment on infants during their first year of life.

[Cidade Leonor slum, São Paulo. III. Environmental contamination and natural feeding practice]. / Observações sobre a favela da Cidade Leonor, São Paulo. III--Contaminação ambiental e a prática do aleitamento natural.

In this study the authors report the high rate of environmental contamination to which children living in slum areas are exposed. The authors performed a bacteriologic and parasitologic survey in children with acute diarrhea and in controls. Feeding habits were also recorded. The feeding habits revealed that 176 out of 520 children (33.8%) were never breast fed, whereas the remaining 344 (66.7%) were breast fed for an average of 2.2 months. The parasitologic survey was positive in 89% of the stool samples obtained from 83 children, mostly with multiple infections. The bacteriologic survey revealed the presence of enteropathogens and, in particular, invasive E. coli and Campylobacter in 46.7% of the children with acute diarrhea, and in 32.5% of the children in the control group. These findings allow the authors to state that environmental conditions of slum areas directly predispose to the appearance of the diarrhea-malnutrition binomial.

[Cidade Leonor slum, São Paulo. I. Evaluation of the nutritional status of children under 10 years of age]. / Observações sobre a favela da Cidade Leonor, São Paulo. I--Avaliação do estado nutricional das crianças menores de 10 anos.

The authors studied the nutritional status of 520 children living in slums in the City of São Paulo. The weight-for-age index revealed the following results: eutrophy, 46.9%; PCM I, 42.8%; PCM II, 9.9%; PCM III, 1.1%. The height-for-age index revealed the following results: eutrophy, 65.7% and PCM 34.2%. The weight-for-height index revealed the following results: eutrophy, 79.0%; PCM I, 15.9%; PCM II, 3.4%; PCM III, 1.5%. According to the Seoane-Latham criteria the authors found the following results: eutrophy, 43.1%; balanced chronic malnutrition, 19.0%; acute malnutrition, 24.6%; evolutive chronic malnutrition, 9.2%; and chronic malnutrition in recovery 4.0%.