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Escherichia coli subtypes EPEC, ETEC, EAEC, EHEC, EIEC, and DAEC in acute diarrhea ECEP, ECET, ECEA, ECEH, ECEI, ECAD: a E. coli revisitada no contexto da diarréia aguda Aderbal Sabrá J Pediatr (Rio J) 2002;78(1):5-6 The diarrhea syndrome is one of the most important causes of morbidity and mortality in children worldwide, as related to the local aspects of prevalence and pathogenesis. On the one hand, in poorer regions -- where the purchasing power of the population is low, and where households are neither connected to water nor sewer systems -- either in the outskirts of large urban centers or in slum areas (favelas), the infant mortality rate is sometimes higher than 100 per 1,000 livebirths; in these cases, diarrhea is responsible for over 50% of deaths and is caused mainly by bacteria. On the other, in urban regions -- where the population presents higher levels of schooling and of purchasing power and where households are connected to both water and sewer systems -- the infant mortality rate is lower than 20 per 1,000 livebirths and diarrhea is responsible for less than 1% of deaths. What is more, virus, and not bacteria, is the main agent causing diarrhea (1). Brazil is a country of continental proportions. It has rich and industrialized regions surrounded by clusters of extreme poverty. This situation puts, side-by-side, a population of highly educated individuals who enjoy a high degree of comfort afforded by the advancements of the 21st century and a population of poor individuals who have no access to education, hygiene, or water systems. While the first population has an average income per head higher than 20 Brazilian minimum wages and lives in urban areas and connected to water systems, the second population, in turn, has an average income per head of less than one minimum wage and households (if there is one) are, literally, located in the gutter with sewage flowing in front of their doorstep. This paradox describes the current situation in our country, with extreme poverty on the one hand and overflowing wealth on the other. In this sense, the task of assessing the situation of acute diarrhea and its agents is a difficult one, since most Brazilian children live in intermediate conditions, as is the case of most developing countries. The first step for the characterization of the agent causing diarrhea is identification. Isolating the infectious agent is thus fundamental. Currently we can rely on cultures in selected media, on antigen stimulation, on specific radioimmunoassays, on fiber-optic and electronic microscopy for direct visualization of the agent, and on specific tests for the identification of pathogenic strains. In this sense, professor Okay and colleagues present one of the most comprehensive works, especially with respect to the role of E. coli in acute diarrhea. The identification of a bacterial or viral agent causing acute infectious diarrhea is important, but does not determine the etiologic diagnosis considering the possibility of the carrier being healthy and the possible associations of isolated pathogens in fecal samples, as shown in the work of Yassuhiko Oaky et al. (2). Consequently, it is necessary to obtain an agreement between the agent causing diarrhea and the laboratory findings, which would indicate that the acute crisis has the same physiopathogenesis. The use of these elements combined (etiologic isolation and laboratory) allows for the elimination of etiological associations or false-positives. Currently, it is wellknown that for every agent there is a well-defined physiopathology that causes specific laboratory alterations. This sort of deeper laboratory detailing would have enhanced Dr. Eloísa Souza's work, and would have also indicated the main pathogen among the isolates found in the associations. In the case of viral diarrhea, it is important to observe that there is an agreement between abnormalities in negative blood and leukocytes, low fecal sodium, and positive virus laboratory tests. The alterations in abnormal elements are explained by the physiopathology of the viral aggression, in which case it is well-known that osmotic phenomena are a result of the severe epithelial lesion, with fecal sodium presenting values below normal (3-5). In infectious, toxigenic diarrheas there is an overall prevalence of very high fecal sodium in patients with high volumes of watery diarrhea. In this case there are no abnormal elements; rather, there is an active secretion of chlorine and an absence of reabsorption of sodium, which is lost in the feces (6). In the case of invasive, infectious diarrhea caused by bacteria, patients will present blood in feces, and abnormal elements positive for leukocytes and red blood cells as well as fecal sodium of approximately 40 to 70 mEq/l. Negative leukocytes indicate EHEC, whereas negative leukocytes and red blood cells, EPEC (7). The data related to the isolated agents causing diarrhea (virus or bacteria) allows us to assess the etiopathogenesis and the understanding of the physiopathological mechanism. In addition to their great diagnostic value, these findings indicate the correct rehydration therapy especially as to what concerns the management of sodium in oral hydration. Diarrhea with elevated fecal sodium dehydrates patients, who in turn can only be rehydrated with high sodium concentration oral solutions, as indicated by the World Health Organization (WHO). Consequently, solutions with 60 or less mEq/l will fail in the rehydration of toxigenic diarrhea. Solutions of 90 or greater mEq/l, in turn, can lead young infants to hypernatremia in cases of viral diarrhea (low fecal loss of sodium) (5). Though there are several studies on the etiology of acute infectious diarrhea, few have carried out a comprehensive evaluation on all pathogenic agents, such as the case of the study carried out by the Pediatric Department of the teaching hospital of the Universidade de São Paulo in a population of low social and economical status from the district of Butantã, in São Paulo. In this location, acute diarrhea is the second most important cause of medical appointments and hospitalization in the past five years. Thus, it is important that a comparison be carried out considering the findings reported in the literature in the past 40 years (8-10). Acute infectious diarrhea in developing countries (10)

Author

Sabrá et al.

Muños et al.

Stall et al.

Mata et al.

Trabulsi et al.

Kitagawa et al.

Gerrant et al.

Country

Brazil

Mexico

Bangladesh

Costa Rica

Brazil

Brazil

Brazil

City

Rio de Janeiro

Mexico

Dacca

San José

São Paulo

São Paulo

Ceará (state)

Year

1977-1978

1971-1979

1979-1980

1976-1981

1979-1982

1982

1983

Rotavirus

30

17.1

19.4

45.3

n

9.6

19.4

ETEC

22

7,1

20.0

14.3

13

7.1

20.8

EPEC

15

n

n

n

25.8

21.1

4.6

EIEC

1

0.6

n

n

1.2

1.3

2.0

Salmonella

19

12.1

0.6

7.3

7.2

6.0

n

Shiguella

5

13.6

11.6

8.1

5.9

6.6

8.0

Campylobacter

5

10.0

11.6

8.1

6.0

5.4

n

Yersínia

2.5

4.0

n

n

0.6

n

n

Vibrio C

n

n

5.5

n

n

n

n

Entamoeba h

n

2.1

6.1

n

n

n

2.0

Giardia

n

1.8

5.6

4.5

n

n

6.7

not identified

0.5

31.6

19.6

12.4

40.3

42.9

36.5

n = not investigated Different studies carried out in different cities for the past 40 years, which have in common the characteristic of populations from underdeveloped, poor areas, show similarities with the study presented by the group lead by professor Okay (11). The rotavirus agent was the most frequent pathogen identified, with incidences varying from 17.1% in Mexico to 45.3% in Costa Rica. In the referred study, rotavirus appeared separately in 20.8% of cases studied; considering also the associations with other agents, rotavirus was identified in 34.9% of patients. ETEC was the most prevalent bacteria reported in the literature in the past few decades for populations of low economical status. The poorer the population, the more prevalent the ETEC. In São Paulo, in the previous studies by Trabulsi and Kitagawa and in the current study, EPEC was more prevalent. As to the presence of invasive bacteria, the studies carried out in Rio de Janeiro indicated a prevalence of Salmonella whereas in other previous studies and in the current study, the more prevalent agent was Shiguella. Campylobacter, EHEC, Yersinia, and EIEC are, in that same order, more prevalent worldwide (12,13). It should be underscored that the work of Dr. Eloísa Souza et al. shows a detailed study of the role of E. coli in acute diarrhea in poor populations of the state of São Paulo. In my understanding, this is a result of the influence of the eminent scientist and professor Luiz Rachid Trabulsi, a pioneer in the studies related to the role of EPEC in acute diarrhea in Brazil. In this sense, I would like to salute the scientist and congratulate all those who participated in this excellent etiopathogenic review on acute diarrhea in São Paulo, lead by Professor Okay. Aderbal Sabrá - Professor, Clinical Practice for Children and Adolescents, UNIGRANRIO; Member, National Academy of Medicine Top | Close References Title of the article: "Escherichia coli subtypes EPEC, ETEC, EAEC, EHEC, EIEC, and DAEC in acute diarrhea" 1. Sabrá A. Diarréia Aguda e Crônica em Pediatria. 4ª ed. Rio de Janeiro: Ed. Cultura Médica; 1994.p.93. 2. Souza EC, Martinez MB, Taddei CR, Mukai L, Gilio AE, Racz ML, et al. Perfil etiológico das diarréias agudas de crianças atendidas em São Paulo. J Pediatr (Rio J) 2002;78(1):31-38. 3. Wrong O, Metcaff -Gibson A. The electrolyte content of feces. Proc Roy Soc Med 1965; 58: 1007. 4. Kerzner B, Kelly M, Gall D, Butler D, Hamilton J. Transmissible gastroenteritis - sodium transport and the intestinal epithelium during the course of viral enteritis. Gastroenterology 1977; 72:457. 5. Sabrá A. Diarréia Aguda e Crônica em Pediatria. 4ª ed. Rio de Janeiro: Ed. Cultura Médica; 1994.p.110. 6. Sharp C, Hynie S. Stimulation of intestinal adenyl cyclase by cholera toxin. Nature 1971; 229: 226. 7. Sabrá A. Diarréia Aguda e Crônica em Pediatria. 4ª ed. Rio de Janeiro: Ed. Cultura Médica; 1994.p. 97. 8. Guerrant RL, Hughes JM, Lima NL, Crane J. Diarrhea in developed and developing countries: magnitude, special setting, and etiologies. Rev Infect Dis 1990; 12(S):41. 9. Kitagawa SMS, Toledo MRF, Trabulsi LR, et al. Etiologia da diarréia infecciosa endêmica da criança de baixo nível sócio-econômico em São Paulo. Am J Trop Med Hyg 1986; 35:1013. 10. Sabrá A. Diarréia Aguda e Crônica em Pediatria. 4ª ed. Rio de Janeiro: Ed. Cultura Médica; 1994.p.104. 11. Silva LR. Diarréia aguda em crianças. 1ª ed. Rio de Janeiro: Ed. Medsi; 1988; 73. 12. Stumph M, Ricciardi ID, Oliveira N, Sabrá A, Bernhoeft M. Yersinia enterocolítica as a cause of infantile diarrhoea in Rio de Janeiro. Rev Bras Pesq Med Biol 1979; 11: 383. 13. Ricciardi ID, Ferreira MCS, Otto SS, Oliveira N, Sabrá A, Fontes CF. Thermophilic Campylobacter - Associeted Diarrhea in Rio de Janeiro. Rev Bras Pesq Med Biol 1979; 12: 189. Top | Close Contact us Copyright Sociedade Brasileira de Pediatria © 2001 - All rights reserved All services in this site are free. This is possible thanks to a donation given by Nestlé Infants Nutrition

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Jornal de Pediatria - Print page

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