Children who live in inadequate environmental conditions are at risk of bacterial overgrowth and methane production. Hydrogen is a substrate for methane production in the colon.

Objective: To determine the number of lactobacillus and bifidobacterium colonies in the feces of schoolchildren from two different socioeconomic levels. Methods:We analyzed fecal samples of children aged 6 to 10 years without gastrointestinal symptoms or recent use of antimicrobials. The first group included 86 children living in a favela in the city of Osasco, state of São Paulo, southeastern Brazil. The second group included 36 children attending a private school in the same city. Body mass index (BMI) was used to assess nutritional status according to the reference values of the National Center for Health Statistics (NCHS). Specific anaerobic culture media were used for isolation of colonies for 48 and 72 hours at 37 °C. The number of colonies was determined using the plate-counting method. Results:The mean lactobacillus (1.125 x 10 9 colony-forming units, CFU/g) and bifidobacterium (1.675 x 10 9 CFU/g) counts in the private school group were higher (p < 0.001) than those in the favela group: 0.250 x 10 9 and 0.350 x 10 9 CFU/g, respectively. In the favela group, children with BMI z score < -1.0 standard deviation (SD) (n = 28) showed lower mean (p < 0.05) lactobacillus (0.100 x 10 9 CFU/g) and bifidobacterium (0.095 x 10 9 CFU/g) counts than the children with BMI ≥ -1.0 SD (n = 57): 0.350 x 10 9 and 0.420 x 10 9 CFU/g, respectively. Conclusion:The microbiota of schoolchildren living in unfavorable environmental conditions shows lower numbers of fecal lactobacillus and bifidobacterium colonies, especially in children with lower BMI values.J Pediatr (Rio J). 2009;85(4):307-314: Lactobacillus, bifidobacterium, socioeconomic factors, nutritional status, environmental exposure, enteropathies. ResumoObjetivo: Determinar o número de colônias de lactobacilos e bifidobactérias nas fezes de crianças escolares, pertencentes a dois estratos socioeconômicos.Métodos: Foram analisadas amostras de fezes de crianças com idade entre 6 e 10 anos sem sintomas gastrointestinais ou uso recente de antimicrobianos. O primeiro grupo foi constituído por 86 crianças, moradoras em uma favela localizada no município de Osasco (SP). O segundo grupo foi constituído por 36 crianças matriculadas em uma escola particular da mesma cidade. O estado nutricional foi avaliado usando o índice de massa corporal (IMC) de acordo com os valores de referência do National Center for Health Statistics (NCHS). O isolamento das colônias foi realizado em meios de cultura específicos em anaerobiose, durante 48 e 72 horas a 37 °C. A determinação do número foi feita pelo método da contagem em placa.Resultados: A mediana de lactobacilos (1,125 x 10 9 unidades formadoras de colônia, UFC/g) e bifidobactérias (1,675 x 10 9 UFC/g) na escola particular foi superior (p < 0,001) ao do grupo da favela: 0,250 x 10 9 e 0,350 x 10 9 UFC/g, respectivamente. No grupo da favela, crianças com escore z de IMC < -1,0 desvio padrão (n = 28) apresentaram menor mediana (p < 0,05) de lactobacilos (0,100 x 10 9 UFC/g) e bifidobactérias (0,095 x 10 9 UFC/g) em relação às cria...

Objective: To determine the number of lactobacillus and bifidobacterium colonies in the feces of schoolchildren from two different socioeconomic levels. Methods:We analyzed fecal samples of children aged 6 to 10 years without gastrointestinal symptoms or recent use of antimicrobials. The first group included 86 children living in a favela in the city of Osasco, state of São Paulo, southeastern Brazil. The second group included 36 children attending a private school in the same city. Body mass index (BMI) was used to assess nutritional status according to the reference values of the National Center for Health Statistics (NCHS). Specific anaerobic culture media were used for isolation of colonies for 48 and 72 hours at 37 °C. The number of colonies was determined using the plate-counting method. Results:The mean lactobacillus (1.125 x 10 9 colony-forming units, CFU/g) and bifidobacterium (1.675 x 10 9 CFU/g) counts in the private school group were higher (p < 0.001) than those in the favela group: 0.250 x 10 9 and 0.350 x 10 9 CFU/g, respectively. In the favela group, children with BMI z score < -1.0 standard deviation (SD) (n = 28) showed lower mean (p < 0.05) lactobacillus (0.100 x 10 9 CFU/g) and bifidobacterium (0.095 x 10 9 CFU/g) counts than the children with BMI ≥ -1.0 SD (n = 57): 0.350 x 10 9 and 0.420 x 10 9 CFU/g, respectively. Conclusion:The microbiota of schoolchildren living in unfavorable environmental conditions shows lower numbers of fecal lactobacillus and bifidobacterium colonies, especially in children with lower BMI values.J Pediatr (Rio J). 2009;85(4):307-314: Lactobacillus, bifidobacterium, socioeconomic factors, nutritional status, environmental exposure, enteropathies.