Crecimiento postnatal inicial de lactantes prematuros nacidos en Chillán de acuerdo a residencia urbana o rural / Postnatal growth of low birth weight infants born in Chillán according with urban or rural residence

Se estudio la asociación entre la residencia rural o urbana y el crecimiento inicial de lactantes nacidos pretérmino (AEG) en el Hospital Herminda Martín de Chillán, Chile. Se estudiaron prospectivamente hasta los 4 meses de vida, 80 lactantes nacidos entre enero y septiembre de 1995 (35 urbano y 45 rural), con peso de nacimiento <2 500 g y edad gestacional < 36 semanas. En los consultorios de atención primaria donde se controlaron se aplicó encuesta socioeconómica a la madre y se registro mensualmente peso y talla. Los niños rurales tendieron a crecer menos que los urbanos en los primeros 4 meses (13,6 vs, 14,4 cm, ns). En ambos grupos el menor crecimiento se asoció con estatura materna < 1,55 m (p< 0,0009). Entre los nacidos con más de 2 000 g los rurales crecieron menos en talla que los urbanos (12,7 vs 15,4 cm p < 0,0002). Concluimos que los lactantes nacidos prematuros en Chillán, de procedencia rural, tienen un menor crecimiento que los urbanos ya desde los primeros meses de vida

Escherichia coli: diversidad de fenotipos bioquímicos en ambientes acuáticos (Santa Fe, Argentina) / Escherichia coli: diversity of biochemical phenotypes in aquatic environments (Santa, Fe, Argentina)

During certain environmental conditions, the floating aquatic vegetation, mainly represented by Eichhornia crassipes (water hyacinth) invade and even cover water courses assigned to recreational activities or to the supply of drinkable water. The rhizosphere of these plants constitutes an unknown biotope of bacteria of sanitary interest, possibly different from waters without vegetation and of the sediment of the same aquatic system. To verify such possibility, 206 isolated strains in MacConkey Agar (Difco) were typified and identified (78 from water, 65 from sediment and 63 from rhizosphere) using the API 20 E system (v. 4.0) and Apilab plus software (v 3.3.3), both of bioMÚrieux (Marcy-l'Etoile, France, 1998). Nineteen different biochemical phenotypes from E. coli were found. The 79 of the population belonged to only 7 phenotypes; the 21 remaining, to the other 12 phenotypes. Twelve phenotypes did not share the biotopes, while only 4 were in the three. These results (and those obtained by other authors who used the API 20 E system in other biotopes) suggest that it would be possible to characterize the rhizosphere using those phenotypes that are found in smaller proportion. The greatest index of diversity (H) and evenness (E) were found in the rhizosphere (H = 2.903; E = 0.874). The dendrogram (average distances and UPGMA method) reaffirms the dissimilarity in biochemical phenotypes of E. coli populations of the rhizosphere with regard to the other biotopes. The most abundant bacterial species in the three biotopes were E. coli, Klebsiella terrigena and K. pneumoniae, corresponding to 75.2 of the community. The rhizosphere differed from Serratia odorifera and from Klebsiella spp. because of its higher rate of isolation.