RESUMO
Se ha investigado, mediante estudios de cinética de muerte celular, el efecto inhibidor de una cepa de Lactobacillus casei, aislada de un alimento cárnico fermentado producido en la región santafesina (Argentina), y de su sobrenadante libre de células (SLC), frente a tres cepas de Escherichia coli O157:H7. La cepa de L. casei 206/1 se seleccionó sobre la base de resultados obtenidos en estudios previos donde, aplicando la técnica de agar spot, se determinó que su SLC produjo el mayor efecto inhibitorio sobre E. coli O157:H7. En los ensayos de cinética de muerte celular se observó una reducción significativa de las cepas de E. coli O157:H7 estudiadas, tanto en cocultivos como en el ensayo con el SLC, no detectándose bacterias viables luego de 24 horas de incubación. Estos resultados demuestran que cepas de bacterias ácido lácticas aisladas a partir de un determinado ecosistema regional, pueden convertirse en una herramienta biotecnológica útil para controlar a E. coli O157:H7 en alimentos.
Through the study of cell death kinetics, we have analyzed the inhibiting effect of a Lactobacillus casei strain isolated from a fermented meat product produced at the Santa Fe region in Argentina, and of its cell-free supernatant (CFS), against three Escherichia coli O157:H7 strains. The L. casei 206/1 strain was selected on the basis of results obtained in previous studies where using the agar spot technique, it was determined that CFS produced the greatest inhibitory effect over E. coli O157:H7. The studies of cell death kinetics showed a significant reduction of the E. coli O157:H7 strains tested, both in cocultures and in assays with CFS, and no viable bacteria were detected after 24-hours of incubation. These results show that lactic acid bacterial strains isolated from a determined regional ecosystem, can become a useful biotechnological tool for controlling E. coli O157:H7 in food.
RESUMO
The early detection of anti-CagA antibodies in young adults would be of a great clinical impact in the prevention of gastric cancer. The aim of this study was to assess IgG and anti-CagA antibodies seroprevalence against Helicobacter pylori in our region using a non invasive technique, easy to perform an evaluating its relationship with different epidemiological risk factors. Four hundred and thirty-five volunteers with a mean age of forty years old from different health centers were included in this study. Demographic socieconomical and other data of interest were recorded. IgG and CagA antibodies against Helicobacter pylori were determined using an enzyme immunoassay technique. The prevalence of IgG antibodies was 52.2% being 152 in women (53.7%) and 75 in men (49%). These antibodies were showed in 65% of affected patients and 43.1% in asymptomatic carriers. The prevalence anti-CagA antibodies was 63.4% among seropositives (IgG) individuals corresponding to 33.1% of the total studied population. Ninety-six (33.9%) persons of this group were women an 48 (31.6%) were men. The prevalence was 45.4% and 25.7% in symptomatic an asymptomatic individuals, respectively. It was demonstrated that IgG antibodies were associated with age, area of residence, educational level reached and number of bedrooms in the house. The anti-CagA antibodies depend on area of residence and symptoms. The relation between the symptoms and the presence of anti-CagA antibodies shows the selective importance of clinical data in the gastric diseases associated with Helicobacter pylori.