Presence of enterotoxigenic Staphylococcus aureus in artisan fruit salads in the city of San Luis, Argentina

An increase in the consumption of fruit juices and minimally processed fruits salads has been observed in recent years all over the world. In this work, the microbiological quality of artisan fruit salads was analysed. Faecal coliforms, Salmonella spp, Shigella spp, Yersinia enterocolitica and Escherichia coli O157:H7 were not detected; nevertheless, eleven strains of Staphylococcus aureus were isolated. By multiplex PCR, all isolates showed positive results for S. aureus 16S rRNA gene and 63.6% of them were positive for sea gene. Furthermore, PCR sea positive strains were able to produce the corresponding enterotoxin. Finally, the inactivation of these strains in fruit salads by nisin, lysozyme and EDTA, was studied. EDTA produced a total S. aureus growth inhibition after 60 h of incubation at a concentration of 250 mg/L. The presence of S. aureus might indicate inadequate hygiene conditions during salad elaboration; however, the enterotoxigenicity of the strains isolated in this study, highlights the risk of consumers' intoxication. EDTA could be used to inhibit the growth of S. aureus in artisan fruit salads and extend the shelf life of these products.

Seroprevalencia de infección por virus de la hepatitis B y por virus de la inmunodeficiencia humana en una población de pacientes con múltiples transfusiones en cuatro hospitales, Colombia, Sur América / Seroprevalence of hepatitis B virus and human immunodeficiency virus infection in a population of multiply-transfused patients in Colombia

Introducción. Aunque la transfusión de componentes sanguíneos es una terapia ampliamente utilizada, representa un riesgo de transmisión de agentes infecciosos. Objetivo. Como parte de la iniciativa sobre sangre segura promovida por la Organización Panamericana de la Salud, se realizó un estudio para estimar la seroprevalencia de infección por virus de la inmunodeficiencia humana y virus de la hepatitis B en pacientes con múltiples transfusiones en Colombia. Materiales y métodos. Entre febrero y septiembre de 2003, se llevó a cabo un estudio transversal de 500 pacientes con múltiples transfusiones, seleccionados en cuatro hospitales de las ciudades de Bogotá y Medellín. Las muestras de suero obtenidas se analizaron por inmunoensayo con estuches comerciales. Resultados. La frecuencia de seropositividad para el virus de la inmunodeficiencia humana fue de 1,8%, (IC95% 0,5-3,1). La frecuencia de seropositividad para el virus de la hepatitis B fue de 18,6% (IC95% 15,1-22,1). Los principales factores de riesgo fueron: recibir más de 48 unidades de sangre o componentes, tener diagnóstico de hemofilia, recibir transfusiones por un período mayor de un año, recibir sangre total, tener coinfección por virus de la hepatitis C y haber sido transfundido antes de 1993. Conclusiones. Este es el primer estudio epidemiológico realizado en Colombia con un número significativo de pacientes con múltiples transfusiones. El hallazgo más relevante es la elevada prevalencia de infección por virus de la hepatitis B y virus de la inmunodeficiencia humana observado en la población de hemofílicos, comparado con los otros cuatro grupos de pacientes con múltiples transfusiones.

Introduction. Although the transfusion of blood products is a common therapy, it carries risk of transmission of infections, especially hepatitus B virus (HBV) and human immunodeficiency virus (HIV). Objective. As part of the blood safety initiative, the Pan American Health Organization supported studies to estimate the prevalence of human immunodeficiency virus and hepatitis B virus infection in Colombia. Materials and methods. Between February and September 2003, a cross sectional study examined 500 multiply-transfused patients at four hospital centers in the cities of Bogotá and Medellín. The serum samples were analyzed by enzyme immunoassay (EIA) using commercial kits. Results. The seroprevalence of HIV infection was 1.8% (CI 95% 0.5-3.1). The seroprevalence of HBV infection was 18.6% (CI 95% 15.1-22.1). Six risk factors were associated with HIV and HBV infection: (1) receiving more than 48 units of blood or blood components, (2) diagnosis of hemophilia, (3) receiving transfusions for more than one year, (4) receiving whole blood, (5) co-infection with hepatitis C virus and (6) receiving transfusions before 1993. Conclusions. This is the first epidemiological study with a significant sample size performed in multiply-transfused patients in Colombia. The principal finding was the high prevalence of HBV and HIV infection in patients with diagnosis of hemophilia compared with the other five groups of multiply-transfused patients.