Viabilidad de un aislado de Escherichia coli O157:H7 en queso tipo Guayanés usando separación inmunomagnética como herramienta de recuperación

• Main Authors: Rojas Tomás, Peñuela Ana, Pernía Giliana, Perdomo Mónica, Gil Marielsa, Reyes Doris
• Format: Article in Journal/Newspaper
• Language: English; Spanish
• Published: Universidad del Zulia,Facultad de Medicina,Departamento de Enfermedades Infecciosas y Tropicales 2009
• Subjects: Escherichia coli O157:H7; Separación inmunomagnética; Queso; immunomagnetic separation; cheese; Arctic medicine. Tropical medicine; RC955-962; Public aspects of medicine; RA1-1270; Arctic
• Online Access: https://doaj.org/article/7e230558bb3e40858782f6c7eb0ba751

Abstract: The viability of an Escherichia coli O157:H7 strain in cottage-industry Guayanes cheese was determined by evaluating several isolation protocols based on immunomagnetic separation (IMS). Cheese units (25 g) were inoculated with 25 and 250 cel/g of this pathogen and stored at 4°C. The pieces were analized at 0, 2, 6, 8 and 10 days post-inoculation through several IMS protocols including two enrichment broths: buffered peptone water without inhibitors (BPW-WI) and buffered peptone water with vancomicyn, cefixime and telurite (BPW-VCT) and two immunoseparation isolation agars: MacConkey-sorbitol agar (MSA) and MacConkey-sorbitol agar with cefixime and telurite (MSA-CT). Results demonstrated the viability of the pathogen for up to 10 days post-inoculation, and during this time, for some of the schemes applied on the IMS base, an increase in recovery percentages was achieved, indicating that the number of inoculated cells increased with time. In terms of the utility of IMS for recovering the pathogen, variations in the isolation percentages were observed in terms of the enrichment broth and the level of inoculated cells. The biggest recovery percentages were obtained in pieces inoculated with 250 cel/g, with ranges between 35 and 85% (days 0 and 10 respectively) in the best IMS scheme (BPW-WI/IMS/MSA), while, at levels of 25 cel/g, in the best case (BPW-WI/IMS/MSA), 15% was not surpassed during the first six days. The best performing enrichment broth was BPW-WI (p<0.05) and differences in the recovery percentages (p>0.05) were not observed in relation to the agars (MSA and MSA-CT) used for sowing the immunoseparator. Resumen: Se determinó la viabilidad de Escherichia coli O157:H7 en queso guayanés de manufactura artesanal, evaluando distintos esquemas de aislamiento basados en separación inmunomagnética (SIM). Unidades de queso (25 g) fueron inoculadas con 25 y 250 cel/g del patógeno y almacenadas a 4°C. Las piezas se analizaron los días 0, 2, 6, 8 y 10 post-inoculación a través de distintos esquemas ...