Direct detection of toxigenic Bacillus cereus in dietary complement for children and cassava starch

Abstract

<p>Bacillus cereus es un contaminante de alimentos<br />conocido por ser patogénico para los humanos,<br />causando síndromes de vómito y diarrea.<br />En este estudio se evaluó la presencia de B.<br />cereus toxigénicos utilizando PCR múltiple<br />directamente en complementos dietarios<br />para niños y en almidón de yuca colectados<br />en Medellín, Colombia. De 75 muestras de<br />complemento dietario para niños, 70,7%<br />estuvieron contaminadas con B. cereus<br />toxigénicos y se detectaron cuatro diferentes<br />consorcios toxigénicos: I: nheA, hblC, cytK<br />(9,8%), II: nheA, hblC (2%), III: hblC, cytK<br />(41.2%), IV: hblC (47%). De 75 muestras de<br />almidón de yuca, 44% estuvieron contaminadas<br />con B. cereus toxigénicos y se determinaron<br />cuatro diferentes consorcios toxigénicos: I:<br />nheA, hblC, cytK (48.5%), II: nheA, hblC, cytK,<br />cesB (3%), III: hblC, cytK (30,3%), IV: hblC<br />(18.2%). En general, en los complementos<br />dietarios para niños sólo se detectaron<br />consorcios enterotoxigénicos, mientras que en<br />el almidón los consorcios enterotoxigénicos<br />predominaron sobre el emético. La PCR<br />múltiple fue de utilidad para detectar<br />contaminación con B. cereus toxigénicos<br />permitiendo la detección directa y simultánea<br />de todos los genes tóxicos en los alimentos. Este<br />estudio es el primero en Colombia en evaluar B.<br />cereus toxigénicos y proporciona información<br />importante para la evaluación de riesgos<br />microbiológicos en los alimentos pulverizados</p>

Genomic and Toxigenic Heterogeneity of Bacillus cereus sensu lato Isolated from Ready-to-Eat Foods and Powdered Milk in Day Care Centers in Colombia

“…This is a frequent finding (Altayar and Sutherland, 2006) with few exceptions of studies that have found B. cereus emetic strains in various foods (López et al, 2015;Park et al, 2016;Lee et al, 2017;Lin et al, 2017;Mudagza and Buys, 2017;Yang et al, 2017;Frentzel et al, 2018). In Colombia, the cesB gene was detected in DNA directly extracted from cassava starch (Sánchez et al, 2014); however, there are no reports about isolated emetic strains. Probably the reason for this low frequency is because the emetic strains belong to particular lineage of B. cereus s.s. (Økstad and Kolstø, 2011) that may have a low circulation in Colombia; in addition, the cereulide synthetase gene (ces) cluster is harbored on a megaplasmid horizontally transferred, called pBCE (Logan, 2012).…”

“…Knowledge about genomic heterogeneity, including intraspecific diversity and toxigenic profiles of B. cereus, is important to differentiate potential clinical isolates, to find contamination sources, track isolates along the food chain, and elucidate strain distribution within foods (De Jonghe et al, 2008). In Colombia there are reports of the detection of B. cereus enterotoxin genes (hblC, nheA, and cytK2) directly in powdered foods such as dietary complement for children and cassava starch (Sánchez et al, 2014), and of B. cereus strains producing HBL in rice and ready-to-eat cereals (Forero et al, 2018).…”

Enterotoxin Gene Distribution and Genotypes of Bacillus cereus sensu lato Isolated from Cassava Starch

“…Also, a previous study reported the detection of B. cereus s.l. toxin genes in DNA extracted directly from cassava starch [19]. Cassava is a tuberous edible plant from the American tropics [20], and in Colombia, the starch derived from cassava is frequently used for cooking a variety of foods including biscuits, soups and prepared meats such as sausages.…”