RESUMEN
The genomic content of Enterobacter sakazakii strain ATCC BAA-894 was analyzed for variable-number tandem repeats (VNTRs). In this study we report the development of a multiple-locus VNTR analysis (MLVA) strategy for the subtyping of E. sakazakii. The method is based on a GeneScan analysis of four VNTR loci labeled with multiple fluorescent dyes. This approach was applied to a collection of 112 isolates representing all 16 of the currently defined E. sakazakii biogroups. MLVA successfully discriminated among these isolates and compared favorably with pulsed-field gel electrophoresis. The method was relatively fast and easy to perform. The potential value of MLVA as an epidemiological tool is discussed.
Asunto(s)
Cronobacter sakazakii/clasificación , Cronobacter sakazakii/genética , Variación Genética , Genómica/métodos , Repeticiones de Minisatélite/genética , Secuencia de Bases , Análisis por Conglomerados , Datos de Secuencia Molecular , Análisis de Secuencia de ADN , Especificidad de la EspecieRESUMEN
Enterobacter sakazakii (E. sakazakii) is an opportunistic pathogen and the aetiological agent in rare but life-threatening cases of meningitis, necrotizing enterocolitis, and sepsis in infants. Among infants, those at greatest risk are neonates (<28 days), particularly those born prematurely or of low birth weight (<2500 g). Consumption of contaminated powdered infant formula (PIF) has been epidemiologically linked with cases of infection. Contamination can occur during the manufacturing process or during postmanufacture reconstitution of formula. Development of rapid, sensitive and specific detection methods will facilitate manufacturers efforts to reduce the occurrence of E. sakazakii in the final powdered product. Furthermore, since PIF is not a sterile product, proper precautions should be taken during handling and reconstitution of formula prior to feeding in order to prevent contamination and proliferation of the bacterium.
Asunto(s)
Enfermedades Transmisibles Emergentes/microbiología , Cronobacter sakazakii , Infecciones por Enterobacteriaceae/microbiología , Enfermedades Transmisibles Emergentes/transmisión , Cronobacter sakazakii/aislamiento & purificación , Cronobacter sakazakii/patogenicidad , Infecciones por Enterobacteriaceae/transmisión , Microbiología de Alimentos , Humanos , Lactante , Recién NacidoRESUMEN
Enterobacter sakazakii (E. sakazakii) contamination of powdered infant formula (PIF) and its processing environment was monitored between April 2005 and March 2006. The purpose of the monitoring programme was to locate points of contamination, investigate clonal persistence, and identify possible dissemination routes along the processing chain. A total of 80 E. sakazakii isolates were recovered from the manufacturing facility. The overall frequency of isolation of E. sakazakii in intermediate and final product was 2.5%, while specific locations in the processing environment were contaminated at frequencies up to 31%. All E. sakazakii isolates were characterised by pulsed-field gel electrophoresis (PFGE). XbaI macrorestriction digests yielded 19 unique pulse-types that could be grouped into 6 clusters of between 5 and 32 isolates. The formation of large clusters was consistent with the presence of a number of clones in the manufacturing environment. While the majority of isolates were of environmental origin (72.5%), no cluster was confined to one specific location and indistinguishable PFGE profiles were generated from isolates cultured from the manufacturing environment, sampling points along the processing chain and from intermediate and final product. These findings suggest that the manufacturing environment serves as a key route for sporadic contamination of PIF. These data will support the development of efficient intervention measures contributing to the reduction of E. sakazakii in the PIF processing chain.
Asunto(s)
Seguridad de Productos para el Consumidor , Cronobacter sakazakii/aislamiento & purificación , Contaminación de Alimentos/análisis , Microbiología de Alimentos , Industria de Procesamiento de Alimentos/normas , Fórmulas Infantiles , Análisis por Conglomerados , Recuento de Colonia Microbiana , Cronobacter sakazakii/clasificación , Electroforesis en Gel de Campo Pulsado , Microbiología Ambiental , Contaminación de Equipos/prevención & control , Humanos , Lactante , Recién Nacido , Filogenia , PrevalenciaRESUMEN
Enterobacter sakazakii has been associated with life-threatening infections in premature low-birth-weight infants. Contaminated infant milk formula (IMF) has been implicated in cases of E. sakazakii meningitis. Quick and sensitive methods to detect low-level contamination sporadically present in IMF preparations would positively contribute towards risk reduction across the infant formula food chain. Here we report on the development of a simple method, combining charged separation and growth on selective agar, to detect E. sakazakii in IMF. This protocol can reliably detect 1 to 5 CFU of E. sakazakii in 500 g of IMF in less than 24 h.
Asunto(s)
Técnicas Bacteriológicas , Cronobacter sakazakii/aislamiento & purificación , Microbiología de Alimentos , Fórmulas Infantiles , Técnicas Bacteriológicas/instrumentación , Cationes , Recuento de Colonia Microbiana , Cronobacter sakazakii/genética , Cronobacter sakazakii/crecimiento & desarrollo , Cronobacter sakazakii/patogenicidad , Enterobacteriaceae/aislamiento & purificación , Conservación de Alimentos , Humanos , Recién Nacido , Magnetismo , Reacción en Cadena de la Polimerasa , Salmonella/aislamiento & purificaciónRESUMEN
Enterobacter sakazakii represents a significant risk to the health of neonates. This bacterium is an emerging opportunistic pathogen that is associated with rare but life-threatening cases of meningitis, necrotizing enterocolitis, and sepsis in premature and full-term infants. Infants aged <28 days are considered to be most at risk. Feeding with powdered infant formula (PIF) has been epidemiologically implicated in several clinical cases. Infants should be exclusively breast-fed for the first 6 months of life, and those who are not should be provided with a suitable breast-milk substitute. PIF is not a sterile product; to reduce the risk of infection, the reconstitution of powdered formula should be undertaken by caregivers using good hygienic measures and in accordance with the product manufacturer's food safety guidelines.