RESUMEN
In this study, samples of raw ground beef (n = 150) and fresh sausage (n = 100) were collected randomly from butcheries, supermarkets, and fast-food shops, in Casablanca, Morocco. Two types of meat product samples were considered, one with spices (n = 115) and other without spices (n = 135). All the samples were analyzed for the presence of the following bacteria: Escherichia coli, Staphylococcus, Clostridium perfringens, Salmonella, and Listeria monocytogenes. E. coli strains were further typed by pulsed-field gel electrophoresis (PFGE), Operon O, and characterized for virulence genes by polymerase chain reaction (PCR). Results indicated that counts of E. coli, coagulase-positive Staphylococcus, and C. perfringens were 17%, 9.6%, and 8.7% in samples without spices, respectively; and 23.5%, 23.7%, and 29.6% in samples with spices, respectively. Two pathogenic genes, LT and EAST, were identified separately in four strains of E. coli. Salmonella and L. monocytogenes were isolated in 2.8% and 3.2% of the total samples, respectively.
Asunto(s)
Microbiología de Alimentos , Productos de la Carne/microbiología , Animales , Bovinos , Clostridium perfringens/genética , Clostridium perfringens/aislamiento & purificación , Recuento de Colonia Microbiana , Electroforesis en Gel de Campo Pulsado , Escherichia coli Enterotoxigénica/genética , Escherichia coli Enterotoxigénica/aislamiento & purificación , Conservación de Alimentos , Humanos , Listeria monocytogenes/genética , Listeria monocytogenes/aislamiento & purificación , Marruecos , Reacción en Cadena de la Polimerasa , Staphylococcus aureus/genética , Staphylococcus aureus/aislamiento & purificaciónRESUMEN
Shiga toxin Escherichia coli (STEC), also called verotoxin-producing E. coli, is a major cause of food-borne illness, capable of causing hemorrhagic colitis and hemolytic-uremic syndrome (HUS). This study was carried out to evaluate the presence of (STEC) and E. coli O157:H7 in shellfish and Mediterranean coastal environments of Morocco. The contamination of shellfish and marine environment with Shiga toxin-producing E. coli (STEC) and E. coli O157:H7, was investigated during 2007 and 2008. A total of 619 samples were analyzed and 151 strains of E. coli were isolated. The presence of the stx1, stx2, and eae genes was tested in E. coli isolates strains using a triplex polymerase chain reaction. STEC was detected in three positives samples (1.9%), corresponding to the serotype O157:H7, the others Shiga toxin-producing E. coli non-O157 were also detected.
Asunto(s)
Mariscos/microbiología , Escherichia coli Shiga-Toxigénica/aislamiento & purificación , Escherichia coli Shiga-Toxigénica/metabolismo , Animales , Proteínas de Escherichia coli/genética , Marruecos , Reacción en Cadena de la Polimerasa Multiplex , Escherichia coli Shiga-Toxigénica/genética , Factores de Virulencia/genéticaRESUMEN
In order to develop other molecular method useful for typing of motile and non motile Escherichia coli strains, a total of 207 strains of E. coli (133 reference strains, 74 food strains) were characterized by analysis of sequences of their amplified flagellin-encoding (fliC) gene products. The collection of reference strains was used for database building of fliC gene sequences. Application of this identification system to 74 E. coli food isolates revealed a reproducible and clear cut classification with very good correlation to results obtained by HhaI restriction of the amplified flagellin gene. The proposed determination of fliC sequences variations should be helpful for epidemiological studies.