Artículos de revistas
Serotypes, virulence genes, and intimin types of Shiga toxin-producing Escherichia coli (STEC) and enteropathogenic E-coli (EPEC) isolated from calves in Sao Paulo, Brazil
Registro en:
International Journal Of Food Microbiology. Elsevier Science Bv, v. 115, n. 3, n. 297, n. 306, 2007.
0168-1605
WOS:000245772700005
10.1016/j.ijfoodmicro.2006.10.046
Autor
Aidar-Ugrinovich, L
Blanco, J
Blanco, M
Blanco, JE
Leomil, L
Dahbi, G
Mora, A
Onuma, DL
Silveira, WD
de Castro, AFP
Institución
Resumen
Shiga toxin-producing Escherichia coli (STEC), is the most important recently emerged group of foodborne pathogens. Ruminants, especially cattle, have been implicated as a principal reservoir of STEC, undercooked ground beef and raw milk being the major vehicles of foodborne outbreaks. Enteropathogenic E. coli (EPEC) strains are defined as eae-harboring diarrheagenic E. coli that possess the ability to form A/E lesions on intestinal cells and that do not possess Shiga toxin genes. In order to determine the occurrence, serotypes and virulence markers of STEC and EPEC strains, 546 fecal samples from 264 diarrheic calves and 282 healthy calves in beef farms in Sao Paulo, Brazil, were screened by PCR. STEC and EPEC were isolated in 10% and 2.7% of the 546 animals, respectively. Although IMS test was used, the STEC serotype O157:H7 was not detected. The most frequent serotypes among STEC strains were O7:H10 0022:H16, 011:H(-), 0119:H(-) and 0174:H21, whereas 026:H11, 0123:H11 and 017:H11 were the most prevalent among EPEC strains. In this study, serotypes not previously reported were found among STEC strains: 07:H7, 07:H10, 048:H7, 0111:H19, 0123:H2, 0132:H51, 0173:H(-), and 0175:H49. The eae gene was detected in 25% of the STEC and 100% of EPEC strains. The intimin type 0/,gamma 2 was the most frequent among STEC, whereas the intimin beta 1 was the most frequent intimin type among EPEC strains. To our knowledge, this is the first report of the occurrence of the new intimin mu B in one strain of animal origin. This new intimin was detected in one atypical EPEC strain of serotype 0123:H? isolated from diarrheic cattle. The enterohemolysin (ehxA) was detected in 51% of the STEC and 80% of the EPEC strains, whereas STEC autoagglutinating adhesin (saa) virulence gene was detected only in those STEC strains negative for eae gene. All 15 bovine EPEC strains isolated in this study were negative for both eaf and bfp genes. Our data shows that in Brazil cattle are not only a reservoir of STEC and atypical EPEC, but also a potential source of infection in humans, since the important STEC serotypes previously described and associated with severe diseases in humans, such as 0111:H(-), 0113:H21, 0118:H16, and 0174:H21 were isolated. (c) 2007 Elsevier B.V. All rights reserved. 115 3 297 306