Comparison of the effects of different nutrient media on production of heat-stable enterotoxin-b by Escherichia coli.
Vet Microbiol
; 144(1-2): 160-5, 2010 Jul 29.
Article
en En
| MEDLINE
| ID: mdl-20097018
ABSTRACT
Trypticase soy broth (TSB) has been commonly used to culture Escherichia coli strains for detection or harvest of heat-stable enterotoxin-b (STb); however, in our experience, the yields have been low. In this study, we compared STb yields resulting from growth in brain heart infusion broth (BHI) supplemented with 2% casamino acids (BHI-CA) with that from TSB. Since strains may concurrently express heat-labile enterotoxin (LT) and lincomycin has been reported to cause increased expression of LT, we also compared its effects on STb production. STb(+) clones had significantly higher production of STb when grown in BHI-CA compared to TSB, based on enzyme-linked immunosorbent assay (ELISA) conducted on cell-free supernatants. The superiority of BHI-CA to TSB was further tested on 17 porcine enterotoxigenic E. coli (ETEC) isolates, all positive for the STb gene (estB) by PCR. Cell-free supernatants of 100% of the ETEC isolates were detectably positive for STb by ELISA when grown in BHI-CA, in contrast to only 10 strains positive (59%) when TSB supernatants were analyzed. For all the samples, the amounts of STb expressed in BHI-CA based on ELISA were significantly higher than those from TSB (p
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1
Bases de datos:
MEDLINE
Asunto principal:
Proteínas de Escherichia coli
/
Escherichia coli
Límite:
Animals
Idioma:
En
Revista:
Vet Microbiol
Año:
2010
Tipo del documento:
Article
País de afiliación:
Estados Unidos