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Survival of Escherichia coli O157:H7 transformed with either the pAK1-lux or pXEN-13 plasmids in in vitro bovine ruminal and fecal microbial fermentations

Permanent URL:
http://handle.nal.usda.gov/10113/58272
Abstract:
The use of luminescent plasmids in bacteria may serve as a viable model for the real-time validation of various pre-harvest interventions on the colonization or shedding patterns of Escherichia coli O157:H7 within cattle. The objective of this study was to determine if the growth characteristics of E. coli O157:H7 in mixed ruminal and fecal microbial fluid cultures would be altered when transformed with one of the two luminescent plasmids:pAK1-lux (PAK) or pXEN-13 (XEN). Transformants harboring the luminescent plasmids were compared to the non-transformed parental strain (wild type [WT]) after incubating in mixed ruminal or fecal microbial fluid media for 6 h in triplicate (n = 3). The transformants and WT exhibited similar growth rates. Within mixed ruminal microbial fluid fermentations and mixed fecal microbial fluid, all transformants grew similarly ( p = 0.28) through the 6-h study. The reflective light unit (RLU; photons/pixel per second) photonic emissions of each plasmid within ruminal fluid differed at 0 h ( p = 0.002) and 2 h ( p = 0.02) and within fecal fluid at 0 h ( p = 0.009) and 2 h ( p = 0.04). The RLU remained the same within rumen fluid at 4 h ( p = 0.22) and 6 h ( p = 0.80) and within fecal fluid at 4 h ( p = 0.06) and 6 h ( p = 0.29). Growth of E. coli O157:H7 transformed with the bioluminescent plasmids was not altered in comparison to the WT, suggesting that both plasmids may serve as useful models for in vivo studies.
Author(s):
Heather A. Duoss , Janet R. Donaldson , Todd R Callaway , Jeffery A. Carroll , Paul R. Broadway , James M. Martin , Sara Shields-Menard , Ty B. Schmidt
Subject(s):
Escherichia coli O157 , bacteria , cattle , genetic transformation , in vivo studies , microbial growth , models , pathogen survival , plasmids , rumen , rumen fermentation , shedding
Source:
Foodborne pathogens and disease 2013 v.10 no.1
Language:
English
Year:
2013
Collection:
Journal Articles, USDA Authors, Peer-Reviewed
File:
Download [PDF File]
Rights:
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.