Location: Meat Safety and QualityTitle: Isolation and characterization of an Enteropathogen growth stimulating factor from bovine tissues
|OLSTEIN, ALAN - Paradigm Diagnostics, Inc|
|Bosilevac, Joseph - Mick|
|RICHARDSON, ANDREW - Paradigm Diagnostics, Inc|
Submitted to: Journal of Food Protection
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2021
Publication Date: 7/18/2021
Citation: Olstein, A., Bosilevac, J.M., Richardson, A. 2021. Isolation and characterization of an Enteropathogen growth stimulating factor from bovine tissues. [Abstract]. Journal of Food Protection. 84(Suppl A): P. 207.
Technical Abstract: Introduction: In comparative studies using a highly selective medium for Salmonella and Shiga toxin-producing E. coli (STEC), enrichments of ground beef and spinach spiked with low levels of E. coli O157:H7 exhibited 50- to 100- fold increase in STEC recoveries from ground beef compared to spinach enrichments. Purpose: Identify if a soluble component supplied by ground beef may be stimulating the growth of the pathogens. Methods. Suspensions of ground beef were fractionated using ammonium sulfate precipitation and tested for activity. Activity was identified as stimulating STEC and Salmonella growth 5- to 10-fold over controls. Active fractions were affinity purified and analyzed by SDS-polyacrylamide gel electrophoresis (PAGE), with composition of protein bands determined by mass spectrometry analysis of tryptic digests. Candidate compounds were obtained from commercial sources to confirm activity and identity. Results: The ammonium sulfate fractionated ground beef suspensions yielded preparations that markedly stimulated the growth rate and recovery of STEC and Salmonella in both selective (PDX-STEC media) and non-selective (modified Buffered Peptone Water) media by >100-fold and >10-fold, respectively. Affinity purification and SDS-PAGE identified three protein bands of 52-, 35- and 20-kD that each demonstrated growth stimulating activity. The mass spec analysis of the 52- and 35-kD proteins suggested they were 100 % homologous to the glycolytic protein: phosphoglucomutase (E.C. 126.96.36.199 ) and that the 35- and 20-kD proteins were degradation products of the 52kD protein. Commercially prepared rabbit muscle phosphoglucomutase (PGM) used as a reference was shown to have demonstrable growth stimulating activity thereby confirming the identity of the proteins. Significance: Mechanisms of growth stimulation by PGM may be through increasing bacterial fitness and environmental adaptability, thus allowing enhanced recovery and identification of injured pathogens from challenging samples.