Recombinant Phage Probes for Salmonella Typhimurium Detection

摘要

Salmonella typhimurium is a leading cause of inadvertent gastrointestinal foodborne illness in the United States. Although few actual accounts of deliberate food contamination have been documented in the United States, the recent advent of biocrimes and terrorism in our country suggests that this trend will not continue, highlighting the importance of rapidly identifying biological agents, regardless of the contamination origin, as one part of a comprehensive strategic plan to secure the public food supply. There is an urgent need for deployable, real-time threat agent detectors to replace traditional methods of food safety analysis that are slower, labor-intensive, and cost-inefficient. Confirmation of presence in food products can take as long as 48 hours by conventional culture. Current rapid detection initiatives include biosensors that routinely incorporate antibodies as the biorecognition unit. Although sensitive and specific, antibodies are costly and may degrade under unfavorable environmental conditions. We believe that a stable, inexpensive substitute for antibodies is filamentous phage manipulated through phage display technique then affinity selected for specificity to S. typhimurium from billion-clone phage landscape libraries. Our results show that recombinant phage affinity selected against S. typhimurium can be 12,000- 22, 000 times for more specific than controls and 10-1000 times more selective for S. typhimurium than other select enterobacteria. We anticipate that these highly specific, selective phage binders will build upon our current biosensor development initiatives for the rapid detection of biological agents such as S. typhimurium.