Bacteriophage
Bacteriophage are viruses that infect bacteria exclusively.
Bacteriophage (“phage”) possess specific binding elements that recognize very specific structures on the surface of their host bacteria. This high specificity ensures that a given phage infects only its target range of bacteria.
Other bacteria, fungi, yeast, plant, or animals are not affected by the bacteriophage. On binding to its host, the bacteriophage inserts its tail and injects its DNA into the bacteria. This essentially hijacks the replicating mechanisms of the bacteria to make multiple copies of its DNA and the proteins that make up the virus. Final events include lysis (i.e. destruction) of the bacteria and the release of many copies of the bacteriophage, typically 20 -200, depending on the bacteriophage. These released progeny go on to continue the cycle of infection and killing.
The high specificity of bacteriophage is an excellent complement to the high specificity of antibody technology.
SDIX’s proprietary technology (US patent 7,521,201) is applied, for example, in its RapidChek™ SELECT Salmonella, E. coli, and Listeria products.
When present in a food product, pathogenic bacteria (e.g. E. coli, Salmonella, Listeria) typically occur in very small numbers compared to the much larger numbers of non-pathogenic bacteria. In many pathogen detection applications, these non-pathogenic bacteria may “out-compete” the pathogenic bacteria during the detection enrichment steps (click to view the PDF of our Quick Guide.) This competition causes slower growth of the pathogenic bacteria and a probable resultant false negative in detection, regardless of the method - whether DNA or antibody based.
SDIX adds highly-selective phage to its enrichment media to attack the competitors, enabling the food pathogens to rapidly reach detectable numbers.
Simultaneously, any non-pathogenic bacteria present in the sample that are cross-reactive with the detection method (i.e. false positives) can be killed early with the use of appropriate phage. Thus, the use of SDIX bacteriophage technology markedly improves both sensitivity and specificity and, ultimately, the accuracy and results of microbiological testing.
SDIX also has related patent-pending technology for the use of bacteriophage in large-scale industrial bio-fermentations (e.g. ethanol and lysine production) as a bio-control agent.
In such large-scale operations, it is impossible to ensure sterility and these methods can be easily prone to bacterial contamination. The use of bacteriophage enables the rapid, targeted destruction of the contaminant organisms, while allowing the desired production organism to grow unaffected. It also opens a wide range of new operating parameters previously unattainable due to compromises geared toward contaminant control.
In ethanol production, yeast is used to convert sugars from corn into ethanol. Naturally occurring bacteria in the feedstock thrive under these conditions and can negatively impact the production of ethanol, both competing for sugars as well as producing metabolic products detrimental to the yeast. Traditionally, bacteria control is usually achieved by the use of antibiotics. Use of bacteriophage may result in more efficient fermentation yields, as well as eliminating antibiotic residues in the fermentation byproduct, dried distillers grain (DDG), used as animal feed. Here the use of the SDIX bacteriophage technology can improve production yields as well as enhance the value of the production byproducts.