In the book Probiotics, Protection Against Infection, Casey Adamas writes:
“To protect against pathogens, [probiotics] will produce a number of natural antibiotics designed to reduce the populations of [pathogenic bacteria]…”
Moreover, these antibiotic substances are perfectly tuned to kill the invading pathogens. And if the pathogens become resistant to that chemical, then the probiotics will change strategies and produce a new, more effective antibiotic chemical.
Contrast this dynamic probiotic strategy to our static, oral antibiotics which must be phased out every few years (as pathogens evolve resistance). While we may be able to continue to discover new antibiotic substances, nature will always win in the long term. The bacteria will always evolve resistance. This is illustrated by the fact that bacteria can even survive in nuclear waste!
Currently, under labaoratory tests, Bio-15 Probiotics have shown to be able to "kill" viruses & anti-biotic resistant bacteria such as HFMD, E-coli 157, MRSA etc.