There's a problem with size. It's not the penicillin mold that kills bacteria but rather a chemical produced by the mold. Fortunately, that chemical was small enough to be "druggable" as the jargon has it. Any microorganism is going to be thousands of times too large to be druggable, so the idea is a non-starter. Furthermore, living microorganisms excrete, and the excretory products would likely be toxic to humans. Unfortunately, taking a simple analogy and running with it rarely makes for feasible science. It's just a shame that instead of allowing the mass media to terrify us over SARS-COV-2, we sat back and analyzed the actual data. Which would tell us that covid-19 is a non-threat, killing less than 0.2% of the population in even the very worst-hit nations. Compared to lives lost each day from lifestyle-induced diseases (which kill at nearly ten times that rate) we could, if we were wise, ignore covid-19 and thereby avoid having thrown 1.5 billion people out of work, avoid having caused an estimated 15 million to starve to death, and avoid having stopped 140 million children from being vaccinated against diseases that kill 30% - 60% of those infected, versus the 0.2% for covid-19. Even the WHO points out that 14 million to 28 million of the world's poorest and most at-risk children will now die because we were in such a rush to "save" Western lives: these being almost exclusively the very old, the very sick, and the obese.