What is an outcome of using penicillin?

The outcome of using penicillin is primarily the destruction of harmful bacteria. Penicillin is an antibiotic that works by inhibiting the synthesis of bacterial cell walls. This leads to the death of the bacteria, effectively treating bacterial infections. This mechanism allows penicillin to target and eliminate the pathogens causing illness, making it a powerful tool in medicine to combat bacterial diseases.

The other options refer to processes that either do not occur due to penicillin use or are unrelated to its purpose. For instance, enhancing bacterial growth would be contrary to the effects of an antibiotic. Similarly, stimulating viral infections is irrelevant since penicillin is ineffective against viruses, and yeast production improvement is not associated with penicillin's action, which is specific to bacteria. Thus, the correct answer highlights penicillin's role as an antibacterial agent.