Most agents that kill bacteria on contact are used topically not internally for obvious reasons. If it can kill bacteria it can also kill healthy cells. A common bactericidal agent is wood alcohol. It is a main ingredient in those clear antibacterial gels that we see everywhere. It not only kills bacteria effectively but it also evaporates away quickly leaving only the gel that was used to carry it on a person's skin.
Most of the things that kill bacteria inside an organism are bacteriostatic in nature. They damage or impede the cell in some way so that it can not grow or reproduce leaving the bacteria an easy target for the immune system.
It is also good to keep in mind that not all bacteria is harmful. We need certain kinds of bacteria in our digestive tract in order to be healthy.
I am not a biologist and it is easy to over simplify these concepts and come to strange conclusions. But just looking at this subject it is easy to see the wide range of spiritual applications. Everything from fostering lust and the spreading of gossip all the way to the persecution of the Church and attack on the Gospel message to make it palatable but not reproductive.
"For lack of wood the fire goes out, and where there is no whisperer, quarreling ceases. As charcoal to hot embers and wood to fire, so is a quarrelsome man for kindling strife." - Proverbs 26:20-21 ESV
"That in blessing I will bless thee, and in multiplying I will multiply thy seed as the stars of the heaven, and as the sand which is upon the sea shore; and thy seed shall possess the gate of his enemies" - Genesis 22:17 KJV
"And he said to his people, 'Behold, the people of Israel are too many and too mighty for us. Come, let us deal shrewdly with them, lest they multiply, and, if war breaks out, they join our enemies and fight against us and escape from the land.' Therefore they set taskmasters over them to afflict them with heavy burdens. They built for Pharaoh store cities, Pithom and Raamses." - Exodus 1:9-11 ESV
"The LORD your God will clear away these nations before you little by little. You may not make an end of them at once, lest the wild beasts grow too numerous for you." - Deuteronomy 7:22 ESV
This study can go in many directions but it has me thinking of the things in my life that foster spiritual growth and the ones that seem to inhibit it. On the other hand what causes carnality to get a foothold in my life?
Does television have bacteriostatic influence on our spirituality? It can under certain circumstances for me. Teaching on the tongue regularly at church can have that same affect on gossip in that Church.
"And do not grieve the Holy Spirit of God, by whom you were sealed for the day of redemption. Let all bitterness and wrath and anger and clamor and slander be put away from you, along with all malice. Be kind to one another, tenderhearted, forgiving one another, as God in Christ forgave you." - Ephesians 4:30-32 ESV
"Pray without ceasing, give thanks in all circumstances; for this is the will of God in Christ Jesus for you. Do not quench the Spirit." - 1 Thessalonians 5:17-19 ESV
Our spiritual life is a right now kind of thing. Communion is present tense. At the same time the decisions we make today affect the potential spiritual climate of tomorrow.
Our minds are like gardens. What is growing there?