Can Genetic Engineering Render Disease Germs Harmless?

Humans have very good immune systems, and over time, evolution has enabled us to tolerate bacteria that used to kill us. My question: can we genetically modify disease germs so that they become harless to us? And, also make the altered germ more successful, so it can out-compete the bad (disease-causing germs)?
Take something like tetanus-which can kill you now-could it be turned into a version that would be harmless?
How about viruses? Or is virus RNA impossible to alter?

Are you asking about theory, or right now? And are you asking about particular laboratory situations, or something that can be caused to happen within a living person/animal?

So on the one hand, you want them to be harmless, so they can’t infect us and/or are easily killed once they’re in the body, but on the other hand, you want them to outcompete wild germs? Do you not see a contradiction there?

The problem with engineering germs is that there’s some severe selective pressure going on with them that keeps them constantly adapting to every move we make. Thus, anything we introduce that’s favorable to us will almost certainly be outcompeted by what’s already out there, barring some sort of wild sci-fi superbug or nanotechnology that seeks and destroys. So step one in replacing nasty wild bugs with friendly tame bugs is to eradicate the nasty wild bugs. If we could do that, step two becomes somewhat superfluous.

The closest thing I can think of to what you’re asking is the process by which very deadly bugs, like Ebola, mutate to less deadly but more easily transmissible versions. Killing your host too quickly isn’t a great evolutionary strategy. In a way, you could also consider vaccines to work along the principle you’re suggesting - harmless viruses that give us immunity to dangerous ones. But that’s not generally done via genetic engineering, but by serial transmission, using heat-killed viruses, or using immunogenic components.

I think genetically engineered reindeer would wreak havoc on Christmas.

I believe that experiments have been done in this direction. I don’t know how far along they are or recall many details though. I recall reading of one idea; to render an organism ( dysentery I think ) immune to the virus which triggers its disease causing state. Then deliberately infect people with the resistant strain.

ralph124c appears to be talking about making them harmless, not more vulnerable. Which should be possible; we are full of harmless bacteria.

Not really. Eliminating the nasty bugs won’t keep new nasty ones from evolving. What you are missing is that there is only so much space in an ecological niche; if you fill it up with a harmless organism, the nasty one will have serious difficulties taking hold.

And cooperation with the host organism is a perfectly viable Darwinian strategy; its not necessarily so that the virulent organism will outcompete the inoffensive ones. We are, in fact full of the things.

Live attenuated vaccines are examples of pathogens which have been rendered (relatively) harmless, although the mechanism used to genetically engineer them is relatively crude.
The dilemma in your idea is how to rid the natural reservoir of the pathogenic versions.

Most microoganisms (take Escherichia coli as an example) are already pretty benign. There is no value in making another benign variant of E. coli.

Tetanus, of course, is defended against by using a variant of the toxin (a “toxoid”) instead of a derivative of Clostridium tetani itself.

Disease-causing bugs currently have no problem invading us no matter how many harmless bugs are already living in us. The only way you’re going to “fill up” an ecological niche with an engineered organism is to wipe out the original population first, as I touched on in my first pots.

And while there are exceptions out the wazoo, the ability of organisms to cause disease is, generally speaking, a survival benefit. Look at cholera, or the common cold. I did some work in a cholera lab, and strains lacking pathogenicity genes are quickly eliminated from a wild-type population.

That’s not true. One of the benefits of having harmless microroganisms living on and in us is that it helps prevent infection. They scarf up nutrients that otherwise more dangerous ones could use to grow easier, faster.

This being the SD and all, and GQ being the most pedantic of boards here, let me fine-point this a titchy bit, please…

Many of the “harmless bugs” we already have living in us are part of normal flora which is not simply “harmless” but protective, and they do make it harder for pathogens to invade.

A common example might be antibiotic-associated colitis, which can occur when an antibiotic kills off normal gut flora and allows more pathogenic ones to take over and precipitate diarrhea. The normal gut flora are not only harmless, but protective, and make it difficult for the pathogenic (but otherwise feebler) bacteria to take over. Here’s another specific example (and there are many) where some normal flora are felt to be protective:

" A study was undertaken to evaluate the incidence of nasopharyngeal -streptococci with inhibitory activity against pathogens, as a defense mechanism of the normal bacterial flora against infection. Cultures were taken from the nasopharynges of 43 children with otitis media with effusion (OME). The detection rates of -streptococci with inhibitory activity against Haemophilus influenzae, Streptococcus pneumoniae, Staphylococus aureus and group A streptococci were significantly lower in the nasopharynx than those isolated from the tonsils of the same patients. Moreover, the detection rates of -streptococci with inhibitory activity against all of these pathogens derived from the nasopharynx were lower than those in healthy children, streptococcal strains with activity against H. influenzae and Strep. pneumoniae were also lower than that in patients with tonsillitis. These findings suggest that low nasopharyngeal levels of -streptococci with inhibitory activity against respiratory pathogens may render children susceptible to OME. Further studies are needed to investigate the relationships between the prevalence of pathogens in the nasopharynx and the inhibitory activities of -streptococci against them in order to devise and select optimal treatment for patients with OME."

As with any other invader, pathogenic bacteria have to gain a foothold, and one of the barriers they face is the normal “harmless” bugs already staking out their claims to that part of us.

OK, it would have been more accurate to say that many disease-causing bugs are able to infect us despite the normal flora that we carry. I think it’s a leap to go from that to supposing that having more harmless bugs would make it more difficult for them to infect us. That would need to be demonstrated.

Let me try to restate what I’m trying to get at from another direction. I’m not saying that it would be impossible to do what the OP is saying, but if I were in charge of the project, it’s not the method I’d choose. Basically what he’s suggesting is that we genetically engineer versions of disease-causing microbes that will outcompete the wild-type versions that are already out there. This is a huge task, and I would suggest it’s one that’s beyond our current capabilities. The wild-type versions have been honed by evolution and its concomitant millions and millions of years of trial and error. To suppose that we can simply whip up something in the lab that will do better than that is, in my opinion, unrealistic. Not only better, but better by such a margin as to significantly reduce disease rates by taking over the ecological niches occupied by the wild microbes. Wild microbes, which, let us not forget, still have the capability of evolving and adapting to whatever competition we throw at them. Not impossible, perhaps, but certainly not simple. To me, the idea of “crowding them out” seems much much more difficult and less likely to succeed than, say, coming up with new types of antimicrobial drugs or finding ways of enhancing our immune systems or any number of other strategies.

“We want to breed wolves that don’t eat humans or sheep, but are so competitive that they force out the regular wolves who will then starve…”

Not as long as there are sheep and people around.

I suppose diseases could be make harmless (a mild fever, say) and train uor system against the regular disease. They can’t really “force out” the regular bacteria unless they have such a huge presence that they leave no room for more bacteria or virus. That’s really pushing the limits of “harmless” if your cells are swimming in the stuff. One false genetic transcription and “poof” we’re all dying of sheep flu.

Plus the problem is that gene duplication is not as simple as it sounds. Errors in copying happen all the time - that’s where evolution comes from. Various one-cell organisms will trade portions of genes from time to time (probably the first driver of evolution before sex). I seriously doubt any lab wants to create an organism which is designed to aggressively occupy the human body, no matter how harmless. The risk of some new disease emerging is high enough without us encouraging it.

This is why they say a lot of the flu variants tend to come from the South-East Asia area. Peopel keep pigs and domestic birds in close proximity to humans and with sometimes dubious sanitary conditions. Add to this the mix of wild-bird feces dropping in from the sky, after being collected on migratory routes from all over asia, and teh one in a trillion risk of a genetic combination happening that creates a new and virulent disease variant is high. Add to that the proximity of humans to pick up that disease an distribute it in human channels…