PP & GCC,

 Nice comments chaps! A few thoughts:

PP, Doomed it is? Well, in some senses yes, but our global demise demands more than our being unable to kill every germ. As long as we can keep our pitifully dwindling global population to more than a few tens of millions, suitably genetically assorted and outbred, it would take a formidable combination of pathogens to wipe us out.

Mind you, we have no written guarantee of indefinite survival. Probably millions of species (including germs)  have been exterminated in interspecific strife, probably most of them in unequal combat with microbes. Why should humanity be different?

Meanwhile, from the optimistic point of view, there are two factors to begin with: selective breeding and competition. Selective breeding means that, much as happened most dramatically with rabbits in Australia, we get selected to survive the worst of our pathogens, and they get selected not to kill us off too quickly for their own good. Now, before you pedantically, but correctly, point out all sorts of complications to those relationships, I hasten to add that it is a large subject with many complications (and a very interesting subject at that!) but that as a rule this sort of thing does happen remarkably effectively with a remarkable range of diseases in a remarkable range of circumstances. The Black Death (which, together with some epidemiologists, I suspect was a viral disease, and not Yersinia at all) went away within a few centuries after possibly a few million deaths. Syphilis, which was a horror almost beyond description when it struck Europe in the wake of the rape of the Americas, was merely a disgrace and a threat on a par with say, measles, in the late 19th century.  TB to this day is less virulent in ethnic groups that were heavily exposed in past centuries, and complementarily, yellow fever has long been drastically more deadly among colonialistic peoples than equatorial indigenes, a fact that has had enormous historical consequences. These are just a few examples.

Make no mistake, the abuses that you describe are genuine, and some of them, when I am elected global president, I shall take steps to wipe out, probably starting by putting triclosan and a few associated compounds on the prohibited list, along with heroin.   

GCC, good question of course, but not as easy to answer as to ask (not that questioning skills are to be sniffed at in science, to be sure!) As a rule of thumb the strains chosen for testing are pretty helpful; the microbiologists concerned were not being particularly stupid. If those strains are controlled by a particular treatment, then you can reasonably assume that most others would be as well. This said, there are very important reservations. For one thing, each of the four species that Peter mentioned occur in many strains, ranging from practically harmless (even useful as probiotics or normal flora) to dangerously infectious or nosocomial, with horrific degrees of multiple microbicidal resistance. However, none of them is spore forming. I wonder how some of our marvellous commercial products would perform in challenging, say a partly sporulated population of certain Clostridum strains. (Peter? Any ideas?)

Then again, every time anyone begins to explore the environment for evidence of how many unknown bacteria there are in a given environment, they generally retrieve mind-numbing counts. We don’t know what those bugs are, or even whether they are good, bad or indifferent.

Sometimes it really is no easier to answer the questions than to ask.

Cheers,

Jon