Re: hospital strains of C diff

[Guest guest]

That's a plausible argument. It would seem to me that the hospital

scenario doesn't just remove the selective pressure to keep C diff

benign, but would provide selective pressure for virulence. As you

point out, lots of people are asymptomatic carriers implying that

those strains of C diff can take their sweet time to spread to new

hosts. But the hospital stay is short. In that case, it might

favor the selection of strains that pump out the toxins en masse and

provoke diarrhea (which would presumably be more difficult to

contain and facilitate the rapid spread of spores).

Matt

>

>

> One tidbit that appears in Ewald's book " Evolution of

> Infectious Disease " is that C. difficile is present in the guts

> of about 1 out of every 50 people, without causing problems.

> Ewald theorizes, because of this, that the strains that cause

> people problems may be strains bred in hospitals (where diseases

> have no incentive to evolve toward benignness, because attendants

> can spread them even if they incapacitate the patient). So it

> may have been as much a matter of which bug you picked up in the

> hospital, as of which antibiotics set you up for it.

>