It's an interesting thought, but perhaps we should consider how susceptible we would actually be. We still build houses from wood, which can rot and be digested

It's an interesting thought, but perhaps we should consider how susceptible we would actually be. We still build houses from wood, which can rot and be digested, but generally doesn't with a reasonable amount of maintenance. Even if an hyper effective microbe were to spread, the manner of spread is unlikely to be any more effective with respect to dispersion than others that e.g. attack wood.