Elimination of contamination without caesarian derivation--success or failure?

Unfortunately, only successes tend to be published, so we are denied knowledge of partial successes and failures regarding SPF unit breakdowns. If more workers were prepared to be open about their partial successes, a combination of various techniques are appropriate to the case, could prove to be most successful. Each SPF colony is different and must be considered on its merits, nature of contamination, species and strains of animals and so on, but it would seem that caesarian derivation is not now always the only course of action.