Asked and Answered:

We asked for your opinion on the recent news on hospital acquired infections from endoscopes. You answered. 

One SPD Manager stated: 
If it cannot be cleaned properly and completely- sterilization WILL NOT MATTER! There is no such thing as sterile dirt. These scopes need to be redesigned, and Olympus needs to respond to this inadequate and dangerous product IMMEDIATELY. We all know know how much they charge for their products and equipment: they need to put their dollars in a new design and replace the ERCPs asap. We are all sitting on ticking time bombs. It’s very alarming we are all using this scope.”
Dr. Warburton Weighs In:
“The SPD manager is not wrong.
The underlying issue is that these scopes cannot be cleaned properly, and therefore if there are pieces of biological residue left behind that can harbor bacteria, infection can occur.
High level disinfectant will kill all viruses, fungi and bacteria, with the exception of bacteria spores, whereas sterilization kills everything including spores.
From my perspective, the issue is not a question of killing spores or not (sterilization vs. disinfection), but how well the HDL/sterilization chemical can penetrate the biological residue left behind and kill the bacteria in it. For example, hydrogen peroxide is a sterilant, but I would not trust it to penetrate very far through a piece of biological residue. Similarly, PAA, OPA, and glutaraldehyde are not designed to penetrate. 
If the sterilant/HLD cannot penetrate the residue, then it does not matter if the chemical is a sterilant or HLD, the bacteria live and infection can still be passed from patient to patient. This is what the SPD manager meant when they said  “sterilization WILL NOT MATTER! There is no such thing as sterile dirt.”
I think the better question therefore is what is the most effective chemical at penetrating miscellaneous biological residue and killing bacteria. The most effective penetrating sterilant/HLD is ethylene oxide. It can even penetrate plastics, which is why it takes so long to aerate. EtO may not completely sterilize the dirt, (i.e. it is not validated to penetrate X mm of miscellaneous dirt – the SPD manager is correct) but it is the best option out there. If one looks at it from a risk perspective, i.e. the risk of transmitting a viable bacterium by a reprocessed scope, the probability of a scope treated with EtO is lower than other methods.
The reason EtO is such a good penetrant is that it is a gas, not a liquid like PAA, glut or OPA, so it is more mobile; and it is does not rapidly react or decompose on contact with biological materials like hydrogen peroxide (think hydrogen peroxide solution fizzing on cuts), which makes H2O2 more of a surface sterilant. EtO can thus penetrate more deeply into the dirt.
The other comments the SPD manager made about the need for Olympus to fix their equipment make good sense.”