I dont think that would be necessary, Steam is what is really transferring the heat more efficiently to the equipment that is being sterilized. adding a metal basket can potentially reduce efficiency (depending on the material). If your pressure cooker is at 15 psi and at 121 C it will kill pretty much all bacteria...
Using a pressure cooker as an autoclave. - PubMed - NCBI
https://c.ymcdn.com/sites/adint.site...okers_for_.pdf
Just some links that I found
Best regards
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