[DIYbio] Re: Were the DIY CRISPR kits contaminated?

On Monday, December 11, 2017 at 8:55:16 AM UTC-8, ukitel wrote:

The LGL stated that the bacterial strain supplied in the kit was contaminated with potentially pathogenic species, such as Enterobacter species and Klebsiella pneumoniae.


Actually, it's worse than merely some contamination: they were not able to grow a single E. coli colony!


The Odin produced blast mapping of the E.coli 16S sequence to their bacterial stock and showing 99% identity.


Which is a test that is entirely useless to show the level of bacterial contamination in a sample - that only shows the identity of the dominant species.

I think it's pretty clear there was something seriously wrong with the sample LGL tested. And I don't doubt that you'd get a similar outcome if you tested the same sample again. One possibility is that the sample got overheated in transport or storage, and was mostly dead except for a few more robust contaminant bacteria. I don't think LGL ever reported what the CFU/g count of the culture was, for that matter.

I don't think it's a big deal that there was a problem with a single sample - even the biggest commercial suppliers have a snafu every once in a while. Plus there's a good chance the problem actually occurred after the kit left The Odin.

I do think it would be in The Odin's best interest to have better QC and tracking for the cultures they send out. If they had been able to respond to the LGL report by saying "Oh, that kit was from batch 17, and here is the Certificate of Analysis showing that that batch contained <0.01% contaminant cells"... I think that would have been a much better comeback.

Having an independent facility test for bacterial contamination will add a bit to the price of the kits, but that can be spread out over larger batch sizes if necessary. Here's some very affordable testing services I came across recently for testing contamination in yeast or fermented beverages (just for illustration purposes - you'd obviously need something different to test a bacterial culture):

http://wildpitchyeast.com/lab-services/bacterial-contamination-analysis - $50/sample
https://www.whitelabs.com/other-products/ls6610-complete-microbiological-analysis - $148/sample

Patrik

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Re: [DIYbio] Re: Open Hackerspace for Biotechnologies in Berlin, Germany



On Dec 11, 2017 10:28 PM, "ukitel" <marco.r.cosenza@gmail.com> wrote:
Proszę!

?

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