Thursday, August 29, 2013

Clostridium botulinum vs Clostridium sporogenes

Over the last couple of weeks, I have been interviewed many times by radio, television and newspaper reporters on the issue of the Fonterra whey protein concentrate scare and the resulting recall of infant feeding formulae.

One question that has always cropped up is "Why did it take so long for the company and Ministry of Primary Industry to tell the public whether the contaminant was Clostridium botulinum or Clostridium sporogenes?"

I have never knowingly worked with C. botulinum.  It's a dangerous organism because it produces a neurotoxin and special precautions are necessary to work with it.  But when working with food samples and isolating anaerobes (microorganisms that grow in the absence of oxygen), there is always the possibility of unwittingly isolating and amplifying something dangerous.

However, some of my associates have worked with these bacteria.  They tell me that the two bacteria are very difficult to distinguish.  Indeed, Dr Heather Hendrickson, lecturer in evolutionary genetics, Massey University, has said that the two bacteria differ by only one gene.  So obviously, growing the bacteria in culture media and conducting biochemical testing will not allow them to be distinguished.  Very specific molecular techniques must be applied to show the difference and I am told that there are difficulties in carrying out this method.  ESR in New Zealand has the ability to conduct these analyses.

Just for interest, I searched for SEM images of the two bacteria and found the following on-line.  Both images are false colour, and show the impossibility of telling them apart by their appearance.  See the difference?


2 comments:

Paul Harrison said...

So it looks like a precautionary product recall was the correct thing to do. I am sure that the numerous reviews will improve the communication procedures. Its bizarre how much the media distorted of lot of the scientific information.

Batlah said...

thanks Prof.John for this article ,,

It's make me more understand,, I'm Just wonder how these two bacteria be almost the same except in one gene and if this gene turned off or replaced in Clostridium botulinum by one of molecular methods in lab, can we generate non-pathogens Clostridium botulinum ?

Batlah

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