poets at ccmail.orst.edu
Tue Aug 1 15:59:26 EST 1995
evans at ahabs.wisc.edu (PSE) wrote:
> Laurie Garrett reminds me that microorganisms can and do develop
> resistance to strong chemicals such as chlorine and ammonia based
> Examples are Leigionaires Disease-causing bacteria, V. cholera, E. coli,
> and Cryptosporidium (some Cryptosporidium species reportedly _grow_ in
> the presence of Chlorox).
Are you sure the above bugs are just not in contact with the chemical
for long enough? My understanding is that halogen ions are the best
disinfectants going. Their draw back, especially chlorine compounds,
is that they are easily inactivated by organic contamination. So how
did these experiments show growth in the presence of chlorine? It seems
E. coli and Vibrios will have a lot of organics kicking around with
them especially on growth media.
Don't forget, effective disinfection requires adequate contact time.
Plain old soap is a disinfectant in that it will disrupt cell
membranes if given enough time. The concept of contact time is
why surgeons must scrub for at least 6 minutes to cleanse their hands.
It's virtually impossible to sterilize living skin.
Also, most viruses (I'm not saying all, because some-
body out there works with the exceptions) are inherently resistant
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