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RE: Fish TB Mycobacterium marinum
Hi Sue,
I use strait bleach on many things which are not porous. For porous
materials I prefer to boil them in salt water. It prevents bleach from
leaching out after the tank is set up. Even so one can not be sure that the
salt water gets into every nook and cranny. How long should I be boiling the
materials for to be completely sure that EVERYTHING is dead. Or are there
pathogens which can survive boiling without an autoclave.
Best regards,
~RJ~
-----Original Message-----
From: owner-killietalk at AKA_Org [mailto:owner-killietalk at AKA_Org]On
Behalf Of Katz, Sue
Sent: Tuesday, November 20, 2001 10:52 AM
To: 'KillieTalk at AKA_Org'
Subject: RE: Fish TB Mycobacterium marinum
> Hi everyone,
> I keep getting the killietalk while I am at home and cannot post from
> there. But being a microbiologist, I can add a few things here:
>
> From: "David Lains" <david at zfin_org>
> David was correct - for disinfection for most bacterial contamination use
> 70% alcohol, rather than more concentrated - this goes for ethanol or
> isopropanol. 100% alcohol dehydrates the bacteria and toughens their cell
> wall, not killing them.
> This does not work for bacterial which produce spores nor for fungi. It
> probably will kill mammalian cells by dissolving their cell membrane.
>
> >From: "Allen N Sandra" <a.boatman at verizon_net>
> >You'll notice I said if it is a mycobater or mycobacterium>
> Uh... I don't quite follow this comment - there are two bacteria which
> have 'myco' in their names:
> mycoplasma - a cell wall less very fragile type of bacteria (can cause
> human pneumonias)
> mycobacteria/mycobacterium - the microbes which cause fish tb, people tb,
> MAC, and leprosy.
> Mycobacteria have a unique cell wall, which contains what we call mycolic
> acids. Their cell wall means that they are very impermeable to
> antibiotics, and also to intake of nutrition. They are very resistant to
> killing by antimicrobial agents and disinfectants.
>
> I'll quote a little from my lecture notes to the med students - I am being
> lazy in not rewriting it - and I know it uses some technical terms. But I
> wanted to give as accurate information as I can.:
> The name Mycobacteria means fungus-bacterium. This refers to the
> fungus-like growth of the organisms on the surface of liquid cultures.
> Like ducks on a pond, they are found growing at the interface of water and
> air in the liquid cultures. The cells and colonies are hydrophobic
> because of the waxes and lipids. They grow at the interface because
> Mycobacteria are obligate aerobes (require oxygen).
>
> Very resistant to drying and most disinfectants due to waxes in cell wall.
> Waxes are a type of lipid.
> BUT: Formaldehyde and Glutaraldehyde are effective disinfectants - For
> many commercial disinfectants, check the label and information or ask the
> manufacturer, if it doesn't say it will kill it, it probably won't.
> The mycobacterial outer cell layer of Lipid contributes to many
> mycobacterial characteristics:
> Exclusion of dyes, not permitting cell to stain Gram
> Positive (one of the most useful staining techniques to
> look at bacteria in the microscope)
> Slow importation of foodstuffs into the cell, causing a slow
> growth rate
> Low permeability to antibiotics and other materials
> Resistance to killing by acidic and alkaline compounds
> Resistance to osmotic lysis via complement deposition (one
> of our immune defense mechanisms)
> Ability to survive oxidative killing mechanisms of
> macrophages (some of our white blood cells)
> Ability to grow intracellularly in macrophages
>
>
> >Also from: "Allen N Sandra" <a.boatman at verizon_net>
> >bleach doesn't do the trick for disinfecting a tank after being hit by
> this particular organism>
>
> I believe that chlorox will in fact destroy the mycobacteria. I would
> follow Jay's pathway and use concentrated chlorox for an extended period
> of time for all things touching that tank.
>
> Wrights comments were very good, and I would certainly like to get any
> references he has found. I have become more and more interested in
> learning more about the extent of M. marinum contamination and
> transmission in our hobby and am putting together assay techniques with
> the intention of putting forward a grant proposal to survey for this
> microbe. Wrights observations will be extremely helpful. My area of
> expertise is with the more common enteric bacteria (like E. coli), so this
> is a new region for me to travel in.
>
> Wright: > Many vets are confused by this genus, as it is murderously
> difficult to culture and study in vitro. It is terribly FRAGILE! Alcohol,
> temperature, drying *or* bleach all kill it with great ease. You can't
> just smear it on an agar plate and get it to grow. It doesn't work that
> way. It isn't even contagious, usually, except through direct wet contact
> with an open wound at tropical tank temperatures. In that sense, it is
> very similar to human pneumonic TB.>
>
> Yup. It is listed as a very slow grower and a real pain. I will be
> attempting to use OTHER methods to find it other than culturing it.
>
> Hope I've helped clear up a little of the conflicting information here.
> Sue Katz
> Microbiology, Arizona College of Osteopathic Medicine, MIdwestern
> University
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