Harro
Adrian Tappin schrieb:
> At 08:39 28/11/99 -0800, you wrote:
> >Even with clean water some Rainbows get skin sores.
> >Because none the aquarium store antibiotics that I have tried work
> >I have experimented with the anti tubercular drug Rifabutin
> >or Mycobutin with success.
>
> Rifabutin is one of a number of drugs suggested for the treatment of humans
> infected with nontuberculous mycobacteria such as "Fishkeepers disease". I
> have not been able to find any successful treatment reports of curing fish
> with a confirmed mycobacterial infection - not yet anyway?
>
> Here's a little bit of information that might be of interest?
>
> Many nontuberculous mycobacteria are resistant to the drugs commonly used
> successfully in the treatment of tuberculosis (e.g., isoniazid,
> pyrazinamide, and streptomycin). Antibiotic regimens may require several
> (five or six) drugs including rifampin, which is quite effective against M.
> kansasii, or clarithromycin, which has marked activity against the M.
> avium-intracellulare complex. Surgical resection is occasionally recommended
> with or without chemotherapy. In treating disseminated infections in AIDS
> patients, a regimen of five or six drugs, including clarithromycin,
> ethambutol and perhaps rifabutin, should be considered.
>
> The mutation rates of mycobacteria are very high, meaning that they quickly
> adapt to their changing environment. Genetic mutation can develop as often
> as once in every million divisions(1,000,000). Each time a genetic mutation
> appears, there is a small chance that the mutation will result in immunity
> to antibiotic drugs that might otherwise have killed the mycobacterium.
> Tubercles (granulomas in the disease tuberculosis) can contain up to one
> hundred billion mycobacteria (100,000,000,000), so the chances of the
> mycobacteria developing resistance to any individual drug is very high.
>
> If a patient with a mycobacterial infection is treated with only one drug,
> the disease may appear to improve temporarily, as most of the bacteria are
> destroyed. However, the disease will usually return, when the bacteria with
> resistance to that one drug have had a chance to multiply. Remember that
> only a very small number of viable mycobacteria are necessary to establish
> infection. Use of that one drug in that same patient is then useless, since
> the infecting bacteria are resistant to it.
>
> For this reason, mycobacterial infections are almost always treated with a
> combination of two or more drugs. The chances of a genetic mutation
> resulting in resistance to two or more drugs at the same time are extremely
> small.
>
> Since mycobacteria are extremely hardy, drug treatment times are extremely
> long. Many species of mycobacteria can become "inactive" for long periods of
> time, i.e. they do not metabolise. Antibiotics can only be effective against
> a bacterium if that bacterium is metabolising. To completely eradicate a
> mycobacterial infection with antibiotics requires that the course be long
> enough to act against bacteria that are "hibernating" as well as active
> bacteria.
>
> To eradicate a pulmonary(lung) tuberculosis infection takes between six and
> nine months of treatment. Tuberculosis outside the lung may take even longer
> to treat. If the antibiotic drugs are not taken until the infection is
> eradicated (e.g.. the patient stops taking the drugs after two months,
> because s/he is feeling better), this gives the bacteria a chance to develop
> resistance to the drugs and it is likely that the patient will relapse with
> the disease. In this case, the drugs used can not be used again, since the
> infecting bacteria will be resistant to them.
>
> Adrian.
>
>
> Adrian R. Tappin
> Brisbane, Australia.
> "Home of the Rainbowfish"
> http://www.ecn.net.au/~atappin/home.htm
>