Re: Tuberculosis: Advances in Diagnosis and Therapy

February 9, 2006

The thing that confuses me is that Lyme hasn't been observed to become

drug resistant, or that's what they tell us anyway. I mean, it doesn't

seem to need to in order to survive.

- Kate

On Wednesday, February 8, 2006, at 04:31 PM, Nelly Pointis wrote:

> Things to be learnt from TB treatment?

>

> Nelly

>

February 9, 2006

> The thing that confuses me is that Lyme hasn't been observed to

become

> drug resistant, or that's what they tell us anyway. I mean, it

doesn't

> seem to need to in order to survive.

There are two kinds of resistance - genomic resistance (mutation) and

phenotypic resistance. I think our problem is phenotypic resistance,

resistance that comes about without any mutation, but rather because

the physical state of the bacterium is changed.

In pulmonary MAC, you can take the patients organisms, grow them in a

tube, and obliterate them with clinical concentrations of drugs. Yet

if you are a person with MAC and get cured, youre lucky.

Take a look at this free paper, its the key observation:

Why do abx stop Cpns metabolism in epithelial cells, but not in

phagocytes? Because the phagocyte is hostile. Its nasty conditions

are forcing Cpn to change its behavior, change its protein

expression, and this (or perhaps simply reduced metabolic speed)

makes the difference in drug sensitivity.

How exactly does this work? No one knows. At least its being studied

intensively in Mtb, but theres no guaruntee that its the same or

similar in all bacteria.

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