Re: Barb, anyone - what is infective dose of Bb

[Guest guest]

The metrics for counting bacteria are usually called " colony forming

units " or CFUs for short. Counting Gram positive bacteria is

represented by a Log scale because they replicate so fast. AFter

they're cultured, viability counts are listed as: - Log10 CFU/mL - and

are then are plotted over time to show the population increase (or

decrease if it's ab abx suseptibility experiment).

I've seen bacterial counts for Endocardidtis be:

10 to the 9th/G of tissue.

It's possible you misread the viability counts in tissue for borrelia.

It' was probably more like: 10 to the 5th CUFs/mL or per G of

tissue.

There would never be just 10 organisms of anything infectous the body-

it's more like 10 gazilion trillion organisms

Barb

>

> ...known for any mammal?

>

> I thought I had seen it claimed to be 1-10 organisms on some

> website/forum, but I cant find anything.

>

> For Treponema pallidum it is evidently >10 organisms in the

> highly-suceptible guinea pig, with 0/10 pigs infected at 10^1 and 5/10

> infected at 10^2:

>

> http://www.pubmedcentral.nih.gov/picrender.fcgi?

artid=257764 & blobtype=pdf

[Guest guest]

Oh, I'm talking injected infectious doses, not infection tissue

concentrations.

Of course the chances of getting infected by one microbe or five are

nonzero but they are usually low, because the handful of microbes will

probably all be destroyed by the host. So, you see figures like ID50

for the infectious dose (number of organism Y) that infects

individuals of host X 50% of the time.

Of course it can be different for other infection routes, eg for

humans there is a low infective dose for M tuberculosis bacilli

contained in 1-3 um aerosol droplets produced by coughing.

<egroups1bp@y...> wrote:

>

> The metrics for counting bacteria are usually called " colony forming

> units " or CFUs for short. Counting Gram positive bacteria is

> represented by a Log scale because they replicate so fast. AFter

> they're cultured, viability counts are listed as: - Log10 CFU/mL - and

> are then are plotted over time to show the population increase (or

> decrease if it's ab abx suseptibility experiment).

>

> I've seen bacterial counts for Endocardidtis be:

> 10 to the 9th/G of tissue.

>

> It's possible you misread the viability counts in tissue for borrelia.

> It' was probably more like: 10 to the 5th CUFs/mL or per G of

> tissue.

>

> There would never be just 10 organisms of anything infectous the body-

> it's more like 10 gazilion trillion organisms

>

> Barb

>

>

>

>

>

>

>

> >

> > ...known for any mammal?

> >

> > I thought I had seen it claimed to be 1-10 organisms on some

> > website/forum, but I cant find anything.

> >

> > For Treponema pallidum it is evidently >10 organisms in the

> > highly-suceptible guinea pig, with 0/10 pigs infected at 10^1 and 5/10

> > infected at 10^2:

> >

> > http://www.pubmedcentral.nih.gov/picrender.fcgi?

> artid=257764 & blobtype=pdf

[Guest guest]

Oh sorry-

Gee.. I don't know how many organisms can migrate

out of the ticks gut - probably depends on how long it feeds

when things get mobilized..

Barb

> > >

> > > ...known for any mammal?

> > >

> > > I thought I had seen it claimed to be 1-10 organisms on some

> > > website/forum, but I cant find anything.

> > >

> > > For Treponema pallidum it is evidently >10 organisms in the

> > > highly-suceptible guinea pig, with 0/10 pigs infected at 10^1

and 5/10

> > > infected at 10^2:

> > >

> > > http://www.pubmedcentral.nih.gov/picrender.fcgi?

> > artid=257764 & blobtype=pdf

[Guest guest]

Yeah, it does look like theres a time-relationship overall. Special

factors may apply, too, in tick bite, such as anti-immune factors

injected by ticks, which inadvertantly benefit any invading organisms.

>

>

> Oh sorry-

> Gee.. I don't know how many organisms can migrate

> out of the ticks gut - probably depends on how long it feeds

> when things get mobilized..

> Barb

>