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Meningitis

Can anyone help me here?
"what is a typical concentration of bacteria expected if bacterial
meningitis is expected, in C.F.U. / ml"

Andy

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posted by admin in Uncategorized and have Comments (5)

5 Responses to “Meningitis”

  1. admin says:

    Andy:

    This isn’t really an answer to your question, as I don’t know what the
    average cfu/ml are in meningitis. However, CSF is a normally sterile body
    fluid, so ANY growth is considered pathologic. Occasionally samples will
    be contaminated with skin organisms, but the determination of whether it
    is significant or not is made upon the nature of the isolate, rather than
    the cfu/ml. One cfu/ml of Streptococcus pneumoniae is considered
    significant. 100cfu/ml of Staphylcoccus epidermidis is usually considered
    insignificant, unless the patient has some reason to have S. epidermidis
    in their CSF.

    Glen Tamura

    - Hide quoted text — Show quoted text -

    On Mon, 13 Jul 1998, Andy wrote:
    > Can anyone help me here?
    > "what is a typical concentration of bacteria expected if bacterial
    > meningitis is expected, in C.F.U. / ml"

    > Andy

  2. admin says:

    Glen (and others)
    Thanks for your reply!
    I should have made my question more specific.
    I am well aware that any bacteria in CSF is significant (barring
    contaminants).
    However, what I need to know is that when a patient has a bacterial
    meningitis, what level of bacteria would one expect to find!
    It appears that this question has not been answered in many text books as any
    quantity is considered significant!
    Does anyone know the answer?
    I remember looking at CSF and sometimes one could see on a wet prep bacteria!
    So the number can be significant! However, that may just be some cases.
    Are there bacterial meningitis cases where bacteria would be virtually
    undetectable by microscopy?

    Andy

    - Hide quoted text — Show quoted text -

    Glen Tamura wrote:
    > Andy:

    > This isn’t really an answer to your question, as I don’t know what the
    > average cfu/ml are in meningitis. However, CSF is a normally sterile body
    > fluid, so ANY growth is considered pathologic. Occasionally samples will
    > be contaminated with skin organisms, but the determination of whether it
    > is significant or not is made upon the nature of the isolate, rather than
    > the cfu/ml. One cfu/ml of Streptococcus pneumoniae is considered
    > significant. 100cfu/ml of Staphylcoccus epidermidis is usually considered
    > insignificant, unless the patient has some reason to have S. epidermidis
    > in their CSF.

    > Glen Tamura

    > On Mon, 13 Jul 1998, Andy wrote:

    > > Can anyone help me here?
    > > "what is a typical concentration of bacteria expected if bacterial
    > > meningitis is expected, in C.F.U. / ml"

    > > Andy

  3. admin says:

    Andy:

    It is definitely possible for CSF to have a negative gram stain and be
    culture positive. In such cases, I think the cfu/ml are probably quite
    low (>1000cfu/ml). The vast majority of culture positive cases have a
    positive gram stain, in which case I would expect the count to be quite
    high (>10Kcfu/ml). This is, alas, based upon no real data, just the
    personal experience of the lab techs at our hospital.

    Glen Tamura

    - Hide quoted text — Show quoted text -

    On Tue, 14 Jul 1998, Andy wrote:
    > Glen (and others)
    > Thanks for your reply!
    > I should have made my question more specific.
    > I am well aware that any bacteria in CSF is significant (barring
    > contaminants).
    > However, what I need to know is that when a patient has a bacterial
    > meningitis, what level of bacteria would one expect to find!
    > It appears that this question has not been answered in many text books as any
    > quantity is considered significant!
    > Does anyone know the answer?
    > I remember looking at CSF and sometimes one could see on a wet prep bacteria!
    > So the number can be significant! However, that may just be some cases.
    > Are there bacterial meningitis cases where bacteria would be virtually
    > undetectable by microscopy?

    > Andy

  4. admin says:

    Andy wrote:
    > However, what I need to know is that when a patient has a bacterial
    > meningitis, what level of bacteria would one expect to find!

    It often depends on the organism causing the infection.  Most folk who
    have lots of laboratory experience will be able to share stories of
    pneumococcal meningitis where the counting chamber has been replete with
    pneumococci despite having few polymorphs, in other circumstances, the
    reverse can be true.

    > I remember looking at CSF and sometimes one could see on a wet prep bacteria!
    > So the number can be significant! However, that may just be some cases.
    > Are there bacterial meningitis cases where bacteria would be virtually
    > undetectable by microscopy?

    A lot depends on the microscopy and the person performing the Gram’s
    stain etc.

    First of all, methanol fixation is often said to be better than flmaing
    because of potential disruption of cells.  Then I would always prefer a
    cytospin over a standard layered Gram’s stain.  In addition, if Acridine
    Orange is used the sensitivity of microscopy is enhanced.

    We have done away with Bacterial Antigen Detection (BAD) testing because
    we have found a Gram’s stain has been a better predictor, but then we do
    cytocentrifuge.

    There are a reasonable number of times when we see nothing in the Gram’s
    stain but culture a bacterium consistent with ABM.  I suspect other
    laboratory folk have similar experiences.

    Regards

    Gary


    **************************************************
    Dr Gary Lum
    Director of Microbiology and Pathology
    Royal Darwin Hospital

    Microbiologists do it with culture and sensitivity
    http://www.ozemail.com.au/~glum/
    http://www.ozemail.com.au/~glum/Gary%20Lum%20Frames.html
    http://www.ozemail.com.au/~agar
    http://www.ozemail.com.au/~glum/ASMPage.html
    mailto:g…@ozemail.com.au
    **************************************************

  5. admin says:

    This is an interesting question.  It would be helpful if you could elaborate
    on why you are considering a cutoff range in terms of c.f.u. as a basis to
    establish a case of bacterial meningitis.  However, as the meningitis are a
    sterile site, the isolation and or presence of bacteria alone is good
    evidence to suggest meningitis of bacterial origin.

    Eddy M.

    - Hide quoted text — Show quoted text -

    Andy wrote in message <35A9C8CA.5AD5E…@mindless.com>…
    >Can anyone help me here?
    >"what is a typical concentration of bacteria expected if bacterial
    >meningitis is expected, in C.F.U. / ml"

    >Andy