Can you pick up a bacterium?

BCapstone bcapstone at
Mon Oct 24 17:50:08 EST 1994

In article <hlr.8.0F45655F at>, hlr at (Haze) writes:

<It's true that you could separate the cells by flow cytometry BUT
always a but) it will depend on how many bacteria of the type you want are

present as a proportion of the total cell load. Flow cytometers are
operated with an analysis rate of 1000-10,000 cells/sec (typically the
number for sorting applications). So if the cell type you are interested
in is 
present at less than 1/10,000 or so you would have problems using this 
<Would it be possible to enrich for the bacteria for example by
lysing the sperm, leaving the bacteria intact (this approach has been used
detect bacteria in blood by flow cytometry where the starting
from memory was around 10^9 blood cells and 10-100 bacteria /ml). 
Alternatively it may be possible to separate the bacteria from the sperm
their density difference. Such preliminary steps would then give you a
chance of separation by flow cytometry. 
<Once you have an appropriate sample it is indeed possible to take a mixed
suspension and drop a single cell of the type you require into (for
example) a 
well of a microtitre plate or to put most (up to 99% recovery has been 
reported) of the cells of your selected type into a collection tube for 
further analysis.>

This and the prior post are the first I have heard of flow cytometry.  I
would like to separate out the bacteria in a semen specimen that has mixed
bacterial flora.  The patient has prostatitis and was recently septic with
Enterobacter Cloacae.  Different media has not grown the E. Cloacae from
the semen.  In fact 38 previous cultures of Expressed Prostatic Secretion,
semen, and urine, were negative for it, usually growing coagulase negative
staph or having no growth.  No other source of sepsis has been determined.
 On microscopy there are sperm, white blood cells, lots of cocci, and
scattered gram negative rods of different shapes. 
If you or anyone knows a lab that might be interested in this particular
clinical situation please let me know.

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