Microbio Techniques

JEDilworth bactitech at nospamhortonsbay.com
Wed May 29 09:50:44 EST 2002

Why? What difference will the sensitivities make?

You definitely need anaerobic conditions. Proprionibacteria only come up
after 2-3 days incubation. They are tedious to identifify. We use a
Rapid ANA methodology and half the time the ID's don't work very well
and we end up ID'ing from gram stain morphology. Performing antibiotic
sensitivity testing on these slow growers will be expensive and tedious. 

Do you happen to have access to a lot of cash? You will need anaerobic
primary isolation agar of some sort, anaerobic baggies (BBL makes them -
I'm sure they're expensive), an incubator capable of reaching 35 degrees
C, inoculation loops, lots of slides and gram stain reagents, some sort
of antibiotic for sensi testing (our Ph.D. uses predispensed microtiter
plates [expensive] when running antibiotic sensis - I don't perform them
so I don't know what's all involved. As John said, there are also E-Test
strips, but they are not cheap either and must be stored in a freezer
until used, as they are fussy). Our aerobic microtiter setup includes
the plates, the inoculation media, a calibrated 100 ul pipette.

I don't understand, I guess, why you would worry about this. P. acnes
isn't really considered a pathogen, unless it gets into a shunt or
invasive catheter tip inserted when a patient is in the ICU. P. acnes is
normal skin flora. I've found that most normal skin flora is fairly
resistant to antibiotics as it's exposed to the rigors of the
environment on a daily basis.

You may want to investigate clinical laboratory resources if you really
want to pursue this. In a clinical lab, as I've said, we don't get too
excited about this organism as it usually shows up as a skin contaminant
and rarely as a pathogen.

Judy Dilworth, M.T. (ASCP)

Lorren wrote:
> I wish to culture P. acnes. You see, I've been cycled through several
> antibiotics over the years and I would like to culture the strains specific
> to my skin and determine resistance characteristics. I have access to a
> community college lab, though I don't belive they have an anerobic
> incubation chamber. Perhaps something could be inprovised... and anaroebic
> culture bag or so forth. The college doesen't have the literature resources
> that are essential for this project, which is why I am inquiring here.

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