Question on unknown organism
somewhere at nospamxplease.org
Mon Aug 4 11:22:42 EST 2003
"John Gentile" <yjgent at cox.net> wrote in message
news:20030802131700619-0400 at news.east.cox.net...
> In <fc613796.0308010628.2fef967 at posting.google.com> SARAH ANDERSON wrote:
> > I have to id an unkown organism. I have verified that it is a Gram
> > Positive Bacillus.
> > I did a spore stain and it was negative. However, when I looked at the
> > organism under a scope after the spore stain, it looked like
> > diplococcus.
> > My questions are: could there be a diplobacillus that looks like
> > diplococcus? Any explanation for this?
> > Or do I probably have contamination?
> > My unknowns could possibly be Mycobacterium smegmatis or
> > Corynebacterium species based on the spore results- I will do an acid
> > fast test next week to determine this...but in the meantime, I'm
> > puzzled by the spore test...
> > Any help would be appreciated. Thanks!
> Sarah, most of the people on this newsgroup will not give you direct
> answers for assignments like this. However, one of the great things
> about micro is the thrill of discovery when you finally identify an
> organism that is baffling you.
> I don't know the source of the isolate, but usually school projects
> usually use well defined ATCC strain. The tests you do to those
> organisms USUALLY work fine. But one of the things I've always
> communicated to anyone learning micro is that the bacteria don't read
> the micro books and will generally do anything they damn well please.
> You have to be smarter than they are.
> A couple of questions for you to look up. What kind of organism is Gram
> pos, rod shapped and produces spores? What do they look like? What size
> is a typical cell? What kind of colony do they produce?
> What kind of media are you growing this unknown on? What kind of colony
> type do you have? Does it match one of your suspect organisms?
> Can that media support the growth of your suspect organisms?
> I can tell you that 90% of the time bacterial identification will go
> very smoothly. Sometimes you have to dig a bit more. I had an organisms
> isolated from a stool sample that was Gram neg rod, lactose neg, glucose
> pos, indole pos and H2S pos. One of my techs thought it was a Salmonella,
> but the indole didn't agree. After a couple of days and 30 or so tests I
> came up with E. coli, H2S pos! I sent it to the State lab for
> confirmation and they were equally baffled, but did agree with my id.
> Good luck!
Lactose fermenting salmonella? How about serogrouping tests to confirm that
it was not salmonella?
More information about the Microbio