Proteus Mirabilis, a bacteria.
Proteus are gram-negative rods
which are none lactose fermenting
and have a strong urease activity.
They also have a swarming growth on agar,
which is one of their unique features.
The proteus typically colonize the GI-tract.
Where they live quite happily and normally don't cause any
until or if they're transmitted to the urinary collecting
the urinary tract via spread of fecal flora.
Now, this can occure accidentally
and in fact most commonly is an accidental transmission.
Sometimes however there can be introduction via introduced
such as retained toilet paper which can also cause an
How does this organism cause its disease?
Well, it basically creates an alkaline urine
and it does so through its very strong urease activity.
-ace, an enzyme which cleaves urea into ammonia and carbon
That combination of by-products increases the pH of the
allowing the organism to survive.
However, it unfortunately also increases the collection of
because many of the stone materials will silt out,
or become solid at that particular pH.
And a higher increased urine pH is quite toxic to the
So, proteus mirabilis which has a protease is a common cause
of urinary tract infections
and along with those associated staghorn calculus formation.
Also, because of the urease which it contains and it creates
you can often tell that a patient has a urinary tract
infection with proteus
because the urine smells strongly of ammonnia.
This image shows two side to side comparisons of
of a patient with a staghorn calculus.
If one looks at the initial image on the left of side of the
one can see on the right side of the patient or the right
side of the image
which is the left side of the patient, a large white
which looks sort of a globoid.
That would be your staghorn calculus.
The image on the right now shows further escalation of the
from the cystourethrogram outlining the kidney on the
or the image's left and showing significant dilation
of the intranefric or the intra-kidney structures.
This typically would come from obstructive hydronephrosis
created by calculi further on down.
So, this patient is an unfortunate, very clear example of
formation of a staghorn calculus.
Well, as a stag with a rack of antlers you can see multiple
projecting into the renal parenchyma
which are all calcified or solidified formations of that
Looking just like a rack of antlers.
On this slide, the image on the left is
another example of an intravenous mg ivp
showing a staghorn calculus prior to
The stones are composed primarily of strew,
white and carbonic appetite and
usually contain many bacterial colonies.
The image on the right shows the specimen
removed from the patient in surgery.
And here you can you can appreciate both the
size 123 grams and the
Treatment for this organism.
Most often the organisms are ampicillin susceptible or
but so too one can use Trimethoprim/Sulfamethoxazole,
sulfonamide, or cephalosporins.
So, what to do about this particular organism?
Well, I'm sorry to say if you find it smelling like ammonia
and creating calculi
then you've got your diagnosis even before waiting for the
beautiful culture of a swarming bacteria.