dog and cat assay data sheet
Clostridium difficile
Test code:
B0037
- Qualitative detection of Clostridium difficile
bacteria
by polymerase chain reaction.
This
assay differentiates pathogenic and non-pathogenic strains of C. difficile by detecting
the toxin producing genes.
C.
difficile is among the Clostridium species
detected in B0061
Clostridium species screen
B0037 is included on
P0022
- Canine diarrhea panel
Clostridium difficile is a gram
positive, anaerobic, spore forming motile rod bacterium that
commonly inhabits the intestinal tract of many mammalian
species, reptiles and birds. It is also found in the
environment. The bacterium is a highly diverse organism, with
more than 400 unique types, and has several virulence factors.
Exotoxin A and B are the most significant factors, and
bacterial production of exotoxins is correlated with
pathogenicity of individual strains of
C. difficile. Toxin A is an enterotoxin, promoting
fluid exudation from the intestinal mucosa, and acts
synergistically with the cytotoxic toxin B through attachment
to specific receptors on the surface of enterocytes. The
combined action of these toxins results in necrosis of
superficial epithelium and edema in affected areas of
intestine.
The organism is an important cause of
enteric disease in laboratory rodents and horses. Hamsters,
guinea pigs and mice may be affected by pseudomembranous
colitis induced by antimicrobial therapy. In neonatal foals,
C. difficile has been associated with hemorrhagic
necrotizing enterocolitis and diarrhea. The lack of an
established intestinal microflora may make foals more
susceptible to colonization by this bacterium. Adult horses
may develop typhlocolitis and outbreaks of nosocomially
acquired diarrhea have been reported (Donaldson and Palmer,
1999; Madewell et al., 1995; Perrin et al., 1993).
C. difficile has also recently been
implicated as a cause of typhlocolitis in nursing piglets,
chronic diarrhea in dogs and enterotoxemia in ostriches.
In clinically normal patients, an
established intestinal microflora is thought to competitively
prevent proliferation of C. difficile and subsequent
toxin attachment. Alteration of intestinal microbial balance
with antibiotic use and increased exposure to the organism in
a hospital setting allows C. difficile to colonize
the gut in susceptible individuals.
Bacterial culture of C. difficile
is not highly sensitive and does not differentiate the
pathogenic and non-pathogenic strains. Specific tests for
C. difficile
toxins used in the diagnostic laboratory include cell
culture, which relies on the presence of biologically active
toxin, and an ELISA assay which detects immunologically active
toxin that may or may not be biologically active.
PCR detection of C. difficile is
highly sensitive and can discriminate between toxigenic and
nontoxigenic strains of the organism by detecting its toxin
producing genes.
Utilities:
- Confirm the disease causing agent
- Shorten the time required to confirm a
clinical diagnosis of C. difficile infection.
- Ensure that animal groups or populations
are free of this bacterium
- Early prevention of spread of this
bacterium
- Minimize human exposure to this bacterium
- Safety monitoring of biological products
that derive from animals
References:
Donaldson, M.T. and Palmer, J.E. (1999) Prevalence of
Clostridium perfringens enterotoxin and Clostridium difficile
toxin A in feces of horses with diarrhea and colic. J. Am.
Vet. Med. Assoc. 215:358 361.
Madewell, B.R., Tang, Y.J., Jang, S., Madigan, J.E., Hirsh,
D.C., Gumerlock, P.H. and Silva, J. (1995) Apparent outbreaks
of Clostridium difficile associated diarrhea in horses in a
veterinary medical teaching hospital. J. Vet. Diagn. Invest.
7:343 346.
Perrin, J., Cosmetatos, I., Gallusser, A., Lobsiger, L.,
Straub, R. and Nicolet J. (1993) Clostridium difficile
associated with typhlocolitis in an adult horse. J. Vet. Diagn.
Invest. 5:99 101.
Specimen requirements:
Rectal swab or 1 ml feces, shipped overnight at room
temperature.
For specimen types other than those listed
here, please call to confirm specimen acceptability and
shipping instructions.
For all specimen types, if there will be a
delay in shipping, or during very warm weather, refrigerate
specimens until shipped and ship with a cold pack unless more
stringent shipping requirements are specified. Frozen
specimens should be shipped so as to remain frozen in transit.
See shipping instructions for
more information.
Turnaround time: 2 business
days
Methodology: Qualitative
PCR
Normal range: Nondetected