Product Description & Summary
Cycloserine Cefoxitin Fructose Agar with Horse Blood and Taurocholate (CCFA-HT) is an enriched selective media used for the isolation and presumptive identification of Clostridium difficile, a recognized cause of pseudomembraneous (antimicrobial agent-associated) colitis.
CCFA-HT is an enriched selective media used for the isolation of Clostridium difficile. The basic nutritive base consists of animal peptones and fructose and is supplemented with cefoxitin and cycloserine at concentrations that inhibit the growth of most normal fecal flora. Cycloserine will inhibit gram-negative bacteria, while cefoxitin will inhibit both gram-positive and gram-negative organisms. Clostridium difficile is not inhibited on the CCFA-HT media and when grown, will exhibit a characteristic colonial morphology, fluorescence, and smell. Horse blood is added to stimulate growth. Sodium Taurocholate is added to help in the germination of spores. This media is prepared, dispensed, and packaged under oxygen-free conditions to prevent the formation of oxidized products prior to use.
Interpretation of Results & Limitations
If used properly, CCFA-HT supports good growth of species of C. difficile. After 24 – 48 hours, most colonies of C. difficile are large, grey, slightly filamentous, and low umbonate to flat. These colonies fluoresce golden yellow/chartreuse under long-wavelength UV light.
CCFA-HT will not provide complete information for identification of bacterial isolates. Rare strains of C. difficile may be inhibited. Plates must be examined no later than after 48 hours of incubation for optimal selectivity, because after 3 – 5 days of incubation, significant numbers of colonies other than C. difficile may grow. At 48 hours, colonies of most other organisms (e.g. Lactobacilli, Clostridia, and yeast), which may grow, are very small (pinpoint to 0.5 mm in diameter) and do not fluoresce golden-yellow. A test for aerotolerance should be used to confirm that each colony type is an obligate anaerobe. Consult reference materials for additional information.
Quality Control
The following organisms are routinely used for quality control performance testing at Anaerobe Systems.
Organism Tested |
ATCC # |
Results |
Time |
Special Reaction |
Bacteroides fragilis |
25285 |
No Growth |
|
|
Enterococcus faecalis |
29212 |
No Growth |
|
|
Clostridium sporogenes |
3584 |
No Growth |
|
|
Clostridium beijerinckii |
8260 |
No Growth |
|
|
Proteus mirabilis |
12453 |
No Growth |
|
|
Clostridium perfringens |
13124 |
No Growth |
|
|
Clostridium sordellii |
9714 |
No Growth |
|
|
Clostridium innocuum |
14501 |
Inhibited to No Growth |
|
|
Clostridium difficile |
9689 |
Growth |
24 hrs |
Chartreuse fluorescence |
Clostridium difficile |
700057 |
Growth |
24 hrs |
Chartreuse fluorescence |
Product Storage & Shelf Life
Storage: Upon receipt, store at 2 – 8oC in original packaging until used. Avoid overheating or freezing. Do not use media if there are signs of deterioration (shrinking, cracking, or discoloration due to oxidation of media) or contamination. The expiration date applies to the product in its original packaging and stored as directed. Do not use product past the expiration date shown on the container.
Shelf Life: 90 days from date of manufacture.