CDC is an enriched medium for the growth and partial identification of obligate anaerobes.  It also supports good growth of aerobic, facultative anaerobic and microaerophilic organisms found in clinical materials if incubated under the appropriate conditions.  CDC is a tryptic soy agar base supplemented with vitamin K1 and hemin to facilitate the recovery of more fastidious organisms, such as Prevotella, Porphyromonas, and the Bacteroides fragilis group, and should facilitate pigment production of Prevotella melaninogenica. Sheep blood is added for the observation of hemolytic reactions as seen by the double zone beta – hemoylsis of Clostridium perfringens. This medium is prepared, dispensed and packaged under oxygen-free conditions to prevent the formation of oxidized products prior to use.

               Anaerobe Systems PRAS CDC
           Anaerobic Blood Agar (CDC) AS-646

Formula

Tryptic Soy Agar, 40.0 g

Yeast Extract, 5.0 g

L-Cystine, 0.4 g

Hemin (0.1% Soln), 5.0 ml

Vitamin K₁ (1% Soln), 1.0 ml

Sheep Blood, 50.0 ml

Distilled Water, 1000.0 ml

 

Final pH 7.3 +/- 0.2 at 25 degrees C.

Final weight 16.0 g +/- 1.6.

                                                                                                               

Precautions

For IN VITRO DIAGNOSTIC USE only.  Approved biohazard precautions and aseptic techniques should be observed when using this product.  This product is for use only by properly-trained and qualified personnel.  Sterilize all biohazard waste prior to disposal.

 

Storage and Shelf Life

Storage:  Upon receipt, store at room temperature (13°C - 27°C) in original container until use.  Avoid overheating or freezing.  Do not use medium 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.

 

Procedure

Specimen Collection:  Specimens for anaerobic culture should be protected from air (oxygen) during collection, transport and processing.  Consult appropriate references for detailed instructions concerning collection and transport of anaerobes.

Methods for Use:  CDC should be inoculated directly with clinical material or a broth that has been previously inoculated from clinical material.  Inoculated plates should be streaked to obtain isolated colonies, immediately placed in an anaerobic atmosphere and incubated at 35-37^oC for 18 – 48 hours.  Additional periods of incubation may be necessary to recover some anaerobes.  Detailed instructions for processing anaerobic cultures can be found in the appropriate references.

Materials Required But Not Provided

Standard microbiological supplies and equipment such as loops, saline blanks, slides, staining supplies, microscope, incinerator or autoclave, incubators, anaerobic chamber or anaerobic jars, disinfectant, other culture media and serological and biochemical reagents.

 

Limitations

CDC will not provide complete information for identification of bacterial isolates.  Additional test procedures and media are required for complete identification.  It is recommended that a selective medium such as Anaerobic Brucella Laked Blood Agar with Kanaymcin and Vancomycin (LKV) and/or Anaerobic Brucella Blood Agar with Phenylethyl Alcohol (PEA) also be inoculated from clinical specimens to assure growth of all species present.  Consult reference materials for additional information.

 

Quality Control

This medium should support the growth of obligate anaerobes found in clinical infections.  In addition, the medium should support typical pigment production by pigmented Prevotella and Porphyromonas spp.  It also should support typical double zone of hemolysis around colonies of Clostridium perfringens.

The following organisms are routinely used for quality assurance performance testing at Anaerobe Systems. 

Organism Tested	ATCC #	Results	Time (Hours)	Special Reaction
Bacteroides fragilis **	25285	Growth	24 h
Prevotella melaninogenica **	25845	Growth	24-48 h	Pigmentt(tan to brown)
Fusobacterium necrophorum	25286	Growth	24 h
Fusobacterium nucleatum **	25586	Growth	24-48 h
Clostridium perfringens **	13124	Growth	24 h	Double zone hemolysis
Peptostreptococcus anaerobius **	27337	Growth	24 h
Staphylococcus aureus     or              Enterococcus faecalis	25923       29212	Growth Growth	24 h 24 h
Escherichia coli	25922	Growth	24 h
Proteus mirabilis	12453	Growth	24 h
Clostridium difficile    or              Propionibacterium acnes	9689       6919	Growth Growth	24 h 24-48 h

         ** Organisms specified by NCCLS for Quality Control testing for Anaerobic Blood Agars

        ^t Pigment production may require more than 48 hours of incubation.

User Quality Control: The final determination to the extent and quantity of user laboratory quality control must be determined by the end user.

If sterility testing is to be performed on this product, the appropriate percentage of the original shipment amount should be incubated anaerobically and aerobically for 48 – 96 hours.

If the nutritive capacity of this media is to be tested for performance, it is recommended that the following ATCC organisms be evaluated for growth.

 

Organism	Expected Growth	Special Reactions
B. fragilis	24 hrs
P. melaninogenica	48 hrs	Pigment
F. nucleatum	24 hrs
C. perfringens	24 hrs	Double zone hemolysis
P. anaerobius	24 hrs

 

Physical Appearance:  CDC should appear opaque burgundy red in color.

 

References

1.        Dowell, V. R., Jr. and T. M. Hawkins.  1974.  Laboratory Methods in Anaerobic Bacteriology.  CDC Laboratory Manual.  USDHEW C. D. C. Atlanta, GA 30333.

 

2.        Dowell, V. R. Jr. and G. L. Lombard.  1977.  Presumptive Identification of Anaerobic Non-sporeforming Gram-negative Bacilli.  USDHEW, CDC, Atlanta, GA 30333.

 

3.   Dowell, V. R., Jr., G. L. Lombard, F. S. Thompson and A. Y. Armfield.  1977.  Media for the Isolation Characterization and Identification of Obligately Anaerobic Bacteria.  USDHEW, CDC, Atlanta, GA 30333.

 

4.        Engelkirk, P. G., Duben-Engelkirk, J. and Dowell, V. R.  1992.  Principles and Practices of Clinical Anaerobic Bacteriology.  Star Publishing Co., Belmont, CA 94002.

 

5.        Jousimeie-Somer, L. V. , Summanen, P. Citron, D. M., Baron, E. J., Wexler, H. M. and S. M. Finegold.  2002.  Wadsworth – KTL Anaerobic Bacteriology Manual.  Star Publishing Co., Belmont, CA 94002.

 

6.        NCCLS.  Quality Control for Commercially Prepared Microbiological Culture Media; Approved Standard- Third Edition.  (2004).  NCCLS document M22-A3.  NCCLS, 940 West Valley Road, Suite 1400, Wayne, PA 19087-1898.