PRAS (Pre-reduced Anaerobically Sterilized) PY-DL-THREONINE media are designed for determination of threonine utilization by anaerobic bacteria.  This biochemical determination is used to aid in the definitive identification of anaerobic bacteria (4).  PY-DL-THREONINE is recommended for use in biochemical utilization done by gas chromatographic methods (4). PY-DL-THREONINE is a non-selective broth medium that was formulated by VPI group to be used in the chromatographic analysis of threonine utilization by an increase in propionic acid.  Appropriate control strains cultured in this medium should show characteristic metabolic products when analyzed using gas chromatography methods. This type of analysis is useful in the identification of clinically significant anaerobic bacteria.  This media is prepared, dispensed, stored and packaged under oxygen-free conditions to prevent the formation of oxidized products prior to use.

Anaerobe Systems PRAS Peptone Yeast Extract

Extract DL-Threonine (PY DL-THREONINE) AS-856

Formula

Pancreatic Digest of Casein, 20.0 g

Yeast Extract, 10.0 g

L-Cysteine, 0.5 g

Hemin (0.1% Soln), 5.0 ml

Vitamin K₁ (1% Soln), 0.1ml

Resazurin, 0.0001 g

Calcium Chloride, anhydrous, 0.008 g

Magnesium Sulfate, anhydrous, 0.008 g

Potassium Phosphate, monobasic, 0.04 g

Potassium Phosphate, dibasic, 0.04 g

Sodium Chloride, 0.08 g

Sodium Bicarbonate, 0.4 g

DL-Threonine, 3.0 g

Distilled Water, 1000.0 ml

 

Final pH 7.1+/- 0.3 at 25 degrees C.

Final volume 7.0 ml +/- 0.7.

 

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 packaging until use.  Avoid overheating or freezing.  Do not use medium if there are signs of deterioration (discoloration or evaporation), oxygen exposure, 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:  1 year from date of manufacture.

 

Procedure

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

Methods for Use:  PY-DL-THREONINE should be inoculated with pure cultures of an organism.  Anaerobically inoculated tubes should be immediately incubated at 35 – 37^oC for 24 – 48 hours, or until sufficient growth is achieved.  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, pipettes, saline blanks, slides, staining supplies, microscope, incinerator/autoclave, incubators, anaerobic chamber, other culture media and serological and biochemical reagents.

 

Limitations

PY-DL-THREONINE will not provide complete information for the identification of bacterial isolates.  Additional test procedures and media are required for complete identification.  Consult reference materials for additional information.

 

Quality Control

Un-inoculated PY-based broths should show only trace amounts, if any, of volatile and nonvolatile fatty acids when tested with gas liquid chromatography as described (1, 4).  This medium, when cultured with appropriate control strains, should show characteristic metabolic products when analyzed using gas chromatography methods.  For interpretation of chromatographic results, consult the VPI manual (4).

PY-DL-THREONINE (CAT # AS-856) is suitable for use in threonine utilization through chromatographic methods; however, Anaerobe Systems’ quality control procedures are limited to growth performance.

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

Organism Tested	ATCC #	Results	Time (Hours)
Bacteroides vulgatus	8482	Growth	24 h
Bacteroides fragilis	25285	Growth	24 h
Prevotella melaninogenica	25845	Growth	24 – 48 h
Fusobacterium necrophorum	25286	Growth	24 – 48 h
Fusobacterium nucleatum	25586	Growth	24 – 48 h
Clostridium perfringens	13124	Growth	24 h
Peptostreptococcus anaerobius	27337	Growth	24 h

 

 

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 medium is to be tested for performance, it is recommended that the following ATCC organisms be evaluated for growth.

 

Organism	Expected
	Growth
B. fragilis	24 hrs
F. necrophorum	24-48 hrs
P. melaninogenica	24-48 hrs
P. anaerobius	24 hrs

 

Physical Appearance:  PY-DL-THREONINE should appear as a clear, golden-yellow liquid within the 16mm x 100mm glass tube.

 

 

 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.        Holdeman, L. V., F. P. Cato and W. E. C. Moore.  1977.  Anaerobe Laboratory Manual.  Virginia Polytechnic Institute and State University.  Blacksburg, VA 24061.

 

5.        Somer-Jousimies, H. R., 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.

 

7.        Isenberg, H. D.  1992.  Clinical Microbiology Procedures Handbook.  American Society for Microbiology Publishing, Washington DC.