Liquid Dental Transport (LDT) is a mineral salt base liquid with reducing agents designed as a holding medium for maintaining viability of microorganisms, especially anaerobic bacteria through collection, transport and shipment of clinical specimens. Buffered mineral salts with sodium thioglycolate and L-cysteine are added to provide a reduced environment. This combination has been prepared to provide an environment that maintains viability of most microorganisms without significant multiplication and allows for dilution of inhibitors present in clinical material. This medium is designed to meet the stringent viability requirements of obligate anaerobes Item is supplied in 19 x 40 mm tube with screw caps containing rubber septa (Hungate caps), which allow for either direct injection of aspirated clinical material or introduction of tissue samples. This medium is prepared, dispensed and packaged under oxygen-free conditions to prevent the formation of oxidized products prior to use.

 Anaerobe Systems PRAS Liquid Dental Transport
                        Medium (LDT) AS-916

 

View the full product insert: LDT insert.pdf

Formula

Magnesium Sulfate, heptahydrate, 0.1 g

Potassium Phosphate, monobasic, 0.2 g

Potassium Chloride, 0.2 g

Sodium Chloride, 3.0 g

Sodium Phosphate, diabasic, 1.15 g

Sodium Thioglycolate, 1.0 g

L-Cysteine, 0.5 g

Distilled Water, 1000.0 ml

 

Final pH 7.3 +/- 0.3 at 25 degrees C.

Final volume 1.0 ml +/- 0.2.

 

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) 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:               AS-916                                   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:  LDT, AS-916, is suitable for use as a transport and holding medium for clinical specimens collected on paper points or fluid specimens aspirated into syringes.  With any clinical specimen, LDT should be inoculated by aseptic technique immediately at or after collection.  For paper point collection, open tube by screw cap and drop the paper point into the liquid medium.  Immediately close tube.  Contact with air of tube contents should be minimized.  For syringe specimens, the rubber septum in the cap should be disinfected and the fluid specimen directly injected into the tube at a slow rate.  Once inoculated, keep at room temperature and deliver to the laboratory for processing as soon as possible.  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, paper points, disinfectant, syringes with needles, sterile forceps, saline blanks, slides, staining supplies, microscope, incinerator/autoclave, incubators, anaerobic chamber or jars, other culture media and serological and biochemical reagents.

 

Limitations

LDT is designed as a holding medium to maintain viability of microorganisms contained within a specimen during transport.  This medium will not provide complete information for identification of bacterial isolates.  Additional test procedures and media are required for complete identification.  Specimens should be transported and processed in the laboratory in a timely manner since delay may result in overgrowth by one organism present in a specimen from polymicrobic infections.  Consult reference materials for additional information.

 

Quality Control

If used properly, this medium should maintain the viability of microorganisms present within a clinical specimen until transported and processed within the laboratory.

The following organisms are routinely used for quality assurance testing at Anaerobe Systems.  For determining viability of the organisms listed below, each ATCC strain is inoculated into a LDT tube and held overnight.  In an anaerobic environment, each organism is streaked, onto Anaerobic Brucella Blood Agar, to obtained isolated colonies.  Plates are incubated for 35 –37^oC for 48 hours, and growth is observed. 

Organism Tested	ATCC #	Results	Time (Hours)
Bacteroides fragilis	25285	Growth	24 h
Prevotella melaninogenica	25845	Growth	24 – 48 h
Bacteroides vulgatus	8482	Growth	24 h
Fusobacterium nucleatum	25586	Growth	24 h
Fusobacterium necrophorum	25286	Growth	24 h
Clostridium perfringens	13124	Growth	24 h
Clostridium novyi	7659	Growth	24 – 48 h
Peptostreptococcus anaerobius	27337	Growth	24 h
Fusobacterium periodonticum	33693	Growth	24  - 48 h
Porphyromonas gingivalis	25586	Growth	24 – 48 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 holding capacity of this media is to be tested for performance, it is recommended that the following ATCC organisms be evaluated for growth. 

Organism	Growth in
	Hours
B. fragilis	24 hrs
P. melaninogenica	24-48 hrs
F. necrophorum	24 hrs
F. periodonticum	24-48 hrs
P. gingivalis	24-48 hrs

 

Physical Appearance:  LDT should appear as a clear liquid within a 19mm x 40mm 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.        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.        Holdeman, L. V., F. P. Cato and W. E. C. Moore.  1977.  Anaerobe Laboratory Manual.  Virginia Polytechnic Institute and State University.  Blacksburg, VA 24061

 

6.        Jousimies-Somer, 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.

 

7.        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.