MGP BROTH

Cat. no. Y25 MGP Broth, 13x100mm Tube, 2ml 20 or 100 tubes/box

INTENDED USE

Hardy Diagnostics MGP Broth is used to differentiate enterococci based on the ability to acidify the carbohydrate methyl-alpha-D-glucopyranoside (MGP).

SUMMARY

Enterococcus faecalis and Enterococcus faecium are becoming more frequently identified as pathogens, particularly in nosocomial infections. The occurrence of vancomycin resistance in these two species has increased in recent years. Enterococcus gallinarum and Enterococcus casseliflavus , while rarely involved in clinical infection, show intrinsic resistance to vancomycin due to the v anC gene. This intrinsic vancomycin resistance makes E. gallinarum and E. casseliflavus difficult to differentiate from the rest of the enterococci by conventional biochemical tests. (1)

Typically, E. gallinarum can be differentiated from E. faecium based on motility, E. gallinarum being motile, while E. faecium is not. However, non-motile strains of E. gallinarum have recently been identified. Correct identification of these strains is critical due to their difference in pathogenicity. E. gallinarum and E. casseliflavus are capable of acidifying methyl-alpha-D-glucopyranoside, but E. faecalis and E. faecium are not. This makes the MGP test useful in preventing the misidentification of vancomycin-resistant E. gallinarum as vancomycin-resistant E. faecium . (2) For a rapid MGP reaction (5 hours), please use our Rapid MGP Medium (Cat. no. Z225).

FORMULA

Ingredients per liter of deionized water:*

Pancreatic Digest of Casein 10.0gm
Methyl-alpha-D-glucopyranoside 10.0gm
Sodium Chloride 5.0gm
Phenol Red 18.0mg

Final pH 7.4 +/- 0.2 at 25ºC.

* Adjusted and/or supplemented as required to meet performance standards.

STORAGE AND SHELF LIFE

Storage: Upon receipt store at 2-8ºC. away from direct light. Media should not be used if there are any signs of deterioration, discoloration, contamination, or if the expiration date has passed. Product is light and temperature sensitive; protect from light, excessive heat, moisture, and freezing.

PRECAUTIONS

PROCEDURE

1. Inoculate the MGP Broth by lightly touching a single, isolated colony. Do not use a heavy inoculum with this product.

2. Incubate aerobically at 35ºC. for 24 hours.

3. Observe for yellow color change in the media.

INTERPRETATION OF RESULTS

A yellow color change is a positive test for acidification of MGP. Red or orange colored media is a negative test.

Typical results are as follows: (1)

E. gallinarum MGP-positive
E. casseliflavus MGP-positive
E. flavescens MGP-positive
E. faecalis MGP-negative
E. faecium MGP-negative
E. mundtii MGP-negative
E. durans MGP-negative
E. hirae MGP-negative

LIMITATIONS

A heavy inoculum may give false-positive results.

Extended incubation times may result in false-positive reactions.

MGP Broth is used to aid in the differentiation of the enterococci. Additional biochemical tests are required for complete identification. See listed references for more information. (1-6)

MATERIALS REQUIRED BUT NOT PROVIDED

Standard microbiological supplies and equipment such as loops, other culture media, swabs, applicator sticks, incinerators, and incubators, etc., as well as serological and biochemical reagents, are not provided.

QUALITY CONTROL

Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Enterococcus gallinarum
ATCC ® 49573
A 24hr 35°C Aerobic Growth; media turns yellow
Enterococcus faecalis
ATCC ® 29212
A 24hr 35°C Aerobic Growth; no color change

User Quality Control

PHYSICAL APPEARANCE

MGP Broth should appear clear with a slight opalescence, and red in color.

E. gallinarum growing in MGP Broth

Enterococcus gallinarum (ATCC ® 49573) growing in MGP Broth (Cat. no. Y25). Incubated aerobically for 24 hours at 35ºC.

E. faecalis growing in MGP Broth

Enterococcus faecalis (ATCC ® 29212) growing in MGP Broth (Cat. no. Y25). Incubated aerobically for 24 hours at 3ºC.

MGP Broth

Uninoculated tube of MGP Broth (Cat. no. Y25).





REFERENCES

1. Devriese, L.A., et. al. 1996. J. Clinical Micro.; 34: 2607-2608.

2. Turenne, C.Y., et. al. 1998. J. Clinical Micro.; 36:2333-2335.

3. Gin, A.S. and G.G. Zhanel. 1996. Vancomycin-Resistant Enterococci. The Annals of Pharmacotherapy.; 30:615-624.

4. Facklam, R.R. and M.D. Collins. 1989. Identification of Enterococcus species isolated from human infections by a conventional test scheme. J. Clinical Micro.; 27:731-734.

5. Jorgensen., et al. Manual of Clinical Microbiology, American Society for Microbiology, Washington, D.C.

6. Tille, P., et al. Bailey and Scott's Diagnostic Microbiology, C.V. Mosby Company, St. Louis, MO.


ATCC is a registered trademark of the American Type Culture Collection.

031016gr