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The BBL Crystal™ Rapid Gram-Positive (RGP) Identification System (ID) is a miniaturized identification method employing modified conventional, fluorogenic and chromogenic substrates. It is intended for the identification of aerobic gram-positive bacteria.^1,2,13,16

Micromethods for the biochemical identification of microorganisms were reported as early as 1918.³ Several publications reported on the use of the reagent-impregnated paper discs and micro-tube methods for differentiating enteric bacteria.^3,4,7,17,19 The interest in miniaturized identification systems led to the introduction of several commercial systems in the late 1960s, and they provided advantages in requiring little storage space, extended shelf life, standardized quality control and ease of use.

In general, many of the tests used in the BBL Crystal ID Systems are modifications of classical methods. These include tests for fermentation, oxidation, degradation and hydrolysis of various substrates. In addition, there are chromogen and fluorogen linked substrates, as in the BBL Crystal RGP ID panel, to detect enzymes that microbes use to metabolize various substrates.^{5,7,8,9,11,12,14,15}

The BBL Crystal™ RGP ID kit is comprised of (i) BBL Crystal RGP ID panel lids, (ii) BBL Crystal bases and (iii) BBL Crystal™ ANR, GP, RGP, N/H ID Inoculum Fluid (IF) tubes. The lid contains 29 dehydrated substrates and a fluorescence control on tips of plastic prongs. The base has 30 reaction wells. Test inoculum is prepared with the inoculum fluid and is used to fill all 30 wells in the base. When the lid is aligned with the base and snapped in place, the test inoculum rehydrates the dried substrates and initiates test reactions.

Following an incubation period, the wells are examined for color changes or presence of fluorescence that result from metabolic activities of the microorganisms. The resulting pattern of the 29 reactions is converted into a ten digit profile number that is used as the basis for identification.¹⁸ Biochemical and enzymatic reaction patterns for the 29 BBL Crystal RGP ID substrates for a wide variety of microorganisms are stored in the BBL Crystal RGP ID data base. Identification is derived from a comparative analysis of the reaction pattern of the test isolate to those held in the database. A complete list of taxa that comprises the current database is provided in Table 1 (see pg. 7).

Quality control testing is recommended for each lot of panels as follows –

1. Inoculate a panel with Streptococcus pyogenes ATCC^® 19615 per recommended procedure (refer to "Test

Procedure").

2. Prior to incubation, let panel remain at room temperature for 1 min (not more than 2 min).

3. Read and record reactions with the aid of the panel viewer and color reaction chart.

4. If any of the wells (except 1J) are positive per color reaction chart (after 1 – 2 min), DO NOT USE PANELS from this lot. Contact Becton Dickinson Technical Services.

NOTE: Well 1J can appear positive upon rehydration; this is not indicative of a problem.

5. If all wells are negative, then incubate panel for 4 h at 35 – 37°C.

6. Read panel with the panel viewer and color reaction chart; record reactions using the results pad.

7. Compare recorded reactions with those listed in Table 4 (see pg. 10). If discrepant results are obtained, confirm purity of quality control strain before contacting Becton Dickinson Technical Services.

8. The incubator door should not be opened repeatedly during the incubation period (preferably less than 3 times).

Expected test results for additional quality control test strains are listed in Table 5 (see pg. 10).

The BBL Crystal RGP ID panel contains 29 enzymatic and biochemical substrates. Refer to Table 3 (see pg. 9) for a list of active ingredients.

Precautions: in vitro Diagnostic

After review by the U.S. Centers for Disease Control and Prevention (CDC), and the Food and Drug Administration (FDA) under CLIA '88, this product has been identified as high complexity. The CDC Analyte Identifier Code is 0412; the CDC Test System Identifier Code is 07920.

After use, all infectious materials including plates, cotton swabs, inoculum fluid tubes, and panels must be autoclaved prior to disposal or incineration.