AOAC RI ERP Final Action Recommendations eBook

( c )  Caution : Dispose of all reagents and other contaminated materials by acceptable procedures for potentially biohazardous materials. All microbial cultures are potentially infectious and should be treated with universal precautions. ( d ) Store VITEK 2 GP cards at 2–8°C. ( e ) Do not freeze test cards. ( f ) Bring reagents to room temperature before inserting them into the VITEK 2 instrument. ( g ) Return unused cards to 2–8°C immediately after use. Note :  A Gram stain should be performed to determine a pure culture’s Gram reaction and morphology prior to selecting which VITEK 2 identification card to inoculate. Interpretation of test results requires the judgment and skill of a person proficient in Gram staining and knowledgeable in the interpretation of the Gram reaction and morphology of microorganisms. D. Preparation of Test Suspension ( a ) Aseptically transfer 3.0 mL sterile saline (aqueous 0.45 to 0.50% NaCl, pH 4.5–7.0) into polystyrene test tubes (12×75 mm). Do not use glass tubes. ( b ) Using a sterile stick or swab, transfer a sufficient number of colonies from a 24 h culture on recommended culture medium to the saline tube to achieve a density equivalent to McFarland 0.50 to 0.63 with the VITEK 2 DENSICHEK. ( c ) Test the cultures by the VITEK 2 GP method within 30 min of preparation of the suspended culture. ( d ) Insert the culture tube and the VITEK 2 GP card into the VITEK 2 cassette and refer to the User Manual (to be provided with the instrument) for instructions on use of the instrument. ( e ) Report identification results from the VITEK 2 system. ( f ) As indicated in theVITEK 2 GPproduct information provided to end-users, slashline or low discrimination identifications are acceptable results for the VITEK 2 GP method that require supplemental tests to further resolve the organism identification. E. Results and Interpretation The results are interpreted by the VITEK 2 system. Printed results will indicate a high probability match to a single species if a unique identification pattern is recognized. If a unique pattern is not recognized, the system will suggest supplemental tests to distinguish between two or three closely related organisms, or indicate the result as an unidentified organism (either >3 organisms can exhibit the observed pattern, or the biopattern is very atypical and is not represented in the database). It is recommended that hemolysis on blood agar is reviewed for any identification of Listeria innocua. If b -hemolysis is observed, further testing must be performed to exclude Listeria monocytogenes. Reference: J. AOAC Int. 95 , 1425(2012)

Table 2012.02C. Biochemical tests included in the VITEK 2 GP card Well Test Abbreviation 2 D-Amygdalin AMY 4 Phosphatidylinositol phospholipase C PIPLC 5 D-Xylose dXYL 8 Arginine dihydrolase 1 ADH1 9 b -Galactosidase BGAL 11 a -Glucosidase AGLU 13 Ala Phe Pro arylamidase APPA 14 Cyclodextrin CDEX 15 L-Aspartate arylamidase AspA 16 b -Galactopyranosidase BGAR 17 a -Mannosidase AMAN 19 Phosphatase PHOS 20 Leucine arylamidase LeuA 23 L-Proline arylamidase ProA 24 b -Glucaronidase BGURr 25 a -Galactosidase AGAL 26 L-Pyrrolidonyl-arylamidase PyrA 27 b -Glucaronidase BGUR 28 Alanine arylamidase AlaA 29 Tyrosine arylamidase TyrA 30 D-Sorbitol dSOR 31 Urease URE 32 Polymixin B resistance POLYB 37 D-Galactose dGAL 38 D-Ribose dRIB 39 L-Lactate alkalinization ILATk 42 Lactose LAC 44 N -Acetyl-D-glucosamine NAG 45 D-Maltose dMAL 46 Bacitracin resistance BACI 47 Novobiocin resistance NOVO 50 Growth in 6.5% NaCl NC6.5 52 D-Mannitol dMAN 53 D-Mannose dMNE 54 Methyl-B-D-glucopyranoside MBdG 56 Pullulan PUL 57 D-Raffinose dRAF 58 O/129 Resistance (comp.vibrio.) O129R 59 Salicin SAL 60 Saccharose/sucrose SAC 62 D-Trehalose dTRE 63 Arginine dihydrolase 2 ADH2s 64 Optochin resistance OPTO

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