Methods to be Reviewed by OMB in 2016

rowley

et al

ournal of

AOAC I

nternational

95, N

. 5, 2012

1429

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.

-hemolysis is

observed, further testing must be performed to exclude

Listeria

monocytogenes.

Reference:

J. AOAC Int.

, 1427(2012)

Results

In the collaborative study, a total of 720 isolates were analyzed

representing 12 different inclusivity species and 120 isolates

screened representing six different exclusivity species. Twenty

laboratories representing government, industry, and private

testing laboratories throughout the United States participated.

The individual isolate results for both inclusivity and exclusivity

reported by each laboratory are presented in Tables 3 and 4,

respectively. Tables

2011.02A

and

2011.02B

present a summary

of the collaborative study including the number of isolates

identified correctly, misidentified, unidentified, or not tested.

For the purposes of this collaborative study, an unidentified or

misidentified isolate was considered a missed identification.

Discussion

Inclusivity

For the inclusivity evaluation, each laboratory identified

isolates from CBA, TSA, and TSAB subculture media for each

of the 12 claimed species. All of the collaborators completed all

of the isolates submitted. A total of 714 strains were identified

correctly by theVITEK 2 GPmethod. Six isolates were not tested

by the VITEK 2 GP method due to being excluded by Gram

stain reactions. For

L. innocua

, Laboratory 3 reported a low

discrimination between

L. innocua

and

welshimeri

on TSA

only. Laboratories 2, 3, 11, and 13 reported low discrimination

between

seeligeri, L. ivanovii,

and

L. welshimeri

on either

CBA or TSAB for

L. seeligeri

. Laboratories 6, 10, 11, and

14 reported low discrimination between

L. innocua

and

L. welshimeri

for

L. welshimeri

on TSA or TSAB. Laboratories

10, 11, and 18 reported low discrimination between

S. aureus

and

S. intermedius

for

S. aureus

on TSAB only. As indicated

in the VITEK 2 GP method, a low discrimination result

is considered a correct identification. Supplemental tests

recommended on the result printout were conducted to provide

a correct final identification of the species. There were zero

isolates that produced a misidentified or an unidentified result

for the inclusivity panel.

Exclusivity

For the exclusivity evaluation, each laboratory received

six nontarget species that consisted of three Gram-negative

bacteria, one

Bacillus

, one yeast, and one mold. All of the

collaborators completed all of the isolates submitted. Of the

120 isolates screened, 106 were correctly excluded. A total of

14 isolates were incorrectly characterized as a Gram-positive

organism resulting in improper analysis and misidentification

by VITEK 2 GP. Laboratories 1, 2, 5, 7, 8, 10, 11, 15, and

18 characterized

B. coagulans

as a Gram-positive or a Gram-

positive with endospores and resulted in an Unidentified

Organism reported by the VITEK 2 GP method. This is

due to the fact that Bacilli are not covered in the scope of

the VITEK 2 GP test system. Laboratory 13 characterized

B. coagulans

as Gram-positive cocci and reported the

VITEK 2 GP results as

Streptococcus mitis

. Laboratories 10 and

14 characterized

Escherichia coli

as a Gram-positive organism

and reported the VITEK 2 identification as Unidentified

Organism. Laboratories 1 and 8 incorrectly characterized

Candida albicans

as a Gram-positive organism and reported

the VITEK 2 identification as

Kocuria varians

Recommendations

It is recommended that the VITEK 2 GP test card method be

adopted as Official First Action for the identification of selected

Gram-positive bacterium.

Acknowledgements

We would like to extend a sincere thank you to the following

collaborators for their dedicated participation in this study:

John Mills, Judith Colón-Reveles, and Hari P. Dwivedi,

bioMérieux Industry, Hazelwood, MO

Yvonne Salfinger, Sun Kim, Patricia Hanson, and Jason

Crowe, Florida Department of Agriculture and Consumer

Services, Tallahassee, FL

Tom Sidebottom and Carol Elems, FDA San Francisco

District Office, Alameda, CA

Maureen Coakley, Jennifer Canale, and Gloria Parra, FDA

Northeast Regional Laboratory, Jamaica, NY

Sung Guk Kim and Latriana Robertson, FDANational Center

for Toxicological Research, Jefferson, AR

Hua Wang, FDA Center for Food Safety and Applied

Nutrition, College Park, MD

Leeann Johnson and Bryanne Shaw, Minnesota Department

of Agriculture, St. Paul, MN

Denise Toney and Marta Segarra, Division of Consolidated

Laboratory Services, Richmond, VA

Debra Cherney and Joanne Ruebl, Cherney Microbiological

Services, Ltd, Green Bay, WI

Melinda Hayman, April Garza, and Sergio Montez, Food

Safety Net Services, Ltd, San Antonio, TX

Jayne Finnigan and Peter Wikoff, New Hampshire Public

Health Laboratories Food Safety Micro/Rabies Unit, Concord,

Pete Dombroski, Illinois Department of Public Health

Laboratory Springfield Combined Laboratory Facility,

Springfield, IL

Mary Ann Murphy, Jackie Glover, and Rebecca Daugherty,

U.S. Department of Agriculture-Agricultural Marketing

Service, National Science Laboratory, Gastonia, NC

Karen Wilson and Sheri Robeson, Michigan Department of

Agriculture, Lansing, MI

Adam Miller, Rhode Island Department of Health

Laboratories, Providence, RI

Jessica Dyer and Urvashi Patel, North Carolina Department

of Agriculture, Food and Drug Protection Division, Raleigh, NC

Candidates for 2016 Method of the Year

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