ERP Micro December 2019

B astin et al . : J ournal of AOAC I nternational V ol . 101, N o . 5, 2018  1599

Table 2017.09G. Summary of results for the identification of Gram-negative organisms: Cronobacter exclusivity

MALDI Biotyper correctly identified

MALDI Biotyper incorrectly identified

Ref. correctly identified

Ref. incorrectly identified

Selective media no growth

MALDI Biotyper total

Organism

Ref. total

C. farmeri ATCC 51633 C. freundii QL11007.10 E. coli ATCC 10536 Hafnia alvei ATCC 51815 Klebsiella pneumoniae ATCC 10031 ATCC 10031 Pseudomonas aeruginosa ATCC 35032 S. Hadar ATCC 51956 S. marcescens QL11007.1

42 40 42 42

12 14 13 14

0 0 0 0

2 0 1 0

0 2 0 0

42 40 42 42

14 14 14 14

36

14

0

0

6

36

14

42

10

0

4

0

42

14

37 41

14 14

0 1 1

0 0 7

5 0

37 42

14 14

323 a

112 b

Total isolates

322

105

13

a The total numbers represent isolates analyzed on the three recommended culture medias: Tryptic Soy Agar, Chromogenic Cronobacter Isolation Agar, and Enterobacter sakazakii Isolation Agar. b Reference method performed from Tryptic Soy Agar plates only.

Table 2017.09H. Summary of results for the confirmation of Gram-negative organisms: Cronobacter exclusivity

MALDI Biotyper correctly confirmed

MALDI Biotyper incorrectly confirmed

Ref. correctly confirmed

Ref. incorrectly confirmed

Selective media no growth

MALDI Biotyper total

Organism

Ref. total

C. farmeri ATCC 51633 C. freundii QL11007.10 E. coli ATCC 10536 H. alvei ATCC 51815

42 40 42 42 36 42 37 42

12 14 13 14 14 10 14 14

0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0

0 2 0 0 6 0 5 0

42 40 42 42 36 42 37 42

14 14 14 14 14 14 14 14

K. pneumoniae ATCC 10031 P. aeruginosa ATCC 35032 S. Hadar ATCC 51956 S. marcescens QL11007.1

323 a

112 b

Total isolates

323

112

13

a The total numbers represent isolates analyzed on the three recommended culture medias: Tryptic Soy Agar, Chromogenic Cronobacter Isolation Agar, and Enterobacter sakazakii Isolation Agar. b Reference method performed from Tryptic Soy Agar plates only.

( j )  Internal positive E. coli DNA: Bacterial Test Standard (BTS) .—Cat. No. 8255343. Additional items required ( k )  Incubators .—Capable of maintaining temperatures of 34–38ºC. ( l )  Adjustable, variable-volume pipets .—Capable of sampling and delivering 1–1000 μL. ( m )  Micropipette tips .—Aerosol-resistant. ( n )  Refrigerator .—Capable of maintaining 2–8°C. ( o )  Freezer. —Capable of maintaining –20°C. ( p )  TSA. ( q )  XLD. ( r )  BGSA . ( s )  RSA. ( t )  ASAP. ( u )  Brilliance Salmonella Agar (BSA, Thermo Fisher Scientific). ( v )  ESIA. ( w )  Chromogenic Cronobacter Isolation Agar (CCI).

( x )  Vortex mixer. ( y )  Bench-top microcentrifuge .—Capable of 15871 to 21130 g , equivalent to 13000 to 15 000 rpm for Eppendorf tube centrifuged with a 5424R rotor. ( z )  Standard solvent (acetonitrile 50%, water 47.5%, and trifluoroacetic acid 2.5%). ( aa )  HPLC grade water. ( bb )  Formic acid. ( cc )  McFarland standards. ( dd )  Absolute ethanol. ( ee )  8MGuanidine Hydrochloride (GdnHCl) .—Commercially available. ( ff )  Trifluoroacetic acid.

( gg )  Colony-transfer device. ( hh )  Sterile inoculation loops. ( ii )  1.5 mL Microcentrifuge tubes.

( jj )  Fiber-free cloth .—For cleaning MSP 96 target polished steel BC (Cat. No. 8280800) or MSP 48 target polished steel BC (Cat. No. 8281817) only.