Atlas page 50-1

CHEM: Various tests done in an 18 hr overnight period for Gram negative oxidase negative rods provides a 5 digit Identicode which can be used to identify to Genus and species.

INOC: Enterotube needle smear (DO NOT heat the needle it is sterile). Remove the BLUE cap and grasp the wire handle. Use the needle to pick-up as much of your unknown as you can; insert in a "twisting motion 3x; on the 4th withdrawal, line-up the "score" on the needle with the threads of the tube and break the wire. Replace the Blue cap (DO NOT LAY DOWN THE Wire).  Use the wire to punch aerobic holes in the first 8 chambers from the White cap end on the opposite side of the label (NOTE the "horse-shoe shaped" punch locations; discard the needle-handle in the Biohazard trash

INCUB: 18-24 hrs at 37 C

EVAL: Use the "key chart (below) and a IDENTICODE Score Sheet (below)" to determine the Pos/Neg chambers by color - circle the positive numbers of each and add those within a bracket together - bring each bracket total down to a square of Identicode (don't forget to record gas or not in the first 3 chambers by looking for bubbles or separation by the paraffin from the agar chamber).  AFTER recording the color changes, turn the tube round side down (bottom up) and add 1 drop of Kovac's to the Indole chamber (pink liquid = +), add 1 drop of VP1 plus 1 drop of VP2 to VP chamber - record elsewhere (pink = +). KEEP TUBE LEVEL WHILE ADDING REAGENTS AND AFTER UNTIL DISCARD.

Obtain the IDENTICODE-book and lookup the IDENTICODE provided by the 5 digit sum.

CAUTIONS: ONLY for Gram neg oxidase neg rods; do not heat the needle; be sure and punch the aerobic chambers; DO NOT PUNCH the "ASS" of the tube; RECORD colors BEFORE adding drops.  Keep level after adding drops to the "ASS" of the tube (bottom); use a pencil or pen to "punch" the hole in the bottom for the IND and VP reagents.  DISCARD TUBE IMMEDIATELY AFTER READING IN THE BIOHAZARD TRASH!


The Enterotube II is a commercial product available from Becton-Dickinson and Company for identification of enteric Gram-negative OXIDASE negative intestinal bacilli. The OXIFERM II TUBE SYSTEM (see button below) is utilized for Gram-negative OXIDASE positive rods.  Its twelve small compartments substitute for twelve test tubes containing appropriate media for these tests: glucose, lysine, ornithine, H2S/indole, adonitol, lactose, arabinose, sorbitol, Voges-Proskauer, Dulcitol/PA, urea and citrate.

Under the light BLUE colored cap of the enterotube you will find a wire handle (DO NOT FLAME THE WIRE - it is sterile).  The sterile wire inserted in the Enterotube is used to obtain growth from an isolated colony of the test organism. The wire is pushed down through the twelve compartments in a twisting motion (3X do not remove wire between times) inoculating each test as it proceeds.  Break the wire at the "score" on the wire on the third insertion and use it to punch a hole in the first 8 compartments at the "windows."  Re-cap the Enterotube.  If your Enterotube has a removable paper cover for holes for these chambers you do not need to punch them with the wire... just, pull the paper strip off the tube after inoculation.  Label the tube with the date and incubate "flat side-down." 

Results are recorded after 18 to 24 hours of incubation using a specific form (see below) and reference Identicode Guidebook. Remember to record the chamber colors immediately after incubation and BEFORE adding the reagents for the indole and VP test as these reagent change chamber colors.  Look for bubbles of gas trapped against the bottom of the first three chambers. 

Kovacs and VP Reagents should be added to those chambers by piercing the plastic wrapping with a pen and adding one drop to those chamber - observe for a pink color change...

Discard of the wire and the entire enterotube in a suitable BIOHAZARD container when you are finished...

1. Enterotube
ready for inoculation
2. Enterotube results