PCA + TTC + Neutralizing / Vogel Johnson Agar dipslide is a ready-to-use device with two different media coated onto a plastic support used for the microbial monitoring of surfaces and liquids even in the presence of residues of disinfectants. The selective medium allows the isolation and enumeration of coagulase-positive, mannitol-utilizing staphylococci. The other medium is used for enumeration of bacteria.

TEST PROCEDURE

1. Take a slide from the refrigerator and leave it at ambient temperature for about 5 minutes.
2. Unscrew and extract the slide from its cylindrical container. Avoid any contact with the agar surface.
3. For surface monitoring, flex the cap forming a 90° angle and press each side of the slide firmly against the surface to be examined for 10 seconds. Alternatively, use a swab for sampling the area, afterwards roll the swab gently over the agar surface. For examination of liquids, hold the slide by the cap and immerse it completely into the test fluid.
4. Reinsert the slide into its tube, screw it tight and incubate at 35 ± 2°C for 24 h. Record the count on Vogel Johnson Agar prior to continue incubation at 30 ± 1°C for other 48 h.

RESULTS INTERPRETATION

Count the total number of colonies on PCA + TTC + Neutralizing (Side 1) to obtain the total bacterial count.

Organisms that grow as black colonies surrounded by a yellow zone on Vogel Johnson Agar (Side 2) may be presumed to be Staphylococcus aureus. Prolonged incubation may result in the growth of black coagulase- negative colonies and if these organisms also ferment mannitol they may be falsely identified from their appearance as S. aureus. In these circumstances further tests are necessary for final identification.

APPEARANCE

Side 1. Slightly opalescent, light amber.

Side 2. Slightly opalescent, red.

STORAGE CONDITIONS

10-25°C away from light, until the expiry date on the label. Eliminate if signs of deterioration or contamination are evident.

SHELF LIFE

6 months