Diagnostic device > Diagnostic discs
DIAGNOSTIC DISCS 100 discs Code: DD 501
ITEST BACITRACIN S (0.04 I.U.)
for presumptive identification of beta-hemolytic streptococci of group A
Purpose and usage:
BACITRACIN S diagnostic tests are used for presumptive and easy differentation of beta-hemolythic streptococci, group A, from other groups of beta-hemolythic streptococci.
Principle:
The test utilizes the high sensitivty of beta-hemolythic streptococci of group A to a low concentration of bacitracin (O.O4 I.U.). It is manifested by the formation of an inhibition zone around the ITEST BACITRACIN S disc. Other beta-hemolythic streptococci are resistant to bacitracine concentration.
Technique:
One of the following methods could be used:
Method A: Resuspend 2-3 colonies of the tested strain of beta-hemolythic streptococci in 2 ml of saline. Pour the suspension on a pre-dried blood agar and suck off the residual inoculated substance.Cover the dried-up suspension with a sterile bacitracine disc. Incubate for 17-24 hrs. at 37o C.
Method B: Inoculate the tested strain with a loop on a blood agar and cover it with a sterile bacitracine disc. Incubate for 17-24 hrs. at 37o C.
Evaluation:
Zone diameter (mm) Result
bigger than 10 beta-hemolythic streptococcus of group A
smaller than 10 streptococcus of other serological group
Warning:
1. ITEST BACITRACIN S discs are available in a package of 100 pieces (code No. DD 501) and are designed for diagnostics in vitro only.
2. Store the discs in a dark place at + 4o C and use them until the expiration date marked on the package.
