cetrimide agar (Oxoid) and confirmed by standard biochemical tests such as catalase, oxidase and indole tests
They were positive for citrate, methyl red, Voges-Proskaner and starch hydrolysis tests, but were negative for Indole test
and lactose fermentation.
BSH 3a (Lactobacillus sp.) identified on the basis of biochemical tests whose antibacterial activity measured through inhibition zone was of 2 mm found to be negative for indole test
(green layer at the top of test tube) and starch agar test.
These were used to obtain additional cultures and further characterize the bacterial colonies by Gram staining, motility, oxidase, and indole tests
Salmonella colonies were identif ied using standard biochemical tests including fermentation of glucose negative urease reaction lysine decarboxylase negative indole test
H2S production and fermentation of dulcitol.
Biochemical Tests such as Catalase Test, TSI Test, MRVP Test and Indole Test
were also performed for further confirmation of E.coli.
to produce pink colonies (emphasising the importance of a spot indole test
) (10-12,17); the ability of E.
They included: Indole test
, methyl red test (MR), citrate utilization, catalase test, oxidase test, coagulase test, oxidation--fermentation test, fermentation of sugars, and motility test.
Motility test and indole test
were carried out by inoculating the culture into the motility indole lysine agar slant procured from Hi-Media Pvt.
All blue colonies are counted as presumptive E.coli, with confirmation requiring a simple indole test
The spot indole test
was also positive and confirmatory of the identification.
Selected colonies were sub-cultured for purity onto Levine EMB and Columbia 5% sheep blood, and isolates underwent biochemical testing, including the indole test
, which with colonial morphology is a presumptive test for Escherichia coli (N=28), plating on differential media (Rainbow Agar) specific for Shiga toxin producing Escherichia coli (N=17), and latex agglutination tests specific for O157 and H7 antigens (N=17) to confirm Escherichia coli O157:H7.