Can anyone help me that which tests can i use for identification of lactic acid bacteria. Can mannitol salt agar test be used for lactobacilli or MSA is only used as a selective media for growth of Staphylococcus aureus ? need urgent help.
Thankyou.
Samiya Siddiqui You can refer Bergey’s manual of systemic bacteriology. Use MRS agar for the selective growth of lactobacillus. Incubate in 37 °C for 48 hours. You can do
- Gram staining
- Catalase test
- Citrate utilization test
- Voges-Proskauer test
- Indole test
- Methyl red test
- oxidase test to identify lactobacillus.
Dear,
The mannitol salt agar contents tow inhibition factor for bacteria (Mannitol and 75 gm of NaCl) but some species of lactobacilli can grow on this media . you can use Catalase test, Staphylococcus aureus is positive but lactobacilli is negative.
Characterization, of isolated strains through morphological, physiological, biochemical tests such as catalase, oxidase and IMVIC ( indole, methyl - red, voges proskauver, citrate utilization ) test. Carbohydrate such as glucose, xylose, galactose, fermentation test should be performed and the result should show positive reaction. The isolated Lactobacillus should be resistant to inhibitory substances like NaCl ( 1 - 9% ) and bile acid ( 0.05 - 0.3% ). For more details consult Asian j. of Biological Sciences. Vol. 9 (1 ); 1 - 9, 2016
I just add, applying use different sugars to answer of Soundarya Priya and use of 30 percent of H2O2 and adding oil to your mannitol salt agar to create anaerobic condition to answer Alaa Kareem Niamah .
Also you have to use coagulase test for detecting S.aureus.
I used MRS agar and my strain showed growth on MRS agar .In addition i performed catalase and oxidase test both were found out to be negative. IMViC tests should be positive for lactobacilli?
my strain showed very slow growth on mannitol salt agar ,it took about 48-72 hrs for my isolate to grow on it. So this can be used as an identification test then
Sylvester peter Antai Sir i tried using lactose agar plate for my isolate but it showed almost negligible growth even after 48-72 hrs. Being a lactic acid bacteria should it must hydrolyse lactose or it can also be negative for lactose utilization.
Thankyou, i shall test different carbon sources now.
Alireza Mordadi 30% H2O2 and oil should be added to mannitol salt agar after autoclaving? Kindly explain it a little bit more.
Thankyou.
Just S.aureus have positive reaction in catalase test with 30 percent of H2O2.
About oil, you made your medium in a tube(glass one) and culture your bacteria on it then added sterile oil.
It was clear?
I recommend that You make a preliminary catalasa test, than API 50 CH in conduction with API 50 CHL for biochemical test_study of carbohydrate metabolism.
Recuento de Lactobacillus spp. en agar MRS, Morfología, coloración Gram negativos (-), Producción de ácido sulfhídrico (-) Catalasa (-), Indiol (-), Reducción de nitratos (-), coagulación en leche (+) 48h /37°C.
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