Dear Sherlyn Tang,

you can see the images in this reference to detection your results 

http://www.medical-labs.net/different-types-of-bacterial-hemolysis-on-blood-agar-788/

Dear Sherlyn,

If I am not making any mistake in reading from your images of culture streaks on sheep blood agar then:

1: shows partial hemolysis of RBCs  (greenish discoloration) and thus it is alpha heamolytic bacterial culture.

3 and 6: show complete hemolysis of RBCs (clear zone) and thus they are beta heamolytic bacterial cultures and

2, 4 and 5: show no heamolytic action on RBCs (i.e.RBCs of sheep blood in the agar medium are not affected and thus gamma heamolytic bacterial cultures; meaning no heamolytic action.

Hi

Species of Streptococcus are classified based on their hemolytic properties.

Alpha-hemolytic species cause oxidization of iron in hemoglobin molecules within red blood cells, giving it a greenish color on blood agar.

 Beta-hemolytic species cause complete rupture of red blood cells. On blood agar, this appears as wide areas clear of blood cells surrounding bacterial colonies.

 Gamma-hemolytic species cause no hemolysis

Patterson MJ (1996). Baron S; et al., eds. Streptococcus. In: Baron's Medical Microbiology (4th ed.). Univ of Texas Medical Branch. (via NCBI Bookshelf) ISBN 0-9631172-1-1.

Hi Awatif Hameed Issa, thanks for reply. I have tested against Lactobacillus and I notice majority is showing alpha haemolysis. But Lactobacillus is consider probiotic which is safe for consumption. Do you think if in this case, it is concluded as risky? 

Hi Arun Padhye, all these strains are lactobacillus, I had checked on its safety data and showed biosafety level 1. Do you think it is possible to be alpha and beta? 

Dear Sherlyn,

As Kais has mentioned yo can also refer yourself to the reference images from the link provided and would come to a logical conclusion as I have mentioned above that bacterial culture at No.1 is alpha heamolytic. Culture No. 3 and 4 are beta heamolytic and remaining cultures at No. 2, 5 and 6 show no heamolysis and therefore are considered as belonging to gamma heamolytic category.

Also confirm that although all six cultures are Lactobacilli whether they belong to the same species of Lactobacillus. It is quite possible that bacterial culture from same Genus and species  would behave differently on blood agar as certain strains show different behavior.

Another point to be considered here is this that heamolysis as bio-chemical test is important in case of certain bacteria such as Streptococci, Bacillus cereus, etc. It's significance is important from two points of view. 1) As one of the  important bio-chemical test for identification and/or classification for certain bacteria only. 2) For pathogens responsible for skin lesions, boils etc. such as Streptococcus and Staphylococcus it is quite possible and truly they are heamolytic mostly beta heamolytic or alpha type and as you can see that this is quite logical as these bacteria are parasitic when present in the skin boils, throat lesions etc. as they survive, multiply and use RBCs from blood as important nutrient for themselves.

Lactobacilli from yoghurt , curd and buttermilk enter directly into our stomach and intestinal parts and further to GI tract. In the colon they would replace many harmful bacteria which are opportunist pathogen. Moreover LAB are  important as they can also promote the synthesis of B-complex vitamins. In fact you would realize that when doctor prescribes B-complex therapy after heavy antibiotic dose is for the same reason as antibiotics destroy the beneficial bacteria from our colon. So in conclusion I would say whether Lactobacilli are heamolytic or not should not be a cause of concern. Important test for LAB whether they belong to the homofermentor or heterofermentor category is this that it should be able to produce lactic acid from  the sugars such as glucose, sucrose etc. through their natural fermentation route.

In my opinion, , strains1 and 2 are alpha haemolytic, and 3, 4, 5 and 6 are beta-haemolytic.

culture No. 3 and 6 are beta heamolytic.

2, 4 and 5 are gamma heamolytic and

culture no. 1 is alpha heamolytic without any doubt.

In the first plate the second image is of beta hemolysis along with the first image of second plate. The third plate  is showing alpha hemolysis  and the rest should be either gamma or non hemolytic.

How an isolate can be haemolytic (gamma haemolysis) without haemolysis? What is then difference among non-heamolytic and haemolytic (gamma haemolysis) strain?

Dear Modestas,

True. It is a misnomer but widely accepted by the microbiologist worldover. So when you say gamma it means that there is no heamolysis.

It is simply A, B and C or 1, 2 and 3.

So it is alpha, beta and gamma, the category @ no. 3 and signifies that those bacterial cultures which belong to this third ( gamma) category do not produce any heamolysins and thus do not cause any heamolysis on blood agar.

Although pictures may be misleading, I would say that 1 and 3  are alpha and 2 is weak alpha. This is based on the green discoloration of the medium. In the other 3 I see no green discoloration so I would classify them as weak beta for  4 and 5 and beta for 6.  

Alpha haemolysis- Incomplete haemolysis produce greenish discoloration that surrounds the colony- Isolates 1 and 2

Beta haemolysis- Complete haemolysis- Isolates 3 and 6

Gamma haemolysis- No haemolysis- Isolates 4 and 5

All:

If you are going to use the definition of hemolysis for streptococci. It is not possible to determine the correct hemolysis from the pictures presented above.  Streptococcal hemolysis was definited in 1929 by J. H. Brown of Rockefeller Univeristy. He use pour plates where the streptococci formed colonies included in the the blood agar plates. He examine the edges of the subsurface colonies with a low power microscope.  those colonies with no red blood cells near the colony were termed Beta, colonies with some rbc destruction were termed alpha  and usually a greenish coloring developed because of the perocide production by the growth.  Non hemolytic colonies were surrounded by rbcs without any destruction.  Because most microbiologists do not prepare pour plates. another technique is now used. The blood agar plate is swabbed , then streaked with a wire (or plastic) loop to thin the growth and the wire swab is then stabbed into the agar plate in an area that has not been swabbed. After incubation the area surrounding the stab is examined with a low power microcope and the correct hemolysis can be easily determined by usBrowns definitions. .  You may find physical pictures of this at: http://phil.cdc.gov/phil/home.asp

Dear Richard R. Fachlam,

Thanks for your elaborate explanation on the subject matter.

Regards,

Dr. A. D. Padhye.

Respected all,

The best way to judge is to  have 24 h old culture ( when is that applicable ) and in any case observe isolated SINGLE colony  that represents pure culture isolates.  

 In this pictures, for my knowledge, types  of haemolysis are inconclusive.

Dear Violeta,

Your suggestion of going for single colony pure culture and that too 24 hrs old would definitely help a lot in getting correct information.

However out of 6 images provided at least 3 are quite clear as far as arriving at correct information regarding the type of heamolysis.

There are several conditions that will effect the expression of hemolytic activity of bacterial cultures, among them are the composition of the base media, the type of blood used in the agar plate (sheep blood is the standard but other bloods have been used) the percent of blood in the agar (5% is the standard), and the atmosphere of incubation, Streptococcal hemolysis was defined using anaerobic atmosphere with 5% horse blood. Fortunately I determined several years ago that rabbit, sheep, horse and human blood can be used to determine the correct hemolytic activity. Since none of these conditions are described in the original question. The correct answer to the question cannot be determined.

6 and 3 are clearly beta hemolytic, 4 and 5 are weakly beta hemolytic or no hemolytic, and 1 and 2 seems to me alfa hemolytic. Sorry I can't be more specific.

Alpha haemolysis- Isolates 1 and 2 Beta haemolysis- Isolates 3 and 6 Gamma haemolysis- Isolates 4 and 5

https://en.m.wikipedia.org/wiki/File:Streptococcal_hemolysis.jpg

I am not able to get access to images currently on the cellphone I am using right now.

But above reference would help you out with your query.

Complete destruction of RBCs is beta haemolysis. No haemolysis correspond to gamma and partial haemolysis i.e. partial destruction of RBCs from blood agar and resulting into green discoloration surrounding bacterial growth is alpha haemolysis.

Regards,