Primary Purpose of Bacterial Culture Media

In this blog post, I have listed the commonly used culture media in the Bacteriology laboratory and their primary purpose.  There are still lots of culture media not mentioned in this post which may or may not be the modifications of the media mentioned below.

Different types of Bacteriological culture media used in the microbiology lab

1. Bile esculin agar (BEA):  It is used for the differential isolation and presumptive identification of group D streptococci and enterococci.
2. Bile esculin azide agar with vancomycin: Selective and differential culture media commonly used for the cultivation of vancomycin-resistant enterococci from clinical and surveillance specimens.
3. Blood Agar:  Blood agar is used for the cultivation of fastidious microorganisms. It is a differential medium that helps to classify/identify the bacteria on the basis of types of hemolysis (alpha, beta or no hemolysis) present.
   

   Blood agar showing β-hemolysis
4. Bordet-Gengou agar: It is used for the isolation of  Bordetella pertussis, the causative agent of pertussis or whooping cough.
5. Buffered Charcoal-yeast extract agar (BCYE): Enrichment culture media for Legionella spp, the causative agent of Legionnaires’ disease, also known as legionellosis.
6. Buffered Charcoal-yeast extract agar with antibiotics: This culture media is used for the enrichment and selection of Legionella spp
   
7. Campy-blood agar (Campylobacter Blood Agar): Selective culture media for Campylobacter spp. Campylobacter is a leading cause of bacterial foodborne diarrheal disease worldwide
8. Campylobacter thioglycollate broth:  Selective holding medium for recovery of Campylobacter spp.
9. Chocolate agar: Cultivation of Haemophilus spp and pathogenic Neisseria spp.
10. Columbia colistin-nalidixic acid (CNA) agar: Columbia Agar with colistin and nalidixic acid (CNA) is a selective medium for gram-positive organisms. The antimicrobials colistin and nalidixic acid inhibit gram-negative organisms. CNA agar is used for the selective isolation of Gram-positive cocci such as staphylococci and streptococci.
11. Cystine-tellurite blood agar: Used for the isolation of Corynebacterium diphtheriae. 
12. Eosin Methylene Blue (EMB) Agar (Levine): Isolation and differentiation of lactose fermenting and non-lactose fermenting gram-negative enteric bacilli.
13. Gram-negative broth (GN): Selective (enrichment) liquid medium for enteric pathogens.
14. Hektoen enteric (HE) agar: Differential, selective culture medium used for the isolation and differentiation of Salmonella and Shigella spp from other gram-negative enteric bacilli.
    

    LF and NLF colonies in MacConkey Agar
15. MacConkey agar:  It is commonly used for the isolation and differentiation of lactose fermenting and non-lactose fermenting gram-negative enteric bacilli.
16. MacConkey Sorbitol Agar (It is a modification of MacConkey agar in which lactose has been replaced with d-sorbitol as the primary carbohydrate): It is used for the selection and differentiation of E.coli O157: H7 from a stool specimen
17. Mannitol Salt Agar (MSA): Primary purpose of MSA is the selective isolation of Staphylococci and differentiation of Staphylococcus aureus from coagulase-negative staphylococci (CONS).
18. New York City (NYC) Agar: It is a selective culture media for Neisseria gonorrhoeae.
19. Phenylethyl alcohol (PEA) agar: Selective isolation of gram-positive and anaerobic gram-negative bacilli
20. Salmonella-Shigella agar: Selective for the isolation of Salmonella and Shigella spp.
21. Selenite broth: Used for the enrichment and isolation of Salmonella spp.
22. Tetrathionate broth: Selective for the isolation of Salmonella and Shigella spp.
23. Thayer-Martin Agar: Selective culture medium for Neisseria gonorrhoeae and Neisseria meningitidis.
24. Thioglycollate broth:  It supports the growth of anaerobes, aerobes, microaerophile, and fastidious microorganisms.
25. Thiosulfate Citrate Bile Salt (TCBS) Agar: It is a selective and differential culture medium for the isolation of Vibrio e.g. Vibrio cholerae, the leading cause of cholera worldwide.
26. Trypticase Soy broth (TSB): It is an enrichment broth used for subculturing various bacteria from primary agar plates.
27. Xylose Lysine Desoxycholate (XLD) agar: XLD agar is used for the isolation and differentiation of Salmonella and Shigella spp from other gram-negative enteric bacilli.

Acharya Tankeshwar

Hello, thank you for visiting my blog. I am Tankeshwar Acharya. Blogging is my passion. As an asst. professor, I am teaching microbiology and immunology to medical and nursing students at PAHS, Nepal. I have been working as a microbiologist at Patan hospital for more than 10 years.

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