| Organism | Medium | Key fact |
|---|
| Haemophilus influenzae | Chocolate agar | Requires X + V factors |
| Neisseria gonorrhoeae | Thayer–Martin | Selective medium |
| Bordetella pertussis | Bordet–Gengou or Regan–Lowe | Whooping cough |
| Corynebacterium diphtheriae | Tellurite agar; Löffler medium | Diphtheria |
| Mycobacterium tuberculosis | Löwenstein–Jensen; Middlebrook | Slow-growing acid-fast bacillus |
| Mycoplasma pneumoniae | Eaton agar | Requires cholesterol |
| Legionella pneumophila | Buffered charcoal yeast extract (BCYE) | Requires cysteine and iron |
| E. coli | MacConkey; EMB | Pink on MacConkey; metallic green sheen on EMB |
| Salmonella | XLD, Hektoen enteric or other selective enteric media | Often H₂S-positive |
| Shigella | XLD, Hektoen enteric or other selective enteric media | Usually H₂S-negative |
| Vibrio cholerae | TCBS agar | Yellow colonies from sucrose fermentation |
| Staphylococcus aureus | Mannitol salt agar | Often yellow due to mannitol fermentation |
| Streptococcus pneumoniae | Blood agar | Alpha-hemolytic; optochin-sensitive |
| Streptococcus pyogenes | Blood agar | Beta-hemolytic; Group A |
| Clostridium species | Anaerobic media | Grow under anaerobic conditions |
| Candida species | Sabouraud agar | Yeast culture |
Correction worth remembering: Legionella is associated with BCYE agar, not ordinary blood agar as its principal specialized culture medium.
| Medium | Appearance | Interpretation |
|---|
| Blood agar | Clear zone | Beta-hemolysis |
| Blood agar | Greenish zone | Alpha-hemolysis |
| Blood agar | No hemolysis | Gamma-hemolysis |
| MacConkey | Pink colonies | Lactose fermentation |
| MacConkey | Colorless colonies | No lactose fermentation |
| EMB | Green metallic sheen | Classically E. coli |
| Mannitol salt agar | Yellow medium/colonies | Mannitol fermentation, commonly S. aureus |
| TCBS | Yellow colonies | Sucrose-fermenting V. cholerae |
| TCBS | Green colonies | Often V. parahaemolyticus |
| Tellurite medium | Dark colonies | May indicate C. diphtheriae |
Culture media grow organisms; stains help visualize or identify them microscopically.
| Stain | Main use | High-yield organism |
|---|
| Gram stain | Gram-positive versus Gram-negative bacteria | Initial bacterial classification |
| Ziehl–Neelsen | Acid-fast organisms | Mycobacterium tuberculosis |
| Giemsa | Blood parasites and selected intracellular organisms | Plasmodium |
| India ink | Demonstrates capsule against a dark background | Cryptococcus neoformans |
| PAS | Carbohydrate-rich structures | Whipple disease tissue findings |
| Silver stain | Selected bacteria, fungi and tissue organisms | Pneumocystis, Legionella in appropriate methods |
| Fluorescent antibody | Detects selected microbial antigens | FTA-ABS for syphilis testing |
