Systemic Bacteriology Notes
Subject Overview
Systemic Bacteriology moves from general microbiology into the identification of specific pathogens — bacterial culture procedures and staining techniques (Gram, Ziehl-Neelsen, Albert's, capsule stain), the biochemical tests used to identify bacteria (catalase, coagulase, indole, MR, VP, urease, citrate, oxidase, TSI and more), and the morphological, cultural and biochemical characteristics, pathogenesis and laboratory diagnosis of major bacterial genera from Staphylococcus and Streptococcus through the Enterobacteriaceae, Mycobacterium, spirochetes and Mycoplasma. A 4-credit core theory paper.
Subject at a glance
3
Units
39
Topics
4
Credits
3
Infographics
Unit-wise Syllabus
3 units — open any unit for detailed topic-wise notes, diagrams and important exam questions
- Instruments for seeding culture media
- culture procedures
- staining techniques — principle
- procedure
- significance and interpretation of simple staining
- Gram stain
- Ziehl-Neelsen staining
- Albert's stain and capsule staining
- 1Crystal violet
1 min: primary stain
- 2Gram's iodine
1 min: mordant
- 3Decolourise
Acetone or alcohol, a few seconds
- 4Safranin
Counterstain
- 5Read
Gram-positive purple, Gram-negative pink
Study guide
This unit covers seeding culture media, culture procedures and key staining techniques: simple staining, Gram stain, Ziehl-Neelsen, Albert's and capsule staining, with their principles and interpretation. Learn the Gram stain steps and what Gram-positive and Gram-negative colours mean.
- Principle
- procedure and interpretation of catalase
- coagulase
- indole
- methyl red
- Voges-Proskauer
- urease
- citrate
- oxidase
- TSI
- nitrate reduction
- carbohydrate fermentation
- Hugh and Leifson
- bile solubility
- H2S production and motility tests
Catalase
Bubbles with H2O2
Staphylococcus (Streptococcus is negative)
Coagulase
Plasma clots
Staphylococcus aureus
Indole
Red ring with Kovac's reagent
E. coli
Urease
Pink colour
Proteus
Oxidase
Purple colour
Pseudomonas, Vibrio
Study guide
You study the principle, procedure and interpretation of biochemical tests for identifying bacteria: catalase, coagulase, indole, methyl red, Voges-Proskauer, urease, citrate, oxidase, TSI, nitrate reduction, carbohydrate fermentation, Hugh-Leifson, bile solubility, H2S production and motility. Prepare a table of expected results for common organisms.
- Morphological
- cultural and biochemical characteristics
- pathogenesis and laboratory diagnosis of Staphylococcus
- Streptococcus
- Pneumococcus
- Neisseria gonorrhoeae and N. meningitidis
- Haemophilus
- Corynebacterium
- Enterobacteriaceae (E. coli, Klebsiella, Proteus, Salmonella, Shigella)
- Vibrio
- Clostridium
- Mycobacterium tuberculosis complex/atypical mycobacteria/M. leprae
- spirochetes (Treponema, Borrelia, Leptospira)
- Bordetella
- Brucella
- Mycoplasma and Ureaplasma
Gram-positive cocci
Staphylococcus, Streptococcus, Pneumococcus
Gram-negative cocci
Neisseria
Gram-positive bacilli
Corynebacterium, Clostridium
Gram-negative bacilli
E. coli, Klebsiella, Salmonella, Vibrio
Acid-fast bacilli
Mycobacterium tuberculosis, M. leprae
Spirochaetes
Treponema, Leptospira, Borrelia
Study guide
You study the characteristics, pathogenesis and laboratory diagnosis of the major bacterial pathogens, including Staphylococcus, Streptococcus, Pneumococcus, Neisseria, Haemophilus, Corynebacterium, the Enterobacteriaceae, Vibrio, Clostridium, Mycobacteria, spirochetes, Bordetella, Brucella and Mycoplasma. For each organism, learn the disease, specimen, key tests and identifying features.
Why Systemic Bacteriology Matters
Identifying bacteria quickly and correctly guides patient treatment, and these techniques are the daily work of a clinical microbiology technologist.
How to Prepare for Systemic Bacteriology
- Make one summary table of organism, disease, specimen, stain and key biochemical results.
- Practise the Gram stain and acid-fast stain on known smears.
- Revise biochemical tests as a flowchart for identifying Gram-negative rods.
Systemic Bacteriology: Frequently Asked Questions
Why is Gram staining important?
It is a rapid first test that separates bacteria into Gram-positive and Gram-negative groups, guiding further tests and early treatment.
What does the catalase test show?
It tests for the enzyme catalase, which separates Staphylococcus (positive) from Streptococcus (negative).