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Course Overview

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Theory Syllabus

Section I

• History, branches, scope, and importance of microbiology
• Prokaryotes vs Eukaryotes
• Bacterial ultra-structure and morphological classification
• Nutritional requirements, culture media, physical growth parameters
• Growth curve, isolation and preservation of pure cultures
• Cultivation of anaerobes
• Quantitative measurement of bacterial growth (total & viable count)

• Staining techniques: Simple, Gram's, Acid-fast
• Biochemical tests: IMViC
• Sterilization methods: physical, chemical, gaseous, radiation, mechanical
• Evaluation of sterilization efficiency
• Large-scale sterilization equipment
• Sterility indicators

• Morphology, classification, reproduction/replication, cultivation of Fungi and Viruses
• Classification and mode of action of disinfectants
• Factors influencing disinfection
• Antiseptics and their evaluation
• Evaluation of bactericidal & bacteriostatic activity

Section II

• Designing aseptic areas, laminar flow equipment
• Sources of contamination in aseptic areas and prevention methods
• Clean area classification
• Principles and methods of microbiological assay
• Standardization of antibiotics, vitamins, and amino acids
• Assessment of a new antibiotic

• Types of spoilage and factors affecting microbial spoilage of pharmaceutical products
• Sources and types of microbial contaminants
• Assessment of microbial contamination and spoilage
• Preservation using antimicrobial agents
• Evaluation of microbial stability of formulations

• Growth of animal cells in culture
• General procedure for cell culture
• Primary, established, and transformed cell cultures
• Applications of cell cultures in pharma industry and research
• Phase contrast, dark field, and electron microscopy

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Practical Experiments (15 total)

1. Study of microbiology equipment
2. Sterilization of glassware; preparation and sterilization of media
3. Sub-culturing of bacteria and fungi; nutrient stabs/slants; sterility testing of media
4. Motility by hanging drop; monochrome staining; metachromatic granule staining
5. Monochrome staining and metachromatic granule staining (extended)
6. Gram staining; negative staining
7. Morphology of spirochetes by negative staining; capsule staining
8. Isolation of pure cultures by multiple techniques
9. One-level microbiological assay of antibiotic
10. Two-level factorial assay method for antibiotic % potency
11. Sterility testing of absorbent cotton and gauze
12. Sterility testing of aqueous solution (without bactericide) and powder
13. Bacteriological analysis of water
14. Biochemical tests for starch and protein
15. Fermentation of carbohydrates

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Course Outcomes

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Reference Books

• Microbiology - Pelczar, Chan, Krieg (East-West Press)
• Pharmaceutical Microbiology - Hugo & Russel (Blackwell Scientific)
• Pharmaceutical Microbiology - N.K. Jain (Vallabh Prakashan)
• Industrial Microbiology - Prescott & Dunn (CBS)
• Text Book of Microbiology - Ananthnarayan (Orient-Longman)
• Cooper and Gunn's Tutorial Pharmacy - S.J. Carter (CBS)
• Indian Pharmacopoeia
• Fundamentals of Microbiology - Frobisher, Hinsdill et al. (Thomson Learning)

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Module 2: Staining, IMViC & Sterilization (8 hrs | 18%)

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PART A: Staining Techniques

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1. Simple (Monochrome) Staining

• Uses a single dye - e.g., methylene blue, crystal violet, safranin, or carbol-fuchsin.
• Stains all bacteria the same color - no differentiation between types.
• Purpose: observe cell morphology, size, and arrangement (cocci, rods, spirals).
• Quick and easy but gives no information about cell wall type.

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2. Gram's Staining (Differential Stain)

• Gram-positive bacteria → Purple (thick peptidoglycan wall retains the dye complex)
• Gram-negative bacteria → Red/Pink (thin peptidoglycan + outer membrane - dye complex washes out)

Important note: Gram-positive bacteria may fail to retain the stain if the organisms are old, dead, or damaged by antimicrobial agents. Always use young cultures for accurate results. - Sherris & Ryan's Medical Microbiology

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3. Acid-Fast Staining (Ziehl-Neelsen Stain)

• Acid-fast organisms (Mycobacteria) → Red/Bright pink (retain carbol-fuchsin)
• Non-acid-fast organisms → Blue (pick up methylene blue counterstain)

• Kinyoun stain - cold method (no heat needed, uses more concentrated carbol-fuchsin)
• Fluorochrome stain - uses auramine or auramine-rhodamine dye; acid-fast organisms fluoresce; more sensitive and used as method of choice in most labs
• Henry's Clinical Diagnosis and Management by Laboratory Methods

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PART B: Biochemical Tests - IMViC

I - Indole Test

• Principle: Tests whether the organism can break down tryptophan to produce indole using the enzyme tryptophanase.
• Reagent: Kovac's reagent (contains p-dimethylaminobenzaldehyde)
• Positive result: Cherry red ring at the top of the broth
• Negative result: Yellow/no color change
• E. coli = positive (+); Enterobacter = negative (-)

M - Methyl Red (MR) Test

• Principle: Tests whether the organism produces large amounts of mixed acids (lactic, acetic, formic acid) by fermenting glucose via the mixed acid fermentation pathway - drops the pH below 4.4.
• Reagent: Methyl red indicator added to MR-VP broth after 48 hours incubation
• Positive result: Red color (low pH, high acid)
• Negative result: Yellow color
• E. coli = positive (+); Enterobacter = negative (-)

Vi - Voges-Proskauer (VP) Test

• Principle: Tests whether the organism produces acetylmethylcarbinol (acetoin) as a fermentation product via the butylene glycol pathway.
• Reagents: Barritt's reagent (alpha-naphthol + KOH)
• Positive result: Red/pink color after 15-30 minutes (acetoin oxidized to diacetyl)
• Negative result: No color change (copper/yellow)
• Enterobacter = positive (+); E. coli = negative (-)

C - Citrate Utilization Test

• Principle: Tests whether the organism can use citrate as its sole carbon source.
• Medium: Simmons' citrate agar (contains bromothymol blue as indicator)
• Positive result: Growth + bright blue color (alkaline pH due to NH3 production)
• Negative result: No growth, medium stays green
• Enterobacter = positive (+); E. coli = negative (-)

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PART C: Sterilization Methods

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1. Physical Methods

A. Moist Heat (Steam)

• Boiling (100°C): Kills vegetative bacteria but NOT spores. Not considered true sterilization.
• Autoclave (Steam under pressure) - Gold standard:
  • Uses saturated steam at 121°C, 15 psi pressure, for 15 minutes
  • "Flash" autoclaves used in operating rooms use 134°C for 3 minutes
  • Mechanism: steam denatures microbial proteins irreversibly
  • Kills all organisms including spores
  • Must ensure no air pockets - air prevents steam penetration
  • Sterility indicator: Spores of Geobacillus stearothermophilus (most resistant to moist heat)
  • Sherris & Ryan's Medical Microbiology
• Pasteurization (55-75°C): Kills vegetative bacteria, spores survive. Used for milk and beverages.

B. Dry Heat

• Hot air oven: 160°C for 2 hours (or 170°C for 1 hour)
• Mechanism: oxidation and protein denaturation
• Less efficient than moist heat - requires higher temperature and longer time
• Used for: glassware, oils, waxes, powders that cannot be sterilized in an autoclave (immiscible with water)
• Sterility indicator: Spores of Bacillus atrophaeus (formerly B. subtilis)
• Incineration: Immediate, complete destruction by flame - used for wire loops in labs, contaminated disposables

C. Radiation

• Ultraviolet (UV) light:
  • Absorbed by DNA, causes formation of thymine dimers → DNA damage
  • Non-ionizing radiation; poor penetration (cannot pass through glass, plastic, or water)
  • Used for: surface sterilization, disinfecting air in hospital rooms, laminar flow hoods
  • Merits: no chemical residue; Demerits: poor penetration, not sporicidal
• Ionizing radiation (Gamma rays, Cathode rays):
  • Causes direct DNA damage + generates free radicals and H₂O₂ from water
  • Deep penetration; can sterilize packaged material
  • Used for: disposable surgical supplies (gloves, syringes, catheters), foodstuffs
  • Sterility indicator: Bacillus pumilus spores
  • Sherris & Ryan's Medical Microbiology

D. Filtration

• Removes microorganisms by physical size exclusion - does NOT kill them
• Membrane filters with pore size 0.2 µm - removes bacteria effectively
• Used for: heat-labile fluids (serum, certain vaccines, ophthalmic solutions, IV fluids)
• Cannot remove viruses (too small)
• Types: membrane filters (nitrocellulose, PVDF), HEPA filters (for air in aseptic areas)

E. Mechanical Methods

• Centrifugation - sediments microorganisms from liquid
• HEPA filtration - removes 99.97% of particles ≥0.3 µm from air; used in laminar flow hoods and cleanrooms

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2. Chemical Methods

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3. Gaseous Methods

• Ethylene oxide (EO):
  • Alkylating agent - reacts with DNA and proteins, killing all microorganisms including spores
  • Used for: heat-sensitive and moisture-sensitive materials (plastic devices, catheters, some electronics)
  • Merits: penetrates packaging, effective at low temperatures
  • Demerits: potentially explosive, toxic, requires long aeration time after sterilization to remove residues
  • Sterility indicator: B. atrophaeus spores
• Formaldehyde gas: used for fumigation of rooms/cabinets
• Hydrogen peroxide vapor (VHP): used for room decontamination in pharma

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4. Evaluation of Sterilization Efficiency

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Comparison Table: Key Sterilization Methods

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