EXERCISE 2: BACTERIAL MORPHOLOGY AND TYPES

Cocci

Bacilli

Spiral

The three basic morphology of bacteria

Binary fission

Bacteria multiply through this. An organism duplicates its genetic material, or Deoxyriboneuleic Acid (DNA), and then divides into two parts (cytokinesis), with each new organism receiving one copy of DNA

Micrometers (μm)

This is the measurement of Bacteria

Cocci

Spheres

• Staphylococci

• Streptococci

• Diplococci

These are the three types of Cocci

0.4-2 µm

Measurement of cocci

Staphylococci

These are clusters or grape-like masses

Streptococci

Cocci that are in chains

Diplococci

Cocci that divide to form pairs

Staphylococcus Aureus

Representative microorganism of Staphylococci

(+) gram stain

Type of stain used in Staphylococcus Aureus

Streptococcus pyogenes

Representative microorganism of Streptococci

(+) gram stain

Type of stain used in Streptococcus pyogenes

Streptococcus pneumoniae

Representative microorganism of Diplococci

(+) gram stain

Type of stain used in Streptococcus pneumoniae

Bacilli

Rods

(0.2-4 µm x

0.5-20 µm)

[width x length]

Measurement of Bacilli

• Streptobacilli

• Diplobacilli (Snapping and Slipping)

• Coccobacilli

• Vibrio

Types of Bacilli

Diplobacilli

Bacilli that are formed in pairs

Bacillus subtilis

Representative microorganism of Streptobacilli

(+0) gram stain

Types of stain used in Bacillus subtilis

Diplobacilli

Types of bacilli that form in pairs

Snapping and Slipping

2 Types of Diplobacilli

Mycobacterium tuberculosis

Representative microorganism of Diplobacilli (both Snapping and Slipping)

Snapping

Type of Diplobacilli wherein 2 bacilli forms a V-shape

Slipping

Type of Diplobacilli wherein 2 bacilli are arranged side by side

Coccobacilli

Types of bacilli that is short, thick, and oval-shaped

Escherichia Coli

Representative microorganism of Coccobacilli

Acid fast stain

Type of stain used in Mycobacterium tuberculosis

(-) gram stain

Types of stain used in Escherichia Coli

Vibrio

Type of bacilli that is comma-shaped

Vibrio cholerae

Representative microorganism of Vibrio

(-) gram stain

Type of stain used in Vibrio cholerae

Spiral

Spirllum (Spiral)

Campylobacter jejuni

Representative microorganism used in Spiral

Staphylococcus Aureus

• Size: 0.5-1.5 µm

• Shape: Spherical

• Color: Purple

• Arrangement: Grape-like

Streptococcus Pyogenes

• Size: 0.6-1.0 µm

• Shape: round-to-ovoid coccus

• Color: purple

• Arrangement: in chains

Streptococcus pneumoniae

• Size: 0.5-1.25 µm

• Shape: round-to-ovoid coccus

• Color: purple

• Arrangement: in pairs

Bacillus subtilis

• Size: 4-10 µm long and 0.25 µm in diameter

• Shape: rod-shaped

• Color: purple

• Arrangement: small clumps

Mycobacterium tuberculosis

• Size: 2-4 µm long and 0.2-0.5 µm in diameter

• Shape: rod-shaped

• Color: red

• Arrangement: heaps of small rods

Escherichia coli

• Size: 1-2 µm long and 0.5 µm in radius

• Shape: rod shaped

• Color: pink

• Arrangement: singly or in pairs

Vibrio cholerae

• Size: 1-3 µm long and 0.5-0.8 µm in diameter

• Shape: comma

• Color: pink

• Arrangement: flagellum at one cell pole as well as pili

Campylobacter jejuni

• Size: 4 µm long and 0.2-0.5 µm width

• Shape: S-shaped, bird in flight

• Color: pink

• Arrangement: single flagellum at one or both poles

• Positive gram stain

• Negative gram stain

• Acid fast stain

These are the three Stain characteristics

Blue/Purple

Color that indicates a positive gram stain

Thick cell wall of the bacteria

What causes the blue/purple color in a positive gram stain?

Red

Color that indicates a negative gram stain

Thin cell wall of the bacteria

What causes the red color in a negative gram stain

Also Red

Color that indicates an Acid fast stain

Waxy cell wall of the bacteria

What causes the red color in Acid fast stain

Variations of cell walls of the bacteria

The different colors of the bacteria in this exercise is due to what