I: Bacteriology

Taxonomy

classification of organisms into categories based on genotypic and phenotypic characteristics

1. Domain

2. Kingdom

3. Division

4. Class

5. Order

6. Family

7. Genus

8. Species

Hierarchy of classification

Subspecies

same species but differ phenotypically

Biotype

same species, same genetic makeup, but different physiologic characteristics

Serovar

same species but differ serologically

Strain

same species, but different subtype or genetic variant

1. Subspecies

2. Biotype

3. Serovar

4. Strain

What are under species

eukaryotic

cells of human & plant

Prokaryotic

cells of bacteria & fungi

T

Prokaryotic (t/f)

they have no organelles; no membrane-enclosed structure

F

do not have nucleus

Prokaryotic (t/f)

have nucleus

T

Prokaryotic (t/f)

have 70s ribosomes & are haploid with a single chromosome

mycoplasma & ureaplasma

Prokaryotic

cell wall: with peptidoglycan expect

carbohydrate & sterol

Prokaryotic

cytoplasmic membrane: fluid phospholipid bilayer with

cytoplasmic membrane

Prokaryotic

site of energy production

free ribosomes

Prokaryotic

site of protein synthesis

F

unicellular

Prokaryotic (t/f)

multicellular

F

unicellular; contains DNA & RNA

Prokaryotic (t/f)

unicellular; contains DNA only

0.2 - 5.0 µm

Prokaryotic

average size

Mycoplasma spp.

Prokaryotic

smallest

Bacillus spp.

Prokaryotic

largest

binary fission

Prokaryotic multiplies by

1. Bacilli

2. Comma

3. Cocci

4. Spiral

4 Morphology of Prokaryotic

1. In clusters

2. In chains

3. In pairs

4. In tetrads

Microscopic Morphology of Bacteria

Cocci

cocci: in clusters

identify

cocci: in chains

identify

cocci: in pairs

identify

cocci: in tetrd

identify

bacilli

rod-shaped

1. Coccobacilli

2. Bacilii of various sizes

3. Fusiform bacilli

4. Palisading

Microscopic Morphology of Bacteria

Bacilli

bacilli: coccobacilli (slightly curved edges)

identify

bacilli: bacilli of various sizes

identify

bacilli: fusiform bacilli (sickle shaped)

identify

palisading

identify

Spirochetes

spiral

Biofilm

property of bacteria to attach to a solid surface

Pathogenicity

the ability of a microbe to produce disease in a susceptible individual

Virulence

relative ability of microorganisms to cause disease or the degree of pathogenicity; usually measured by the number of microorganisms necessary to cause infection in the host

adherence factors

Virulence

_- pili/fimbriae

Anti-phagocytic factors

Virulence

_ - capsule and self-component of cell wall

Enzymes

Virulence

_ - i.e. Coagulase: S. aureus; Fibrinolysin- sp

0.20 - 2.0 um

Size of the cell of prokaryotes

F

usually present

Cell wall of prokaryotes is usually absent (t/f)

T

Nucleus of prokaryotes (t/f)

absence of nuclear membrane or nucleoli

in the nucleoid, at the mesosomes

genome location of prokaryotes

without histones

Chromosomes of prokaryotes

Single, singular chromosomes; _

Absent

membrane-bounded organelles of prokaryotes

70s

ribosomes of prokaryotes

Present; smaller size -

T

PRESENT

Pili and Fimbriae of prokaryotes is Present (t/f)

10-100um

Size of the cell of eukaryotes

T

Cell wall of of eukaryotes is usually absent, except for fungi (t/f)

T

Nucleus of eukaryotes (t/f)

True nucles of nuclear membrane or nucleoli

in the nucleus

genome location of eukaryotes

with histones

Chromosomes of eukaryotes

Multiple liner chromosomes; _

PRESENT

membrane-bounded organelles of eukaryotes is present (t/f)

80s

ribosomes of eukaryotes

Present; larger size -

Absent

Pili & fimbriae of eukaryotes

gram +

Producer of Exotoxin

released by all major gram

living bacteria

DOES NOT require cell death for release

Manner of excretion of Exotoxin

Exotoxin is excreted by ___________ and it __________ ____________; the metabolic product of bacteria

F

mainly protein in nature

Composition of Exotoxin (t/f)

polysaccharide and lipids

High

Toxicity of Exotoxin

unstable at 60

Stability to heating of Exotoxin

Exotoxin

Stimulates antitoxin production: Yes (can be converted into toxoid; easily neutralized by anti- toxin)

Exotoxin

Specificity

Binds to specific receptors

Exotoxin

Synthesis: Controlled by extrachromosomal gene

Local

Composition of Exotoxin

“________”- one area not associated with fever

gram -

Producer of Endotoxin

usually produced by gram

cell death

Manner of excretion of Endotoxin

It requires ________________ for release (cell wall disintegration)

F

polysaccharide and lipids

Composition of Endotoxin (t/f)

mainly protein in nature

Systemic

Composition of Endotoxin

“___________”- all over the body

low

Toxicity of Endotoxin

Stable

Stability to heating of Endotoxin

Endtoxin

Stimulates antitoxin production: No (cannot be converted into toxoid, not easily neutralized by anti- toxin)

Endotoxin

Specificity

Specific receptors not found on cells

Endotoxin

Synthesis directed by chromosomal genes (inside the cell)

1. Cell Envelope

   • Capsule

   • Cell wall

   • Plasma membrane

2. Pili / Fimbriae

3. Endospores

4. Flagella

5. Metachromatic Granules / Cytoplasmic Granules/Inclusion Bodies

6. Ribosomes

7. Mesosomes

8. Cytosol

9. Nucleoid

Bacterial Cell Structure

Cell envelope

Composed of layers (capsule, cell wall, cell membrane) that surround the bacterium

T

NOT ALL organisms have a cell wall, responsible for mucoid colonies (t/f)

polysaccharide / polypeptide

Cell envelope

Capsule is usually made of

T

Cell envelope (t/f)

Capsule prevents phagocytosis and is considered a virulence factor

Quellung reaction

Cell envelope

Capsule is antigenic; based on serotyping by

Neufeld-Quellung capsular Ag

Cell envelope

Capsule

what serologic test is (+) capsular swelling due to Ag-Ab complex

Somatic O Ag

Cell envelope

Capsule

_: heat stable

1. Vi Ag (salmonella)

2. K Ag (E.coli)

Cell envelope

Capsule

_: heat labile

animal tissues & fluids

Cell envelope

Capsule

Demonstration:

milk & serum

Cell envelope

Capsule

Media containing

mucoid & slimy

Cell envelope

Capsule

Colonies often

1. MUIR

2. ANTHONY’S

3. TYLER

4. HISS

5. WELCH’S

6. GRIN’S

Cell envelope

Capsule

Stains are

Cell wall

defines the shape of the bacteria

Cell wall

point of anchorage for flagella, site of attachment, and antibiotic action

M Protein of Streptococcus pyogenes

Cell wall

Pathogenicity:

_ - major virulence factor and prevents phagocytosis

Mycolic acid

responsible for acid fastness of Mycobacterium spp. and prevents digestion during phagocytosis

Poly-d-glutamic acid

Cell wall

Pathogenicity:

_- Bacillus spp.

Chitin

Cell wall

Pathogenicity:

_- fungi

L-forms

Cell wall

Pathogenicity:

_ are organisms that have temporarily lost their cell wall as a result of environmental condition

N-acetyl-d-glucosamine (NAG) & N-acetyl-d-muramic acid (NAM)

Cell wall

Peptidoglycan (murein layer) consists of glycan chains of alternating - and

-

Mycoplasma & Ureaplasma

Cell wall

- lack cell wall, and only contains sterol; making them pleomorphic and sensitive to osmotic pressure

sterol

Cell wall

Mycoplasma & Ureaplasma lack cell wall, and only contains _ ; making them pleomorphic and sensitive to osmotic pressure

F

Gram-positive and gram-negative cells can lose their cell walls and grow as L- forms in media supplemented with serum or sugar to prevent osmotic rupture of the cell membrane

Cell wall (t/f)

Gram-positive and gram-negative cells cannot their cell walls and grow as L- forms in media supplemented with serum or sugar to prevent osmotic rupture of the cell membrane