Bacteriology

Front 1

Real pathogens

Back 1

i. Identifiable and treatable

Front 2

Viral infections

Back 2

i. Usually predispose to serious bacterial infections

Front 3

Bacterial pathogenesis

Back 3

i. Better defined than viral pathogenesis

Front 4

Bacterial pathogens

Back 4

i. Do not respect anatomical boundaries

Front 5

Bacteria

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a. Prokaryotes
b. No cytoplasmic organelle other than ribosomes
c. Genetic information is stored in circular chromosome
d. Genetic information can also be extra-chromosomal (plasmids)

Front 6

Bacterial cell wall

Back 6

a. Excellent antibacterial target
b. Gram + or -

Front 7

Gram positive cell wall

Back 7

i. Thick (20-80 nm)
ii. External to cell membrane
a. Thick PG layer with TA and LTA

Front 8

Gram negative cell wall

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i. Thin (5-10 nm)
ii. Between inner and outer membrane

Front 9

Gram stain

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a. Separates gram positive and gram negative bacteria
b. Purple is positive

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Aerobic

Back 10

a. Grows in presence of oxygen

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Facultative

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a. Can grow in presence or absence of oxygen

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TA and LTA

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i. Important for viability, virulence, and serotyping
ii. Promote attachment to mammalian cells
iii. Low endotoxin activity

Front 13

Bacterial ribosomes

Back 13

a. Protein synthesis inhibitors serve better in toxigenic diseases than cell wall inhibitors
b. 50s+30s=70S

Front 14

50s subunit

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a. 5S rRNA
b. 31 proteins

Front 15

30s subunit

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a. 21 proteins
b. 16S RNA

Front 16

Encapsulated bacteria

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a. Loose polysaccharide layer
b. Unnecessary for growth but important for virulence
c. Promotes adherence, anti-phagocytic, poor antigen

Front 17

Gram positive that produce endospores

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a. Produced under unfavorable conditions
b. Non-replicating entity with thick coat
c. Contain DNA and other essential substances
d. Toughest life form, can germinate back into vegetative cells

Front 18

Bacterial flagella

Back 18

a. H-antigens
b. Propellers that confer motility towards food and away from poisons
c. Assist in bacterial attachment to human cells
d. Mono-, lopho-, amphi-, peritrichous

Front 19

Virulence factor

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a. Factors or features that assist in bacterial attachment to human cells

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Periplasmic space

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a. Only seen in gram (-) bacteria

Front 21

Bacgeria fimbriae

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a. Pilli
b. F-antigens
c. Hair-like projections, thinner, shorter than flagella
d. Originate in plasma membrane and protrude through cell wall
e. Can act as adhesins and are major virulence factors

Front 22

Gram negative bacteria outer membrane

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a. Permeability barrier for large molecules (lysozyme, antimicrobials)
b. Protects from adverse conditions (GI tract of host)
c. Normal inner leaflet

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Outer leaflet of gram-negative bacteria

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i. Primarily LPS

Front 24

Bacterial LPS

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1. Characteristic of gram (-) bacteria
2. Integral part of the outer membrane
3. Released after cell death
4. When host senses LPS, it turns on every defense at its disposal

Front 25

Acid-fast and partially acid-fast bacteria

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a. PG layer is surrounded by a wax-like lipid coat
b. Responsible for virulence an dis antiphagocytic

Front 26

What determines acid-fastness?

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i. C-chain length of mycolic acids

Front 27

Lipid coat in acid-fast bacteria contains...

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i. Mycolic acid
ii. Cord factor
iii. Wax D
iv. Sulfolipids

Front 28

Lag phase

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i. Bacteria start to grow

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Exponential phase

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i. Population doubles every 20 minutes

Front 30

Stationary phase

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i. Growth stops

Front 31

Death phase

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i. Bacteria die faster than they multiply

Front 32

Esophagus and stomach flora

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i. Lactobacilli
1. <10%

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Lactobacilli/streptococci in small bowel flora

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1. <10%
2. 10^3-10^5/g

Front 34

Enterobacgeria, bacteriodes spp in small bowel flora

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1. <10%
2. 10^5-10^8/g

Front 35

100% of large intestine flora

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1. Bacteriodes spp
2. Fusobacterium spp
3. E. faecalis
4. E. coli

Front 36

10-25% of large intestine flora

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1. Lactobacilli
2. S. aureus
3. Clostridium spp.

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25-75% of large intestine flora

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1. Enterobacteria
2. Klebsiella spp
3. Eubacteria
4. Bifidobacteria

Front 38

<10% of large intestine flora

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1. Streptococci
2. Pseudomonas
3. Salmonella

Front 39

100% of fecal material flora

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1. Bacteriodes spp.
2. Bifidobacteria
3. Eubacteria

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<10% of fecal flora

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1. Coliforms
2. E. Faecalis

Front 41

Low flora sites

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i. Bladder
ii. Uterus
iii. Part of digestive and respiratory tracts

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Sterile sites (w/o flora)

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i. Blood, lymph
ii. CSF
iii. Synovial fluid
iv. Sub-epidermal tissues

Front 43

Obligatory steps for infections

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a. Acquisitions/colonization (epidemiology)
b. Immune evasion/infection
c. Replication/proliferation
d. Dissemination and disease
e. Treatment (identification)

Front 44

Virulence phases

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a. Immune evasion/infection
b. Replication/proliferation
c. Dissemination and disease

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Transmission of bacterial pathogens

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a. Bacterial shedding
b. Coughing, sneezing, talking
c. Talking specially when consonant f, p, t, and s are used
d. Stability in the environment
e. Living conditions, age group, and immunocompetence

Front 46

Strain and inoculum size in infection

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i. <200 Shigella for shigellosis (human to human transmission)
ii. >100m for GI infection by Vibrio (no human to human transmission)

Front 47

Length of bacterial presence in infection

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i. Longer in the body=greater chance to cause disease

Front 48

Host factors in infection

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i. >10^6 Salmonella for gastroenteritis in healthy
ii. <10^3 in those with neutral gastric pH

Front 49

Bacterial infections-- surface v. systemic

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a. Infection originates on dry or less moist skin surface
b. Less likely to spread within the body but contagious
c. If the infection originates in UGT< GI, or LRT
d. Easy systemic spread