Infectious Agents Biology Flashcards Preview

D1S U1 Microbiology > Infectious Agents Biology > Flashcards

Flashcards in Infectious Agents Biology Deck (46):
1

60-80% of microbial infections are caused by _____

Biofilm bacteria

2

Oral biofilm bacteria are not randomly distributed, rather they ______ into clumps

Co-aggregate

3

Formation of Biofilms (steps):

1. Reversible adsorption of bacteria
2. Irreversible attachment "Sessile"
3. Multiply, microcolonies
4. Exopolymer production -> biofilm established
5. Incorporation of other bacteria/materials into biofilm

4

Bacteria attach to ______, NOT directly to surfaces

Conditioning film

5

Irreversible adsorption is caused by _____

Adhesion molecules

6

Bacterial needs that drive cooperative consortia formation:

Physical- bind to other species on surface
Nutritional- by products of metabolism, enzymes, proteins
Respiratory- anaerobes co-aggregate with facultative anaerobes

7

Mature biofilm is made up of:

75-95% extra cellular polymer (web)
5-25% bacteria

8

Release of bacteria from mature biofilm

Biofilm dispersal

9

Advantages (to microbes) of biofilm:

1. Protection
2. Rapid acquisition
3. Nutritional (pool resources)

10

Advantages (to host) of biofilm:

1. Prevent colonization of harmful organisms (competition)

11

Process of cell-cell communication by which bacteria monitor the density of members of their species, and other species, in an environment to synchronize behaviors

Quorum Sensing

12

Gram negative QS general mechanism components:

1. Signal molecule: autoinducer (AHL) made by LuxI
2. Receptor/Response regulator: LuxR

13

Gram+ general mechanism components:

1. Signal molecule: Oligopeptide
2. Receptor
3. Response regulator

14

3rd general mechanism of QS components:

1. Signaling molecule: AI-2
2. Made by G positive and negative species
3. Interspecies communication

15

Quorum Sensing can trigger:

1. Motility
2. Expression of virulence gens
3. Biofilm formation

16

You can either target the _____ or the _____ in QS to inhibit biofilm formation

Signaling molecule
Receptor

17

Gram- rods, strict anaerobes, normal residents of vertebrate intestinal and oral microbiomes, dominant genera, metabolize complex carbs

Bacteriodes

18

Bacteriodes have these two enzymes to detoxify and breakdown ROS

1. Superoxide Dismutase
2. Catalase

19

Why is B. Fragilis the predominant species in the intra-abdominal abscesses if it is not the most common Bacteriodes in the intestine normally?

1. It evades phagocytosis (anti-phagocytic capsule)
2. It tolerates the initial oxygenated environment of the peritoneal cavity
3. Thrives once the environment becomes anaerobic

20

How can abscesses harm the host?

1. Extends by tissue necrosis to nearby sites
2. Serve as reservoirs for bacteria to enter blood

21

How are abscesses diagnosed?

1. CAT scan
2. Culture abscess fluid (ID species)

22

How are abscesses treated?

Combined surgical/pharmacological approach

23

Characteristics of peritoneal cavity infections:

Biphasic (acute inflammation -> localized abscesses), few species predominate in abscesses

24

How can the peritoneal cavity become infected?

Spillage of intestinal material into cavity

25

Severe systemic illness characterized by hemodynamic derangement and multiple organ malfunction, brought about by interaction of microbial components with host macrophages. Begins with bacteremia (bacteria in blood).

Sepsis

26

High cardiac output yet low bp and inadequate perfusion of organs

Hemodynamic Derangement

27

In Sepsis, the host's own molecules cause the damage when ____ are recognized by ____.

PAMPs (Pathogen associated molecular patterns)

PRRs (Pattern recognition receptors)

28

Primary cytokine mediators of Sepsis?

IL-1
TNF-alpha

29

Effect of IL-1 and TNF-alpha on blood vessels:

1. Vasodilation: lowers bp
2. Vascular leakage: edema, lowers bp
3. Intravascular coagulation
4. Increased expression of neutrophil adhesion molecules: degranulation, tissue damage

30

Treatment for Sepsis:

1. Oxygen
2. IV fluids
3. Vasopressors
4. Antibiotics

31

General characteristics of _____: Helical shape, corkscrew-like movement, periplasmic flagella.

Treponemes (Spirochetes)

32

Modes of T. pallidum transmission:

1. Sexual
2. Transplacental

33

When T. Pallidum infects, it first enters ____ tissues for ______ replication. It is then carried through ____ channels to systemic circulation.

Subepithelial

Extracellular

Lymphatic

34

In primary syphilis, WBCs battle replicating spirochete and inoculation site, forming a lesion or a _____. This lesion increases risk of HIV infection.

Syphilitic Chancre

35

In secondary syphilis, bacteria replicate in _____. The body develops rashes on one or more places, even on ____. Because there are many variable symptoms during this stage, it is known as the _____. When symptoms resolve but bacterium persist, this is known as ____.

Lymph nodes, liver, joints, muscles, skin, mucous membranes

Palms and soles

Great Imitator

Latent Syphilis

36

____ syphilis is caused by the host's response to T. Pallidum antigens. Leads to the destruction of host tissues.

Tertiary

37

Tertiary syphilis lesions that destroy soft tissue, bone, organs.

Gummas

38

Tertiary syphilis -> neurosyphilis -> staggering (i.e. ___), dementia, and loss of motor function (i.e. ____)

Ataxic Gait

General Paresis

39

How is syphilis diagnosed?

Detecting of antibodies (treponeme)

40

How is syphillis treated?

Possible reason for treatment failure?

Penicillin

Inability of penicillin to penetrate CNS

41

What causes Lyme disease?

B. Burgdorferi (Borrelia Burgdorferi)

42

What triggers the normally dormant B. Burgdorferi?

When tick feeds on mammalian blood-> injected into mammal from tick salivary glands

43

B. Burgodorferi spread within is human is facilitated by it's ability to bind human _____.

Plasmin

44

Stages of Lyme disease:
1. Localized skin infection- forms a lesion known as _____.
2. Disseminated infection- damage mediated by host's response to antigens, involves _____
3. Symptoms include:

1. Erythema migrants
2. IL-1 and TNF-alpha
3. Arthritis, Lyme Encephalopathy (memory, Sleep, speech affected), Acrodermatitis Chronica Atrophicans (atrophy of skin)

45

Lyme Disease is diagnosed by:

Detecting antibodies (ELISAs, Western blots)

46

Treatment for Lyme Disease:

Penicillin not effective. Doxycycline or Amoxicillin better.