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Microbiology > Unit 9 > Flashcards

Unit 9 Flashcards

1
Q

Symbiotic association

A

Organisms live in close nutritional relationships; required by one or both members

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2
Q

Non symbiotic association

A

Organisms whose relationship is not required for survival

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3
Q

Synergism

A

Members cooperate and share nutrients

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4
Q

Antagonism

A

One or several members are inhibited or destroyed by others

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5
Q

Pathogen

A

Microbe whose relationship with its host is parasitic and results in an infection

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6
Q

Non pathogenic microorganisms

A

Commensals or mutualists

Saprobes/saprophytes ( gets nutrients from dead remains of other organisms)

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7
Q

Types of pathogenic microorganisms

A

Primary/ True pathogens

Opportunistic pathogens

Facultative pathogens

Emerging pathogens

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8
Q

Primary pathogen

A

Capable of causing disease in healthy person with normal immune defenses

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9
Q

Opportunistic pathogens

A

Cause disease when host’s defenses are compromised or when they become established in a part of the body that is not natural to them

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10
Q

Facultative pathogens

A

organisms for which the host is only one of the niches they can exploit to reproduce.

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11
Q

Emerging

A

Newly identified

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12
Q

Pathogenicity

A

The ability to produce a disease

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13
Q

Virulence

A

Degree of pathogenicity

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14
Q

Virulence factors

A

Characteristics conferring virulence. Assist the pathogen in colonizing the host’s cells

Example: Toxins, capsule, degradative enzymes…

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15
Q

Infection

A

Multiplication of the pathogen in the host

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16
Q

Disease

A

Alteration in physiology due to infection

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17
Q

Direct damage is due to

A

Bacteria and their products

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18
Q

Indirect damage

A

Immunopathology (inflammation, complement s…)
Exagerated immune response
Chronicity of the infection

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19
Q

Sequence of events leading to disease

A

Transmission
Colonization and growth at the inoculation site
Tissue invasion/virulence factor product•
Immune response in the host
Resolution or infectious disease

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20
Q

Routes of transmission

A

Respiratory: Flugge drops
Gastrointestinal: fecal-oral
Genital : STD
Skin : wounds, puncture

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21
Q

Steps of pathogenesis

A

Transmission
Adherence
Invasiveness
Toxin production
Persisting in a new environment

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22
Q

Adhesion via

A

Adhesins
Fimbriae
Glycocalyx (capsule and slime layer)

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23
Q

Invasiveness def and via

A

Entry into host cells and tissues as a strategy for bacterial survival and multiplication

Via enzymes (to destroy the tissue) and immune response evasion (capsule to evade macrophages)

24
Q

Enzymes invasion

A
  • Collagenase and hyaluronidase
    Damage connective tissue
  • Proteases. Destroys protein such as immunoglobulin
  • Leukocidine. Pore forming protein
  • Lecithinase and phospholipase (destroy the tissues)
25
Q

Toxin production

A

Damages other cells or functional abnormalities
Exotoxins
Endotoxins

26
Q

Exotoxins +ex

A

Secreted in a soluble form into the media
Encoded by plasmids or phages
Both gram + -
Exemple dipheteria, tetanus, botulinum toxins

27
Q

Endotoxins

A

Lipopolysaccharide on gram -
Encoded on chromosome
Protects the bacteria
Systemic effects such as fever or hypotension

Can lead to toxic shock

28
Q

Persisting in a new environment
(Not being recognized)

A

Encapsulation
Intracellular replication
Evasion of complement system action
Antigenic variation
Antigenic masking
Destruction of phagocytes
Proteases for igA (destroys igA)

29
Q

Encapsulation definition and function

A

Isolation of the cell in a semi permeable membrane allowing the entrance of nutrients and gases but not the host immune cells.
Also resemblance to host tissue components

30
Q

Intracellular replication permitted because of

A

Inhibition of phagolysosome fusion
Resistance to lysosomal enzymes
Escape form phagosome and grow in cytoplasm

31
Q

Antigen masking

A

On their surface, foreign molecules have receptors for Fc, so antigen bind and the molecule is not recognized

32
Q

Criteria for proving the causal relationship between a microorganism and specific disease according to Koch

A
  1. The microorganism must be present in every case of the disease but
    absent from healthy organisms.
  2. The suspected microorganism must be isolated and grown in a pure
    culture.
  3. The same disease must result when the isolated microorganism is
    inoculated into a healthy host.
  4. The same microorganism must be isolated again from the diseased
33
Q

Limitations of Koch postulate

A
  • some pathogens cannot be grown in pure culture outside the host (E.g.
    Mycobacterium leprae)
  • some pathogens grow only in humans
  • some pathogens produce more than one disease
  • opportunistic pathogens
  • polymicrobial diseases
34
Q

Normal flora or microbiota

A

Microorganisms (bacteria and fungi) that colonize the healthy human body
Called resident microorganisms

35
Q

Human microbiome

A

Genome of the normal microbiota

36
Q

Human microbiome project

A

Understand the role played by resident microbial ecosystems in heath and diseases

37
Q

Normal flora function

A

Provided metabolic functions like synthesis of vitamin B and K
Stimulates immunity
Prevents colonization from unwanted pathogens

38
Q

What influences normal flora

A

Anatomical location
Diet
Water
Medicines
Personal hygiene

39
Q

The disruption of normal flora is called

A

Dysbiosis

40
Q

Diseases related to microbiota

A

Disruption of normal flora, dysbiosis

Breach of natural barriers
- in the case of immunosuppression can cause infection because grow more
- close to where the normally inhabit exemple anus vagina
- not be in natural place

41
Q

Microorganisms in skin where and type

A

Entry : sweat glands, hair follicle, sebaceous glands
Abundant in folds (moisture and acidity)
Essentially gram + bacteria:
- staphylococcus epidermidis / aureus
- Propionibacterium acnes
- Corynebacterium

42
Q

External ear

A

Similar to skin microbiota

43
Q

Microorganisms in eyes

A

Similar to skin flora
Nasal communication: if infection in nose, can spread to eyes

44
Q

Naso and oropharynx microorganisms

A

Non pathogenic Neisseria and Haemophilus,
Streptococcus viridans, bacteroids and some Clostridium in abundance

Streptococcus viridans, nonpathogenic neiserias and the
Staphylococcus epidermidis inhibit the growth of:
Streptococcus pyogenes,
Neisseria meningitidis and Staphylococcus aureus, all
disease-causing more or less severe.

45
Q

Esophagus microorganisms

A

Oropharyngeal bacteria and yeast

46
Q

Stomach microorganisms

A

Helicobacter pilori

47
Q

Intestines microorganisms

A

Intestine: Enterobacteriaceae (type of negative bacilli) and
anaerobes

-Bacteroides fragilis
-Escherichia coli
-Clostridium perfringens
-Enterococcus faecalis
-Lactobacilli

48
Q

Amount of microorganisms in the gastrointestinal tract

A

From almost 0 in the stomach to a billion per gram of intestinal content in the colon

49
Q

Normal urine is…

A

Sterile but close to anus, that’s why infections. Caused by gastrointestinal flora: E. coli, Proteus, enterococcus faecalis

50
Q

Flora of the vagina

A

Lactobacillus ferment glucose on vaginal cells producing lactic acid. The low pH control he growth of Candida.

  • Gram positive and gram negative bacteria Staphylococcus, Enterococcus, Enterobacteria etc.)
  • candida
51
Q

Flora of distal portion of urethra

A

S. epidermidis. E. faecalis, Corynebacterium spp.

52
Q

Probiotics

A

> Probiotics: alive microorganisms that when administered in a appropriate dosis benefits the host.

53
Q

Prebiotic

A

non digestible ingredients (typically soluble fiber) that stimulate the growth and/or activity of the beneficial microbiota .

E.g. fructo-oligosaccharides that favor the growth of bifidobacteria.

54
Q

Symbiotics

A

probiotics + prebiotics.

E.g. oligofructose and bifidobacteria.

55
Q

How are called the microorganisms living in a healthy human being

A

Resident microorganisms

Microbiology (12 decks)

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