Microbes and Normal Flora Flashcards Preview

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Flashcards in Microbes and Normal Flora Deck (20)
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1
Q

What are the classes of microbial organisms?

A

Viruses
Bacteria
Fungi
Protozoa

2
Q

Viruses

A

RNA or DNA
No independent metabolism- can only exist in other cells
No organelles
Simple protein coat (cell membrane from host cell)

Eg:
Influenza
Rhinovirus
Herpes simplex
Ebola/Lassa
HIV
3
Q

Bacteria

A

DNA as a single chromosome
Independent metabolism
No organelles
Cell wall

Pepticoglycan cell wall= gram stain -ve

Lipopolysaccharide cell wall= gram stain +ve

4
Q

Fungi

A

DNA as multiple chromosomes
Independent metabolism and organelles
Cell wall

E.g Candida (candidiasis- thrush)

5
Q

Protozoa

A

DNA as multiple chromosomes
Independent metabolism
Organelles
Cell membrane

E.g. Giardia

6
Q

What do positive and negative gram stains indicate?

A

+ve: peptidoglycan cell wall

-ve: lipopolysaccharide cell wall

7
Q

What are the classes of bacteria?

A

Classified on gram staining and shape:

Gram stain +ve or -ve
Coccus (round) or bacillus (rod/elongated shape)

8
Q

Example of a gram positive cocci

A

Staphylococcus aureus and streptococcus species

9
Q

Example of gram negative cocci

A

Haemophilus influenzae

10
Q

Example of gram positive bacilli

A

Bacillus anthracis and lactobacilli species

11
Q

Example of gram negative bacilli

A

Salmonella, Escherichia coli (E Coli)

12
Q

Define symbiotic relationships

A

Close, long term interaction between 2 different species

Can be mutualistic, commensal or parasitic

13
Q

Define mutualistic interactions

A

Both parties benefit

14
Q

Define commensal interactions

A

One party benefits, no harm to the other party
E.g. colonisation
Normal gut flora

15
Q

Define parasitic interactions

A

One party benefits, the other is harmed.

16
Q

Define infection

A

Invasion and multiplication of microbes in an area of the body where they are not normally present. May cause symptoms or not. Does not necessarily cause disease.

17
Q

Define pathogen

A

Micro organism able to cause disease

18
Q

Define obligate pathogen

A

Pathogen that must cause disease in order to be transmitted from one host to another. Must infect host in order to survive.

19
Q

Define opportunistic pathogen

A

A pathogen that takes advantage of an opportunity not normally present, such as a host with a weak immune system (i.e. breached integumentary barrier, disrupted gut flora)

20
Q

What effects can antibiotics have on normal microbiota?

A

Can kill normal flora, allowing opportunity for pathological bacteria to invade (e.g. clostridium difficile)