Systemic Bacteriology 2

Question 1

What is virulence?

Answer 1

The ability of a microbe to cause damage to the host

Question 2

What is an opportunistic pathogen?

Answer 2

One that causes infection when a change in the natural immunity arises

Question 3

What is an endogenous pathogen?

Answer 3

One that is already in the body that becomes pathogenic

Question 4

What is an exogenous pathogen?

Answer 4

One that comes from outside the host

Question 5

What are commensal pathogen?

Answer 5

Ones that are part of the normal flora

Question 6

What are bacteria?

Answer 6

Prokaryotic, single celled organisms

Question 7

What are the main infectious agents?

Answer 7

Bacteria
Viruses
Fungi
Protozoa

Question 8

What are three examples of protozoa?

Answer 8

Amoeba
Plasmodium
Toxoplasma

Question 9

What are two examples of gram negative prokaryotic pathogens?

Answer 9

Neisseria

Escherichia

Question 10

What are four examples of gram positive prokaryotic pathogens?

Answer 10

Streptococcus
Staphylococcus
Enterococcus
Clostridia

Question 11

What are the two species of neisseria that are pathogenic?

Answer 11

Neisseria meningitidis

Neisseria gonorrhoeae

Question 12

How do gram negative cocci appear on gram film?

Answer 12

In pairs - diplococci

Question 13

What are the two types of gram negative bacteria that are associated with the GI tract?

Answer 13

Gut commensal coliforms

Significant gut pathogens

Question 14

What are examples of gut commensal coliforms?

Answer 14

Most strains of E. coli
Klebsiella
Enterobacter
Proteus

Question 15

What are examples of significant gut pathogens?

Answer 15

Salmonella
Shigella
Verotoxin producing E. coli

Question 16

What are coliforms?

Answer 16

Species of gram negative bacteria that look like E. coli on gram film and when cultured on blood agar

Question 17

Are coliforms aerobic or anaerobic?

Answer 17

Grow best aerobically but can grow anaerobically

Question 18

How are coliforms differentiated from each other?

Answer 18

Biochemical structures

Antigenic structure of cell wall - O and H antigens

Question 19

What can coliforms cause when they get into normally sterile sites?

Answer 19

UTI
Peritonitis
Bilary tract infection

Question 20

What is the first line antibiotic used for treatment of infections caused by coliforms?

Answer 20

Gentamicin

Question 21

Why do patients with coliform sepsis become very unwell very quickly?

Answer 21

Because of the endotoxin released from the gram negative cell wall when the bacteria die

Question 22

What is the O antigen?

Answer 22

Cell wall

Question 23

What is the H antigen?

Answer 23

Flagella

Question 24

What is sepsis?

Answer 24

Host response to severe infection

Question 25

What are on the outer membrane of gram negative bacteria?

Answer 25

Asymmetric membrane Lipopolysaccharides Peptidoglycan Lipoproteins

Question 26

What happens in the body during sepsis? (4)

Answer 26

Small blood vessels become permeable and lose fluid into the tissues Lower blood volume requires the heart to work harder to maintain oxygenation of the tissues so HR increases Poor tissue oxygen perfusion means blood supply to less essential organs is shut down Blood clotting system activated causing clotting in tiny vessels which uses up all clotting factors so increased risk of haemorrhage

Question 27

What are the stages of sepsis in increasing severity?

Answer 27

Infectin Sepsis Severe sepsis Septic shock

Question 28

What are examples of streptococcus?

Answer 28

Pneumonia | Group A Streptococcus

Question 29

What is an example of enterococcus?

Answer 29

Enteric infection

Question 30

What does GAS stand for?

Answer 30

Group A streptococci

Question 31

How are streptococci classified and what are the groups?

Answer 31

Haemolysis | Alpha, beta, gamma

Question 32

What type of haemolysis are GAS?

Answer 32

Beta

Question 33

What is alpha-haemolysis

Answer 33

Partial haemolysis | Caused by enzymes that denature the haemoglobin inside red blood cells causing greenish discolouration

Question 34

What is beta-haemolysis?

Answer 34

Complete haemolysis | Caused by enzymes that break down red blood cells causing complete clearing around the colony

Question 35

Which are the most pathogenic streptococci?

Answer 35

Beta-haemolytic

Question 36

What is gamma-haemolysis?

Answer 36

No haemolysis

Question 37

What are examples of diseases associated with Group A Streptococci?

Answer 37

Streptococcus pyogenes Bete-haemolytic Streptococcal sore throat Invasive diseases

Question 38

What is pneumonia?

Answer 38

An acute inflammation of th lungs, often caused by inhales pneumococci of the species streptococcus pneumoniae The alveoli and bronchioles of the lung become plugged with a fibrous exudate

Question 39

What are GAS a major cause of?

Answer 39

Skin diseases | Autoimmune disease

Question 40

What kind of haemolysis do streptococcus pneumoniae cause?

Answer 40

Alpha

Question 41

What is the most important group of non-haemolytic streptococci?

Answer 41

Enterococci

Question 42

What are the two types of enterococci?

Answer 42

Enterococcus faecalis | Enterococcus faecium

Question 43

In what way are enterococci dangerous?

Answer 43

Can cause problems if the y get into a normally sterile site

Question 44

What are enterococci a common cause of?

Answer 44

UTI

Question 45

What antibiotic are most strains of enterococci sensitive to?

Answer 45

Amoxicillin

Question 46

What are two species of staphylococcus?

Answer 46

S. aureus | S. epidermidis

Question 47

Are staphylococci gram positive or negative?

Answer 47

Positive

Question 48

What is an example of an S. aureus infection?

Answer 48

MRSA

Question 49

What does nosocomial mean?

Answer 49

Originating in hospital

Question 50

Where is MRSA usually acquired and who by?

Answer 50

Hospital | Elderly and immunocompromised

Question 51

Are clostridium gram positive or negative, and are they aerobic or anaerobic?

Answer 51

Positive | Anaerobic

Question 52

What do clostridium produce? (2)

Answer 52

Spores that can survive outside the body for months | Exotoxins that can use severe tissue damage

Question 53

What is an example of clostridium?

Answer 53

Clostridium difficile (C. difficile)