systemic bacteriology 2

Question 1

virulence

Answer 1

the capacity of a microbe to cause damage to its host

Question 2

Pathogen:

Answer 2

a harmful organism that produces a pathology

Question 3

Commensal:

Answer 3

an organism that is part of the normal flora
- Often a mutualistic relationship
- Endogenous

Question 4

Opportunistic pathogen:

Answer 4

an organism that causes infection when opportunity/change in natural immunity arises

Question 5

Coagulase test:

Answer 5

use to differentiate between Staph. aureus and coagulase negative Staph. (including Staph epidermis)

Question 6

Haemolysis:

Answer 6

used to differentiate between Streptococci

Question 7

during sepsis what happens to small blood vessels and what does this result in

Answer 7

they become ‘leaky’ and loose fluid into tissues - decreased blood volume so heart has to work harder

Question 8

what does poor tissue perfusion in sepsis mean

Answer 8

blood supply to less essential organs is shut down

Question 9

what happens when the blood clotting system is activated in sepsis

Answer 9

uses all clotting factors, increasing risk of haemorrhage

Question 10

what happens to patients with gram-negative sepsis

Answer 10

they get very unwell very quickly due to endotoxin released when Gram-negative bacteria die

Question 11

describe the first stage of a fever

Answer 11

Antigen/LPS interacts with macrophages

Question 12

describe the second stage of a fever

Answer 12

Macrophages release cytokines into bloodstream

Question 13

describe the third stage of a fever

Answer 13

Cytokines travel to anterior hypothalamus

Question 14

describe the fourth stage of a fever

Answer 14

Prostaglandin E released - increases body’s thermal set point

Question 15

describe the fifth stage of a fever

Answer 15

Body perceives it as cold - starts to ‘shiver’

Question 16

Neisseria meningitidis:

Answer 16

most common cause of bacterial meningitis

Question 17

Neisseria gonorrhoeae:

Answer 17

gonorrhea

Question 18

Gram-negative cocci associated with GI tract

Answer 18

ut commensal coliforms

Many are part of normal bowl flora

Any coliform that gets into a normally sterile environment can cause infection e.g. UTI

Gentamicin is the first line antibiotic for the treatment of infections caused by coliforms

Question 19

Streptococcus spp

Answer 19

Identified by haemolysis (ONLY streptococcus)

Question 20

GAS:

Answer 20

numerous associated diseases e.g. Scarlet fever, impetigo, β-haemolytic

Question 21

Streptococcus pneumoniae:

Answer 21

pneumonia, ⍺-haemolytic

Question 22

Staphylococcus epidermis

Answer 22

• Nosocomial - associated with foreign devices e.g. catheters
• Coagulase negative

Question 23

Staphylococcus aureus

Answer 23

• Nosocomial and community
• Most common cause of skin, soft tissue and wound infection
• Sepsis
• Coagulase positive (appears golden)
• Clump forming - looks like grapes

Question 24

Enterococcus

Answer 24

• Enteric infections
• Part of normal bowel flora, can cause problems if they get into a normally sterile area
• 𝛾-haemolytic

Question 25

Clostridium spp.

Answer 25

• Part of normal bowel flora
• Produce endotoxins that can cause severe tissue damage

Question 26

Clostridium difficile:

Answer 26

• causes antibiotic-associated diarrhoea, especially in the elderly
• Proliferates in the absence of normal flora