Infections On Surfaces Flashcards Preview

[ ESA 3- Infection and Immunity > Infections On Surfaces > Flashcards

Flashcards in Infections On Surfaces Deck (71):
1

What is meant by a surface?

Any interface between a solid and either a liquid or a gas

2

What does the microbiota consist of?

The microorganisms that are carried on the skin and mucosal surfaces

3

What is normally true of the microbiota?

They are normally harmless, or even beneficial

4

When can microbiota be harmful?

When they transfer to other sites

5

What are the categories of normal skin flora?

Gram positive coccus
Gram positive bacilli

6

What are the gram positive coccus found in the skin flora?

Staphylococcus aureus
Staphylococcus epidermidis
Streptococcus species

7

What are the gram positive bacilli found in the skin flora?

Corynebacterium species
Propionibacterium species

8

What are the mucosal flora found in the eye?

Coagulase negative staph
Diphtheroids
Saprophytic neisseria species
Viridans group streptococci

9

What are the mucosal flora found in the nares?

Staph aureus

10

What are the mucosal flora found in the nasopharynx?

Neisseria meningitidis
Streptococcus pneumoniae
Haemophilus influenzae

11

What are the mucosal flora found in the mouth?

Viridans streptococci
Neisseria
Veillonella
Lactobacillus
Actinomyces
Bacteroides
Capnocytophaga
Eikenella
Prevotella
Fusobacteria
Clostridia
Propionibacteria
Candida
Ceotrichum species

12

What are the mucosal flora found in the stomach?

Helicobacter
Streptococci
Staphylococci
Lactobacilli

13

What are the mucosal flora found in the intestine?

Bacteroides
Bifidobacterium
Eubacterium
Lactobacillus
Coliforms
Aerobic and anaerobic streptococci
Clostridium
Yeasts

14

What are the mucosal flora found in the urethra?

Enterobacteriaceae
Lactobacilli
Diphtheroids
Alpha and non-haemolytic streptococci
Entercocci

15

What are the mucosal flora found in the vagina?

Lactobacilli
Diphtheroids
Micrococci
Coagulase-negative staphlococci
Enterococcus faecalis
Microaerophilic and anaerobic streptococci
Mycoplasmas
Ureaplasmas
Yeasts

16

How is a coagulase test conducted?

By testing for coagulase in a test tube

17

How can you tell if coagulase is being produced in a coagulase test?

If plasma clots on addition of bacteria

18

What does a positive coagulase test indicate?

The staphylococcus in question is staph aureus- all other staphylococci are coagulase negative

19

What is the problem with surface infections?

They can be a major cause of hospital acquired infection

20

How can surface infections be acquired in hospitals?

Prosthetic surfaces that are implanted during surgeries
Infections of the mucosa or skin caused by procedures or invasive devices

21

What prosthetic surfaces implanted during surgery can cause a surface infection?

Pacemaker
Joint replacements

22

What invasive devices can result in a hospital acquired surface infection?

Cannulas
Catheters

23

How can the majority of hospital acquired surface infections be prevented?

Proper sterilisation of surfaces
Care during the procedure

24

What is the problem with HAIs?

Cost a large amount of money
Have a large negative impact on the outcome of treatment, and can often even cause death

25

Why do HAIs cost a large amount of money?

Cost of investigations
Treatments
Extended hospital stays
Loss of reputation and subsequent funding

26

Give 6 internal infections on natural surfaces

Cellulitis
Pharyngitis
Conjunctivitis
Gastroenteritis
UTI
Pneumonia

27

What pathogens can cause cellulitis?

Strep. pyogenes
Clostridium perfingens

28

What pathogens can cause pharyngitis?

Strep. Pyogenes
Mycoplasma pneumoniae
Adenovirus

29

What pathogens can cause conjunctivitis?

Adenovirus
Staphlococcus aureus

30

What pathogens can cause gastroenteritis?

Salmonella
Norovirus
Rotavirus

31

What pathogens can cause UTIs?

E. coli
Staph. Saphrophyticus
Klebsiella

32

What pathogens can cause pneumonia?

Strep. Pneumoniae
Staph. Aureus
Haemophilus influenza

33

Give 5 external infections on natural surfaces

Endocarditis
Vasculitis
Septic arthritis
Osteomyelitis
Empyema

34

What pathogens can cause endocarditis?

Staph. Aureus
Strep. Mutans
Pseudomonas

35

What pathogens can cause vasculitis?

HTLV-1 (human T-cell lymphotrophic virus)

36

What does HTLV-1 cause?

Retinal vasculitis

37

What pathogens can cause septic arthritis?

Neisseria gonorrhoea
Haemophilus influenzae

38

What pathogens can cause osteomyelitis?

Staph. Aureus
Aspergillus

39

What is empyema?

Infection between pleural membranes

40

What pathogens can cause empyema?

Strep. Pneumoniae
Staph. Aureus

41

What prosthetic surfaces can get infected?

Intravascular lines
Peritoneal dialysis catheters
Prosthetic joints
Cardiac valves
Pacing wires
Endovascular grafts
Ventrico-peritoneal shunts

42

What pathogens cause infection on prosthetic joints?

Coagulase negative staphylococcus
Staph aureus

43

What are the categories of infection on cardiac valves?

Native valves and prosthetic valve endocarditis >1 year post op
Prosthetic valve endocarditis <1 year post-op

44

What pathogens can cause native valves and prosthetic valve endocarditis >1 year post op?

Viridans streptococci
Staph. Aureus
Candida
HACEK group

45

What pathogens can cause prosthetic valve endocarditis <1 year post-op?

Coagulase negative staph

46

What infection can occur on pacing wires?

Cardiac pacing wire endocarditis

47

What pathogens can cause cardiac pacing wire endocarditis?

Coagulase negative staph
Staph. Aureus

48

What are the steps in the pathogenesis of infections at a surface?

Adherence to host cells or prosthetic surface
Biofilm formation
Quorom secretion
Invasion and multiplication
Host response

49

What enhance adherence to host cells or prosthetic surface?

Pili or fimbriae

50

How do biofilms form?

Bacteria excrete polymers which bind with water molecules to form a slimy matrix
The bacteria become embedded within the 'gel'

51

What polymers can bacteria excrete to produce biofilms?

Proteins
Lipids
Nucleotides

52

Why do biofilms aid bacterial survival?

These bacteria have a slower turnover
Antibiotics don't work or attach as well
Nutrients can't diffuse into the matrix
Chemical gradients create microenvironments for different microbial species

53

What is the purpose of quorom secretion?

Intracellular communication between bacteria

54

What does intracellular communication between bacteria using quorom secretion involve?

Signalling molecules
Cell surface or cytoplasmic receptors
Gene expression

55

What signalling molecules are involved in quorom secretion?

Autoinducers

56

What is the purpose of gene expression in quorom secretion?

Co-operative behaviours and more AI production

57

What does quorom secretion allow?

Bacteria to sense the number of nearby bacteria

58

What happens if, through quorom secretion, the bacteria can sense the number of bacteria is big enough?

Biofilm can be formed

59

What does quorum sensing control?

Sporulation
Virulence factor secretion

60

What can the host response to infections at surfaces involve?

Pyogenic response
Granulomatous

61

What happens in a pyogenic response?

Neutrophils produce pus

62

What happens in a granulomatous response?

Fibroblasts, lymphocytes, and macrophages produce nodular inflammatory lesions

63

What are the main steps in managing infected surfaces?

Diagnosis
Treatment
Prevention

64

What is the aim of diagnosis in the management of infected surfaces?

Identify infecting organism and its antimicrobial susceptibilities

65

How can an infected surface diagnosis be made?

Blood cultures
Tissue/prosthetic material sonication and culture

66

What are the challenges in diagnosis of infected surfaces?

Adherent organisms
Low metabolic state/small colony variants

67

What is the aim of treatment of infected surfaces?

Sterilise tissue and reduce bioburden

68

How can infected surfaces be treated?

Antibacterials
Remove prosthetic material
Surgery to resect infected material

69

What are the challenges in the treatment of infected surfaces?

Poor antibacterial penetration into biofilm
Low metabolic activity of biofilm microorganisms
Dangers/difficulties of surgery

70

How can infection on natural surfaces be prevented?

Maintain surface integrity
Prevent bacterial surface colonisation
Remove colonising bacteria

71

How can infection on prosthetic surfaces be prevented?

Prevent contamination
Inhibit surface colonisation
Remove colonising bactera