infectious disease

Question 1

what can infectious diseases be caused by

Answer 1

bacteria
viruses
fungi
parasites
prions?

Question 2

what is an infection/infectious disease

Answer 2

the invasion, multiplication and establishment of one or more pathogens in the body

Question 3

where can infections begin

Answer 3

anywhere in the body and may spread all through it
disease can be localised or systemic

Question 4

pathogen

Answer 4

any organism which can inflict damage/disease on the host

Question 5

pathogenicity

Answer 5

the ability of an organism to inflict damage on the host

Question 6

virulence

Answer 6

the relative ability of a pathogenic organism to cause disease

Question 7

virulence factors

Answer 7

genes, molecules, or structures contributing to virulence

Question 8

pathogenesis

Answer 8

mechanism of disease production

Question 9

microbial colonisation

Answer 9

when microorganisms including those that may be pathogenic are present at a body site by are doing no harm and not causing symptoms of infection

Question 10

commensals

Answer 10

organisms that live in harmony with us

Question 11

primary pathogens

Answer 11

can cause disease in healthy subjects

Question 12

opportunist pathogens

Answer 12

organisms that behave as pathogens when given the right opportunity in a compromised host
may also be commensal or saprophytes

Question 13

saprophytes

Answer 13

organisms that live in the environment

Question 14

zoonoses

Answer 14

organisms associated with animals

Question 15

when do microorganisms cause disease

Answer 15

when host defences fail to control organisms
and/or
organisms overcome host defences

Question 16

physical defences - immediates

Answer 16

anatomical barriers
mechanical defences
microbial colonisation

Question 17

physiological defences

Answer 17

temperature
pH
chemical mediators

Question 18

endocytic and phagocytic early recognition of pathogens

Answer 18

endocytosis
phagocytosis

Question 19

function of physical barriers

Answer 19

deny entry to pathogens

Question 20

function of mechanical defences

Answer 20

remove pathogens from potential sites of infection

Question 21

function of microbiome

Answer 21

compete with pathogens for cellular binding sites and nutrients

Question 22

role of temperature

Answer 22

fever inhibits growth of some pathogens

Question 23

role of low pH

Answer 23

acidic pH of stomach kills most pathogens
low pH in vagina inhibits pathogens
low pH in urine inhibits pathogens

Question 24

role of chemical mediators

Answer 24

lysozyme cleaves bacteria
complement lyses microbes and/or facilitates phagocytosis (opsonisation)
interferon > antiviral defences in uninfected cells
cytokines recruit immune cells to infected area

Question 25

endocytosis

Answer 25

various cells internalise and breakdown foreign material

Question 26

phagocytosis

Answer 26

specialised cells (e.g. monocytes, neutrophils and tissue macrophages) internalise, kill and digest whole organisms

Question 27

inflammatory barriers

Answer 27

tissue damage and infection causes leakage of fluid. fluid contains serum proteins with antibacterial activity > influx of phagocytes

Question 28

what can bacterial virulence factors be

Answer 28

cytosolic cell membrane associated secreted

Question 29

what type of bacteria is staphylococcus aureus

Answer 29

gram positive responsible for superficial and deep seated infections

Question 30

what must successful pathogens do in order to infect respiratory tract

Answer 30

adhere to epithelial cell surface inhibit ciliary action avoid destruction by alveolar macrophages

Question 31

what type of bacteria is streptococcus pneumoniae

Answer 31

gram positive cocci (purple) leading cause of bacterial community acquired pneumonia

Question 32

urinary tract innate defence

Answer 32

bladder - regular flushing action - acidity of urine - urine normally 'sterile' - urothelial cells covered in protective mucous

Question 33

what type of bacteria is neisseria meningitidis

Answer 33

gram negative cocci

Question 34

diseases associated with neisseria meningitidis

Answer 34

meningitis meningococcemia with or without meningitis meningoencephalitis pneumonia arthritis urethritis

Question 35

most common cause of skin and soft tissue infections

Answer 35

s. aureus

Question 36

most common community acquired pneumonia

Answer 36

s. pneumoniae

Question 37

most common cause of UTI

Answer 37

e. coli

Question 38

2 most common causes of bacterial meningitis in adults and children

Answer 38

s. pneumoniae n. meningitidis

Question 39

why are hospital patients at great risk for new infections

Answer 39

vulnerable - immunocompromised impaired swallow? breach in physical defences prosthetic material loss of microbiome loss of cellular immunity