bacteriology

Question 1

gram positive vs gram negative and what colour are they both in a gram stain

Answer 1

gram negative

• has thin peptidoglycan
• has lipopolysaccharide
• so stains pink
• mostly resistant to penicillins and vancomycin

gram positive

• retains blue black
• thick peptidoglycans
• some have spores
• mostly sensitive to penicillin and vancomycin

Question 2

s.aureus type of bacteria

Answer 2

gram positive staphylococcus coagulase negative

Question 3

how are s.a infections normally found

Answer 3

• pus forming
• blood stream
• often device related
• toxin illness

Question 4

what are the coagulase negative staph

Answer 4

s.epidermidis and s.capitis normally only pathogenic in foreign body

Question 5

3 types of gram positive coccus

Answer 5

• staphylococcus
• streptococcus
• enterococcus

Question 6

what colour are the two beta haemolysis of strep

Answer 6

alpha= green

beta=gold

Question 7

what is beta haemolysis group a strep

Answer 7

strep.pyogenes
-tonsilitis
strep throat
cellulitis
severe soft tissue infection
-puerpal sepsis

Question 8

what is beta haemolysis group b strep

Answer 8

• strep.agalactiae
• normal rectal and vaginal flora
• neonatal meningitis, bacteraemia, pneumonia
• immunocompromised adults

Question 9

2 main types of alpha haemolysis

Answer 9

strep.pneumoniae

virirdans

Question 10

strep pneumoniae what does it cause

Answer 10

• CAP
• meningitis
• bronchitis in COPD

Question 11

what are the viridans strep

Answer 11

-commensal or mucosal flora that stick to things eg heart valves causing endocarditis

Question 12

what are the enterococci bacteria found and hwere

Answer 12

• in the gut

- involved in intra-abdominal sepsis, UTI and bacteraemia

Question 13

what does VRE stand for

Answer 13

vancomycin resistant enterococci

Question 14

3 gram positive bacilli

Answer 14

• bacillus
• corynebacterium
• listeria

Question 15

reservoir for anthracis and what they cause and transmission

Answer 15

• reservoir of soil and domestic antimals herbivores eg cows
• human infected by cutaneous inoculation IVDU or inhalation
• cause anthrax disease= get small blisters and fever, chest pain

Question 16

corynebacterium diptheriae

• transmission
• pathology
• prevention

Answer 16

• spread person to person by respiratory droplets
• bacteria in pseudomembrane in throat: potential suffocation
• diptheria toxin produced in throat, via bloodstream then inhibits protein synthesis in heart (cardiac failure) and peripheral nerve

Question 17

what do listeria monocytes do and where are they found

Answer 17

-intrauterine/ neonatal septicaemia/ meningitis
risk in pregnancy from foods like
-soft cheese
-coleslaw

Question 18

gram positive anaerobes 4 types

Answer 18

• coccus

- bacillus: clostridia

Question 19

4 main types of clostridia

Answer 19

• clostridium tetani
• clostridium botulinum
• clostridium difficile
• clostridium perfringens

Question 20

clostridium tetani

• transmission
• pathology
• symptoms
• prevention

Answer 20

-transmission: spores ubiquitous in soil, soil then contaminates
-toxin mediated neuro-toxin causes excitation of motor neurones by blocking release of inhibitor GABA
SYMPTOMS: spasm, rigidity
prevention: vaccine

Question 21

clostridium botulinum

• reservoir
• pathology
• symptoms
• prevention

Answer 21

• reservoir: food borne as germinates in soil
• toxin: neuro-toxin prevents release of acetylcholine
• symptoms: symmetrical flaccid paralysis
• prevention: standards of food prep

Question 22

clostridium difficile

-transmission

Answer 22

ingestion in spores

from soil

Question 23

clostridium perfringens
-infections
transmission
pathology -main toxin

Answer 23

• gas gangrene and other ssti
  transmission: sores in soil to human gut
• toxin mediated disease: main toxin is alpha toxin- lecithinase so damages cell membrane including haemolysis

Question 24

what are the gram negative aerobic cocci

Answer 24

neisseria gonorrhoea
neisseria meningitidis
moraxellla cattharalis
other(commensal) neisseria in mouth

Question 25

what is a coliform

Answer 25

also called the enterobacteriaceae - bacteria that are rod shaped gram negative non-spore forming which can ferment lactulose eg - e.coli - klebsiella - salmonella

Question 26

what is the commonest aerobic GNB in the gut

Answer 26

e.coli

Question 27

what is the VTEC strain of e.coli

Answer 27

e.coli 0157 causes haemorrhage can lead to HUS haemorrhagic uraemic syndrome

Question 28

what are the main causes of UTI

Answer 28

e.coli | klebsiella

Question 29

reservoir shigella

Answer 29

humans only

Question 30

reservoir salmonella

Answer 30

multiple species whose host include all mammals, birds and reptiles -faeces spread in humans in water

Question 31

pseudomonas aeruginosa reservoir -pathology and who it affects most

Answer 31

- environment especially water - human respiratory pathogen where biolfilms important - immunocompromised eg CF, long term lung conditions - common coloniser eg leg ulcers

Question 32

burkholderia cepacia - reservoir - who it affects

Answer 32

- reservoir soils and plants | - now a pathogen in CF

Question 33

vibrio cholerae - reservoir - toxin pathology - pathology - treatment

Answer 33

reservoir: warm salt water and spread by faeces - toxin mediated disease: increased cAMP in cells, decrease in Na uptake and increased Cl secretion - massive water loss and rice water stools - electrolyte problem

Question 34

what is the commonest bacterial cause of gastroenteritis in the UK

Answer 34

-campylobacter found in birds

Question 35

what does h.influenzae cause 2 types

Answer 35

- unencapsulated strains are common cause respiratory tract infections - capsulated serotype b causes meningitis in young children

Question 36

what does leigonella cause and where is its reservoir

Answer 36

- causes severe pneumonia | - lives in natural and engineered water systems inside amoebae

Question 37

what does helicobacter produce

Answer 37

urease breaks down urea to ammonia to buffer stomach conditions

Question 38

what do bacteroides cause

Answer 38

assoc. to intrabdominal and ssti infections | resistant to penicillin

Question 39

what do fusobacterium cause

Answer 39

- head and neck infections including brain abscesses - mixed intra-abdominal infection - perirectal abscess

Question 40

3 small bacteria

Answer 40

- chlamydia - mycoplasma pneumoniae - rickettsia

Question 41

how are the small bacteria different to other bacteria

Answer 41

smaller dont grown on agar plate lack normal cell wall

Question 42

what is rickettsia and what cells does it like

Answer 42

obligate intracellular parasites | likes endothelial cells with skin lesions and vasculitis

Question 43

what does chlamydia trachoma cause

Answer 43

chronic eye infection

Question 44

what does chlamydophila pneum and chlamydophila psittaci cause

Answer 44

both cause pneumonia | psittaci in birds