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Flashcards in microbiology Deck (166)
1

how does strongyloides cause hyperinfection with gram negatives

when strongyloides pentrates through tissue walls --> go into circulation (can bring gram negative organisms with it into the blood) = sepsis

2

what is the proper name for worms

helminths

3

what is a paratenic host

host in which the parasite enters the body and does not undergo development, but remains infective (does not change into different parts of its life cycle)

3

what are the two main ways of catching toxoplasma gondii

- from cats faeces - undercooked meat

4

Who does Giardia classically infect

children - poor hand hygiene

4

symptoms of enterobius ermicularis

many asymptomatic perianal/vaginal itch

4

what are the 2 types of taeniasis

taenia saginate taenia doium

5

What is pathotyping mainly used for?

determining which virulence type it is - for E coli

5

what does echinococcus granulosus cause

hydatid cysts

6

why are type 3 secretion systems special

because it is used by pathogens to make a protein go directly from the cytoplasm of the bacteria to the cytoplasm of the host cell

7

What type of diarrhoea does EHEC cause? Which population is mostly affected?

- bloody diarrhoea - any age, developed coutries

8

life cycle of enterobius ermicularis

eggs ingested by humans --> hatch --> at night, females will crawl out and lay eggs around the anus and then go back in during the day --> itch --> hand in mouth

9

what are the aetiological agents of travellers' diarrhoea

ETEC other bacteria viruses protozoa

9

2 types of parasites

ectoparasites protozoal parasites

9

treatment of scabies

- ivermentin - oral - topical scabicides (need to be over long time period) - hot wash clothes and bed linen

9

what kind of helminth is strongyloides stercoralis

roundworm

10

Main food source of Salmenella

raw eggs

11

what is the difference between a definitive host and an intermediate host

definitive - parasite reaches sexual maturity in the host intermediate - development occurs but the parasite does not reach sexual maturity

12

proper name for ticks

Ixodes holocyclus

12

two main forms of protozoa

trophozoite - active cysts - inactive

13

definition of haemorrhagic colitis

inflammation of the colon --> blood in the faeces (but no pus)

13

life cycle of scabies

burrow into the epidermis --> come out to lay their eggs on the surface --> eggs hatch --> burrow into epidermis

14

infection by lice is known as

pediculosis

14

how long is taeniasis

up to 10m long

15

how much fluid goes into the GIT in 24 hours and how much is excreted

10 Litres goes in 100ml comes out

17

how does staph cause food poisoning

eat the pre formed toxin in food

18

what are the aetiological agents of food bourne gastro

Staph Salmenella Clostridium Bacillus Vibrio Listeria viruses ciguatoxin

18

Which E coli use the Type 3 secretion system

EPEC and EHEC

18

what is the helminth that is able to complete its life cycle in the human

strogyloides

19

3 major types of helminths

roundworms (nematodes) tapeworms flukes

19

where does Schiestosoma mansonii live when in humans

in the intestinal veins

19

what is taeniasis

cestode parasite cuaing cysticercosis in their intermediate host --> causes neurocystercercosis most regognisedc

20

Which E coli produces Shiga toxin

All EHEC and the occasional EAEC (from acquired bacteriophage)

21

What was the aim of the WHO diarrhoeal disease control program

- reduce diarrhoea-associated mortality - reduce incidence of diarrhoea through education and immunisation

23

what are the aetiological agents of dysentery

Shigella EIEC protozoa (Shigella or amoboe)

24

what is the aetiological agent of haemorrhagic colitis

EHEC

24

symptoms of ascaris lumbricoides

- can be asymptomatic - asthma - pneumonitis intestinal obstruction (pancreatitis, cholangitis etc)

25

treatments of taenia solium

antihelmintics (cautiously --> dont wan the cyst to burst)

26

life cycle of ascaris lumricoides

eggs mature in soil --> ingested --> penetrate intestinal wall --> hepatic circulation --> lungs --> alveolar space --> trachea --> reswallowed

27

How do Shiga toxins affect humans

affect protein synthesis

28

diagnosis of taenia solium

serology imaging techniques

29

what are the anti-diarrhoeals

- anti-motility agents - anti-secretory agents - binding agents

29

what is Schistosoma mansonii

fluke (trematode)

30

What are the methods use to try and diagnose what is causing diarrhoea?

- macroscopic appearance - microscopy - culture (bacteria) - antigen detection (viruses, parasites, toxins) - nucleic acid detection (viruses, bacteria, protozoa)

30

How do you know if Entamoeba histolytica has changed to pathogenic (as opposed to a commensal)

has Red cells inside it

30

treatment of enterobius ermicularis

antihelminthic (can be bought over the counter) - people tend to self treat

31

where abouts in Australia are ticks a problem

eastern australia

32

what does entamoeba histolytica do

- invades tissues in the colon --> large volume diarrhoea - can spread by blood and lodge in other areas causing abscess

33

what is dysentry

presence of blood, pus and mucus in the faeces

34

associations between diarrhoea and malnutrition

- increased energy loss (diarrhoea and vomiting and increased metabolic needs) - reduced energy intake (malabsorption and with-holding of food)

35

difference in stools between diarrhoea of small and large intestinal origin

small --> infrequent or frequent stools of large volume and watery large --> frequent stools of lowish volume

36

What is Tir?

It is the receptor for Intimin bacteria brings Tir with it --> pumps it from the cytoplasm from the bacteria --> cytoplasm of the cell

37

Which bacteria destroy the microvilli of the mucosa but do not invade it?

EPEC

37

what is in oral rehydration sachets

NaCl, KCl, bicarb, glucose/sucrose

37

T/F humans are part of the normal life cycle of ticks

false

37

what kind of worm is enterobius ermicularis

roundworm

38

what are the aetiological agents of antibiotic associated colitis

Clostridium difficile

38

what part of the life cycle are we for echinococcus granulosus

accidental

39

treatments of Schistosoma mansoni

antihelminitic - short courses effective

41

Pathotypes of diarrhoeagenic E coli

ETEC (toxigenic) EPEC (pathogenic) EHEC (haemorrhagic) EIEC (invasive) EAEC (aggregative)

42

Which bacteria systemically invade the body from the gut? How?

Salmenella (survive inside macrophages)

43

disease control for strongyloides

sewage disposal shoes

44

Diagnosis of strongyloides

eggs in the feaces serolgy

46

Adhesins of ETEC

CFA (colinising factor antigens)

47

what type of diarrhoea does EAEC cause? Which population is mostly affected?

- watery diarrhoea - children in LDCs

48

how do you diagnose echinococcus granulosus

imaging techniques seroogy

49

how are ticks normally transferred to humans

ticks climb up to the ends of long grass. As your leg brushes by --> jumps on

50

length of ascaris lumricoides

30-40cm

52

what are the functional areas of a LEE pathogenicity island

- Type 3 secretion system - effectors (toxins - that need the Type 3 SS to get out of the bacteria)

54

main reason for travellers diarrhoea

people from developed countries visit developing countries, where they have not encountered specific organisms before --> diarrhoea

54

main population that gets infected with enterobius ermicularis

young children

55

proper name for lice

pediculus.... humanis/capitis/pubis

56

Tx of ticks

removal of the tick

57

what are the aetiological agents of cholera-like gastro

vibrio cholerae ETEC

59

Which E coli can acquire the ability to produce Shiga toxin

EAEC - from bacteriophages

60

Which E coli produces Shiga toxins

EHEC

61

In which situations do you prescribe antibiotics for diarrhoea

- cholera - systemic infections (eg typhoid fever) - immunocompromised patients - severe infections with Shigella - protozoal infections - pseudomembranous colitis

62

What does intimin do?

a large outer membrane protein required for the intimate adherence between bacteria and cell.

63

Sx of ticks

paralysis (local or generalised ascending)

64

life cycle of lice

egg --> hatches --> several stages of malting --> adult --> lays eggs --> adult dies

65

Where does most of the fluid that goes into the GIT come from?

secretions of the GIT system

65

Tx of entamoeba histolytica

metnodizaole and paromomycin, drainage of abscess

66

diagnosis of Schistosoma mansoni

characteristic eggs in the faeces serolgy

68

what is a reservoir host

an animal which can be normally infected with a parasite that also infects people

69

what does toxoplasma gondii infect

all mammals, many birds

71

How do you go about culturing faeces

- enrichment for Salmonella and others - direct plating on selective/indicator media - confirm suspicious colonies using biochemical tests, serotyping and pathotyping

72

Which bacteria are the least invasive of the mucosa?

cholera ETEC --> adhere to intact intestinal mucosa

73

main animals that echinococcus granulosus nfects

dogs and cattle

74

what is ascaris lumricoides

a roundworm

75

what is the difference between the main infective causes of diarrhoea between developing and developed coutries

- developed countries - agent more likely to be viral - developing countries - agent more likely to be bacterial

76

how is diagnosis made of ascaris lumbricoides

- eggs in the faeces - imaging of obstructions

78

Which E coli have the LEE pathogenicity islands?

EHEC and EPEC

78

treatment of lice

topical insecticides

79

presentation of toxoplasma gondii

usually asymptomatic unless immunocompromised

80

when is toxoplasma gondii most infectious

from undercooked meat

81

what are the 2 primary sites for entamoeba histolytica abscesses

brain and liver

82

symptoms of Toxoplasma in immunocompromised patients

CNS lesions ocular disease in HIV

83

major problem of taeniasis

neurocystercercosis

84

what are two examples of tapeworms

echinococcus granulosus taeniasis

85

where abouts are scabies infection most seen on the body

fingerwebs elbows axillae genitals

86

treatment of echinococcus granulosus

surgery, PAIR, anthelmintics

87

what are the 2 scary things about stronglyoides

- can complete whole life cycle inside humans - can cause gram negative hyperinfection in immunocompromised hosts

87

main way we get taeniasis

eating the egg in the muscle of meat we eat

89

what is a pathogenicity island

a block of genes that are found on the chromosome in pathogens that are missing from non pathogens of the same species. Split into functional areas that work cooperatively.

90

diagnosis of giardia

cysts in the faeces

91

what are the important fimbriae and non fibriate adhesins in E coli

Fimbriae - CFAs of ETEC, BFP of EPEC non-fimbriate - Intimin of EPEC and EHEC

93

What type of diarrhoea does EPEC cause? Which population is mostly affected?

- non-specific gastroenteritis - children in LDCs

94

symptoms of taenia solium

cysts in subcutaneous and neural tissue

96

which E coli pathogen mostly affects people in developed countries

EHEC --> bloody diarrhoea

96

what causes the majority of symptoms of tapeworms

their excessive energy consumption

97

how do you get entamoeba histolytica

foecal-oral transmission (usually in the cystic stage)

99

What type of diarrhoea does EIEC cause? Which population is mostly affected?

- dysentery - any age, mainly in LDCs

101

main use for serotyping

to distinguish between different types of Salmonella

103

treatment of giardia

tinidazole

104

how does diarrhoea kill?

- fluid and electrolyte imbalance - delayed --> malnutrition

106

Which bacteria invade the mucosa but then dont go any further

Shigella

107

what are the virulence determinants

- adhesins - invasive activity - exotoxins - ability to resist killing

108

treatment of diarrhoea

- replace fluid and electrolytes (intravenous or oral) - reduce fluid loss

110

how do you get giardia intestinalis

faecal-oral transmission zoonotic transmission

111

mechanism behind diarrhoea of small intestinal origin

too much fluid enters a healthy colon - unable to absorb all the water --> diarrhoea

113

diagnosis of viral infections

antigen detection (mainly) - capture assay detection of nucleic acid - PCR electron microscopy

115

how does diarrhoea lead to malabsorption

gut villi are damaged by the organism --> malabsorption

116

what affects the pathogenicity of protozoa

host factors - eg. immunocompromise

118

what are the aetiological agents of enteric fever

Salmonella typhi Salmonella paratyphi

119

what happens with the cysts

proliferation internally in crypts producing infective protoscoeces

121

why did the modified shiga Toxin Receptor drug not work

because by the time you diagnose the patient, enough Shiga toxin has already been absorbed to make them really sick

122

how do you get schistosoma mansonii

trasmitted by fresh water snails --> larva penetrates the skin

124

how are lice and mites spread

direct contact

125

what type of cell cycle is taeniasis

humans can replace animal in the life cycle (but dont need to be involved)= - can be both definitive and intermediate hosts)

127

What does oral rehydraton not do?

reduce fluid loss

128

why do we test for toxoplasma in pregnancy

can go haematogenously --> to baby. Can cause miscarriage or birth defects

129

what is the proper name of pinworm

enterobius vermicularis

130

which E coli species have intimin as an adhesin

EPEC and EHEC

131

in the past, lice were vectors of

rickettsia and spirochetes

132

life cycle of stronglyoides

2 cycles: 1. eggs mature --> hatch and then penetrate skin 2. adults lay eggs in GI system --> eggs in faeces --> mouth (reinfection)

133

life cycle of schistosoma mansonii

gut --> liver --> portal venous system --> maturation in portal vein --> lay eggs in the BVs and lumen of the gut --> into the faeces --> hatch in water --> into fresh water snails

134

where do lice undergo their life cycle

the whole time they have to be in direct contact with the scalp

135

What type of diarrhoea does ETEC cause? Which population is mostly affected?

- watery diarrhoea - infants in LDCs, travellers

136

Sx of Schistosoma mansoni

cercarial dermatitis

138

What is bundle forming pili? and where are they found?

They are like CFAs of ETEC - allow the bacteria to stick to microvilli, stopping them from being washed away by peristaltic activity ONLY FOUND ON EPEC

139

what are the aetiological agents of non-specific gastro

viruses bacteria protozoa

140

how long is enterobius vermicularis

1cm

141

how do you diagnose toxoplasma gondii

serolgy

142

what percentage of death in children under 5 is caused by diarrhoea

11%

143

major importance of ticks

they can be vectors of other viral agents

145

How do anti-motility agents work

inhibit perstalisis

146

what is toxoplasma gondii

obligate intracellular parasite

147

symptoms of scabies

itch

148

what are some types of protozoal parasites

entamoeba histolyica giardia intestinalis toxoplasma gondii

149

treatment of strongyloides

antihelminthic

150

what is giardia intestinalis

a flagellate, primitive eukaroyte

151

aetiological agents (broadly) of diarrhoea

bacteria viruses protozoa

152

Why is the sand particle used for the drug of the modified Shiga Toxin Receptor

because without it, the receptor would insert into our gut membrane --> susceptible gut tissue

153

How do the different E coli cause different types of diarrhoea

they have different virulence factors

154

length of echinococcus granulosus

5mm

155

Which bacteria invade the submucosa and they drain to regional lymph nodes

Salmenlla Campylobacter

156

what are some types of ectoparasites

lice - insects mites - arachnid ticks arachnid

158

what stops head lice from infecting pubic hair

cant infect hair with oval hair follicles

159

what is special about lice and scabies in terms with their life cycle

they can fulfill their whole life cycle on a single host

160

where are hyatid cysts mostly seen

liver and lungs

161

proper name for mites/scabies

sarcoptes scabiei

162

why are anti-motility agents classed as "bad"?

- because the body is then unable to flush the toxin out of the body - doesnt stop the fluid coming out of the tissues

163

diagnosis of enterobius ermicularis

detection of eggs

164

Sx of acute 1st infection of Schistosoma mansoni

nonspecific fibrile illness with high cytokines

165

how does oral rehydration work

acts on the secondary absorption system in the villi (low MW compound is taken up over the villi, taking up Na and water with it passively)

166

how long can giardia cysts last for outside of thehost

2 months