microbiology Flashcards
(166 cards)
1
Q
how does strongyloides cause hyperinfection with gram negatives
A
when strongyloides pentrates through tissue walls –> go into circulation (can bring gram negative organisms with it into the blood) = sepsis
2
Q
what is the proper name for worms
A
helminths
3
Q
what is a paratenic host
A
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
Q
what are the two main ways of catching toxoplasma gondii
A
- from cats faeces - undercooked meat
4
Q
Who does Giardia classically infect
A
children - poor hand hygiene
4
Q
symptoms of enterobius ermicularis
A
many asymptomatic perianal/vaginal itch
4
Q
what are the 2 types of taeniasis
A
taenia saginate taenia doium
5
Q
What is pathotyping mainly used for?
A
determining which virulence type it is - for E coli
5
Q
what does echinococcus granulosus cause
A
hydatid cysts
6
Q
why are type 3 secretion systems special
A
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
Q
What type of diarrhoea does EHEC cause? Which population is mostly affected?
A
- bloody diarrhoea - any age, developed coutries
8
Q
life cycle of enterobius ermicularis
A
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
Q
what are the aetiological agents of travellers’ diarrhoea
A
ETEC other bacteria viruses protozoa
9
Q
2 types of parasites
A
ectoparasites protozoal parasites
9
Q
treatment of scabies
A
- ivermentin - oral - topical scabicides (need to be over long time period) - hot wash clothes and bed linen
9
Q
what kind of helminth is strongyloides stercoralis
A
roundworm
10
Q
Main food source of Salmenella
A
raw eggs
11
Q
what is the difference between a definitive host and an intermediate host
A
definitive - parasite reaches sexual maturity in the host intermediate - development occurs but the parasite does not reach sexual maturity
12
Q
proper name for ticks
A
Ixodes holocyclus
12
Q
two main forms of protozoa
A
trophozoite - active cysts - inactive
13
Q
definition of haemorrhagic colitis
A
inflammation of the colon –> blood in the faeces (but no pus)
13
Q
life cycle of scabies
A
burrow into the epidermis –> come out to lay their eggs on the surface –> eggs hatch –> burrow into epidermis
14
Q
infection by lice is known as
A
pediculosis
14
Q
how long is taeniasis
A
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
