Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

1st Year - Gastroenterology > Microbiology 1 - Gastroenteritis and food poisoning > Flashcards

Microbiology 1 - Gastroenteritis and food poisoning Flashcards

1
Q

What host factors affect your risk of gastrointestinal infection? (5)

A

Age (very young and elderly)Decreased gastric acid secretionDecreased gut motilityInfluence of colonic microfloraIntestinal immunity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What bacterias seen in the UK cause Gastrointestinal infections? (8)

A

Campylobacter coli/ jejuniSalmonella entericaE coli O157Shigella sonneiStaph aureus/ Clostridium perfingens/ Bacillus cereusC difficile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What viruses seen in the UK cause gastrointestinal infections? (2)

A

NorovirusRotavirus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What parasites seen in the UK cause gastrointestinal infections? (2)

A

Cryptosporidium spGiardia lamblia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What bacterias, usually imported from abroad, case gastrointestinal infections?

A

Vibrio cholerae/ parahaemolyticusSalmonella typhi/ paratyphiAeromonas sp.Shigella dysenteriae/ flexneri/ boydii

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What parasite, usually imported from abroad, can cause GI infections?

A

Entamoeba histolytica

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is diarrhoea?

A

3 or more loose stools in 24 hours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the source/ reservoir of infection?

A

The original source of the infection e.g. animal gut, another human’s gut, etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the vehicle of infection?

A

The means by which the infection is transmitted from one person to another (e.g. contaminated food/ water)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the source and vehicle of infection of E. coli O157

A

Source = cattle GI tract Vehicle of infection = undercooked hamburger

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What shape is camplobacter (C. jejune, C. coli)?

A

Curved gram negative bacilus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the commonest cause bacterial GI infection in the UK?

A

Campylobacter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Incubation period of campylobacter?

A

3-10 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does campylobacter make you unwell?

A

Causes inflammation of the colon and rectum leading to bloody diarrhoeaCan invade and occasionally get into bloodstream (patients get systemically unwell with flu like symptoms)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the main source/ vehicle of infection of campylobacter?

A

Undercooked poultry + other farm animals, water and unpasteurised milk (person to person spread is rare - outbreaks usually because consumed the same chicken)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Symptoms of campylobacter?

A

Abdo pain Diarrhoea =/- blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Management of campylobacter?

A

Usually self limiting but give ERYTHROMYCIN or CIPROFLOXACIN for 5 days if patient develops systemic illness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does “enteric” in Salmonella enterica mean?

A

It is the agreed species name for all food poisoning i.e. non-typhoidal salmonella (often still called by species name e.g. S. enteritiditis, S. typhimurium, etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the incubation period for Salmonella enterica?

A

12 - 48 hours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the mechanism of action of Salmonella enterica?

A

Causes inflammation of the ileum and colon - multiply in gut and cause mucosal damage, decreased mucosal damage and increased fluid excretionCan invade and occasionally get into bloodstream

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the source/ vehicle of infection of salmonella enterica?

A

Undercooked poultry + other farm animals (much less common since immunisation of poultry against Salmonella spp.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Symptoms of salmonella enterica?

A

Abdo painDiarrhoea (occasionally bloody)Vomiting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Management of salmonella?

A

Usually ciprofloxacin for 5 days if patient at risk of or develops systemic illness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What type of Shigella is seen in the UK?

A

Shigella sonnei (most benign type) - outbreaks occur every few years amongst cohorts of vulnerable children

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Incubation period for Shigella sonnei?

A

1-9 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Mechanism of action of Shigella sonnei?

A

Invades intestinal mucosa causing severe inflammation, but does not invade further (never seen in blood cultures)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is seen in the stools of a patient with Shigella?

A

Blood and pus cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Source/ vehicle of infection of Shigella?

A

Human only infectionOften spread person- person amongst young children in schools, etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Symptoms of shigella Sonnei?

A

Abdo painDiarrhoea (occasionally blood)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Management of Shigella sonnei?

A

Usually self-limiting - symptomatic treatment only Other species of Shigella (dysenteriae, etc.) acquired abroad, usually require Ciprofloxacin due to more severe infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What strain of E coli produces a toxin that damages red blood cells and the kidneys?

A

The O157:H7 strain (and a few other serotypes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What type of toxin does E coli O157 produce and what does this do?

A

verotoxin (VTEC)Damages red cells and the kidney, causing haemolytic-uraemic syndrome (HUS)(increased blood urea, red cell haemolysis and thrombocytopenia)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Who are most at risk of developing HUS?

A

Children

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is the source/ vehicle of infection of E coli O157?

A

Carried as part of the normal gut flora in cattleBeef becomes contained on the outside at slaughter = increased risk from minced meat and hamburgers than from a steakNursery/ school visits to farmPrivate (untreated) water supplies = run off water from fieldsLow infecting dose, so person-person spread causes 2y cases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Symptoms of E coli O157?

A

Abdo painBloody diarrhoea is common

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Management of E coli O157?

A

Symptomatic and supportive treatment onlyAntibiotics contraindicated as may increase release of toxinCheck bloods for HUS 1 week after onset of symptoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What does verotoxin do?

A

Binds to receptors found on renal cells, RBC and othersInhibits protein synthesisCauses cell death

38
Q

Clinical presentation of HUS?

A

Abdo painFeverPallorPetechiaeOliguria (decreased urine production)Bloody diarrhoea in 90% of casesMostly in under 16s

39
Q

When is the peak presentation of HYS?

A

7-10 days after onset of diarrhoea

40
Q

What does blood tests show which indicates HUS? (5)

A

High white cellsLow plateletsLow HbRed cell fragmentsLactate dehydrogenase (increased 1.5 times normal)

41
Q

Appearance of Salmonella, Shigella and E coli O157 on gram film?What is used to differentiate between these?

A

Gram negative bacilli Biochemical tests, then serological tests

42
Q

What bacteria causes typhoid and paratyphoid fever?

A

Salmonella typhi/ salmonella paratyphi A and B

43
Q

What are the symptoms of typhoid/ paratyphoid fever?

A

Initially a febrile illness (bacteria circulating in bloodstream) causing headache, flu-like symptoms followed by diarrhoea 2 weeks later

44
Q

When is typhoid/ paratyphoid seen in the UK?

A

When it has been imported from abroad

45
Q

Incubation period of typhoid/ paratyphoid fever?

A

14 - 21 days

46
Q

Mechanism of action of typhoid/ paratyphoid?

A

Organism invades from gut lame -> lymphatic system -> bloodstream -> reticuloendothelial system and gall bladder -> gut lumen and invades Peyer’s patches

47
Q

In chronic carriers of typhoid/ parathyroid, where does the bacteria reside?

A

The gallbladder

48
Q

What can happen during the bacteraemic phase of typhoid/ paratyphoid?

A

Distant sites can become infected e.g. ostemyelitis

49
Q

Source of salmonella typhi/ paratyphi?

A

Human only infectionSpread person-person or from drinking contaminated water/ eating contaminated food/ poor sanitation (different from entericas which are associated with animals)

50
Q

Symptoms of typhoid/ paratyphoid?

A

FeverRash on abdomen (“rose spots”)Diarrhoea

51
Q

Management of Typhoid/ paratyphoid?

A

Antibiotics are required, choice depends on sensitivities. Resistance to ciprofloxacin

52
Q

What causes cholera?

A

Vibrio cholerae (“the comma bacillus”)

53
Q

What is the appearance of Vibrio cholera?

A

Small curved gram negative baciluus

54
Q

Where are outbreaks of cholera common?

A

In disaster/ war stricken situations

55
Q

Incubation period of cholera?

A

1-9 days

56
Q

Mechanism of action of cholera?

A

Organism produces an exotoxin that causes active outpouring of fluid from cells of small intestine resulting in severe watery diarrhoea

57
Q

Source/ vehicle of infection of Vibrio cholerae

A

Human only infection - spread person-person or from drinking contaminated water/ poor sanitation

58
Q

Symptoms of cholera?

A

Watery diarrhoea “rice water stools” causing rapid dehydration

59
Q

Management of cholera?

A

Fluid and electrolyte replacement Antibiotics NOT indicated

60
Q

What causes GI infections associated with ingestion of pre-formed toxin? (3)

A

Staph aureusClostridium perfingensBacillus cereus

61
Q

What is an enterotoxin?

A

A protein exotoxin released that targets the intestine

62
Q

What is the typical scenario where Staph aureus is passed on through food?

A

Bakery worker with infected finger touches cream cakeStaph aureus multiplies producing enterotoxin (exotoxin)Customer ingests enterotoxin

63
Q

What does ingestion of staph aureus enterotoxin cause?

A

Acts directly on vagus nerve and vomiting centre inducing vomiting within 1 - 2 hours

64
Q

What is the appearance of clostridium perfingens?

A

Large gram positive anaerobic bacillus

65
Q

Where is clostridium profanens normally found?

A

Part of the normal gut flora in humans and animals

66
Q

How does clostridium perfringens cause infection?

A

Spores survive cooking, then turn into vegetative organism some strains of which produce enterotoxin (an exotoxin)

67
Q

What is clostridium perfringens infection associated with?

A

Inadequately refrigerated re-heated meat gravy

68
Q

What is the appearance of bacillus cereus?

A

Large gram positive aerobic bacillus

69
Q

How can a patient contract bacillus cereus?

A

Exotoxin can be ingested as pre-formed toxin in foodOrganism can multiply in intestine, producing toxin that is absorbed from the gutSpores survive cooking, then turn into vegetative organisms that produce toxin

70
Q

What is bacillus cereus infection associated with?

A

Contaminated inadequately refrigerated reheated rice

71
Q

What 2 bacterias have short incubation periods? (1-6 hours)

A

Staph aureus

72
Q

What 2 bacterias have a medium incubation period? (12-48hours)?

A

SalmonellaCl perfrigens

73
Q

What 2 bacteria have a long incubation period? (2-14 days)

A

CampylobacterE coli O157

74
Q

Cryptosporidium and Giardia lamblia are both protozoal infections - true/ false?

A

True

75
Q

Mechanism of action of cryptosporidium?

A

Infection occurs when cysts are ingested which “hatch” into trophozoites that invade the cells of the small intestine

76
Q

Source/ vehicle of infection of cryptosporidium?

A

Domestic animals, especially calvesPerson-person spreadOutbreaks associated with contaminated water supplies and swimming pools (cysts resistant to chlorine)

77
Q

Symptoms of cryptosporidium?

A

DiarrhoeaParticularly severe in HIV pos patients

78
Q

Management of Cryptosporidium?

A

Symptomatic treatment only

79
Q

What type of stain can be used to identify cryptosporidium cysts?

A

Ziehl-Neelson stain (pink cysts against blue background)

80
Q

Mechanism of action of Giardia lamblia?

A

Infection occurs when cysts are ingested which “hatch” into trophozoites that invade the cells of the upper small intestine

81
Q

Source/ vehicle of infection of Giardia lamblia?

A

Human only infection?person to person spreadOutbreaks associated with contaminated water supplies

82
Q

Symptoms of Giardia lamblia?

A

DiarrhoeaMalabsorption syndromeAnorexiaAbdominal painFlatulence

83
Q

Management of Giardia lamblia?

A

Oral metronidazole

84
Q

What is the more commonly used name for Enterobius vermicularis?

A

Threadworms

85
Q

Pathogenesis of thread worms?

A

Ova (egg) ingested -> hatch in intestine and live in caecum and colon -> adult females come out on to perianal skin at night and lay ova -> ova cause perianal itch -> child scratches bottom -> puts fingers in mouth

86
Q

Source/ vehicle of transport of enterobius vermicularis?

A

Human only infectionPerson-person spread (poor hygiene)

87
Q

Symptoms of Enterobius vermicularis?

A

Perianal itchWorms seen in stool

88
Q

What is the treatment for Enterobius vermicularis?

A

Oral mebendazole (often have to treat all members of family at once)

89
Q

What must be done if blood is seen in the patients stool?

A

Stool must be sent to ref lab for E coli verotoxin detection

90
Q

When sending a stool sample to the lab for testing, what must you tell the lab if the patient has been abroad?

A

Where they were

1st Year - Gastroenterology (37 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions