Brainscape's Knowledge GenomeTM

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


See full index

Microbiology > MIcrobiology Exam 2 - Parasitology and Mycology > Flashcards

MIcrobiology Exam 2 - Parasitology and Mycology Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

Parasite definition

A

an organism living in or on another and benefiting at the expense of the other (technically includes all flora found in and on us

  • generally reserved for eukaryotic organisms
  • includes broad range of animals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

parasites examples

A 
malaria
giardiasis
ascariasis
toxocariasis
head lice
acanthamoeba
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

malaria - what it means, bug involved and what carries (transmits) it

A

“bad air”
blood parasites of the protozoan genus Plasmodium
Anopheles mosquito

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

what species infect humans with malaria?

A 
4 of them:
P. falciparum
P. vivax
P. ovale
P. malariae
*don't have to list these from memory, but should be able to recognize for exam
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

which malaria-infecting species is predominant in endemic regions?

A

P. falciparum

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

malaria epidemiology and transmission

A

epidemiology:
350-500 mill infections/yr w/ high rate of mortality (about 1 mill deaths annually, mostly young children)
transmitted by the Anopheles mosquito (vector)
geographic distribution correlates to vector (mostly tropical areas)

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

1st stage of malaria

A

human liver stage (exo-erythrocytic cycle, is OUTSIDE the blood)
sporozoites from mosquito infect liver cell -> mature into schizonts (many more progeny are made) ->schizont ruptures and releases merozoites -> they enter the next stage

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

2nd stage of malaria

A

human blood stage (erythrocytic cycle)
undergo asexual replication in erythrocytes and infect RBC’s -> immature trophozoite (ring stage) -> either goes back into schizont stage w/ rupture OR matures and -> becomes gametocytes

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

3rd stage of malaria

A

mosquito stages
gametocytes (male=micro, female=macro) ingested by Anopheles mosquito during a blood meal -> sporogonic cycle (parasites multiply) -> micros penetrate macros, generate a zygote -> zygotes become motile and elongated -> invade the midgut wall of mosquito and develop into oocysts -> oocysts grow, rupture, release sporozoites -> they go to mosquito’s salivary glands -> mosquito bites human

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

how many hosts does the parasite life cycle involve?

A

2 (human and mosquito)

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

malaria clinical findings

A

uncomplicated:
-fever, chills, sweats, headache, nausea, vomiting, myalgia, weakness
-can get involvement of spleen, kidneys, lungs, NS
severe (particularly P. falciparum):
-cerbral malaria, severe anemia, hemoglobinuria, pulmonary edema or ARDS, reduced platelets, cardio collapse and shock
-relapses seen w/ P. vivax or P. ovale (will get dormant pop.’s called “hypnozoites, which can then lead to a relapse)

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

dx and tx for malaria

A

dx: microscopy (look for schizonts in culture)
tx: variety of compounds
-> chloroquine and quinine (blocks heme detoxification)
• Resistance levels are high
– Vaccine development currently unsuccessful

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

giardiasis - what is it and where found

A

Protozoan flagellate Giardia intestinalis (the one that infects humans)
• Worldwide distribution, common in United States

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

giardiasis transmission

A

contaminated water, food or hands/fomites with infective cysts (trophozoites are also passed in stool but do not survive the environment)

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

giardiasis clinical findings

A

– Incubation 1 to 14 days
– Self limiting infection typically 1 to 3 weeks
– Diarrhea, abdominal pain, bloating, nausea, vomiting
• Can become chronic

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

dx and tx for giardiasis

A

Diagnosed by microscopy
• Cysts or trophozoites in feces
– Treated with metronidazole and tinidazole

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

toxocara - what is it and where found

A

Nematode Toxocara canis or T. cati
– Dog or cat roundworm
• Worldwide distribution

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

toxocara transmission

A

we get exposed to infected animal’s feces in environment, gets into us, but parasite gets “lost” in our body b/c not in its home

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

toxocara clinical findings

A

Many asymptomatic infections with +ve serology
– Visceral larval migrans (VLM)
• Mostly preschool children
• Larva invade liver, heart, lungs, brain, muscle
• Fever, anorexia, weight loss, cough, wheezing, rashes, hepatosplenomegaly, hypereosinophilia
• Death (rare) due to heart/lung/neurological involvement
– Ocular larval migrans
• Opthalmological lesions and damage to eye
• Risk of misdiagnosis as retinoblastoma

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

toxocara dx and tx

A

Diagnoses by history, symptoms and antibodies

– Treatment with albendazole (targets microtubules) and anti-inflammatories

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

ascariasis - what and where found

A

Nematode Ascarislumbricoides
• Worldwide distribution
– Most common helminthic infection
– Rural areas of southeastern United States

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

ascariasis transmission

A

feces, hand to mouth, poor personal hygiene

-can migrate viscerally to the lungs; you cough them up and then swallow them -> back down the intestinal tract (yuck).

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

ascariasis clinical findings

A

Usually no acute symptoms
– High body burden can cause abdominal pain due to obstruction
– Migrating adults can block biliary track or be expelled orally
– Can develop pulmonary symptoms during larval migration (Loeffler’s syndrome)

24
Q

ascariasis dx and tx

A

– Diagnoses by microscopy of stool

– Effective drug treatment (ex. albendazole)

25
Q

head lice - what and where

A

• Pediculosis
• Pediculus humanus capitis – a human ectoparasite
found everywhere?

26
Q

lice transmission

A

Some transmission via fomites

27
Q

lice clinical findings

A

Majority of infestation are asymptomatic
– Symptoms include “tickling feeling of something
moving in the hair”, itching (an allergic reaction to louse saliva), and irritability
• Secondary bacterial infection can be a complication

28
Q

fungi types

A

Molds, yeast and fleshy fungi

• 150 species are pathogenic to humans

29
Q

fungi structure

A

Similar to other eukaryotes
– Nuclei, mitochondria, 80S ribosome, etc.Thick cell walls comprised of glucans or chitin (know that)
– Unlike bacterial bacterial peptidoglycan
• Membranes contain ergosterol and zymosterol
– Unlike us (we have cholesterol)

30
Q

fungi reproduction

A

Reproduce by asexual budding or sexual spores

• Play an important role in turnover of nutrients in the environment

31
Q

yeast - what and reproduction

A

Unicellular fungi
– larger than most bacteria
• Reproduce primarily by budding
– fungi imperfecti

32
Q

medically relevant species of fungi

A

– Exogenous - Cryptococcus neoformans,
Aspergillus
– Endogenous - Candida

33
Q

candida - what

A

Normal flora of the oral cavity, gut, vagina
and occasionally the skin
– Candida albicans, C. glabrata, and others
• Yeast phase referred to as blastospores
– Single, oval buds - 5µm
• Can form elongated filaments
– pseudohyphae

34
Q

candida control and defense

A

Generally, Candida exists as a normal
component of the oral flora BUT can become an opportunistic pathogen
• Kept in check by …
– Physical barriers, saliva, microbial competition
and phagocytosis
– sIgA can restrict surface adhesion

35
Q

when candida goes bad, what can happen?

A

Vulvovaginal candidiasis (VVC)
– “yeast infection”
– Overgrowth in response to hormonal changes, pH change, change
in normal flora
– Itching/burning sensation
– Readily diagnosed with microscopy
• Invasive candidiasis
– Candidemia and disseminated infection
– *Neonates, surgical patients, immunosuppressed
– Fever and chills that are unresponsive to antibiotics
– *(systemic) involvement of kidney, liver, bone, muscle, joints, spleen or eyes
– *Death due to organ failure in 50% of untreated cases
– Diagnosed by microscopy
In the oral cavity you get a superficial
mycoses
• Oropharyngeal candidiasis (OPC)
– proliferation triggering inflammation
– ex. white pseudomembrane on buccal mucosa
• Pseudomembranous candidiasis
– Thrush
– No penetration of epithelium
– Easily wiped off revealing raw, inflamed tissue
underneath

36
Q

factors predisposing to pseudomembranous candidiasis (thrush)

A 
chronic local irritants
ill-fitting appliances
inadequate care of appliances
disturbed oral ecology or marked changes in the oral microbial flora by antibiotics, corticosteroids, xerostomia
dietary factors
immunological and endocrine disorders (e.g. diabetes mellitus)
malignant and chronic diseases (can be an indicator of a more severe systemic infection - want to find out the cause)
severe blood dyscrasias
radiation to the head and neck
abnormal nutrition
age (very young or very old)
hospitalization
oral epithelial dysplasia
heavy smoking
37
Q

agar used to culture candidiasis

A

Sabouraud agar

**this has been on boards

38
Q

other types of candida and associated lesions

A 
Oral mucosa 
– Erythematous candidiasis
– Hyperplastic candidiasis
(these 2 are a little different, he didn't know how)
• Associated lesions 
– Denture stomatitis
– Median rhomboid glossitis (one of many causes?) 
– Angular cheilitis
39
Q

tx for candidiasis

A 
• Polyenes
– ex. Nystatin, Amphotericin B 
– Binds ergosterols in membrane causing leakage 
• Azoles 
– ex. Fluconazole, 
Miconazole
– Inhibits ergosterol synthesis 
– **resistance high in C. 
glabrata** -> KNOW
• Echinocandin B 
– Interferes with glucan synthesis (targets glucan of cell walls instead of sterols)
40
Q

cryptococcosis - what, transmission, epidemiology

A

Cryptococcus neoformans
– Normal flora in birds (pigeons) -> NOT normal for us (is exogenous pathogen)
– Transmitted by inhalation
Epidemiology:
- High mortality (12% in US, 75-90% in Africa)

41
Q

cryptococcosis symptoms

A

Symptoms similar to pneumonia

– Can lead to fungaemia, meningoencephalitis

42
Q

cryptococcosis tx

A

Treated with fluconazole and amphotericin

43
Q

aspergillosis - what

A

Aspergillusspp. (A. fumigatus, A. flavus, etc.)

– Found in soil, plants, decaying organic matter

44
Q

aspergillosis types with symptoms

A

Allergic bronchopulmonary aspergillosis (ABPA)
– Wheezing/coughing
• Aspergilloma (fungus ball) in lung or other organs
• Invasive aspergillosis
– Fever, chest pain, cough, shortness of breath
– Dissemination throughout organs, including brain
– Treated with voriconazole (cytochrome target)

45
Q

dermatophytes - what

A

Tinea or ringworm
• Caused by many species of fungi
– Trichophyton rubrum, T. tonsurans
– Microsporum canus

46
Q

dermatophytes transmission

A

Spread by contact

47
Q

dermatophytes types

A 
Appears as infections on the skin, hair, or nails 
– Tinea barbae – beard 
– Tinea corporis – body 
– Tinea pedis – feet (athelete’s foot) 
– Tinea cruris – groin (jock itch) 
– Tinea capitis – scalp
48
Q

dermatophytes clinical findings

A

Symptoms:
– Appear 4-14 days post-exposure
– Itchy, red, raised, scaly patches that may blister and ooze
– Sharply-defined edges, often redder than adjacent tissue, and may be “ring-like”
– Balding patches in hair
– Thick, discolored and perhaps crumbly nails

49
Q

dx and tx

A

Diagnosed by KOH test, biopsy and culture
• Treated with topicals (miconazole, clotrimazole, etc.) or systemically (ketoconazole)
• Controlled with good hygiene

50
Q

In what stage of malaria do you see clinical manifestations of the disease?

A

The blood stage

51
Q

What are the 2 kinds of larva in toxocariasis?

A

Visceral larval migrans (affects liver, lungs, heart, brain, muscles) - death in rare cases
Ocular larval migrans (lesions/damage to eye, often misdiagnosed as retinoblastoma)

52
Q

Most common helminthic infection

A

Ascariasis

53
Q

What is albendazole effective at treating?

A

Infections due to “wormy” stuff; i.e. Toxocariasis and Ascariasis

54
Q

Other oral types of candidiasis besides pseudomembranous

A

“Eh” (b/c Jardine didn’t know much about)
Erythmatous candidiasis
Hyperplastic candidiasis

55
Q

In what yeast is resistance to azoles (drugs) high?

A

C. glabrata

Microbiology (1 decks)

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