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Microbiology > Micro PAR 8 > Flashcards

Micro PAR 8 Flashcards

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Biology 101 flashcards
1
Q

Parasites are (eukaryotic/prokaryotic) organisms

A

EUKARYOTIC
- lack a rigid cell wall

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2
Q

There are over ____________ single celled parasites and more than ____________ helminths

A

10,000 single celled parasites
more than 50,000 helminths

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3
Q

How can parasites reproduce?

A

Sexual and asexual modes

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4
Q

Main habitat of parasites?

A

Fresh water, but some are found in soil

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5
Q

Endoparasites

A

parasites that live inside the host (ex. Ascaris lumbricoides)

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6
Q

What are the 2 categories of parasites?

A

protozoa and helminths

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7
Q

How many cells make up protozoa and helminths?

A

protozoa– UNICELLULAR
helminths– MULTICELLULAR

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8
Q

What are the 4 divisions of protozoa?

A

Amebae
Flagellates
Sporozoa
Ciliates

** classified by how they move around and life cycle

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9
Q

What are the 3 divisions of helminths?

A

nematodes (roundworms)
cestodes (tapeworms)
trematodes (flukes)

** think about these classifications as shapes

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10
Q

Amebae examples? (genus)

A

Entamoeba
Naegleria

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11
Q

Flagellate examples? (genus)

A

Giardia
Trichomonas

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12
Q

Sporozoa examples? (genus)

A

Plasmodium
Babesia
Toxoplasma

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13
Q

Ciliates example? (genus)

A

Balantidium

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14
Q

Nematodes examples (genus)

A

Ascaris
Ancylostoma

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15
Q

Cestodes examples (genus)

A

Taenia
Echinococcus

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16
Q

Trematodes examples (genus)

A

Fasciola
Schistosoma

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17
Q

How do ameba and sporozoa move?

A

ameba– move by psuedopods

sporozoa– lack a locomotive organelle

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18
Q

Protozoa size?

A

2 to more than 100 mm

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19
Q

Helminths size?

A

less than 1mm to more than a meter long

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20
Q

Routes of parasitic infections?

A
  • contact and penetration of eyes
  • contact and penetration of skin
  • vector- borne
  • inhalation
  • fecal-oral/ingestion
  • sexual contact
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21
Q

Trophozoite

A

feeding and reproducing stage that lives WITHIN the host

undergo encystment before leaving the host (usually in feces)

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22
Q

Cyst

A

INFECTIVE form that survives in the ENVIRONMENT

undergo excystment when ingested, developing into trophozoites

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23
Q

Infection of E. histolytica may spread to the….

A

liver, lungs, or brain

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24
Q

Does E. histolytic have an intermediate host?

A

NO.. mature cysts enter by ingestion, and then trophozoites leave in the feces

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25
Q

E. histolytica symptoms (acute v. chronic)

A

Acute: frequent dysentery with necrotic mucosa and abdominal pain

Chronic: recurrent episodes of dysentery with blood and mucus in the feces. Cysts are found in the stool. The organism may invade the liver, lungs, and brain and result in liver dysfunction, pneumonitis, and encephalitis.

26
Q

Trichomonas vaginalis

A

flagellate

causes genital and urinary infections

has undulating membrane

DOES NOT HAVE CYST STAGE

transmitted sexually

most common pathogenic protozoan of humans in industrialized countries

27
Q

Does trichomonas vaginalis have a cyst stage?

A

NO

28
Q

Giardia lamblia

A

worldwide distribution– most frequent protozoan intestinal disease in the US and most common water-borne disease

inadequate water purification or drinking contaminated water

infection by INGESTION of CYSTS
- decystation in the duodenum
- trophozoites colonize upper small intestine.. can attach to sub-mucosal epithelium via a SUCTION DISK
- free trophozoites encyst on the way to the colon– passed in the stool

DIAGNOSIS: finding cysts in fecal smears

man is primary host

reservoirs: beavers, pigs, monkeys

29
Q

2 main diseases caused by hemoflagellates?

A

Leishmaniasis
Trypanosomiasis (African and American forms)

30
Q

Leishmaniasis

A

L. donovani causes visceral leishmaniasis (Kala-azar, black disease)

transmitted by blood-feeding sand flies (phlebotomus)

flagellated parasites multiply and move to proboscis

in human– infect mononuclear phagocytes until the infected cell ruptures

reservoirs: dogs and rodents

31
Q

Trypanosoma cruzi

A

American trypanosomiasis (Chagas’ disease)

rural areas of central and South America

may cause sudden death from stroke or heart attack

32
Q

Trypanosoma brucei

A

African sleeping sickness

transmitted by tsetse flies (live in central africa)

33
Q

Sporozoa– definition and major diseases?

A
  • lacking cilia, flagella, or pseudopods
  • single nucleus
  • apical complex (this is how it moves)
  • sexual and asexual generations
  • life cycle includes DIFFERENT SPECIES

Major diseases: toxoplasmosis, malaria

34
Q

Toxoplasma gondii

A

causes TOXOPLASMOSIS

worldwide distribution

infection is a very serious threat in immunocompromised and pregnant women

T. gondii mostly found in cats (feces) and farm animals
- contact w infected cat feces
- consumption of raw or undercooked meat that is infected

Infection is TRANSMITTED DURING PREGNANCY (through placental connection)

DAMAGE TO THE EYE– usually invades the retina and choroid tissue. Visual acuity can be affected

35
Q

Malaria

A

caused by PLASMODIUM SPECIES (there are 4)

world’s most prevalent vector-borne disease

symptomatology of malaria depends on:
- the parasitemia
- presence of the organism in different organs
- parasite burden

incubation period– between 10-30 days

headache, lassitude, vague pains in the bones and joints, chilly sensations, fever

requires TWO HOSTS: a mosquito and a vertebrate

parasite undergoes development in liver cells prior to infecting red blood cells. In RBCs, the parasite DIGESTS HEMOGLOBIN and leaves behind indigestible portions and waste materials in the blood cell– blood cell ruptures, waste release may be associated with some of the symptoms

36
Q

What are the 4 plasmodium species that can cause malaria?

A

P. falciparum
P. vivax
P. ovale
P. malariae

37
Q

Malaria diagnosis

A

mainly based on:
- presence of fever
- patient history– always suspect malaria in feverish travelers from an endemic area

blood smears– RING SHAPED TROPHOZOITES

antibody tests or PCR

38
Q

Helminthic Parasites

A

macroscopic, multicellular, eukaryotic worms

complex life cycles

intermediate host often needed to support larval stages

3 groups– cestodes (tapeworm), nematodes (roundworm), and trematodes (flukes)

39
Q

Cestodes

A

flat, segmented intestinal parasites

NO DIGESTIVE SYSTEM (because it is a tapeworm)

all tapeworms have the same general body plan

40
Q

All tapeworms LACK a _______________ system.

A

Digestive

41
Q

Taenia

A

Cestode (tapeworm)

cattle and swine are intermediate hosts– humans living close to livestock have a greater risk

parasite attaches to intestinal epithelium causing intestinal blockage

Taenia saginata– BEEF tapeworm (6-12 feet)

Taenia solium– PORK tapeworm (12-26 feet)

SCOLEXES of T. solium and T. saginata– attachment/suction cup to intestinal wall

42
Q

Trematodes

A

aka FLUKES– flat, leaf-shaped worms

rudimentary digestive track

attach to host via ventral sucker to obtain nutrients

intermediate host: MOLLUSCS (freshwater snails or land snails)

either penetrate skin or are ingested by eating raw fish

Clinically significant trematode: Schistosoma species

initially, mild symptoms like rash or itch, infection may persist for years and damage organs such as liver or bladder

43
Q

Intestinal vs. Tissue Roundworms (nematodes)

A

INTESTINAL NEMATODES (roundworms):
- Ascaris (Giant intestinal roundworm)
- enterobius (pinworm)
- Necator/ancylostoma (hookworm)

TISSUE NEMATODES (roundworms):
- Trichinella spiralis (Trichinosis)

44
Q

Life Cycle features of Roundworms

A

parasites of almost all vertebrates

have a number of reproduction strategies

intestinal nematodes– shed their eggs into the lumen of the intestine
- eggs are eliminated in feces
- eggs are consumed in contaminated food or water

other nematodes encyst in muscle tissue and are consumed in raw or undercooked meat (trichinella spiralis)
- can sometimes see these in ham

45
Q

Trichinella spiralis

A

Trichinosis is related to the quality of pork and consumption of poorly cooked meat

direct lifecycle, meaning it completes all development stages in ONE HOST

larvae encyst in muscle

46
Q

How many bacterial species are in the oral microbiome

A

more than 700

47
Q

What are the 9 distinct communities of the oral microbiome

A

K SSS TTT PB

keratinized gingiva
sub-gingival plaque
supra-gingival plaque
saliva
tongue
tonsils
throat
palate
buccal mucosa

48
Q

In dental plaque, a complex micro environment is organized around which bacteria?

A

Corynebacteria (filamentous)

49
Q

How do corynebacteria form calculus?

A

attach firmly and grow slowly

precipitate calcium from saliva–> calculus formation

50
Q

How are individual taxa localized in biofilm?

A

By their functional niche

51
Q

Where does streptococcus grow in the biofilm?

A

Strep grows near the tips of the biofilm

uses oxygen, which creates anoxia near the core

52
Q

What bacterial metabolism can lower blood pressure?

A

nitrate metabolism

53
Q

What bacterial substance can help prevent obesity?

A

Butyrate– made by oral and gut microbiomes

54
Q

“The periodontal disease communities are organized around integrated pathways for the metabolism of…”

A
  • butyrate
  • tetrahydrofolate
  • histidine degradation
  • nucleotide biosynthesis
55
Q

AHL

A

N-acyl homoserine lactone (quorum sensing signal)

released by the biofilm in response to cells and soluble factors from the host (like what neutrophils release when they degranulate)

56
Q

Neutrophil actions on biofilm?

A

degranulate, phagocytose bacteria, release extracellular chromatin

57
Q

______% of American Adults have periodontitis

A

47.2%

most is moderate periodontitis, but there is also mild and severe periodontitis present throughout the population

58
Q

Normal/Healthy Oral Microbiome

A

survive daily physical and chemical perturbations from food intake and personal hygiene– able to form a long-term stable microbiome

help prevent dysbiosis

59
Q

Tolerance Induction Hypothesis

A
  1. pregnancy causes spontaneous bleeding of the gums (pregnancy gingivitis)
  2. bacteria get into the blood stream and are transferred to the placenta
  3. oral bacteria of mother get trapped in the placental tissue
  4. Fetal APCs “scope out” alloantigen information and take it back to the fetal peripheral lymphoid organs
  5. fetal regulatory T cells (Treg) that recognize the mothers microbiome as “safe” are generated in the fetal lymphoid tissue

EVIDENCE
- microbes are present in placenta, umbilical cord blood, and amniotic fluid in full-term pregnancies without overt infection
- placental microbiome does not resemble vaginal or gut microbiomes– it is most similar to the normal oral microbe

60
Q

Far-Reaching Consequences of Periodontal disease

A

Systemic inflammation (TNF, IL-1b, IL-6)
- causes liver to release CRP, fibrinogen, and serum amyloid A

Systemic bacterial dissemination
- promotes atherosclerosis (can be predisposing factor for heart disease

Swallowing bacteria
- lead to dysbiosis in the gut –> endotoxaemia–> systemic inflammation contribution

Inflammation-induced pregnancy complications can happen when all of the above problems are stacked

61
Q

Periodontal disease and atherosclerosis

A

PD occurs in a large number of heart disease patients

potential reason: pro inflammatory systemic response

oral microbes can be identified in the blood and atherosclerotic plaque in blood vessels

62
Q

Citrullination

A

unusual AAs not present in normal transcription are introduced… caused by exogenous things like tobacco

has a role in arthritis (cyclic citrullinated peptide, CCP)

reaction is also called deimination
- arginine residue is converted to a citrulline residue by PAD4 in the presence of water.. rxn releases ammonia

Hypercitrullination can be associated with autoimmunity in rheumatoid arthritis– autoantibodies against citrullinated proteins are created (causes neutrophils to migrate and an immune complex forms)

Patients with periodontal disease have MORE CITRULLINATED PROTEINS

Microbiology (2 decks)

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