Chap8- General Principles Flashcards Preview

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Flashcards in Chap8- General Principles Deck (192)
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1
Q

What is a prion

A

abnormally folded host protein PrP

2
Q

What diseases are caused by prions

A

kuru- spongiform encephalopathie
Creutzfeldt-Jakob disease
Bovine spongiform encephalopathy (mad cow)
variant CJD- from infected bovine

3
Q

How do prions cause disease

A

undergo a conformational change that is resistant to proteases
the resitance PrP then convert normal PrPs

4
Q

how can CJD be transmitted

A

iatrogenically, surgery, organ transplant, blood transfusion

5
Q

What is a virus

A

obligate intracell organism that need host machinery

have genome in a capsid and sometimes encased in lipid membrane

6
Q

Under a light microscope how can you identify a virsu

A

inclusion bodies

7
Q

What are the common viruses with inclusion bodies

A

cytomegalovirus
herpes
smallpox and rabies

8
Q

what is a latent infection

A

nonreplicating form of a virus

9
Q

What are bacteria

A

prokaryotes, do not have membrane bound organelles
gram + have single outside layer
gram - have 2 thin lipid bilayers

10
Q

what are pili on bacteria used for

A

attach to host cells or ECM

11
Q

Describe staining of Staph aureus

A

gram + cocci in clusters- degenerating neutrophils

12
Q

describe staining of Strep. pneumoniae

A

gram + elongated cocci in pairs and short chains

13
Q

describe staining of clostridia species

A

gram + and -

although tru gram +

14
Q

What are common gram - rod bacteria

A

E coli, klebsiella pneumoniae

15
Q

What is the most common seem gram - diplococci

A

neisseria gonorrhea

16
Q

What bacteria causes lyme disease meningoencephalitis

A

spirochete Borrelia burgdorferi

17
Q

What bacterium contributes to dental plaque

A

strep mutans

18
Q

what are facultative intracellular bacteria

A

can survive and replicate outside or inside host

19
Q

what are obligate intracellular bacteria

A

need the host to survive

20
Q

are chlamydia and Ricketssia, obligate or facultative

A

obligate because rely on ATP for energy source

21
Q

What is the most frequent infection that leads to female sterility

A

chlamydia trachomatis

scarring fallopian tubes and blindness via conjunctivitis

22
Q

How does Ricketssia cause damage

A

injures endothelial cells and causes hemorrhagic vasculitis and sometimes CNS

23
Q

Rocky Mountain spotted fever and epidemic typhus are examples of what

A

Ricketssia family

24
Q

What bacteria are the tiniest free living organisms known

A

mycoplasma organisms

25
Q

What are fungi

A

eukaryotes with thick, chitin cell walls with ergosterol-containing membranes

26
Q

What are the 2 shapes of fungi

A

rounded yeast cells or slender filamentous hyphae

27
Q

describe the types of hyphae fungi charactersitics

A

septate(with cell walls) or aseptate

28
Q

Describe fungi thermal dimorphism

A

hyphal forms at room temp then yeast at body temp

29
Q

What are conidia

A

asexual spores from fungi

30
Q

Describe the superficial fungi

A

dematophytes that are referred to as tinea

31
Q

what are examples of fungal species that invade subcut

A

sporothrichosis

tropical mycoses

32
Q

Describe the clinical features of oportunistic infections in immunocompromised patients

A

tissue necrosis, hemorrhage and vascular occlusion

33
Q

What opportunistic infection is seen in AIDS patients

A

Pneumocystis jiroveci

34
Q

What are protozoa

A

single celled mobile eukaryotes

35
Q

What is the protozoa in RBC? in Macrophages?

A

RBC plasmodium

macrophages leishmania

36
Q

What are the most common intestinal protozoans?

What are their 2 forms

A

entamoeba histolytica
giardia lamblia
motile trophozoites that attach to intestinal epithelial wall
immobile cysts that are R to stomach acids and infectious when ingested

37
Q

What type of organism is trichomonas vaginalis

A

protozoa

38
Q

How are the blood borne protozoans trasnmitted

A

insect vectors

39
Q

How is toxoplasma gondii acquired

A

contact with oocyst shedding kittens or by eating cyst-ridden undercooked meat

40
Q

What are helminthes

A

highly differentiated multicellular organisms with complex life cycles

41
Q

What are the differences of ascaris, toxocara and echinococcus species of helminthes

A

ascaris lumbricoides is adult
toxocara canis is immature
echinococcus species are asexual larval forms

42
Q

is 10 hookworms a problem

A

rarely but 100 can cause anemia

43
Q

What is the mode of disease caused by schistsomiasis

A

disease is from inflammatory response to eggs or larvae rather than to the adults

44
Q

What are ectoparasites

A

insects: lice, bedbugs, fleas or arachnids: mites, ticks and spiders

45
Q

What is typically found at the site of a ectoparasite bite

A

lymphocytes, macrophages, eosinphils

46
Q

What bacteria can be seen in H&E stains

A

the inclusion body forming bacteria, Cadida and mucor fungi, most protozoans and all helminthes

47
Q

Where are organisms best visualized

A

edge of a lesion not the center

48
Q

Acid Fast staining is used to visualize what

A

mycobacteria and nocardiae

49
Q

silver stains are used to visualize what

A

fungi, legionella and penumocystis

50
Q

periodic acid shiff is used to visualize what

A

fungi and amebae

51
Q

mucicarmine stain is used to visualize what

A

cryptococcie

52
Q

giemsa stain is used to visualize what

A

campylobacteria and leishmaniae, malaria parasites

53
Q

What marker is used Dx shortly after onset symptoms

A

IgM Ab

54
Q

What rise in titer is considered Dx

A

4X

55
Q

what is used for Dx of gonorrhea and chlamydia, TB and herpes encephalitis

A

PCR

56
Q

in detecting herpes is a PCR of CSF more sensitive or a viral culture of CSF

A

the PCR

57
Q

For chalmydia do you want normal culture or necleic acid tests as well

A

nucleic acid detects 10-30% more

58
Q

What does ebola virus cause

A

epidemic ebola hemorrhagic feer

59
Q

what does hantaan virus cause

A

hemorrhagic fever with renal syndrome

60
Q

what does campylobacter jejuni cause

A

enteritis

61
Q

what does HTLV-1 cause

A

T cell lymphoma or leukemia, HTLV- assoc myelopathy

62
Q

What does S.aureus cause

A

Toxic shock syndrome

63
Q

what does E coli cause

A

hemorrhagic colitis, hemolytic-uremic syndrome

64
Q

What does Borrrelia burgdorferi cause

A

lyme disease

65
Q

What does helicobacter pylori cause

A

gastric ulcers

66
Q

what does Hep E cause

A

enterically transmitted hepatitis

67
Q

what does Hep C cause

A

Hep C

68
Q

When was vibrio cholerae detected

A

1992 as new choler straing

69
Q

what causes cat scratch disease

A

bartonella henselae

70
Q

what is kaposi sarcoma assoc with

A

AIDs patients HHV-8

71
Q

When was west nile virus identified

A

1999

72
Q

When was SARS identified and what is its manifestation

A

2003

coronavirus causing severe acute respiratory syndrome

73
Q

What species have acquired antibiotic resistance

A

Mycobacterium tuberculosis, Neisseria gonorrhoeae, S.aureus, Enterococcus faecium

74
Q

What are catergory A bioterism organisms

A
Anthrax- bacillus anthracis
Botulism- Clostridium botulinum toxin
Plague- yersinia pestis
smallpox- variolla major virus
tularemia
viral hemorrhagic fevers
75
Q

What are catergory B bioterism organisms

A
Brucellosis, epsilon toxin-Clos perfringens
food safety(salmoneela, e coli)
glanders
meliodosis
staph enterotoxin B
Ricin toxin (castor beans)
typhus fever
viral encephalitis
76
Q

What are category C bioterism organisms

A

emerging infectious disease threats such as Nipah and Hantavirus

77
Q

What is common in the cat A bioterism organisms

A

need small dosages to cause large infection

aerosolize

78
Q

What are signs of smallpox infection

A

7-17 days have high fever, HA and backache

then rash on mouth and pharynx, face and forearms that continues to spread

79
Q

What components of skin are part of our immunity

A

dense keratinized outer layer with pH 5.5 and the FA inhibit microorganism growth

80
Q

What organism can enter unbroken skin and how

A

Schistosoma larvae from freshwater snails via collagenase and elastases

81
Q

What are the GI defenses against microorganisms

A
acidic gastric secretions
layer of viscous mucus
pancreatic enzymes and bile dtergents
mucosal defensins
flora
secreted IgA Ab
82
Q

why are shigella and giardia cysts so relentless on the GI track

A

resistant to gastric acid

83
Q

What make the IgA Ab in GI

A

MALT mucous associated lymphoid tissues covered by M cells that transport the Ag

84
Q

What weakens our GI system

A

low gastric acidity by Ab that alter normal flora

Resistant nonenveloped viruses

85
Q

how do staphylococcal strains cause GI disease without bacterial multiplication

A

powerful enterotoxins on the food

86
Q

What is the mech of V cholerae and E coli in the GI

A

release exotoxins that cause gut to secrete large volumes of fluid

87
Q

what is the mech of shigella, salmonella and campylobacter in the gut

A

invade and damage intestinal mucosa and lamina propria causing ulceration, inflammation and hermorrhage

88
Q

What is the mech of salmonella typhi in GI

A

enters through peyer patches and mesenteric lymph into blood stream resulting in systemic infection

89
Q

What tapeworm clinically apppears to cause pernicious anemia

A

Diphyllobothrium datum from depleting host of B12

90
Q

How do respiratory pathogens escape innate mech

A

attach to epithelial cells in lower respiratory tract and pharynx
or impair ciliary activity

91
Q

qHow do influenza viruses attack respiratory system

A

have hemagglutinin proteins that project from surface protein and then neuroaminidase which cleave it and allow rvirus to enter host cell

92
Q

what pathogens inhibit ciliary mech of airways

A

haemophilus influenza and Bordetella pertussis

93
Q

what lung infections are chemotherapy patients most at risk for

A

Aspergillus species

94
Q

Why are women more prone to urinary infections

A

shorter urethra

95
Q

what happens if UTI retrograde to the bladder

A

can go further anc cause chronic polynephritis

96
Q

what is the initial microbial spread

A

tissue planes of least resistance and sites drained by lymph

97
Q

What pathogens can leukocytes carry

A

herpes, HIV, mycobacteria and leishmania and toxoplasma

98
Q

What pathogens are carried on RBC

A

viruses- colorado tick fever virus

parasites- plasmodium and babesia

99
Q

what are the manifestations os serious pathogenic insult

A

fever, low BP, sepsis

100
Q

poliovirus enters via intestine but spread where

A

kills motor neurons

101
Q

shistosoma mansoni parasites penetrate skin but damage ehere

A

localize in blood and mesentery damaging liver and intestine

102
Q

Where does varicella zoster virus hide latently until activated

A

in the DRG then on activation travels on nerves to cause shingles

103
Q

when can there be transmission of treponemas in utero

A

late second trimester and causes severe fetal osetochondritis and periostitis

104
Q

What infections can occur through maternal milk

A

CMV, HBV, Human T cell leukemia virus 1

105
Q

What pathogens are usually spread via respiration

A

viruses and bacteria

106
Q

what pathogens are spread fecal-orally

A

viruses helminths

107
Q

What are some water-borne viruses

A

Hep A and E
poliovirus
rotavirus

108
Q

what pathogens are spread mainly through saliva

A

EBV, CMV, mumps

109
Q

what pathogens are spread by sexual transmission

A

viruses: HPV, HSV, HBV, HIV,
bacteria: T. pallidum, N. gonorrhoeae, C.trachomatis
fungi: Candida
protozoa: Trichomonas
Arthropods: Phthirus pubis (crabs)

110
Q

animal to human transmission is called what

A

zoonotic infections

111
Q

What does chlamydia cause in a male? female? both?

A

urethritis, epididymitis, proctisis

female: urethral syndrome, cervicitis, salpingitis
both: lymphogranuloma venerum

112
Q

What infections causes ectopic pregnancies in women

A

Neisseria gonorrhoeae

113
Q

Are viruses or bacterial infections more harmful to a fetus

A

viruses

114
Q

What are nosocomial infections

A

infections acquired at the hospital

115
Q

what is the most common cause of hospital acquired infections

A

hands of healthcare workers

116
Q

What is the main innate immune cell

A

NK

117
Q

what pathogens are known to stay latent until immune system is down

A

EBV and TB

118
Q

what are the mech in which microorganisms cause disease

A

contact or enter host and directly cause cell death
release toxins and kill cells or enzymes that slowly degrade
induce host immune responses causing additional damage

119
Q

What is the definition of tropism

A

predilection fo viruses to infect certain cells

120
Q

what are the factors for tropism

A
  • expression of host cell R for the virus
  • presence of cell transcription factors that recognize viral enhancer and promoter sequences
  • anatomic barriers
  • local temp, pH and host defenses
121
Q

What does HIV use to enter host

A

its glycoprotein gp120 binds CD4 T cells via CXCR4 and CCR5

122
Q

How does EBV get into cells

A

its envelop eglycoprotein gp350 cinds complement R 2 (CR2/CD21) on B cells

123
Q

Why do rhinoviruses infect upper respiratory tract only

A

replicate optimally at lower temp in URtract

124
Q

What are the direct cytopathic effects of viruses

A

some viruses kill cells by preventing synthesis of host macromolecules(DNA RNA) by enzymes and toxic proteins or inducing apoptosis

125
Q

What is the primary cell defense for viruses

A

CTLs

126
Q

Bacterial damage to host depends on what

A

ability to adhere and enter/invade or deliver toxins

127
Q

what is the role of plasmids and bacteriophages in infections

A

can pass virulent elements into other cells

like codes for Ab-resistance

128
Q

what are the two main types of Ab-R bacteria

A

vancomycin R enterococci and methicillin-R staphylococci

129
Q

What is quorum sensing

A

how many bacteria can coordinate and regulate gene expression in large populations

130
Q

How does S. aureus specifically coordinate virulence factors

A

secrete autoinducer peptides stimulating toxin production

131
Q

What are biofilms

A

a viscouse layer of extracell polysaccharides that adhere to host and make bacteria inaccessible to immune effector mechanisms increasing their Resistance

132
Q

What type of infections are biofilms characteristic of

A

bacterial endocarditis, artificial joint infections, respiratory infections in CF patients

133
Q

What are Adhesins

A

bacterial surface molecules that bind host or ECM

134
Q

What bacteria utilizes protein F and teichoic acid to bind to fibronectin

A

Step pyogenes( gram +)

135
Q

What is on the strains of E colie that cause UTIs

A

specific P pills which binds to val(1a4) on uroepithelial cells

136
Q

What is the main mech in which N. gonorrhoeae evades immune system

A

type of pili expression

137
Q

How do bacteria enter host cells

A

using host immune response like coating bacteria with C3b

138
Q

Once coated by C3b what does mycobacterium TB do

A

binds CR3 on macrophages and is endocytosed then blocks fusion of phagosome wtih lysosome

139
Q

How does listeria monocytogenes spread

A

manipulate cell cytoskeleton

forms pore forming protein to evade macrophage degradation

140
Q

What are endotoxins? exotoxins?

A

endotoxins are components of bacterial cell

exotoxins are secreted by bacteria

141
Q

What is used Dx serotologically to differentiate bacteria

A

detection O antigen found on gram -

142
Q

What is the response to LPS

A

induces cytokines and chemokines of the immune system to enhance T lymph activation
but high levels thought to have role in septic shock b/c induce TNF IL1 IL12

143
Q

What R does LPS bind to

A

TLR4

144
Q

what are types of exotoxins

A

enzymes, toxins that alter intracell signaling, neurotoxins, SuperAg

145
Q

What bacteria produce A-B toxins

A

bacillus anthracis. V.cholerae and some strains E.coli

146
Q

What bacteria produce neurtoxins

A

clostriudum botulinum and clostridium tetanii

147
Q

How do superAg cause massive T cell activation

A

bind conservative portions of T cell R

148
Q

What bacteria produce Super Ag associ with TSS

A

S aureus and S pyogenes

149
Q

how can s pyogenes lead to glomerulonephritis

A

Ab bind Ag and form IC that deposit in the renal glomeruli

150
Q

What is the association with pathogens and cancer

A

usually involve chronic inflammation

151
Q

how do microbes evade the immune system

A

growth in niches that are inaccessible to host immune system
antigenic variation
R to innate immune defenses
impairment of effective T cell repsonses

152
Q

What pathogens replicate in sites that are inaccessible to host immune

A

C. difficile

S typhi in gall bladder

153
Q

how does malaria sporozoites evade immune

A

enter liver cells so quickly before immune response is effective

154
Q

What are the main mech which microbes express Ag to evade immune system

A

low dfidelity of viral RNA polymerases and reassortment of viral genomes create viral antigenic variation

155
Q

What is different between serotypes of S pneumoniae

A

different capsular polysaccharides expressed

156
Q

What viruses have high mutation rates

A

HIV and influenza

157
Q

What viruses can undergoe genetic reassortment

A

influenza and rotavirus

158
Q

what bacteria undergo genetic rearrangement

A

Borrelia burgdorgeri
N gonorrhoeae
Trypanosoma sp (african sleeping sickness)
Plasmodium sp. (malaria)

159
Q

what viruses/bacteria have large diversity of serotypes

A
Rhinoviruses
strep pneumoniae (meningitis)
160
Q

what are our initial defense mech on invading microbes

A

defensins, cathelicidins, thrombocidins

161
Q

How does E coli cause meningitis in newborns

A

sialic acid which won’t bind C3b so evades alternative C’ pathway

162
Q

how does salmonella reduce TLR activation

A

modifies LPS

163
Q

What bacteria secrete proteases that degrade Ab

A

Neisseria, haemophilus and streptococcus

164
Q

what pathogens multiply in phagocytes

A

bacteria: mycobacteria, listeria and legionella
fungi: cryptococcus, neoformans
protozoa: leishmania, trypanosomes, toxoplasmas

165
Q

what viruses produce prteins that block C’

A

herpes and poxviruses

166
Q

What pathway is largely inhibited by viruses

A

IFN JAK/STAT

167
Q

How do microbes affect the MHC molecules

A

can alter them to change peptide presentation or even inhibit the NK or T cells

168
Q

Herpes virus affects which MHC molecules

A

both

169
Q

EBV effects what immune cell

A

B cells

170
Q

TIV effects what immune cells

A

T cells, macrophages and dendritic

171
Q

What are patients with Ab deficiency like X linked agammaglobulinemia prone to

A

S pneumoniae, H influenzae and S aureus

and viral rotavirus and enteroviruses

172
Q

Patients with t cell defects are prone to what

A

intracell pathogens like viruses and some parasites

173
Q

patients with C’ defects are susceptible to what

A

S penumoniae. H influenzae and N meningitidis

174
Q

deficiencies in Neutrophils leads to what

A

increased s aureus infections and gram - bacteria

175
Q

What are patients who receive bone marrow transplant at higher risk for

A

aspergillus and pseudomonas species infections

176
Q

Patients with CF are prone to what infections

A

P aeruginosa
S aureus
Burkholdaria cepacia

177
Q

What are patients with sickle cell anemia prone to

A

encapsulated bacteria like S pneumoniae

178
Q

Burn victims are prone to what infection

A

P aeruginosa

179
Q

What is the difference of M. TB in normal patient vs AIDS

A

usually causes well formed granulomas with few mycobacteria present
in AIDS causes multiple profulsey macrophages which fail to coalesce into granulomas

180
Q

What are the 5 major patterns of tissue reaction to infection

A
Suppurative-Purulent infection
mononuclear/granulomatous
Cytopathic/cytoproliferative
Tissue necrosis
Chronic inflammation/scarring
181
Q

What is suppurative infection characterized by

A

increased vasc permeability and leukocytic infiltration, predominately neutrophils
release of pus

182
Q

What are the common pyogenic bacteria

A

gram + cocci

gram - rods

183
Q

What is pus formed from

A

neutrophils and liquefactive necrosis

184
Q

what is the difference of pneumococci and staphylococci in lungs

A

pneumo causes lobar pneumonia sparing the walls

staphylococci destroyes the walls and form abscesses that heal with scar formation

185
Q

acute mononuclear inflammation is usually in response to what

A

viruses

186
Q

what cell predominates in syphilis infection?

HBV?

A

syphilis is plasma cells

HBV is lymphocytes

187
Q

Granulomatous inflammation is distinctive of what type of infection? give examples

A

infectious agents that resist eradication and stimulate strong T cell mediated immunity
M.tb, Histoplasma capsulatum, schistosome eggs

188
Q

What type of necrosis typically happens in granulomatous inflammation

A

caseous

189
Q

What is the characterization of cytopathic-cytoproliferative reactions and what class of pathogens cause it

A

cell necrosis or proliferation usually with few inflammatory cells
viruses

190
Q

what are polykaryons and what viruses cause this

A

fusion of cells

measles and herpes virus

191
Q

C. perfringes causes what type of necrosis

A

gangrenous due to release of toxic material

192
Q

what causes “pipe stem” fibrosis of the liver or bladder wll

A

schistosomal eggs