Week 2 Flashcards

(139 cards)

1
Q

MacConkey agar

A

inhibits gram + bacteria, lactose fermenters become pink/purple

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2
Q

EMB agar

A

methylene blue inhibits gram + bacteria, lactose fermenters become dark purple/black (E. coli is green)

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3
Q

Salmonella

oxidase \_\_\_\_\_
gram \_\_\_\_\_\_\_
ferments \_\_\_\_\_\_
Lac \_\_\_\_\_
Invasive or noninvasive?
infects what part of GI tract?
A

oxidase -
gram -
ferment glucose
Lac -

INVASIVE
Small intestine

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4
Q

Typhoid fever

A

Caused by salmonella Typhi infection

1) enteric fever, systemic disease, fever
2) Human adapted - Colonizes gall bladder → carrier state or intestinal perforation
3) Constipation or inflammatory diarrhea –> Stepwise increase in temperature to high fever

4) 1-3 weeks incubation
- Can continue for 6-8 weeks

5) Can kill immunocompetent people
6) Has a capsule that helps with immune evasion

TX = abx

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5
Q

Non-typhoidal salmonella infection

A

Fecal-oral transmission from poultry, eggs, contaminated fresh produce

Febrile food poisoning 24-48 hrs after ingestion

Nausea, vomiting, headache, chills, fever, cramps, watery diarrhea

High neutrophils

Self-limited - no abx required

Can cause disseminated disease in HIV patients

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6
Q

Salmonella

Toxins/Virulence Factors

A

TYPE III SECRETION SYSTEM

1) Invasion via M cells with type III secretion system → transient bacteremia
2) Uptake by phagocytes (macs) via different type III secretion system → salmonella multiply

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7
Q

Typhoid vaccine

A

purified Vi polysaccharide (adults and children > 2 yrs)

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8
Q

Shigella

gram \_\_\_\_\_\_
oxidase \_\_\_\_\_
ferment \_\_\_\_\_\_
Lac \_\_\_\_\_\_\_
Invasive or noninvasive?
Infects what part of GI tract?
A
Gram -
Oxidase -
Ferment glucose
Lac -
INVASIVE
Large intestine
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9
Q

What is the infective dose of shigella?

A

Requires SMALL infective dose (very acid resistant)

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10
Q

Shigella diarrhea

A

inflammatory diarrhea, dysentery

Fever, malaise, vomiting, watery diarrhea → frank dysentery (frequent small stools with blood/mucus, cramps, tenesmus)

Humans are only known reservoir → fecal-oral from person to person (Food, fingers, feces, flies)

Can cause HUS (S. dysenteriae)

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11
Q

Incubation time for Shigella

A

Incubation 1-4 days

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12
Q

Shigella

Toxins/Virulence Factors: (2)

A

1) ENTEROTOXIN –> produce watery diarrhea

2) TYPE III SECRETION SYSTEM

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13
Q

Type III secretion system in Shigella mechanism of invasion and spread

A

ntry via M cells, uptake by macrophages → induce apoptosis and inflammation (IL-1/IL-8)

Invade basal side of epithelial cells, lyse vacuole, grow in cytoplasm, spread directly into neighboring cells

Only S. dysenteriae (type 1) make cytotoxic Shiga toxin

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14
Q

E. Coli

gram \_\_\_\_
shape?
Ferment \_\_\_\_\_
Oxidase \_\_\_\_\_
Lac \_\_\_\_\_
A
Gram -
rod
ferments glucose
oxidase -
lac +
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15
Q

ETEC (Enterotoxigenic)

Diarrhea

A

traveler’s diarrhea, severe watery, no blood/pus, abdominal cramps, vomiting

Toxigenic, NONINVASIVE

Infects small intestine

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16
Q

ETEC (Enterotoxigenic)

Toxins/Virulence factors (3)

A

1) Heat labile enterotoxin
2) Heat stable enterotoxin
3) Fimbrial adhesins → colonize small intestine

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17
Q

ETEC (Enterotoxigenic)

Treatment

A

supportive, fluid replacement

Do NOT use abx

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18
Q

Heat labile enterotoxin

A

Present in ETEC

similar to CHOLERA TOXIN but binds to different gangliosides (different B-subunit) than cholera → target different populations

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19
Q

Heat stable enterotoxin

A

Present in ETEC

small peptide toxin, activates guanylate cyclase → increased cGMP → increase fluid secretion

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20
Q

EHEC: Enterohemorrhagic

Diarrhea

A

bloody, hemorrhagic colitis, dysentery

INITIAL WATERY diarrhea → grossly BLOODY

Fever can be seen

Fecal leukocytes uncommon **

Primarily toxigenic - NONINVASIVE

Infects large intestine

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21
Q

EHEC: Enterohemorrhagic

Infectious dose?
Incubation period?
Possible complications?

A

Requires only small infectious dose (acid stable)

3-9 days of incubation

Can cause Hemolytic Uremic Syndrome (HUS)

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22
Q

EHEC: Enterohemorrhagic

most common serotype

A

O157:H7 serotype = colorless colonies on sorbitol-MacConkey media (does NOT ferment sorbitol)

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23
Q

EHEC: Enterohemorrhagic

Treatment

A

supportive
NO abx

abx → increase risk of HUS by increasing expression of shiga-like toxin

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24
Q

EHEC: Enterohemorrhagic

Toxins/Virulence Factors:

A

1) Attaching and effacing

2) Shiga-like cytotoxins Stx-1 and Stx-II

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25
Shiga-like cytotoxins Stx-1 and Stx-II
chromosomally encoded by lysogenic toxin-converting bacteriophages Stx binds Gb3 sphingolipids of enterocytes and renal endothelial cells Stx-A subunit → binds rRNA → inhibit protein synthesis → tissue damage
26
EPEC: Enteropathogenic Diarrhea
watery, persistent diarrhea in infants (<1yr), no blood/mucus, no tissue invasion, vomiting, low grade fever, prolonged, can have relapse NON INVASIVE
27
EPEC: Enteropathogenic Treatment
rehydration, responsive to abx
28
EPEC: Enteropathogenic Main toxin/virulence factor
Attaching and effacing (AE) | -TYPE III SECRETION SYSTEM
29
Attaching and effacing toxins
Present on EHEC and EPEC 1) Adhere to enterocyte surface 2) **Type III secretion system secretes intimin receptor → microvilli destruction, pedestal formation → interferes with absorption
30
Yersinia spp: Gram _____ Oxidase ____ ferment _____ Infects what part of GI tract?
Gram - Oxidase - Ferment glucose Infects small intestine
31
Yersinia spp: disease
Associated with eating undercooked pork, dairy products Disease: low grade fever, watery diarrhea + some blood + fecal leukocytes Infects terminal ileum RLQ pain → MIMIC APPENDICITIS Can cause reactive arthritis (especially in HLA-B27) ABX not very effective
32
Vibrio cholerae Gram _____ Oxidase ____ Invasive or noninvasive? Infects what part of GI tract?
Gram - Oxidase + NONINVASIVE Infects SMALL INTESTINE
33
Vibrio cholerae Diarrhea
Non invasive diarrhea - profuse, watery, “rice water” Caused by ENTEROTOXIN (primarily toxigenic) 2-5 day incubation period Abrupt onset diarrhea, abdominal cramps, vomiting - NO FEVER
34
Vibrio cholerae Treatment
fluid replacement + abx (can shorten infection)
35
Vibrio cholerae
1) Enterotoxin - Cholera Toxin | 2) TCP Pilus
36
Cholera Toxin
BACTERIOPHAGE (CTX) conversion is important, uses TCP pilus to transfer toxin gene Has A-B type toxin Cytotonic (does NOT kill the cell)
37
A-B type toxin
Cholera toxin B-subunit: binds to cell surface receptors (ganglioside GM 1) of enterocytes A-subunit: enters cell cytoplasm, transfers ADP-ribose from NAD to G-protein → constitutive activation of adenylate cyclase → increase cAMP → Cl- secretion → fluid loss
38
TCP Pilus
Cholera toxin surface-expressed adherence factor (toxin coregulated pilus)
39
Transmission of cholera
Fecal-oral transmission (water, contaminated foods, shellfish)
40
Vibrio parahaemolyticus
in salt water Gastroenteritis, wound infections, septicemia Associated with raw/undercooked shellfish Can produce bloody stools → produces hemolysin
41
Vibrio vulnificus
gastroenteritis/wound infections from contaminated seafood (oysters) and extraintestinal infections in immunocompromised
42
Campylobacter ``` gram ____ size and shape? oxygen requirement? Temperature requirement? Oxidase ____ Catalase _____ Ferment _____ ```
``` Gram - small, curved rod microaesophilic Grows best at 42 C Oxidase + Catalase + Ferments glucose ```
43
Dose requirement for Campy infection?
Low dose required for infection
44
Campylobacter diarrhea
diarrhea, fever, abdominal cramping, +/- bloody stools +/- fecal leukocytes Invades terminal ileum and proximal colon Food borne gastroenteritis (poultry, milk, water, pets) Most common cause of gastroenteritis in Western world
45
Complications of Campylobacter infection (2)
1) Guillain-Barre syndrome - molecular mimicry between LPS antigen and GM1 ganglioside = ASCENDING paralysis 2) Reiter’s syndrome (autoimmune reactive arthritis) possible (especially HLA-B27)
46
Treatment of Campylobacter
fluid replacement, abx in severe cases (erythromycin, quinolones)
47
Helicobacter ``` Gram ____ shape? Motility? oxidase ____ urease ____ ferment ______ Oxygen requirements Isolated on _______ agar ```
``` gram - curved, rod highly motile oxidase - Urease + Ferments glucose Microaerophilic ``` Isolated on Campy agar
48
Helicobacter Disease
gastritis, gastric/duodenal ulcers, gastric adenocarcinoma, MALToma MOST common human bacterial pathogen Colonizes mucous layer of stomach - does NOT invade Causes mucosal inflammation, epithelial cell damage, and neutrophil infiltration
49
Helicobacter Treatment
Triple therapy: PPI + amoxicillin + clarithromycin x 14 days
50
LPS (lipopolysaccharide)
in outer membrane of all gram neg bacteria Made up of Lipid A + core polysaccharides + O antigens
51
Lipid A
toxic part of LPS (endotoxin), outer layer
52
Core polysaccharides
constant region of LPS within a genus
53
O antigens
repeating subunits of oligosaccharides, variable, used for species identification
54
H antigens
flagella (motile organisms only)
55
K antigens
capsular polysaccharide (increases virulence, not in all strains)
56
Watery diarrhea symptoms what part of GI tract affected 4 bugs
copious, watery, no blood or pus, no tissue invasion, in small intestine Small intestine disease usually secretory diarrhea → ETEC, EPEC, Campylobacter, Vibrio cholerae
57
Dysentery symptoms what part of GI tract affected 4 bugs
scant volume, blood/pus/mucus present, tissue invasion in large intestine → Shigella, Entamoeba histolytica, EIEC, Campylobacter
58
Protracted diarrhea
lasting > 14 days | → EPEC
59
Bloody, watery diarrhea symptoms what part of GI tract affected 3 bugs
copious, some blood/pus, invasion in Ileum or colon Salmonella, Campylobacter, Yersinia
60
Hemorrhagic colitis symptoms what part of GI tract affected 1 bug
copious, like liquid blood, no leukocytes/ invasion, in large intestine → EHEC Large intestine infection typically inflammatory
61
2 bugs that require high infectious dose 2 bugs that require low infectious dose
More sensitive to acid → requires higher infective doses Vibrio, ETEC Resistant to acid → requires low infective dose Shigella, Salmonella
62
4 bugs that cause noninvasive diarrhea
V. Cholera, ETEC, EHEC, EPEC
63
3 bugs that cause invasive diarrhea
Shigella, Salmonella, S. Typhi Produce inflammatory diarrhea + frequent/low-volume/mucoid/bloody stools + tenesmus + FEVER + abdominal pain + MANY LEUKOCYTES Sheets of leukocytes in stool indicative of colonic damage
64
Zipper model
tight interaction between bacterial cell surface ligands and host cell receptors → host cell surface closes around bacterium
65
3 bugs that use the zipper model
1) Parasite induced phagocytosis (Listeria) 2) Receptor-mediated phagocytosis of macrophages (TB) 3) Coiling phagocytosis (Legionella)
66
Trigger model + two bugs that use this
bacterial products induce cell surface to take up bacteria Type III secretory systems cause this (Salmonella, Shigella)
67
Listeria ``` gram ______ Shape? Catalase _____ Spore forming? Hemolysis? Motility? Intracellular or extracellular? ```
``` Gram + Rod Catalase + Non-spore forming B-hemolytic TUMBLING motility extracellularly Facultative intracellular ```
68
Listeria grows at what temperatures? What things can you eat that are associated with Listeria?
Grows at refrigerated temperatures → poorly pasteurized milk/cheeses, deli meats, raw vegetables
69
How does listeria enter the body?
Uses “Zipper Mechanism” - penetrates GI mucosa, invades phagocytes → grows/spreads intracellularly
70
How does listeria replicate?
spreads cell to cell without exposure extracellular environment using actin-based cellular contractile mechanism (actin rocket) NO exposure to antibodies, complement or neutrophils with cell-to-cell spread → Cell mediated immunity critical
71
2 main virulence factors of Listeria
1) Produces an endotoxin - only gram + organism with endotoxin - Has tropism for nervous tissue → meningitis 2) Listeriolysin O bacterial toxin: digests phagosome allowing Listeria to infect target cell
72
How is listeria transmitted? (3)
Ingestion of bacteria in food Placental transmission Vaginal transmission
73
Susceptible populations for severe Listeriosis (meningitis and sepsis)
Susceptible populations = pregnant women, neonates, elderly, AIDS patients due to deficiency cell-mediated immunity
74
Consequences of Listeria bacteremia in pregnancy
3rd trimester amnionitis, preterm labor, spontaneous abortions, stillbirths
75
Granulomatosis infantiseptica
placental transmission of Listeria to infant → early onset sepsis, granulomas throughout body, rash
76
Listeria Infection in Immunocompetent person causes what?
febrile gastroenteritis
77
Treatment of Listeria
ampicillin, penicillin G, TMP-SMX +/- Gentamicin
78
Legionella ``` Gram _____ shape? Special stain? Intracellular or extracellular? Oxidase _____ Grows on what special agar? 2 important cofactors... ```
``` Gram negative rod (weak gram stain) Silver stain Facultative intracellular Oxidase + Grows on charcoal yeast extract with IRON and CYSTEINE ```
79
Transmission of Legionella
aerosols from environmental water sources (air conditioning, hot water tanks)
80
Two diseases caused by legionella infection
1) Legionnaire's Disease | 2) Pontiac fever
81
Legionnaire’s Disease
severe pneumonia, lobar Nonproductive cough Confusion, DIARRHEA Signs of kidney damage (proteinuria, microscopic hematuria) HYPONATREMIA - due to SIADH or renal tubulointerstitial disease impairing sodium reabsorption Diagnosed by presence of ANTIGEN IN URINE
82
Pontiac fever
mild flu-like illness (fever, chills, fatigue, malaise, headache) WITHOUT respiratory symptoms
83
Treatment of Legionella infection
Macrolides (Azithromycin) + Fluoroquinolones (Levofloxacin)
84
How does legionella invade and replicate?
Enters respiratory tract, taken up by macrophages → inhibits phagosome-lysosome fusion → intracellular replication
85
Obligate intracellular organisms (5)
cannot reproduce outside cell ``` Chlamydia Coxiella burnetii Ehrlichia Mycobacterium leprae Rickettsia ```
86
Facultative intracellular organisms
capable of both intra and extracellular growth 1) Bartonella 2) Brucella 3) Francisella 4) Legionella 5) Listeria 6) Mycobacterium 7) Nocardia 8) Salmonella 9) Shigella
87
Aminoglycosides vs. Tetracyclines for treatment of intracellular organism infections: Aminoglycosides (gentamicin): enters into cells via ________ → ___________ → accumulates in _________ Tetracyclines: enter into cells via ________ → action in ________
Aminoglycosides (gentamicin): enters into cells via PINOCYTOSIS → phagosomes fuse with lysosomes → accumulates in lysosomes Tetracyclines: enter into cells via DIFFUSION → action in cytosol
88
Signs and symptoms of VIRAL gastroenteritis
ACUTE onset WATERY diarrhea (no blood/mucus) +/- vomiting Nausea, intestinal cramping, muscle aches, low grade fever
89
Epidemiology of VIRAL gastroenteritis incubation and duration? shedding phase length? transmission how?
Short incubation and duration of symptoms with prolonged asymptomatic shedding phase Transmitted on surfaces, food, and water (STABLE) Seasonal transmission Person-to-Person or Fecal-Oral
90
Pathophysiology of viral gastroenteritis infection (4)
1) LOCAL infection of intestinal epithelial cells 2) MALABSORPTION due to virus killing mature enterocytes 3) Local VILLUS ischemia 4) Viral ENTEROTOXIN → transepithelial fluid loss
91
What is the best way to diagnose viral gastroenteritis?
Multiplex RT-PCR detection of viral nucleic acids in stool = most sensitive RIA or ELISA for ab can tell if exposure occurred, not if there is active infection
92
Calciviruses (2)
1) Norovirus | 2) Sapvirus
93
Norovirus size? enveloped? genome? (DNA vs. RNA, etc.) shape?
Small non-enveloped ssRNA (+ sense) Cup shaped (chalice-like) indentations (golf ball)
94
Norovirus has ______ and _______ which causes antibody to only give short-term protection
strain diversity and antigenic shift
95
Individuals homozygous ____________ are highly resistant to norovirus infection
Individuals homozygous non-secretors of FUT2 are highly resistant to norovirus infection
96
Disease caused by Norovirus
⅓ infected are asymptomatic and shedding virus Vomiting, watery diarrhea, nausea, cramping, malaise, headaches, myalgias, low grade fever Quick on, quick off
97
Incubation, duration, and shedding of Norovirus infection
``` Incubation = 15 hrs - 2 days Duration = 1-2 days Shedding = up to 8 weeks ```
98
Norovirus infections are associated with which locations? how is it spread?
Cruise ships, hospitals, nursing homes Fecal-oral person-to-person transmission Year round outbreaks (less seasonal as rotavirus)
99
Rota virus: genome? Shape? Envelope? Season of most infections?
11 genome segments of dsRNA + RNA-dependent RNA-polymerase (each encodes ssRNA that makes 1 protein) Rota = Wheel Non-enveloped WINTER
100
Rotavirus protein shell is made up of what 3 layers?
1) Outer capsid layer: VP7 with VP4 spikes → acid stability, induces neutralizing antibody 2) Inner capsid layer: VP6 3) Innermost core: VP2
101
When two different rotaviruses infect the same cell, what happens?
Reassortment of genome when two different rotaviruses infect same cell
102
Rota virus virions are not infectious unless activated by _________
Trypsin
103
Rota virus causes what disease
Infects small intestine and replicates in villus epithelial cells → villous shortening and stunting High viral titers shed in stool Abrupt onset fever, vomiting, then diarrhea (explosive, nonbloody, watery)
104
Rota virus incubation duration shedding
Incubation period: 1-3 days Duration: 4-8 days, self-limited Shedding can occur for > 3 weeks
105
Treatment of Rotavirus is it preventable?
REHYDRATION | Preventable by vaccination
106
Rotavirus vaccine
RotaTeq: Pentavalent live bovine rotavirus vaccine Rotarix: monovalent live human rotavirus vaccine Associated with increased risk of intussusception
107
Diagnosis of Rotavirus
ELISA Rotazyme identification
108
Enteric Adenoviruses: eveloped? shape? genome?
Non-enveloped Icosahedral dsDNA virus
109
Enteric Adenoviruses: Diseases (2)
1) URI symptoms (conjunctivitis, pharyngitis, pneumonia, hemorrhagic cystitis) + gastroenteritis (serotypes 40 and 41) 2) Watery diarrhea, then vomiting lasting 5-12 days (longer than Nora/Rota) - persistent, but less severe
110
Astroviruses size? envelope? genome? shape?
Small, non-enveloped ssRNA (+ sense) Star shaped capsomers
111
Astroviruses CAN be grown in cultures of _____________ Requires ________ to activate virus infectivity
CAN be grown in cultures of human intestinal epithelial cells Requires trypsin to activate virus infectivity
112
HPV main features
papillomavirus Small, non-enveloped, icosahedral DNA virus
113
Two main structural proteins of HPV (late genes) and what they are used for
Major capsid protein L1 → basis of vaccine, outer part of virus Minor capsid protein L2 → required to produce infectious virus particles
114
HPV Lifecycle/Invasion
Invades only undifferentiated proliferating basal cell layers in epithelium → Infect epithelium of skin, anogenital tract, and oropharyngeal mucosa Replicates upon epithelial differentiation Releases virus particles from fully differentiated skin layers
115
HPV Transmission
sexual contact oral/genital and mother-newborn (vertical transmission)
116
Risk factors of HPV infection:
``` Early onset intercoars (before age 20) Multiple sexual partners History of genital warts Immunosuppressive disorders (HIV/AIDS) Failure to receive regular Pap test screening Long term use of oral contraceptives ```
117
Persistence of HPV infections
80% of HPV infections transient and cleared within 1-2 years 10% get persistent infection - persistence of high-risk HPV type is required for cancer development AND maintenance → <1% develop cancer
118
6 diseases caused by HPV
1) Common wart (verruca vulgaris) 2) Plantar wart (verruca plantaris) 3) Anogenital wart: (condyloma cumintaum) 4) Respiratory papillomatosis 5) Epidermodysplasia verruciformis 6) Squamous cell carcinoma
119
Common wart (verruca vulgaris) caused by HPV ____ or ____
small, rough tumor, on hands/feet HPV2, HPV7
120
Plantar wart (verruca plantaris) caused by HPV ____, ____, or ________
on sole or toes of foot | HPV1, HPV2, HPV4
121
Anogenital wart: (condyloma cumintaum) caused by HPV ____ or ____
sexually transmitted HPV6 and HPV11
122
Respiratory papillomatosis caused by HPV ____ or ____
warts on larynx or in respiratory tract HPV6 and HPV11
123
Epidermodysplasia verruciformis
rare AR disease, increased susceptibility to HPV
124
Squamous cell carcinoma caused by HPV 5 types of HPV that can cause this?
Cervical cancer or head/neck cancer HPV16, HPV18, HPV31, HPV33, HPV45
125
Cervical cancer is typically caused by _____ and arises where?
HPV arise within transformation zone (squamocolumnar junction) Especially associated with HPV 16 and 18
126
High risk HPV: (6)
HPV16, HPV18, HPV31, HPV33, HPV45, HPV58 These are covered by current vaccine
127
Low risk HPV: (2)
HPV6, HPV11
128
HPV oncoproteins
cancer regresses when E6 and E7 are blocked E6 protein: binds and degrades p53 E7 protein: binds phosphorylated-RB → release E2F transcription factor → activate cell replication and cell cycle progression HPV can integrate into host chromosome → uncontrollable expression of E6/E7
129
HPV Vaccine
want to vaccinate before sexually active Gardasil: contains 6, 11, 16, and 18 Cervarix: contains 16 and 18 Gardasil-9: contains 6, 11, 16, 18, 31, 33, 45, 52, 58 *How vaccine is made: HPV L1 protein only, an empty virus → immune response without risk of infection
130
Screening and diagnosis of cervical cancer
HPV pap smear / HPV test → positive, then test cytology, if negative, test again in 3-5 years → positive cytology then do colposcopy
131
Cause of acute endocarditis
Staph aureus Most common sites: mitral > aortic > tricuspid > pulmonic
132
Causes of subacute endocarditis (3)
Viridans strep, Strep bovis, Enterococci (faecalis)
133
What are predisposing factors to developing subacute endocarditis?
pre-existing cardiac lesion → turbulent, non-laminar blood flow, endothelial trauma, and fibrin deposition
134
Cause of prosthetic valve endocarditis
coagulase negative staph (S. Epidermidis)
135
Local complications of endocarditis?
effect integrity of heart valves → valvular insufficiency, CHF, myocardial and valve ring abscesses, pericarditis, conduction system disturbances
136
What are embolic complications of endocarditis? (7)
EMBOLI released from valve vegetation 1) Stroke or PE 2) Splinter hemorrhages 3) Petechiae, subconjunctival hemorrhages 4) Janeway lesions: nontender flat lesions on digits 5) Osler's nodes: tender, purplish raised papules on digits 6) Roth Spots: retinal flame-like hemorrhagic 7) Septic emboli to kidneys
137
What are immune complex deposition complications of endocarditis? (3)
1) Glomerulonephritis 2) Osler’s nodes (small vessel vasculitis) 3) Roth spots
138
Presentation of Necrotizing Fasciitis (4)
1) Presents with signs of systemic toxicity (hypotension, tachycardia, fever, leukocytosis) 2) Poorly defined area of erythema + pain out of proportion to physical exam - Very tender in areas that are not erythematous → suggest deep tissue involvement - Get thrombosis of small vessels and destruction of superficial nerves 3) Spreads along facial planes 4) Later findings: skin breakdown + bullae + anaesthesia
139
Bugs with a type 3 secretion system? (5)
``` EHEC EPEC Shigella Salmonella (typhoidal, and non-typhoidal) Yersinia ```