ID Exam 1 Flashcards
1
Q
How can we vaccinate children under two months of age?
A
Give vaccine to mother -> maternal antibodies
Ex: whooping cough vaccine in 3rd trimester
2
Q
Whooping cough vaccine age groups
A
Tdap: 11 years and older, including pregnant women
DTaP: children 2 months to 6 years
3
Q
Vaccines contraindicated in pregnancy and immunocompromised
A
Varicella
Zoster
MMR
4
Q
Special use vaccines
A
Anthrax Rabies Small pox TB Typhoid Yellow fever Japanese encephalitis
5
Q
Types of bacteria that don’t gram stain
A
No cell wall (mycoplasma, chlamydia)
Intracellular
Other: M. TB, spirochetes, legionella
6
Q
3 common lactose fermentors
2 rare
A
E coli, klebs, enterobacter
citrobacter, arizona
7
Q
3 common non-lactose fermentors
A
pseudomonas, salmonella, shigella
8
Q
2 gram positive rods and size
A
Small: listeria
Lage: clostridium
9
Q
3 factors that affect infection/dz
A
- Host: behavior, susceptibility, response
- Agent: prevalence, virulence
- Environment
10
Q
G+ staining factors
A
Teichoic acid (binds epithelial cells) Thick PG wall (one wall)
11
Q
G- staining factors
A
Endotoxin/LPS Periplasmic space (ß-lac location) Thin PG layer (two membranes)
12
Q
Enterococcus
A
S. Facealis
S. Faecium (VRE)
13
Q
Staph Aureus virulence
A
Protein A
Capsule
Teichoic acid
14
Q
Two conditions you can see chronic staph infections
A
Chronic granulomatous disease Hyper IgE (Job's)
15
Q
Staph vs. strep scarlet fever
A
Strawberry tongue in strep only
16
Q
Staph aureus toxins
A
Exfolatin: Scalded skin and scarlet fever
TSST-1: TSS
Enterotoxin: preformed - food poisioning
17
Q
Lancefield groups of strep
A
A: beta hemolytic, throat
B: beta hemolytic, vagina
D: none, E faecalis/E faecium, intestinal tract
18
Q
G A Strep virulence factors
A
M proteins
Attachment: pili and fibronectin binding
Spreading: streptokinase, hyaluronidase, DNA-ase
Toxins: ExoA (TSSL), ExoB (nec fac), A and C (scarlet)
Streptolysin O: RBC lysing
19
Q
Eagle effect
A
In SEVERE strep treatment
Clinda is better as beta lactams may cause mass release of toxins
Clinda is static, less toxin, better clinical use
20
Q
Clinical predictors of bacterial vs viral sore throat
A
Bacterial = tender LN, close contact spread Viral = runny nose, cough, <3yr old
21
Q
Strep leading to rheumatic fever risk factors
A
M3 or M18 strain
Family history
Higher ASO titer
PREVENTABLE with abx tx (as opposed to PSGN)
22
Q
PSGN
A
Not preventable with abx
Only certain M types (M4, M12, M49)
IC deposition in glomerulus BM
23
Q
ASO titers in strep infection
A
Only for RF and PSGN
Not for acute infection
24
Q
Infective dose and acid stability
A
Acid stable organisms have lower infective dose
Shigella (10-100) and EHEC (10^3)
Infective dose decreased with food (protection)
25
G- antigens
LPS: (lipid, A, core sacc, O antigen)
| Flagellum -> H antigen (motile) T3SS
26
Genetics of virulence (plasmids, bacteriophage conversion, and chromosomal)
Plasmids: resistance, pili, entertox, secretion systems
Bacteriophage conversion: toxins (shiga, cholera)
Chromosomal: PI's (regions in DNA)
27
Non-invasive enterics
Cholera
ETEC
EPEC
EHEC
28
Invasive enterics (tend to be inflammatory, therefore WBC in stool sample)
```
Shigella
EIEC
Salmonella
Yersinia
Campy
```
29
Cholera: serogroup, enterotoxin/mech, path, stool, tx
```
Serogroup A1
Cholera toxin (bacteriophage conversion
Perm binding of AC (increase cAMP, and Cl out)
B binds cell, A trans toxin
Rice water stool
ORT, tetracycline if SEVERE
```
30
ETEC: toxins and mech, tx
Heat Labile: increase cAMP
Heat Stable: increase gGMP
Non-hemorrhagic stool
Tx: FQ's
31
EPEC: setting, virulence/target, path
Watery diarrhea in developing country kids
LEE T3SS, Intimin R and inhibit pedestal formation
Loss of microvili leads to malabsorption (increased O2 = more E. Coli)
32
EHEC: plate fermenting, resivoir, virulence, complications
Sorbitol non-fermenting
Cow resivoir (undercooked beef)
LEE T3SS and Shiga toxin
HUS
33
Shigella: virulence, targets, serotype difference, tx
T3SS, uptake, apoptosis of macs, inflammation
A: shiga toxin, dysentery, HUS (O antigen variation)
Tx: Cipro
34
Salmonella non-typhi: transmission, incubation, tox, tx
```
Food transmit
6-24 hr incubation
PMNs
SPI1 T3SS: invasion, into enterocyte
SPI2 T3SS: survival in macs (replicate in vacuoles)
Self limiting, Cipro in compromised
```
35
Salmonella typhi: transmission, incubation, tox, tx
```
Person to person
1-3 weeks
Mononuc phags
SPI1 T3SS: invasion, into enterocyte
SPI2 T3SS: survival in macs (replicate in vacuoles)
Capsule
Typhoid toxin (A2B)
Vaccine (live attenuated)
Cipro and ceftri
```
36
Campy tox, tx
Flagella
Cytolethal
Distending toxin
Erythromycin
37
H. Pylori tx
PPI, bismuth, clarithromycin, amox, metro
38
Watery diarrhea: characteristics, bugs
Copious, no blood or pus
| ETEC, EPEC (esp >14d), (campy)
39
Dystentery: characteristics, bugs
Scant volume, pus/mucus present
Tissue invasion, large intestine
Shigella, EIEC, (campy)
40
Bloody, watery: bugs
Salmonella, campy, yersina
41
Hemorrhagic colitis
Liquid blood, no leuks
| EHEC
42
Signs of invasive diarrhea
```
Penetration of intestines
Decreased volume of stools/blood/mucus (due to inflammation)
Increased pain and cramps
Presence of fecal leuks
Fever
```
43
General signs of viral GI infection
Short on/short off
Prolonged shedding, stable viruses
Seasonal
>75% gastroenteritis is viral
44
Pathophys of viral GI
```
Local infection of enterocytes
Malabsorption (enterocyte loss)
Local vilus ischemia (blunting)
Viral enterotoxin
Dx often not needed but helpful with outbreak, immunocompromised, and severe cases
```
45
Reinfection with viral GI bugs
Common due to:
Different virus
Multiple serotypes
Short lived immunity
46
Calcivirus (norovirus): characteristics, epi, settings, immunity, dx, tx
ssRNA + sense, naked, GII.4 Sydney = US outbreaks
Fecal-oral, surface
8 weeks Asx. shedding, 10-100 infective dose
Cruise ships, nursing homes, hospitals
~6mo immunity (homo FUT2 = heavy resistance)
Dx = PCR, Tx = Rehydration
47
Rotavirus: viral structure and toxin
Outer capsid: VP7 w/ VP4 spikes
Inner capsid: VP6
Toxin = NSP4 (increase Cl, maybe destab membrane and increase Ca2+)
Group A is responsible for human infections
48
Rotavirus: epi and shedding
50% Asx.
Winter (seasonal)
4-8 days (1-3 incubation, 3 weeks shedding)
49
Rotavirus and calcivirus vaccines
```
Rotavirus: live vaccine, taken orally
Increased risk of intisusseption
Rota Teq (RV5) pentavalent like bovine (98% against severe dz) - 3 doses (2,4,6 months)
Rotarix (RV1) monovalent live human (85% against severe dz) - 2 doses (2,4 months)
```
50
Astroviruses
Naked star shaped
Needs to be activated by trypsin
7 serotypes identified
51
Adenovirus: GI infection
Serotypes 40 and 41
Naked, dsDNA virus
Fecal-oral, no seasonality
Diarrhea THEN vomit 5-12 days
52
Methods of entry and bugs for intracellular pathogens
Zipper: Listeria, mycobacterium TB, legionella (tight interaction with engulf)
Trigger: Salmonella, Shigella (T3SS)
53
OBLIGATE intracellular
Chlamydia, coxiella, ehrlichia, mycobacterium leprae (deficient in genes), rickettsia
54
FACULTATIVE intracellular
All ella's except coxiella, listeria, mycobacterium TB, nocardia, salmonella, shigella
55
Host defenses for intracellular bugs to avoid and examples
1. NADPH Oxidase (Listeria, shigella = leave vacuole, salmonella = produces SOD takes ROS to H20)
2. Avoid fusion with lysosomes (legionella, chalymydia)
3. Fusiogenic (coxiella)
4. Survives in RBC's (bartonella)
56
Top infections causing cancer (20% of cancer)
1. H pylori
2. HBV, HCV
3. HPV
57
HPV etiology, cancer caused
Naked, dsDNA
| Cervical (100%) and HandN (25%) CA
58
Late vs early genes in HPV
L1, L2
E1-E7
L1: Major capsid
L2: Minor capsid
E6: p53 disruption
E7: RB disruption (E2F)
E5: also virulence, proliferation, transformation, escape
E2: genome maintenance, deletion leads to increased E6 and E7 expression
59
HPV life cycle
Epithelial/skin cell infection
Only infects basal layers
Only released from fully differentiated upper layer
60
HPV risk factors
```
Early onset sex (<20yr so basically everyone)
Multiple partners
Warts
Immunocompromised
Oral sex -> oral infection
Smoke, OCP
```
61
```
Common types of HPV
Common wart
Plantar wart
Anogenital wart
Respiratory papillomatosis (larynx warts)
Epidermaldysplasia verruciformis
Cervical CA
HN CA
```
Common wart: 2,7
Plantar wart: 1,2,4
Anogenital wart: 6, 11
Respiratory papillomatosis (larynx warts): 6, 11
Epidermaldysplasia verruciformis: AR susep. to HPV
Cervical CA: 16 (50%), 18, 31, 33
HN CA: OPSCC (25%)
62
HPV Screening
Ages
Flowchart
```
<21, >65 yrs: none
21-29: every 3
30-65: every 5
If positive -> cytology -> colposcopy
If cytology neg -> repeat 6-12 months
```
63
HPV vaccine
```
L1 only, no L2
No therapeutic effect
Gardisil: 6,11,16,18
Cervarix: 16,18
Gardisil-9: 6,11,16,18,31,33 and more
```
64
Basic features of herpes viruses
Liner, dsDNA, envelope
Latent in cells
Intranuclear inclusions
Multinuclear cells
65
Alpha HHV: virus, latency, replication speed
HSV1/2, VZV
Latent in neurons (trigeminal and sacral ganglion ex)
Fast replication
66
Beta HHV: virus, latency, replication speed
CMV, HHV6/7
Latent in myeloid cells (CD-34 positive, lymphs and macs)
Slow replication
67
Gamma HHV: virus, latency, replication speed
EBV, HHV8
Latent in B cells (CD-21 positive)
Very slow replication
68
Replication cycle basics
1. Infection/enter (glycoproteins)
2. Unloads dsDNA -> circle = episome
3. Gene expression: Immediate early, early, late
4. Protein/capsid enters nucleus to package (inclusions)
5. Egress via Golgi
69
HHV gene expression: early/late
Immediate early: conducive environment
Early: replication
Late: structural proteins (for exit)
70
Viral inclusions
Nuclear acidic: Cowdry bodies (HSV, VZV) alpha
Nuclear basic: Owl eyes (CMV)
Nuc/cyto: HH6/CMV, beta
71
HSV-1: location, transmission, clinical manifestations, latency
```
Above the belt (<50% in common with HSV-2)
Respiratory secretions/saliva
Gingivostomatitis, erythemia multiformis
Encephalitis, herpetic keratitis
Latent in trigeminal ganglion
```
72
HSV-2: location, transmission, clinical manifestations, latency
```
Below the belt (<50% in common with HSV-1)
Sexual contact, genitals
Can lead to pharyngitis (oral sex)
Meningitis
Latent in sacral ganglion
```
73
HSV Reactivation
Shortened course of illness compared to original
Rarely systemic
No antiviral tx
Possible but rare: encephalitis/meningitis via reactivation
74
```
Herpes encephalitis (HSV-1):
Clinical
CSF
Imagining
Tx
```
Clinical: Fever, HA, AMS
CSF: mononuclear cells, HSV DNA (PCR)
Imaging: MRI>CT
Tx: IV Acyclovir
75
HHV-3: presentation, complications, treatment, vaccine
```
VZV (varicella and zoster)
Lesions in various stages of healing
Encephalitis, pneumonia
Post herpetic neuralgia (decreases with tx)
Tx: acyclovir within 3 days of start
Vaccine for both. Zoster >60yrs
```
76
HHV-5 populations and consquences, treatment
CMV
Teens: mono, spot - (esp if immunocompetent)
Transplant patients: pneumonia
HIV patients: retinitis
Most common HHV infection in newborns (often mild)
TORCHES (severe, reflects material immune status)
Tx: Gangcyclovir, Forcarnet if resistant
77
HHV6/7: pathophys, presentation, treatment
Roseola
Ab reaches 100% by 2 years old (infection occurs early)
Infects B and T cells (latent in same, myeloid)
HIGH fever >104 for 3-7 days, adenopathy, red TMs
Seizure risk with fever
Fever ends and diffuse macular rash starts on trunk and moves out
Tx: Gangcyclovir, Forcarnet if resistant
78
HHV-4: diagnosis early and late
EBV
Acute: viral capsid antigen (VCA) and early antigen (EA)
Latent: Epstein-Barr Nuclear Antigen (EBNA)
EBNA-1: links viral to cell genome (closed episome)
EBNA-2: turns on latent genes including cmyc (chr8: Burkitt lymphoma)
Latent in B cells (CD-21)
79
Mono pathophys
```
HHV-4/EBV
Infects B cells, T cells attack and lyse = symptoms
T on B attack = atypical lymphocytes
Adenopathy, pharyngitis, splenomegaly
Heterophile antibody positive (monospot)
```
80
HHV-4 associated malignancy
```
EBV
Post transplant lymphoproliferative disorder
Burkitt lymphoma
B- cell lymphoma
Hodgkin lymphoma (owl's eyes inclusions)
Nasopharyngeal carcinoma
Gastric adencarcinoma
```
81
HHV-8
Kaposi's Sarcoma and B cell lymphoma
HIV/AIDS patients (and transplant)
Dark/violaceous plaques
Latent in B cells (CD-21)
