Quiz 3 Flashcards
In what type of antibody responses do marginal zone B cells participate in?
T-independent antibody responses
Marginal zone B cells can only produce what antibody type?
IgM
Are IgM antibodies low or high affinity when induced by a polysaccharide vaccine?
Low affinity
What chemical change is made to a polysaccharide vaccine to generate a conjugate vaccine?
Which type of vaccine is the most effective, but also tends to elicit the most side effects?
Live attenuated vaccines
How does a live-attenuated vaccine induce immunity? Give an example
Virus strains are selectively grown to be weaker or “attenuated” and can be used to induce an immune response against other strains, due to cross-reactivity
The principle of cross-reactivity allowed for immunity against polio after being administered a cowpox vaccine
Which vaccines are classified as live-attenuated vaccines?
Yellow fever
Measles
Mumps
Rubella
Polio
Varicella
How does a killed or inactivated vaccine induce immunity?
A human virus is used to infect animal cells and then is formalin-fixed (killed); this can induce an immune response
What are some examples of a killed or inactivated vaccine?
Pertussis (Bordetella pertussis)
Paratyphoid fever (Salmonella paratyphi)
Typhus fever (Rickettsia prowezekii)
Cholera (Vibrio cholerae)
Plague (Yersinia pestis)
Influenza
Rabies
How does a toxoid vaccine induce immunity?
Uses a toxin as an antigen to initiate an immune response
What are some examples of toxoid vaccines?
Diphteria
Tetanus
How does a recombinant protein induce immunity?
A DNA encoding antigen is inserted into DNA of a host cell (usually yeast or bactera) in order to mass produce antigen to trigger an immune response
What are some examples of a recombinant protein vaccine?
Hepatitis A
Hepatitis B
Human papillomavirus
How does a polysaccharide vaccine induce immunity?
Bacterial carbohydrate chains isolated from various serotypes can produce a T-cell independent immune response to produce low affinity IgM
What are examples of polysaccharide vaccines?
Meningitis (Neisseria meningitidis)
Bacterial pneumonia (Streptococcus pneumoniae)
What are examples of conjugate vaccines?
Meningitis (Haemophilus influenzae)
How does a conjugate vaccine induce immunity?
A conjugated vaccine is able to induce a T cell response due to the protein attached to the polysaccharide. This allows for formation of a germinal center -> affinity maturation & isotype switching -> high affinity IgG and better overall immunological memory
What is the purpose of adjuvant in vaccines?
To induce inflammation via:
Macrophage activation
Recruitment of inflammatory cells
Cytokine production
*Overall mechanism not well understood
What type of enzyme is reverse transcriptase?
An RNA-dependent DNA polymerase
What is the chief benefit of using ELISA to diagnose HIV?
ELISA is highly sensitive (99.5%)
What is the chief benefit of testing for HIV1/2 or p24 antigen?
Testing is highly specific (>99%)
In what period of HIV infection are false negatives most likely to be detected?
The window period
In what situations would HIV testing be most likely to be falsely positive?
Pregnancy
Influenza vaccine
Autoimmune disease
Where can Mycobacterium avium complex bacteria be found? What symptoms does infections produce? How can it be diagnosed?
Ubiquitous in the environment
Sx
-fever
-night sweats
-weight loss
-diarrhea & abdominal pain
IRIS: lymphadenitis
Dx
-Culture of organism from blood or sterile body site
What is immune reconstitution inflammatory syndrome (IRIS)?
A state of hyperinflammation that can occur during the first few months of treatment of HIV/AIDS patients
What are common symptoms of a Cryptococcus neoformans infection? How is it diagnosed?
Sx
-meningitis (fever, headache, altered mental status)
-elevated CSF pressure (measured w/ lumbar puncture)
Dx
-CSF gram stain & culture
-Cryptococcus antigen (CrAg) in CSF or blood
What significant disease condition is associated with the JC virus?
Progressive multifocal leukoencephalopathy (PML)
How is infection with the JC virus aquired? What symptoms would you expect to see in an infection (PML)? How is it diagnosed?
Reactivation of a common polyoma virus
Sx- Progressive neurologic deficits due to demyelination
-hemiparesis
-ataxia
-seizures
Dx
-MRI- white matter lesions correlate w/ sx
-JC virus PCR in CSF
*Note for poor prognosis, even with ART
What is the seroprevalence of HHV-8 in the US? In MSM? What symptoms would you expect to see in Kaprosi’s sarcoma? How is it diagnosed?
1-5% seroprevalence in the US
20-77% in MSM (much higher than average)
HHV-8 Sx- asymptomatic
Kaprosi’s sarcoma Sx
Non-tender, vascular tumors in skin, lungs, GI tract
Dx
-Biopsy- pathologic identification
What symptoms would you expect to see with an CMV infection? How is it diagnosed?
Sx
-CMV retinitis- destruction of retina leading to blindness
-CMV esophagitis
-CMV colitis
Dx
-Biopsy of affected tissue- pathologic identification
-Serum CMV PCR is non-specific
What are the 2 first line choices for ART combination therapy?
2 NRTI + Integrase Inhibitor
2 NRTI + Protease Inhibitor
What is a reasonable second line choice for ART combination therapy?
2 NRTI + NNRTI
How is drug resistance to ART determined for HIV infections?
HIV genotype
A hepatitis b coinfection with HIV can be treated with what ART drugs?
3TC, FTC, and TDF
What are the brand names of the two combination ART pills used for PrEP or ongoing HIV treatment?
Truvada and descovy
What two drugs make up the combination pill descovy?
FTC/TAF
What two drugs make up the combination pill truvada?
FTC/TDF
What is the brand name of the injectable ART treatment than can be given every two months for PrEP or HIV treatment?
Cabotegravir
Which ART drug is the only one that blocks a human target in the HIV-host cell interaction? What type of drug is it (NRTI, etc.)?
Maraviroc (MVC)
Entry Inhibition RT
What subsections fall under the drug class of reverse transcriptase inhibitors (RTIs)?
Nucleoside analogs (NRTI) and non-nucleoside inhibitors (NNRTI)
What is the TLA for Emtricitabine?
FTC
What is the TLA for Tenofovir?
TDF/TAF
What are the two most notable Nucleoside analogs (NRTIs) used for ART?
Emtricitabine (FTC) and Tenofovir (TDF/TAF)
What is the MoA of NRTIs? What are common side effects? How high is the barrier to resistance?
MoA: NRTIs are prodrugs that are activated by tri-phosphorylation inside the cell. They compete w/ cytoplasmic dNTPs to incorporate into proviral DNA chains. The lack of a 3’-OH leads to chain termination
SE: Mitochondrial toxicity, dyslipidemia
There is a low barrier to resistance w/ multiple common RT mutations
What is the MoA of non-nucleoside inhibitors (NNRTIs)? What are common SE?
MoA: NNRTIs bind near the RT active site to non-competitively inhibit RT
SE: Many SE including teratogenicity
*Not often used
What is the most notable Integrase inhibitor used in ART?
Carbotegravir (CAB)
What is the MoA of integrase inhibitors used in ART? What are notable SE?
MoA: Integrase inhibitors bind to viral integrase and inhibit DNA strand transfer
SE: CPK (creatine phosphokinase) elevation, rash (rare)
What are the two most notable protease inhibitors used in ART?
Darunavir (DRV) and Ritonavir (RTV)
*Ritonavir is a far less effective choice than darunavir, but RTV is added in combinations to improve bioavailability
What is the MoA of protease inhibitors used in ART? What are notable SE? How high is the barrier to resistance?
MoA: PIs do not allow virus to mature after budding
SE: Diarrhea, elevated bilirubin, sulfa moiety, hypercholesterolemia, PPI interactions
High barrier to resistance, very potent
What is the gram-stain and shape of Treponema pallidum?
It is a spirochete that is 5-15um long, it is “technically” gram-negative but stains very poorly
How is syphillis transmitted between people?
Sexual contact w/ a person with an active primary/secondary syphillitic lesion
What are the principle symptoms of primary syphillis?
- Painless chancre
- Regional lymphadenopathy
What are the principle symptoms of secondary syphillis?
- Mucocutaneous macropapular rash (hands & soles of feet)
- Generalized lymphadenopathy
- Patchy alopecia
- Fever malaise
- Condylomata lata
What is the biggest difference between condylomata lata and condylomata acuminata?
Condylomata lata are smoother and flatter than condylomata acuminata
What are the principle symptoms of tertiary syphillis?
- Neurosyphillis (meningitis, tabes dorsalis, paresis)
- CV (arteritis of vasa vasorum)
- MSK (gumma, a soft tumor-like growth of tissues)
What are the non-treponemal diagnostic serology tests used for syphillis?
RPR
VDRL
What are the treponemal diagnostic serology tests used for syphilis?
FTA-ABS
TP-PA
T. pallidum IgG by ELISA
What is the principle treatment for syphillis infection?
Penicillin G
What antiviral treatments are used for HPV? How can warts be treated?
There are no available antivirals for HPV
Tx for warts can involve cytotoxic or surgical means
What is the difference in seroprevalence between HSV-1 and HSV-2
HSV-1 has a seroprevalence of 60-70%
HSV-2 has a seroprevalence of 15-30%
Of HSV-1 and 2 which can remain latent in the dorsal ganglion in the sacral region?
Both HSV-1 and HSV-2
Of HSV-1 and 2 which can remain latent in the trigeminal ganglion?
HSV-1
Of HSV-1 and 2 which is most likely to present with gingivostomatitis in children?
HSV-1
Of HSV-1 and 2 which is most likely to present as vesiculopustular lesions that form coalesced ulcers and can involve the urethra and cervix?
HSV-2
How can a diagnosis of HSV-1 or 2 be made?
Dx
-H&P
-PCR for HSV DNA on skin scrapings
*Don’t use serology to dx active HSV
What treatments are common for HSV1 or 2?
Acyclovir
Valacyclovir
Famciclovir
What type of organsim is Trichomonas vaginalis? What are the common symptoms from infection? How is it diagnosed? What treatments are used?
Protozoan
T. vaginalis is an oval-flagellate that exists only in the trophozoite stage
Sx
-can be asymptomatic
-vaginitis w/ discharge and dysuria (also urethritis & prostatitis)
Dx
-wet mount
-NAAT
Tx
-metronidazole (for both partners in sexual relationship)
What type of organsim is mycoplasma genitalium? What are common symptoms of infection? How is it diagnosed? When should it be considered on a differential?
Tiny bacteria with no cell wall, poor staining if at all
Sx
-2nd most common cause of NGU, cervicitis, PID
Dx
-NAAT (cannot grow in culture)
*M. genitalium should be consiered in cases where pts have urethritis/cervicitis but are chlamydia/gonorrhea negative in testing
What type of organism is haemophilus ducreyi? What are common symptoms of infection? How is it diagnosed? What disease transmission risk is increased by infection?
Gram-negative coccobacillus
Sx
-chancroid
Dx
-Culture
It greatly increases risk of HIV transmission
What treatment can be given for syphillis in the event of a penicillin allergy? Does this treatment change if treating tertiary disease?
Doxycycline
In treatment of tertiary disease, desensitization treatment for penicillin will be given in order to treat w/ penicillin G
What is the Jarisch-Herxheimer reaction? Is it an allergy? What causes the symptoms? What is done to manage symptoms?
A flu-like syndrome that can occur about 8 hours after treatment of patients infected with spirochetes
It is not an allergy
Death of the spirochetes releases toxins triggering pyrexia and other related symptoms
Patients should be educated about reaction possibility; NSAIDs can be used to treat symptoms
What does the presence of urine nitrite suggest on a urinalysis?
The presence of nitrogen-metabolizing organisms
Can you diagnose a UTI based on UA or urine culture alone?
No
Is pyuria (WBCs in the urine) a cause for antibiotic therapy in patients with asymptomatic bacteriuria?
No
Uncomplicated cystitis generally resolves without antibiotics, but which three are often given if necessary?
Nitrofurantoin, TMP/SMX, and Fosfomycin
Uncomplicated pyelonephritis is often treated with which antibiotics?
Fluoroquinolones, TMP/SMX, Beta-lactams (ceftriaxone or cefepime)
What is asymptomatic bacteriuria? How is it diagnosed? How is it treated?
Bacteria in the urine (often colonization, not infection)
Dx
- Positive urine culture ( >10^5 CFU/mL) WITHOUT symptoms
Not necessary to treat in most situations
In what circumstances is treatment of asymptomatic bacteriuria indicated?
Pregnancy
Pre-urology procedure
Renal transplant within 1 month
Neutropenia
What is cystitis? What are symptoms of cystitis? How is it diagnosed? How is it treated?
Bacterial infection of bladder and lower UT
Sx
-dysuria
-increased frequency/urgency of urination
-suprapubic pain
-non-specific sx (fever, N/V, acute delirium)
Dx
-symptoms AND positive urine culture (>10^5 CFU/mL)
Tx
-generally resolves without intervention
What is pyelonephritis? What are symptoms of pyelonephritis? How is it diagnosed? How is it treated?
Bacterial infection of upper UT (ureters and kidneys)
Sx
-fever (38.3 or greater) and chills
-flank or CVA pain
-can present with cystitis and non-specific sx (N/V, dysuria, etc…)
Dx
-symptoms AND positive urine culture (>10^5 CFU/mL)
Tx
-antibiotics (fluoroquinolones, TMP/SMX, beta-lactams)
What significant vector-borne diseases are transmittd by fleas?
Yersinia pestis
What are these pictures indicative of? What disease is this diagnostic of?
Erythema migrans
Lyme disease
When should empiric antimicrobial therapy be initiated in the case of suspected CNS infection?
Immediately
What is the difference in mental status presentation between meningitis and encephalitis?
Meningitis: Typically presents w/ normal mental status
Encephalitis: Typically presents w/ altered mental status
What can be used to differentiate meningitis from encephalitis apart from mental status presentation?
Meningitis
-Kernig sign
-Brudzinski sign
Encephalitis
-focal neurological signs
What is the presentation of a Kernig sign?
As the examiner passively extends the patient’s knees, the patient flexes their neck
What is the presentation of a Brudzinski sign?
As the examiner passively flexes the patient’s neck, the patient flexes hips and knees
What five medications are used as empiric antimicrobial coverage for suspected meningitis?
Ceftriaxone: broad spectrum bacterial coverage
Vancomycin: MRSA
Ampicillin: Listeria (bookends/IC)
Acyclovir: HSV
Dexamethasone: reduce inflammation
What does the NationaL GPS pneumonic stand for? What is it used for?
Neisseria, Listeria, GNR, Pseudomonas, S. pneumoniae
It comprises bacteria that present extra risk to elderly patients
What vector-borne diseases are especially notable for moquito transmission?
West Nile virus
Dengue
Yellow Fever
Zika virus
Malaria
St. Louis encephalitis
Eastern equine encephalitis
What vector-borne diseases are especially notable for transmission by flies?
Leishmaniasis
African trypanosomiasis
What vector-borne diseases are especially notable for transmission by ticks?
Lyme disease
Typhus
Tularemia (Francisella tularensis)
Babesiosis (Babesia microti)
Rocky Mountain Spotted Fever
Human Granulocyte Anaplasmosis (Anaplasma phagocytophilum)
What vector-borne diseases are especially notable for transmission by kissing bugs?
Chagas
What vector-borne diseases are especially notable for transmission by fleas?
Plague
