Weeks 9-12 Flashcards
Transmission: Food and water contaminated with cysts
Site of Infection: Small Intestine
Clinical Presentation: Chronic diarrhea, abdominal pain, bloating,
Epidemology: Transmission: daycare center
Cryptosporidium parvum
- What happens in a type I hypersensitivity reaction?
- What are some common clinical characteristics?
- What activates this response?
- What effector cells respond?
- What are examples of this reaction?
What gene is mutated in IPEX and what is the result of this mutation?
FoxP3 mutation → few to no Tregs produced → increased immune activity
Spectrum:
- Gram(+): Staph (including MRSA)
- Gram(-): E. coli
Clinical:
- Pneumocystis jirovecii
- UTIs
- Staph Soft tissue infection
Trimethoprim/sulfamethoxazole
What is the structure of MHC Class I?
- How many alpha and beta chains?
- Expressed on what ells?
- Binds peptides of what size?
- MHC Class I
- 3 alpha chains and 1 beta chain
- Expressed on all somatic cells
- Binds short peptides (8 to 11 AAs)
How does negative feedback of B-cells occur?
- What cells facilitate this process?
- What cytokines are released by this cell?
- Negative feedback
- T regulatory cells release cytokines that deactivate all lymphocytes
- Cytokine released: IL-10 by T-cells activates ITIM, which blocks signal transduction
Superficial Mycoses
Characterisitics and Examples (4)
Only 1 for SPM exam, 4 total otherwise.
- Characteristics
- Involves outer keratinized layer and noninvasive
- Tinea versicolor (caused by Malassezia fufur)
- Causes hypo/hyper pigmentated lesions
- Lipophilic and can infect intravenously through IVs
- NOT REQUIRED FOR SPM EXAM
- Tinea nigra – caused by Hortaea werneckii and causes lesions
- Black piedra – caused by Piedraia hortae and causes dark nodules on hair shafts
- White piedra – caused by Trichosporon genus and causes white growths around hair of groin
Disease: Whooping Cough (Pertussis)
Presentation, Etiology, Treatment?
Presentation: 1- to 3-week incubation; dry short coughs followed by inspiratory gasp or “whoop”; lymphocytosis
Etiology: Bordetella pertussis
Treatment: Macrolides (Azithromycin)
Chronic Granulomatous Disease
NADPH deficiency leads to macrophage ingesting microorganism without ability to eliminate it
Spectrum:
- Gram(+): Broad coverage
- Gram(-): Broad including Pseudomonas
Clinical:
- Nosocomial aspiration pneumonia (caused by pseudomonas)
4th Generation (Cross BBB)
- Cefeprime
Spectrum:
- Gram(+): Anaerobes (C. diff)
- Gram(-):Anaerobes
- Other: Protozoa
Clinical:
Metronidazole
Wiskott-Aldrich Syndrome
Etiology
Pathphysiology
Symptoms/Clinical Charcaterisitcs
- Etiology: mutation in WASP
- Pathophysiology: decreased actin polymerization in cytoskeleton
- Symptoms: skin bleeding
X-Linked Lymphoproliferative
Etiology
Pathphysiology
Symptoms/Clinical Charcaterisitcs
- Etiology: mutation in SLAM, SAP, or XIAP
- Pathophysiology: decreased NK and T cell activation
- Diagnostic characteristics: inability Epstein-Barr virus (EBV)
Disease: Common Cold
Presentation, Etiology, Treatment?
Presentation: Coryza (runny nose)
Etiology: Rhinovirus or coronavirus
Treatment: Let run natural course
Gram: +
Bacilli
aerobic
- Listeria
- Bacillus
- Corynebacterium
Explain the TH1/ TH2 balance
- Th2 cytokines inhibit Th1 immune responses
- Th1 cytokine promotes macrophages to kill microbials
- Th2 cytokines inhibit microbial killing
- Normally, Th1 > Th2
Transmission: Anopholes Mosquitoes
Site of Infection: Hepatocytes → RBCs → lysed RBCs → anemia
Clinical Presentation:
- Malaria
Epidemology: Africa, South Asia, Tropical Regions
Plasmodium
How does ipilmumab work?
Anti-CTLA-4 (ipilmumab) blocks downregulation of activated T cells
DNA Virus
Capsid Structure?
Naked or Enveloped?
(NAME EXCEPTIONS TOO)
- DNA Viruses
- Capsid: icosahedral
- Exceptions: Pox
- Envelope: none
- Exceptions: Hepatitis B., Herpes viruses, and Pox
- Capsid: icosahedral
Gram: -
Baccili
aerobe
Lactase: -
P’s and S’s
(PSPSPSPS)
-Psuedoonas
-Proteus
-Providencia
-Salmonella
-Shigella
-Serratia
What happens in a type IVb hypersensitivity reaction?
What are some common clinical characteristics?
What activates this response?
What effector cells respond?
What are examples of this reaction?
- Family: Echinocandins
- Target: Cell wall
- MOA:
- Inhibits synthesis of 1,3-beta-D glucan
- Use:
- Candida and Aspergillus
- Clinical:
- Tx: esophagitis, candidemia
Last line of defense against Aspergillus
Caspofungin (IV)
Describe epidemiology of and clinical syndromes from…
Aspergillus - most commonly Aspergillus fumigatus (or Aspergillus-like: Pseudallescheria boydii, Fusarium, Penicllium)
- mold or yeast or dimorphic?
- 3 total syndromes?
-
Invasive Molds
- Septated hyphae with 45 degree branching
- Neutropenia is biggest risk
- Clinical Syndromes
-
Allergic bronchopulmonary aspergillosis (ABPA) – colonization of airways leads to asthmatic symptoms
- Responds to steroids
-
Invasive aspergillosis (IA) – prolonged neutropenia and causes infarcts
- Responds to antifungals
-
Aspergilloma (or fungus ball) – in pre-existing lung cavity
- Responds to surgery
-
Allergic bronchopulmonary aspergillosis (ABPA) – colonization of airways leads to asthmatic symptoms
Spectrum:
- Gram(+): none
- Gram(-): none
- Other: Mycobacteria
Clinical:
- TB
- In combo w/ other drugs b/c of development of rapid resistance
- Accelerates P450 Enzymatic activity of other drugs
Rifampin
What bacteria are associated with the following infection?
- Abdominal Infections (two classes of bacteria)
- Abdominal Infections
- GNRs AND anaerobes
Hyper-IgE Syndromes (HIES)
Etiology
Pathphysiology
Symptoms/Clinical Charcaterisitcs
- Etiology: dominant negative mutation in STAT3 or recessive mutation in DOCK8
- Symptoms: eczema, eosinophilia, two rows of teeth
Avidity versus Affinity
- Avidity – the strength of all of the antigen binding sites combined
- Monomers (IgG) have two binding sites while pentamers (IgM) have ten binding sites
- Affinity – the strength of one antigen binding site
- Antibodies with low affinity binding sites can have an overall high avidity, depending on the number of these binding sites
What is the best test for assessing a classical complement deficiency?
- What will the level of this test be if a complement protein is absent?
- CH50 Test
- If a complement component is absent, the CH50 level will be zero; if one or more components of the classical pathway are decreased, the CH50 will be decreased because lysis in the assay will not occur
Transmission: Food and water contaminated with cysts
Site of Infection: Small Intestine
Clinical Presentation: Chronic diarrhea, abdominal pain, bloating,
Epidemology: Uncommon in USA
Cyclospora cayetanensis
What are the 4 modes of genetic exchange and define each one?
- Modes of genetic exchange: can cause antibiotic resistance
- Transformation – released DNA taken up directly by neighboring cells, integrated by recombination
- Transduction – phages carry DNA to a new cell, either the bacteriophage or pieces of bacterial chromosome
- Conjugation – plasmid or chromosomal DNA is transferred to new cell via sex pilus
- Transposition – gene clusters hop between chromosome, bacteriophage, and plasmid DNAs
Describe epidemiology of and clinical syndromes from…
Mucormycosis – most commonly caused by Mucor (or Zygomyces)
- mold or yeast or dimorphic?
-
Invasive Molds
- Risk factors: DKA, steroids, neutropenia, iron overload
- Diagnosis: non-septated hyphae with 90 degree branching
- Clinical Syndromes
- Rhinocerebral: black necrotic eschars in nasal passage
Describe the events that occur when T cells are activated.
Spectrum:
- Gram(+): MSSA, beta strep, Strep pneumoniae
- Gram(-): E. coli
Clinical:
- Uncomplicated Cellulitis
- Surgery prophylaxis (heart)
1st Generation
- Cefazolin
- Cephalexin
Gram: +
Cocci
aerobic
catalase: -
hemolysis: gamma
enterococcus
- Family: DNA Viruses
- Target: CMV
- MOA:
- Triphosphate that inhibits viral DNA synthesis
- Clinical:
- IV for therapeutics
- PO for prophylaxis
- CMV retinitis
- Very toxic (bone marrow)
Ganciclovir (IV) /Valganciclovir (po)
- What is a type A drug reaction?
- Is it predictable?
- What is it dependent on?
- How common are these?
- Most adverse reactions
- Predictable – related to the pharmacological action of drug
- Dose dependent
- Family: RNA Viruses
- Target: Influenza A & B
- MOA: Neuraminidase Inhibitor – prevents cleavage of HA and sialic acid à blocking release of virus
- Clinical:
- Zanamivir – powder (contraindicated in asthma pts)
- Oseltamivir – oral
Zanamivir/Oseltamivir(Tamiflu)
- What three classes inhibit initiation in protein synthesis?
- Tetracyclines
- Aminoglycosides
- Linezolid
Spectrum:
- Gram(+): MSSA
- Gram(-): H. flu, legionella, moraxella, chlamydia
Clinical:
- Community acquired Resp. tract infection (atypical pneumonia)
- Chlamydia
Azithromycin (Z-pack)
X-Linked Hyper-IgM Syndrome
Etiology
Pathphysiology
Symptoms/Clinical Charcaterisitcs
- Etiology: mutations in CD40L (CD154) gene
- Pathophysiology: defect in class-switching; low levels of all Igs except IgM
- Symptoms: severe and frequent infections
What bacteria are associated with the following infection?
- Non-purulent cellulitis (just erythematous)
- Purulent cellulitis (skin abscesses)
- Cellulitis
- Non-purulent cellulitis (just erythematous)
- Most likely Strep pyogenes
- Purulent cellulitis (skin abscesses)
- Either Staph aureus or Strep pyogenes
- Non-purulent cellulitis (just erythematous)
Spectrum:
- Gram(+):MSSA, beta strep, Strep pneumoniae
- Gram(-): Neisseria meningitidis
- Other: Borrelia burgforferi (Lyme)
Clinical:
- Meningitis
- Lyme Disease
3rd Generation (Cross BBB)
- Ceftriaxone
- Cefotaxime
- Family: DNA Viruses
- Target: Resistant CMV, HSV, VZV
- MOA:
- Pyrophosphate analog that inhibits viral DNA synthesis
- Clinical:
- CMV retinitis
- Very toxic (kidney)
Foscarnet (IV)
What are the three phases of Signal 1?
- How can bacteria resist vancomycin?
- Caused by a change in the peptide component from ala-ala to ala-lactate, which doesn’t allow the drug to bind
Which antibiotics are bactericidal? There are six main types.
- penicilins
- cephalosporins
- vancomycin
- quinilones
- metronidazole
- aminoglycosides
What is the structure of MHC Class II?
- How many alpha and beta chains?
- Expressed on what ells?
- Binds peptides of what size?
- 2 alpha chains and 2 beta chains
- Expressed only on professional APCs (dendritic, B, and macrophage)
- Binds long peptides (11 to 30 AAs)
What causes Type III Bare Lymphocyte Syndrome?
- Type III – loss of both I and II
- Similar to type II
Transmission: Ingestion of undercooked crustaceans
Site of Infection: Migratory from GI to lungs
Clinical Presentation:
- Egg in sputum sample
- Acute infection
- Mimics TB
Lung Flukes
- paragohomus westermari
Describe epidemiology of and clinical syndromes from…
Blastomycosis
- yeast or mold or dimorphic?
-
Endemic Mycoses - DIMORPHIC
- Epidemiology: Ohio and Mississippi River valleys
- Transmission: mold grows in soil → grows as yeast in human
- Patients not contagious in yeast form
- Symptoms: infects lungs/cutaneous lesions
- Diagnosis: histology showing broad-based budding during division
Spectrum:
- Gram(+): staph, strep (MSSA)
- Gram(-): none
Clinical:
- Uncomplicated Cellulitis
Penicillinase – resistant penicillin (methicillin):
- Nafcillin
- Dicloxacillin
- What is a live, attenuated vaccine?
- Do they require a booster?
- What are some examples of this?
- Infectious agents have reduced virulence due to mutations or genetic engineering
- Give strongest response and longest protection
- Examples: MMR, chickenpox
- What is the mechanism of action of fluoroquinolones?
- Inhibits topoisomerase activity of prokaryotes
What happens in a type IVa hypersensitivity reaction?
What are some common clinical characteristics?
What activates this response?
What effector cells respond?
What are examples of this reaction?
What is Signal 2?
Th1 synthesis?
What does it release?
- Synthesis/Differentiation: via IL12/IFN-gamma → activate T-bet
- Releases cytokine: IFN-gamma
What is the antigen receptor-mediated signal transduction in B lymphocytes?
- What transcription factors are activated?
- Signal transduction activated via phosphorylation of Ig-alpha and Ig-beta – co-stimulatory motifs
- Phorsphorylation cascade leads to activation of transcription factors: Myc, NFAT, NF-(kappa)B, and AP-1
- B-cells can also be activated via toll-like receptors (TLRs) or the complement pathway
Transmission: Undercooked fish
Site of Infection: Small intestines
Clinical Presentation:
- Prolonged infection → B12 deficiency (megoblastic anemia)
Diphyllobatrium latum
What bacteria are associated with the following infection?
- Hospital-Acquired Pneumonia (HAP) - 2 types
- Hospital-Acquired Pneumonia (HAP)
- GNRs (Pseudomonas), Staph aureus
Cutaneous Mycoses
Characterisitics and Examples (5)
- Characteristics
- Involves keratinized layer → inflammation of epidermis and upper dermis
- Referred to as tinea and named by location on body (not an organism!)
- Caused by molds called Dermatophytes
- Itchy, flakey, red lesions
- Referred to as ringworm
-
tinea pedis – foot (athlete’s foot)
- Provides portal of entry for Group A Beta Strep (cellulitis)
- tinea cruris – groin (jock itch)
- tinea corporis – general body (classic Ringworm)
- tinua capitis – scalp
- tinea unguium – nails (called onychomycosis)
Describe epidemiology of and clinical syndromes from (3 total syndromes)
Candida (i.e. C. albicans, C. glabrata, C. krusei)
- Yeast or mold or dimorphic?
-
(YEAST)
- Part of normal flora
- Pathogenicity occurs endogenously
- Syndromes
- Mucosal: thrush – cottage cheese-like coating of mouth
- Cutaneous: intertrigo – red rash in between skin folds
- Candidemia: retinitis – fungus in bloodstream seeds in retina (via IV)
- IMPORTANT: positive respiratory samples never indicate pneumonia
Describe epidemiology of and clinical syndromes from…
Pneumocystis (fungi but treated as a protozoan)
Lacks ergosterol and does not respond to anti-fungals
Strictly opportunistic pathogen seen predominately in AIDS
Non-invasive Molds
Dermatophytes (see above)
Trichophyton, Microsporum
Describe epidemiology of and clinical syndromes from…
Cryptococcus (i.e. C. neoformans)
- yeast or mold or dimorphic?
-
(YEAST)
- Prominent capsule that is identified with India Ink
- Strictly opportunistic pathogen seen predominately in AIDS
- Bird feces → lungs → brain
- Syndromes
- Cryptococcal Meningitis
Gram: -
Baccili
anaerobe
B. fragilis
Explain how the TH1/ TH2 balance contributes to different outcomes of a Mycobacterium leprae infection.
- Mycobacterium leprae → Leprosy
- Th2 > Th1 → unable to eradicate infection → lepromatous leprosy (destructive lesions)
Th1 > Th2 → activation of T cells and macrophages → tuberculoid leprosy (less destruction form)
Transmission: Sexual Intercourse
Site of Infection: Vagina, urethra
Clinical Presentation: Usually Asymptomatic, Dysuria from urethritis
Epidemology: Worldwide
Trichomonas vaginalis
Disease: CAP
Presentation, Etiology, Treatment?
Presentation: Fever; cough; sputum; X-ray consolidation
Etiology:
- Normal anaerobes from aspiration
- Typical: Strep pneumoniae
- Atypical: Mycoplasma pneumoniae, Legionella pneumophila, Chlamydophila pneumoniae
Treatment: Sputum sent for Gram stain and culture
Spectrum:
- Gram(+): cocci
- Gram(-): none
Clinical:
- Reserved for VRE & MRSA
Linezolid
- Family: misc.
- Target: n/a
- MOA:
- interferes with nucleic acid synthesis
- Use:
- Candida, Cryptococcal,
- Clinical:
- In meningitis: used with amphotericin initially → fluconazole
- Toxic to bone marrow
Flucytosine (PO)
What happens in a type II hypersensitivity reaction?
What are some common clinical characteristics?
What activates this response?
What effector cells respond?
What are examples of this reaction?
- Family: Azole
- Target: Cell membrane
- MOA:
- inhibits ergosterol synthesis
- Use:
- Aspergillus & Mucormycosis
- Clinical:
- New drug: expanding role
Isavuconazole
What are the 3 immune mechanisms involved in the response to cancer?
- CD8+ T cell-mediated killing of tumor cells
- Tumor presents MHC I + peptide
- Binding stimulates secretion of IFN-gamma (to block tumor proliferation) and perforin/granzymes (apoptosis)
- CD4+ T-cell mediated control of tumor cells
- Macrophage presents MHC II + peptide
- Binding activates macrophage and releases IFN-gamma
- NK cell-mediated killing of tumor cells
- Loss of inhibitory receptor triggers tumor-killing
- Antibody-mediated response to tumor cells
- AB binds tumor proteins → apoptosis
Virus-Cell Interactions (5 TYPES)
- Lytic infection – virus production with cell death
- Abortive infection – infection of non-permissive cells with no infectious virus production
- Persistent infection – long-term virus-cell association with cell survival
- Chronic: virus replicates
- Latent: no replication but some viral gene expression
- Recurrent infection: has latent and lytic periods
- Transformation: oncogenic conversion caused directly by viral gene activities
What is passive therapy underlying immunotherapeutic strategies for cancer?
- Passive therapy – temporary effect (you stop treatment, you stop response)
- Antibody mediated
- Antibodies which lead directly to cell death (trastuzumab)
- Engineered antibodies
- Antibody mediated
X-Linked Gamma Agammaglobulinemia
Etiology
Pathphysiology
Symptoms/Clinical Charcaterisitcs
- Etiology: mutations in Bruton Tyrosine Kinase
- Pathophysiology: failure of B cell maturation past pre-B
- Diagnostic characteristic: no germinal centers in lymph nodes
- Family: Polyenes
- Target: Cell membrane
- MOA:
- Lipophilic molecule that binds to ergosterol
- Use:
- Candida, Cryptococcal,
- Mucormycosis (drug of choice)
- EXCEPT: Pseudallescheria
- Clinical:
- Tx: Meningitis, Neutropenia
- HIGH nephrotoxicity
- Less toxic versions available (Lipid versions)
Amphotercin (IV)
What happens in AERD?
Aspirin Exacerbated Respiratory Disease (AERD)
- If you take aspirin, you get COX blocks → inhibition of PGE2 → increased release of LTs from mast cells → increased inflammatory response
- Diagnostic characteristics: acute dyspnea, nasal polyps and nasal inflammation
- Treatment: aspirin desensitization and “–lukast” drugs (leukotriene modifiers)
Chronic Granulomatous Disease
Etiology
Pathphysiology
Symptoms/Clinical Charcaterisitcs
Diagnosis
- Etiology: mutations in phagocyte oxidase (NADPH Burst)
- Pathophysiology: inability to kill phagocytosed microbes
- Symptoms: recurrent infections
- Diagnosis: NBT Tests (histological view of macrophage activity)
Spectrum:
- Gram(+): none
- Gram(-): broad including multi-drug resistance bacteria (Pseudomonas & Klebsiella)
Clinical:
- LAST RESORT DRUG
- Hearing loss & vertigo
Aminoglycosides
- Gentamicin
- Tobramycin
- Amikacin
Can you mix 2 or 3 antifungals?
Mix 2 or 3 of these Antifungals → Extra toxicity and possible antagonism of MOAs
Gram: +
Cocci
aerobic
catalase: +
coagulase: +
S. aureus
Gram: -
Cocci
aerobic
(5)
- Neisseria gonorrhoeae (diplocooci)
- Neisseria meningitidis (diplococci)
- Haemophilus influenzae
- Bordetella pertussis
-Moraxella catarrhalis
What bacteria are associated with the following infection?
- Community Acquired Pneumonia (CAP)
- generalized pneumonia (1 type)
- atypical pneumonia (3 types)
- post-influenza pneumonia (1 type)
- Community Acquired Pneumonia (CAP)
- Strep pneumoniae
- “Atypical” pneumonias
- Mycoplasma pneumoniae
- Legionella pneumophila
- Chlamydophila pneumoniae
- Staph aureus (post-influenza)
Leukocyte Adhesion Defects (LAD) (3 types)
Etiology
Pathphysiology
Symptoms/Clinical Charcaterisitcs
- Overall pathophysiology: failure to recruit leukocytes to sites of infection
- Symptoms: leukocytosis and recurrent infections early in life
- Types
- Type I
- Etiology: mutation in CD18 gene → defect in integrin
- Diagnostic characteristics: delayed umbilical cord separation
- Type II
- Etiology: abnormality in fucosylation (glycosylation of sialyl Lewis X) → defect in sialyl Lewis X → required for leukocyte-endothelium binding
- Diagnostic characteristics: severe mental/growth retardation
- Type III
- Etiology: mutation in KINDLIN-3 gene → defective platelet aggregation
- Diagnostic characteristic: excessive bleeding
- Type I
What is the alternate pathway and how is it initiated?
- Alternative pathway
- Initiated via C3 convertase formation in addition to Factor B and D binding
Transmission: Insect bite, Swallowing crustaceans
Site of Infection: Blood and Tissue
Clinical Presentation:
- Incubated for one year, then NVD
- Blister formation
Dracunculiasis
Late defects in the complement pathway predispose to:
- Predisposition to Neisseria
- Types of Neisseria
- Meningococcal Meningitis
- Defects in Complement Pathway
- C5b, C6, C7, C8, C9 (any component in MAC)
- Patients with these defects often have reoccurrences because they are unable to use complement pathways to lyse bacteria
- Types of Neisseria
Cold sores/blisters on the genitals or mouth
Herpes Simplex virus
Gram: +
Bacilli
anaerobe
Clostridium difficile/perfringens