Micro 3 Flashcards
What are the envelope proteins of HIV
gp41 (transmembrane glycoprotein) and gp120 (docking glycoprotein) whic hare acquired through budding from host cell plasma membrane
What is p24 in HIV?
Capside protein
What is p17 in HIV?
Matrix protein
HIV Genome?
diploid (2 molecules of RNA)
3 genes of HIV and products
env (gp160=gp120 and gp41) gp120 attaches to CD4 cell and gp41 is for fusion and entry
gag (p24): capsid protein
pol is reverse transcriptase, aspartate protease, integrase
Replication of HIV genome
reverse transcriptase makes dsDNA which integrates into the host genome
What receptors does virus bind to?
On CD4+ cells: CD4 and CCR5 (early) or CXCR4 (late) co-receptor
On macrophages: CCR5 and CD4
What people have immunity
CCR5 negative homozygotes. heterozygotes have a slwoer course
What are the rule out and rule in tests of HIV?
Rule out is ELISA because of high sens, low spec.
Rule in is Western blot because of high spec., low sens.
What are the thresholds for CD4 counts
Normal is 500-1500 cells/mm3.
AIDS is either <14%
Where can you find false positives and false negatives in HIV?
Lots of false positives in babies because of anti-gp120 crossing the placenta.
False negatives in first 1-2 mo. of HIV infection
Natural history of HIV mnemonic
4 F stages: Flu-like (acute), feeling fine (latent), falling count, final crisis
Where does HIV replicate in latent phase
Lymph nodes
What kind of cancer increases with HIV?
Non-Hodgkin lymphoma (large cell type) Often on oropharynx (waldeyer ring)
HIV low-grade fevers, cough, hepatosplenomegaly, tongue ulcer
Histoplasma capsulatum (only pulmonary sxs in immunocompetent hosts)
Derm and HIV
Candida, hairy leukoplakia, superficial vascular proliferation, superficial neoplastic proliferation of vasculature
What causes vascular proliferation
Nonmalignant: Bartonella henselae (causes bacillary angiomatosis)
Malignant: HHV-8 (Kaposi’s sarcoma)
HIV diarrhea
Cryptosporidium
Neurologic and HIV
Abscesses, dementia, encephalopathy, meningitis, retinitis
HIV abscess
Toxo
HIV demenia
Directly associated with HIV
HIV encephalopathy
JC virus reactivation (PML)
HIV meningitis
Cryptococcus neoformans
HIV retinitis
CMV
HIV associated cancers and pathogen
Non-Hodgkin lymphoma, Primary CNS lymphoma (both associated with EBV)
Squamous cell carcinoma of anus (HPV)
Difference between toxo and Lymphoma
Toxo has multiple ring-enhancing lesions
HIV respiratory issues
Interstitial pneumonia invasive aspergillosis PCP Typical PNA Tuberculosis like disease
Biopsy of bartonella vs. kaposis
Bartonella has PMN inflammation, Kaposi’s has lymphocytic inflammation
Normal prion protein name and conformation
alpha-helical prion protein (PrP^c) to pathological Beta-pleated form (PrP^sc) that is transmissible
Sporadic spongiform encephalopathy
Creutzfeldt-Jakob disease
Inherited prion disease
Gerstmann-Straussler-Scheinker
Acquired prion disease
Kuru
Day-care diarrhea
Yersinia enterocolitica
Salmonella and shigella lactose
Both NONfermenters
PNA in neonates (<4 wks)
Group B strep, E. coli
Most common PNA in children 4 wk-18 yr
RSV, Mycoplasma, C. trachomatis (infants-3yr), C. pneumoniae (school children), S. pneumo Runts May Cough Chunky Sputum
PNA Adults (18-40 yrs)
Mycoplasma, C. PNA, S. PNA
PNA Adults (40-65 yrs)
S. pna, H. flu, anaerobes, viruses, mycoplasma
PNA elderly
S. pneumo, flu, anerobes, h. flu, gram negative rods
Congenital Toxo
Classic triad: Chorioretinitis, hydrocephalus, and intracranial calcifications
Congenital Rubella
Classic triad: PDA (or pulm. artery hypoplasia), cataracts, and deafness +/- “blueberry muffin” rash
Congenital CMV
Hearing loss, seizures, petechial rash, “blueberry muffin” rash
Congenital HIV
Recurrent infections, chronic diarrhea
Congenital HSV-2
Encephalitis, herpetic lesions
Congenital Syphilis
Often stillbirth, hydrops fetalis; if child survives, facial abnormalities: notched teeth, saddle nose, short maxilla. Saber shins, CN VIII deafness
What is a saber shin
Anterior bowing of the tibia
What is hydrops fetalis?
Fluid accumulation in at least two fetal compartments like the pleural space, pericardium, peritoneum, subQ tissues
Fifth disease name and cause
Erythema infectiosum (Parvo B19) Slapped cheeks
Roseola cause
HHV-6
Roseola rash presentation
Macular rash over body after several days of high fever, can have febrile seizures, usually in infants
Measles rash
Paramyxovirus; begins at head and mvoes down; rash preceded by cough, coryza, conjunctivitis and blue-white Koplik spots on buccal mucosa
Rubella rash
Rash at head and moves down; leads to fine truncal rash; postauricular lymphadenopathy
Scarlet fever rash
Erythematous, sandpaper-like rash with fever and sore throat
Parvo B19 congenital
Can cause hydrops fetalis
Genital Chlamydia serotype
D-K
Lymphogranuloma venereum cause
C. trachomatis L1-L3
Strawberry cervix
Trichomoniasis
Lymphogranuloma venereum presentation
Infection of lymphatics; painless genital ulcers, painful lymphadenopathy (i.e. buboes)
Chancroid presentation
Painful genital ulcer, inguinal adenopathy
Fitz-Hugh-Curtis syndrome
Infection of liver capsule and “violin string” adhesions. Classically associated with gonorrhea, but actually more often due to Chlamydia
Unimmunized children neurologic disease
Meningitis due to HiB. It colonizes nasopharynx.
order of prevalence of encapsulated organism infection
S. pneumo»_space;> HiB > meningococcus
MOA trimethoprim
Inhibits dihydrofolate reductase
MOA of sulfamethoxazole (sulfonamides)
Inhibits PABA to DHF
What targets DNA topoisomerases
Fluoroquinolones and quinolones
MOA of nalidixic acid
Quinolone inhibits DNA topoisomerase
What are Streptogramins
Quinupristin and Dalfopristin: They inhibit 30S ribosome, used in treating vancomycin resistant s. aureus and vancomycin resistant enterococcus.
What are penicillin binding proteins
Transpeptidases
Penicillin bactericidal or bacteriostatic
Bactericidal (for gram-positive cocci and rods, gram-negative cocci, and spirochetes.
Penicillin G, V use
Gram positivies like pneumococcus, s. pyogenes, actinomyces, and meningococcus, and syphilis
Penicillin side effects
allergy, hemolytic anemia
Aminopenicillins susceptible bacteria
H. flu, e. coli, listeria, proteus, salmonella, shigella, enterococci.
Aminopenicillin mnemonic
ampicillin/amoxicillin HELPSS kill enterococci (H.flu, E. coli, Listeria, Proteus, Salm., Shig., enterococci
What are the penicillinase resistant penicillins
Oxacillin, nafcillin, dicloxacillin. They are narrow spectrum.
What makes penicillinase resistant penicillins resistant to penicillinase?
Bulky R group prevents access to beta-lactam ring
Side effects of oxacillin, etc. ?
Interstitial nephritis, hypersensitivity reactions
Antipseudomonals description
Extended spectrum: Pseudomonas and gram-negative rods, susceptible to penicillinase
What organisms are not typically covered by cephalosporins?
LAME: Listeria, Atypicals (Chlamydia, Mycoplasma), MRSA, and Enterococci.
Cephalosporins description
Less susceptible to penicillinases. Bactericidal
Name 1st gen. cephalosporins and targets
Cefazolin, cephalexin: PEcK; Proteus, E.coli, Klebsiella.
2nd gen cephs. and targets
Cefoxitin, cefaclor, cefuroxime: HEN PEcKS: H.flu, enterobacter aerogenes, Neisseria, Proteus, E. coli, Kleb, Serratia
3rd gen cephs. and targets
Ceftriaxone, cefotaxime, ceftazidime: serious gram-negative infections resistant to other beta-lactams:
Ceftriaxone for what infections specifically
Meningitis and gonorrhea
Ceftazidime indication
Pseudomonas
4th gen cephs. and targets
Cefepime: active against pseudomonas and gram-positives
5th gen cephs. and targets
Ceftaroline; broad gram-positive and gram-negative, including MRSA, no Pseudomonal coverage
Cephalosporin side effects
Vit. K deficiency, low cross-reactivity with penicillins, increases nephrotoxicity of aminoglycosides.
Monobactams MOA
Aztreonam: resistant to beta-lactamases, binds penicillin-binding protein 3. Synergistic with aminoglycosides. No cross-allerginicity with penicillins.
Aztreonam clinical use
Gram-negative rods only: no activity against gram-positives or anaerobes. Penicillin-allergy patients and renal insufficiency who can’t tolerate aminoglycosides
Aztreonam side effects
Usually nontoxic; occasional GI upset
Carbapenems examples
Imipenem, meropenem, ertapenem, doripenem
Imipenem MOA
Borad-spectrum, beta-lactamase resistant carbapenem. Always give with cilastatin (inhibitor of renal dehydropeptidase I) to decrease inactivation of drug in renal tubules. “with imipenem, the kill is lastin with cilastatin’
Ertapenem activity
Limited pseudomonal coverage
Carbapenems clinical use
Wide spectrum: Gram-positive cocci, gram-negative rods, and anerobes.
Carbapenem side effects
GI distress, skin rash, seizures at high plasma levels
Meropenem benefits
Decreased risk of seizures and stable to dehydropeptidase I
Vancomycin MOA
Inhibits cell wall peptidoglycan formation by binding D-ala D-ala portion of cell wall precursors. Bactericidal.
Vancomycin clinical use
Gram positives only: MRSA, enterococcus, C. diff
Vancomycin side effects
NOT trouble free: nephrotoxicity, ototoxicity, thrombophlebitis: red man syndrome (give benadryl to prevent)
Vancomycin resistant MOA
Turn D-ala D-ala to D-ala D-lac
Ribosomal antibiotic mnemonic
Buy AT 30, CCEL at 50. Aminoglycosides, Tetracyclines, Clindamycin, Chloramphenicol, Erythromycin (Macrolides), Linezolid
Are protein synthesis inhibitors bactericidal or bacteriostatic
All are bacteriostaic except for aminoglycosides that are bactericidal. linezolid is variable.
Linezolid MOA
Blocks ribosome formation
Aminoglycosides MOA
Binds to 30S, prevents initiation complex formation
Chloramphenicol MOA
Binds 50S, blocks peptidyl transferase
Macrolides and Clindamycin MOA
Bind 50S, blocks translocation
Tetracyclines MOA
Binds 30S, blocks A-site tRNA binding
Aminoglycosides examples
Gentamicin, neomycin, amikacin, tobramycin, streptomycin
Aminoglycosides MOA
block formation of initiation complex and cause misreading of mRNA, also blocks translocation. Require O2 for uptake; cannot be used against anaerobes
Aminoglycosides clinical use
Severe gram-negative rod infections. Synergistic with beta-lactams.
Neomycin use
For bowel surgery
Aminoglycosides toxicity
Nephrotoxicity (with cephalosporins), Neuromuscular blockade, Ototoxicity (especially with loop diuretics), Teratogen
Aminoglycosides resistant MOA
Bacterial transferase enzymes inactivate the drug by acetylation, phosphorylation, or adenylation
What is the integrase inhibitor for HIV
Raltegravir