QB - MICRO Flashcards
Calicivirus
Viral gastroenteritis
Paramyxovirus
Parainfluenza virus - croup (laryngotracheobronchitis)
RSV (bronchiolitis)
Measles
Mumps
Parvovirus
B19
– Aplastic crises in sickle cell anemia patients; symmetric peripheral arthropathy in females
– Erythema infectiosum (5th disease) in children - “slapped cheek” appearance
– Hydrops fetalis in fetus
Rubella
Maculopapular rash
Occipital and posterior cervical lymphadenopathy
Rash spreads head –> inferiorly –> trunk and extremities
Aspergillus fumigatus
V-shaped (acute angle) branching hyphae
Invasive aspergillosis in IMMUNOCOMPROMISED patients (neutropenics)
Fungus balls in old lung cavities
Allergic bronchopulmonary aspergillosis (ABPA)
Rhizopus & Mucor
NON-SEPTATE hyphae at RIGHT angles
Infect paranasal sinuses
Diabetics, burns, immunocompromised
Facial/periorbital pain, headache, purulent nasal discharge; black eschar on palate or nasal turbinates can be seen; what does organism look like?
Mucor, Rhizopus, Absidia fungi
Only in mold form
Broad, nonseptate hyphase that branch @ wide, often 90o angles
Rx: surgical debridement of necrotic tissue; amphotericin B
What other organisms share similar site of infection as Mucor/Rhizopus?
Invasive aspergillosis
Unlike Mucor&Rhizopus, Aspergillus has septate hyphase that branch at 45 angles (V-shaped branching)
Cryptococcus neoformans
Meningitis + lung infections (AIDS)
Yeast form - spread by respiratory droplets
HIV patient exposed to soil + bird droppings
Yeast has thick polysaccharide capsule - avoids phagocytosis
India ink stain of CSF (wide clear zone around nucleus)
Vibrio cholera
Water-borne gastroenteritis
Oxidase-positive, gram-negative rods
Prefers highly ALKALINE environment
Pts. w/ achlorhydria or been on proton pump inhibitor meds for a long time (e.g. Omeprazole) at risk because stomach loses its acidity –> Cholera passes through stomach to inhabit small intestine
Rhabdoviridae (Rabies)
SS RNA virus - bullet shaped w/ glycoprotein spikes
Binds acetylcholine receptors
Pts infected: agitation, phayngospasm, hypersalivation
Viruses + Cellular Receptor
1. CMV
2. EBV
3. HIV
4. Rabies
5. Rhinovirus
EBV = CR2 (CD21)
HIV = CD4 & CXCR4/CCR5
Rabies = Nicotinic acetylcholine receptor
Rhinovirus = ICAM1 (CD54)
X-linked recessive
Oblivious females will give her boys her x-Linked diseases.
Ocular albinism
Fabry’s
Wiskott-Aldrich
G6PD Deficiency
Hemophilia A&B
Brutton’s agammaglobulinemia
Hunter’s syndrome
Lesch-Nyhan
Duchenne’s dystrophy
Parvovirus B19
Erythema infectiosum (5th disease)
Aplastic crises (sickle cell anemia pts.)
Hydrops fetalis (~20th weeks)
Encapsulated organisms
Neisseria
Haemophilus
Streptococcus pneumoniae
Salmonella
Klebsiella
Group B Strep
L. monocytogenes (Listeria)
Immunocompromised
Unpasteurized milk, undercooked meats, unwashed veggies
Tumbling motility
Vaccine: Capsular polysaccharide
S. pneumoniae
N. meningitidis
H. influenzae
Vaccine: Live attenuated bacteria
BCG - tuberculosis & typhi (outside US)
Measles, mumps, rotavirus, Varicella zoster, SABIN
Vaccine: Killed bacteria
Anthrax
Cholera
Pertussis
Plague (Yersinia pestis)
Vaccine: Inactivated toxin
Diphtheria
Tetanus
Vaccine: Recombinant surface protein
Hep B
Mycoplasma
LACK peptidoglycan wall
Treat w/ Macrolides or Tetracyclines
Spirochetes
Syphilis
Borelia burgdorferi (Lyme disease)
Leptospira
Cold agglutinins
Mycoplasma infection
Positive FTA-ABS
T. pallidum (syphilis)
Can also use VDRL test, RRP test (cardiolipin)
Herpes simplex
VESICULAR skin lesions
DNA virus - enveloped & icosahedral
Neonates - encephalitis
stress brings about HSV-1 outbreaks
TORCH (congenital diseases)
Toxoplasmosis - chorioretinitis, intracranial calcifications (mom exposure to cat litterbox)
CMV - blueberry muffin rash, petechiae (vs. rubella - rubella has PDA, cataracts, deafness)
Rubella - cataracts, blueberry muffin rash
Syphilis - saddle nose, hemorraghing from nose, Hutchinson’s teeth (saber shins)
**Vaginal itching (yeast infection) - discharge
White - Candida
Pseudohyphae and budding yeasts (20C); Germ tubes (37C)
Yellow - Trichimonas
Grey - BV (bacterial vaginosis)
Poxvirus
Only DNA virus that replicates in cytoplasm (all others replicate in nucleus)
dsDNA complex lipid envelope
Only DNA virus that is brick shaped (all other DNA viruses are icosahedral)
Giardia lamblia
Explosive flatulence (chocolate fatty - bad smell!)
Watery diarrhea, recent travels
Crescent shaped protozoa
Entamoeba histolytica
Bloody diarrhea - cysts or trophozoites in stool
Flask shaped ulcers
Klebsiella
Current jelly sputum
Alcohol/hospital
RSV
Pediatrics
HIV
Diagnose babies that has positive ELISA and Western Blot
PCR - how much of the virus is there (confirmatory HIV infection)
Naegleria fowleri
Encephalitis
Missouri, Ohio (Central US)
Histoplasmosis - hides inside macrophages (intracellular yeast)
Pilot’s wheel: paracoiccidiodes
Encapsulated budding yeast: Coccidioides
Trichomonas
Motile trophozoites
Vaginal itching - yellow
Picornavirus
ssRNA virus, nonsegmented naked
Coxsackie
S. aureus
Protein A (keeps itself from being phagocytosed)
causes abscess
Gram +, coagulase +, catalase +
HPV
Owl’s eyes inclusions - CMV
Cowdry - Herpes
Negri bodies - rabies
RSV - paramyxovirus
Kid - pneumonia, bronchiolitis
Group B Strep
Strep Agalactiae
Newborn - nuchal rigidity, bulging fontanelles (meningitis)
Bacitracin resistant
Silver staining cyst
Pneumocystic jirovecii
Sporotrichosis
Roses - gardener
Varicella, Zoster
Sacral root ganglia - HSV2
Trigeminal root ganglia - HSV1
Plamodium falciparum
WORSE malarial type! Southeast Asia
Babesiosis
Northeast US (New England)
Charcoal yeast extract
Legionellla pneumophila
PML
JC virus reactivation
Giant cell oligodendrocytes
De-myelination (white matter)
HIV/AIDS patients
Mumps
Orchitis, parotid glands swollen
Synctia formation - many cells conglomeruate to make a giant cell (avoid antibodies this way)
Pnuemocystis jirovecii
Pulmonary problem in AIDS patient
Clostridium botulinum
Spores - affect babies
Toxin - affect adults
Floppy baby syndrome
Differentiate btwn EHEC, EIEC, Shigella
EIEC - does NOT make a toxin
EHEC - HUS (anemia, thrombocytopenia, acute renal failure) – remember triad!! Doesn’t ferment sorbitol
Shigella - invades host cells (removes adenine from rRNA)
Lecithinase production
Clostridium perfringens
Lecithinase also called alpha toxin or PHOSPHOLIPASE C
destroys RBCs, Leukocytes, endothelial cells –> tissue necrosis “gas gangrene”
Guillain-Barre syndrome (etiological cause)
Demyelinating syndrome of peripheral nerves (ascending muscle weakness/paralysis)
Campylobacter jejuni –> infectious diarrhea
Virus w/ partially double-stranded circular DNA molecule; has RT DNA polymerase; makes intermediate + single-stranded RNA template & dsDNA progeny
Hepatitis B
Viruses with segmented genomes; clinical significance of segmented genome?
Influenza virus (orthomyxovirus)
Rotavirus
Segmented genome allows for genetic reassortment –> genetic shifts occur
contrast w/ genetic drift (via point mutations)
Patient has sharply demarcated salmon-colored plaques - loosely adherent, silvery scale; some nail changes; what other complaints will patient have?
Psoriasis (condition)
associated w/ psoriatic arthritis (potential complication)
How can NSAIDs cause adverse pulmonary symptoms?
Inhibit COX pathway –> shunts over to leukotriene pathway –> precipiate asthma attacks
HIV virus env gene
env gene glycosylated –> gp160
gp160 proteolytically cleaved in ER –> gp120 and gp41
gp120 = viral absorption by binding to CD4 receptor
gp41 anchors gp120 through noncovalent bonds - mediates fusion process
Candidiasis - who is at risk?
HIV+ patients
Diabetes mellitus
Cancer
Asthma patients on oral/inhaled steroids
Systemic antibiotic therapy
Dentures
Produces potent exotoxin associated w/ cardiac and neural toxicity
C. diphtheriae –> bacterial toxin-mediated axonal damage
also causes pseudomembranous pharyngitis
Difference btwn EHEC O157:H7 and rest of E. coli
EHEC unable to ferment sorbitol on MacConkey agar & lacks glucuronidase
EHEC
hemorrhagic colitis (undercooked hamburger meat)
Shiga-like toxin inactivate 60S ribosomal subunit
HUS – thrombocytopenia, microangiopathic hemolytic anemia, renal insufficienct (uremia)
ETEC toxins
LT and ST
Bacteria toxins that activate adenylate cyclase (cAMP)
Pertussis toxin
Edema factor (B. anthracis)
Heat labile toxin (ETEC)
C. jejuni enterotoxin (Campylobacter jejuni)
Heat labile enterotoxin (Bacillus cereus)
Choleragen toxin (V. cholerae)
Increase cAMP –> increased secretion of Na+, Cl-, and H20 into intestinal lumen –> diarrhea
Bacteria toxins that activate guanylate cyclase (cGMP)
Heat stable toxin (ETEC)
Y. enterocolitica enterotoxin (Yersinia enerocolitica)
Increase intracellular cGMP –> watery diarrhea + electrolyte loss
Bacteria toxins that inactivate EF-2
Diphtheria toxin
Exotoxin A (Pseudomonas aeruginosa)
Inhibit protein synthesis (catalyze ADP-ribosylation of EF-2 –> protein inactivated)
Bacteria exotoxin that disrupts cytoskeleton
Clostridium difficile –> depolymerize actin –> cell death
Mechanism by which Shigellosis initiates infection
Specificity to M cells in Peyer’s patches in ileum (endocytosis)
S. sonnei common in US
Ulceration w/ hemorrhage & diarrhea
Common cause of otitis media; vaccine against what part of bacteria?
H. influenzae common cause of otitis media
Vaccine against polysaccharide capsule – strains that do not produce capsule = nontypable; Nontypable is not susceptible to Hib vaccine
Blastomycosis dermatitidis
Great Lakes, Missisippi, Ohio River
found in mold form in soil and animals (dogs, horses)
flu-like illness: pleuritic chest pain, hemoptysis
pulmonary blastomycosis –> granuloma formation
Virulence factor of Mycobacterium tuberculosis
“Serpentine” pattern - prescence of cord factor
Cord factor = mycoside = two mycolic acid molecules bound to disaccharide trehalose
Cord factor inactivates neutrophils, damages mitochondria, induces release of tumor necrosis factor
Superantigens of Staph and Strep; mechanism?
Widespread T cell activation - bind nonspecifically to T cell receptors and CD4+ T cells
ETEC
Campylobacter jejuni
Vibrio cholera
Yersinia enterocolitica
Mechanism of pathogenesis?
Release exotoxins –> electrolyte transport
cAMP –> active efflux of Na+ and Cl- –> water follows –> diarrhea
Clostridium perfringens
Release alpha-toxin or phospholipase C –> degrades cell membrane phospholipids –> cell destruction
Prophylactic Rx for M. tuberculosis or positive PPD conversion
Isoniazid
Rifampin is prophylactic Rx for what organisms?
Neisseria meningitidis
H. influenzae
Penicillin is treatment for which organisms?
Treponema (syphilis)
Neisseria (gonorrhea)
Gram + bacteria
TMP-SMX is prophylactic treatment for what organisms?
Pneumocystis jiroveci - pneumonia (fever, non-productive cough)
Toxoplasma gondii
Prophylactic treatment for Mycobacterium avium complex (MAC)
Opportunistic pathogen causing disseminated disease in HIV+ patients
Azithromycin
Legionella pneumonia
High fever
Bradycardia
Watery diarrhea - due to ingestion of organism via contaminated water source
Hyponatremia**
Gram stain – see A LOT of neutrophils but very little organisms (intracellular organism)
Unilobar lung infiltrate –> consolidation
Organism stains positive in mucicarmine stain; what is stain used for and what fungus stains positive?
Stains polysaccharide capsule of Cryptococcus neoformans (virulence factor)
Organism is round yeast cells w/ narrow-based buds
Cysteine-tellurite agar
C. diphtheriae –> black colonies
Thayer-Martin VCN medium
Neisseria species
VCN = vancomycin, colistin (polymyxin), nystatin
Aseptic meningitis & herpangina (painful mouth blisters) in children
Coxsackie virus
Hemiparesis
Visual field defects (hemianopsia)
Cognitive impairment
PML due to JC virus
Cause of aplastic crises in sickle cell anemia pts.
Causes hydrops fetalis in fetus
Parvovirus B19
Heterophil antibody-negative mononucleosis
CMV
Contrast w/ heterophil antibody-positive (Mono-spot positive) mononucleosis: EBV
S. haematobium
vs. S. mansoni
vs. S. japonicum
S. haematobium: urinary schistosomiasis
S. mansoni: intestinal schistosomiasis
S. japonicum: hepatic schistosomiasis
Rabies virus reservoir in US
Bats
Hydatid cyst in humans – following ingestion of food; what is intermediate host?
Echinococcus granulosus (dog tapeworm)
Sheep are intermediate host
