Flashcards - Micro
superantigen
interacts with MHC on APCs/T-cells –> causes widespread activation of T-cells (IL2) and macs (IL-1/TNF)
Bradyzoites
Toxoplasma
P fimbriae
E. coli - allows adhesion ot uroepithelium
Cowdry Type A
HSV
Cowdry Type B
Adenovirus
ballooning degeneration, fine cytoplastic protein granules
acute hepatitis (HBV, HAV)
lymphoid aggregates in portal tracts
HCV
M Protein
Streptococcus pyogenes/Scarlet fever - binds factor H, inactivaes C3-convertase
Protein A
staph aureus - binds IgG Fc, preventing opsonization
pyocynin
Pseudomonas aeruginosa - green pigment
exotoxin A
inhibits elongation factor 2 (EF-2), Pseudomonas aeruginosa
tetanus toxin
blocks release of inhibitory neurotransmitters in Renshaw inhibitory neurons
shiga toxin/EHEC
inactivates 60S ribosomal subunit - apoptosis
choleragen and E. coli heat labile toxin
activates adenylate cyclase - increase cAMP, induces secretion of NaCl
e. coli heat stable toxin
activates guanylate cylase to produce GMP, inhibits resorption of NaCl
4 bacteria that produce exotoxins that increase cAMP
cholera, anthrax, Montezumas revenge (ETEC), pertussis
catalase +/-
Staph/Strep
coagulase +/-
S. aureus/S epidermidis (novobiocin sensitive), S. saprophyticus (novobiocin resistant)
gram + rods
clostridium, listeria, bacillus, corynebacterium
vanA
enterococcus - D-alanine-D-lactate - low affinity for vancomycin
Chocolate agar
H. influenzae - meningitis w/ ceftriaxone, mucosal w/ amox
Thayer-Martin agar
N. gonorrhoeae, N. meningitidis (capsule, maltose fermenter)
Bordet-Gengou agar, Regan-Lowe medium
B. pertussis
Löwenstein-Jensen agar
M. tuberculosis
Eaton agar
M. pneumoniae
Lactose-fermenting enterics
MacConkey agar - Fast - klebsiella, e. coli, enterobacter; Slow - citrobacter, serratia
Eosin–methylene blue (EMB) agar
E. coli
Charcoal yeast extract agar buffered with cysteine and iron
Legionella
Sabouraud agar
Fungi
thiosulfate-citrate-bilesalts-sucrose (TCBS) agar
V. cholerae
Ziehl-Neelsen (carbol fuchsin)
Acid-fast bacteria (Nocardia, Mycobacteria), protozoa (Cryptosporidium oocysts).
broad, nonseptate hyphae at 90degrees
Mucormycosis
India ink
Cryptococcus neoformans
Silver stain
Fungi (e.g., Pneumocystis), Legionella, Helicobacter pylori.
Giemsa stain
Chlamydia, Borrelia, Rickettsia, Trypanosomes, Plasmodium.
tumbling motility at 25C, rocket tails
listeria
comma shaped oxidase positive bugs
c. jejuni (grows in 42C), v. cholerae (grows in alkaline), h. pylori (urease)
EHEC
O157:H7 - shiga-toxin - HUS
ETEC
travelers diarrhea - enterotoxin
EIEC
similar to Shigella
mucoid colonies, dark ‘currant jelly’ sputum
klebsiella - polysaccharide capsules
salmonella treatment
no antibiotics, can prolong duration
catalase, oxidase and urease positive gram negative rod
H. pylori - PPI + clarithromycin + amoxicillin/metronidazole
Q fever
coxiella burnettii - cattle/sheep amniotic fluid - pneumonia, culture neg endocarditis
oxidase positive gram negative rod
pseudomonas aeruginosa
oxidase negative gram negative rod non lactose fermenting - does not produce H2S
shigella
oxidase negative gram negative rod that produces H2S
salmonella, proteus, yersinia
gram positive anaerobe forming yellow “sulfur granules”
actinomyces - oral flora - penicillin
acid fast gram-positive aerobe
nocardia - found in soil - sulfonamides
gold pigment on sheep blood agar
staph aureus (gold)
gray to black on potassium-tellurite plate
C. diphtheriae
biofilm forming
coag negative - staph epidermidis
encapsulated bacteria
strep pneumo, h. flu B, N meningititis, E coli, salmonella, klebsiella, GBS
PAS+
stains glycogen - T whipplei
MAC prophylaxis
azithromycin
catalase positive organisms
NoPLACESS - nocardia, pseudomonas, listeria, aspergillus, candida, e. coli, staph, serratia
urease positive organisms (7)
Cryptococcus, H pylori, Proteus, Ureaplasma, Nocardia, Klebseilla,S. epidermidis, S. saprophyticus
c. perfringens toxin
lecinthinase (phospholipase C/alpha toxin) - gas gangrene
diphtheria toxin
AB exotoxin - inactivates EF-2 - inhibits protein synthesis, Corynebacterium diptheriae
cytoplasm with metachromatic granules that saine with aniline dyes/methylene blue
C diptheriae
maltose +/- diplococci
N. meningitidis/N. gonorrhoeae
Toxin B/cytotoxin
disrupts cytoskeleton - C.diff
adenylate cyclase activating toxins organisms
pertussis, anthrax, ETEC (heat labile), campylobacter, cholera, bcereus
guanylate cyclase activating toxin organisms
ETEC (heat stable), yersinia enterocolitica
pregnant HIV prophylaxis
Ziduvadine
disc-shaped yeast on methenamine silver of lung tissue, acellular, foamy material
pneumocystis jiroveci
Negri body, bullet shaped
Rabies - retrograde axonal migration from Ach receptor
IgA protease
strep pneumo, h. flu, N. gonorrhea and meningitidis
basophilic clusters on intestinal mucosa cells, oocytes
cryptosporidiosis
spindle cells with blood vessel proliferation
kaposi’s sarcoma HHV-8
trophozoites with RBCs
entamoeba histolytica - bloody diarrhea
endotoxin lipid A
Enterobacteriaceae - part of LPS, activates macrophages - septic shock
Councilman bodies
acidophilic (pink on H&E) apoptotic hepatocytes - acute viral hepatitis
Candida defense
T-lymphocyte mediated for superficial, neutrophil mediated for systemic
viral serum sickness
Hepatitis B
pyrrolidonyl arylamidase (PYR)+, beta-hemolytic, gram-positive cocci
strep pyogenes
sporothrix schenckii
rose prick - lymphatic nodules - round/cigar shaped budding yeast - treat with itraconazole or potassium iodide
coccidioides
southwest US - pulmonary - thick walled spherules with endospores
histoplasma capsulatum
ohio/mississippi valleys, bats, bird droppings - pulmonary (granulomas with calcifications) - oval yeast cells within macrophages
blastomyces dermatitidis
ohio/mississippi valleys, soil - pulmonary (pneumonia) - doubly refracted wall, broad based bud
paracoccidioides brasiliensis
central/south america - mucocutaneous ulcers - cells covered in budding blastoconidia - captains wheel
cryptococcus neoformans
soil/pigeon droppings - meningitis, pulmonary - budding yeast forms with thick capsules
budding yeast in “captain’s wheel”
paracoccidioidomycosis
candida albicans
germ tubes/true hyphae at 37C
legionella
intracellular gram-negative - pneumonia, diarrhea, hyponatremia
cold agglutinins
EBV, mycobacteria
lipooligosaccharide
N. meningitidis - levels correlated with mortality
india ink/mucicarmine stain, encapsulated yeast with narrow-based budding, “soap bubble”, latex agglutinating
cryptococcus neoformans
osmium tetraoxide
stains fat - fat embolus in lung tissue
tinea versicolor
Malassezia (pityrosporum) - acids from degradation of lipids damage melanocytes
H. influenza b growth medium
blood agar with X (hematin) and V (NAD+) factor
naegleria fowleri
freshwater lakes - rapidly fatal meningoencephalitis - amphotericin B
trypanosoma brucei
african sleeping sickness - tsetse fly - recurrent fever - suramin (blood), melarsoprol (CNS)
toxoplasma gondii
tachyzoite on biopsy - sulfadiazine + pyrimethamine
babesiosis
“maltese cross” - tick borne - atovaquone + azithromycine
trypanosoma cruzi
chagas disease - reuviid bug (kissing) - benzidazole or nifurtimox
bendazoles
treat nematodes(roundworm) - enterobius vermicularis, ascaris lumbricoides, strongyloides stercoralis, ancylostoma duodenale, nevator americanus, trichinella spiralis
taenia solium
undercook pork - intestinal infection, cysticercosis, neurocysticercosis - praziquantel
echinococcus granulosus
dog feces, sheep - hyatid cysts in liver - anaphylaxis if released - inject with ethanol/hypertonic saline, albendazole
praziquantel
tapeworms (taenia solium, diphyllobothrium latum) and flukes (schistosoma, clonorchis sinensis)
live attenuated vaccines (7)
smallpox, yellow fever, rotavirus, chickenpox, sabin, MMR, influenza (intranasal)
killed vaccine (4)
rabies, influenza (injected), salk polio, HAV
aspiration pneumonia bacteria
anaerobes - peptostreptococcus, fusobacterium, prevotella, bacteroides
typhoid fever
salmonella typhi - fever, watery diarrhea, salmon-colored rose spots, hepatosplenomegaly, GI bleeding
newborn meningitis
listeria, e. coli, GBS
elderly meningtitis
S. pneumoniae, gram negative rods, listeria
IV drug abuse osteomyelitis
pseudomonas, candida, s. aureus
fitz-hugh-curtis syndrome
PID –> liver capsule infection and adhesions
CR2 (CD21)
EBV - interacts with gp350
CD4/CXCR4/CCR5
HIV
ICAM1
rhinovirus
Group A strep
bacitracin sensitive - S. pyogenes
Group B strep
bacitracin resistant - S. agalactiae
d-glutamate aminoacid antiphagocytic capsule
Bacillus anthracis
encapsulated bile soluble optochin sensitive lancet-shaped, gram-positive cocci in pairs
Strepococcus pneumoniae
non-encapsulated optochin resistant alpha hemolytic
viridans strepococci
bean-shaped, gram-negative cocci in pairs
N. meningitidis
B. anthrancis toxin
adenylate cyclase –> massive increase in cAMP
Bordetella pertussis toxin
adenylate cyclase –> massive increase in cAMP
most common HIV resistance
pol gene mutation - resistance to standard protease inhibitors; Env mutation - escape from host neutralizing antibodies
HIV gp41 protein
env - fusion protein - enfurviritide
HIV gp120 protein
env - target cell attachment - CCR5 on macs, CXCR4 on T-cells
HIV p17 protein
gag - matrix protein
heteropil antibodies
Monospot - detects EBV
parvovirus B19 binding antigen
erythrocyte P antigen
DNA viruses
double stranded, linear, icosahedral, replicate in nucleus
Papillomavirus (HPV)
dsDNA, non-enveloped, circular
Adenovirus
dsDNA, non-enveloped, linear
Hepadnaviridae (HBV)
dsDNA, enveloped, circular
herpesvirus
dsDNA, enveloped, linear - HSV1, HSV2, VZV, EBV, CMV, roseola, kaposi(8)
Parvoviridae (B19)
ssDNA, non-enveloped, linear - erythema infectiosum (5th disease) - “slapped cheek”
reovirus (rotavirus)
dsRNA, non-enveloped, linear, icosahedral
Pircornaviridae
ssRNA+, non-enveloped, icosahedral - polio, echo, rhino, coxsackie, HAV (PERCH)
calcivirus (norovirus)
ssRNA+, non-enveloped, icosahedral
Flaviviridae
ssRNA+, enveloped, icosahedral - HCV, yellow, dengue, west nile
Deltaviridae (HDV)
ssRNA-, enveloped, helical
Hepeveridae
ssRNA+, enveloped, icosahedral - HEV
retrovirus
ssRNA+, enveloped, icosahedral - reverse transcriptase - HIV, HTLV
Togaviridae
ssRNA+, enveloped, icosahedral - Rubella, eastern/western equine encephalitis
coronavirus
ssRNA+, enveloped, helical - “common cold”, SARS
filovirus (ebola)
ssRNA-, enveloped, helical
orthomyxovirus
ssRNA-, enveloped, helical, segmented - influenza
rhabdovirus (rabies)
ssRNA-, enveloped, helical, segmented
paramyxovirus
ssRNA-, enveloped, helical - Mumps, RSV, measles, parainfluenza
segmented viruses
RNA viruses - bunyaviruses, orthomyxoviruses, arenaviruses, reoviruses (BOAR)
negative strand viruses
needs own RNA-dependent RNA polymerase - arenavirus, bunyavirus, paramyxovirus, orthomyxovirus, filovirus, rhadovirus
exanthem subitus
roseola/HHV-6 - rose colored macules after several days of high fever
hand-foot-mouth disease
coxsackievirus type A - oval shaped vesicles on palms/soles, oral mucosa
rash from head moving down
measles - cough, coryza, conjunctivitis, koplik spots
pale coalescing macules from head moving down
rubella/German measles
infant: PDA, cataracts, deafness, blueberry muffin rash
rubella
infant: hearing loss, seizures, petechial rash, blueberry muffin rash, periventricular calcifications
CMV
infant: recurrent infections, chronic diarrhea
HIV
infant: encephalitis, herpetic lesions
HSV 2
infant: stillbirth, hydrops fetalis, notched teeth, saddle nose, short maxilla, saber shins, CN8 deafness
syphillis
Zidovudine
nucleoside reverse transcriptase inhibitor - bone marrow toxicity, anemia
Oseltamivir
neuraminidase inhibitor - virus unable to release from cell
Indinavir
protease inhibitor - lipodystrophy, hyperglycemia, P450 inhibitor
Raltegravir
integrase inhibitor
Foscarnet
CMV infection - nephrotoxicity - hypoCa, hypoMg, hypoK
transformation
naked DNA fragment uptake
transduction
viral-mediated DNA transfer
conjucation
transfer with sex pili
transposition
plasmid jumping
acid-fast bacteria that grows optimally at 41C
mycobacterium avium complex
listeriolysin
lyses through vacuolar membrane into cytosol
sorbitol non-fermenting, no glucuoronidase production E. coli
EHEC O157:H7
toxin A
C. diff enterotoxin - inactivate Rho-regulatory proteins - disrupts actin cytoskeleton/tight junctions
toxin B
C. diff cytotoxin
schistosoma haematobium
from snails - expelled in urine
Malaria
p. falciprum - daily fever
p. vivax, ovale - periodic fever
acute bronchopulmonary aspergillosis (ABPA)
complicates asthma, transient recurrant pulmonary infiltrates
intracranial calcifications
neonatal toxoplasmosis
beta hemolytic strep breakdown
B-BRAS - bacitracin - group b resistant, group a sensitive
alpha hemolytic Strep breakdown
OVERPASS - optochin - viridins resistant, pneumo sensitive
coag negative Staph breakdown
No STRESS - novobiocin, saprophyticus resistant, epidermidis sensitive
gram negative bacilli breakdown
daCLB - diptheria, clostridium, listeria, bacillus
type III secretion
“injectisome” - pseudomonas, salmonella, shigella, e. coli
lepromatous Mycobacterium leprae
diffusely over skin - Th2 response
tuberculoid Mycobacterium leprae
limited to a few hypoesthetic, hairless skin plaques - Th1 - type immune response
leptospirosis
Leptospira interrogans - water contaminated with animal urine - surfers and in tropics - flu-like symptoms, photophobia with conjunctival suffusion
Wuchereria bancrofti
Elephantiasis - 9 mo–1 yr after bite to become symptomatic - Diethylcarbamazine
meningitis treatment
ceftriaxone, vancomycin, +/- amox if listeria
pseudomonas coverage
piperacillin, cephalosporins, flouroquinolones, carbapenems