Flashcards in Micro Deck (237):
characteristic tumbling motility
transmitted via respiratory droplets
N.meningitidis, RSV, H.influenzae, M.tuberculosis
malaria (Anopheles mosquito)
Chagas (reduviid bug)
Lyme dz (Ixodes tick bite)
needle stick transmission
HBV, HCV, HIV
small, gram neg coccobacilliary rod
epiglottis, meningitis, otitis media, pneumonia
causes a palm & sole rash?
Rocky mountain spotted fever
"you drive KAWASAKI CARS w/ your HANDS AND FEET"
(CA = cox A, R = RMSF, S = syphilis)
can cross placenta and allow infection from mother to fetus?
HErpes, HIV (HSV-2 transmitted VIA DELIVERY)
2 obligate intracellular parasites (require host ATP for energy)
common causes of atypical pneumonia (class types)
5 pediatric diseases w/ rash
Scarlet fever (S.pyogenes)
Erythema infectiosum (parvovirus B19) - "slapped cheeks"
5 causes of common cold
influenze C virus
3 common causes of conjunctivitis
most common viral cause of mental retardation in US
cancers caused by EBV
nasopharyngeal carcinoma (in East Asians)
HBV, HCV, HDV 4 characteristics:
Chronic carrier state
smallpox eradicated bc of?
1) only ONE serotype existed
2) NO CARRIER state
3) NO ANIMAL RESERVOIRS
susceptible to anything capable of destroying lipids (ex. bile acids)
use host cell TRANSLATION machinery
use host cell TRANSCRIPTION machinery
Parvovirus B19 =
ssDNA linear, nonenveloped
nonenveloped, dsDNA circular
HPV uses what 2 factors to grow?
E6 (blocks p53), E7 (blocks Rb)
JC virus =
dsDNA circular, nonenveloped
dsDNA linear, nonenveloped
adenoviruses can cause?
resp tract infection
adenoviruses remain latent where?
tonsillar adenoids following infection
adenoviruses contain what factor?
hemagglutinin fibers in each of 12 vertices of capsid
HSV-1, HSV-2, VZV =
enveloped, dsDNA linear
HSV, CMV, EBV envelope?
only virus that obtains envelope by budding from nuclear membrane
HSV-1 can cause?
keratoconjunctivitis (recurrence of --> common cause of blindness in U.S)
**temporal lobe encephalitis (focal necrosis)
HSV-1 dormant in?
HSV-2 dormant in?
HSV-2 passed from mother to fetus can cause?
most common cause of encephalitis in U.S
HSV-1 = adults
HSV-2 = neonates
"dew on a rose petal"
VZV dormant in?
dsDNA linear, enveloped
cytomegalic inclusion dz [deafness, hepatosplenomegaly, microcephaly in newborns)
retinitis (esp in AIDS pt)
pneumonia (esp in transplant pts)
cancers ass w/ EBV?
Burkitt's lymphoma, nasopharyngeal carcinoma (East Asians)
EBV dormant in?
bind and infect B cells via C3d complement receptor
atypical lymphocytes charact of?
cytotoxic T-lymphocytes react against infected B cells
enveloped, dsDNA circular
HBV and weak immune response =
alpha-IFN or pegylated alpha-IFN
enveloped, dsDNA linear
start as macules --> evolve to pus-filled vesicles --> crust over in 2-3 wks --> infectious particles released
molluscum contagiosum =
enveloped, dsDNA linear
unlike HSV or VZV, molluscum contagiosum is?
limited to epidermis
NO latent state
Molluscum contagiosum presentation?
flesh-colored pearly nodules/papules w/ central crater
features of acid-fast bacilli?
cell wall w/ mycolic acid (a lipid) --> makes wall hydroPHOBIC
after stained, retains stain!
corkscrew bc flexible/thin cell walls
periplasmic flagella (b/w outer membrane and cell wall) --> corkscrew motility
mycoplasma distinguishing feature?
no cell wall
chlamydia/rickettsiae species are?
obligate intracellular bacteria
mycolic acid cell wall protects from?
phagocytosis, germicides, dryness
M.tuberculosis cell wall contains?
sulfatides - inhib phagosome from fusing lysosome
thin RODS, non-motile obligate aerobes
acid-fast staining bacteria?
live-attenuated vaccines for bacteria?
BCG and F.tulerensis vaccines
Mycobacterium avium complex consists of?
major opportunistic inf in AIDS pts
M.bovis seen w/?
GI tuberculosis; unpasteurized milk
same as M.tuberculosis but also grows at low temps, phenolase positive
cells of nerve sheaths
tuberculoid leprosy =
strong immune response
thickened palpable nerves and 1-2 anesthethized lesions that are hypopigmented and hairless
lepromatous leprosy =
weak immune response
inflamm damage --> sensory loss at face, extremities
loss of eyebrows, saddle-nose deformity (thick nose), leonine facies (thick cheeks), infertility
tx of leprosy SE?
type 1 = DTH response --> intensified tuberculoid-like sympt; tx w/ prednisone
type 2 = immune-complex dep --> erythema nodosum leprosum; tx w/ thalidomide
sensitive to high temps
endoflagellum (b/w cell wall and outer membrane)
"Certain Bugs Really Try My Patience"
stains GLYCOGEN, mucopolysaccharides
dx Whipple's Dz (Tropheryma whipplei)
Ziehl-Neelson stain (carbolfuchsin)
acid-fast organisms (Nocardia, Mycobacteria)
C.neoformans (stains CLEAR)
C.neoformans (stains capsule RED)
chocolate agar w/ factors V (_____), X (________) media for?
Thayer-Martin media contains?
Vancomycin (inhib Gram + org)
Polymyxin (inhib Gram - org except Neisseria)
Nystatin (inhib fungi)
Thayer-Martin media for?
Bordet-Gengou (_______) agar for?
C.diphtheriae --> forms black colonies
Lowenstein-Jensen agar for?
pink colonies on MacConkey's agar?
fermentation prod acid --> turns colony pink
eosin-methylene blue agar?
E.Coli (colonies w/ green metallic sheen)
charcoal yeast extract agar buffered w/ _________ and used for?
cysteine and iron
"Sab's a FUN Guy"
Bacillus (some are facultative anaerobes)
"Nagging Pests Must Breathe"
"anaerobes Can't Breathe Air"
foul smelling, difficult to culture, produce gas in tissue
what drug class is ineffective against anaerobes?
Aminoglycosides (req O2 to enter)
can't make own ATP
"Some Nasty Bugs May Live FacultativeLY"
catalase + organisms
"you need PLACESS for your CATS"
urease + bugs
yellow "sulfur" granules prod by?
composed of filaments of bacteria
Protein A virulence factor?
binds Fc region of Ig --> prevents opsonization/phagocytosis
IgA protease virulence factor?
S.pneumo, H.flu B, Neisseria ("SHiN")
cleaves IgA --> colonize respiratory mucosa
M protein virulence factor?
group A strep
prevent phagocytosis and activation of complement!
features of exotoxin
genes located for in plasmid or bacteriophage;
made of polypeptide;
induces high-titer Ab (antitoxins)
ONLY staph enterotoxin not destroyed at 60 degrees C
features of endotoxin
located in outer cell membrane of Gram -;
made of LPS;
causes fever, shock by release of TNF, IL-1
superantigen cause what?
overwhelming release of IFN-gamma and IL-2
3 effects of endotoxin
activates macrophages (TNF, IL-1, NO)
activates complement (C3a, C5a)
activates tissue factor (coag cascade --> DIC)
take up naked DNA from environement (form recomb organism)
what inhibits transformation from occurring?
adding deoxyribonuclease (degrades naked DNA)
what contains genes for sex pilus and conjugation?
segment of DNA that can jump (excision, reintegration) from one location to another
can carry AB resistance or virulence factors
5 bacterial toxins encoded in lysogenic phage?
Erythrogenic toxin of Strep pyogenes
"forms clear area"
classic drugs used to tx anaerobic infections
branching, filamentous Gram (+) rods w/ sulfur granules
spore forming bacteria
see "picnics" and egg salad or chicken salad, think?
S.aureus - immed (1-6 hrs) vomiting/diarrhea
Salmonella - occurs 1-3 days later
transmission from turtle
staghorn calculi are what stones?
ammonium-magnesium-phosphate stones (struvite stones)
what bug causes staghorn calculi?
hemolysis color for alpha-hemolytic
hemolysis color for beta-hemolytic
water contaminated w/ rodent urine =
Borrelia burgdorferi transmitted by, and, natural reservoir =
transmit by Ixodes tick (also holds Babesia)
reservoir = mouse
BILATERAL Bell's palsy ass w/?
stage 2 Lyme dz
stage 2 Lyme dz manifestations?
bilateral bell's palsy (w involved forehead);
AV nodal block
3 biggies in atypical (interstital) pneumonia
MRSA resistant to beta-lactams by?
altering penicillin-binding protein
S.pneumo is _______ sensitive or resistant and causes?
Otitis media (in children)
normal flora of oropharynx and causes dental caries
causes subacute bacterial endocarditis at damaged valves, and by doing what?
S.sanguis - sticks to damaged valves by making glycocalyx
most commonly precedes acute PSGN
impetigo > pharyngitis
S.viridans are ________ resistant or sensitive?
S.pyogenes is __________ sensitive or resistant?
other S.pyogenes virulence factors
hyaluronate in capsule (antiphagocytic activity)
DNase (depolymerize viscous DNA in pus + disintegrate PML)
streptokinase (catalyze plasminogen --> plasmin)
S.agalactiae is _________ resistant or sensitive and prod what factor?
CAMP factor (enlarge area of hemolysis formed by S.aureus)
S.agalactiae positive culture requires what prophylaxis?
Enterococci (Group D strep) are resistant to what drug and grow in what?
resistant to penicillin G
grow in 6.5% NaCl and bile
S.bovis causes what?
subacute endocarditis in COLON CANCER PTS
C.diphtheriae acquires virulence via? has a toxin similar to? appearance in microscope?
bacteriophage-mediated infection w/ Tox gene --> codes for AB exotoxin;
Gram positive rods w/ metachromatic (blue/red) granules resembling chinese letters
spores have what in their core?
describe Clostridria species
Gram (+), spore-formers, obligate anaerobic bacilli
Toxin A --> enterotoxin (binds to brush border of gut --> intestinal fluid secretion and inflamm)
Toxin B --> cytotoxin (destroys cytoskeletal structure of enterocytes = kills enterocytes)
DOC for C.difficile
2nd = oral vanco
drugs against C.diphtheriae
erythromycin, penicillin; vaccine
B.anthracis unique feature
polypeptide capsule containing D-glutamate
3 toxins of anthrax
wool, goat's hair contain spores for?
widened mediastinum and pulm hemorrhage seen in?
Woolsorter's dz (B.anthracis)
reheated rice synd + cause/toxin
B.cereus --> cereulide (preformed toxin)
able to multiply at 4 degrees C
L.monocytogenes is a ? and tx = ?
facultative intracellular microbe (taken up by monocytes) acquired by ingestion of unpasteurized milk/cheese and deli meats + passed on during vaginal birth
tx = ampicillin in infants/elderly/immunocomp
Actinomyces 4 defining features
Gram (+) anaerobe
oral/facial abscesses (usually of mandible) draining through sinus tracts [bc part of normal oral flora]
yellow "sulfur" granules
tx for actinomyces?
Nocardia 4 defining features
Gram (+) aerobe
in soil, dust, vegetation
pulmonary infections in immunocompromised; cutaneous infections after trauma in immunocompetent
congenital toxoplasmosis classic triad?
cell types rich in smooth ER?
steroid hormone-producing cells of adrenal cortex
formation of spiral septum?
truncoconical swellings fuse + turn 180 degrees
neural crest cell derivative!
underlying cause of transposition of great vessels
180 degree spin didn't take place
underlying cause of persistent truncus arteriosus
failure of neural crest cell migration
congenital defects with present shunts
persistent truncus arteriosus - VSD
tricuspid atresia - REQ BOTH ASD + VSD
TAPVR - ASD + sometimes PDA
ToF - VSD
transposition of great vessels - REQ ASD, VSD, OR PFO
2 common causes of osteomyelitis in otherwise healthy children
#1 = S.aureus
#2 = S.pyogenes
osteomyelitis in sickle cell dz
E.Coli virulence factor for UTIs?
E.Coli virulence factor for pneumonia/neonatal meningitis?
E.Coli virulence factor for shock?
organisms that use fimbriae/pili to attach to tissues/cause infection
common cause of Acute otitis externa
common cause of Acute otitis media
difference seen b/w bacterial and fungal/TB meningitis?
bacterial - increased PMNs!
fungal/TB - increased lymphocytes!
non enveloped, ssDNA
what do Cowdry type A bodies look like?
intranuclear eosinophilic droplets (seen in HSV, CMV)
conjugated vaccines are what?
polysaccharide antigen + protein
exotoxin not destroyed at 60 degrees C is made by
conjugation w/ F+ plasmid will
NOT transfer chromosomal genes
conjugation w/ high-freq recombination cell (Hfr) will
transfer plasmid AND chromosomal genes
toxins w/ genes encoded in a lysogenic phage
Erythrogenic toxin of S.pyogenes
alpha-hemolysis produces what area
green ring around colonies
DOC for C.perfringens
2 - oral vanco
DOC for GBS prophylaxis
black eschar (painless ulcer)
lethal factor and edema factor
pulm hemorrhage, mediastinitis (widened, hemorrhagic mediastinum), shock
cereulide (preformed toxin)
tumbling motility (actin)
able to multiply @4 degrees C (cold)
ampicillin for empirical meningitis tx
listeriolysin - activated in acidified phagosomes in monocytes; can lyse vacuolar membrane
oral/facial abscesses draining thru sinus tracts
tx = penicillin
pulm infections in immunosupp
cutaneous infections after trauma in immunocompetant
tx = sulfonamides
Mycobacterium 2 factors in virulent strains
cord factor - inhib macrophage maturation + induce release of TNF-alpha; "serpentine" looking
sulfatides (surface glycoproteins) - inhib phagolysosomal fusion
tx for leprosy
tuberculoid - dapsone + rifampin 6 mo.
lepromatous - dapsone, rifampin, clofazimine 2-5 yrs
Gram neg bacteria resistant to?
penicillin G and vancomycin
N.gonorrheaoe vs. N.meningitidis
N.Meng - has polysacch capsule; nasopharyngeal colonization (resp/oral transmission)
HiB vaccine unique in that
it contains pentose monosacch (polyribosylribitol phosphate) conjugated to diphtheria toxoid or other protein
which bug shows up w/ hyponatremia on labs
otitis externa distinguishing feature
granulation tissue w/in ear canal
EHEC unique from other E.Coli in that it doesn't
Salmonella vs Shigella
prod hydrogen sulfide
causes monocytic response
animal reservoir (turtles)
cell-to-cell trans (P2P, contaminated food/water)
AB shorten duration of fecal excretion
causes PMN response
can be transmitted from domestic animals to humans
V.cholerae can benefit from what state
achlorhydia (from PPI use, ex)
triple therapy for H.pylori
PPI, clarithromycin, amoxicillin/metronidazole
H.pylori mainly colonizes where
gastric antrum (duodenal bulb)
spirochetes disting factor
axial filaments (flagella located in diff location than others)
photophobia w/ conjunctivitis
DOC for stage 1/2 of Lyme dz
azithromycin (in children)
DOC for later stages of Lyme dz
ceftriaxone (for 28 days)
stage 3 lyme dz
chronic monoarthritis/migratory polyarthritis
tertiary syphilis physical signs
early sign of cong syphilis
snuffles (blood tinged nasal secretions)
DOC for/cause of bacterial vaginosis
from overgrowth of certain bacteria in vagina
R.typhi, R.prowazekii cause
typhus; rash starts centrally + spreads out, sparing palms/soles
sign of Ehrlichiosis
granulocytes w/ berry-like inclusions in cytoplasm
DOC for LGV
chlamydial cell wall unique bc it
lacks muramic acid
unique sequelae of Mycoplasma pneumo
mild anemia due to high titer of COLD agglutinins (IgM)
mississippi and ohio river valleys
w/in macrophage - smaller than RBC
east of Mississippi river and central america
broad-based budding yeast - same size as RBC
southwestern US, California; San Joaquin valley fever
spherules - larger than RBC
Tinea versicolor caused by
degrad of lipids --> prod acids --> damage melanocytes --> hypo/hyperpigmented patches (not pruritic)
other tinea lesions usually show what histo
pruritic lesions w/ central clearing resembling ring
tx for vaginal/localized candidiasis
nystatin (topical med)
disseminated candidiasis predisposition =
superficial/localized candidiasis predisposition =
Aspergillus can produce
aflatoxins (ass w/ HCC)
conidophore w/ radiating chains of spores
C.neoformans causes what sign in brain; also, found where?
found in soil, pidgeon droppings
HA, facial pain (periorbital pain)
black necrotic eschar on face (palate or nose usually)
have ketone reductase (therefore prolif in excess glucose/ketone)
DOC for PCP
pentamidine, dapsone (if sulfa allergy)
DOC for sporothrix schenckii
itraconazole or K iodide
DOC for Giardia lamblia
tx for asympt E.histolytica cyst passers
sympt of E.histolytica
bloody, mucous-y diarrhea
flask-shaped ulcer if colon ruptures
tx for Toxoplasmosis
sulfadiazine + pyrimethamine
features/tx for Trypanosoma brucei gambiense/rhodesiense
LAD, RECURRING FEVER (due to antigenic variation), coma (late)
suramin (if blood-borne dz)
melarsoprol (for CNS penetration)
loa loa features
worm in conjunctiva
tx = diethylcarbamazine
river blindness caused by
hyperpigmented skin + blindness
tx = ivermectin
Elephantiasis caused by/tx
blocks lymphatic vessels
tx = diethylcarbamazine
Taenia solium ingested from eggs causes
neurocysticercosis ("swiss-cheese" appearance in brain) - tx w/ -bendazoles + dexamethasone
diphyllobothrum latum causes
vit B12 def
before removing E.granulosus cysts what do you do?
preinject w/ ethanol to kill cysts
S.hematobium ass w/?
SCC of bladder