Micro Flashcards
characteristic tumbling motility
Listeria monocytogenes
transmitted via respiratory droplets
N.meningitidis, RSV, H.influenzae, M.tuberculosis
arthropod bites
leishmaniasis (sandfly)
malaria (Anopheles mosquito)
Chagas (reduviid bug)
Lyme dz (Ixodes tick bite)
needle stick transmission
HBV, HCV, HIV
H.influenzae
small, gram neg coccobacilliary rod
epiglottis, meningitis, otitis media, pneumonia
“haEMOPhilus”
causes a palm & sole rash?
2ndary syphilis
Rocky mountain spotted fever
coxsackievirus A
Kawasaki dz
“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?
TORCHES: TOxoplasma gondii Rubella Cytomegalovirus HErpes, HIV (HSV-2 transmitted VIA DELIVERY) Syphilis
2 obligate intracellular parasites (require host ATP for energy)
Chlamydia
Ricketssiae
common causes of atypical pneumonia (class types)
Mycoplasma
Legionella
Chlamydia
Viruses
5 pediatric diseases w/ rash
Measles Rubella Scarlet fever (S.pyogenes) Roseola (HHV-6) Erythema infectiosum (parvovirus B19) - "slapped cheeks"
5 causes of common cold
rhinovirus coronavirus adenovirus influenze C virus coxsackievirus
3 common causes of conjunctivitis
H.influenzae
Adenovirus
S.pneumoniae
most common viral cause of mental retardation in US
CMV
cancers caused by EBV
Burkitt's lymphoma nasopharyngeal carcinoma (in East Asians)
HBV, HCV, HDV 4 characteristics:
Blood transmission
Chronic carrier state
Cirrhosis
HCC
smallpox eradicated bc of?
1) only ONE serotype existed
2) NO CARRIER state
3) NO ANIMAL RESERVOIRS
enveloped viruses?
susceptible to anything capable of destroying lipids (ex. bile acids)
use host cell TRANSLATION machinery
ssDNA viruses
use host cell TRANSCRIPTION machinery
dsDNA viruses
Parvovirus B19 =
ssDNA linear, nonenveloped
HPV =
nonenveloped, dsDNA circular
HPV uses what 2 factors to grow?
E6 (blocks p53), E7 (blocks Rb)
JC virus =
dsDNA circular, nonenveloped
adenoviruses =
dsDNA linear, nonenveloped
adenoviruses can cause?
resp tract infection
conjunctivitis
hemorrhagic cystitis
gastroenteritis
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?
gingivostomatitis
keratoconjunctivitis (recurrence of –> common cause of blindness in U.S)
cold sores
**temporal lobe encephalitis (focal necrosis)
HSV-1 dormant in?
trigeminal ganglion
HSV-2 dormant in?
lumbosacral ganglion
HSV-2 passed from mother to fetus can cause?
congenital defects
abortion
neonatal encephalitis
most common cause of encephalitis in U.S
HSV-1 = adults HSV-2 = neonates
“dew on a rose petal”
VZV
VZV dormant in?
DRG
CMV =
dsDNA linear, enveloped
CMV causes?
cytomegalic inclusion dz [deafness, hepatosplenomegaly, microcephaly in newborns) heterophil-NEGATIVE mononucleosis retinitis (esp in AIDS pt) pneumonia (esp in transplant pts) esophagitis
cancers ass w/ EBV?
Burkitt’s lymphoma, nasopharyngeal carcinoma (East Asians)
EBV dormant in?
B cells
bind and infect B cells via C3d complement receptor
atypical lymphocytes charact of?
EBV infection
cytotoxic T-lymphocytes react against infected B cells
HBV =
enveloped, dsDNA circular
HBV and weak immune response =
chronic state
HBV tx?
alpha-IFN or pegylated alpha-IFN
lamivudine
smallpox =
enveloped, dsDNA linear
smallpox presentation?
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
“dome-like”
features of acid-fast bacilli?
cell wall w/ mycolic acid (a lipid) –> makes wall hydroPHOBIC
after stained, retains stain!
spirochetes shape/motility?
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
M.tuberculosis =
thin RODS, non-motile obligate aerobes
linear growth
acid-fast staining bacteria?
mycobacteria, nocardia
live-attenuated vaccines for bacteria?
BCG and F.tulerensis vaccines
Mycobacterium avium complex consists of?
M.avium, M.intracellulare
major opportunistic inf in AIDS pts
M.bovis seen w/?
GI tuberculosis; unpasteurized milk
M.leprae =
same as M.tuberculosis but also grows at low temps, phenolase positive
M.leprae infect?
cells of nerve sheaths
tuberculoid leprosy =
strong immune response
granulomas formed
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
T.pallidum =
spirochete
microaerophilic
sensitive to high temps
T.pallidum contains?
endoflagellum (b/w cell wall and outer membrane)
Giemsa stain
Chlamydia Borrelia Ricketssiae Trypanosomes Plasmodium
“Certain Bugs Really Try My Patience”
PAS stain
stains GLYCOGEN, mucopolysaccharides
dx Whipple’s Dz (Tropheryma whipplei)
Ziehl-Neelson stain (carbolfuchsin)
acid-fast organisms (Nocardia, Mycobacteria)
India Ink
C.neoformans (stains CLEAR)
mucicarmine stain
C.neoformans (stains capsule RED)
Silver stain
Fungi (Pneumocystis)
Legionella
H.pylori
chocolate agar w/ factors V (_____), X (________) media for?
H.influenzae
NAD+;hematin
ENRICHMENT MEDIA
Thayer-Martin media contains?
Vancomycin (inhib Gram + org)
Polymyxin (inhib Gram - org except Neisseria)
Nystatin (inhib fungi)
SELECTIVE MEDIA!
Thayer-Martin media for?
N.gonorrheae/meningitidis
Bordet-Gengou (_______) agar for?
B.pertussis
potato!
cystine-tellurite plate
C.diphtheriae –> forms black colonies
Loffler’s media
C.diphtheriae
Lowenstein-Jensen agar for?
M.tuberculosis
pink colonies on MacConkey’s agar?
lactose-fermenting enterics!
fermentation prod acid –> turns colony pink
DIFFERENTIAL MEDIA
eosin-methylene blue agar?
E.Coli (colonies w/ green metallic sheen)
charcoal yeast extract agar buffered w/ _________ and used for?
cysteine and iron
Legionella!
Sabouraud’s agar
Fungi
“Sab’s a FUN Guy”
obligate aerobes
Nocardia
Pseudomonas aeruginosa
M.tuberculosis
Bacillus (some are facultative anaerobes)
“Nagging Pests Must Breathe”
obligate anaerobes
Clostridium
Bacteroides
Actinomyces
“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)
obligate intracellular
Rickettsiae
Chlamydia
can’t make own ATP
facultative intracellular
Salmonella Neisseria Brucella Mycobacterium Listeria Francisella Legionella Yersinia pestis
“Some Nasty Bugs May Live FacultativeLY”
catalase + organisms
Pseudomonas Listeria Aspergillus Candida E.Coli S.aureus Serratia
“you need PLACESS for your CATS”
urease + bugs
Cryptococcus H.pylori Proteus Ureaplasma Nocardia Klebsiella S.epidermidis S.saprophyticus
yellow “sulfur” granules prod by?
Actinomyces israelii
composed of filaments of bacteria
yellow pigment
S.aureus
blue-green pigment
Pseudomonas aeruginosa
red pigment
Serratia marcescens
Protein A virulence factor?
S.aureus
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)
transformation?
take up naked DNA from environement (form recomb organism)
SHiN organisms!!
what inhibits transformation from occurring?
adding deoxyribonuclease (degrades naked DNA)
what contains genes for sex pilus and conjugation?
F+ plasmid
transposition?
segment of DNA that can jump (excision, reintegration) from one location to another
can carry AB resistance or virulence factors
transduction uses?
phages!
5 bacterial toxins encoded in lysogenic phage?
shigA-like toxin Botulinum toxin Cholera toxin Diphtheria toxin Erythrogenic toxin of Strep pyogenes
“ABCDE”
beta-hemolytic bacteria
S.aureus
S.pyogenes
S.agalctiae
Listeria monocytogenes
“forms clear area”
classic drugs used to tx anaerobic infections
metronidazole
clindamycin
branching, filamentous Gram (+) rods w/ sulfur granules
Actinomyces israelii
spore forming bacteria
B.cereus
B.anthracis
Clostridrium botulinum/tetani/perfringens
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
Salmonella
traveller’s diarrhea
ETEC
staghorn calculi are what stones?
ammonium-magnesium-phosphate stones (struvite stones)
what bug causes staghorn calculi?
Proteus
hemolysis color for alpha-hemolytic
green
hemolysis color for beta-hemolytic
clear
water contaminated w/ rodent urine =
hantavirus
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
Legionella pneumophila
Chlamydophila pneumoniae
Mycoplasma pneumoniae
MRSA resistant to beta-lactams by?
altering penicillin-binding protein
S.pneumo is _______ sensitive or resistant and causes?
optochin sensitive
Meningitis
Otitis media (in children)
Pneumonia
Sinusitis
MOPS
normal flora of oropharynx and causes dental caries
S.mutans
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?
optochin resistant
S.pyogenes is __________ sensitive or resistant?
bacitracin sensitive
other S.pyogenes virulence factors
hyaluronate in capsule (antiphagocytic activity)
Streptolysin O
DNase (depolymerize viscous DNA in pus + disintegrate PML)
streptokinase (catalyze plasminogen –> plasmin)
S.agalactiae is _________ resistant or sensitive and prod what factor?
bacitracin resistant CAMP factor (enlarge area of hemolysis formed by S.aureus)
S.agalactiae positive culture requires what prophylaxis?
penicillin
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;
P.aeruginosa
Gram positive rods w/ metachromatic (blue/red) granules resembling chinese letters
spores have what in their core?
dipicolinic acid
describe Clostridria species
Gram (+), spore-formers, obligate anaerobic bacilli
oxidase (-)
C.difficile toxins
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
metronidazole
2nd = oral vanco
drugs against C.diphtheriae
erythromycin, penicillin; vaccine
B.anthracis unique feature
polypeptide capsule containing D-glutamate
3 toxins of anthrax
edema factor
lethal factor
protective antigen
wool, goat’s hair contain spores for?
Anthrax
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
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
Not acid-fast
oral/facial abscesses (usually of mandible) draining through sinus tracts [bc part of normal oral flora]
yellow “sulfur” granules
tx for actinomyces?
penicillin
Nocardia 4 defining features
Gram (+) aerobe
Acid-fast
in soil, dust, vegetation
pulmonary infections in immunocompromised; cutaneous infections after trauma in immunocompetent
Nocardia tx?
sulfonamides
congenital toxoplasmosis classic triad?
chorioretinitis
hydrocephalus
intracranial calcifications
cell types rich in smooth ER?
hepatocytes
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
Salmonella
E.Coli virulence factor for UTIs?
fimbriae
E.Coli virulence factor for pneumonia/neonatal meningitis?
K capsule
E.Coli virulence factor for shock?
LPS
organisms that use fimbriae/pili to attach to tissues/cause infection
N.meningitidis
UTI/diarrhea-causing E.coli
B.pertussis
V.cholera
common cause of Acute otitis externa
swimmer’s ear!
P.aeruginosa
S.aureus
common cause of Acute otitis media
S.pneumo
nontypable H.influenzae
M.catarrhalis
difference seen b/w bacterial and fungal/TB meningitis?
bacterial - increased PMNs!
fungal/TB - increased lymphocytes!
parvoviridae
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
S.aureus
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
shigA-like toxin Botulinum toxin Cholera toxin Diphtheria toxin Erythrogenic toxin of S.pyogenes
“ABCDE”
alpha-hemolysis produces what area
green ring around colonies
DOC for C.perfringens
metronidazole
2 - oral vanco
DOC for GBS prophylaxis
intrapartum penicillin
cutaneous anthrax
black eschar (painless ulcer) lethal factor and edema factor
pulmonary anthrax
pulm hemorrhage, mediastinitis (widened, hemorrhagic mediastinum), shock
B.cereus
diarrhea
cereulide (preformed toxin)
reheated rice
L.monocytogenes
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
Actinomyces
oral/facial abscesses draining thru sinus tracts
tx = penicillin
Nocardia
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
L.pneumophila
otitis externa distinguishing feature
granulation tissue w/in ear canal
EHEC unique from other E.Coli in that it doesn’t
ferment sorbitol
Salmonella vs Shigella
Sal: flagella dissem hematogenously prod hydrogen sulfide causes monocytic response animal reservoir (turtles)
Shigella:
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
C.jejuni
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)
leptospira
jaundice
photophobia w/ conjunctivitis
“question-mark” shaped
DOC for stage 1/2 of Lyme dz
doxycycline azithromycin (in children)
DOC for later stages of Lyme dz
ceftriaxone (for 28 days)
stage 3 lyme dz
chronic monoarthritis/migratory polyarthritis
encephalopathy/polyneuropathy
tertiary syphilis physical signs
broad-base ataxia
argyll-robertson pupil
early sign of cong syphilis
snuffles (blood tinged nasal secretions)
DOC for/cause of bacterial vaginosis
metronidazole
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
doxycycline
chlamydial cell wall unique bc it
lacks muramic acid
unique sequelae of Mycoplasma pneumo
mild anemia due to high titer of COLD agglutinins (IgM)
histoplasmosis
mississippi and ohio river valleys
w/in macrophage - smaller than RBC
blastomycosis
east of Mississippi river and central america
granulomatous nodules
broad-based budding yeast - same size as RBC
coccidioidomycosis
southwestern US, California; San Joaquin valley fever
spherules - larger than RBC
Tinea versicolor caused by
M.furfur
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 =
decreased neutrophils
superficial/localized candidiasis predisposition =
decreased T-lymphocytes
Aspergillus can produce
aflatoxins (ass w/ HCC)
conidophore w/ radiating chains of spores
C.neoformans causes what sign in brain; also, found where?
soap-bubble lesions;
found in soil, pidgeon droppings
mucor/rhizopus features
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
TMP-SMX
pentamidine, dapsone (if sulfa allergy)
DOC for sporothrix schenckii
itraconazole or K iodide
DOC for Giardia lamblia
metronidazole
tinidazole
tx for asympt E.histolytica cyst passers
iodoquinol
sympt of E.histolytica
bloody, mucous-y diarrhea
liver abscess
RUQ pain
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)
Babesiosis features
fever
hemolytic anemia
loa loa features
worm in conjunctiva
tx = diethylcarbamazine
river blindness caused by
onchocerca volvulus;
hyperpigmented skin + blindness
tx = ivermectin
Elephantiasis caused by/tx
Wuchereria bancrofti;
blocks lymphatic vessels
tx = diethylcarbamazine
Taenia solium ingested from eggs causes
cysticercosis
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
C.sinenis ass w/?
pigmented gallstones (from biliary tract inflamm) cholangiocarcinoma