Micro Flashcards
Causes of non-gonococcal urethritis
Chlamydia and ureaplasma. These lack peptidoglycan within their cell wall.
how do u treat NGU
azithromycin
how do u treat gonococcal urethritis
ceftriaxone
Diarrhea with PAS-positive granules and foamy macrophages
tropheryma whippelii
–will also have greasy stools and joint pain
LPS induces:
TNF and IL-1
antigen in LPS
O polysaccharide
capsules are made of polysaccharide except in
bacillus anthrax–glutamate
glycocalyx
mediates adhesion to foreign surfaces
dipicolinic acid
like keratin and peptidoglycan, can form outside of spore
listeria morphology
gram positive rod
gardnerella morphology
gram variable rod (but technically gram positive, no outer membrane
legionella morphology
gram negative rod
yerseinia morphology
gram negative rod
legionella morphology
gram negative rod
bordetella morphology
gram negative rods
all the “-ellas” except garnerella morphology
gram negative rods
branching filamentous gram positive bacteria
actinomyces, nocardia
pleomorphic gram negative
rickettsia
chlamydia
spiral gram negative
leptospira
borrelia
treponema
mycoplasma cell membrane contains
sterols
mycobacteria cell wall contains
mycolic acid and high lipid content
silver stain
legionella
H pylori
fungi
giemsa stain
chlamydia borrelia rickettsiae trypanosomes plasmodium
ziehl neelsen stain
nocardia, mycobacterium
PAS stains for
glycogen
thayer martin media
neisseria. contains vanco, polymyxin, and nystatin
bordet gengou agar for
bordetella
tellurit, loffler’s media for
diptheria
lowenstein jensen agar
TB
eaton’s agar
mycoplasma pneumonia
charcoat yeast extract buffered with cystein and iron
legionella
sabouraud’s agar
fungi
obligate aerobes
nocardia
pseudomonas
mycobacterium TB
bacillus
obligate anaerobes
clostridium
bacterioides
actinomyces
obligate intracellular
rickettsia, chlamydia
facultative intracellular
salmonella neisseria mycobacterium
brucella, legionella, francisella, listeria, yersinia pestis
quellung rxn
if encapsulated bug is present, capsule swells
encapsulated bacteria
strep pneumo haemophilus neisseria e coli salmonella klebsiella group B strep
catalase positive
pseudomonas listeria aspergillus candida e coli, s aureus, serratia
conjugated vaccines
meningococcal
HiB
Prevnar is conjugated, Pneumovax is not
urease positive bugs
cryptococcus H pylori Proteus Ureaplasma Nocardia Klebsiella S epidermidis S saprophyticus
red pigment bacteria
serratia marcescens
protein A
binds Fc region of Ig
S aureus
prevents opsonization and phagocytosis
M protein
prevents phagocytosis
exotoxin vs endotoxin in heat
exotoxin destroyed rapidly at 60C (except staphy HS toxin)
Endotoxin stable at 100 degerees for 1 hr
exotoxin are made of
proteins.
diptheria toxin causes
pharyngitis with pseudomembranes and severe lymphadenopathy
pseudomonas aeruginosa releases
exotoxin A kills host cells
mechanism of diptheria/pseudomonas toxin
inactivates EF2
shiga toxin causes
GI mucosal damage and dysentery. HUS
EHEC releases
Shiga like toxin. Causes HUS.
Difference btw shigella and EHEC?
EHEC does NOT invade host cells
mechanism shigella toxin
inactivates 60S ribosome
ETEC heat labile toxin
activates adenylate cyclase to increase chloride secretion in gut “labile in the air”
ETEC heat stable toxin
activates cGMP to decrease Cl absorbtion in gut “stable on th eground”
bacillus anthrax releases
edema factor: mimics cAMP
vibrio cholera mechanism
overactivates adenylate cyclase by activating Gs
pertussis toxin mechanism
disables Gi to impair phagocytosis
tetanus toxin blocks
inhibitory neurotransmitters GABA and glycine
perfringens toxin
alpha toxin: degrades phospholipid C
double zone of hemolysis
perfringens
strep pyogenes (GAS) tox
streptolysin O: degrades cell membrane
ASO titer
strep pyogenes against toxin
S aureus toxin
toxic shock syndrome toxin
Mechanism TSST-1
bring MHC II and TCR in close proximity causing overwhelming release of IFN-y and IL-2
Mechanism exotoxin A of strep pyogenes
bring MHC II and TCR in close proximity causing overwhelming release of IFN-y and IL-2
what does streptolysin O do?
lyses RBCs
Strep pyogenes
releases exotoxin A
LPS activates
IL-1 TNF Nitric Oxide C3a C5a DIC
Which bacteria can transform?
SHiN species
F+x F- conjugation transfers
Only plasmids
Hfr x F transfers
F plasmid incorporated into DNA. Can transfer both plasmid and chromosomeal genes
generalized transduction
phage picks up parts of bacterial DNA
specialized transduction
occurs during lysogenic phase. Viral DNA is incorporated into bacterial chromosome and when excised, takes flanking DNA with it.
Which fiver toxins are found in the lysogenic phage?
ShigA like botulinum cholera diptheria erythrogenic
gram positive, branching anaerobe
actinomyces
gram positive, aerobe, acid fast
nocardia
gram positive rods
clostidrium listeria bacillus mycobacterium corynebac
gm + cocci, catalase positive, coagulase -
novobiocin sensitive
S. epidermidis
gm + cocci, catalase positive, coagulase -
novobiocin resistant
S saprophyticus
gm + cocci, catalase neg,
partial hemolysis
optichin sensitive?
optochin resistant?
Optochin sen: S pneumo
optochin res: viridans strep
catalase - gram positive cocci
beta hemolysis
-Bacitracin sensitive? resistant?
sensitive: GAS
resistant: GBS
catalase - gram positive cocci
no hemolysis
-growth in bile and 6.5 NaCL?
growth only in bile?
bile and salt: Enterococcus
Growth in only bile: S bovis
TSS what happens at cell level
activation of macrophages and T lymphocytes in a polyclonal fashion
strep pneumo loses virulence if
It has no capsule
lancet shaped, gram positive diplococci
strep pneumo
–secretes igA protease
sepsis in sickle cell anemia and splenectomy
strep pneumo
rusty sputum
strep pneumo
strep sanguis
sticks to damaged valves of heart by making glycocalyx
scarlet fever: sx? cause?
GAS
scarlet rash sparing face, strawberry tongue, scarlet throat
two types of GAS
pyogenic: pharyngitis, cellulitis, impetico
toxigenic: scarlet fever, toxic shock, necrotizing fas.
Group B strep causes
pneumonia, meningitis, sepsis in babies
Group B strep produces
CAMP factor. This enlargeds ares of hemolysis formed by S aureus. Streak these two bugs in a cross and will find an “arrow” of fresh hemolysis
hippurate test positive
Group B strep
Tx for pregnant women with group B strep
penicillin INTRA partum
enterococci cause
UTI
biliary infection
subacute endocarditis
lancefield grouping of strep based on
differences in C carbohydrate
Group D strep causes
subacute endocarditis in colon cancer
diptheria toxtin works by
ADP ribosylates EF-2
pseudomembranous pharyngitis, a gray white membrane
diptheria
other sx of diptheria
myocarditis and arrhythmias
gram positive rods with blue and red metachromatic granules
c. diptheria
elek’s test for toxin positive
diptheria
diptheria toxin encoded by
beta-prophage
how do you kill spores
autoclave: steam at 121 for 15 minutes
other spore formers (less obvious)
B cereus
Coxiella burnetii
you suspect a can of food is infected with C. botulinum. However, it’s really tasty and you don’t want to throw it away. what do you do?
heat it up! Should inactivate the toxin
How does C perfringens toxin work?
The alpha toxin is a lecithinase, which breaks down phospholipase
C difficile toxins
Toxin A: binds brush border of gut
Toxin B: destroys the cytoskeleton of enterocytes causing pseudomembranous colitis
Dx: c difficile
detect toxins in the stool
you meet a wool sorter with flu like sx
pulmonary anthrax. worry about pulmonary hemorrhage, mediastinitis, and shock
cause of sx in reheated rice disease
B cereus: makes cereulide, a toxin causing emesis within 1-5 hours. If diarrhea, watery nonbloody diarrhea in 8-18 hrs
actin rockets which shoot around, causing tumbling motiliy
listeria monocytogenes.
how do you get listeria
milk/cheese
or vaginal transmission during birth
treat actinomyces
penicillin
treat nocardia
sulfonamides
branching bacteria causing oral/facial abscess draining through sinus tracts
actinomyces
branching bacteria causing pulmonary infections in immunocompromised and cutaneous infections after trauma
nocardia
what tells you if TB is virulent?
cord factor: inhibits macrophage maturation and induces release of TNF-a
sulfatides in TB
inhibit phagolysosomal fusion
prophylaxis for MAC
azithromycin
m leprae infects
The skin and superficial nerves: causes loss of sensation. Cannot be grown in vitro
lepromatous leprosy
diffuse, communicable, mostly Th2 response
Tuberculoid leprosy:
Only a few plaques. Th1 response
Tx: leproxy
dapsone and rifampin for 6 months if tuberculoid
If lepromatous form, add clofazimin and treat for 2-5 years
gram negative oxidase positive, comma shaped, and grows in 42 C
campylobacter
gram negative oxidase positive, comma shaped, and grows in alkaline media
vibrio cholera
gram negative rod, fast lactose fermenter
kelbsiella and E coli
gram negative rod, slow fermenter
citrobacter, serratia, and family
gram negative, not lac fermenter, oxidase negative
shigella salmonella proteus
gram negative, not lac fermenter, oxidase positive
pseudomonas
H pylori
gram negative diplococci maltose fermenter
N meningitis
gram negative diplococci maltose nonfermenter
N gonorrhea
gram negative pleomorphic rods
HiB
Bordetella
pasteurella
brucella
why is there no vaccine for gonorrhea?
rapid antigenic variation of pilus proteins
which neisseria is encapsulated?
meningococci
long term complication of gonorrhea
fitz-hugh-curtis syndrome
long term complication of meningococci
waterhouse friderichsen
tx for gonorrhea
ceftriaxone PLUS azithromycin/coxy for chlamydia coinfection
tx for meningitis (in general)
ceftriaxone/penicillin G
prophylaxis of meningitis (In general)
rifampin, cipro, ceftriaxone
cherry red epiglottis
haemophilus
what are factors V and X on chocolate agar?
V: NAD+
X: hematin
what can be used instead of factors V and X?
Cogrow with staph aureus which provides factor V
dx: legionella
antigen in urine
how do you get legionella?
environmental source. NO person to person transmission!
Tx: legionella
macrolide or quinolone
sx of legionnaire
severe pneumonia, fever, Gi, and CNS sx
diabetic osteomyelitis
pseudomonas
malignant otitis externa in diabetic
pseudomonas
Produces a blue green pigment, and has a grape like odor
pseudomonas
Tx: pseudomonas
aminoglycosides plus piperacillin/ticarcilin
Two toxins released by pseudomonas
endotoxin: fever/shock
exotoxin A: inactivates EF-2
virulence factor for E coli UTI
P pili/fimbrae
virulence factor for E coli neonatal meningitis/pneumonia
K1 capsule
EIEC pathogenicity
invasion of intestinal mucosa: necrosis/inflammation. No toxins
E coli with dysentery
EIEC
E coli in children causing diarrhea
EPEC
E coli causing dysentery but does not ferment sorbitol
EHEC
ETEC pathogenicity
Labile and heat stable toxin produce diarrhea. no inflammation
EPEC pathogenicity:
No toxin. just adheres and sits on surface, preventing absorption.
EHEC pathogenicity:
Shiga like toxin=HUS (anemia, thrombocytopenia, and acute renal failure)
Also invasive causing endothelium swelling and mechanical hemolysis
E coli causing: Stacked brick intestinal lesions
EAEC
E coli from ground beef
EHEC
susceptible to kleb
alcoholics
diabetics
mucoid colonies with abundant polysaccharide
klebsiella
most common cause of osteomyelitis in SCD
salmonella
Shig vs Salm: disseminates hematogenously
salmonella
Shig vs Salm: antibiotics prolong symptoms
salmonella
Shig vs Salm: antibiotics prolong excretion of org in feces
shigella
Shig vs Salm: causes a monocytic response
salmonella
Shig vs Salm: causes a PMN infiltration
Shigella
Shig vs Salm: produces hydrogen sulfide
salmonella
fecal leukocyte test in vibrio cholera
NEGATIVE: no invasion
How do you get campylobacter
fecal oral
how do you get yersinia enterocolitica?
pet feces (puppies), contaminated milk or pork
how does yersinia enterocolitis present?
Looks like crohns or appendicitis. But actually a “mesenteric adenitis”
Which bugs activate cGMP?
ETEC, yersinia
Which bugs activate cAMP?
pertussis ETEC vibrio cholera campylobacter bacillus cereus bacillus anthrax
Tx: H pylori
triple therapy: clarithromycin, amoxacillin, metronidazole
Spirochetes
Borrelia
Leptospira
Tremponema
BLT, Bacon is BIG (size)
spirochete visualized with aniline dyes (wright or giemsa)
borrelia
surfers in hawaii getting flu like symptoms and jaundice with photophobia
leptospira interrogans. Get this from water contaminated with animal urine
weil’s disease
severe form of leptospira causing jaundize and azotemia from liver and kidney dysfunction with hemorrhage and anemia
Tx for lyme
doxycycline, ceftriaxone
natural reservoir of lyme
MOUSE (although transmited by ixodes)
Stage 2 of lyme
cardiac block and facial nerve palsy
stage 3 of lyme
arthritis
encephalopathy
polyneuropathy
Dx: syphilis
Screen with VDRL
Confirm with FTA-ABS
–Can visualize by scraping chancre or conylomata lata
2ndary syphilis
palms and soles rash
condylomata lata
tertiary syphilis
gummas
aortitis (may have stroke)
tabes dorsalis (positive romberg)
argyll robertson (accommodate but don’t react)
baby with saber shins, saddle nose, and deafness, with hutchinson’s teeth (gaped, peg shaped) and mulberry molars
congenital syphilis
causes of false positive VDRL
reacts with beef cardiolipin.
- -viral infection (hepatitis, mono)
- -drugs
- -SLE, rheumatic fever
- -leprosy
flu like syndrome immediatedly after antibiotics are started
Jarisch Herxheimer rxn
borrelia recurrentis transmission
louse. recurs b/c of variable surface antigen
brucella transmission
unpasteurized dairy
campylobacter transmission
PUPPIES and livestock
coxiella transmission
aerosols of cattle amniotic fluid
ehrlichiosis
lone star tick
francisella tularemia
ticks, rabbits, deer fly
which form of leprosy is transmissible?
lepromatous
bacillary angiomatosis
BAD catscratch in pts with HIV
rickettsia prowazekii transmission
louse
rickettsia rickettsii transmission
dermacentor tick bite
rickettsia typhi transmission
fleas
yersinia transmission
fleas.
yersinia reservoir
rats and prairie dogs
pleomorphic gram variable rod causing gray vaginal discharge with a fishy smell
gardnerella vaginalis
CLUE cells (vaginal epithelial cells covered with bacteria)
gardnerella vaginalis
Tx: gardnerella
metro
Tx for all rickettsial dz
doxy!
rash starting at wrists and ankles spreading to trunks, palms, and soles
rickettsia rickettsii, RMS
what cofactors is rickettsia missing that make it obligate intracellular?
CoA and NAD+
endemic typhus
R typhi
epidemic typhus
R prowazekii
Rash starts in the trunk
Epidemic typhus. R prowazekii
Which diseases cause a palm and sole rash?
COX A
RMS fever
secondary syphillis
monocytes with morula (berry like inclusions) in cytoplasm
ehrlichiosis
granulocytes with morula in cytoplasm
anaplasmosis
pneumonia in a vet or person who takes care of livestock. No rash.
Q fever.
What’s special about Q fever
It has an endospore form
chlamydia elementary body
infectious, enters cells through endocytosis
chlamydia reticulate body
replicates in cell by fission
Chlamydia pneumonia and psittaci cause
atypical pneumonia
Tx for chlamydia
azithromycin (one time use) doxy works too but longer treatment
Dx chlamydia
cytoplasmic inclusions on giemsa or fluorescent antibody smear
special about chlamydia cell wall
No muramic acid
which chlamydia serotypes cause blindness and conjucntivitis in africa?
A,B,C
Which chlamydia serotypes cause urethritis/PID?
D-K
chlamydia L1-L3?
lymphogranuloma venereum
neonate with staccato cough
think neonatal chlamydial pnemonia
Pneumonia where X ray looks worse than pt
mycoplasma pneumonia
pneumonia with a high titer of agglutinins
mycoplasma pneumonia
Tx mycoplasma pneumonia
macrolide or fluoroquinolone
typical demographic for mycoplasma pneumonia
miliary recruits/prisons
From bird or bat droppings in mississippi/ohio river valleys. Pneumonia, cough, fever. self limited
histoplasmosis.
East of mississippi river and central america. Granulomatous nodules. inflammatory lung disease disseminating to skin and bone
blastomycoses
Histology of blasto
broad based buds (look like fisheyes) same size as RBC
Histology of histo
macrophage FILLED with small hisoplasma like a bag of jelly beans smaller than RBC
Southwest. pneumonia and meningitis that can disseminate to bone and skin.
coccidioides
Histology coccidioides
endospore filled with spherules (looks like a hat/helmet) much larger than RBC
budding yeast with captain’s wheel formation in traveller to latin america
paracoccidioides
All fungi we need to know are dimorphic and yeast form at body temperature except
coccidioidomycosis, a spherule in tissue
Treatment for mycoses
Local: fluconazole or itraconazole
Systemic: Ampho B
tinea versicolor pathophysiology
degradation of lipids makes acid which damage melanocytes
tx: tinea versicolor
topical miconazole or selenium sulfide
spaghetti and meatballs on KOH
tinea versicolor
which mycoses ONLY have hyphae (mold form)
rhizopus and aspergillus
Tx: candida
azole if vaginal
fluconazole/caspo if oral
ampho B/caspofungin if systemic
who gets allergic bronchopulmonary aspergillosis?
Asthma
CF pts.
Treat with steroids
Who else is susceptible to aspergillus?
Pts with TB. aspergillus can colonize the lung cavities
where do you find cryptococcus?
soil or pidgeon dropping
culture crypto on
sabouraud’s agar
dx: crypto
latex agglutination test.
soap bubble lesions in brain, on histology but no change on CT
crypto
tx: crypto
ampho B and flucytosine
mucro and rhizopus
cause frontal lobe abscess with headache. May have black necrotic eschar on face or cranial nerve involvement
disc shaped yeast on methenamine silver stain of lung tissue
PCP
Tx for PCP
TMP-SMX
prophylaxis for PCP?
CD4 <200
dimorphic cigar shaped budding yeast
sporothrix xhenckii
rose gardener’s disease with ulcer and draining lymphatics.
sporotrichosis
Tx: sporotrichosis
itraconazole or POTASSIUM iodide
transmission giardia
cysts in water
dz giardia
trophozoites or cysts in stool
what does giardia look like trophozoite form?
A scary kite
bloody diarrhea with liver abscess and anchovy paste exudate
amoeba
histology of amoeba
flask shaped ulcer
dx stage amoeba
trophozoites in cytoplasm or cyst in the stool (with multiple nuclei)
Tx: amoeba
metro
Tx: asymptomatic amoeba
idoquinol
cryptosporidium sx
severe diarrhe ain AIDS, mild diarrhea otherwise
Dx: cryptosporidium
cysts on acid fast stain
Tx; cryptosporidium
nitazoxanide if immunocompetent
classic triad of toxo
chorioretinitis
hydrocephalus
intracranial calcifications
– can be mono like illness if u r healthy
when is toxo transmitted?
across the placenta
Dx of toxo
serology or biopsy
Tx for toxo
sulfadiazine + pyrimethamine
person swam in a freshwater lake and got rapidly fatal meningoencephalitis
naegleria
tx: naegleria
not much! occasionally ampho but most people die
dx: naegleria
amoebas in spinal fluid
african sleeping sickness (enlarged lymph nodes, bouts of fever, coma, somnolence) caused by:
trypanosomes
transmission trypanosomes
tsetse fly, painful bite
Dx: trypanosomes
blood smear
tx: trypanosomes
suramin for blood borne disease
melarsoprol for DNS penetration
malaria with 48 hr cycle and dormant form in liver
P vivax
malaria with severe, irregular fevers and banana shaped diagnostic form
falciprum
malaria with a 72 hour cycle
P malariae
First line tx for plasmodium
chloroquine, blocks plasmodium heme polymerase. If resistant, use mefloquine
Tx: life threatening plasmodium
intravenous quinidine (test for G6PD deficiency first)
Tx: dormant hypnozoite plasmodium vivax
primaquine
Sx: babesia
fever and hemolytic anemia
Dx: babesia
maltese cross on blood smear along with ring form.
PCR
Who is at increased risk of babesia?
asplenic
tx: babesia
atovaquone + azithromycin
pathogen in chagas
trypanosoma cruzi
sx: chagas
cardiomyopathy
megacolon
megesophagus
tx: chagas
nifurtimox
Sx: Leishmaniasis
spiking fevers, hepatosplenomegaly, pancytopenia
Transmission: leishmaniasis
sand fly
Dx: leishmaniasis
macrophages with amastigotes
Tx: leishmaniasis
sodium stibogluconate
foul green discharge with itching and burning
trichomonas vaginalis
transmission trichomonas (vs gardenella)
trichomonas=STD
gardenella= NOT an STD!
Tx and Dx for trichomonas
trophozoites on wet mount
–metronidazole
Tx for pinworm
mebendazole/pyrantel pamoate
Tx for ascaris
bendazoles
how do you get ascaris?
fecal oral. worry about intestinal obstruction
tx stronyloides
ivermectin/albendazole
tx for ancylostoma duodenale, necator americanus (hookworm)
bendazole
transmission: strongyloides
soil penetrate skin
Sx strongyloides
vomiting, diarrhea, anemia
Sx hookworms
anemia
Dracunulus medinensis
skin inflammation and ulceration from a nematode. get it from drinking water
Tx: dracunculus
slow extraction of worm
Onchocerca volvulus
nematode causing hyperpigmented skin and river blindness (black flies, black skin, black sight)
Tx of onchocerca
ivermectin
trans: onchocerca
female black fly
loa loa
nematode causing skin swelling and worm in conjunctiva
Tx: loa loa
diethylcarbamazine
trans: loa loa
deer fly, horse fly, mango fly
wuchereria bancrofti
nematode that causes elephantiasis. sx after 1 year
Wucheria tx
diethylcarbamazine
toxocara canis transmission
food contaminated with eggs
toxocara canis sx
nematode causing visceral larva migrans
tx toxocara
albendazole or mebendazole
ingesting larvae in undercooked pork
taenia solium
sx: taenia solium
cysticercosis . seizures or brain cysts
tx taenia solium
praziquantel
diphyllobothrium latum transmission
larvae from raw freshwater fish
sx: diphyllobothrium
B12 deficiency=anemia
tx: diphyllo
praziqunatel
echinococcus transmission
ingestion of eggs from dog feces
sx: echinococcus
cysts in liver. causing anaphylaxis if antigens are released.
how to prevent echinococcus anaphylaxis?
pre-inject cyst with ethanol
Tx echinococcus
bendazoles
schistosoma host
snail
schistosoma infectious state
cercariae. a fluke.
tx: schistosoma
praziquantel
Schistosoma disease
liver and spleen granulomas causing portal hypertension
clonorchis sinensis transmission
undercooked fish
Sx: clonorchis sinensis
fluke causing biliary tract infection with pigmented (brown) gallstones
assoc’d with cholangiocarcinoma
tx: clonorchis
praziquantel
paragonimus westermani transmission
fluke from undercooked crab meat
sx paragonimus westermani
lung inflammation and secondary bacterial infection with hemoptysis
hemoptysis parasite
paragonimus
microcytic anemia with a parasite
ancylostoma, necator (hook worm
liver cyst, parasite
echinococcus granulosus
vitamin B 12 deficiency parasite
diphylloborhtrium
biliary tract disease parasite
clonorchis sinensis
subacute sclerosing encephalitis sx
ataxia
myoclonus
visual problems
