340 terms


Everything microbiology

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Gram Stain Procedure
1. crystal violet
2.water rinse + iodine
3. water rise + decolorize w/ alcohol
4. counterstain w/ safranin
Gram Positive Cells
2 layers = Inner membrane + outer thick peptidoglycan layer (crosslinked disacchardes via transpeptidase aka penicilin binding protein)
TEICHOIC ACID in cell wall
Gram Negative Cells
3 layers = inner membrane + periplasmic space+ thin peptidoglycan layer (contains murein protein and disaccharides) + outer membrane with LPS (contains endotoxin lipid A, core polysaccharide, O specific side chain)
Overview of Bacterial Classes
Gram positives:
- 3 gram + cocci = streptococcus, enterococcus, staphylococcus
-4 gram + rods = bacillus & clostridium (spores), corynebacterium & listeria (no spores)
-1 gram negative (diplo) cocci= nisseria
-1 spiral gram negative = spirochetes (too small to actually stain)
-mycobacteria = acid fast
-mycoplasma = no cell wall so no staining
India Ink Stain
Identifies crytococcus fungus- mucopolysaccharide capsule looks like clear halo, narrow based budding
Staph epidermidis on catheters
Facultative intracellular organisms that can survive inside macrophages/neutrophils
Listen Sally Yer Friend Bruce Must Leave
Francisella tularensis
Clostridium tetani
rigid paralysis, continuous muscle contraction, lockjaw, neurotoxin
Clostridium botulinum
inhibits Ach release, flaccid paralysis, neurotoxin
vibrio cholera
watery diarrhea, AB- enterotoxin, increases cAMP, raw oysters/shellfish
oxidase +, grows in alkaline, comma shaped, gram -, flagella
shigella dysenteriae
AB- enterotoxin, kills intestine epithelium, bloody diarrhea, hemolytic uremic syndrome
invasive, cell to cell, non-motile, non-lactose fermenting
Enterohemorrhagic E.coli (EHEC 0157H7)
shiga like toxin, enterotoxin, kills intestine epithelium, bloddy diarrhea, hemolytic uremic syndrome
strep pyogenes
beta hemolysis, pyogenic toxin, scarlet fever, toxic shock like syndrome, tissue invasive hemolysins/streptolysins cause abscess, impetigo, necrotizing fascitis, rheumatic fever
staph aureus
toxic shock syndrome toxin- fever, rash, desquamation scalded skin, food poisoning due to preformed exotoxin, shock; tissue invasive toxins cause abscess, skin infection like carbuncles, yellow pigment
clostridium perfingens
Alpha toxin lecithinase hydrolyzes lecithin in membrane causing gas gangrene
bacillus anthracis
toxin causes edematous black eschar cutaneously
1. Protective antigen- binding
2. Edema factor- increases cAMP
3. lethal factor- inactivates protein kinase, kills
corynebacterium diphtheriae
AB-toxin, ADP ribosylates elongation factor 2 (EF2) blocking protein translation- pharyngeal "pseudo- membrane" and "bull neck" CNS deficits, targets heart causes myocarditis
pseudomonas aeruginosa
exotoxin A blocks elongation factor2 (EF2) blocking protein translation- targets liver
clostridium difficile
AB toxin destroys enterocyte cytoskeleton, pseudomembranous enterocolitis, antibiotic associated diarrhea (clindamycin and ampicillin especially)
look for toxins in stool to diagnose
spore forming anaerobic, Rx = metronidazole/ oral vancomycin
Bordetella pertussis
whopping cough, AB toxin increases cAMP levels, damages respiratory epithelium
4 bacteria that increase cAMP levels
C= cholera
A= anthrax
M= montezuma's revenge aka enterotoxigenic e.coli (ETEC)
P = pertussis
naked DNA fragments from one bacteria after lysis gets incorporated into a closely related bacteria's genome
naturally competent bacteria
are able to undergo transformation naturally include
strep. pneumoniae
H. flu
when a bacteriophage (virus that infects bacteria) brings DNA from one bacteria into another
generalized = the phage is only carrying DNA from the first bacteria
Specialized = splicing error and a piece of bacterial DNA + phage virus DNA is packaged and delivered to a new bacteria "lysogenic conversion" how E.coli gets new capabilities
Major mode of acquiring antibiotic resistance, F plasmids allow for exchange of the plasmid to another F- bacteria and gets incorporated into the DNA creating a new F+ bacteria = HFr (high frequency recombinant) bacteria. This new recombinant genome can be transferred again either whole or "accidentally" spliced and transferred in pieces
mobile genetic elements, transfer genetic material from non-homologous bacterial species, how bacteria from different genera acquire resistance from each other ie staph from enterics
Catalase positive
test distinguishes between staph and strep
Beta hemolysis
Complete lysis of RBC, clear rings, classification for strep
Alpha hemolysis
partial RBC lysis leaves a green zone, classification for strep
Strep pyogenes/Group A strep
beta hemolytic
bacitracin sensitive (growth inhibited)
Virulence: M protein (adherence, anti-phagocytosis)
causes: pharyngitis, impetigo, pyoderma, cellulitis, necrotizing fasciitis, erysipelas, scarlet fever, TSLS, rheumatic fever, and glomerulonephritis
Rx:= Penicilin G/V, erythromycin, (+ clindamycin for deep skin infections)
Group B strep (strep agalactiae)
beta hemolytic, meningitis/pneumonia/sepsis in BABIES acquired peri-natally, normal part of vaginal flora
Rx =Ampicillin penicillin G DURING labor
viridans strep
alpha hemolytic
WILL grow if optochin is present (not afraid of- the- chin "optochin")
virulence: dextran (binding to fibrin on damaged heart valves)
found in the mouth, dental infection, cavities(s. mutans) , liver or brain abscess, subacute (slow) endocarditis in damaged heart valves
Rx = penicillin G
Strep intermedius
in the strep viridans group, if you find this in the blood look for an abscess somewhere!! Do a contrast CT
Enterococci/ Used to be in Group D strep
normal bowel flora, grows in 40% bile or 6.5% NaCl, cause UTI, biliary infections, endocarditis, and sepsis from indwelling catheters, implicated in nosocomial infections, resistance to vancomycin from VanA transposon (VRE)
Rx = ampicillin + aminoglycoside
vancomycin resistant = linezolid, daptomycin, nitrofurantoin
Strep Bovis/Group D strep
... in the blood beware of CANCER IN THE COLON, grows in 40% bile, found in GI tract
Rx = ampicillin + aminoglycoside
Strep pneumoniae
gram positive diplococci, bacterial pneumonia and meningitis in adults, otitis media in children, virulence = polysaccharide capsule
alpha hemolytic
quellung reaction
optochin sensitive (won't grow if present)
Rx = Penicillin G, erythromycin, ceftriaxone, vaccine
bugs that cause otitis media
strep pneumo 30%
H flu 25%
moraxella catarrhalis 15-20%
Features of Staphylococci
catalase positive, gold pigment on sheep blood agar, beta hemolytic
Staphylococcus aureus
coagulase positive, catalase positive, beta hemolytic, colonizes nasopharynx
Tissue invasion via hyaluronidase, lipase, staphylokinase, protease
causes: pneumonia, meningitis, osteomyelitis, UTI, ACUTE endocarditis (IV drugs), arthritis, skin infections (abscess, carbuncle/faruncle, cellulitis)
exotoxins cause:
gastroenteritis (24 hr food poisoning)
TSS- TSS-1 toxin (tampons)
Scalded skin syndrome- exfoliatin toxin (babies around cut bellybutton)
Rx= MRSA Vancomycin, daptomycin, clindamycin, TMP-SMX, linezolid
Coagulase positive
this test distinguishes staph aureus
staph epidermidis
catalase positive, coagulase negative, skin flora, biofilms of prosthetic devices/catheters
Rx = vancomycin
Staph saprophyticus
catalase positive, coagulase negative, gamma hemolytic, UTI in sexually active women
Rx = penicillin
E. coli EHEC
0157:H7 most common- shiga like toxin, HUS (hemolytic anemia, thrombocytopenia, renal failure) no sorbitol fermentation
E. coli EPEC
Diarrhea in children- no toxin, adheres to apical surface and flattens villi preventing absorption
E.coli ETEC
Traveller's diarrhea (montezuma's revenge)- watery
labile toxin- increases cAMP
stable toxin- increases cGMP
both cause increased fluid in lumen and diarrhea
E.coli EIEC
Invasive- bloddy diarrhea and fever looks just like shigella b/c both invade
Bacillus cereus
food poisoning from RE-HEATED RICE!!- emetic type heat stable
diarrheal type- associated with meat-heat labile
Gram - rod
Aspiration pneumonia in alcoholics and diabetics, currant jelly sputum,
Abscesses in lungs/liver
Campylobacter jejuni
bloddy diarrhea, leading cause of food borne illness from puppies, poultry, unpasturized milk, S-shaped, oxidase +, grows in heat 42 degrees Celsius, gram -

Associated with Guillian- Barre, Reiter's reactive arthritis
Yersinia enterocolitica
diarrhea and mesenteric adenitis transmitted from pork, pets, and milk
secretes a toxin that increases increases cGMP leading to diarrhea (can be bloody if bacteria invades)
has a urease, causes stag horn massive calculi in renal pelvis, UTI, very motile can't even be grown well on media
ammonium Mg phosphate kidney stones
Giardia lamblia
bloating, flatulence, foul smeling fatty diarrhea, HIKERS & CAMPERS ingest cysts in water

dx- look for trophozoites or cysts in stool
rx- metronidazole
Entamoeba histolytica
invasive bloody diarrhea, liver abscess, RUQ pain, creates a "flask-shaped" ulcer on histology in submucosa, ingest cysts from water

dx- look for for trophozoites with RBCs in cytoplasm or cysts with multiple nuclei in stool or do serology for ab/ag
rx- metronidazole kills trophozoites, iodoquinol kills cysts
severe diarrhea in AIDS pts
mild diarrhea in everyone else
ingest cysts from water- filtered out in city water supply
dx- cysts on ACID FAST stain
Toxoplasma gondii
CATS! brain abscesses in HIV, ring enhancing lesions seen with imaging
crosses placenta causing congenital - chorioretinitis, hydrocephalous, intracranial calcification, pregnant women avoid cats!
found in CAT feces and meats

dx- serology, biopsy
rx- sulfadiazine + pyrimethamine
Naelgleria fowleri
rapidly fatal meningitis after swimming in fresh water enters via nose and penetrates cribiform plate
dx- amoebas in CSF
rx- amphotericin B
Trypanosoma brucei gambiense
African sleeping sickness- lymphadenopathy, recurring fever, somnolence, encephalitis, coma
get from Tsetse fly painful bite
dx- look for organism on blood smear
rx- suramin for blood disease, melarsoprol for CNS infection
Trypanosoma brucei rhodesiense
African sleeping sickness- lymphadenopathy, recurring fever, somnolence, encephalitis, coma
get from Tsetse fly painful bite
dx- look for organism on blood smear
rx- suramin for blood disease, melarsoprol for CNS infection
Plasmodium vivax
48 hr cyclic fever, headache, hemolysis (anemia), splenomegaly, can be dormant in liver, transmitted by anopheles mosquito
dx- look for trophozoite ring form in RBC or RBC schizont filled with merozoites
rx- Chloroquine + primaquine for dormant form in liver
if resistant use mefloquine
image shows ring form
Plasmodium ovale
48 hr cyclic fever, headache, hemolysis (anemia), splenomegaly, can be dormant in liver, transmitted by anopheles mosquito
dx- look for trophozoite ring form in RBC or RBC schizont filled with merozoites
rx- Chloroquine + primaquine for dormant form in liver
if resistant use mefloquine
image shows schizont containing merozoites
Plasmodium falciparum
most severe form of malaria- irregular cyclic fevers, can cause cerebral malaria (attack the brain capillaries) no dormant form
Plasmodium malariae
72 hr cyclic fevers
fever, hemolytic anemia, transmitted by IXODES TICK (same as lyme's disease- co-infection common) occurs in northeast USA
dx- look for ring form trophozoite or maltese cross form merozoite in RBCs
Trypanosoma cruzi
Chagas' disease- BIG organs, in South America, REDUVIID BUG "kissing bug" painless bite scratch the feces into our skin
dilated cardiomyopathy
dx- look for bug on blood smear
rx- nifurtimox
Leishmania donovani
SANDFLY transmission, causes visceral (kala-azar) and cutaneous leishmaniasis (ulcers that heal super slowly) - spiking fevers, hepatosplenomegaly, pancytopenia
dx- look for macrophages that contain amastigotes
rx- cutaneous = sodium stibogluconate,
visceral =liposomal amphoterecin B
trichomonas vaginalis
protozoal vaginitis- smells fishy, green discharge, itching and burning, STI
dx- look for trophozoite on wet mount will be motile
rx- metronidazole for patient and partner
Provides rigid support against osmotic pressure, consists of cross linked sugars
Lipoteichoic acid is found in
gram positive bacteria
Endotoxin/LPS is found in (lipid A)
gram negative bacteria
This later is very thick in gram positives
peptidoglycan - stains with crystal violet so gram positives look blue/purple
this layer is very thin in gram negatives
Found only in gram negatives, site of endotoxin (LPS, lipid A)
outer membrane
Site of oxidative and transport enzymes in bacteria
plasma membrane
space between the cytoplasmic membrane and the outer membrane in gram negative bacteria, contains beta lactamases
location of beta lactamases in gram negatives
protects bacteria against phagocytosis
encapsulated bacteria
Even Some Pretty Nasty Killers Have Shiny Bodies
strep pneumo
Nisseria men.
Klebsiella pneumo
H. flu
Salmonell typhi
B strep
adherence to cell surface
bacterial form that is resistant to dehydration, heat, and chemicals
separate DNA segment encodes for bacterial resistance, enzymes, and toxins can be transferred during conjugation
mediates adherence to foreign surfaces such as indwelling catheters
Lacks a cell wall will not gram stain
contains mycolic acid and high lipid content in cell wall, only stains acid fast
tissue- blue, bacterium- red
Intracellular bacteria that don't gram stain
Cell wall is too thin to gram stain
Silver stain used for
H. Pylori
Ziehl Neelsen (carbol fuschin) stain used for
Acid fast organisms- Nocardia, mycobacterium
PAS (periodic acid schiff) stain
stains glycogen and mucopolysaccharides
diagnoses Whipple's disease (treponema whipplei)
Giemsa stain identifies
Quellung reaction
Identifies capsule- swelling if capsule is present
Diptheria Toxin
toxin encoded by beta prophage, inactivates elongation factor 2 (EF-2)- will see pharyngeal membrane, don't scrape it
elek's test for toxin
What can happen if you scrape the diptheria pseudomembrane?!
it bleeds and the toxin gets into the bloodstream and blocks protein synthesis in the heart and nerve cells especially-bad stuff! Don't scrape it
pseudomonas exotoxin
exotoxin A- inactivates elongation factor 2 (EF2), blocks protein synthesis leads to host cell death, aerobe
Shigella exotoxin
toxin- cleaves rRNA inactivates 60s ribosome unit- blocks protein synthesis
EHEC exotoxin
shiga-like toxin cleaves rRNA inactivates 60s ribosome unit blocking protein synthesis
Toxins in ETEC
heat labile toxin- increases cAMP- increases Cl- secretions in gut water follows causing watery diarrhea
heat stable toxin- increases cGMP- reduces NaCl resorption in gut leads to watery diarrhea
vibrio cholerae exotoxin
toxin- increases cAMP by inactivating Gs receptor leading to increased Cl- secretion into gut
Bordetella pertussis exotoxin
toxin- increases cAMP by inhibiting Gi receptor (inhibits the inhibitor) impairs phagocytosis so microbe can survive
clostridium tetani exotoxin
toxin- cleaves SNARE protein required for neurotransmitter release prevents release of inhibitory GABA and glycine causing rigid paralysis
clostridium botulinum exotoxin
toxin- cleaves SNARE protein required for neurotransmitter release, prevents release of Ach, flaccid paralysis
clostridium perfringens exotoxin
Alpha toxin- phospholipase that degrades cell membranes and tissues leading to gas gangrene
strep pyogenes exotoxins
alpha toxin- hemolysis
beta toxin- sphingomyelinase
gamma toxin- hemolysis and leukocidin functions
leukocidin- destroys leukocytes
Enterotoxins A-E- food poisioning
TSST-1- superantigen toxic shock syndrome
epidermolytic/exfoliative- scalded skin syndrome
Strep pyogenes exotoxins
ASO titers
exotoxin A- a superantigen that causes scarlet fever, rash, shock also called erythrogenic/pyogenic toxin
Streptolysin S- oxygen stable, hemolysis
Streptolysin O- oxygen labile, hemolysis
what is the pigment of actinomyces israelii
yellow- sulfur granules
what color is the pigment produced by staph aureus
what color is the pigment produced by pseudomonas
what color is the pigment produced by serratia marescens
gram +, branched filament, anaerobe, causes oral or facial abscesses that drain through sinuses
rx = penicillin
gram +, branched filament, acid fast aerobe
treat with sulfonamides
gram + cocci, catalase positive, coagulase positive, yellow pigment
staph aureus
gram + (diplo)cocci, catalase negative, alpha hemolysis, optochin sensitive, positive quellung
strep pneumoniae
gram + cocci, catalase negative, alpha hemolytic, optochin resistant
viridans strep
gram + cocci, catalse negative, beta hemolytic, bacitracin sensitive
strep pyogenes
gram + cocci, catalase negative, beta hemolytic, bacitracin resistant
Group B strep (strep agalactiae)
gram + cocci, catalase negative, gamma hemolysis, grows in bile AND 6.5% NaCl
Group D strep (enterococcus)
gram + cocci, catalase positive, coagulase negative, novobiocin sensitive
staph epidermidis
gram + cocci, catalase positive, coagulase negative, novobiocin resistant
staph saprophyticus
gram positive rods
bacillus (facultative aerobe)
mycobacterium (acid fast)
Jones Criteria for Rheumatic Fever
Due to strep pyogenes
J- joints (migratory polyarthritis)
<3- Carditis (pan carditis)
N- Nodules (subcutaneous)
E- Erythema marginatum (pink rings on trunk/limbs-spares face)
S- Syndenham's chorea (St. vitus dance)
Leptospira interrogans
found in water contaminated with animal urine
causes flu like symptoms + photophobia with conjunctivitis + jaundice
seen in surfers in the tropics
weil's disease- severe complication jaundice and azotemia, hemorrhage and fever
Borrelia Burgdorferi
cuses disease transmitted from Ixodes tick in NE USA
mouse as reservoir
stage 1 disease- erythema migrans (bulls eye w/ central clearing) + flu
stage 2- neurologic and cardiac symptoms (bells palsy, AV node block)
stage 3- encephalopathy, chronic monoarthritis usually in knee

Rx = doxycycline for stages 1-2, ceftriaxone for stage 3
Erythema migrans
characteristic skin manifestation seen in lyme's disease
borrelia burgdoferi red border with central clearing can look like a target
Treponema pallidum
has 3 stages of disease, can also be congenital
diagnose by giving non-treponemal VDRL screening test that detects beef cardiolipin released from cells due to treponema damage confirm with treponemal test FTA-Abs test that looks for antibodies
rx= penicillin G (doxycycline if allergic)
primary syphilis
painless chancre on genitalia
secondary syphilis
disseminated disease- fever, fatigue
maculopapular rash on palms and soles
condyloma lata with treponema seen on dark-field microscopy
tertiary syphilis
gummas (chronic granulomas)
aortitis (tree barking of ascending aorta)
tabes dorsalis- posterior column disease
charcot joints- impaired sensation, damaged joints
argyll- roberton pupil- accomodates but doesn't react
congenital syphilis
saber shins (anterior tibial bowing)
saddle nose
hutchinson's teeth (notching of incisors)
mulberry molars
Jarisch herxheimer reaction
flu like syndrome that occurs when you begin treatment for syphilis due to killed treponema releasing pyrogens
salmonella typhi
causes rose spots on abdomen fever, headache, diarrhea, stays latent in gallbladder
motile, hematogenous spread, produces hydrogen sulfide, antibiotics prolong it so supportive rx only, invades intestinal mucosa causing bloody diarrhea, non-lactose fermenter
spore forming bacteria
coxiella burnetti
listeria monoytogenes
facultative intracellular microbe acquired by eating unmasturized milk/soft cheeses, deli meats
-form actin rockets that move between cells
-pregnant women beware vaginal transmission during birth can cause neonatal meningitis
or spontaneous abortion
rx = ampicillin
woolsorter's disease
inhalation anthrax- flu like symptoms that rapidly progress to hemorrhage, mediastinitis, and shock
mycobacterium tuberculosis
-primary TB- asymptomatic or mild illness that leads to resolution or latent infection- gohn complex (hilar nodes + calcified TB gohn focus in middle lobe)
-secondary TB- reactivation more severe symptoms (fever, hemoptysis, night sweats) with extra pulmonary manifestations
- milliary TB- severe disseminated bacterimia
-progressive lung disease in HIV and malnourished pts ends in death
mycobacterium kansaii
causes pulmonary TB like symptoms in someone with chronic bronchitis/COPD
Agar required to culture TB
lowenstein- jensen
Acid fast stain, weakly gram positive
Diagnosing TB
chest xray- look for lesions, hilar nodes
serial (3x) early morning sputum to stain acid fast bugs
culture- takes long uses lowenstein jensen agar
mycobacterium leprae
Hansen's disease
lepromatous- BAD! TH2 mediated, highly contagious, lethal, diffuse skin manifestation and disfigurement b/c peripheral nerves affected and you can't tell that you have injured yourself
tuberculoid- milder, hairless skin plaques, TH1 mediated
Treatment for leprosy
dapsone + rifampin + clofazimine for 2-5 years (lepromatous)
dapsone + rifamin 6 months (tuberculoid)
cat scratch disease
regional lymphadenopathy
borellia recurrentis
recurrent fever due to variable surface antigens
from Lice and ticks
undulant fever
from unpasteurized dairy and cows
pregnant women beware!
chlamydophila psittaci
parrots, birds give you this
coxiella burnetti
Q fever, presents as pneumonia
from spores (aerosols) of cattle/sheep placenta and amniotic fluid- why would I play with sheep placenta?!
Ehrlichia chaffeensis
non-rash rickettsial disease, flu- like illness, monocytes with berry like morula inclusions in cytoplasm
from lone star tick
Francisella Tularensis (tularemia)
rabbits give you this (also ticks, deer fly)
potential agent for biological warfare
Pasteurella multocida
osteomyelitis, cellulitis caused by cat/dog bite
Rickettsia prowazekii
causes EPIDEMIC typus
trasmitted by louse
rash starts centrally and spreads outward sparing palms and soles
rx = doxycycline
rickettsia rickettsii
causes rash on soles and palms starts on wrists and ankles and spreads to trunk
trasmitted by DERMACENTOR tick
rx = doxycycline
rickettsia typhi
ENDEMIC typhus
transmitted on fleas
rash starts centrally and spreads outward sparing palms and soles
rx = doxycycline
yersinia pestis (plague)
fleas on prairie dogs (and rats) in the southwest will give you this
Gardnerella vaginalis
gram variable rod, causes bacterial vaginosis- gray discharge, painless, fishy smell, clue cells (epithelial cells covered in bacteria irregular edges)
not and STD but associated with sex somehow
rx= metronidazole
wheal felix test
antibody agglutination test for rickettsial infections
will be positive in erlichosis, RMSF, and all of the rickettsial typhus infections (r. tickettsii, r. typhi, r. prowazekii)
will be negative in Q fever (coxiella) because it is grouped with rickettsial infections but doesn't really belong there no antigens present
treatment for all rickettsial diseases
Bugs that cause atypical pneumonia
legionella pneumophilia
chlamydophila pneumoniae
mycoplasma pneumo.
chlamydia trachomatis serotypes D-K
causes reactive arthritis, neonatal conjunctivitis or pneumonia, non-gonococcal urethritis, PID, ectopic pregnancy due to scarring
chlamydia trachomatis serotypes A-C
chronic infection that causes follicular conjunctivitis (blindness) in Africa
chlamydia trachomatis serotypes L1-L3
causes lymphogranuloma venereum-
primary ulcers and inguinal lymphadinitis
rectal disease that can look like IBD
chlamydia treatment
azithromycin or doxycycline- because their cell wall lacks peptidoglycan
remember these bugs don't gram stain because they are intracellular, use giemsa
mycoplasma pneumoniae
-causes atypical "walking" pneumonia in young people (especially groups like in the military and prisons)
-lacks cell wall, doesn't gram stain
-X-ray will look worse than the patient (not that sick)!!!
-forms cold agglutinins (IgM)
-Grown on Eaton's agar
rx= macrolide or fluroquinolone (penicillins won't work because has no cell wall duh)
Mycoplasma pneumonia
the only bacteria whose cell membrane contains cholesterol (sterols) for stability
Enterobius vermicularis
roundworm, children, anal puritis, scotch tape test
get it from consuming eggs
rx= benazole or pyrantel pamoate
Ascaris lumbricoides
giant roundworm, fecal-oral transmission, intestinal infection that has a life cycle involving larval penetration of bowel wall traveling in blood to lungs, cough them up, swallow the larvae, mature in gut
rx = bendazole or pyrantel pamoate
Strongyloides stercoralis
roundworm, larvae in soil penetrate the skin, life cycle goes through bloodstream to the lung,cough them up and swallow them and they mature in gut,
rx=IVERMECTIN or albenazole
ancylostoma duodenale
roundworm larvae penetrates skin, life cycle through bloodstream to lungs, cough them up and swallow them, mature in gut
-latch on to gut wall and suck your blood causing anemia
rx= bendazoles or pyrantel pamoate
Necator americanus
roundworm larvae penetrates skin, life cycle through bloodstream to lungs, cough them up and swallow them, mature in gut
-latch onto gut wall and suck your blood causing anemia
rx= bendazoles or pyrantel pamoate
dracunculus medinensis
tissue roundworm contracted from drinking water causes skin inflammation and ulceration
rx= slowly extract the worm
onchocerca colculus
tissue roundworm from female black fly bite causes hyperpigmented skin (black nodules) and river blindness
rx= Ivermectin
Loa Loa
tissue roundworm from flies causes swelling in skin worm in conjunctiva
rx = diethylcarbamazine
Wucheria bancrofti
tissue roundworm transmitted from female mosquito larvae migrates to lymphatics and blocks it up causing elephantiasis
rx = diethylcarbamazine
Loeffler's eosinophilic pneumonitis
eosinophilic pneumonia caused by helminthic parasites whose life cycle passes through the lungs
trichinella spiralis
worm acquired from eating undercooked pork or bear (wild game) larvae go from GI to muscle causing myositis, periorbital edema, eosinophilia, see cysts in muscle biopsy
rx= bendazoles
Taenia solium
pork tapeworm
ingest larvae from undercooked pork-->intestinal infection
ingest eggs from human feces--> cysticercosis in tissues esp brain (ex = immigrant with new onset CNS symptoms)
rx= praziquantel (bendazoles for neurocysticercosis)
diphyllobothrium latum
fish tapeworm steals all of your vitamin B12 causing deficiency and megaloblastic anemia with neuro symptoms
rx= praziquantel
Echinococcus granulosus
dog tapeworm get it from dog feces- eggs will hatch in your GI, enter circulation, form mature larval cysts in LIVER
-causes liver cyst/abscess if the fluid leaks causes anaphylaxis

rx= benazoles + surgically remove them (inject with ethanol first to kill worms and prevent anaphylaxis)
tenia saginata
beef tapeworm does NOT cause cysticercosis
rx= praziquantel
Schistosoma mansoni
blood fluke, snail host, penetrates skin causing swimmer's itch will travel with mesenteric vessels to the GI can cause liver and spleen granulomas (classically in caribbean and south america) gets stuck in vessels causing PORTAL HTN
rx= praziquantel
Schistosoma haematobium
blood fluke, snail host, penetrates skin causing swimmer's itch, will travel to lower urinary tract causing squamous cell carcinoma of the bladder (classically in Egyptians)
rx= praziquantel
clonorchis sinensis
liver fluke get it from undercooked fish, lives in biliary tract linked to cholangiocarcinoma
rx= praziquantel
paragonimus westermani
trematode (fluke) acquired from undercooked crab meat causes lung inflammation and hemoptysis
rx= praziquantel
Features of systemic mycoses
all of the fungi are dimorphic
cold (20 degrees C)= mold
heat (37 degrees C) = yeast
all cause pneumonia but can also disseminate
local treatment = itraconazole or fluconazole
systemic big gun = amphoterecin B
can mimic TB granulomas but remember TB granulomas are caseating and the fungi won't spread from person to person
systemic mycosis causes pneumonia
Mississippi & Ohio river valley
Bird or bat guano, spelunkers in caves
will see macrophages filled with the fungi that are smaller than RBCs
systemic mycosis found in states east of the Mississippi and in central america
causes inflammatory disease of lung, skin, and bone
BROAD BASED BUDDING (about same size as RBC)
systemic mycosis found in southwest US, San Joaquin valley or deserts especially after earthquakes and sand storms
causes pneumonia and meningitis!
-exists as a barrel shaped conidia (mycelia) in soil that formed a spherule filled with endospores in lungs
systemic mycosis found in latin america
forms budding yeasts with a captains wheel formation
causes severe pneumonia and mucosal/skin granuloma
Malassezia furfur
fungus that causes tenia versicolor causes degragation of melanocytes leading to hypo/hyper-pigmented patches on skin in hot humid weather and on sun exposed areas
-spaghetti and meatball appearance on KOH prep
treat with selsun (selenium sulfide), and topical miconazole
microsporum trichophyton
dermatophytes fungal skin infections = tines (pedis, cruris, corporis, capitis) puritic lesions with central clearing
see mold on KOH prep NOT dimorphic
dermatophytes fungal skin infections = tines (pedis, cruris, corporis, capitis) puritic lesions with central clearing
see mold on KOH prep NOT dimorphic
dermatophytes fungal skin infections = tines (pedis, cruris, corporis, capitis) puritic lesions with central clearing
see mold on KOH prep NOT dimorphic
tenia unguium
nail fungus causes onychomycosis
requires more intense oral antifungal treatment for several months (topical alone usually not enough)
candida albicans
opportunistic yeast causes oral and esophageal thrush and vulvovaginitis, under skin folds in obese patents
- found in neonates, immunocompromised, those who use inhaled steroids
- RX =
-topical azole for vulvovaginal
-fluconazole or caspofungin for oral/esophageal
-fluconazole, amphotericin B, caspofungin for systemic
aspergillus fumigatus
invasive mold especially in immunocompromised (harbinger of death in these patients) also seen in people with chronic granulomatous disease and in lungs
forms fungus balls
narrow septate hyphae that branch at acute angles
Cryptococcus neoformans
heavily encapsulated yeast that causes meningitis especially in HIV
found in soil, pigeon droppings
will see soap bubble lesions in brain
india ink stain
latex agglutination test for the polysaccharide
Sabouraud's agar
opportunistic fungus often seen in diabetic keotacidosis that forms black eschars on the palate and in nasal mucosa causes headache and facial pain enters by piercing the cribiform plate
broad irregular non-septate hyphae branching at right angles
opportunistic fungus often seen in diabetic keotacidosis that forms black eschars on the palate and in nasal mucosa causes headache and facial pain enters by piercing the cribiform plate
broad irregular non-septate hyphae branching at right angles
pneumocystis jirovecii
yeast that causes diffuse interstitial pneumonia with ground glass appearance in immunocompromised diagnosed by lung biopsy or bronchiolavage
sporothrix schenckii
rose gardener's disease
dimorphic, cigar shaped fungus that lives on plants (roses) and in moss
causes local pustules/ulcers that follow lymphatic tracts
treatment = potassium iodide or itraconazole
Amphotericin B aka amphoterrible due to side effects
big gun for systemic fungal infections
binds ergosterol in fungi and forms pores in their membranes
toxicity = fevers, chills, hypotension, NEPHROTOXIC (hydrate the patient!!) arrhythmias, anemia, IV phlebitis must supplement Mg and K because alters renal tubules
treatment for cryptococcal meningitis
amphotericin B _/+ flucoytosine
binds ergosterol in fungi and forms pores in their membranes can only be used topically because too toxic when given systemically
"swish and swallow" for candidiasis
inhibits fungal ergosterol synthesis by blocking the specific P450 enzyme that makes it
used for local and systemic mycoses
especially for cryptococcus and candida
inhibits fungal ergosterol synthesis by blocking the specific P450 enzyme that makes it
used for local and systemic mycoses
causes gynecomastia !!!
inhibits fungal ergosterol synthesis by blocking the specific P450 enzyme that makes it
used for topical /local infections
inhibits fungal ergosterol synthesis by blocking the specific P450 enzyme that makes it
used for topical/ local infection
inhibits fungal ergosterol synthesis by blocking the specific P450 enzyme that makes it
used for blastomycosis, coccidiodes, and histoplasmosis
inhibits fungal ergosterol synthesis by blocking the specific P450 enzyme that makes it
used for aspergillus
side effects of azoles
these antifungals can cause inhibition of testosterone synthesis and gynecomastia and liver dysfunction because they inhibit a cytochrome P450 also results in drug interactions
antifungal that inhibits DNA and RNA biosynthesis by conversion to 5 fluorouracil
used in systemic mycoses
antifungal that inhibits cell wall synthesis by blocking synthesis of beta glucan
used to treat aspergillosis and candida
antifungal that inhibits cell wall synthesis by blocking synthesis of beta glucan
used to treat aspergillosis and candida
inhibits fungal enzyme squalene epoxidase thereby inhibiting ergosterol synthesis
used to treat dermatophytoses especially onychmycosis
antifungal that interferes with microtubule function disrupting mitosis, only deposits in keratin containing tissues (nails, skin) so ideal for dermatophytosis
toxicity = teratogen, carcinogen, increases metabolism of warfarin, OCPs, and antiseizure meds
blocks detoxification of heme into hemozoin and the heme accumulates and is toxic to plasmodia
resistance occurs when the plasmodia acquire a pump that reduces the intracellular concentration of the drug
toxicity = retinopathy
4 most common causees of UTI
staph saprophyticus
proteus mirabilis
Medications used to treat UTI
trimethoprim sulfamethoxazole
aminopenicillins (ampicillin, amoxicillin)
tests used to diagnose UTI
leukocyte esterase test = bacterial
nitrite test = gram negative bacteria
green metallic sheen on EMB agar
motlity causes swarming colonies, produces urease, struvite nephrolith
proteus mirabilis
osteomyelitis in diabetic
Nisseria meningitidis
gram negative diplococci
maltose fermenter
Nisseria gonorrhoeae
gram negative diplococci
does not ferment maltose
causes waterhouse- friderichsen syndrome
nisseria meningitis
waterhouse-friderichsen syndrome
Sepsis, DIC, adrenal hemorrhage
caused by nisseria meningitidis
What grows pink colonies on MacConkey's agar
gram negative lactose fermenters
citrobacter, klebsiella, E.coli, enterobacter, serratia
they produce beta-galatosidase which cleaves the lactose into glucose and galactose
IgA protease
secreted by
H. flu type B
cleaves immunogloblulin found in mucosa allowing them to colonize respiratory mucosa
M protein
virulence factor produced by group A strep to prevent phagocytosis
Protein A
virulence factor expressed by staph aureus that binds to Fc region of Ig and prevents phagocytosis (opsonization)
H. flu culture requirements
chocolate agar with factor V (NAD) and factor X (hematin) required for bacterial growth
mom goes to the nickel and dime store to buy chocolate when her child has...
Nisseria culture requirements
Thayer-Martin (or VPN) media
Vancomycin (inhibits gram positives)
Polymyxin (inhibits all other gram negatives)
Nyastatin (inhibits fungi)
B. pertussis culture requirement
Bordet-Gengou potato agar
C. diptheriae culture requirement
cysteine tellurite plate- black colonies grow
loffler's media
Agar required to culture M. pneumoniae
Eaton's Agar
Eosin methylene blue agar
grows metallic green E.coli colonies
Agar required to grow legionella
charcoal yeast extract buffered with cysteine and iron
agar required to grow fungi
sabouraud's agar
MacConkey's agar
identifies lactose fermenting bacteria, will grow pink colonies on this
D-glutamate polypeptide capsule
anthrax capsule and virulence factor
treatment for Nisseria gonnorrhoeae
ceftriaxone + azithromycin or doxycycline to cover for concurrent chlamydia infection
Haemophilus influenzae
causes epglottitis in children can also cause meningitis that you treat with ceftriaxone
symptoms of epiglottitis caused by H. flu
cherry red
difficulty swallowing and breathing
thumb sign on xray
Vaccine for H. flu
contains the Type B capsular polysaccharide conjugated to diptheria toxoid or to another protein
legionella pneumophila
severe pneumonia with fever, GI, and CNS symptoms, hyponatremia!!
gram negative rod seen on silver stain
treat with macrolide or quinolone
legionalla pneumophila
causes pontiac fever - mild flu like symptoms
Pseudomonas aeruginosa
causes pneumonia in cystic fibrosis patients
Pseudomonas aeruginosa
cause of otitis externa, malignant type with characteristic granulation tissue
Pseudomonas aeruginosa
causes sepsis with black skin lesions
Pseudomonas aeruginosa
bacteria associated with burns and wound infections
Pseudomonas aeruginosa
bacteria associated with hot tub folliculitis
and contact lens wearers
Pseudomonas aeruginosa
aerobic gram negative rod, oxidase positive
produces pyocyanin, motile, non-lactose fermenting
Pseudomonas aeruginosa
bacteria that has a grape like odor
Salmonella complication
causes osteomyelitis in sickle cell patients
Nisseria gonorrhoeae
most common causes of septic arthritis in young adult males
H. pylori
gastritis and duodenal ulcers
urease positive
triple therapy for H. pylori
clarithromycin + amoxicillin (or metrodinazole) + PPI
quadruple therapy for H. pylori
metrodinazole + tetracyclin + PPI + bismuth
superoxide dismutase
enzymes that obligate anaerobes lack
meningococcal infection prophylaxis
Rifampin (especially for children)
Gonorrhea prophylaxis
Syphilis prophylaxis
Penicillin G
History of recurrent UTI prophylaxis
prophylaxis for subacute endocarditis during dental procedures
penicillins, aminopenicillins, cephalexin
prophylaxis in pregnant women who carry group B strep in vaginal flora
prevention of post-surgical staph aureus infection
prevention of gonococcal or chlamydial conjunctivitis in newborn
erythromycin eye drops
Gray baby syndrome
chloramphenicol causes this
treats anaerobes ABOVE the diaphragm
clindamycin works better here
treats anaerobes BELOW the diaphragm
metronidazole works better here
typical features of DNA viruses
double stranded, linear, icosahedral, replicate in nucleus
acyclovir/ valacyclovir
antiviral used to treat HSV1, HSV2, VZV, EBV
antiviral preferred to treat VZV
also effective for HSV1/2
Ganciclovir/ valganciclovir
antiviral used especially to treat CMV
antiviral used to treat when ganciclovir fails to treat CMV or in acyclcovir resistant HSV
general features of herpes viruses
lie dormant in ganglia or in cells, cause painful vesicular skin eruptions, are enveloped DNA viruses linear dsDNA, acquire envelope by budding through nuclear membrane
causes gingivostomatitis, keratoconjunctivitis, TEMPORAL LOBE ENCEPHALITIS, painful labial vesicular skin eruption, remains latent in TRIGEMINAL GANGLIA
causes painful vesicular eruption in genital region or oral mucosa, causes neonatal infection by perinatal transmission, remains latent in sacral ganglia
varicella zoster virus (VZV)
primary infection = chicken pox
reactivation = zoster (dermatomal, won't cross midline)
remains latent in dorsal root gangia trigeminal ganglia
spread by respiratory secretion
infects B cells and causes large cytotoxic Tcell response resulting in aytpical lymphocytes = Downy cells, that often hug RBCs
posterior cervical lymphadenopathy
exudative pharyngitis
hepatosplenomegaly (avoid contact sports)
Monospot test
detects EBV virus heterophile antibodies by agglutination of sheep or horse RBCs
what causes heterophile negative mono-like illness
acute HIV
acute toxoplasmosis
viral hepatitis
strep pharyngitis
What happens when you treat EBV with aminopenicillins (amoxicillin,ampicillin)
full body puritic rash
does not indicate an allergic reaction to amoxicillin or ampicillin normal reaction following administration of this drug when you have this infection
Malignancies associated with EBV
Hodkin's lymphoma
Burkitt's lymphoma
nasopharyngeal carcinoma
diffuse large B cell lymphoma
"owls eye" inclusion in nucleus
most common congenital TORCH infection, pneumonia, retinitis
remains latent in mononuclear cells
Cowdry type A bodies
inranuclear eosinophilic droplets seen in HSV1, HSV2, VZV
causes roseola (sixth disease or exanthem subitum)
3-5 days of high fevers followed by diffuse macular rash, often has febrile seizures
causes Kaposi's sarcoma
causes purple lesions on skin and in organs
Tzanc Test
smear of open vesicle shows multinuclear giant cells
seen in HSV1, HSV2, VZV
dsDNA virus, partial circular genome
causes HBV
has a reverse transcriptase
linear dsDNA virus
sore throat
acute hemorrhagic cystitis
sore throat
Parvovirus B19
linear ssDNA virus, smallest DNA virus,
slapped cheek rash - fifths disease in children (erythema infectiosum)
hydrops fetalis and miscarriage in fetus
Parvovirus B19
linear ssDNA virus, smallest DNA virus,
RBC aplasia and rheumatoid arthritis-like syndrome in adults
circular dsDNA virus
JC virus causes progressive multifocal leukoencephalopathy (PML) in HIV patients
Papilloma virus types 1,2,6,11
circular dsDNA virus that causes warts on the skin (1,2) and on the genitalia (6,11)
papilloma virus types 6,18
circular dsDNA virus thatcauses cervical canter, anal cancer, penile cancer
linear dsDNA virus, largest DNA virus
causes milkmaid blisters
confers resistance to smallpox
small pox
linear dsDNA virus, largest DNA virus
eradicated but could be used in germ warfare
Molluscum contagiosum
linear dsDNA virus, largest DNA virus
causes flesh colored dome lesions with central dimple- self limited lesions that resolve on their own
Rotavirus (reovirus family)
nonenveloped, icosahedral, linear, dsRNA virus
leading cause of fatal diarrhea in children globally
most commonly seen in daycares in the winter
Coltivirus (reovirus family)
nonenveloped, icosahedral, linear, dsRNA virus
causes Colorado tick fever
spread by wood tick
causes self-limited flue like illness
rhinovirus (picornavirus family) & coronavirus
viruses that cause the common cold
poliovirus (picornavirus family)
non-enveloped, icosahedral, linear, ssRNA virus
attacks the gray matter of the ventral horn of the spinal cord and motor neurons in the pons and medulla leading to paralysis
Salk vaccine
killed injectable polio vaccine
Sabin vaccine
live oral polio vaccine
Echovirus (picornavirus family)
non-enveloped, icosahedral, linear, ssRNA virus
causes aspetic meningitis, summer URI outbreaks
Coxackievirus (picornavirus family)
non-enveloped, icosahedral, linear, ssRNA virus
causes aseptic meningitis and herpangina (fever, mouth blisters) and myocarditis
Coxackievirus (picornavirus family)
causes hand foot and mouth disease
vesicular lesions on the soles and palms
HAV (picornavirus family)
this form of hepatitis is caused by a non-enveloped, icosahedral, linear, ssRNA virus
fecal oral spread
this form of hepatitis is caused by a non-enveloped, icosahedral, linear, ssRNA virus of the hepevirus family
fecal oral spread
Calicivirus (Norovirus)
non-enveloped, icosahedral, linear, ssRNA virus
causes point source outbreaks of vomiting and diarrhea on cruise ships and nursing homes
this form of hepatitis is in the flavivirus family
enveloped, icosahedral, linear, ssRNA
Yellow Fever (flavivirus family )
enveloped, icosahedral, linear, ssRNA
transmitted by Aedes mosquito
human or monkey revervior- fatal in up to 50%
causes high fever, black vomitus, hemorrhagic disease (epistaxis, hematemesis, petechiae), jaundice
seen in subsaharan Africa and South America-get vaccine for endemic areas
Dengue fever (flavivirus family)
enveloped, icosahedral, linear, ssRNA
most prevalent mosquito borne illness worldwide
Break bone fever- severe muscle and joint pain with retro-orbital headache and fever
hemorrhagic fever is serious complication
Tourniquet test
field test for thrombocytopenia indicating the development of hemorrhagic fever in Dengue fever
inflate the blood pressure cuff and look for excessive bruising
St. Louis encephalitis (flavivirus family)
flavivirus, enveloped, icosahedral, linear, ssRNA
arbovirus that causes encephalitis
West Nile virus (flavivirus family)
enveloped, icosahedral, linear, ssRNA
bird reservoir, mosquito vector, humans are incidental host
causes flu-like illness
in 1/150 infected people can cause meningitis and encephalitis by attacking the ventral horn motor nuclei leading to paralysis and death
treatment is supportive
Rubella (Togavirus family)
enveloped, icosahedral, linear, ssRNA
causes fever, postauricular lymphadenopathy, arthralgias, fine truncal rash that starts at the head and moves down
congenital infection associated with PDA, and pulmonic stenosis
Eastern equine enephalitis/ western equine encephalitis
arbovirus of the togavirus family that causes encephalitis
HTLV - causes T cell leukemia
these use reverse transcriptase
Influenza (orthmyxovirus family)
enveloped, helical, linear, negative sense ssRNA virus
antigens =
-hemagglutinin (promotes viral entry)
-neuraminidase (promotes progeny virion release)
increased risk of bacterial superinfection is responsible for mortality associated with this virus
undergoes rapid genetic change
Genetic (antigenic) Shift
Oh shift!
reassortment of the viral genome (like when human recombines with swine virus)
causes pandemics
Genetic Drift
minor genetic changes based on random mutation leads to seasonal variation and minor epidemic
parainfluenza (paramyxovirus family) Croup
enveloped, helical, linear, negative sense ssRNA
causes laryngo-tracheo-bronchitis in children:
barking seal cough, respiratory distress, inspiratory stridor, chest X ray shows steeple sign (subglottic narrowing)
rx = humidifiers, racemic epinephrine, single dose of dexamethosone, oxygen as needed
RSV (paramyxovirus family)
enveloped, helical, linear, negative sense ssRNA
causes brassy cough, bronchiolitis, and pneumonia in babies especially during the winter
has a fusion protein on the surface of the virus that allows it to bind to other cells forming a syncitium
rx - premies or baby with chronic lung disease give passive immunity palivizumab
zanamivir, oseltamivir
inhibit influenza neuraminidase
treatment and prevention of influenza in high risk patients
treatment used for hepatitis C
inhibits synthesis of guanine nucleotides by competitive inhibition of IMP dehydrogenase
Rubeola (measles, paramyxovirus family)
enveloped, helical, linear, negative sense ssRNA
koplik spots on buccal mucosa
descending maculopapular rash
Rubeola (measles, paramyxovirus family)
causes subacute sclerosis panencephalitis due to a mutated virus years after infection with this virus
can also cause giant cell pneumonia
Rubeola (measles, paramyxovirus family)
enveloped, helical, linear, negative sense ssRNA
coryza (runny nose)
Mumps (paramyxovirus family)
enveloped, helical, linear, negative sense ssRNA
causes parotitis, orichitis, and aseptic meningitis
Rabies virus (rhabdovirus family)
following animal bite (bat, dog, raccoon, skunk)
long incubation period (weeks to months)
symptom progression = fever malaise--> agitation, photophobia, hydrophobia --> paralysis, coma, death
virus takes a retrograde path up nerve axons to reach the CNS
bullet shaped virus
Negri bodies
characteristic inclusions seen in rabies virus
found in cytoplasm of neurons
listeria monocytogenes
gram positive rod with tumbling motility
can cause meningitis or sepsis in immunocompromised or neonatal meningitis
rx = ampicillin (amp-gent in neonates usually covers it)
Mechnism of action of albendazole "bendazoles"
inhibits microtubule assembly in worms
Ivermectin mechanism of action
activates GABA receptors leads to worm paralysis and expulsion
Praziquantel mechanism of action
increases calcium influx in worms causing parasite contracture and then relaxation
corynebacterium diptheriae
gram positive rod with metachromic (blue,red) granules
Nisseria meningococci
rifampin for prophylaxis (or cipro/ceftriaxone)
ceftriaxone or penicillin G for treatment
Treatment for pseudomonas
aminoglycoside (ie gentamicin) + extended spectrum penicillin (ie piperacillin, ticarcillin)