Micro - Bacteria Flashcards
catalase test
GP
staph (+)
strep (-)
coagulase test
GP
staph aureus (+) staph epidermidis or saprophyticus (-)
novobicin test
GP
staph epidermidis (sens) staph saprophyticus (resis)
hemolysis
GP
streptococci (a, ß, g)
alpha hemolysis
GP
Strep. pneumoniae (capsule)
Strep. viridans (no capsule)
- differentiate btwn the two using optochin + bile solubility
ß hemolysis
GP
Strep pyogenes (grpA)
Strep agalactiae
Staph aureus
Listeria monocytogenes
LAAP = listeria, aureus, agalactiae, pyogenes
gamma hemolysis
GP
enterococcus
non-enterococcus
optochin sensitivity
GP
Strep. pneumoniae - sensitive
Strep. viridans - resistant
bile solubility
GP
Strep. pneumoniae - soluble (lysed by bile)
Strep. viridans - not lysed by bile
bacitracin
GP
S. pyogenes (sensitive)
S. agalactiae (resistant)
growth in bile and 6.5% NaCl
GP
Enterococcus faecalis
growth in bile, not 6.5% NaCl
GP
Strep. bovis
B cells typically infected by this virus
EBV
Ganglion cells typically infected by this virus
herpes
oligodendrocytes typically infected by this virus
JC virus –> PML
Measles –> SSPE
follicular dendritic cells typically infected by this virus
HIV
grows at 42˚C
GN, oxidase +, comma shaped
campylobacter jejuni
grows in alkaline media
GN, oxidase +, comma shaped
vibrio cholera
produces urease
GN, oxidase +, comma shaped
helicobacter pylori
GN diplococci
2
neisseria meningitidis
neisseria gonorrhoeae
differentiate using maltose test
maltose test is used for..
neisseria MeninGitidis (fermenter - maltose + glucose) neisseria Gonorrhoeae (non-fermenter - glucose only)
GN “coccoid” rods
4
haemophilus influenza (requires factor V, X)
Bordtella pertussis
Pasturella - animal bites
Brucella
Requires factor V, X
haemophilus influenza - GN coccoid rods
can also be grown with staph aureus, which provides factor V
lactose fermenters (rate) - Macconkey’s
GN
klebsiella, e. coli, enterobacter (fast fermenter)
citrobacter, serratia (slow fermenter)
MaconKEES
lactose non-fermenters
how do differentiate between them?
All GN
Shigella Salmonella Proteus Yersinia Pseudomonas
Oxidase test - only pseudomonas are oxidase +
oxidase test - which bugs are +? -?
Oxidase (-) Shigella Salmonella Proteus Yersinia
Oxidase (+) Pseudomonas Campylobacter Vibrio cholerae Helicobacter pylori
oxidase +, comma shaped
campylobacter jejuni - grows at 42˚
vibrio cholera - alkaline media
helicobacter pylori - urease
bacterial infection associated with schistocytes
EHEC - eating undercooked meats
Shigella
Staph aureus virulence factor
Protein A - binds Fc-IgG - inhibits complement activation and phagocytosis; colonizes the nose
TSST
superantigen that binds to MHCII and TCR, resulting in polyclonal T cell activation
present in vaginal or nasal tampons
S. aureus food poisoning is due to
preformed ENTEROTOXIN - heat stable (not destroyed by cooking)
S. epidermidis is commonly associated with
What would you treat a hospitalized patient with?
how do you differentiate this from S. saprophyticus?
prosthetic devices
IV catheters
*contaminant of blood cultures
treat with vanco pending sensitivity tests because they can be resistant to multiple antibiotics
SE: Catalase (+), Coagulase (-), Novobicin (S)
SS: Catalase (+), Coagulase (-), Novobicin (R)
S. saprophyticus
at risk for what?
how do you differentiate this from S. epidermidis?
UTI - second most common cause; increased risk of struvite stones (Ammonium MgPO4)
novobicin resistant
SE: Catalase (+), Coagulase (-), Novobicin (S)
SS: Catalase (+), Coagulase (-), Novobicin (R)
S. pneumo
causes
how to differentiate
Meningitis Otitis media pneumonia Sinusitis sepsis in sickle cell patients and splenectomy rusty/reddish brown
a hemolysis (green)
SP: capsule, optochin (S), bile (S)
SV: ø capsule, optochin (R), bile (R)
shape of s. pneumo?
virulence factor?
lancet shaped GP diplococci, encapsulated
IgA protease
s. viridans
how do differenitate it from S. pneumo?
alpha hemolytic, optochin R
can cause
- dental caries (mutans)
- normal inhabitant of the mouth (mitis)
- subacute bacterial endocarditis on damaged valves (sanguinis)
a hemolysis (green)
SP: capsule, optochin (S), bile (S)
SV: ø capsule, optochin (R), bile (R)
how does strep. sanguinis cause subacute bacterial endocarditis
binds to fibrin-platelet aggregates on damaged heart valves
GAS is also known as
S. pyogenes
diseases that S. pyogenes cause
pharyngitis, cellulitis, erysipelas, rheumatic fever, PIGN
things that S. pyogenes produce?
Streptolysin O: degrades cell membranes; lyses RBC
Exotoxin A: superantigen - causes release of IFNg, IL2 –> shock
M protein - prevent phagocytosis virulence factor
S. pyogenes sensitivity?
what must you differentiate it from?
ß hemolysis (clear)
GAS (Spyogenes): Bacitracin (S); ASO titers
GBS (S. agalactiae): Bacitracin (R), Hippurate test (+), CAMP test
GBS is also known as
S. agalactiae
things that S. agalactiae cause?
what happens if you find out that a mother is colonized with GBS within a month of her due date?
neonatal sepsis, meningitis, pneumonia
must give INTRApartum penicillin or ampicillin
GDS is also known as
what does it cause?
what do you have to differentiate it from?
S. Enterococci - cocci chains
subacute endocarditis after GI/GU procedures, can cause UTIs, biliary tract; penG resistant
gamma hemolysis
S. Enterococcus (GDS: E. faecalis, E. faceium): bile and NaCl (+)
S. bovis : bile (+) only
S. Bovis cuases
endocarditis after colonic malignancy
clostridum - different types and what do you normally find them on?
CBotulinum: honey, bottles/canned food
CPerfringens: soil or raw meat, reheated meat dishes
CDiff: antibiotic use (clindamycin or ampicillin”
shape of clostridium?
GP Rod
clostridium tetanus produces
Tetanospasmin - protease that cleaves SNARES –> prevents release of GABA and glycine from Rhenshaw cells in spinal cord –> spasticity/sustained muscle contraction
Clostridium botulinum produces
Botulinum toxin - heat-labile protease that cleaves SNARES –> prevents release of ACh at NMJ –> floppy/descending flaccid paralysis
Clostridium perfringens produces
Alpha Toxin - lecithinase that degrades tissues and cell phospholipid membranes –> myonecrosis/gas gangrene + diarrhea
C diff produces
Toxin A (enterotoxin) binds to brush border of gut
Toxin B (cytotoxin) causes cytoskeletal disruption via actin polymerization –> pseudomembrane –> diarrea
white fibrinous pseudomembrane should make you think of this bug
Corneybacterium diphtheriae
Corneybacterium diphtheriae shape?
what does it produce?
Rod w/ blue+red granules (corn is rod-shaped)
Diphtheria Toxin - AB toxins exotoxin encoded by ß prophage, inactivates EF-2 via ribosylation; predilection for cardiac + neural cells
3 tests that you can use for Corneybacterium diphtheriae
Tellurite agar - dark black, slightly iridescent colonies
Loffler medium - cytoplasmic GRANULES that can be stained w/ aniline dye (methylene blue)
Elek Test for toxin
elongated Rod box-car chains should make you think of..
Bacillus anthracis - Aerobe, spore forming
Bacillus anthracis causes
painless black eschar w/ edematous borders, mediastinal widening
spores can be present on wool
Bacillus anthracis virulence factor
polypeptide capsule (D-glutamate) - antiphagocytic
Edema Factor - mimics adenylate cyclase to incr. cAMP”
reheated rice, pasta should make you think of…
bacillus cereus - GP Rod, spore forming
bacillus cereus produces
Cereulide - preformed toxin –> watery dairrhea
Listeria Monocytogenes - features
GP rod with tumbling motility - rocket tails (actin) that propel them into cells (intracellular)
catalase +, LPS (UNIQUE!!!), ß hemolysis
Listeria Monocytogenes - where is it normally found on?
unpasteurized milk, soft cheeses, deli meats
transplacental or vaginal transmission –> meningitis in neonates and elderly
Mycobacterium - features
GP Rod; mycolic acid w/ high lipid content obligate aerobe (use O2 to generate ATP) - lung apices
reactivation of Mycobacterium is usually due to…
Immunocompromised state or TNFa inhibitors (infliximab or adalimumab)
two virulence factors of mycobacterium?
Cord-factor- inhibits macrophage maturation; induces release of TNFa
Sulfatides (surface glycolipids) - inhibit phagolysosomal fusion
Mycobacterium tubuerculosis symptoms
fever, night sweats, weight loss, hemoptysis
MAC - when does it normally occur? how do you deal with it?
AIDS, CD4 <50; prophylaxis w/ Azithromycin; usually unable to form the caseating granulomas
mycobacterium leprosy - predilection for…
skin/superficial nerves (likes cool temperatures –> causes glove and stocking loss of sensation)
normally found on….armadillos
2 forms of mycobacterium leprosy and when do they normally occur?
lepromatous (low CMI, Th2 response) - more serious forms
tuberculoid (high CMI, Th1 response)
PAS(+) foamy macrophages in intestinal lamina propria should make you think of…
Tropheryma whipplei
symptoms that Tropheryma whipplei cause
cardiac sx, arthralgias, neurologic sx, esp. in older men
long-branching Filaments that resemble fungi
2 - how to differentiate between them?
Actinomyces - anaerobe, NOT acid fast
Nocardia - aerobe, acid fast
actinomyces - features
causes..
treatment?
Oral flora
long-branching Filaments that resemble fungi
obligate ANaerobes, ø catalase or superoxide dismutase (susceptible to oxidative damage)
FOUL smelling
Yellow sulfur granules”
oral/facial abscesses; trmt: pencillin
Nocardia
features
how is it detected?
long-branching Filaments that resemble fungi
obligate aerobe (use O2 to generate ATP Urease (+)
Ziehl-Neelsen (carbolfuchsin/aniline dye) in Acid fast Stain
Neisseria
GN diplococci
1 cause of all UTIs
E. coli…..
E. coli
feature
all produce this
GN rod
encapsulated (K capsule)
Catalase (+)
How can E. coli can be detected?
MacConkee’s agar - pink, fast (lactose fermenter)
EMB plates - purple colonies w/ green metallic sheen
EIEC method of pathogenesis
invasive -> necrosis + inflammation -> dysentery
ETEC method of pathogenesis
trmt?
heat-labile toxin (LT) - increases cAMP
heat stable toxin (ST) - increases cGMP -> watery diarrhea; NO inflammation (travelers)
trmt: loperamide, fluoroquinolones, azithromycin, rifampin “Travelers Love to travel FAR”
EPEC method of pathogenesis
EPEC: pili allows for adheres + flattens vili –> prevents absorption (children)
EHEC 0157:H7 method of pathogenesis
Shiga-like toxin (SLT) - incactivates 60S rRNA (prevents binding of tRNA -> enhances cytokine release -> dysentery + HUS (anemia, thrombocytopenia, ARF, schistocytes due to microthrombi)
usually due to undercooked meats, raw unpasteurized milk
how to differentiate EHEC 0157:H7 from other e. coli?
ø sorbitol fermentation, ø glucorinidase production (compared to the other E. coli).
shigella - features
GN rod
shigella method of pathogenesis
invades intestinal mucosa (M cells of Peyer’s patches) -> PMN infiltration -> dysentery
Shiga Toxin - inactivates 60S rRNA (prevents binding of tRNA) + enhances cytokine release -> HUS
very low ID50
antibiotics may prolong fecal excretion of this bug
Salmonella - Rod, with flagella
Salmonella typhi - pathogenesis
encapsulated - invades intestinal mucosa -> MONOCYTIC infiltration
Vi antigen prevents opsonization and phagocytosis, produces H2S
can disseminate hematogenously
salmonella typhi - clinical features
ROSE spots on abdomen, fever, HA, diarrhea
carrier state in GALL BLADDER; causes typhoid fever
usually due to poultry, meats, eggs
pseudo-appendicitis
cause?
typically affects?
where can it be found?
Yersinia - GN Rod, intracellular
mini-epidemics in children –> pus + blood in diarrhea
PET feces, contaminated milk, pork
Proteus - features
GN Rod - swarming motility on agar
Urease (+), produces H2S - can cause struvite stones/ammonium MgSo4
Klebsiella - features
who does it usually affect?
what does it cause?
treatment?
GN Rod
Urease (+)
lactose fermenter (MacConkee’s - pink, fast)
Encapsulated, MUCOID colonies”
aspiration –> lobar pneumonia (abscess forming) in alcoholics and diabetics
Red-current jelly sputum
trmt: 3rd gen cephalosporin
3rd leading cause of UTI’s - can cause struvite stones/ammonium MgSo4”
Bacteroides
GN Rod, part of GI flora
Obligate Anaerobes, ø catalase or superoxide dismutase (susceptible to oxidative damage), FOUL smelling (short chain FA)
Produce CO2, H2
Serratia
GN Rod
Red pigment
Catalase (+)
MacConkee’s agar - pink, slow
spiral shape, w/ multiple flagella at one pole
H. pylori - “catalase (+), oxidase (+), Urease (+)
creates alkaline environment”
how is H. pylori detected? treated?
Silver Stain
urease breath test (+)
fecal antigen
triple Rx: PPI, clarithromycin, amoxicllin/metronidazole
can cause Guillain-Barre, reactive arthritis
campylobacter
campylobacter - features
comma shaped
oxidase (+)
42˚C
campylobacter - clinical features (how is it transmitted?
bloody diarrhea, esp in children
FECAL-ORAL transmission (poultry, meat, unpasteurized milk)
can cause Guillain-Barre, reactive arthritis
vibrio - features
GN, comma shaped, oxidase (+)
vibrio - types and clinical features
Parahemolyticus: voluminous watery diarrhea
vulnificus: septicemia -> blisters and muscle necrosis on lower extremity
cholera: profuse rice water diarrhea
vibrio cholera - pathogenesis
Cholera toxin - permanently activates Gs -> incr adenylate cyclase -> incr. cAMP -> H2O loss”
how do you grow vibrio cholera?
alkaline media
sputum w/ grape like odor
pseudomonas
Pseudomonas - general features
GN rod Obligate Aerobe Catalase (+), Oxidase (+) Exotoxin A - inactivates EF-2 via ribosylation Blue-green pigment (pyocyanin)
Pseudomonas pathogenesis
Exotoxin A - inactivates EF-2 via ribosylation
same as c. diptheria
how is pseudomonas generally acquired - list at least 4
burns/wounds DM CF water sources (hot tubs, ventilators) indwelling catheters
What does pseudomonas generally cause?
Pneumonia Sepsis External otitis UTI Diabetics/Drugs Osteomyelitis Echthyma gangrenosum cutaneous necrotic disease - usually associated with bacteremia in immunocompromised host
Pseudomonas - treatment
Gentamycin + piperacillin or cefepime
Neisseria - features
what is it grown on?
GN diplococci
Pili for attachment IgA protease (to colonize mucosa)
Thayer-Martin (contains VPN) for isolation
Neisseria M - features
GN diplococci
encapsulated (polysaccharide capsule)
NM: maltose (+), glucose (+)
Neisseria M - route of transmission, clinical picture and treatment
respiratory/oral secretions
petechial rash on trunk, palm, soles
meningitis
Waterhouse-Friderichsen Syndrome
post-exposure prophylaxis: Rifampin, ciprofloxacin, ceftriaxone for contact prophylaxis
trmt: ceftriaxone or penicillin G
Neisseria G - features
GN diplococci
facultative intracellular, in PMNs
Neisseria G - route of transmission, clinical picture and treatment
STD
gonorrhea, septic arthritis, neonatal conjunctivitis, PID, Fitz-Hugh-Curtis Syndrome;
neonates: erythromycin ointment
adults: ceftriaxone (MUST ADD azithro/doxycycline for possible chalmydia coinfection)
c5-c9 deficiency
think Neisseria
Haemophilus features
GN coccoid rods
encapsulated (type B = worst; made w/ polyribosyl-ribitol phosphate)
IgA protease (to colonize mucosa)
Haemophilus - how is it transmitted? what does it cause? how is it treated/prevented?
Aerosol transmission Epiglottitis (cherry red) -> stridor, odynophagia, drooling; lateral CXR: ""thumbs up"" sign Meningitis - treat w/ ceftriaxone Otitis Media Pneumonia
trmt: Amoxicillin w/ clavulanate
Post-exposure prophylxis: rifampin
Prevention: conjugated vaccine “
how do you grow haemophilus?
“Chocolate Agar w. Factors V, X
- or -
grown w/ S. aureus (provides V)”
legionella - features
GN Rod, facultative intracellular
antigen present in urine
legionella - clinical picture
how is it treated?
aerosol transmission from environment: AC, hot water tanks, sprayers at restaurants, grocery stores
causes HYPONATREMIA (SIADH mediated)
Legionnaire’s dz: pneumonia,high fever, GI, CNS sx (typical: smoker w/ 104˚ T, diarrhea, confusion, and sputum w/ very few or ø bacteria but LOTS of PMNs)
Pontiac fever: mild flu
trmt: macrolide, quinolone
how is legionella detected?
Silver Stain
Charcoal yeast w. Cysteine + Iron
B. pertussis - features
coccoid rods, encapsulated
B. pertussis - pathogenesis
Pertussis toxin - disables Gi –> overactivation of adenylate cyclase –> incr. cAMP
-> Whooping cough: “coughing spells” or paroxysms of coughing
how do you grow B. pertussis
Bordet-Genou (potato)
Pasteurella - features
GN coccoid rods
animal bites
Bartonella Henslae - features
clinical picture
treatment
GN Rod
“cat-scratch dz” - tender regional adenomapthy, stellate granulomas w/ central necrosis
ø trmt necessary, but if immunosuppressed, give ciprofloxacin + dox + macrolides
rash (vasculitis) starts at wrists and ankles and then spreads to trunk, palms, and soles.
R rickettsii - Rocky-MTN spotted fever; triad: HA, fever, rash (vasculitis)
rash starts centrally and spreads out, sparing palms and soles
R typhi - endemic (fleas)
monocytes w/ morulae (berry like inclusions)
R ehrlichiosis
granulocytes w/ morulae (berry like inclusions)
R anaplasmosis
Rickettsiae - features and general treatment? How do you detect them?
GN pleomorphic Obligate intracellular (need CoA + NAD+ because they can’t make ATP)
Giemsa stain
trmt: dox
cattle placenta
Coxiella
ovoid GN
spores released from tick feces + cattle placenta –> spores inhaled -> pneumonia; ø rash, ø vector
Chlamydiae
forms?
subtypes?
features?
Elementary body “Enfectious” - Enters cells via Endocytosis
Reticulate body - Replicates via fission and reorganizes into elementary bodies
trachomatis, Pneumoniae, psittaci
Obligate intracellular - can’t make their own ATP
ø muramic acid in cell wall - why is this impt?? DON’T KNOW
reactive arthritis (Reiter), follicular conjunctivitis (dots on inner eye lids), nongonoccal urethritis, and PID
features of this bug
Chlamydiae trachomatis - DK serotype
Chlamydiae trachomatis serotypes
ABC: African, blindness, Chronic infection
DK
women: urethritis/PID/ectopic pregnancy
neonates: staccato cough + conjunctivitis, acquired via vaginal delivery
L1, L2, L3 - lymphogranuloma venereum - painless ulcers on genitals + painful ulcerated inguinal LN “buboes”
chlamydiae trachomatis - how to detect it?
Giemsa
Fluorescent antibody stain
chlamydiae Pneumoniae
atypical pneumonia; aerosol transmission
chlamydiae psittaci
atypical pneumonia; avian (parrots) reservoir
treatment for chlamydiae
azithromycin or doxycline
Borrelia - features
GN spiral shaped
Borrelia - clinical features
how to diagnose it?
PAINLESS erythema chronicum migrans
BAMM Sequelae: Bells, Arthritis, Myocarditis (AV block), Meningoencephalitis
ELISA + WB only if its not clear that it is is Lyme dz
to stain it: Giemsa stain
Borrelia treatment
Doxycycline - 1st line (or ceftriaxone)
children/pregnant women - use amoxicillin
Leptospira features
GN spiral shaped
How is leptospira acquired? What does it cause?
who is it most common in?
contaminated water with animal urine -> leptospirosis (flu, jaundice, photophobia w/ conjunctival suffusion - red eyes)
Weil dz: severe; jaundice, azotemia from liver/kidney dysfunction; fever, hemorrhage, anemia
common in surfers and tropics
Treponema/Syphilis - general features + 3 stages
Treponema/Syphilis - GN Spiral
1˚Painless chancre (1˚)
2˚maculopapular rash on palms/soles, condylomata lata
3˚ gummas, aortitis (vasa vasorum), neurosyphilis (tabes dorsalis), Argyll Robertson Pupil “Prostitute pupil” - accomodates but does not react to light
How is Treponema/Syphilis diagnosed?
dark field microscopy + Fluorescent antibody staining (FTA-ABS)
How do you know if an infant suffers from Syphilis?
Congenital: saber shins, saddle nose, CN8 deafness, Hutchinson teeth, mulberry molars
treatment for syphilis?
trmt: PenG; can cause Jarisch-herxheimer rxn (flu due to killed spirochetes releasing pyrogens)
gray vaginal discharge w/ fishy smell; not painful
Gardnerella vaginalis - GN rod
Gardnerella vaginalis - features, how is it diagnosed, and treatment
GN rod that causes gray vaginal discharge w/ fishy smell; not painful
Light microscopy - Clue cells - vaginal epithelial cells covered w/ Gardnerella bacteria
trmt: metronidazole or clindamycin
malodorous gray green frothy discharge with inflammation
trichomoniasis
gray vaginal discharge w/ fishy smell; not painful
Gardnerella vaginalis - GN rod
thick, white, adherent discharge “cottage cheese” + inflammation
candida vulvovaginitis
only bacteria that does not have a cell wall
Mycoplasma Pneumoniae
Mycoplasma Pneumoniae - how is it grown?
sterols in membrane for stability - therefore must be grown on Eaton agar - cholesterol
Mycoplasma Pneumoniae - what does it cause? who is it most common in? how do you treat it?
“walking ATYPICAL pneumonia” - insidious onset, HA, nonproductive cough, patchy or diffuse interstitial pneumonia
high IgM titers can agglutinate or lyse RBCs
outbreaks in military recruits, prisons
trmt: macrolide, dox, fluoroquinolone (NOT penicillin, duh)
What is macconkey agar used for? what does it contain
MaConKEE'S agar - contains BILE (inhibits growth of contaminant organisms), but allows growth of lactose fermenters, which show up as pink colonies: Klebsiella E. Coli Enterobacter Serratia
catalase +
Pseudomonas Listeria Aspergillus Candida E coli S. auerus Serratia
Otitis Media
H. influenza
S. pneumo
Morxaella
Otitis Externa
Pseudomonas
Atypical Pneumonia
Mycoplasma
Legionella
Chlamydia
Bloody diarrhea
Campylobacter E. Histolytica EHEC EIEC Salmonella Shigella Yersinia
Watery diarrhea
C. Diff C. perfringens ETEC Protozoa Vibrio cholera Vibrio vulnificus
Pneumonia IVDU or alcholics
S. pneumo, klebsiella, s. aureus
Pneumonia Aspiration
anaerobes
Pneumonia atypical
mycoplasma, legionella, chlamydia
Pneumonia CF
pseudomonas, s. aureus, s. pneumo
Pneumonia nosocomial
s. aureus (MRSA, MSSA), pseudomonas, enterics
Pneumonia post-viral infection
staph, H. influenza, S. pneumo
