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USMLE Gram Positive

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xovepaza's version from 2015-04-20 18:59

Taxonomy

OrganismStainShape
StaphylococcusGram+Cocci
StreptococcusGram+Cocci
NeisseriaGram-Cocci
ClostridiumGram+Rods
CorynebacteriumGram+Rods
BacillusGram+Rods
ListeriaGram+Rods
MycobacteriumStrong acid fastRods
GardnerellaGram variableRods
NocardiaWeak gram/acid fastBranching filamentous
ActinomycesGram+Branching filamentous
Escherichia coliGram-Rods
SalmonellaGram-Rods
ShigellaGram-Rods
YersiniaGram-Rods
KlebsiellaGram-Rods
ProteusGram-Rods
EnterobacterGram-Rods
SerratiaGram-Rods
VibrioGram-Rods
CampylobacterGram-Rods
HelicobacterGram-Rods
PsuedomonasGram-Rods
BacteriodesGram-Rods
HaemophilusGram-Pleiomorphic
LegionellaGram-/silverRods
BordatellaGram-Coccoid rod
FrancisellaGram-Rods
BrucellaGram-Coccoid rod
PasteurellaGram-Coccoid rod
BartonellaGram-Rods
RickettsiaGram-/GiemsaPleiomorphic
ChlamydiaeGram-/GiemsaPleiomorphic
LeptospiraGram-Spirochetes
BorreliaGram-Spirochetes
TreponemaGram-Spirochetes
MycoplasmaGram-No cell wall
Moraxella catarrhalisGram-Cocci
H influenzaeGram-Coccoid rod
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Identifying Tests

TestIDMnemonic
Don't Stain WellTreponema/Rickettsia/Mycobacteria/Mycoplasma/Legionella pneumophila/Chlamydia6 These Rascals May Microscopically Lack Color
GiemsaChlamydia/Borrelia/Rickettsiae/Trypanosomes/Plasmodium5 Certain Bugs TRY my Patience
SilverFungi (Pneumocystis)/Legionella/Helicobacter pylori3
Ziehl-Neelsen/carbol fuchsinAcid fast (Nocardia/Mycobacterium)2
Thayer-Martin/VPN/Vancomycin/Polymyxin/Nystain mediaN gonorrhea/meningititis2
Pink colonies on MacConkey's agarLactose fermenting enterics (Citrobacter/Klebsiella/E coli/Enterobacter/Serratia/etc)5 macConKEE'S agar/lactose is KEE
Obligate aerobesNocardia/Pseudomonas aeruginosa/Mycobacterium tuberculosis/Bacillus4 Nagging Pests Must Breath
Obligate anaerobesClostridium/Bacterioides/Actinomyces3 Can't Breath Air
Obligate intracellularRickettsia/Chlamydia2 stay inside when it is Really Cold (can't make own ATP)
Facultative intracellularSalmonella/Neisseria/Brucella/Mycobacterium/Listeria/Francisella/Legionella/Yersinia pestis8 Some Nasty Bugs May Live FacultativeLY
Encapsulated bacteriaStreptococcus pneumoniae/H influenzae type B/Neisseria meningitidis/E coli/Salmonella/Klebsiella pneumoniae/group B Strep7 SHiNE SKiS
Catalase+Pseudomonas/Listeria/Aspergillus/Candida/E coli/S aureus/Serratia7 PLACESS for your CATs
Urease+Cryptococcus/H pylori/Proteus/Ureaplasma/Nocardia/Klebsiella/S epidermidis/S saphrophyticusCHuck norris hates PUNKSS
IgA protease (allows respiratory mucosal colonization)S pneumoniae/H influenzae type B/Neisseria3 SHiN
Methenamine silverFungi (Pneumocystis)/Legionella/Helicobacter pylori3
No pink colonies on MacConkey's agarLactose nonfermenters/Shigella/Salmonella/Proteus/Pseudomonas/H pylori5 SSPPhP
Oxidase+Moraxella/H pylori/Neisseria/Pseudomonas/C jejuni/vibrio Cholera6 M/HNPCC
Common in granulomatous diseasePseudomonas/Aspergillus/S aureus/Serratia/Nocardia5 parts of PLACESS plus N(NPASS)
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Identifying Tests

TestIDMnemonic
India inkCryptococcus neoformans (background is dark/org remains transparent)1
Chocolate agar with factors V (NAD+) and X (hematin)H influenzae1/child has flu (not really flu)/goes to five and dime store to buy chocolate
PAS/Periodic Acid SchiffGlycogen/mucopolysaccharides/Whipple's disease (Tropheryma whipplei)PASs the sugar/1 organism
Bordet-Gengou (potato) agarB pertussis1
Tellurite plate/Loffler's MediaC diptheriae1
Lowenstein-Jensen agarM tuberculosis1
Eaton's agarM pneumoniae1
Green metallic sheen on Eosin methylene blue (EMB)E coli1
Charcoal yeast extract agar buffered with cysteine and ironLegionella1 French legionnaire w/Silver helmet sitting around campfire (Charcoal) w/Iron dagger is no Sissy (cysteine)
Sabourand's agarFungiSab's a fun guy
Encapsulated bacteria testQuellungcapsular swellung/capsule serves as antiphagocytic virulence factor/antigenic in conjugate vaccines
Yellow sulfur granulesActinomyces israeliihas yellow sand
Gold yellow pigmentS aureusLatin for gold
Blue green pigmentPseudomonas aeruginosaGreen aerugula
Red pigmentSerratia marcescensMaraschino cherries
Protein A (antiphagocytic/opsonization)S aureus1
M protein (prevents phagocytosis)GAS1
Reticulate bodyChlamydia as seen on culture (Elementary is in vivo)1 Reticulate Replicates in cell (culture)/Elementary is small/dense/Enfectious/Enters cells via Endocytosis
Cold agglutininsM pneumoniae1 IgM
Metachromic (blue/red) granulesCorynebacterium diptheriae1 ABCDEFG (G is for granules)
Elek's test for toxinCorynebacterium diptheriae1
Produces hydrogen sulfideSalmonella (to distinguish from Shigella)1
Alkaline mediaVibrio cholerae1
BoxcarBacillus1
Requires cysteineFrancisella tularensis1
Bipolar stainingYersinia pestis1
Signet ring cellStomach cancer (H pylori)1
Novobiocin resistantStaph Saprophyticus1 staph retreat there was NO(vobiocin) StRESs
Novobiocin sensitiveStaph Epidermidis1 staph retreat there was NO(vobiocin) StRESs
Optochin resistantStrep ViridiansOVRPS (overpass)
Optochin sensitiveStrep PneumoniaeOVRPS (overpass)
Bacitracin resistantStrep agalactiaeBBRAS
Bacitracin sensitiveStrep pyogenesBBRAS
GASStrep pyogenes1
GBSStrep agalactiae1
Grows at 42deg CCampylobacter jejuni1 hot CAMPfire
Maltose fermN meningitidis1 MeninGococci ferment Maltose and Glucose
Maltose nonfermN gonorrhoeae1 Gonococci ferment Glucose
Bile soluble (not growth)S pneumonia1
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Bugs with exotoxins

BacteriaToxinMechanismNumberManifestationNumber
Cornybacterium diptheriaeLysogeny acquired Diptheria toxinADP ribosylating A-B toxin/inactivates elongation factor EF-22Pharyngitis with pseudomembranes in throat/severe lymphadenopathy/bull neck4
Pseudomonas aeruginosaLysogeny acquired Exotoxin AADP ribosylating A-B toxin/inactivates elongation factor EF-22Host cell death1
ShigellaShiga toxin/STInactivates 60S/rem A from rRNA2Cytokine release/causes HUS/host cell invasion/GI mucosal damage/dysentery5
Enterohemorragic E coli (EHEC)/incl O157 H7Lysogeny acquired Verotoxin/Shiga like toxin/SLTInactivates 60S/rem A from rRNA2Cytokine release/causes HUS/no host cell invasion3
Enterotoxigenic E coliHeat labile toxin/LTADP ribosylating A-B toxin/overactivates adenylate cyclase/cAMP increases Cl- secretion-H2O efflux3Watery diarrhea/Labile in Air (LT/cAMP)1
Enterotoxigenic E coliHeat stable toxin/STADP ribosylating A-B toxin/overactivates guanylate cyclase/cGMP decreases NaCl and H2O resorption3Watery diarrhea/Stable on Ground (ST/cGMP)1
Bacillus anthracisEdema factorMimics adenylate cyclase1Edematous borders of black eschar in cutaneous anthrax1
Vibrio choleraeLysogeny acquired/Cholera toxinADP ribosylating A-B toxin/permanently activates Gs/overactivates adenylate cyclase/cAMP increases Cl- secretion-H2O efflux4Voluminous rice water diarrhea1
Bordetella pertussisPertussis toxinADP ribosylating A-B toxin/permanently disabling Gi/overactivates adenylate cyclase/impairing phagocytosis4Whooping cough/expiratory cough/inspiratory whoop3
C tetaniTetanospasminCleave SNARE protein req for neurotransmitter release/prevents inhibitory GABA and glycine in spinal cord2Muscle rigidity/lock jaw2
C botulinumLysogeny acquired Botulinum toxinCleave SNARE protein req for neurotransmitter release/prevents stimulatory ACh in neuromuscular junctions2Flaccid paralysis/floppy baby2
C perfringensAlpha toxin/LecithinasePhospholipase degrades tissue/cell membrane1Degradation of phospholipid C cause myonecrosis (gas gangrene)/hemolysis2
C difficileToxin AEnterotoxin binds brush border of gut1Diarrhea1
C difficileToxin BCytotoxin destroyes cytoskeletal structure of enterocytes1Pseudomembranous colitis1
S pyogenesStreptolysin OProtein that degrades cell membrane1Lyses RBC/Beta hemolysis/ASO host antibodies can diagnose rheumatic fever3
S aureusTSST1Brings MHC II-TCR into proximity/overwhelming IFN gamma-IL2 release/shock3TSS/fever/rash/shock4
S pyogenesLysogeny acquired/Erythrogenic/Exotoxin ABrings MHC II-TCR into proximity/overwhelming IFN gamma-IL2 release/shock3TSS/fever/rash/shock4
S aureusExfoliative toxinN/A0SSS1
S aureusEnterotoxinN/A0Food poisoning1
Bacillus cereusCereulideN/A0Food poisoning1
Mycobacterium tuberculosis (and related)Cord factorInhibits macrophage activation by IFN gamma/induces TNF alpha secretion2Tuberculosis1
E coliFimbriaeN/A0Cystitis/pyelonephritis2
E coliK capsuleN/A0Pneumonia/neonatal meningitis2
E coliLPS endotoxinN/A0Septic shock1
N gonorrheaPiliProvides antigenic variation/adhesion2GU infection1
S epidermidisBiofilmAlters surface tension1Prostheses infection1
B anthracisD glutamate capsulePrevents phagocytosis1Anthrax1
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Bacterial genetics

Question Answer Column 3
TransformationCells take up any naked DNA1
Conjugation F+ to F-Cell with plasmid for sex pilus and conjugation replicates plasmid/transfers through pilus/no chromosomal transfer/quick and efficient4
Conjugation Hfr to F-Cell with plasmid for sex pilus and conjugation integrated into chromosome/replicates plasmid and chromosomal genes/transfers through pilus/rarely complete4
TranspositionSelf gene swapping between plasmids/chromosomes2
Transduction generalizedLytic phage infection/bacterial DNA fragmented and packaged into capsid/phage transfers to new cell/many traits may be transferred4
Transduction specializedLytic phage infection/phage DNA excised/flanking bacterial DNA packaged into capsid/phage transfers to new cell/usually same trait transferred to new cells5
Lysogeny (specialized transduction) acquired traitsShigA like toxin/Botulinum toxin/Cholera toxin/Diptheria toxin/Erythrogenic toxin of Strep pyogenes5
Natural transformersSHiN S pneumonia/H influenzae B/Neisseria3
Temperate phage works viaSpecialized transduction/lysogenic instead of lytic/incorporates viral genome into cell3
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Gram positive lab algorithm

Starting groupTestRemaining EntitiesMnemonic
Gram +MorphologyCocci/Bacilli/branching filamentous3
Branching filamentousAnaerobeActinomyces1
Branching filamentousAerobeNocardia1
Branching filamentousAcid fastNocardia1
Branching filamentousNot acid fastActinomyces1
RodsAnaerobeClostridium1
RodsAerobeBacillus1
RodsAcid fastMycobacterium1
CocciCatalase+Staphylococcus1
CocciCatalase-Streptococcus1
CocciGroupingStaphylococcus in clusters/Streptococcus in chains2
StaphCoagulase+S aureus1
StaphCoagulase-S others (epidermidis/saprophyticus)2
Staph/coagulase-Novobiocin resistantSaprophyticus1 staph retreat there was NO(vobiocin) StRESs
Staph/coagulase-Novobiocin sensitiveEpidermidis1 staph retreat there was NO(vobiocin) StRESs
StrepAlpha hemolysis (partial/green)S pneumonia/Viridians streptococci2
StrepBeta hemolysis (full/clear)GAS (pyogenes)/GBS (agalactiae)2
StrepGamma hemolysis (none)GDS (enterococcus/E faecalis)/Nonenterococcus (S bovis)2
Strep/Alpha hemCapsule/quellung+S pneumonia1
Strep/Alpha hemCapsule/quellung-Viridians streptococci1
Strep/Alpha hemOptochin resistantViridiansOVRPS (overpass)
Strep/Alpha hemOptochin sensitivePneumoniaeOVRPS (overpass)
Strep/Beta hemBacitracin resistantGBS (agalactiae)BBRAS
Strep/Beta hemBacitracin sensitiveGAS (pyogenes)BBRAS
Strep/Gamma hemGrowth in bile and 6.5% NaClEnterococcus (E faecalis)1
Strep/Gamma hemGrowth in bile not 6.5% NaClNonenterococcus (S bovis)1
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USMLE Gram Negative
ISP 28 Infectious Disease C ID with Rashes
ISP 28 Infectious Disease K UTI
ISP 28 Infectious Disease L STDs