FINAL MICROBIO MUST KNOWS

Aeromonas hydrophila

Cut glass appearance

Actinomyces israelii

Branching/Beading appearance

Actinomyces

Younger colonies: Spiderlike or wooly | Older colonies: Molar tooth appearance

Aggregatibacter actinomycetemcomitans

Star shaped colonies

Bacillus anthracis

Box-Car, Medusa Head/comet tail | Inverted fir tree appearance in semi-solid medium

Bacillus anthracis

Beaten egg white consistency

Bacillus anthracis | Legionella pneumophila

Ground glass appearance

Bifidobacterium spp.

Bifurcated/forked ends

Bordetella spp.

Mercury droplet colonies

Cardiobacterium hominis

Flowerette/Rosette

Chromobacterium violaceum

Dark/ very dark purple smooth colonies on blood agar due to VIOLACEIN (purple pigment)

Corynebacterium diptheriae

Club shaped appearance, palisades ("picket fence") or "Chinese letters"

Corynebacterium diptheriae

Poached egg colonies

Corynebacterium diptheriae | C. pseudotuberculosis | C. ulcerans

Black colonies with brown halo on CTBA and Tinsdale agar

Eikenella corrodens | Kingella

Pitting of agar

Enterobacter spp.

Pink colonies with dark center on EMB "FISH EYE"

Escherichia coli

Beta hemolytic on SBA | Green metallic sheen on EMB

Erysipelothrix rhusiopathiae

Test tube brush/bottle brush grown on stab culture

Fusobacterium nucleatum

Speckled colonies

Fusobacterium nucleatum | Nocardia

Bread crumb colonies, pointed/tapered end

Haemophilus ducreyi

School of fish appearance

Haemophilus influenzae

Dew drop colonies with Satellitism

Klebsiella | Enterobacter

Mucoid colonies (due to capsule)

Legionella

Ground glass colonies

Listeria monocytogenes

"Umbrella shaped" pattern of motility on semi solid medium, Blue-green on McBride agar

Moraxella catarrhalis

Hockey Puck Colonies, Wagon wheel-like

Mycoplasma hominis (spp)

Fried Egg Colonies

Mycobacterium bovis

Water droplet colonies

Mycobacterium tuberculosis

Cauliflower-like colonies

Mycobacterium xenopi

Bird's nest colonies

Mycobacterium ulcerans/leprae

Cigar pocket arrangement

Pseudomonas aeruginosa

May exhibit metallic sheen on BAP

Prevotella | Porphyromonas | Veiolonella

Red fluorescence

Serratia

Red pigmented colonies

Streptobacillus moniliformis

Puff/Fluff balls appearance

Streptococcus pneumonia

Young: Dome shaped colonies | Old: Depressed center, Umbilicated due to autolysis

Ureaplasma urealyticum

Granular dark brown clumps

Vibrio cholerae

Yellow on TCBS (due to sucrose fermentation) | Other species: Blue-green

Yersinia enterocolitica

Bull's eye colonies (dark red or burgundy centers surrounded by a translucent border) on CIN agar

Yersinia pestis

Safety pin appearance

Yersinia pestis

Stalactite growth on broth (clumps of cells adhere to one side of the tube)

Yersinia pestis

Pinpoint after 24 hours on SBA but exhibit a rough, cauliflower appearance at 48 hours

Staphylococci

Gram-positive cocci in grapelike clusters

Pyogenic Streptococci

Gram-positive cocci in pairs and short chains

Nonpyogenic streptococci

Gram-positive cocci in long chains

Streptococcus pneumoniae

Gram-positive lancet shaped diplococci

Enterococcus spp.

Gram-positive cocci mostly in chains and pairs

Neisseria spp.

Gram-negative kidney bean shaped diplococci

Corynebacterium

Gram-positive irregularly shaped, pleomorphic, club like

Listeria, Erysipelothrix

Gram-positive rods

Nocardia, Actinomyces

Gram-positive branching rods with filaments

Vibrio

Gram-negative curved, comma shaped short rods

Campylobacter

Gram-negative curved, thin, rods that may be S-shaped, seagull shaped or corkscrew shaped, spiral shaped

Yersinia | Pasteurella multocida

Gram-negative rod with bipolar staining (closed safety pin appearance)

Enterics

Gram-negative bacilli

Pseudomonas

Gran-negative thin bacilli

Haemophilus

Gram-negative small bacilli

Spirillum

Rigid helical rod

Spirochete

Flexible helical rod

Haemophilus ducreyi

School of fish, railroad tracks or fingerprint appearance

Cryptococcus neoformans

Starburst pattern in CSF

S. aureus

Golden-yellow

E. coli

Green metallic sheen on EMB

Pseudomonas

Metallic sheen on BAP

Porphyromonas, Prevotella, Veillonella

Red fluorescence

S. maltophilia

Lavender green, light purple

N. flavescens

Yellow pigment

S. marcescens

Red pigment

C. violaceum

Violet pigment

Listeria monocytogenes

Tumbling

Campylobacter

Darting

Capnocytophaga | Mycoplasma (no flagella)

Gliding

Proteus | Bacillus cereus

Swarming

T. pallidum

Flexing

Leptospira

Spinning

Spirochetes

Corkscrew

B. henselae | Kingella

Twitching

Vibrio spp.

Shooting star