Microbiology Bacteria Identification

Serratia

"Late lactose fermenter" on MAC, ONPG positive, produces brick red pigment, definite identification requires biochemical panel, DNAse positive, IMViC - - + +

Strep viridans

Alpha- hemolytic strep that lack a lancefield group, biochemicall negative, rule out other alpha hemolytic strep, optochin negative, 6.5% NaCl and BE negative

Vibrio cholerae

BAP produces smooth gray white colonies, MAC produces clear colonies, lactose negative, TCBS produces yellow colonies, strait or curved Gram negative rods, motility positive - polar or peritrichous flagella, oxidase positive, serotyping

Strep agalactiae

BHSB, Beta hemolysis, Bacitracin resistant - no zone of inhibition, Serotyping, Hippurate hydrolysis positive, CAMP test positive

Staph aureus

Beta hemolysis, Latex agglutination positive, Catalase positive, Coagulase positive, DNAse positive, Mannitol salt positive, PYR negative

V. vulnificus

Blue- green colonies on TCBS, positive for lactose fermentation

Coagulase Negative Staph (CNS)

Gamma hemolysis, Latex agglutination negative, Coagulase Negative, Mannitol Salt Negative - grows but does not ferment mannitol

H. (aggregatibacter) aphrophilus

Gram negative coccobacilli, normal flora in oral cavity, capnophilic, does not require X or V for growth, HACEK organism

Moraxella catarrhalis

Gram negative diplococci, Carbohydrate utilization - asaccharolytic, DNAse positive, must to BL on all isolates - most are positive

C. diphtheria

Gram positive rods, chinese letters or palisades, "picket fence", black on tellurite, metachromatic stain positive, urease negative, Elek toxin test

Strep pneumonia (SPE)

Gram stain - lancet shaped gram positive diplococci, Alpha hemolysis, Optochin sensitive - zone of inhibition of at least >14mm, Neufeld Quelleng Reaction positive, Bile solubility - colonies will disappear

Strep pyogenes

Group A strep, Beta hemolysis, bacitracin sensitive - any size zone of inhibition indicates the presence of BHSA, Serotyping, PYR hydrolysis positive, SXT resistant - no zone of inhibition

Actinobacillus (aggregatibacter) actinomycetemcomitans

HACEK organism, colonies have star formation, only HACEK that is catalase positive

Kingella species

HACEK organism, ferments glucose and maltose

C. koseri

IMViC + + - +

K. oxytoca

IMViC + - + +

C. freundii

IMViC - + - +

K. pneumoniae

IMViC - - + +, mucoid (capsule), "bubble gum" colonies

Citrobacter

K/A or A/A on TSI, Lysine Decarboxylase negative, Motility positive, differentiate species by indole

Escherichia coli O157:H7

MAC with Sorbitol (SMAC), does not ferment sorbitol and produces clear colonies, serotype - agglutination with O157 and H7 antisera

Yersinia species

MAC- NLF, CIN agar - bulls eye colonies with red centers and clear edges, incubate stool using cold enrichment method, requires group of reactions for ID

Group D Non-enterococci

May be alpha, beta or gamma hemolysis, Bile Esculin Hyrolysis positive, 6.5% NaCl negative, PYR hydrolysis negative, sensitive to penicillin

Group D Enterococci

May be alpha, beta or gamma hemolysis, Bile Esculin Hyrolysis positive, 6.5% NaCl positive, PYR hyrolysis positive, resistant to penicillin, serotyping if beta hemolytic

Micrococcus

Microdase positive, oxidation positive, fermentation negative

H. parahemolyticus and H. parainfluenzae

Normal Flora, only require V for growth

Staph saprophyticus - member of CNS

Novobiocin resistant - produces a zone o less than 16mm

H. ducreyi

Only X is required for growth, gram negative coccobacilli, "school of fish"

Morganella

PAD positive, Urea positive, Ornithine decarboxylase positive, H2S negative, definite identification requires biochemical panel

Providencia

PAD positive, urea variable - P. rettgeri is positive other species is negative, H2S negative, ornithine decarboxylase negative, definite identification requires biochemical panel

Erysipelothrix

Slender gram positive rods that form chains, non-sporeformer, catalase negative, test tube brush motility, H2S positive - turns media black

Proteus

Swarming colonies on BAP, NLF- MAC, PAD positive, motility positive, K/A with gas and H2S on TSI, Urea positive, Lysine negative, differentiate species by indole

V. parahemolyticus

TCBS - blue- green colonies, Serotype using O antisera, growth in high salt concentration - 7-8% NaCl

Haemophilus Species

Tiny, pleomorphic gram negative coccobacilli, motility negative, aerobic or facultative anaerobes, oxidase and catalase positive, reduce nitrates to nitrites, Capnophilic, Fastidious, Factor X and V

Aeromonas

beta hemolytic on BAP, usually lactose postive on MAC, Straight not curved rods, oxidase positive, indole positive, glucose fermentation with production of gas

H. aegyptius

both require X and V for growth, oxidase positive, indole and xylose negative

Eikenella corrodens

colonies pit agar and smell like bleach, infections due to human bite, HACEK organism

Bacillus anthracis

forms chains that fist snugly together "bamboo", forms spores, non-hemolytic, negative motility, lecithinase positive, contaminants or other species are beta hemolytic and motility positve

Neisseria gonorrhoeae (GC)

gram negative diplococci, motility negative, aerobic and capnophilic, chocolate agar, Modified Thayer Martin for selective media - usually see small gray colonies after 2 days, oxidase positive, glucose positive with carbohydrate utilization test

Campylobacter jejuni

gray spreading colonies on CAMPY agar, oxidase positive, curved gram negative rods with S or "seagull" shape, hippurate hydrolysis positive, catalase positive, naladixic acid inhibited, cephalothin resistant, white blood cells present in stool direct gram stain

P. mirabilis

indole negative

P. vulgaris

indole positive

Cardiobacterium hominis

indole positive, HACEK organism

Enterobacter

lactose fermenter on MAC, motility positive, ornithine decarboxylase positive,

Klebsiella

lactose fermenters, negative motility, negative ornithine decarboxylase, differentiate species by indole

Nocardia

long, branching chains of Gram positive rods, partially acid fast, reddish purple filaments, catalase positive, motility negative

Shigella sonnei

most commonly isolated species in the US, ONPG positive, ornithine positve

Shigella species

non lactose fermenter on MAC and HE, K/A on TSI, negative for Gas and H2S, urea negative, motility negative, serotyping

Edwardsiella

non lactose fermenter on MAC, IMVIC ++--, TSI, K/A with gas and H2S

Salmonella

non lactose fermenter on MAC, IMViC - + - +, K/A with gas and H2S on TSI, urea negative, motility positive, lysine decarboxylase positive, serotyping

Plesiomonas

non-hemolytic on BAP, usually lactose positive on MAC, Straight gram negative rods that occurs singly, pairs, or short chains, oxidase positive, indole positive, glucose fermentation with gas, lysine and ornithine decarboxylase positive (purple color)

Listeria only pathogenic source is L. monocytogenes

non-sporeforming gram positive rods, may appear as cocci, beta hemolytic on BAP, Catalase positive, produces tumbling motility in broth, produces umbrella shaped motility in semi-solid agar, rectangular shape zone of hemolysis on CAMP test, hippurate hydrolysis positive, cold enrichment method

N. meningitidis

oxidase positive, glucose and maltose positive with Carbohydrate utilization test

H. influenza

pleomorphic, gram negative coccobacilli, grow on chocolate agar but MAC, require X and V, smooth, gray colonies, with "mousy" odor, oxidase positive, indole and xylose positive

Helicobacter pylori

rapid urea positive, breath test

H. hemolyticus

require x and v for growth, Normal flora

C. jeikeium (JK)

resistant to most antibiotics

C. ureolyticum

urease positive