GNR unit 3 micro

GNR enterbacteria ex and general

enterobacter, escherichia, shigella, klebsiella, proteus, salmonella, Yersinia, normal flora of instestine GI tract, in nature, most common GNR, opportunistic

endemic to hospitals

enterbac sp (mucoid)., klebsiella sp (mucoid/capsule), serratia sp (red)

overt/ definite/ primary pathogens

always cause infection, shigella, salmonella, yersinia, E. coli O157:H7

Enterobacterales ID

GNR or GNCB (non spore), oxidase - (unless Plesiomonas), glucose fermenters, reduce nitrate to nitrite (3→2), grow pink for lac ferm and clear for non on MAC, normal GI flora GNR inhibited on HE/XLD

Enterobacterales virulence factors

lipopolysaccharide (endo), capsule (adherence, inhib phago), enzyme inactivation (B-lact, carbap, antimicrob resistance)

Enterobacterales- O ag

somatic, part of LPS on outer membrane, used for serotyping

Enterobacterales- K ag

capsular, outside cell envelop, forms bacterial capsule

Enterobacterales- H ag

flagellar, motility, used for serotyping

Enterobacterales isolation

anaerobes- 18-24hrs, ambient air, CO2, or anaerobic

Enterobacterales- colonies

largeer than Staph strep and enterococc, gray, moist, Beta or gamma, can be mucoid swarming red(serratia) pigment

Enterobacterales- MAC

selects for GNR against mixed flora (bile salts and crystal violet inhib GP), differentail- lac ferm low pH pink for E coli, klebsiella, enterobacter, and citrobacter freindii, can use SBA or CHOC for specific stuff

Enterobacterales- EMB

selective, differental- Lact and or sucrose ferm= black or dark centers clear edges, if not colorless, green= e coli

Enterobacterales- shigella salmonella SS agar

used for stool, selective, diff- LF= pink e coli, non= colorless shigella, H2S= black salmonella

Enterobacterales- HE agar

used for stool, selective (higher salt than MAC, inhib GP and normal flora), diff- L or S Ferm= yellow/orange mixed flora, non= colorless shigella, blue green salmonella, H2S= black salmonella, proteus

Enterobacterales- XLD stool culture

selec using sodium deocych on GP and GNR (lower salt good for shigella), diff- lots of lac suc and some xylose, lysine= lys decarb, sodium thrio= H2S

Enterobacterales- XLD normal stool flora

ferment excess carbs (lac suc) inhib decarb of lysin= yellow= e coli, if only ferm xylose do not decarb lysin, ferm lac suc produce H sulf= yellow with black center= proteus

Enterobacterales- XLD pathogenic stool flora

non ferm lac suc xylose= colorless red-pink shigella, ferm xylose then decarb lysind reverting back with cadaverine= red with black centers salmonella

Enterobacterales- SMAC

selec and diff, MAC with lac instease of D-sorb, non ferm= clear e. coli O157:H7, ferm= pink non e coli

Enterobacterales- CIN/YSA

selec/diff (inhib stool orgs), mannitol ferm= pink center clear edges yersinia “bulls eye“, non ferm= clear

Enterobacterales- GN broth

promotes salmonella and shigella, lag phase of growth for most orgs, log phase of growth= SS plate after 6 hrs

Enterobacterales ID process

colony morphology, rapid tests (oxidase, spot indole, PYR), full ID method (GS, MAC growth, oxidase, etc)

mucoid Enterobacterales

klebsiella (capsule), Enterobacter, e. coli (beta hem)

oxidase tests for GNR

neg= no color in 30 sec Enterobacterales, pos= blue purple within 30sec Pseudomonas, Tetramethyl-p-phenylenediamine dihydrochloride, rapid test

spot indole

pos= blue green within 30 sec e coli, kleb oxyt, proteus vulg, citrobac kose, morgan morgan, aeroma, detects bacteral tryptophanase hydrolysis, rapid

PYR

pos= bright red Klebsiella, citrobacter, serratia, enterobacter, yersinai, neg= e coli, rapid

biochem testing process

carb utilization, glucose metabolism (red), amino acid use (decarb dihydro), other

carb utilization- lactose anaerobic fermintation

ferm glucose, B-galact breaks down lactose to pyruvic acid

carb utilization- lactose aerobic oxidation

oxidation of glucose to make CO2 from aerobic respiration of pyruvic acid, Embden myer pathway/glycolysis

carb utilization- lactose non ferm NLF

strictly glucose users of energy

carb utilization- lactose asaccharolytic organisms

use proteins, sulfur, nitrogen, NOT glucose for energy

carb utilization- OF

oil closed tube only show ferm, open shows both

both yellow= just ferm (e coli) or both

closed green= non ferm if open if half yellow ox (pseudomonas)

all green= neither

carb use- TSI

slant agar of glucose, lac and suc, phenol red, sodium thriosulf, ferrois sulf, 18-24 hrs, ferm sugar produce acid and low pH= yellow

TSI carb ferm patterns

K/K= red/red no ferm

K/A= red/yellow gluc ferm

A/A= yellow/yellow gluc lact suc ferm

TSI carb h2s

black if pos, salmonella and Citrobacter freundii

TSI carb gas produc CO2

bubbles or cracked agar

TSI salmonella

K/A red/yellow- gluc ferm, bubbles crack- gas, black- h2s

TSI escherichia coli

A/A yellow- gluc lact suc ferm, bubbles crack- gas

TSI Pseudomonas aeruginosa

K/K red- no ferm

TSI shigella sonnei

K/A red yellow- gluc ferm

carb use- KIA

TSI without sucrose, same results except non lactose ferm but suc ferm Proteus vulgaris= K/A red yellow SF instead of A/A yellow

carb use- ONPG

detects delayed lact F in orgs with B-gala but not permease, yellow= pos e coli, enterovacter aerogenes, neg in proteus miracilis

glucose metabolism- MR and VP

M- gluc > pyruvic > mixed acid ferm > red = E coli

V- gluc > pyruvic > acetoin > diac KOH a-nap > red > 2,3-but = red pos enterobacter cloacae

amino acid use- ADC LDC ODC

org ability to decarb or hydroly AA, must be gluc fermenter needs acidic environment, cresol red, pos = brom purple due to pH, neg= yellow

ADC LDC ODC- enterobacter aerogenes

LDC- pos purple, ODC- pos purple

ADC LDC ODC- escherichia coli

variable

ADC LDC ODC- klebsiella pneumoniae

L- pos purple, O- neg

ADC LDC ODC- proteus vulgaris

neg all yellow

ADC LDC ODC- pseudomonas aeruginosa

A- pos purple

ADC LDC ODC- salmonella Typhi

L- pos purple, delayed pos purp

ADC LDC ODC- serratia marcesens

L and O- pos purple

ADC LDC ODC- shigella flexneri

A- delayed pos or neg

ADC LDC ODC- vibrio cholerae

A and O- pos purple

AA use- PAD

detects phenyl deasmin, green= proteus, morganella, providencia

citrate utilization

determines if simmons’ citrate as sole carbon source, media- ammonium salt and bromothymol blue pH (green to blue),

citrate utilization salmonella enterica

pos= blue

citrate utilization klebsiella pneumon

pos= blue

citrate utilization E. coli

no color change neg= green growth inhib

Urease

yellow becomes pink/red is can hydrolyze urea, Proteus

nitrate and nitrite production

ability of organism to reduce rate to rite with nitroreduc, diazo red dye, red= pos, no color = neg, verify with zinc, color change after zinc= true neg, no color change after zinc= true pos

nitrate and nitrite production- e. coli

red pos, clear before and after zine= pos

nitrate and nitrite production- acinetobacter baumanni

no color= neg red after zine= true neg

gelatin liquefaction

presense of gelatinase= liquid pos gelatin liquefaction

motility

stab org into agar tube, incubate 24hrs, diffuse= pos e. coli, enterobacter, citrobacter, salmonella, serratia

e. coli ID

LF, beta or gamma, oxidation -, indole +, citrate -, PYR - on gamma

proteus sp ID

NLF, swarming, ox -, indole - = micabilis, amp S (unless maltose), indole + = vulgaris

lactose ferm pos for other tests

e coli, klebsiella sp, enterobacter sp, citrobacter sp

Klebsiella oxytoca vs Klebsiella pneumoniae

oxytoca indole +, pneumoniae indole -

non lac ferm- LDA TDA PDA pos

ONPG neg, purease + , proteus, morg morg,

non lac ferm- LDA TDA PDA neg

shigella, salmonella, serratia sp, citribacter sp, yersinia entercolitica,

GNR non gluc fermenting sp

Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Acinetobacter baumanii, Burkholderia cepacia, opportun, difficult to treat

GNR non gluc fermenting characteristic

BAP, CHOC, maybe MAC, glucose O or I, 22-35 C 24-72 hrs, aerobic, ox +

Pseudomonas aeruginosa

most common, not norm flora, wounds, burns, cystic rib, resist abx and mucoid, beta, grow on MAC, metallic, grapes or fritos, ox +, arginine +, citrate +, pyoverdin, pyocyanin, pyorubin, pyomelanin

Stenotrophomonas maltophilia

ox -, strong maltose ox, 3rd most common, BAP= pale yellow to lavender, MAC, lysine +, DNase +, abx R unless SXT

Campylobacter

helical spiral, gull wing, motile, asaccarolytic, microaerophilic, capnophilic, 37-42 C, not at 25 C, no MAC, camy CVA