chapter 19: enterobacterales

enterobacterales

gram stain:

colony:

ferment:

oxidase:
nitrate to nitrite:

gram stain: gram neg rods, coccobacilli/straight rods

colony: large, gray, wet colonies

ferment: gluose fermenter

oxidase: most are - (+ plesiomonas shigelloides)
nitrate to nitrite: +

enteric habitats

soil, water, sewage, plants, GI

enteric normal flora

e. coli

citrobacter sp

enterobacter sp

klebsiella sp

morganella sp

proteus sp

not normal flora

salmonella typhi

shigella

yersinia entercolitica

plesiomonas shigelloides

serratia sp

enteric clinical significance

mostly intestinal

wound infections

pneumonia

meningitis

uti

bacteremia

enterobacterales two major groups

lactose fermenters

non-lactose fermenters

lactose fermenters 2 enzymes

beta-galactoside permease

beta-galactosidase

lactose fermenters genus/sp

e. coli

enterobacter sp

klebsiella sp

citrobacter (+/-)

serratia sp

enteric mostly motile at body temp except

klebsiella

shigella

yersinia

nonlactose fermenters

salmonella sp

shigella sp

yersinia sp

providencia sp

morganella sp

e. coli clinical significance

traveler’s diarrhea

uti, pneumonia, sepsis, meningitis, wounds/abscess

e. coli biochemical tests

ferment:

MR

VP

oxidase

hemolysis

citrate

ferment: lactose fermenter

MR +

VP =

oxidase =

hemolysis beta

citrate =

klebsiella sp

common cause of ___

virulence due to ___

common cause of pneumonia

virulence due to capsule

klebsiella biochemical tests

fermenter:

colony morphology:

motility:

citrate/urea

h2s

fermenter: lactose fermenter

colony morphology: hypermucoid

motility: nonmotile (usually)

citrate/urea: +/+

h2s =

klebsiella IMVC

IMVC = = + +

family: yersiniaceae
genus —
sp —

genus: serratia
sp: marcescens

serratia marcescens pigment

prodigiosin

serratia sp biochemical tests

ONPG

fermenter

dnase

VP

MR

ONPG +

fermenter - slow lactose

dnase +

VP +

MR =

genus: citrobacter

sp —

sp: koseri, freundii

citrobacter sp clinical significance

uti

citrobacter tests

ferment

urease

decarboxylate lysine

MR

VP

ferment - variable lactose

urease +

decarboxylate lysine =

MR +

VP =

family?
proteus sp

morganellaceae

proteus sp

indole

h2s

ferment

phenylalanine deaminase

indole +

h2s + (mostly)

ferment non-lactose

phenylalanine deaminase +

swarming on BAP

burnt chocolate odor

proteus sp

primary intestinal pathogens

salmonella sp

shigella sp

yersinia sp

salmonella sp tests

ferment

indole

phenylalanie deaminase

urease

vp

h2s

no lactose fermentation

= indole, phenylalanie deaminase, urease, vp

h2s+

enterics characteristics

gnr

oxidase neg

ferments glucose

reduce nitrate to nitrite

enteric oxidase +

plesiomonas shigelloides