Appearance of Enterobacteriaceae
on Selected Media
Clinical Microbiology Review 186
ORGANISM TSI MacCONKEY HEKTOEN ENTERIC XLD
Escherichia coli
Shigella
Edwardsiella
Citrobacter
Salmonella
Klebsiella
Enterobacter
Serratia
Proteus
Morganella
Providencia
Yersinia
Yellow
Colorless
Red, yellow, or colorless with
or without black centers
Red, yellow, or colorless with
or without black centers
Red with black center
Yellow
Yellow
Yellow or colorless
Yellow or colorless, with or
without black centers
Red or colorless
Yellow or colorless
Yellow or colorless
A/A, gas
K/A
K/A, gas, H 2 S
A/A or K/A, gas, with
or without H 2 S
K/A, gas, H 2 S
A/A, gas
A/A, gas
K/A
K/A (mirabilis) A/A
(vulgaris), gas, H 2 S
K/A, gas
K/A
Yellow/orange
Flat, dry pink colony with darker pink halo
Colorless
Colorless
Colorless at 24 hr. May become pink
at 48 hr
Colorless
Pink, mucoid
Pink. May be mucoid
Colorless at first, turning pink. S. marcescens
may have red pigment at RT
Colorless. May swarm
Colorless
Colorless
Colorless to peach
Yellow
Green
Colorless
Colorless
Green
Yellow
Yellow
Colorless
Colorless
Colorless
Colorless
Salmon
