Ser.ra' ti.a
. M.L. fem. n.
Serratia
named after Serafino Serrati, an Italian physicist.
Proteobacteria / Gammaproteobacteria / Enterobacteriales / Enterobacteriaceae / Serratia
Straight rods
, 0.5–0.8 × 0.9–2.0 µm in length, with rounded ends. Conform to the general definition of the family
Enterobacteriaceae
. Gram negative, generally
motile
, by means of peritrichous flagella.
Facultatively anaerobic. Nitrate and chlorate are reduced anaerobically. Growth factors are generally not required
. Colonies on nutrient agar are most often opaque, somewhat iridescent, and either
white, pink, or red in color
. Almost all strains can grow at temperatures between 10 and 36°C, at pH 5–9, and in the presence of 0–4% (w/v) NaCl. The catalase reaction is strongly positive.
d
‐
Glucose is fermented
through the Embden–Meyerhof pathway. The major glucose entry route involves a phosphoenolpyruvate‐dependent phosphotransferase system with both enzyme II
Glc
(glucose permease) and enzyme II
Man
(mannose permease). Glucose is also oxidized to gluconate in the presence of pyrroloquinoline quinone.
Gluconate is oxidized to 2‐ketogluconate. Acetoin is produced from pyruvate
by all species except
S. fonticola
. Fructose,
D
‐galactose, maltose,
D
‐mannitol,
D
‐mannose, ribose, and trehalose are fermented and utilized as sole carbon sources.
L
‐fucose is fermented and utilized as sole carbon source by all species except
S. fonticola
.
L
‐sorbose is not fermented or utilized as sole carbon source. All species but
S. fonticola
fail to ferment or utilize dulcitol and tagatose.
N
‐acetylglucosamine,
D
‐alanine,
L
‐alanine, citrate,
D
‐galacturonate,
D
‐glucosamine,
D
‐glucuronate, 2‐ketogluconate,
L
‐proline, putrescine,
L
‐serine are utilized as sole carbon sources by most strains. Caprate, caproate,
caprylate
, and tyrosine are
utilized
as sole carbon sources by all species except
S. fonticola
. 5‐Aminovalerate, butyrate,
m
‐coumarate, ethanolamine and tryptamine are not utilized as sole carbon sources. All species except
S. fonticola
fail to utilize 3‐phenylpropionate. All species except
S. entomophila
fail to utilize itaconate. Phenylalanine, histidine, and tryptophan deaminases and thiosulfate reductase (H
2
S from thiosulfate) are not produced.
o
‐
Nitrophenyl
‐β‐
d
‐
galactopyranoside
(ONPG) is
hydrolyzed by most strains
. Esculin is hydrolyzed by most strains except
S. proteamaculans
subsp.
quinovora
.
Extracellular enzymes
of all species except
S. fonticola
hydrolyze DNA, lipids
(tributyrin, corn oil)
and proteins
(gelatin, casein), but not starch (in four days), polygalacturonic acid, or pectin. Tween‐80 is hydrolyzed by all species except
S. odorifera
. The organisms
occur in the natural environment
(soil, water, plant surfaces) or
as opportunistic human pathogens
.
The mol
%
G
+
C of the DNA is
: 52–60.
Type species
:
Serratia marcescens
Bizio 1823, 288.