| Serratia isolation from coconut - short communication - Dr. Costin Stoica |
Morphological and biochemical properties of the strain:
The red gel has been harvested with a swab and dispersed on solid and liquid medium. Both
aerobic and anaerobic growth occured. On 5% blood agar, Mueller-Hinton and Mac Conkey
agar presented S-type, medium size, red pigmented colonies after 24 hours of incubation.
Pigment production was very low when incubated at 37 ºC and more intense at room
temperature (20 ºC). Also, more pigment produced on blood agar than on Mueller-Hinton agar.
In liquid medium, after 24h of incubation, an uniform turbidity presented; without deposit.
Gram staining show small Gram-negative rods.
Non-haemolytic, catalase positive and oxidase negative. Glucose fermented with gas
production, Indole negative, Urea negative, H2S negative, Citrate positive (weak), Motility weak
/ doubtful.
Biochemical results on API 20 E strip:
ONPG +, ADH-, LDC-, ODC-, CIT+, H2S-, URE-, TDA-, IND-, VP+, GEL+, GLU+, MAN+, INO+,
SOR-, RHA-, SAC+, MEL+, AMY+, ARA+, NO2+.
API identified strain as Serratia rubidaea 92%. With ABIS 6 software (using some tests used by
API identification and more biochemical tests not taken in consideration by API) resulted
Serratia rubidaea 89%
The red gel has been harvested with a swab and dispersed on solid and liquid medium. Both
aerobic and anaerobic growth occured. On 5% blood agar, Mueller-Hinton and Mac Conkey
agar presented S-type, medium size, red pigmented colonies after 24 hours of incubation.
Pigment production was very low when incubated at 37 ºC and more intense at room
temperature (20 ºC). Also, more pigment produced on blood agar than on Mueller-Hinton agar.
In liquid medium, after 24h of incubation, an uniform turbidity presented; without deposit.
Gram staining show small Gram-negative rods.
Non-haemolytic, catalase positive and oxidase negative. Glucose fermented with gas
production, Indole negative, Urea negative, H2S negative, Citrate positive (weak), Motility weak
/ doubtful.
Biochemical results on API 20 E strip:
ONPG +, ADH-, LDC-, ODC-, CIT+, H2S-, URE-, TDA-, IND-, VP+, GEL+, GLU+, MAN+, INO+,
SOR-, RHA-, SAC+, MEL+, AMY+, ARA+, NO2+.
API identified strain as Serratia rubidaea 92%. With ABIS 6 software (using some tests used by
API identification and more biochemical tests not taken in consideration by API) resulted
Serratia rubidaea 89%
Two bacteria have been suspected for contamination:
Erwinia and Serratia. Lab tests have been performed
for identification. Results concluded in Serratia
rubidaea contamination.
Source of contamination could not been established
(coconut disease or most probably from the opening
tools). Although it may be concluded that Serratia
rubidaea grows easily on coconut marrow.
Erwinia and Serratia. Lab tests have been performed
for identification. Results concluded in Serratia
rubidaea contamination.
Source of contamination could not been established
(coconut disease or most probably from the opening
tools). Although it may be concluded that Serratia
rubidaea grows easily on coconut marrow.
One coconut has been opened and sliced then left at room temperature. After 24 hours a
sticky red coloured gel appeared on the surface of all slices. When stored at 4ºC for 3 days,
colour intensified.
sticky red coloured gel appeared on the surface of all slices. When stored at 4ºC for 3 days,
colour intensified.
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