Sunday, May 11 • O 075
C. Fulchiron, M. Guicherd, L. Munoz, D. Archeny, S. Ghirardi, A. Van Belkum, G. Durand
bioMérieux, R&D Microbiology, La Balme Les Grottes, France
Objectives:
The Smart Incubator System (SIS) [bioMérieux] is an automated system for the incubation and imaging of Petri dishes. The agar plates
are incubated upside down under appropriate humidity conditions with or without addition of CO2. This study reports on the ability to
incubate agar plates for 5 days within the SIS.
ORAL PRESENTATION
Validation of the Smart Incubator system (SIS)
[bioMérieux] for prolonged incubation of fastidious bacteria
Methods:
We tested a total of 65 strains of fastidious bacterial species including species from the HACEK group and from Aggregatibacter spp.,
Haemophilus spp., Pasteurella spp., Arcobacter spp., Actinobacillus spp., Streptococcus spp., Rhodococcus spp., Neisseria spp., Rothia
spp., Nocardia spp., Erysipelothrix spp., Gemella spp., Aerococcus spp., Dysgonomonas spp., Capnocytophaga spp., Abiotropha spp. The
strains were inoculated on Columbia agar + 5% sheep blood (COS) [bioMérieux] and Chocolate agar + PolyVitex™ (PVX) [bioMérieux].
Plates were inoculated in duplicate in order to create two similar lots of agar plates. The first lot was incubated in the SIS and the second
in a standard incubator. Incubation conditions were identical for the SIS and the standard incubator (i.e. 37°C, 5% of CO2 and 90% of
relative humidity). We compared bacterial growth in the SIS versus the standard incubator during 5 days in terms of time to positivity and
size of the colonies at day 4. In this study we tested also 50 sterile agar plates (25 COS and 25 PVX) that were incubated during 5 days
in the SIS in order to assess the agar integrity in terms of moisture and color.
Results:
The time to culture positivity for all 65 strains was within 24 hours for both the SIS and the standard incubator. The colony sizes of the
65 strains measured after 4 days of incubation was not significantly different between plates incubated in the SIS and plates incubated
in the standard incubator. The minimum colony size was 0.40 mm for a strain of Eikenella corrodens on COS media ; the maximum
measured colony size was 6 mm for a strain of Kingella kingae on both COS and PVX media. No significant loss of moisture or agar damage
(e.g. macroscopic cracks) were observed for all 50 sterile plates. No color change was observed for PVX agar plates but a slight darkening
of the COS agar plates was noticeable after the first day of incubation, independent of the incubator type, due to the CO2 atmosphere.
Conclusions:
The study demonstrates that the SIS ensures perfect growth of colonies for fastidious bacteria, which is equivalent to the growth obtained
in a standard incubator. The incubation conditions of the SIS preserve the integrity of the agar and ensure humidity levels. In conclusion,
the SIS enables and facilitates extended incubation of agar plates up to 5 days and therefore proves useful for culturing clinical samples
containing fastidious bacteria.
13