Research / Collections / CRBIP / General informations concerning the collections / X - Frequently Asked Questions (F.A.Q)

X - Frequently Asked Questions  (FAQ)

What is the role of a biological resource centre?

A Biological Resource Centre holds collections of biological material and the information associated with them, to facilitate access to this material for sustainable use.

What are the interests of a Biological Resource centre?

• They increase the number of microbial strains available to the scientific community and to industry and they preserve biodiversity
• Their management follows the principle of quality assurance, maximising traceability at all levels
• They distribute biological resources in accordance with the legislation in force
• They distribute information about strains

What is the difference between a biological resource centre and a collection?

Biological Resource Centres may contain several collections or parts of collections.  They operate according to the principles of quality assurance and are responsible for the distribution of the resources they hold and/of the in²formation associated with them.

What is the difference between the CIP and the other collections of the CRBIP?

The CIP contains a large number of bacterial strains from very different species (more than 4068 species) and bacterial strains of interest to teaching institutions and laboratories. The other bacterial collections are more "specialized" and contain many strains from the same species, facilitating studies of epidemics, for example. CRBIP also gathers fungi, virus… etc..

What is a type strain?

A type strain is a strain that defines a species and is representative of that species (there is only one type strain per species. Type strains are identified by the letter "T" following their registration number. Information concerning bacterial nomenclature and taxonomy is available from:
http://www.bacterio.cict.fr/bacdico/genomospecies.html

What is bacterial nomenclature?

All information concerning bacterial nomenclature is available from :
http://www.bacterio.cict.fr/bacdico/systematique/nomenclature.html

Can I use a medium other than that recommended in the catalogue?

In most cases, the bacteria can grow in different medium. However, the medium recommended in the catalogue gives the best growth and is generally the medium that the scientist depositing the strain recommended for maintaining the phenotypic and genotypic properties of the strain.

Can I make subculture from the sample I receive?

Repeated transfers of bacterial cultures may lead to contamination or to spontaneous mutation affecting biochemical markers and antibiotic susceptibility/resistance profiles. In any case, it is recommended to aliquot subcultures.

What are the main reasons for a failure of strains to grow in culture?

Strains may fail to grow in culture due to: 

• Not all the sample in the ampoule being used.
• Too hot a pipette being used to break open the ampoule.
• Use of a medium other than that specified in the catalogue.
• Too short an incubation time or an inappropriate culture temperature and/or atmosphere.
• Innoculation of too large a volume of medium.

What is the best method for preserving bacterial cultures?

Storage in liquid nitrogen is clearly the best method for long-term preservation, including  mutant and carrying plasmid strains.
Freeze-drying is the best method for the worldwide distribution of samples, .

Why are some bacterial strains supplied in flasks and others in sealed ampoules?

The bacteria packaged in flasks are generally those produced in large numbers due to high demand. These strains are generally strains recommended for controls or for teaching purposes.

Is there an expiry date for using the freeze-dried ampoule?

No, there is no limit to the vacuum shelf life.
Storage conditions are vital: constant low temperature, away from light and with a strong vacuum in the ampoule. Atmospheric humidity is enough to damage the lyophilisate if the vacuum is broken. We test for a vacuum before dispatching all freeze-dried strains.

I am a scientist: what do I have to do to deposit a strain in the CRBIP?

Details of the procedure to follow are available here

Do freeze-dried ampoules contain a fixed number of bacteria?

No, the number of CFU/ml in freeze-dried ampoule is not known.

Any comments or questions, write to

crbip@pasteur.fr