Please select your topic of interest:

  • How can I avoid failure when working with my phage and under what conditions is my complaint justified, when can I claim the viability of a phage?

    We recommend only one particular strain as the host for each of our phages. Please, use only this strain as mentioned in the phage entry and use the growth conditions that we recommend for this strain in the strain entry. Please, visit our phage online information and methodology. Host culture and agar plates must always be fresh for working with a phage. Each phage suspension batch is routinely titer-controlled and each vacuum-drying production batch is viability-controlled. Complaints relating to viability of our phages in principle are not justified. A leaking receptacle containing a phage suspension or a broken glass ampoule is a justified reason for a complaint or if an ampoule does not contain filter discs. If a phage is not lysing at all in the recipient’s laboratory, it can be streaked like a microorganism with an inoculation loop on the top agar containing its host strain to get single phage plaques for further propagation.

  • What do phages always need for adsorption to the host bacterium?

    Addition of 1-5 mM MgSO4 and/or CaCl2 is maybe recommended for some phages. Avoid fast shaking or strong agitation of phages in liquids. Leaving phage and host for 5-10 minutes after infection without any agitation enhances adsorption.

  • Can phage suspensions be stored in the refrigerator?

    Most phages store well in the refrigerator unfrozen for some weeks or longer but DSMZ generally recommends immediate use, see Terms and Conditions. Do not freeze phages without adding a cryoprotectant, e. g. 10% glycerol.

  • What is the difference between dried bacterial strains and filter-dried phages?

    Bacterial cell suspensions are dried together with a protectant and a pellet forms that can be rehydrated for initial revitalisation, phages are dried as suspensions on filter paper strips and require their host strain for initial propagation, please see instructions given here.