[Determination of Azospirillum Brasilense Cells With Bacteriophages via Electrooptical Analysis of Microbial Suspensions].

The dependence-of changes in the electrooptical properties of Azospirillum brasilense cell suspension Sp7 during interaction with bacteriophage ΦAb-Sp7 on the number and time of interactions was studied. Incubation of cells with bacteriophage significantly changed the electrooptical signal within one minute. The selective effect of bacteriophage ΦAb on 18 strains of bacteria of the genus Azospirillum was studied: A. amazonense Ami4, A. brasilense Sp7, Cd, Sp107, Sp245, Jm6B2, Brl4, KR77, S17, S27, SR55, SR75, A. halopraeferans Au4, A. irakense KBC1, K A3, A. lipoferum Sp59b, SR65 and RG20a. We determined the limit of reliable determination of microbial cells infected with bacteriophage: - 10(4) cells/mL. The presence of foreign cell cultures of E. coli B-878 and E. coli XL-1 did not complicate the detection of A brasilense Sp7 cells with the use of bacteriophage ΦAb-Sp7. The results demonstrated that bacteriophage (ΦAb-Sp7 can be used for the detection of Azospirillum microbial cells via t electrooptical analysis of cell suspensions.

Mechanized technique for phage typing and determination of antibiograms.

A device for mechanical application of either drops of phage suspensions or antibiotic-containing tablets was developed. The device consists of a Transport Apparatus which transports petri dishes from one side of the apparatus to the other in such a way that the plate and the lid of a petri dish become entirely separated at a particular stage. Either a Phage Applicating System or an Antibiotic Tablet Dispenser can be connected to the apparatus. In this way a maximum of 27 phages of 7 antibiotic tablets per plate can be applied pneumatically.

[An automatic bacteriophage distributor (author's transl)]. / Un distributeur automatique de bactériophages.

The apparatus described in this article can distribute simultaneously 22 drops of different phage suspensions at a rate of 13,200 drops per hour, which is superior than the one obtained with the presently available apparatuses. It could eventually be attached to a Petri dish distributor.

Automation of Salmonella typhi phage typing.

Two steps in the procedure for bacteriophage typing of Salmonella typhi have been automated. The culture inoculum was applied by flooding the surface of phage agar in a 150x20 mm petri dish and removing the excess liquid with a safety pipettor. This step replaced the older method of manually preparing up to 100 individual areas for inoculation. The number of bacteria per unit area was the same with both methods, so the automated method involved no change in the technique. The second automated step involved use of a bacteriophage applicator which simultaneously dispensed 59 uniform drops of bacteriophages onto the inoculated plate. The automated procedure has reduced personnel time by about 90% with no less in sensitivity or accuracy.

Bacteriophage typing of Salmonella typhimurium by use of a mechanized technique.

A new mechanized technique for the application of drops of phages on agar plates is described. Drops of equal size are delivered by needles with the aid of filtered pressurized air. The part of the device which is in contact with phage is interchangeable as a whole.