The procedure for taking material and carrying out a bacteriological examination for diphtheria

June 21, 2018 22:30 | Diagnostics
The material must be taken from the throat and nose with separate tampons. When the material is delivered to the laboratory in less than 2 hours after collection, dry tampons can be used, with a longer delivery time, the material is taken with swabs moistened with 5% glycerol solution or a dry swab, which is then immersed in the enrichment medium. The interval between eating and taking the material should not be less than 2 hours. If the patient received antibiotics, the study is carried out 3 days after the end of their intake. The material must be taken from the pharynx, without touching the mucous membrane of the oral cavity.

If there are films, the material is taken at the border of healthy and diseased tissue.

All persons with a nasal part of the pharynx for the purpose of differential diagnosis with diphtheria, as well as healthy faces from the foci are subject to examination to determine the prevalence of carriage.

When receiving dry tampons, an immediate seeding is carried out on a Petri dish with Clauberg II medium, blood tellurite agar, Buchin medium, cystine-tellurite-serum medium. The storage medium is put on 18-20 hrs in a thermostat, then the tampon is wrung out against the walls of the tube, removed, and with medium the loop is inoculated on one of the solid nutrient media using 1/2 or 1/4 Petri dishes for each analysis.


On day 2, in the presence of typical colonies, smears are made and culture is planted on a medium to determine toxigenic properties, into a medium for the detection of cystinase, into a Leffler slant test tube, to Hiss's medium with sucrose and glucose, and to starch. A preliminary answer can be given.

On the third day, a bacterioscopy is performed. It should be remembered that the morphology of diphtheria rods grown on solid nutrient media differs somewhat from the morphology of rods grown on liquid nutrient media( the sticks are shortened and the granularity is poorly expressed).If there are typical sticks, a final answer can be given.

Information on toxicity is given when precipitation lines appear. When receiving material from patients, it is possible to perform direct smear-positive bacterioscopy from a swab.