Effectiveness of using liquid transport media in bacteriological diagnostics of diphtheria infection

The results of evaluating the effectiveness of the use of liquid transport media at the preanalytical stage of bacteriological diagnosis of diphtheria infection are presented. A typical toxigenic strain of C. diphtheriae biovar gravis № 665 was used. The experiments were carried out using a laboratory-prepared medium based on GRM-broth (State research center for applied biotechnology and microbiology, Obolensk), a transport system with a fleecy probe swab (DELTALAB) and a transport system ∑-Transwab ® with a polyurethane Sigma-swab (Medical Wire & Equipment Co. (Bath) Ltd.). The tampons were pooled with a 24-hour bacterial culture of C. diphtheriae, then immediately seeded on Tellurite-containing blood agar. Storage conditions were simulated for 6-24 hours: at room conditions +(20-25)° C, in the refrigerator +(4-8)° C, in a thermostat +(37±1)° C. Storage of C. diphtheriae was most optimal on two liquid transport systems in a refrigerator +(4-8)° C for 6 and 24 hours; in room conditions +(20-25)° C - there was a decrease in seeding after 6 hours and loss of pathological material after 24 hours, more pronounced on a fleecy probe swab; under thermostat conditions +(37±1)° C on both transport systems, a decrease in seeding was noted after 6 hours and a complete loss of pathological material after 24 hours. The results obtained demonstrated the efficiency of using the Amies liquid transport medium and justify the need to develop a domestic analogue of the transport system based on the Amies liquid medium for the bacteriological diagnosis of diphtheria infection.