Quantitative method for the determination of antibiotic-resistant gut bacterial strains for the early diagnosis of chronic arthritis.

Based on the clinical and microbiological monitoring of two groups of children aged 3 to 17 years with acute (n=78) and chronic (n=46) course of reactive arthritis (ReA), a method for early diagnosis of chronic arthritis was developed by determining the number of antibiotic-resistant coprostrains in patients with ReA, characterized by the absence of the need to isolate a pure culture of the pathogen and its identification; inoculation of faeces at a dilution of 10-5 on solid 1.5% GRM-agar with an antibacterial agents used in the treatment of a particular patient, at a minimum inhibitory concentration in the resistance range, followed by incubation and counting of the colonies of microorganisms grown on the plate. A significant relationship between the number of antibiotic-resistant gut bacterial strains and the course of arthritis (acute, chronic) was revealed, and the borderline value of the number of antibiotic-resistant gut bacterial strains was determined - 5×103 CFU/g, which allows differentiating the acute course from the chronic one: in the acute course< 5×103 CFU/g, with chronic - ≥ 5×103 CFU/g. The method allows, at the stage of completion of anti-inflammatory therapy in the active phase of the disease, to identify a risk group for the development of a chronic course of arthritis among patients with ReA, which can contribute to timely therapeutic measures aimed at preventing recurrence of the disease and making the patient disabled.