Background:
Introduction. Infections following a kidney transplantation can have exogenous and endogenous origin. The course of infection and prognosis are influenced by the type of microorganism and its drug-resistance profile. According to the current consensus, the dose and type of immunosuppressants modify the patient’s immunological response, and increase the risk of opportunistic infections. At present, little is known about how a variety of immunosuppressive therapies may potentially affect the microbiological status of the oral cavity.

Aim:
Aim of the study. To analyse drug resistance of isolated bacteria and to assess the impact of immunosuppression on the species composition in the examined locations of dentures and the pharynx.

Material and methods:
The material consisted of 278 clinical samples collected from denture wearers ( both from the pharyngeal mucosa and the denture plate). Samples were collected from 57 kidney recipients (the study group) and 27 generally healthy individuals (the control group). Within the study group, 28 patients were identified, in whom swabs were taken three times in the period of 0-12 months postoperatively. The isolated strains were identified and their drug resistance determined. The results were subjected to statistical analysis.

Results:
In the study group, bacteria isolated in the pharyngeal samples had multi-drug resistance (MDR) of 45.4%; among the controls, the corresponding percentage was only 16.16%. The number of MDR strains of S. epidermidis rose significantly at one year after transplantation. The summary increase in dosage of mycophenolate mofetil and azathioptine was associated with the growth in bacterial isolation.

Conclusions:
In the period of one year after the kidney transplantation procedure, Staphylococcal population structure underwent variations in the oral cavity and on the denture plates, which may be due to the type and dosage regimen of immunosuppressive drugs. Increased bacterial drug resistance, especially concerning S. epidermidis, may adversely affect therapeutic options of potential infections in this group of patients.