[Comparative characteristic of Burkholderiae pseudomallei group].

AIM: Comparative characteristic of diagnostic value of main cultural-biological characteristics of Burkholderiae pseudomallei group. MATERIALS AND METHODS: 59 strains of B. pseudomallei, 14 --B. mallei and 5--B. thailandensis were used in the study. Biochemical characteristics were studied by generally accepted methods, antigenic properties were evaluated in agglutination reaction and immunoelectrophoresis, virulence was determined by Dlm for laboratory animals, antibiotic sensitivity was verified by disc-diffusion method. RESULTS: Passaging of B. pseudomallei and B. mallei in mice results in increase of virulence, preservation of initial sensitivity to antibiotics, contraction of precipitogen specter. During therapy of experimental melioidosis in guinea pigs resistance to chemopreparations of various groups is formed. Varying degree of virulence and sensitivity to antibiotics of various B. thailandensis strains was established. Dependence of sensitivity on in vitro cultivation was not detected. CONCLUSION: Stability of diagnostically significant tests used for identification of Burkholderiae pseudomallei group was established. Relevance of attribute set expansion that facilitates their differentiation is justified.

[Experimental study on chemotherapy of acute glanders].

Glanders is a zoonotic infection inducing acute forms of the disease (pneumonia, sepsis) in humans and animals under certain conditions, which even with the use of modern chemotherapy have unfavourable prognosis. Insufficient of efficacy of antibiotics with in vitro low MIC for planktonic bacterial suspension of Burkholderia mallei in chemotherapy of acute forms of glanders was due to the capacity of the pathogen for intracellular survival and formation of biofilms. Under such conditions the susceptibility of B. mallei to antibiotics lowered by several orders of magnitude. Chemotherapy of the glanders acute forms in animals usually provided only an increase of the lifespan, while among the survivors there was recorded a high relapse rate. More favourable outcomes were observed with the use of in vitro effective antibiotics in the form of clathrate compounds or especially liposomal forms. In the experiments with golden hamsters the survival rate reached 100% in 1000 Dlm infection even with the treatment onset by meropenem liposomal form 48 hours after the infection. Chemotherapeutics in the liposomal form significantly lowered resistance of B. mallei in both the experiments with a suspension of planktonic organisms and the use of bacteria interned in eukaryotic cells (Tetrahymena pyriformis).

[In vitro antibiotic susceptibility compliance with efficacy of chemotherapy in infections due to pathogenic Burkholderias].

Among the known species of Burkholderia only two are obligate pathogens, i.e., B. mallei and B. pseudomallei, causative agents of glanders and melioidosis respectively. The other species are saprophytes as natural inhabitants of water reservoirs and soil, still capable of causing opportunistic infections in humans and animals under definite conditions. All the species of Burkholderia are characterized by high resistance to antibacterials, including antibiotics. By the MICs, the most efficient chemotherapeutics against pathogenic burkholderias are tetracyclines, fluoroquinolones, penems and combined sulfanilamides. In the treatment of experimental glanders and melioidosis the set of the effective drugs had the inverse variation dependence on the infection severity and the desease process rate. Co-trimoxasole showed the best results, then followed doxicycline, ciprofioxacin and ceftazidime in the diminishing succession. The modification of the method for determination of antibiotic susceptibility with addition of native blood to the medium and the subculture under the atmosphere of 5% CO2 was shown useful in estimation of the prospects of the use of chemotherapeutics for the treatment of Burkholderia infections.