ABSTRACT
Transposon-induced B. pseudomallei mutants deficient in membrane proteins production were obtained for evaluation of the functional role of these cell components. In comparison with the wild type strain B. pseudomallei 57576, mutant clones TTM6, TTM7 and TTM9 carrying Tn5 chromosome insertions were characterized by lost or decreased production of outer membrane proteins 27, 48, 52, 150, 200 kDa. Alterations in outer membrane protein spectra were accompanied by twofold increase in susceptibility of bacteria to fluoroquinolones (pefloxacin, ofloxacin) and cephalosporins (ceftazidime) and noticeable reduction of virulence for white mice and guinea pigs in contrast to the initial strain, the obtained mutants were also less resistant in in vitro phagocyte killing.
Subject(s)
Burkholderia pseudomallei/genetics , Burkholderia pseudomallei/metabolism , DNA Transposable Elements , Membrane Proteins/biosynthesis , Mutation , Animals , Anti-Bacterial Agents/pharmacology , Bacterial Outer Membrane Proteins/drug effects , Bacterial Outer Membrane Proteins/genetics , Bacterial Outer Membrane Proteins/metabolism , Burkholderia pseudomallei/drug effects , Burkholderia pseudomallei/pathogenicity , Ceftazidime/pharmacology , Chromosomes, Bacterial , Drug Resistance, Bacterial/genetics , Guinea Pigs , Melioidosis/microbiology , Membrane Proteins/genetics , Mice , Ofloxacin/pharmacology , Pefloxacin/pharmacology , Virulence/geneticsABSTRACT
Criteria for the evaluation of the plasmocoagulase activity of natural isolates and mutant strains of the causative agents of glanders and melioidosis were worked out, which made it possible to subdivide them by this sign into pathogens with high, moderate and low activity. Plasmocoagulase produced by pathogenic Burkholderia was shown to be a thermolabile enzyme, comparatively stable with respect to the action of such chemico-biological agents as hydrogen peroxide and chloramine.
Subject(s)
Burkholderia mallei/enzymology , Burkholderia pseudomallei/enzymology , Coagulase/metabolism , Glanders/microbiology , Melioidosis/microbiology , Animals , Burkholderia mallei/pathogenicity , Burkholderia pseudomallei/pathogenicity , Chloramines/pharmacology , Enzyme Stability , Glanders/blood , Humans , Hydrogen Peroxide/pharmacology , Melioidosis/blood , Substrate Specificity , VirulenceABSTRACT
Burkholderia pseudomallei-like microorganisms have been isolated from soil and water in regions with endemic melioidosis. These strains have biochemical and antigenic profiles identical to melioidosis agents, except that they differ by virulence and L-arabinose (vir-, ara+). There are minor differences between these species by rRNA sequence. DNA hybridization and, more so, positive transformation of DNA auxotrophic mutants of B. pseudomallei by cell lysates of B. thailandensis and B. mallei confirmed the homology of these species' genomes. These members of the Burkholderia genus (pseudomallei, mallei, and thailandensis) can be regarded as a supraspecies taxon: pseudomallei group. B. thailandensis strains are not virulent for guinea pigs and slightly virulent for golden hamsters. Immunization with live cultures of B. thailandensis protected more than 50% guinea pigs challenged with 200 LD50 B. pseudomallei 100. B. thailandensis is suggested as a potential melioidosis vaccine.
