IDENTIFICATION AND CHARACTERIZATION OF A 2-COMPONENT REGULATORY SYSTEM INVOLVED IN INVASION OF EUKARYOTIC CELLS AND HEAVY-METAL RESISTANCE IN BURKHOLDERIA-PSEUDOMALLEI
Al. Jones et al., IDENTIFICATION AND CHARACTERIZATION OF A 2-COMPONENT REGULATORY SYSTEM INVOLVED IN INVASION OF EUKARYOTIC CELLS AND HEAVY-METAL RESISTANCE IN BURKHOLDERIA-PSEUDOMALLEI, Infection and immunity, 65(12), 1997, pp. 4972-4977
Burkholderia pseudomallei is the causative agent of melioidosis, a dis
ease increasingly recognized as an important cause of morbidity and mo
rtality in many regions of the world, B. pseudomallei is a facultative
intracellular pathogen capable of invading eukaryotic cells, We used
Tn5-OT182 mutagenesis to generate mutants deficient in the ability to
invade a human type II pneumocyte cell line (A549 cells), One of these
mutants, AJ1D8, exhibited approximately 10% of the ability of the par
ental strain, 1026b, to invade A549 cells. There was no difference in
the abilities of 1026b and AJ1D8 to resist killing by RAW macrophages
or the human defensin HNP-1, The nucleotide sequence flanking the Tn5-
OT182 integration in AJ1D8 was determined, and two open reading frames
were identified, The predicted proteins shared considerable homology
with two-component regulatory systems involved in the regulation of he
avy-metal resistance in other organisms. AJ1D8 was 16-fold more sensit
ive to Cd2+ and twofold more sensitive to Zn2+ than was 1026b but was
not sensitive to any of the other heavy metals examined, The B. pseudo
mallei two-component regulatory system, termed irlRS, complemented the
invasion-deficient and heavy-metal-sensitive phenotype of AJ1D8 in tr
ans, There was no significant difference between the virulence of AJ1D
8 and that of 1026b in infant diabetic rats and Syrian hamsters, sugge
sting that the irlRS locus is probably not a virulence determinant in
these animal models of acute B. pseudomallei infection.