Clinical Burkholderia pseudomallei isolates from Queensland carry diverse bimABm genes that are associated with central nervous system disease and are phylogenomically distinct from other Australian strains

Burkholderia pseudomallei is an environmental gram-negative bacterium that causes the disease melioidosis and is endemic in many countries of the Asia-Pacific region. In Australia, the mortality rate remains high at approximately 10%. The bacterium is almost exclusively found in the endemic region, which spans the Northern Territory, Western Australia and North Queensland. However, Queensland infections remain understudied compared to those of the Northern Territory. This pilot study aimed to assess the prevalence of central nervous system disease associated variant bimABm, identify circulating antimicrobial resistance mutations and genetically distinct strains from Queensland, via comparative genomics. From 76 clinical isolates, we identified the bimABm variant in 20 (26.3%) isolates and in 9 (45%) of the isolates with documented central nervous system infection (n=18). Explorative analysis suggests a significant association between isolates carrying the bimABm variant and central nervous system disease (OR 2.8, 95% CI 1.3-6.0, P=0.009) compared with isolates carrying the wildtype bimABp, with the possibility of additional driving factors. Furthermore, 50% of isolates were identified as novel multi-locus sequence types (STs), while the bimABm variant was more commonly identified in isolates with novel sequence STs, compared to those of previously described STs. Additionally, mutations associated with acquired antimicrobial resistance were only identified in 14.5% of all genomes. The findings of this research have provided clinically relevant genomic data of B. pseudomallei in Queensland and suggest that the bimABm variant may enable risk stratification for the development CNS complications and be a potential therapeutic target.