Whole Genome Sequencing and Comparative Genomics of the Emerging Pathogen Burkholderia pseudomallei Isolated from Two Travel-Related Infections in Hungary.

BACKGROUND

Burkholderia pseudomallei, the causative agent of melioidosis, is a neglected tropical pathogen that has been increasingly encountered in Europe through travel-related infections. Clinical manifestations range from localized abscesses to life-threatening sepsis, posing diagnostic challenges in non-endemic regions.

METHODS

We report two travel-associated melioidosis cases confirmed in Hungary between 2008 and 2024. Whole-genome sequencing (WGS), multilocus sequence typing (MLST), and core-genome MLST (cgMLST) were performed for molecular characterization. In parallel, a systematic review of travel-related melioidosis cases reported in Europe (1980-2025) was conducted according to PRISMA 2020 guidelines. Data were retrieved from PubMed, Scopus, Google Scholar, and the PubMLST database.

RESULTS

In silico MLST identified two distinct sequence types (STs): a novel ST1643, and ST1051, previously reported in Asia and Australia. Both isolates clustered within the Asian clade, confirming an imported origin. Virulence profiling revealed major determinants, including the Yersinia-like fimbriae (YLF) cluster, fhaB3, and ITS type C. The ST1643 isolate carried the bimABm variant and multiple resistance genes (blaOXA-57, blaPenI, and amrAB efflux system), while ST1051 harbored blaOXA-59. The literature review identified 82 studies encompassing 195 European cases, most originating from Southeast Asia, with pneumonia, followed by septic form and abscess as the predominant presentation. We found only eight neuromelioidosis cases in Europe.

CONCLUSIONS

This study represents the first report of neuromelioidosis in Hungary, and the first global description of ST1643. Combined genomic and epidemiological data highlight the need for improved clinical awareness, genomic surveillance, and diagnostic preparedness in non-endemic regions, as global travel and climate change expand the distribution of melioidosis.