Molecular epidemiology of Burkholderia pseudomallei in Hainan Province of China based on O-antigen

Background

Burkholderia pseudomallei is a gram-negative bacterium widely found in Southeast Asia and northern Australia. This bacterium, which lacks an available vaccine, is the causative agent of melioidosis and has properties that potentially enable its exploitation as a bioweapon.

Methods

Polymerase chain reaction assays targeting each of the lipopolysaccharide (LPS) genetic types were used to investigate genotype frequencies in B. pseudomallei populations. Silver staining, gas chromatography-mass spectrometry (GC-MS), and immunofluorescence were used to characterize LPS.

Results

In our study, a total of 169 clinical B. pseudomallei isolates were collected from Hainan Province, China between 2004 and 2016. The results showed that LPS genotype A was the predominant type, comprising 91.1% of the samples, compared with only 8.9% of LPS genotype B. The majority of patients were male and were diagnosed with sepsis or pneumonia. Silver staining and GC-MS demonstrated that LPS genotypes A and B exhibited distinct phenotypes and molecular structures. Immunofluorescence tests showed there was no cross-reaction between LPS genotypes A and B.

Conclusions

This is the first report on the molecular epidemiology of B. pseudomallei based on O-antigen in China. Tracking the regional distribution of different LPS genotypes offers significant insights relevant to the development and administration of LPS-based vaccines.