Abstract:
Objective To compare the genomic characteristics of Burkholderia pseudomallei isolates from four recurrent melioidosis cases in Sanya, Hainan during 2012-2023, and investigates the characteristics of recurrent case types and strain evolutionary dynamics.
Methods Eight strains of B. pseudomallei isolated from four patients with recurrent melioidosis were used in this study. Whole genome sequencing and assembly were performed for these isolates. Appropriate software, website or database were used for genomic mapping, single nucleotide polymorphism (SNP) detection, multilocus sequence typing, proteomic difference analysis, virulence factor and drug resistance gene identifications, and antimicrobial susceptibility testing in vitro.
Results The genotyping of the four groups of B. pseudomallei isolates remained consistent, with annual average SNP changes of 23.24, 69.01, 77.59, and 18.80 SNPs per genome per year, respectively. Each group of the isolates shared highly similar proteomes and virulence gene profiles. Notably, the number of unique protein clusters in each strain did not exceed one, and the differed virulence genes ranged from 1 to 4. Furthermore, no alterations were detected in antimicrobial resistance genes or in vitro antimicrobial susceptibility tests.
Conclusion It is highly probable that the recurrences of melioidosis all in the four patients were caused by the initial strain. The characteristics of isolate variations might be associated with the adaptability of the isolates within the hosts.