Antibiotic resistance of Burkholderia pseudomallei isolates from Guangdong province: a molecular epidemiology study

  Objective   To study drug resistance and molecular epidemiological characteristics of Burkholderia pseudomallei (Bp) strains isolated in Guangdong province and to provide evidences for surveillance, diagnosis and treatment, and prevention of melioidosis.

  Methods   Broth microdilution method was used to determine the minimum inhibitory concentrations (MICs) of antimicrobial susceptibility for 8 Bp strains clinically isolated in Guangdong province from 2018 through 2019. Whole genome sequencing was used to identify drug-resistant genes and to conduct molecular typing and phylogenetic tree construction for the Bp strains.

  Results   All the Bp stains were sensitive to tetracycline, ceftazidime, imipenem, amoxicillin-clavulanic acid, doxycycline and sulfamethoxazole. Drug-resistance gene bla_OXA-59 was detected in 7 of the 8 strains and the drug-resistance gene bla_OXA-57 was detected in 3 strains. Multilocus sequence typing (MLST) analysis showed that the 8 strains belonged to different sequence types (ST271, ST562, ST10, ST46, ST1325, ST830, ST1774, and ST1775), and 2 of them were novel types. Whole-genome single nucleotide polymorphism (wgS-NPs) phylogenetic evolution analysis demonstrated that the 8 Bp stains belonged to different clusters and closely related to several strains isolated in different geographical regions.

  Conclusion   Burkholderia pseudostellariae stains isolated in Guangdong province were not resistant to antibacterials commonly used in clinic treatment and the genomes of the strains have high genetic diversities with rapid mutation and high probability of genome recombination.