Drug resistance phenotype and molecular characteristics of a virulent Vibrio vulnificus strain isolated from a fatal case

Objective To study the drug resistance phenotype and molecular characteristics of a Vibrio vulnificus strain (2014-DJH)isolated from a fatal case. Methods The biochemical test and antibiotic susceptibility test of the isolate 2014-DJH were conducted using VITEK-2 COMPACT. PCR was performed to detect the vvhA gene, pilF gene and characterize the genotype of vcg and 16S rRNA loci, and multilocus sequence typing (MLST) was used for the molecular typing of the isolate. Results The isolate was identified as a gram-negative biotype 1 V. vulnificus strain, and it was sensitive to the most tested antibiotics, but intermediate to tobramycin. It was positive for the vvhA gene, pilF gene and identified as the vcgC-16S rRNA B genotype (CB). The MLST allele numbers of 2014-DJH were glp 5, gyrB 3, mdh 32, metG 68, purM 21, dtdS 39, lysA 115, pntA 4, pyrC 42 and tnaA 75. Conclusion The isolate 2014-DJH was identified as a new type ST strain, named ST289 with the number id-389. Its genotyping results showed that this type strain has strong pathogenicity, so it is important to strengthen the monitoring and early warning of V. vulnificus infection.