blaTEM map

The Dynamics of blaTEM Resistance Gene in Salmonella Typhi

Presentation from the Research Group for Genomic Epidemiology – 18 September 2023

Salmonella Typhi (S. Typhi) remains an important pathogen causing typhoid fever. Despite that the number of cases worldwide have been decreasing, it is still a public health concern. Antimicrobial resistance (AMR) is a major threat to human and animal health. Several studies reported about multi-drug resistance (MDR) and extended-spectrum drug resistance (XDR) S. Typhi isolates. One of the important AMR mechanisms in S. Typhi is production of TEM b-lactamase expressing from blaTEM gene. There is limited knowledge on the dynamics blaTEM in S. Typhi populations. Hence, this study aimed to 1) investigate dynamics of blaTEM gene in S. Typhi through flanking gene profiles and 2) to find association of the profiles with sample metadata and analyzed genomic data.

Our study methods were divided into 3 main processes: 1) downloading and cleaning publicly available metadata from ENA / NCBI 2) analyzing whole genome sequencing data with bioinformatic tools using KmerFinder, SISTR, ABricate, MGE, Flankophile and CSIPhylogeny and 3) visualizing the results using Microreact, Flankophile and Tanglegram.

Four main flanking gene profiles were found: 1) tnpR, blaTEM-1B, hns 2) tnpR, blaTEM-1B, aph(6)-Id, aph(3'')-Ib 3) tnpR, blaTEM-1B, sul2 and 4) tnpR, blaTEM-1B, tetR. The profiles were restricted following countries and years including associated with genotypes and antibiotic resistance gene (ARG) profiles. Additionally, we indicated that transferring of blaTEM were more expanded in the same flanking gene profile. We also illustrated upstream and downstream mobile genetic elements (MGEs) flanking the blaTEM-1B gene, Tn2, ISEc63, ISEcp1, ISVsa5 and IS5075. The study increases the understanding of dynamics of blaTEM gene and supports epidemiological studies and surveillance in S. Typhi.

Narong Nuanmuang’s presentation