Evidence map›Paper›PMID 40627640›Full record

ArticlePLoS neglected tropical diseases2025

Determining genotype and antimicrobial resistance of Salmonella Typhi in environmental samples by amplicon sequencing.

Catherine Troman, Samuel T Horsfield, Dilip Abraham, Venkata Raghava Mohan, Sidhartha Giri, Satheesh Nair, Alexander G Shaw, Zoe Dyson, Kathryn E Holt, Nicholas C Grassly

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Article in PLoS neglected tropical diseases, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

10 authors.

Catherine TromanDepartment of Infectious Disease Epidemiology & MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom.ORCID 0000-0001-8584-7785
Samuel T HorsfieldDepartment of Infectious Disease Epidemiology & MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom.
Dilip AbrahamChristian Medical College, Vellore, India.
Venkata Raghava MohanChristian Medical College, Vellore, India.
Sidhartha GiriChristian Medical College, Vellore, India.
Satheesh NairGastrointestinal Bacteria Reference Unit, UK Health Security Agency, London, United Kingdom.
Alexander G ShawDepartment of Infectious Disease Epidemiology & MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom.
Zoe DysonDepartment of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
Kathryn E HoltDepartment of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
Nicholas C GrasslyDepartment of Infectious Disease Epidemiology & MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom.

Funding

Gates Foundation INV-002381Medical Research Council (MRC) MR/X020258/1
6 · The paper itself

Abstract

backgroundEstimates of the burden of typhoid fever due to Salmonella enterica serovar Typhi (S. Typhi) rely on data from clinical surveillance, which is rarely done in low income settings and is also limited by the poor sensitivity of the assays used and the reliance on health seeking by patients. Environmental surveillance for S. Typhi shed by symptomatic and asymptomatic individuals in wastewater offers a sensitive surveillance tool that could help to inform burden estimates. Sequencing S. Typhi direct from wastewater concentrates has the potential to identify circulating genotypes and associated antimicrobial resistance (AMR) genes, supporting public health interventions such as vaccination and antimicrobial usage. METHODOLOGY AND PRINCIPAL

findingsWe designed a multiplex targeted amplicon sequencing protocol for genotyping and determining AMR in S. Typhi from wastewater samples, targeting SNPs that identify genotypes of interest and both chromosomal and plasmid-borne AMR. PCR products were sequenced using the Oxford Nanopore Technologies (ONT) MinION, and genotypes and AMR identified using the GenoTyphi program. We tested this approach on samples from south India from both hospital outflow and wastewater collected from the community. All samples tested were suspected to be positive for S. Typhi following quantitative PCR for ttr, tviB, and staG gene targets. Out of 110 samples tested we were able to determine a genotype and/or AMR for 8. All samples that gave a genotype call suggested a genotype consistent with those found in clinical cases in India during the same time period and produced consensus sequences that clustered with S. Typhi when included in a phylogenetic tree.

conclusionsIn this study, we provide proof of concept data for amplicon sequencing of S. Typhi in wastewater which with further optimisation could be used to complement clinical surveillance data or provide data on S. Typhi presence in the absence of clinical surveillance. This information can inform public health interventions, and the concept could be applied to other pathogens of interest for genotyping from environmental surveillance samples.

Indexed as

Anti-Bacterial AgentsDrug Resistance, BacterialGenotypeSalmonella typhiWastewaterHumansIndiaMicrobial Sensitivity TestsPolymorphism, Single NucleotideSequence Analysis, DNATyphoid FeverAnti-Bacterial AgentsWastewater

Identifiers

PMID40627640
PMCPMC12237024

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