Phylogenetic Analysis Indicates a Longer Term Presence of the Globally Distributed H58 Haplotype of Salmonella Typhi in Southern India. (31st January 2020)

• Record Type: Journal Article
• Authors: Pragasam, Agila Kumari; Pickard, Derek; Wong, Vanessa; Dougan, Gordon; Kang, Gagandeep; Thompson, Andrew; John, Jacob; Balaji, Veeraraghavan; Mutreja, Ankur
• Is Part Of: Clinical infectious diseases. Volume 71:Number 8(2020)
• Page Start: 1856
• Page End: 1863
• Publication Date: 2020-01-31
• Subjects: typhoid; H58 -- Salmonella Typhi -- AMR -- India; Communicable diseases -- Periodicals; 616.905
• DOI: 10.1093/cid/ciz1112
• Languages: English
• ISSNs: 1058-4838

Abstract

Abstract: Background: Typhoid fever caused by Salmonella Typhi is a major public health concern in low-/middle-income countries. A recent study of 1900 global S . Typhi indicated that South Asia might be the site of the original emergence of the most successful and hypervirulent clone belonging to the 4.3.1 genotype. However, this study had limited samples from India. Methods: We analyzed 194 clinical S . Typhi, temporal representatives from those isolated from blood and bone marrow cultures in southern India, over 26 years (1991–2016). Antimicrobial resistance (AMR) testing was performed for most common clinical agents. Whole-genome sequencing and SNP-level analysis was conducted. Comparative genomics of Vellore isolates was performed to infer transmission and AMR events. Results: We identified multidrug-resistance (MDR)–associated clade 4.3.1 as the dominant genotype. We detected 4.3.1 S . Typhi as early as 1991, the earliest to be reported form India, and the majority were fluoroquinolone resistant and not MDR. MDR was not detected at all in other genotypes circulating in Vellore. Comparison with global S . Typhi showed 2 Vellore subgroups (I and II) that were phylogenetically highly related to previously described South Asia (subgroup I, II) and Southeast Asia (subgroup II) clades. Conclusions: 4.3.1 S . Typhi has dominated in Vellore for 2 decades. Our study would assist public health agencies in better tracking of transmission and persistence of this successful clade in India and globally. It informs clinicians of the AMR pattern of circulating clone, which would add confidence to their prophylactic/treatment decision making and facilitate efficient patient care. Abstract : The molecular epidemiology of Salmonella Typhi circulating in India since early 1990s and its dominance is reported. An in-depth AMR profiling of the major drug-resistant lineage, 4.3.1, would help in management and for public health agencies in planning intervention strategies.