In:
mBio, American Society for Microbiology, Vol. 9, No. 5 ( 2018-11-07)
Abstract:
Nontyphoidal Salmonella (NTS), particularly Salmonella enterica serovar Typhimurium, is among the leading etiologic agents of bacterial enterocolitis globally and a well-characterized cause of invasive disease (iNTS) in sub-Saharan Africa. In contrast, S . Typhimurium is poorly defined in Southeast Asia, a known hot spot for zoonotic disease with a recently described burden of iNTS disease. Here, we aimed to add insight into the epidemiology and potential impact of zoonotic transfer and antimicrobial resistance (AMR) in S . Typhimurium associated with iNTS and enterocolitis in Vietnam. We performed whole-genome sequencing and phylogenetic reconstruction on 85 human (enterocolitis, carriage, and iNTS) and 113 animal S . Typhimurium isolates isolated in Vietnam. We found limited evidence for the zoonotic transmission of S . Typhimurium. However, we describe a chain of events where a pandemic monophasic variant of S . Typhimurium (serovar I:4,[5],12:i:− sequence type 34 [ST34] ) has been introduced into Vietnam, reacquired a phase 2 flagellum, and acquired an IncHI2 multidrug-resistant plasmid. Notably, these novel biphasic ST34 S . Typhimurium variants were significantly associated with iNTS in Vietnamese HIV-infected patients. Our study represents the first characterization of novel iNTS organisms isolated outside sub-Saharan Africa and outlines a new pathway for the emergence of alternative Salmonella variants into susceptible human populations. IMPORTANCE Salmonella Typhimurium is a major diarrheal pathogen and associated with invasive nontyphoid Salmonella (iNTS) disease in vulnerable populations. We present the first characterization of iNTS organisms in Southeast Asia and describe a different evolutionary trajectory from that of organisms causing iNTS in sub-Saharan Africa. In Vietnam, the globally distributed monophasic variant of Salmonella Typhimurium, the serovar I:4,[5],12:i:− ST34 clone, has reacquired a phase 2 flagellum and gained a multidrug-resistant plasmid to become associated with iNTS disease in HIV-infected patients. We document distinct communities of S . Typhimurium and I:4,[5],12:i:− in animals and humans in Vietnam, despite the greater mixing of these host populations here. These data highlight the importance of whole-genome sequencing surveillance in a One Health context in understanding the evolution and spread of resistant bacterial infections.
Type of Medium:
Online Resource
ISSN:
2161-2129
,
2150-7511
DOI:
10.1128/mBio.01056-18
Language:
English
Publisher:
American Society for Microbiology
Publication Date:
2018
detail.hit.zdb_id:
2557172-2
