scholarly journals Salmonella enterica serovar Typhimurium ST313 responsible for gastroenteritis in the UK are genetically distinct from isolates causing bloodstream infections in Africa

2017 ◽  
Author(s):  
Philip M. Ashton ◽  
Sian V. Owen ◽  
Lukeki Kaindama ◽  
Will P. M. Rowe ◽  
Chris Lane ◽  
...  

AbstractThe ST313 sequence type of Salmonella enterica serovar Typhimurium causes invasive non-typhoidal salmonellosis amongst immunocompromised people in sub-Saharan Africa (sSA). Previously, two distinct phylogenetic lineages of ST313 have been described which have rarely been found outside sSA. Following the introduction of routine whole genome sequencing of Salmonella enterica by Public Health England in 2014, we have discovered that 2.7% (79/2888) of S. Typhimurium from patients in England and Wales are ST313. Of these isolates, 59/72 originated from stool and 13/72 were from extra-intestinal sites. The isolation of ST313 from extra-intestinal sites was significantly associated with travel to Africa (OR 12 [95% CI: 3,53]). Phylogenetic analysis revealed previously unsampled diversity of ST313, and distinguished UK-linked isolates causing gastroenteritis from African-associated isolates causing invasive disease. Bayesian evolutionary investigation suggested that the two African lineages diverged from their most recent common ancestors independently, circa 1796 and 1903. The majority of genome degradation of African ST313 lineage 2 is conserved in the UK ST313 lineages and only 10/44 pseudogenes were lineage 2-specific. The African lineages carried a characteristic prophage and antibiotic resistance gene repertoire, suggesting a strong selection pressure for these horizontally-acquired genetic elements in the sSA setting. We identified an ST313 isolate associated with travel to Kenya that carried a chromosomally-located blaCTX-M-15, demonstrating the continual evolution of this sequence type in Africa in response to selection pressure exerted by antibiotic usage.The S. Typhimurium ST313 sequence type has been primarily associated with invasive disease in Africa. Here, we highlight the power of routine whole-genome-sequencing by public health agencies to make epidemiologically-significant deductions that would be missed by conventional microbiological methods. The discovery of ST313 isolates responsible for gastroenteritis in the UK reveals new diversity in this important sequence type. We speculate that the niche specialization of sub-Saharan African ST313 lineages is driven in part by the acquisition of accessory genome elements.

mBio ◽  
2018 ◽  
Vol 9 (5) ◽  
Author(s):  
Alison E. Mather ◽  
Tu Le Thi Phuong ◽  
Yunfeng Gao ◽  
Simon Clare ◽  
Subhankar Mukhopadhyay ◽  
...  

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.


2020 ◽  
Vol 11 ◽  
Author(s):  
Anahit M. Sedrakyan ◽  
Zhanna A. Ktsoyan ◽  
Karine A. Arakelova ◽  
Magdalina K. Zakharyan ◽  
Alvard I. Hovhannisyan ◽  
...  

A total of 291 non-duplicate isolates of non-typhoidal Salmonella (NTS) were collected from the fecal samples of patients with salmonellosis in Armenia and Georgia during 1996–2016. The isolates were tested for resistance to antimicrobials, including extended-spectrum β-lactamases (ESBL). The high prevalence of multidrug-resistance (MDR) and ESBL-producer phenotypes was detected among Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) isolates collected from patients in Armenia between 1996 and 2016. A total of 36 MDR NTS isolates were subjected to whole genome sequencing (WGS) to determine the genetic background of antimicrobial resistance (AMR) and mobile genetic elements. All ESBL-producing S. Typhimurium isolates belonged to the same sequence type (ST328). The ESBL-producer phenotype was associated with plasmid-encoded CTX-M-5 production. A range of other plasmids was associated with resistance to other antimicrobials, including the MDR phenotype.


2018 ◽  
Vol 6 (5) ◽  
Author(s):  
Pedro Henrique N. Panzenhagen ◽  
Narayan C. Paul ◽  
Carlos A. Conte Junior ◽  
Renata G. Costa ◽  
Dália P. Rodrigues ◽  
...  

ABSTRACT Salmonella enterica serovar Typhimurium strains isolated from systemic sites outside sub-Saharan Africa have been rarely sequenced. Here, we report the draft genome sequences of S . Typhimurium sequence type 19 (ST19) ( n = 9), ST1649 ( n = 1), and ST313 ( n = 1) strains isolated from human systemic (e.g., blood) and nonsystemic (e.g., stool and wounds) sites in Brazil.


2017 ◽  
Vol 5 (46) ◽  
Author(s):  
Najwa Syahirah Roslan ◽  
Shagufta Jabeen ◽  
Nurulfiza Mat Isa ◽  
Abdul Rahman Omar ◽  
Mohd Hair Bejo ◽  
...  

ABSTRACT Salmonella enterica subsp. enterica serovar Typhimurium is one of several well-categorized Salmonella serotypes recognized globally. Here, we report the whole-genome sequence of S. Typhimurium strain UPM 260, isolated from a broiler chicken.


2021 ◽  
Vol 12 ◽  
Author(s):  
Lili Li ◽  
Rikke Heidemann Olsen ◽  
Anhua Song ◽  
Jian Xiao ◽  
Chong Wang ◽  
...  

Extended-spectrum β-lactamases (ESBLs) production and (fluoro)quinolone (FQ) resistance among Salmonella pose a public health threat. The objective of this study was the phenotypic and genotypic characterization of an ESBL-producing and nalidixic acid-resistant Salmonella enterica serovar Gloucester isolate (serotype 4:i:l,w) of sequence type 34 (ST34) from ready-to-eat (RTE) meat products in China. Whole-genome short and long read sequencing (HiSeq and MinION) results showed that it contained blaCTX–M–55, qnrS1, and tetB genes, with blaCTX–M–55 and qnrS1 located in chromosomal IS26-mediated composite transposon (IS26–qnrS1–IS3–Tn3–orf–blaCTX–M–55–ISEcp1–IS26). The same genetic structure was found in the chromosome of S. enterica subsp. enterica serovar Typhimurium strain and in several plasmids of Escherichia coli, indicating that the IS26-mediated composite transposon in the chromosome of S. Gloucester may originate from plasmids of E. coli and possess the ability to disseminate to Salmonella and other bacterial species. Besides, the structural unit qnrS1–IS3–Tn3–orf–blaCTX–M–55 was also observed to be linked with ISKpn19 in both the chromosomes and plasmids of various bacteria species, highlighting the contribution of the insertion sequences (IS26 and ISKpn19) to the co-dissemination of blaCTX–M–55 and qnrS1. To our knowledge, this is the first description of chromosomal blaCTX–M–55 and qnrS in S. Gloucester from RTE meat products. Our work expands the host range and provides additional evidence of the co-transfer of blaCTX–M–55 and qnrS1 among different species of Salmonella through the food chain.


2021 ◽  
Vol 12 ◽  
Author(s):  
Naoshi Ando ◽  
Tsuyoshi Sekizuka ◽  
Eiji Yokoyama ◽  
Yoshiyuki Aihara ◽  
Noriko Konishi ◽  
...  

In Japan’s Kanto region, the number of Salmonella enterica serovar Chester infections increased temporarily between 2014 and 2016. Concurrently with this temporal increase in the Kanto region, S. Chester isolates belonging to one clonal group were causing repetitive outbreaks in Europe. A recent study reported that the European outbreaks were associated with travelers who had been exposed to contaminated food in Morocco, possibly seafood. Because Japan imports a large amount of seafood from Morocco, we aimed to establish whether the temporal increase in S. Chester infections in the Kanto region was associated with imported Moroccan seafood. Short sequence reads from the whole-genome sequencing of 47 S. Chester isolates from people in the Kanto region (2014–2016), and the additional genome sequences from 58 isolates from the European outbreaks, were analyzed. The reads were compared with the complete genome sequence from a S. Chester reference strain, and 347 single nucleotide polymorphisms (SNPs) were identified. These SNPs were used in this study. Cluster and Bayesian cluster analyses showed that the Japanese and European isolates fell into two different clusters. Therefore, ΦPT and IAS values were calculated to evaluate genetic differences between these clusters. The results revealed that the Japanese and European isolates were genetically distinct populations. Our root-to-tip analysis showed that the Japanese isolates originating from one clone had accumulated mutations, suggesting that an emergence of this organism occurred. A minimum spanning tree analysis demonstrated no correlation between genetic and geographical distances in the Japanese isolates, suggesting that the emergence of the serovar in the Kanto region did not involve person-to-person contact; rather, it occurred through food consumption. The dN/dS ratio indicated that the Japanese strain has evolved under positive selection pressure. Generally, a population of bacterial clones in a reservoir faces negative selection pressure. Therefore, the Japanese strain must have existed outside of any reservoir during its emergence. In conclusion, S. Chester isolates originating from one clone probably emerged in the Kanto region via the consumption of contaminated foods other than imported Moroccan seafood. The emerging strain may have not established a reservoir for survival in the food supply chain resulting in its disappearance after 2017.


2017 ◽  
Vol 85 (9) ◽  
Author(s):  
Edna M. Ondari ◽  
Jennifer N. Heath ◽  
Elizabeth J. Klemm ◽  
Gemma Langridge ◽  
Lars Barquist ◽  
...  

ABSTRACT The ST313 pathovar of Salmonella enterica serovar Typhimurium contributes to a high burden of invasive disease among African infants and HIV-infected adults. It is characterized by genome degradation (loss of coding capacity) and has increased resistance to antibody-dependent complement-mediated killing compared with enterocolitis-causing strains of S. Typhimurium. Vaccination is an attractive disease-prevention strategy, and leading candidates focus on the induction of bactericidal antibodies. Antibody-resistant strains arising through further gene deletion could compromise such a strategy. Exposing a saturating transposon insertion mutant library of S. Typhimurium to immune serum identified a repertoire of S. Typhimurium genes that, when interrupted, result in increased resistance to serum killing. These genes included several involved in bacterial envelope biogenesis, protein translocation, and metabolism. We generated defined mutant derivatives using S. Typhimurium SL1344 as the host. Based on their initial levels of enhanced resistance to killing, yfgA and sapA mutants were selected for further characterization. The S. Typhimurium yfgA mutant lost the characteristic Salmonella rod-shaped appearance, exhibited increased sensitivity to osmotic and detergent stress, lacked very long lipopolysaccharide, was unable to invade enterocytes, and demonstrated decreased ability to infect mice. In contrast, the S. Typhimurium sapA mutants had similar sensitivity to osmotic and detergent stress and lipopolysaccharide profile and an increased ability to infect enterocytes compared with the wild type, but it had no increased ability to cause in vivo infection. These findings indicate that increased resistance to antibody-dependent complement-mediated killing secondary to genetic deletion is not necessarily accompanied by increased virulence and suggest the presence of different mechanisms of antibody resistance.


2019 ◽  
Vol 63 (6) ◽  
Author(s):  
Maria Borowiak ◽  
Jens A. Hammerl ◽  
Carlus Deneke ◽  
Jennie Fischer ◽  
Istvan Szabo ◽  
...  

ABSTRACT We characterized eight mcr-5-positive Salmonella enterica subsp. enterica serovar Typhimurium sequence type 34 (ST34) isolates obtained from pigs and meat in Germany. Five plasmid types were identified harboring mcr-5 on Tn6452 or putative mobile insertion cassettes. The mobility of mcr-5 was confirmed by integration of Tn6452 into the bacterial chromosomes of two strains and the detection of conjugative mcr-5 plasmids. The association with mobile genetic elements might further enhance mcr-5 distribution.


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