scholarly journals Global Genomic Epidemiology of Salmonella enterica Serovar Typhimurium DT104

2016 ◽  
Vol 82 (8) ◽  
pp. 2516-2526 ◽  
Author(s):  
Pimlapas Leekitcharoenphon ◽  
Rene S. Hendriksen ◽  
Simon Le Hello ◽  
François-Xavier Weill ◽  
Dorte Lau Baggesen ◽  
...  

ABSTRACTIt has been 30 years since the initial emergence and subsequent rapid global spread of multidrug-resistantSalmonella entericaserovar Typhimurium DT104 (MDR DT104). Nonetheless, its origin and transmission route have never been revealed. We used whole-genome sequencing (WGS) and temporally structured sequence analysis within a Bayesian framework to reconstruct temporal and spatial phylogenetic trees and estimate the rates of mutation and divergence times of 315S. Typhimurium DT104 isolates sampled from 1969 to 2012 from 21 countries on six continents. DT104 was estimated to have emerged initially as antimicrobial susceptible in ∼1948 (95% credible interval [CI], 1934 to 1962) and later became MDR DT104 in ∼1972 (95% CI, 1972 to 1988) through horizontal transfer of the 13-kbSalmonellagenomic island 1 (SGI1) MDR region into susceptible strains already containing SGI1. This was followed by multiple transmission events, initially from central Europe and later between several European countries. An independent transmission to the United States and another to Japan occurred, and from there MDR DT104 was probably transmitted to Taiwan and Canada. An independent acquisition of resistance genes took place in Thailand in ∼1975 (95% CI, 1975 to 1990). In Denmark, WGS analysis provided evidence for transmission of the organism between herds of animals. Interestingly, the demographic history of Danish MDR DT104 provided evidence for the success of the program to eradicateSalmonellafrom pig herds in Denmark from 1996 to 2000. The results from this study refute several hypotheses on the evolution of DT104 and suggest that WGS may be useful in monitoring emerging clones and devising strategies for prevention ofSalmonellainfections.

2018 ◽  
Vol 85 (4) ◽  
Author(s):  
Devin B. Holman ◽  
Bradley L. Bearson ◽  
Heather K. Allen ◽  
Daniel C. Shippy ◽  
Crystal L. Loving ◽  
...  

ABSTRACTSalmonellaspp. are estimated to cause 1.2 million cases of human foodborne illness each year in the United States, and pigs can often be asymptomatically colonized withSalmonellaspp. (>50% of farms). Recent reports state that 18.3% ofSalmonella entericaserovar Typhimurium isolates are resistant to ≥3 antimicrobial classes, and multidrug-resistant (MDR) strains are associated with an increased hospitalization rate and other complications. Chlortetracycline is commonly used in swine production to prevent/treat various diseases; therefore, chlortetracycline treatment of pigs unknowingly colonized with MDRSalmonellamay have collateral effects onSalmonellaspp. (and other gut bacteria). In this study, we determined the effect of in-feed chlortetracycline (400 g/ton) on shedding and colonization of pigs challenged with the MDRS. Typhimurium strain DT104 (n= 11/group). We also assessed the impact on the fecal microbiota over the 12-day experimental period and on the ileum, cecum, and tonsil microbiota at 7 days postinoculation (dpi). In MDRS. Typhimurium-inoculated pigs, chlortetracycline administration significantly increased fecal shedding at 2 dpi (+1.4 log10CFU/g;P < 0.001) and enhanced tonsil colonization (+3.1 log10CFU/g;P < 0.001). There were few major alterations detected in the gut or tonsillar microbiota of pigs treated with MDRS. Typhimurium and/or chlortetracycline. The tonsillar transcriptome was largely unaffected despite increased colonization by MDRS. Typhimurium following inoculation of the chlortetracycline-treated pigs. These results highlight the idea that chlortetracycline administration can enhance shedding and colonization of MDRS. Typhimurium in pigs, which could increase the risk of environmental dissemination of MDRSalmonellastrains.IMPORTANCESalmonellaspp. are an important cause of foodborne illness in North America, and pork products are associated with sporadic cases and outbreaks of human salmonellosis. Isolates ofSalmonellamay be resistant to multiple antibiotics, and infections with multidrug-resistant (MDR)Salmonellaspp. are more difficult to treat, leading to increased hospitalization rates. Swine operations commonly use antimicrobials, such as chlortetracycline, to prevent/treat infections, which may have collateral effects on pig microbial populations. Recently, we demonstrated that chlortetracycline induces the expression of genes associated with pathogenesis and invasion in MDRSalmonella entericaserovar Typhimuriumin vitro. In our current study, we show increased tonsillar colonization and fecal shedding of the MDRS. Typhimurium strain DT104 from pigs administered chlortetracycline. Therefore, pigs unknowingly colonized with multidrug-resistantSalmonellaspp. and receiving chlortetracycline for an unrelated infection may be at a greater risk for disseminating MDRSalmonellaspp. to other pigs and to humans through environmental or pork product contamination.


2013 ◽  
Vol 20 (10) ◽  
pp. 1491-1498 ◽  
Author(s):  
Estela Trebicka ◽  
Susan Jacob ◽  
Waheed Pirzai ◽  
Bryan P. Hurley ◽  
Bobby J. Cherayil

ABSTRACTRecent observations from Africa have rekindled interest in the role of serum bactericidal antibodies in protecting against systemic infection withSalmonella entericaserovar Typhimurium. To determine whether the findings are applicable to other populations, we analyzed serum samples collected from healthy individuals in the United States. We found that all but 1 of the 49 adult samples tested had robust bactericidal activity againstS. Typhimurium in a standardin vitroassay. The activity was dependent on complement and could be reproduced by immunoglobulin G (IgG) purified from the sera. The bactericidal activity was inhibited by competition with soluble lipopolysaccharide (LPS) fromS. Typhimurium but not fromEscherichia coli, consistent with recognition of a determinant in the O-antigen polysaccharide. Sera from healthy children aged 10 to 48 months also had bactericidal activity, although it was significantly less than in the adults, correlating with lower levels of LPS-specific IgM and IgG. The lone sample in our collection that lacked bactericidal activity was able to inhibit killing ofS. Typhimurium by the other sera. The inhibition correlated with the presence of an LPS-specific IgM and was associated with decreased complement deposition on the bacterial surface. Our results indicate that healthy individuals can have circulating antibodies to LPS that either mediate or inhibit killing ofS. Typhimurium. The findings contrast with the observations from Africa, which linked bactericidal activity to antibodies against anS. Typhimurium outer membrane protein and correlated the presence of inhibitory anti-LPS antibodies with human immunodeficiency virus infection.


2018 ◽  
Vol 84 (19) ◽  
Author(s):  
Mengfei Peng ◽  
Serajus Salaheen ◽  
Robert L. Buchanan ◽  
Debabrata Biswas

ABSTRACT Microbial horizontal gene transfer is a continuous process that shapes bacterial genomic adaptation to the environment and the composition of concurrent microbial ecology. This includes the potential impact of synthetic antibiotic utilization in farm animal production on overall antibiotic resistance issues; however, the mechanisms behind the evolution of microbial communities are not fully understood. We explored potential mechanisms by experimentally examining the relatedness of phylogenetic inference between multidrug-resistant Salmonella enterica serovar Typhimurium isolates and pathogenic Salmonella Typhimurium strains based on genome-wide single-nucleotide polymorphism (SNP) comparisons. Antibiotic-resistant S. Typhimurium isolates in a simulated farm environment barely lost their resistance, whereas sensitive S. Typhimurium isolates in soils gradually acquired higher tetracycline resistance under antibiotic pressure and manipulated differential expression of antibiotic-resistant genes. The expeditious development of antibiotic resistance and the ensuing genetic alterations in antimicrobial resistance genes in S. Typhimurium warrant effective actions to control the dissemination of Salmonella antibiotic resistance. IMPORTANCE Antibiotic resistance is attributed to the misuse or overuse of antibiotics in agriculture, and antibiotic resistance genes can also be transferred to bacteria under environmental stress. In this study, we report a unidirectional alteration in antibiotic resistance from susceptibility to increased resistance. Highly sensitive Salmonella enterica serovar Typhimurium isolates from organic farm systems quickly acquired tetracycline resistance under antibiotic pressure in simulated farm soil environments within 2 weeks, with expression of antibiotic resistance-related genes that was significantly upregulated. Conversely, originally resistant S. Typhimurium isolates from conventional farm systems lost little of their resistance when transferred to environments without antibiotic pressure. Additionally, multidrug-resistant S. Typhimurium isolates genetically shared relevancy with pathogenic S. Typhimurium isolates, whereas susceptible isolates clustered with nonpathogenic strains. These results provide detailed discussion and explanation about the genetic alterations and simultaneous acquisition of antibiotic resistance in S. Typhimurium in agricultural environments.


2017 ◽  
Vol 84 (5) ◽  
Author(s):  
M. Andrea Azcarate-Peril ◽  
Natasha Butz ◽  
Maria Belen Cadenas ◽  
Matthew Koci ◽  
Anne Ballou ◽  
...  

ABSTRACT Salmonella is estimated to cause one million foodborne illnesses in the United States every year. Salmonella -contaminated poultry products are one of the major sources of salmonellosis. Given the critical role of the gut microbiota in Salmonella transmission, a manipulation of the chicken intestinal microenvironment could prevent animal colonization by the pathogen. In Salmonella , the global regulator gene fnr ( f umarate n itrate r eduction) regulates anaerobic metabolism and is essential for adapting to the gut environment. This study tested the hypothesis that an attenuated Fnr mutant of Salmonella enterica serovar Typhimurium (attST) or prebiotic galacto-oligosaccharides (GOS) could improve resistance to wild-type Salmonella via modifications to the structure of the chicken gut microbiome. Intestinal samples from a total of 273 animals were collected weekly for 9 weeks to evaluate the impact of attST or prebiotic supplementation on microbial species of the cecum, duodenum, jejunum, and ileum. We next analyzed changes to the gut microbiome induced by challenging the animals with a wild-type Salmonella serovar 4,[5],12:r:− (Nal r ) strain and determined the clearance rate of the virulent strain in the treated and control groups. Both GOS and the attenuated Salmonella strain modified the gut microbiome but elicited alterations of different taxonomic groups. The attST produced significant increases of Alistipes and undefined Lactobacillus , while GOS increased Christensenellaceae and Lactobacillus reuteri . The microbiome structural changes induced by both treatments resulted in a faster clearance after a Salmonella challenge. IMPORTANCE With an average annual incidence of 13.1 cases/100,000 individuals, salmonellosis has been deemed a nationally notifiable condition in the United States by the Centers for Disease Control and Prevention (CDC). Earlier studies demonstrated that Salmonella is transmitted by a subset of animals (supershedders). The supershedder phenotype can be induced by antibiotics, ascertaining an essential role for the gut microbiota in Salmonella transmission. Consequently, modulation of the gut microbiota and modification of the intestinal microenvironment could assist in preventing animal colonization by the pathogen. Our study demonstrated that a manipulation of the chicken gut microbiota by the administration of an attenuated Salmonella strain or prebiotic galacto-oligosaccharides (GOS) can promote resistance to Salmonella colonization via increases of beneficial microorganisms that translate into a less hospitable gut microenvironment.


2019 ◽  
Vol 63 (10) ◽  
Author(s):  
Ying-Shu Liao ◽  
Bo-Han Chen ◽  
Yu-Ping Hong ◽  
Ru-Hsiou Teng ◽  
You-Wun Wang ◽  
...  

ABSTRACT Salmonella enterica serovar Goldcoast infection was rare in Taiwan; it was not detected in routine surveillance from 2004 to 2013. This serovar was first identified in 2014, but the frequency of infection remained low until 2017. From 2014 to 2016, all but one isolate was pan-susceptible. S. Goldcoast infections abruptly increased in 2018, and all isolates were multidrug-resistant (MDR). All MDR isolates harbored an IncHI2 plasmid, and the majority carried 14 antimicrobial resistance genes, aac(3)-IId, aadA22, aph(3′)-Ia, aph(6)-Id, blaTEM-1B, blaCTX-M-55, lnu(F), floR, qnrS13, arr-2, sul2, sul3, tet(A), and dfrA14. S. Goldcoast strains recovered in Taiwan and 96 of 99 strains from Germany, the Netherlands, the United Kingdom, and the United States belonged to sequence type 358 (ST358). Whole-genome single-nucleotide polymorphism and core genome multilocus sequence type analyses revealed that all strains of the ST358 clone shared a high degree of genetic relatedness. The present study highlighted that a dramatic increase in S. Goldcoast infections followed the emergence of MDR strains and indicated that a genetically closely related S. Goldcoast ST358 clone may have widespread significance internationally.


2019 ◽  
Vol 63 (6) ◽  
Author(s):  
Chand S. Mangat ◽  
Sadjia Bekal ◽  
Brent P. Avery ◽  
Geneviève Côté ◽  
Danielle Daignault ◽  
...  

ABSTRACT Salmonella enterica subsp. enterica serovar Dublin is a zoonotic pathogen that often leads to invasive bloodstream infections in humans that are multidrug resistant. Described here are the results of Canadian national surveillance of S. Dublin from 2003 to 2015 in humans and bovines, principally collected through the Canadian Integrated Program for Antibiotic Resistance Surveillance (CIPARS). An increase in human infections due to multidrug-resistant (MDR) S. Dublin was observed in 2010, many of which were bloodstream infections. Phylogenomic analysis of human and bovine isolates revealed a closely related network that differed by only 0 to 17 single nucleotide variants (SNVs), suggesting some potential transmission between humans and bovines. Phylogenomic comparison of global publicly available sequences of S. Dublin showed that Canadian isolates clustered closely with those from the United States. A high correlation between phenotypic and genotypic antimicrobial susceptibility was observed in Canadian isolates. IS26 replication was widespread among U.S. and Canadian isolates and caused the truncation and inactivation of the resistance genes strA and blaTEM-1B. A hybrid virulence and MDR plasmid (pN13-01125) isolated from a Canadian S. Dublin isolate was searched against NCBI SRA data of bacteria. The pN13-01125 coding sequences were found in 13 Salmonella serovars, but S. Dublin appears to be a specific reservoir. In summary, we have observed the rise of invasive MDR S. Dublin in humans in Canada and found that they are closely related to bovine isolates and to American isolates in their mobile and chromosomal contents.


2019 ◽  
Vol 8 (44) ◽  
Author(s):  
Emily L. McCutchen ◽  
Madeline Galac ◽  
Curtis Kapsak ◽  
Steven H. Hinrichs ◽  
Peter C. Iwen ◽  
...  

Salmonella enterica subsp. enterica serovar Corvallis is commonly reported in avian populations and avian by-products. We report the draft genome sequence of a multidrug-resistant S. Corvallis strain (NPHL 15376). To our knowledge, this is the first reported case of this serovar isolated from human blood in the United States.


2020 ◽  
Vol 88 (4) ◽  
Author(s):  
Daniel Hurley ◽  
Maria Hoffmann ◽  
Tim Muruvanda ◽  
Marc W. Allard ◽  
Eric W. Brown ◽  
...  

ABSTRACT Nontyphoidal Salmonella species are globally disseminated pathogens and are the predominant cause of gastroenteritis. The pathogenesis of salmonellosis has been extensively studied using in vivo murine models and cell lines, typically challenged with Salmonella enterica serovar Typhimurium. Although S. enterica serovars Enteritidis and Typhimurium are responsible for most of the human infections reported to the Centers for Disease Control and Prevention (CDC), several other serovars also contribute to clinical cases of salmonellosis. Despite their epidemiological importance, little is known about their infection phenotypes. Here, we report the virulence characteristics and genomes of 10 atypical S. enterica serovars linked to multistate foodborne outbreaks in the United States. We show that the murine RAW 264.7 macrophage model of infection is unsuitable for inferring human-relevant differences in nontyphoidal Salmonella infections, whereas differentiated human THP-1 macrophages allowed these isolates to be further characterized in a more human-relevant context.


2015 ◽  
Vol 59 (5) ◽  
pp. 2774-2779 ◽  
Author(s):  
Jason P. Folster ◽  
Davina Campbell ◽  
Julian Grass ◽  
Allison C. Brown ◽  
Amelia Bicknese ◽  
...  

ABSTRACTSalmonella entericais one of the most common causes of bacterial foodborne illness in the United States. Although mostSalmonellainfections are self-limiting, antimicrobial treatment of invasive salmonellosis is critical. The primary antimicrobial treatment options include fluoroquinolones or extended-spectrum cephalosporins, and resistance to these antimicrobial drugs may complicate treatment. At present,S. entericais composed of more than 2,600 unique serotypes, which vary greatly in geographic prevalence, ecological niche, and the ability to cause human disease, and it is important to understand and mitigate the source of human infection, particularly when antimicrobial resistance is found. In this study, we identified and characterized 19S. entericaserotype Albert isolates collected from food animals, retail meat, and humans in the United States during 2005 to 2013. All five isolates from nonhuman sources were obtained from turkeys or ground turkey, and epidemiologic data suggest poultry consumption or live-poultry exposure as the probable source of infection.S. entericaserotype Albert also appears to be geographically localized to the midwestern United States. All 19 isolates displayed multidrug resistance, including decreased susceptibility to fluoroquinolones and resistance to extended-spectrum cephalosporins. Turkeys are a likely source of multidrug-resistantS. entericaserotype Albert, and circulation of resistance plasmids, as opposed to the expansion of a single resistant strain, is playing a role. More work is needed to understand why these resistance plasmids spread and how their presence and the serotype they reside in contribute to human disease.


2018 ◽  
Vol 7 (4) ◽  
Author(s):  
Nicolás F. Cordeiro ◽  
Bruno D’Alessandro ◽  
Andrés Iriarte ◽  
Derek Pickard ◽  
Lucía Yim ◽  
...  

Multidrug-resistant Salmonella enterica isolates are an increasing problem worldwide; nevertheless, the mechanisms responsible for such resistance are rarely well defined. Multidrug-resistant S. enterica serovar Typhimurium isolates ST3224 and ST827 were collected from two patients.


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