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Infection and Immunity Aug 2018serovar Typhimurium is one of approximately 2,500 distinct serovars of the genus but is exceptional in its wide distribution in the environment, livestock, and wild... (Review)
Review
serovar Typhimurium is one of approximately 2,500 distinct serovars of the genus but is exceptional in its wide distribution in the environment, livestock, and wild animals. Typhimurium causes a large proportion of nontyphoidal (NTS) infections, accounting for a quarter of infections, second only to serovar Enteritidis in incidence. Typhimurium was once considered the archetypal broad-host-range serovar due to its wide distribution in livestock and wild animals, and much of what we know of the interaction of with the host comes from research using a small number of laboratory strains of the serovar (LT2, SL1344, and ATCC 14028). But it has become clear that these strains do not reflect the genotypic or phenotypic diversity of Typhimurium. Here, we review the epidemiological record of Typhimurium and studies of the host-pathogen interactions of diverse strains of Typhimurium. We present the concept of distinct pathovariants of Typhimurium that exhibit diversity of host range, distribution in the environment, pathogenicity, and risk to food safety. We review recent evidence from whole-genome sequencing that has revealed the extent of genomic diversity of Typhimurium pathovariants, the genomic basis of differences in the level of risk to human and animal health, and the molecular epidemiology of prominent strains. An improved understanding of the impact of genome variation of bacterial pathogens on pathogen-host and pathogen-environment interactions has the potential to improve quantitative risk assessment and reveal how new pathogens evolve.
Topics: Animals; Biological Variation, Population; Food Microbiology; Food Safety; Genetic Variation; Genotype; Host Specificity; Host-Pathogen Interactions; Humans; Incidence; Molecular Epidemiology; Salmonella Infections; Salmonella Infections, Animal; Salmonella typhimurium
PubMed: 29784861
DOI: 10.1128/IAI.00079-18 -
Gut Microbes 2016Bacteria-mediated tumor therapy using Salmonella enterica serovar Typhimurium is a therapeutic option with great potential. Numerous studies explored the potential of... (Review)
Review
Bacteria-mediated tumor therapy using Salmonella enterica serovar Typhimurium is a therapeutic option with great potential. Numerous studies explored the potential of Salmonella Typhimurium for therapeutic applications, however reconciling safety with vectorial efficacy remains a major issue. Recently we have described a conditionally attenuated Salmonella vector that is based on genetic lipopolysaccharide modification. This vector combines strong attenuation with appropriate anti-tumor properties by targeting various cancerous tissues in vivo. Therefore, it was promoted as an anti-tumor agent. In this addendum, we summarize these findings and demonstrate additional optimization steps that may further improve the therapeutic efficacy of our vector strain.
Topics: Animals; Biological Therapy; Humans; Immunotherapy; Neoplasms; Salmonella typhimurium
PubMed: 26939530
DOI: 10.1080/19490976.2016.1155021 -
PloS One 2017Endemic infections with the common avian pathogen Salmonella enterica subspecies enterica serovar Typhimurium (Salmonella Typhimurium) may incur a significant cost on...
Endemic infections with the common avian pathogen Salmonella enterica subspecies enterica serovar Typhimurium (Salmonella Typhimurium) may incur a significant cost on the host population. In this study, we determined the potential of endemic Salmonella infections to reduce the reproductive success of blue (Cyanistes caeruleus) and great (Parus major) tits by correlating eggshell infection with reproductive parameters. The fifth egg of each clutch was collected from nest boxes in 19 deciduous forest fragments. Out of the 101 sampled eggs, 7 Salmonella Typhimurium isolates were recovered. The low bacterial prevalence was reflected by a similarly low serological prevalence in the fledglings. In this study with a relatively small sample size, presence of Salmonella did not affect reproductive parameters (egg volume, clutch size, number of nestlings and number of fledglings), nor the health status of the fledglings. However, in order to clarify the impact on health and reproduction a larger number of samples have to be analyzed. Phage typing showed that the isolates belonged to the definitive phage types (DT) 193 and 99, and multi-locus variable number tandem repeat analysis (MLVA) demonstrated a high similarity among the tit isolates, but distinction to human isolates. These findings suggest the presence of passerine-adapted Salmonella strains in free-ranging tit populations with host pathogen co-existence.
Topics: Animals; Antibodies, Bacterial; Belgium; Enzyme-Linked Immunosorbent Assay; Genes, Bacterial; Passeriformes; Reproduction; Salmonella Phages; Salmonella typhimurium; Species Specificity
PubMed: 29112955
DOI: 10.1371/journal.pone.0187640 -
International Journal of Molecular... Jan 2022The rapid identification of bacterial antibiotic susceptibility is pivotal to the rational administration of antibacterial drugs. In this study, cefotaxime (CTX)-derived...
The rapid identification of bacterial antibiotic susceptibility is pivotal to the rational administration of antibacterial drugs. In this study, cefotaxime (CTX)-derived resistance in (abbr. CTX-) during 3 months of exposure was rapidly recorded using a portable Raman spectrometer. The molecular changes that occurred in the drug-resistant strains were sensitively monitored in whole cells by label-free surface-enhanced Raman scattering (SERS). Various degrees of resistant strains could be accurately discriminated by applying multivariate statistical analyses to bacterial SERS profiles. Minimum inhibitory concentration (MIC) values showed a positive linear correlation with the relative Raman intensities of /, and the R reached 0.9962. The SERS results were consistent with the data obtained by MIC assays, mutant prevention concentration (MPC) determinations, and Kirby-Bauer antibiotic susceptibility tests (K-B tests). This preliminary proof-of-concept study indicates the high potential of the SERS method to supplement the time-consuming conventional method and help alleviate the challenges of antibiotic resistance in clinical therapy.
Topics: Anti-Bacterial Agents; Bacteria; Drug Resistance, Bacterial; Drug Resistance, Microbial; Humans; Salmonella Infections; Salmonella typhimurium; Spectrum Analysis, Raman
PubMed: 35163280
DOI: 10.3390/ijms23031356 -
Food Microbiology Dec 2021Bacterial food poisoning cases due to Salmonella have been linked with a variety of poultry products. This study evaluated the effects of a Salmonella-specific Lytic...
Bacterial food poisoning cases due to Salmonella have been linked with a variety of poultry products. This study evaluated the effects of a Salmonella-specific Lytic bacteriophage and Lactobionic acid (LBA) on Salmonella Typhimurium DT 104 growth on raw chicken breast meat. Each chicken breast was randomly assigned to a treatment group (Control, DI water, phage 1%, phage 5%, LBA 10 mg/mL, LBA 20 mg/mL, and phage 5% + LBA 20 mg/mL) with four chicken breasts per group. Samples were inoculated with 10 CFU/mL of Salmonella and stored at 4 °C for 30 min. The inoculated chicken breasts were randomly assigned to different storage time (0 h, 1 h, 24 h, or 48 h). Both time and treatment showed significance reduction (P < 0.0001) of microbial growth. The weight loss was significantly different (P < 0.0001) between treatments. The LBA treatments were not effective when compared to the control group, but Lytic bacteriophage significantly reduced the amount of microbial growth.
Topics: Animals; Chickens; Disaccharides; Food Preservation; Food Storage; Meat; Salmonella Phages; Salmonella typhimurium
PubMed: 34416962
DOI: 10.1016/j.fm.2021.103862 -
Scientific Reports Feb 2020Salmonella typhimurium is a pathogenic gram-negative bacterium, which is found primarily in the intestinal lumen. It often causes diarrhea in infants and young children...
Salmonella typhimurium is a pathogenic gram-negative bacterium, which is found primarily in the intestinal lumen. It often causes diarrhea in infants and young children and leads to food poisoning. Drug resistance of Salmonella typhimurium presented serious complications in clinical patients. In this study, we investigated the antibiotic susceptibility of Salmonella typhimurium standard strain L forms to the third and forth generation cephalosporins, in order to control and eliminate Salmonella typhimurium L forms in infection treatment. Salmonella typhimurium L forms were induced by β-lactam antibiotic cefazolin in the culture medium of bacterial L forms. The antibiotic susceptibility of Salmonella typhimurium L forms was analyzed by K-B drug susceptibility testing. The change trend of drug susceptibility and resistance of Salmonella typhimurium L forms was obtained in accordance with USA clinical and laboratory standards institute (CLSI) evaluation data and statistical analysis. Drug resistance of Salmonella typhimurium L forms showed little increasing trend compared with their parent bacteria. The L form inhibition zone was smaller than in the parent bacteria. However, the drug susceptibility of L forms of Salmonella typhimurium to the third and forth generation cephalosporins remained sensitive.The antibiotic susceptibility of Salmonella typhimurium L forms to the third and forth generation cephalosporins remains sensitive, and the combined use of multi-antibiotics is a convenient and effective method to reduce Salmonella typhimurium L forms occurrence.
Topics: Anti-Bacterial Agents; Cephalosporins; Colony Count, Microbial; Microbial Sensitivity Tests; Salmonella typhimurium; Staining and Labeling
PubMed: 32080217
DOI: 10.1038/s41598-020-59456-8 -
Journal of Bacteriology Aug 1972The addition of mannitol to cultures of Salmonella typhimurium mutants missing mannitol-1-phosphate dehydrogenase causes stasis or lysis. Mannitol-1-phosphate...
The addition of mannitol to cultures of Salmonella typhimurium mutants missing mannitol-1-phosphate dehydrogenase causes stasis or lysis. Mannitol-1-phosphate accumulates intracellularly to concentrations of 20 mm. The incorporation of acetate into lipid is inhibited before cell wall, protein, or nucleic acid synthesis.
Topics: Acetates; Alcohol Oxidoreductases; Bacterial Proteins; Bacteriolysis; Carbon Isotopes; Cell Wall; Chromatography, Paper; Genetics, Microbial; Lipids; Mannitol; Microbial Sensitivity Tests; Mutation; Nucleic Acids; Phenylalanine; Pimelic Acids; Salmonella typhimurium; Stereoisomerism; Time Factors; Tritium; Uracil
PubMed: 4559727
DOI: 10.1128/jb.111.2.351-355.1972 -
Microbiology Spectrum Sep 2017Transmission and virulence are central aspects of pathogen evolution. However, in many cases their interconnection has proven difficult to assess by experimentation.... (Review)
Review
Transmission and virulence are central aspects of pathogen evolution. However, in many cases their interconnection has proven difficult to assess by experimentation. Here we discuss recent advances from a mouse model for diarrhea. Mouse models mimic the enhanced susceptibility of antibiotic-treated individuals to nontyphoidal salmonellosis. In streptomycin-pretreated mice, subspecies 1 serovar Typhimurium efficiently colonizes the gut lumen and elicits pronounced enteropathy. In the host's gut, Typhimurium forms two subpopulations that cooperate to elicit disease and optimize transmission. The disease-causing subpopulation expresses a set of dedicated virulence factors (the type 3 secretion system 1 [TTSS-1]) that drive gut tissue invasion. The virulence factor expression is "costly" by retarding the growth rate and exposing the pathogen to innate immune defenses within the gut tissue. These costs are compensated by the gut inflammation (a "public good") that is induced by the invading subpopulation. The inflamed gut lumen fuels Typhimurium growth, in particular that of the TTSS-1 "off" subpopulation. The latter grows up to very high densities and promotes transmission. Thus, both phenotypes cooperate to elicit disease and ensure transmission. This system has provided an experimental framework for studying within-host evolution of pathogen virulence, how cooperative virulence is stabilized, and how environmental changes (e.g., antibiotic therapy) affect the transmission of the virulent genotype.
Topics: Animals; Anti-Bacterial Agents; Bacterial Proteins; Biological Evolution; Host-Pathogen Interactions; Humans; Salmonella Infections; Salmonella typhimurium; Virulence
PubMed: 28884670
DOI: 10.1128/microbiolspec.MTBP-0012-2016 -
Microbiology (Reading, England) May 2024subsp. Typhimurium and its monophasic variant I 1;4,[5],12:i:- (MVST) are responsible for thousands of reported cases of salmonellosis each year in Canada, and...
subsp. Typhimurium and its monophasic variant I 1;4,[5],12:i:- (MVST) are responsible for thousands of reported cases of salmonellosis each year in Canada, and countries worldwide. We investigated . Typhimurium and MVST isolates recovered from raw shellfish harvested in Atlantic Canada by the Canadian Food Inspection Agency (CFIA) over the past decade, to assess the potential impact of these isolates on human illness and to explore possible routes of shellfish contamination. Whole-genome sequence analysis was performed on 210 isolates of . Typhimurium and MVST recovered from various food sources, including shellfish. The objective was to identify genetic markers linked to ST-99, a sequence type specifically associated with shellfish, which could explain their high prevalence in shellfish. We also investigated the genetic similarity amongst CFIA ST-99 isolates recovered in different years and geographical locations. Finally, the study aimed to enhance the molecular serotyping of ST-99 isolates, as they are serologically classified as MVST but are frequently misidentified as . Typhimurium through sequence analysis. To ensure recovery of ST-99 from shellfish was not due to favourable growth kinetics, we measured the growth rates of these isolates relative to other and determined that ST-99 did not have a faster growth rate and/or shorter lag phase than other evaluated. The CFIA ST-99 isolates from shellfish were highly clonal, with up to 81 high-quality single nucleotide variants amongst isolates. ST-99 isolates both within the CFIA collection and those isolated globally carried numerous unique deletions, insertions and mutations in genes, including some considered important for virulence, such as gene deletions in the type VI secretion system. Interestingly, several of these genetic characteristics appear to be unique to North America. Most notably was a large genomic region showing a high prevalence in genomes from Canadian isolates compared to those from the USA. Although the functions of the majority of the proteins encoded within this region remain unknown, the genes and , known to be protective against UV light damage, were present. While this study did not specifically examine the effects of mutations and insertions, results indicate that these isolates may be adapted to survive in specific environments, such as ocean water, where wild birds and/or animals serve as the natural hosts. Our hypothesis is reinforced by a global phylogenetic analysis, which indicates that isolates obtained from North American shellfish and wild birds are infrequently connected to isolates from human sources. These findings suggest a distinct ecological niche for ST-99, potentially indicating their specialization and adaptation to non-human hosts and environments, such as oceanic habitats.
Topics: Shellfish; Salmonella typhimurium; Canada; Multilocus Sequence Typing; Whole Genome Sequencing; Animals; Humans; Genome, Bacterial; Food Microbiology; Phylogeny
PubMed: 38753417
DOI: 10.1099/mic.0.001456 -
Pathogens and Disease Jul 2016Salmonella enterica serovar Typhimurium, an enteric pathogen that causes a self-limiting gastroenteritis, forms biofilms on different surfaces. In sub-Saharan Africa,...
Salmonella enterica serovar Typhimurium, an enteric pathogen that causes a self-limiting gastroenteritis, forms biofilms on different surfaces. In sub-Saharan Africa, Salmonella Typhimurium of a novel sequence type (ST) 313 was identified and produces septicemia in the absence of gastroenteritis. No animal reservoir has been identified, and it is hypothesized that transmission occurs via human to human. In this study, we show that invasive Salmonella Typhimurium ST313 strains from Mali are poor biofilm producers compared to Salmonella Typhimurium ST19 strains, which are found worldwide and are known to be associated with gastroenteritis. We evaluated biofilms using crystal violet staining, examination of the red, dry and rough morphotype, pellicle formation and a continuous flow system. One month-old Salmonella Typhimurium ST19 colonies survived in the absence of exogenous nutrients and were highly resistant to sodium hypochlorite treatment compared to Salmonella Typhimurium ST313. This study for the first time demonstrates the comparative biofilm-forming ability and long-term survival of clinical Salmonella Typhimurium ST19 and ST313 isolates. Salmonella Typhimurium ST19 strains are strong biofilm producers and can survive desiccation compared to Salmonella Typhimurium ST313 that form weak biofilms and survive poorly following desiccation. Our data suggest that like Salmonella Typhi, Salmonella Typhimurium ST313 lack mechanisms that allow it to persist in the environment.
Topics: Biofilms; Disinfectants; Microbial Viability; Phenotype; Salmonella Infections; Salmonella typhimurium; Sodium Hypochlorite
PubMed: 27222487
DOI: 10.1093/femspd/ftw049