scholarly journals Pigeon-Associated Strains of Salmonella enterica Serovar Typhimurium Phage Type DT2 Have Genomic Rearrangements at rRNA Operons

2004 ◽  
Vol 72 (12) ◽  
pp. 7338-7341 ◽  
Author(s):  
R. Allen Helm ◽  
Steffen Porwollik ◽  
April E. Stanley ◽  
Stanley Maloy ◽  
Michael McClelland ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Phage Type ◽  
Laboratory Strain ◽  
Genomic Rearrangements ◽  
Serovar Typhimurium ◽  
The Common ◽  
Genomic Anomalies ◽  
Common Laboratory

ABSTRACT Strains from a subgroup of Salmonella enterica serovar Typhimurium frequently associated with pigeon infections were tested for genomic anomalies and virulence in mice. Some strains have a genomic inversion between rrn operons. Two prophages found in the common laboratory strain LT2 were absent. Pigeon-associated strains are still virulent in mice.

scholarly journals Characterization of the Genomes of a Diverse Collection of Salmonella enterica Serovar Typhimurium Definitive Phage Type 104

2008 ◽  
Vol 190 (24) ◽  
pp. 8155-8162 ◽  
Author(s):  
Fiona J. Cooke ◽  
Derek J. Brown ◽  
Maria Fookes ◽  
Derek Pickard ◽  
Alasdair Ivens ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Fragment Size ◽  
Phage Type ◽  
Antibiotic Resistance Genes ◽  
Serovar Typhimurium ◽  
Mlst Type ◽  
Plasmid Profiling ◽  
Type Sequence

ABSTRACT Salmonella enterica serovar Typhimurium definitive phage type 104 (DT104) has caused significant morbidity and mortality in humans and animals for almost three decades. We completed the full DNA sequence of one DT104 strain, NCTC13348, and showed that significant differences between the genome of this isolate and the genome of the previously sequenced strain Salmonella serovar Typhimurium LT2 are due to integrated prophage elements and Salmonella genomic island 1 encoding antibiotic resistance genes. Thirteen isolates of Salmonella serovar Typhimurium DT104 with different pulsed-field gel electrophoresis (PFGE) profiles were analyzed by using multilocus sequence typing (MLST), plasmid profiling, hybridization to a pan-Salmonella DNA microarray, and prophage-based multiplex PCR. All the isolates belonged to a single MLST type, sequence type ST19. Microarray data demonstrated that the gene contents of the 13 DT104 isolates were remarkably conserved. The PFGE DNA fragment size differences in these isolates could be explained to a great extent by differences in the prophage and plasmid contents. Thus, here the nature of variation in different Salmonella serovar Typhimurium DT104 isolates is further defined at the gene and whole-genome levels, illustrating how this phage type evolves over time.

scholarly journals Prevalence and Genetic Properties of Salmonella enterica Serovar Typhimurium Definitive Phage Type 104 Isolated from Rattus norvegicus and Rattus rattus House Rats in Yokohama City, Japan

2007 ◽  
Vol 73 (8) ◽  
pp. 2624-2630 ◽  
Author(s):  
Eiji Yokoyama ◽  
Soichi Maruyama ◽  
Hidenori Kabeya ◽  
Siro Hara ◽  
Shin Sata ◽  
...  
Keyword(s):  
Rattus Norvegicus ◽  
Gel Electrophoresis ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Phage Type ◽  
Rattus Rattus ◽  
Pulsed Field Gel Electrophoresis ◽  
Intestinal Contents ◽  
Serovar Typhimurium ◽  
J 24

ABSTRACT Salmonella enterica serovar Typhimurium was isolated from the intestinal contents of Rattus rattus and Rattus norvegicus house rats captured at two buildings, designated buildings J and YS, in Yokohama City, Japan. From October 1997 to September 1998, 52 of 339 (15.3%) house rats were found to carry Salmonella serovar Typhimurium definitive phage type 104 (DT104). In building J, 26 of 161 (16.1%) house rats carried DT104 over the 1-year study period, compared to 26 of 178 (14.6%) rats in building YS. The isolation rates of DT104 from R. rattus and R. norvegicus were similar in the two buildings. Most DT104 strains from building J (24 of 26) showed resistance to ampicillin, chloramphenicol, streptomycin, sulfisoxazole, and tetracycline and contained both the 1.0- and 1.2-kbp integrons, carrying genes pse1, pasppflo-like, aadA2, sulI, and tet(G). All DT104 strains from building YS were resistant to ampicillin and sulfisoxazole, and had the 1.2-kbp integron carrying pse1 and sulI. Cluster analysis of pulsed-field gel electrophoresis patterns of BlnI-digested DT104 DNAs showed that 22 of 26 DT104 strains from building J and 24 of 26 strains from building YS could be grouped into separate clusters each specific for the building origin. These results indicated that DT104 strains were prevalent in house rat colonies in each building and suggest that house rats may play an important role in the epidemiology of DT104.

Revival of an old problem: an increase in Salmonella enterica serovar Typhimurium definitive phage type 8 infections in 2010 in England and Northern Ireland linked to duck eggs

2011 ◽  
Vol 140 (1) ◽  
pp. 146-149 ◽  
Author(s):  
D. J. NOBLE ◽  
C. LANE ◽  
C. L. LITTLE ◽  
R. DAVIES ◽  
E. De PINNA ◽  
...  
Keyword(s):  
Northern Ireland ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Strong Association ◽  
Phage Type ◽  
Control Measures ◽  
Serovar Typhimurium ◽  
Duck Egg ◽  
The Uk ◽  
The Impact

SUMMARYSalmonella enterica serovar Typhimurium definitive phage type (DT) 8 is uncommon in humans in the UK. In July 2010, the Health Protection Agency reported an excess isolation rate of pan-susceptible S. Typhimurium DT8 in England and Northern Ireland. By the end of October, this amounted to 81 laboratory-confirmed human cases for all regions of England and Northern Ireland in 2010, an increase of 26% and 41% on 2009 and 2008, respectively. Descriptive epidemiological investigation found a strong association with infection and consumption of duck eggs. Duck eggs contaminated with S. Typhimurium DT8 were collected from a patient's home and also at farms in the duck-egg supply chain. Although duck eggs form a small part of total UK eggs sales, there has been significant growth in sales in recent years. This is the first known outbreak of salmonellosis linked to duck eggs in the UK since 1949 and highlighted the impact of a changing food source and market on the re-emergence of salmonellosis linked to duck eggs. Control measures by the duck-egg industry should be improved along with a continued need to remind the public and commercial caterers of the potential high risks of contracting salmonellosis from duck eggs.

scholarly journals Involvement of a Salmonella Genomic Island 1 Gene in the Rumen Protozoan-Mediated Enhancement of Invasion for Multiple-Antibiotic-Resistant Salmonella enterica Serovar Typhimurium

2006 ◽  
Vol 75 (2) ◽  
pp. 792-800 ◽  
Author(s):  
Steve A. Carlson ◽  
Vijay K. Sharma ◽  
Zoe P. McCuddin ◽  
Mark A. Rasmussen ◽  
Sharon K. Franklin
Keyword(s):  
Salmonella Enterica ◽  
Genomic Island ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Phage Type ◽  
Reporter System ◽  
Antibiotic Resistant ◽  
Phage Types ◽  
Food Borne ◽  
Serovar Typhimurium ◽  
Invasion Assays

ABSTRACT Multiple-antibiotic-resistant Salmonella enterica serotype Typhimurium is a food-borne pathogen that may be more virulent than related strains lacking the multiresistance phenotype. Salmonella enterica serotype Typhimurium phage type DT104 is the most prevalent of these multiresistant/hypervirulent strains. Multiresistance in DT104 is conferred by an integron structure, designated Salmonella genomic island 1 (SGI1), while we recently demonstrated DT104 hyperinvasion mediated by rumen protozoa (RPz) that are normal flora of cattle. Hyperinvasion was also observed in other Salmonella strains, i.e., other S. enterica serovar Typhimurium phage types and other S. enterica serovars, like S. enterica serovar Infantis, possessing SGI1, while DT104 strains lacking SGI1 were not hyperinvasive. Herein we attempted to identify SGI1 genes involved in the RPz-mediated hyperinvasion of Salmonella strains bearing SGI1. Transposon mutagenesis, coupled with a novel reporter system, revealed the involvement of an SGI1 gene previously designated SO13. Disruption of SO13 expression led to an abrogation of hyperinvasion as assessed by tissue culture invasion assays and by bovine challenge experiments. However, hyperinvasion was not observed in non-SGI1-bearing strains of Salmonella engineered to express SO13. That is, SO13 and another SGI1 gene(s) may coordinately upregulate invasion in DT104 exposed to RPz.

scholarly journals Diversity of Phage Types among Archived Cultures of the Demerec Collection of Salmonella enterica serovar Typhimurium Strains

2004 ◽  
Vol 70 (2) ◽  
pp. 664-669 ◽  
Author(s):  
Wolfgang Rabsch ◽  
R. Allen Helm ◽  
Abraham Eisenstark
Keyword(s):  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Phage Type ◽  
Phage Typing ◽  
Phage Types ◽  
Receptor Sites ◽  
Serovar Typhimurium ◽  
Phage Receptor ◽  
The Stability ◽  
Restriction Modification

ABSTRACT The existence of several thousand Salmonella enterica serovar Typhimurium LT2 and LT7 cultures originally collected by M. Demerec and sealed in agar stab vials for 33 to 46 years is a resource for evolutionary and mutational studies. Cultures from 74 of these vials, descendants of cells sealed and stored in nutrient agar stabs several decades ago, were phage typed by the Callow and Felix, Lilleengen, and Anderson systems. Among 53 LT2 archived strains, 16 had the same phage type as the nonarchival sequenced LT2 strain. The other 37 archived cultures differed in phage typing pattern from the sequenced strain. These 37 strains were divided into 10 different phage types. Among the 19 LT7 strains, only one was similar to the parent by phage typing, while 18 were different. These 18 strains fell into eight different phage types. The typing systems were developed to track epidemics from source to consumer, as well as geographic spread. The value of phage typing is dependent upon the stability of the phage type of any given strain throughout the course of the investigation. Thus, the variation over time observed in these archived cultures is particularly surprising. Possible mechanisms for such striking diversity may include loss of prophages, prophage mosaics as a result of recombination events, changes in phage receptor sites on the bacterial cell surface, or mutations in restriction-modification systems.

scholarly journals A brief overview of emergencies and dissemination of Shiga-toxin-producing E. coli (STEC) and Salmonella enterica serovar Typhimurium DT104 in humans and food producing animals

2020 ◽  
Vol 13 (2) ◽  
pp. 5-15
Author(s):  
Maja Velhner ◽  
Branko Velebit ◽  
Dalibor Todorović ◽  
Miloš Pelić ◽  
Suzana Vidaković Knežević ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Shiga Toxin ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Management Practice ◽  
Phage Type ◽  
Resistance Mechanisms ◽  
Transmission Mechanisms ◽  
Serovar Typhimurium

Shiga-toxin-producing Escherichia coli (STEC) and Salmonella enterica serovar Typhimurium (STDT104) are foodborne pathogens of public health significance. It is less known that Shiga-toxin-producing Escherichia coli (with cattle being the most probable natural reservoir) can be isolated from pigs, sheep and wildlife as well. The basic information about detection of Shiga-toxin-producing genes in STEC as well as the origin of Salmonella Typhimurium definite phage type 4 (STDT4) the virulence and resistance mechanisms including their distribution in the world is presented. Due to the foodborne transmission mechanisms we emphasize the role of veterinary scientist in Serbia in implementing good management practice on animal farms and in strengthening laboratory diagnostic capacities.

scholarly journals DNA Amplification and Rearrangements in Archival Salmonella enterica Serovar Typhimurium LT2 Cultures

2004 ◽  
Vol 186 (6) ◽  
pp. 1678-1682 ◽  
Author(s):  
Steffen Porwollik ◽  
Rita Mei-Yee Wong ◽  
R. Allen Helm ◽  
Kelly K. Edwards ◽  
Michael Calcutt ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Room Temperature ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Dna Amplification ◽  
Genomic Rearrangements ◽  
Pcr Analysis ◽  
Serovar Typhimurium ◽  
Over 40 Years ◽  
Over Time ◽  
Genomic Duplication

ABSTRACT Variations in genome size and gene order were observed in archival Salmonella enterica serovar Typhimurium cultures stored for over 40 years. In one strain, microarray analysis revealed a large, stable amplification. PCR analysis of the same strain revealed a genomic duplication that underwent a translocation. Other strains had smaller duplications and deletions. These results demonstrate that storage in stabs over time at room temperature not only allows for further bacterial growth but also may produce an environment that selects for a variety of mutations, including genomic rearrangements.

scholarly journals 1-Methylguanosine-Deficient tRNA of Salmonella enterica Serovar Typhimurium Affects Thiamine Metabolism

2003 ◽  
Vol 185 (3) ◽  
pp. 750-759 ◽  
Author(s):  
Glenn R. Björk ◽  
Kristina Nilsson
Keyword(s):  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Slow Growth ◽  
Carbon Sources ◽  
Gene Mutations ◽  
Gene Encoding ◽  
Translation Fidelity ◽  
Serovar Typhimurium ◽  
Purine Pathway ◽  
The Common

ABSTRACT In Salmonella enterica serovar Typhimurium a mutation in the purF gene encoding the first enzyme in the purine pathway blocks, besides the synthesis of purine, the synthesis of thiamine when glucose is used as the carbon source. On carbon sources other than glucose, a purF mutant does not require thiamine, since the alternative pyrimidine biosynthetic (APB) pathway is activated. This pathway feeds into the purine pathway just after the PurF biosynthetic step and upstream of the intermediate 4-aminoimidazolribotide, which is the common intermediate in purine and thiamine synthesis. The activity of this pathway is also influenced by externally added pantothenate. tRNAs from S. enterica specific for leucine, proline, and arginine contain 1-methylguanosine (m1G37) adjacent to and 3′ of the anticodon (position 37). The formation of m1G37 is catalyzed by the enzyme tRNA(m1G37)methyltransferase, which is encoded by the trmD gene. Mutations in this gene, which result in an m1G37 deficiency in the tRNA, in a purF mutant mediate PurF-independent thiamine synthesis. This phenotype is specifically dependent on the m1G37 deficiency, since several other mutations which also affect translation fidelity and induce slow growth did not cause PurF-independent thiamine synthesis. Some antibiotics that are known to reduce the efficiency of translation also induce PurF-independent thiamine synthesis. We suggest that a slow decoding event at a codon(s) read by a tRNA(s) normally containing m1G37 is responsible for the PurF-independent thiamine synthesis and that this event causes a changed flux in the APB pathway.

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