scholarly journals Comparison of Genotypes of Salmonella enterica Serovar Enteritidis Phage Type 30 and 9c Strains Isolated during Three Outbreaks Associated with Raw Almonds

2010 ◽  
Vol 76 (11) ◽  
pp. 3723-3731 ◽  
Author(s):  
Craig T. Parker ◽  
Steven Huynh ◽  
Beatriz Qui�ones ◽  
Linda J. Harris ◽  
Robert E. Mandrell
Keyword(s):  
Salmonella Enterica ◽  
Genetic Relatedness ◽  
Phage Type ◽  
Variable Number Tandem Repeat ◽  
Variable Number ◽  
Comparative Genomic ◽  
Salmonella Enterica Serovar Enteritidis ◽  
Phage Types ◽  
Serovar Typhimurium ◽  
Genomic Indexing

ABSTRACT In 2000 to 2001, 2003 to 2004, and 2005 to 2006, three outbreaks of Salmonella enterica serovar Enteritidis were linked with the consumption of raw almonds. The S. Enteritidis strains from these outbreaks had rare phage types (PT), PT30 and PT9c. Clinical and environmental S. Enteritidis strains were subjected to pulsed-field gel electrophoresis (PFGE), multilocus variable-number tandem repeat analysis (MLVA), and DNA microarray-based comparative genomic indexing (CGI) to evaluate their genetic relatedness. All three methods differentiated these S. Enteritidis strains in a manner that correlated with PT. The CGI analysis confirmed that the majority of the differences between the S. Enteritidis PT9c and PT30 strains corresponded to bacteriophage-related genes present in the sequenced genomes of S. Enteritidis PT4 and S. enterica serovar Typhimurium LT2. However, PFGE, MLVA, and CGI failed to discriminate between S. Enteritidis PT30 strains related to outbreaks from unrelated clinical strains or between strains separated by up to 5 years. However, metabolic fingerprinting demonstrated that S. Enteritidis PT4, PT8, PT13a, and clinical PT30 strains metabolized l-aspartic acid, l-glutamic acid, l-proline, l-alanine, and d-alanine amino acids more efficiently than S. Enteritidis PT30 strains isolated from orchards. These data indicate that S. Enteritidis PT9c and 30 strains are highly related genetically and that PT30 orchard strains differ from clinical PT30 strains metabolically, possibly due to fitness adaptations.

scholarly journals A severe gastroenteritis outbreak of Salmonella enterica serovar Enteritidis PT8, with PFGE profile XbaI.0024 and MLVA profile 2-9-7-3-2 following a christening reception, Greece, 2016

2017 ◽  
Vol 146 (1) ◽  
pp. 28-36 ◽  
Author(s):  
G. MANDILARA ◽  
C. M. VASSALOS ◽  
A. CHRISOSTOMOU ◽  
K. KARADIMAS ◽  
E. MATHIOUDAKI ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Virulent Strain ◽  
Phage Type ◽  
Variable Number Tandem Repeat ◽  
Admission Rate ◽  
Variable Number ◽  
Molecular Techniques ◽  
Contributing Factors ◽  
Salmonella Enterica Serovar Enteritidis ◽  
Hospital Admission Rate

SUMMARYIn June 2016, a Salmonella enterica serovar Enteritidis outbreak (n = 56) occurred after a christening reception in Central Greece, mainly affecting previously healthy adults; one related death caused media attention. Patients suffered from profuse diarrhoea, fever and frequent vomiting episodes requiring prolonged hospitalisation and sick leave from work, with a 54% hospital admission rate. The majority of cases experienced serious illness within <12 h of attending the party. We investigated the outbreak to identify the source(s) of infection and contributing factors to the disease severity. From the retrospective cohort study, the cheesy penne pasta was the most likely vehicle of infection (relative risk 7·8; 95% confidence interval 3·6–16·8), explaining 79% of the cases. S. enterica ser. Enteritidis isolates were typed as phage-type PT8, pulsed-field gel electrophoresis type XbaI.0024, multiple locus variable-number tandem repeat analysis-type 2-9-7-3-2. The strain did not share the single-nucleotide polymorphism address of the concurrent European S. enterica ser. Enteritidis PT8 outbreak clusters. Following five consecutive years with no documented S. enterica ser. Enteritidis outbreaks in Greece, this outbreak, likely associated with a virulent strain, prompted actions towards the enhancement of the national Salmonella molecular surveillance and control programmes including the intensification of training of food handlers for preventing similar outbreaks in the future. Advanced molecular techniques were useful in distinguishing unrelated outbreak strains.

Multiple-locus variable-number tandem-repeat analysis for discriminating withinSalmonella entericaserovar Typhimurium definitive types and investigation of outbreaks

2010 ◽  
Vol 139 (7) ◽  
pp. 1050-1059 ◽  
Author(s):  
K. H. DYET ◽  
E. TURBITT ◽  
P. E. CARTER
Keyword(s):  
Tandem Repeat ◽  
Phage Type ◽  
Variable Number Tandem Repeat ◽  
Variable Number ◽  
Common Source ◽  
Reference Laboratory ◽  
Multiple Locus ◽  
Repeat Analysis ◽  
Phage Types ◽  
Serovar Typhimurium

SUMMARYThe discriminatory power of multiple-locus variable-number tandem-repeat analysis (MLVA) needs to be evaluated for allSalmonella entericasubspeciesentericaserovar Typhimurium (S. Typhimurium) phage types so that the power of this methodology is understood and results can be interpreted correctly during outbreak investigations. We evaluated the ability of MLVA to characterize four definitive phage types (DT) problematic in New Zealand. MLVA discriminated between DT104 isolates although there was very limited variation in the MLVA profiles for isolates with an RDNC phage type (reacts but does not conform to a recognized Typhimurium phage pattern) first observed in New Zealand's Enteric Reference Laboratory in May 2006. Most DT101 isolates had indistinguishable MLVA profiles or profiles that differed at one or two loci. This was also observed in DT160 isolates. MLVA may not identify all common-source outbreaks although it provided valuable data when applied to case isolates from twoS. Typhimurium outbreaks.

scholarly journals Emergence and clonal dissemination of Salmonella enterica serovar Enteritidis causing salmonellosis in Mauritius

2014 ◽  
Vol 8 (04) ◽  
pp. 454-460 ◽  
Author(s):  
Mohammad I Issack ◽  
Rene S Hendriksen ◽  
Eija Hyytiä-Trees ◽  
Christina A Svendsen ◽  
Matthew Mikoleit
Keyword(s):  
Salmonella Enterica ◽  
Susceptibility Testing ◽  
Genetic Relatedness ◽  
Financial Burden ◽  
Variable Number Tandem Repeat ◽  
Variable Number ◽  
Salmonella Enterica Serovar Enteritidis ◽  
Repeat Analysis ◽  
Invasive Infections ◽  
Major Producer

Introduction: For decades, Salmonella enterica serovar Enteritidis has been among the most prevalent serovars reported worldwide. However, it was rarely encountered in Mauritius until 2007; since then the number of non-typhoidal Salmonella serogroup O:9 (including serovar Enteritidis) increased. A study was conducted to investigate the genetic relatedness between S. Enteritidis isolates recovered in Mauritius from food and clinical specimens (stool, blood, and exudate). Methodology: Forty-seven isolates of S. Enteritidis obtained in 2009 from human stools, blood cultures and exudates, and from food specimens were characterized by antimicrobial susceptibility testing and Multiple-Locus Variable-number tandem repeat Analysis (MLVA). Results: With the exception of a single isolate which demonstrated intermediate susceptibility to streptomycin, all isolates were pansusceptible to the 14 antimicrobials tested. Thirty seven out of the 47 isolates (78.7%) exhibited an indistinguishable MLVA profile which included isolates from ready-to-eat food products, chicken, and human clinical isolates from stool, blood and exudate. Conclusions: The presence of highly related strains in both humans and raw chicken, and the failure to isolate the serovar from other foods, suggests that poultry is the main reservoir of S. Enteritidis in Mauritius and that the majority of human cases are associated with chicken consumption which originated from one major producer. Stool isolates were indistinguishable or closely related to blood and exudate isolates, indicating that, besides gastroenteritis, the same strain caused invasive infections. Control of S.Enteritidis by poultry breeders would lower the financial burden associated with morbidity in humans caused by this organism in Mauritius.

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 Epidemiology of a Salmonella enterica subsp. enterica Serovar Typhimurium Strain Associated with a Songbird Outbreak

2012 ◽  
Vol 78 (20) ◽  
pp. 7290-7298 ◽  
Author(s):  
Sonia M. Hernandez ◽  
Kevin Keel ◽  
Susan Sanchez ◽  
Eija Trees ◽  
Peter Gerner-Smidt ◽  
...  
Keyword(s):  
United States ◽  
Salmonella Enterica ◽  
Variable Number Tandem Repeat ◽  
Variable Number ◽  
Pfge Type ◽  
Eastern United States ◽  
Typing Method ◽  
Content Type ◽  
Typhimurium Strain ◽  
Serovar Typhimurium

ABSTRACTSalmonella entericasubsp.entericaserovar Typhimurium is responsible for the majority of salmonellosis cases worldwide. ThisSalmonellaserovar is also responsible for die-offs in songbird populations. In 2009, there was anS. Typhimurium epizootic reported in pine siskins in the eastern United States. At the time, there was also a human outbreak with this serovar that was associated with contaminated peanuts. As peanuts are also used in wild-bird food, it was hypothesized that the pine siskin epizootic was related to this human outbreak. A comparison of songbird and humanS. Typhimurium pulsed-field gel electrophoresis (PFGE) patterns revealed that the epizootic was attributed not to the peanut-associated strain but, rather, to a songbird strain first characterized from an American goldfinch in 1998. This sameS. Typhimurium strain (PFGE type A3) was also identified in the PulseNet USA database, accounting for 137 of 77,941 totalS. Typhimurium PFGE entries. A second molecular typing method, multiple-locus variable-number tandem-repeat analysis (MLVA), confirmed that the same strain was responsible for the pine siskin epizootic in the eastern United States but was distinct from a genetically related strain isolated from pine siskins in Minnesota. The pine siskin A3 strain was first encountered in May 2008 in an American goldfinch and later in a northern cardinal at the start of the pine siskin epizootic. MLVA also confirmed the clonal nature ofS. Typhimurium in songbirds and established that the pine siskin epizootic strain was unique to the finch family. For 2009, the distribution of PFGE type A3 in passerines and humans mirrored the highest population density of pine siskins for the East Coast.

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 Extensive Genetic Variability Linked to IS26Insertions in thefljBPromoter Region of Atypical Monophasic Variants of Salmonella enterica Serovar Typhimurium

2015 ◽  
Vol 81 (9) ◽  
pp. 3169-3175 ◽  
Author(s):  
Cécile Boland ◽  
Sophie Bertrand ◽  
Wesley Mattheus ◽  
Katelijne Dierick ◽  
Vicky Jasson ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Promoter Region ◽  
Variable Number Tandem Repeat ◽  
Genetic Alterations ◽  
Variable Number ◽  
Genomic Region ◽  
Phase 2 ◽  
Pathogenic Potential ◽  
Content Type ◽  
Serovar Typhimurium

ABSTRACTFifty-nine monophasicSalmonella entericaserovar Typhimurium isolates, collected in Belgium during the period from 2008 to 2011, have been serotyped as 4,[5]:i:− and shown to harbor anfljBcoding sequence. The genetic differences between these strains and phenotypically biphasicSalmonellaTyphimurium were analyzed through PCR and DNA sequencing. Genetic alterations in thefljBpromoter region affecting expression of the phase 2 flagellin were observed in 53 isolates. Other genetic events in the invertible region carrying thefljBpromoter were observed in 2 isolates. For the remaining 4 isolates, no molecular differences with a reference biphasicSalmonellaTyphimurium strain could be observed. Next-generation sequencing of one representative isolate affected in thefljBpromoter region revealed a 26-kb IS26composite transposon insertion along with a local genomic rearrangement. Several other IS26element-mediated alterations of this genomic region were observed. This group of monophasicSalmonellaTyphimurium isolates was genetically heterogeneous, as revealed by multilocus variable-number tandem-repeat analysis (MLVA), PCR, and sequencing. Pigs and pork represented a major source of such monophasic isolates in Belgium, as reported in other countries. Three out of 5 isolates of human origin presented genetic profiles identical to those of food isolates, demonstrating the pathogenic potential of the newly characterized variants and potential dissemination along the food chain. This study highlighted the key role played by IS26insertions in the loss of phase 2 flagellin expression and the subsequent generation of multiple monophasic variant lineages from biphasicSalmonellaTyphimurium ancestors.

scholarly journals Differences in Gene Content between Salmonella enterica Serovar Enteritidis Isolates and Comparison to Closely Related Serovars Gallinarum and Dublin

2005 ◽  
Vol 187 (18) ◽  
pp. 6545-6555 ◽  
Author(s):  
S. Porwollik ◽  
C. A. Santiviago ◽  
P. Cheng ◽  
L. Florea ◽  
M. McClelland
Keyword(s):  
Salmonella Enterica ◽  
Domestic Fowl ◽  
Phage Type ◽  
Gene Content ◽  
Comparative Genomic ◽  
Old Field ◽  
Salmonella Enterica Serovar Enteritidis ◽  
Cross Hybridization ◽  
Reference Collection ◽  
Almost All

ABSTRACT Salmonella enterica serovar Enteritidis is often transmitted into the human food supply through eggs of hens that appear healthy. This pathogen became far more prevalent in poultry following eradication of the fowl pathogen S. enterica serovar Gallinarum in the mid-20th century. To investigate whether changes in serovar Enteritidis gene content contributed to this increased prevalence, and to evaluate genetic heterogeneity within the serovar, comparative genomic hybridization was performed on eight 60-year-old and nineteen 10- to 20-year-old serovar Enteritidis strains from various hosts, using a Salmonella-specific microarray. Overall, almost all the serovar Enteritidis genomes were very similar to each other. Excluding two rare strains classified as serovar Enteritidis in the Salmonella reference collection B, only eleven regions of the serovar Enteritidis phage type 4 (PT4) chromosome (sequenced at the Sanger Center) were absent or divergent in any of the other serovar Enteritidis strains tested. The more recent isolates did not have consistent differences from 60-year-old field isolates, suggesting that no large genomic additions on a whole-gene scale were needed for serovar Enteritidis to become more prevalent in domestic fowl. Cross-hybridization of phage genes on the array with related genes in the examined genomes grouped the serovar Enteritidis isolates into two major lineages. Microarray comparisons of the sequenced serovar Enteritidis PT4 to isolates of the closely related serovars Dublin and Gallinarum (biovars Gallinarum and Pullorum) revealed several genomic areas that distinguished them from serovar Enteritidis and from each other. These differences in gene content could be useful in DNA-based typing and in understanding the different phenotypes of these related serovars.

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