A pulsed field gel electrophoresis (PFGE) study that suggests a major world-wide clone of Salmonella enterica serovar Enteritidis

Salmonella enterica subsp. enterica serovar Enteritidis is a major cause of food-borne salmonellosis in the United States. Two major food vehicles for S. Enteritidis are contaminated eggs and chicken meat. Improved subtyping methods are needed to accurately track specific strains of S. Enteritidis related to human salmonellosis throughout the chicken and egg food system. A sequence typing scheme based on virulence genes (fimH and sseL) and clustered regularly interspaced short palindromic repeats (CRISPRs)-CRISPR-including multi-virulence-locus sequence typing (designated CRISPR-MVLST)-was used to characterize 35 human clinical isolates, 46 chicken isolates, 24 egg isolates, and 63 hen house environment isolates of S. Enteritidis. A total of 27 sequence types (STs) were identified among the 167 isolates. CRISPR-MVLST identified three persistent and predominate STs circulating among U.S. human clinical isolates and chicken, egg, and hen house environmental isolates in Pennsylvania, and an ST that was found only in eggs and humans. It also identified a potential environment-specific sequence type. Moreover, cluster analysis based on fimH and sseL identified a number of clusters, of which several were found in more than one outbreak, as well as 11 singletons. Further research is needed to determine if CRISPR-MVLST might help identify the ecological origins of S. Enteritidis strains that contaminate chickens and eggs.

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“…3). The existence of major clonal groups of S. Enteritidis in humans and poultry was also observed previously using PFGE (4,33).…”

Section: Discussionsupporting

confidence: 79%

Subtyping Salmonella enterica Serovar Enteritidis Isolates from Different Sources by Using Sequence Typing Based on Virulence Genes and Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs)

Liu

Kariyawasam

Jayarao

et al. 2011

Appl Environ Microbiol

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“…It has also been reported that the genotypes of ST isolates from humans and animals were closely related in some cases (Tsen et al, 2002). Pang et al (2007) reported that PFGE subtypes of S. Enteritidis showed about 75% homogeneity regardless of the geographic area and host source of the isolates. It was reported that PFGE patterns generated from the XbaI enzyme were very similar among S. Enteritidis strains (Kang et al, 2009;Laconcha et al, 2000;Woo, 2005).…”

Section: Discussionmentioning

confidence: 93%

“…The differences in the genotypes of the ST isolates tested may be due to their different isolation times, areas and origins. They may also be due to the acquisition of mobile genes, either temperate phages or plasmids, and new sets of genes acquired by transduction, transposition, or transformation (Pang et al, 2007). However, previous reports have suggested that ST infections in humans are largely due to the consumption of contaminated pork and beef (Gudmundsdottir et al, 2003).…”

Section: Discussionmentioning

confidence: 99%

Genotyping, Phage Typing, and Antimicrobial Resistance of Salmonella Typhimurium Isolated from Pigs, Cattle, and Humans

Ju¹,

Kang²,

Jung³

et al. 2011

Korean Journal for Food Science of Animal Resources

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Salmonella enterica serovar Typhimurium (ST) is one of the most common serovars isolated from humans and animals. It has been suggested that ST infections in Koreans are largely due to the consumption of contaminated pork and beef. To investigate the genotypes, phage types, and antimicrobial resistance patterns for ST isolates of different origins, a total of 70 ST strains, including 19 isolates from humans, 44 isolates from pigs, and 6 isolates from cattle, were analyzed using pulsedfield gel electrophoresis (PFGE), phage typing, and antimicrobial susceptibility tests. Forty-three distinct PFGE patterns were generated from 70 ST isolates, which were grouped into 14 PFGE groups (from A to N) at the level of 75% similarity. The most prevalent group was the A (A1-A17 subtypes) group, encompassing 54.5% (38/70) of ST isolates. ST isolates from pigs and cattle mostly belong to groups A and L, whereas ST isolates from humans mostly belong to groups F and C. Antimicrobial susceptibility tests using 11 antimicrobial agents showed that resistance to tetracycline (TE) (81.4%) was highly prevalent, followed by streptomycin (S) (64.3%) and nalidixic acid (NA) (31.4%) resistance. A total of seventeen antimicrobial resistance patterns were observed. Only 8.6% of isolates, including a reference strain, were susceptible to all antimicrobial agents tested. The most prevalent resistance pattern was TE-S (37.1%), which was seen in 66.6% of bovine, 40.8% of swine and 21.1% of human isolates. Three ST isolates from humans (15.9%) showed resistance to 7-8 antimicrobials. The most predominant phage type (PT) was U302 (64.3%), followed by DT170 (10.0%). PFGE types did not coincide with antimicrobial resistance patterns and phage types; therefore, the combination of those types allowed for further differentiation between tested ST isolates.

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“…Pulsed-field gel electrophoresis (PFGE) is a highly reproducible and discriminating tool for the molecular subtyping of bacteria, which is often recommended as a reference method in outbreak investigations. It has been successfully applied to a broad range of different Gram-negative and Gram-positive bacteria [4][5][6][7][8][9][10][11]. Bacterial subtyping by PFGE relies on the determination of the relationship between different isolates by comparing their DNA macrorestriction patterns [12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Cost-effective procedure for Streptococcus pyogenes immobilized DNA preparation and miniPFGE subtyping

López

Suárez

Niubó

et al. 2015

J Infect Dev Ctries

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Introduction: Group A streptococci (GAS) is responsible of several human diseases ranging from mild infection to severe invasive toxinmediated disease and post-infectious sequelae. Accordingly, a GAS surveillance program based on molecular techniques is advisable for its epidemiological control. Pulsed-field gel electrophoresis (PFGE) is the gold standard for GAS molecular subtyping, but a major disadvantage is the length of the procedure, which takes 1-3days of work, minimum. The aim of this study was to develop a rapid and cost-effective procedure for PFGE subtyping of GAS isolates. Methodology: Different incubation times of GAS, immobilized in agarose miniplugs, in solutions containing lysozyme and/or mutanolysine followed by solutions with urea instead of proteinase K, were assayed. DNA was restricted with SmaI and the fingerprints were obtained in clamped homogeneous electric field (CHEF) chambers and minichambers. The modified procedure was used to subtype 22 GAS isolates. Results: Intact DNA molecules of GAS immobilized in agarose miniplugs were prepared incubating the cells, in situ, with a solution containing lysozyme for 4hours, followed by the incubation in a non-enzymatic solution with urea for 2hours. SmaIDNA macrorestriction fragments were well resolved in 5hours and 14minutes by electrophoresis in a CHEF minichamber at 10V/cm. This procedure for GAS DNA preparation was useful for fingerprinting GAS strains in the format of CHEFMapper (BioRad). Conclusions: The procedure took 13 hours for GAS strains subtyping. Both sample preparation and electrophoresis in CHEF minichamber represent an economic alternative for performing massive epidemiological studies of this human pathogen.

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A pulsed field gel electrophoresis (PFGE) study that suggests a major world-wide clone of Salmonella enterica serovar Enteritidis

Cited by 38 publications

References 22 publications

Subtyping Salmonella enterica Serovar Enteritidis Isolates from Different Sources by Using Sequence Typing Based on Virulence Genes and Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs)

Subtyping Salmonella enterica Serovar Enteritidis Isolates from Different Sources by Using Sequence Typing Based on Virulence Genes and Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs)

Genotyping, Phage Typing, and Antimicrobial Resistance of Salmonella Typhimurium Isolated from Pigs, Cattle, and Humans

Cost-effective procedure for Streptococcus pyogenes immobilized DNA preparation and miniPFGE subtyping

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