scholarly journals Phage type conversion in Salmonella enterica serotype Enteritidis caused by the introduction of a resistance plasmid of incompatibility group X (IncX)

1999 ◽  
Vol 122 (1) ◽  
pp. 19-22 ◽  
Author(s):  
D. J. BROWN ◽  
D. L. BAGGESEN ◽  
D. J. PLATT ◽  
J. E. OLSEN
Keyword(s):  
Salmonella Enterica ◽  
World Wide ◽  
Phage Type ◽  
Conjugative Plasmid ◽  
Type Conversion ◽  
Incompatibility Group ◽  
Phage Types ◽  
Resistance Plasmid ◽  
Salmonella Enterica Serotype Enteritidis

The plasmid pOG670, a 54 kb, conjugative plasmid that specifies resistance to ampicillin and kanamycin and belonging to the incompatibility group X (IncX), was transferred into 10 isolates of Salmonella enterica serotype Enteritidis belonging to 10 different phage types (PT1, 2, 3, 4, 8, 9, 9b, 10, 11 and 13). Acquisition of the plasmid by these strains did not result in the loss of any resident plasmids but resulted in phage type conversion in 8 of the 10 strains (PT1, 2, 4, 8, 9, 9b, 10 and 11). The observed changes in phage type were found to result from the loss of sensitivity to 3 of the 10 typing phages used (phages 3, 5 and 7). Where the conversion resulted in a change to a defined phage type, both the new and original PTs belonged to the same, previously described, evolutionary lines. Enteritidis PTs 1, 4 and 8, commonly associated with poultry world-wide, were converted to PTs 21, 6 and 13a respectively. The results indicate a different route for phage type conversion Enteritidis from others reported in the literature and, although IncX plasmids are not normally present in PT8 or PT13a, may suggest a possible mechanism/link connecting these phage types.

scholarly journals Dramatic shift in the epidemiology of Salmonella enterica serotype Enteritidis phage types in western Europe, 1998-2003 - results from the Enter-net international salmonella database

2004 ◽  
Vol 9 (11) ◽  
pp. 7-8 ◽  
Author(s):  
I. S.T. Fisher
Keyword(s):  
Public Health ◽  
Salmonella Enterica ◽  
Western Europe ◽  
Phage Type ◽  
Phage Typing ◽  
National Reference ◽  
Phage Types ◽  
Dramatic Shift ◽  
Salmonella Enterica Serotype Enteritidis

Salmonella enterica serotype Enteritidis is the predominant salmonella serovar identified by the Enter-net national reference laboratories in western Europe. As it is the most commonly recognised serotype, it is important that phage typing is carried out so that outbreaks can be recognised and confirmed, and trends in infections identifed. Data from the Enter-net salmonella database show that there has been a dramatic shift between phage types identified in Europe from 1998-2003. In 1998, the proportion of phage type (PT) 4 was 61.8%, making it the most frequently identified phage type in humans (21 630 cases), whereas by 2003 the proportion of PT4 had fallen to 32.1% (8794 cases) with other strains increasing, both in proportion and numbers. This paper identifies the emerging strains that are becoming more relevant in public health terms.

Multiplication in Egg Yolk and Survival in Egg Albumen of Salmonella enterica Serotype Enteritidis Strains of Phage Types 4, 8, 13a, and 14b

2001 ◽  
Vol 64 (6) ◽  
pp. 865-868 ◽  
Author(s):  
RICHARD K. GAST ◽  
PETER S. HOLT
Keyword(s):  
Salmonella Enterica ◽  
Salmonella Enteritidis ◽  
Egg Yolk ◽  
Phage Types ◽  
Egg Albumen ◽  
Range Of Values ◽  
Salmonella Enterica Serotype Enteritidis

Refrigeration of eggs is vital for restricting the multiplication of Salmonella enterica serotype Enteritidis contaminants, but differences between Salmonella Enteritidis strains or phage types in their survival and multiplication patterns in egg contents might influence the effectiveness of refrigeration standards. The present study compared the abilities of 12 Salmonella Enteritidis isolates of four phage types (4, 8, 13a, and 14b) to multiply rapidly in egg yolk and to survive for several days in egg albumen. The multiplication of very small numbers of Salmonella Enteritidis inoculated into yolk (approximately 101 CFU/ml) was monitored during 24 h of incubation at 25°C, and the survival of much larger numbers of Salmonella Enteritidis inoculated into albumen (approximately 105 CFU/ml) was similarly evaluated during the first 3 days of incubation at the same temperature. In yolk, the inoculated Salmonella Enteritidis strains multiplied to mean levels of approximately 103 CFU/ml after 6 h of incubation and 108 CFU/ml after 24 h. In albumen, mean levels of approximately 104 CFU/ml or more of Salmonella Enteritidis were maintained through 72 h. Although a few differences in multiplication and survival were observed between individual isolates, the overall range of values was relatively narrow, and no significant differences (P < 0.05) were evident among phage types.

scholarly journals Correlation of Phenotype with the Genotype of Egg-Contaminating Salmonella enterica Serovar Enteritidis

2005 ◽  
Vol 71 (8) ◽  
pp. 4388-4399 ◽  
Author(s):  
Cesar A. Morales ◽  
Steffen Porwollik ◽  
Jonathan G. Frye ◽  
Hailu Kinde ◽  
Michael McClelland ◽  
...  
Keyword(s):  
Microarray Analysis ◽  
Dna Sequences ◽  
Salmonella Enterica ◽  
Respiratory Activity ◽  
Phage Type ◽  
Field Isolate ◽  
Phenotype Microarray ◽  
Wild Type ◽  
Genomic Changes ◽  
Phage Types

ABSTRACT The genotype of Salmonella enterica serovar Enteritidis was correlated with the phenotype using DNA-DNA microarray hybridization, ribotyping, and Phenotype MicroArray analysis to compare three strains that differed in colony morphology and phage type. No DNA hybridization differences were found between two phage type 13A (PT13A) strains that varied in biofilm formation; however, the ribotype patterns were different. Both PT13A strains had DNA sequences similar to that of bacteriophage Fels2, whereas the PT4 genome to which they were compared, as well as a PT4 field isolate, had a DNA sequence with some similarity to the bacteriophage ST64b sequence. Phenotype MicroArray analysis indicated that the two PT13A strains and the PT4 field isolate had similar respiratory activity profiles at 37°C. However, the wild-type S. enterica serovar Enteritidis PT13A strain grew significantly better in 20% more of the 1,920 conditions tested when it was assayed at 25°C than the biofilm-forming PT13A strain grew. Statistical analysis of the respiratory activity suggested that S. enterica serovar Enteritidis PT4 had a temperature-influenced dimorphic metabolism which at 25°C somewhat resembled the profile of the biofilm-forming PT13A strain and that at 37°C the metabolism was nearly identical to that of the wild-type PT13A strain. Although it is possible that lysogenic bacteriophage alter the balance of phage types on a farm either by lytic competition or by altering the metabolic processes of the host cell in subtle ways, the different physiologies of the S. enterica serovar Enteritidis strains correlated most closely with minor, rather than major, genomic changes. These results strongly suggest that the pandemic of egg-associated human salmonellosis that came into prominence in the 1980s is primarily an example of bacterial adaptive radiation that affects the safety of the food supply.

scholarly journals Application of Fourier Transform Infrared Spectroscopy and Chemometrics for Differentiation of Salmonella enterica Serovar Enteritidis Phage Types

2010 ◽  
Vol 76 (11) ◽  
pp. 3538-3544 ◽  
Author(s):  
Ornella Preisner ◽  
Raquel Guiomar ◽  
Jorge Machado ◽  
Jos� Cardoso Menezes ◽  
Jo�o Almeida Lopes
Keyword(s):  
Fourier Transform ◽  
Ir Spectra ◽  
Salmonella Enterica ◽  
Intact Cell ◽  
Phage Type ◽  
Fourier Transform Infrared ◽  
Intact Cells ◽  
Phage Types ◽  
Ft Ir ◽  
Ir Analysis

ABSTRACT Fourier transform infrared (FT-IR) spectroscopy and chemometric techniques were used to discriminate five closely related Salmonella enterica serotype Enteritidis phage types, phage type 1 (PT1), PT1b, PT4b, PT6, and PT6a. Intact cells and outer membrane protein (OMP) extracts from bacterial cell membranes were subjected to FT-IR analysis in transmittance mode. Spectra were collected over a wavenumber range from 4,000 to 600 cm−1. Partial least-squares discriminant analysis (PLS-DA) was used to develop calibration models based on preprocessed FT-IR spectra. The analysis based on OMP extracts provided greater separation between the Salmonella Enteritidis PT1-PT1b, PT4b, and PT6-PT6a groups than the intact cell analysis. When these three phage type groups were considered, the method based on OMP extract FT-IR spectra was 100% accurate. Moreover, complementary local models that considered only the PT1-PT1b and PT6-PT6a groups were developed, and the level of discrimination increased. PT1 and PT1b isolates were differentiated successfully with the local model using the entire OMP extract spectrum (98.3% correct predictions), whereas the accuracy of discrimination between PT6 and PT6a isolates was 86.0%. Isolates belonging to different phage types (PT19, PT20, and PT21) were used with the model to test its robustness. For the first time it was demonstrated that FT-IR analysis of OMP extracts can be used for construction of robust models that allow fast and accurate discrimination of different Salmonella Enteritidis phage types.

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 Pulsed-Field Gel Electrophoresis Supports the Presence of Host-Adapted Salmonella enterica subsp. enterica Serovar Typhimurium Strains in the British Garden Bird Population

2011 ◽  
Vol 77 (22) ◽  
pp. 8139-8144 ◽  
Author(s):  
Becki Lawson ◽  
Laura A. Hughes ◽  
Tansy Peters ◽  
Elizabeth de Pinna ◽  
Shinto K. John ◽  
...  
Keyword(s):  
Gel Electrophoresis ◽  
Salmonella Enterica ◽  
Phage Type ◽  
Pulsed Field Gel Electrophoresis ◽  
Phage Typing ◽  
Molecular Technique ◽  
Content Type ◽  
Pulsed Field ◽  
Phage Types ◽  
Serovar Typhimurium

ABSTRACTSalmonellosis is a frequently diagnosed infectious disease of passerine birds in garden habitats within Great Britain with potential implications for human and domestic animal health. Postmortem examinations were performed on 1,477 garden bird carcasses of circa 50 species from England and Wales, 1999 to 2007 inclusive. Salmonellosis was confirmed in 263 adult birds of 10 passerine species in this 11-year longitudinal study. A subset of 124 fully biotypedSalmonella entericasubsp.entericaserovar Typhimurium isolates was examined using pulsed-field gel electrophoresis to investigate the hypothesis that these strains are host adapted and to determine whether this molecular technique offers greater resolution in understanding the epidemiology ofSalmonellaTyphimurium infection than phage typing alone. For the two most common phage types, definitive type (DT) 40 and DT56v, which together accounted for 97% (120/124) of isolates, pulsed-field gel electrophoresis groupings closely correlated with phage type with remarkably few exceptions. A high degree of genetic similarity (>90%) was observed within and between the two most common pulsed-field gel electrophoresis groups. No clustering or variation was found in the pulsed-field gel electrophoresis groupings by bird species, year, or geographical region beyond that revealed by phage typing. These findings support the hypothesis that there are currently two host-adaptedSalmonellaphage types,S. Typhimurium DT40 and DT56v, circulating widely in British garden birds and that the reservoir of infection is maintained within wild bird populations. Large-scale multilocus sequence typing studies are required to further investigate the epidemiology of this infection.

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