Phage conversion in<i>Salmonella enterica</i>serotype Enteritidis: implications for epidemiology

Rankin, Shelley C.; Platt, D. J.

doi:10.1017/s0950268800057897

Cited by 52 publications

(40 citation statements)

References 31 publications

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“…However, this system presents some limitations. Not all organisms can be ascribed to recognized types, phage conversions are possible (3,26), and the method requires access to special reagents available only in reference laboratories. Ribotype data from our study suggest a close relationship between PT1, PT4, and PT7.…”

Section: Discussionmentioning

confidence: 99%

Diversity of Strains of Salmonella enterica Serotype Enteritidis from English Poultry Farms Assessed by Multiple Genetic Fingerprinting

et al. 2001

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Reliable and sufficiently discriminative methods are needed for differentiating individual strains of Salmonella enterica serotype Enteritidis beyond the phenotypic level; however, a consensus has not been reached as to which molecular method is best suited for this purpose. In addition, data are lacking on the molecular fingerprinting of serotype Enteritidis from poultry environments in the United Kingdom. This study evaluated the combined use of classical methods (phage typing) with three well-established molecular methods (ribotyping, macrorestriction analysis of genomic DNA, and plasmid profiling) in the assessment of diversity within 104 isolates of serotype Enteritidis from eight unaffiliated poultry farms in England. The most sensitive technique for identifying polymorphism was PstI-SphI ribotyping, distinguishing a total of 22 patterns, 10 of which were found among phage type 4 isolates. Pulsed-field gel electrophoresis of XbaI-digested genomic DNA segregated the isolates into only six types with minor differences between them. In addition, 14 plasmid profiles were found among this population. When all of the typing methods were combined, 54 types of strains were differentiated, and most of the poultry farms presented a variety of strains, which suggests that serotype Enteritidis organisms representing different genomic groups are circulating in England. In conclusion, geographical and animal origins of Salmonella serotype Enteritidis isolates may have a considerable influence on selecting the best typing strategy for individual programs, and a single method cannot be relied on for discriminating between strains.

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Section: Discussionmentioning

confidence: 99%

Diversity of Strains of Salmonella enterica Serotype Enteritidis from English Poultry Farms Assessed by Multiple Genetic Fingerprinting

et al. 2001

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“…PT 4b is a very rare group (50), and to the best of our knowledge it has not been previously reported to have been isolated from eggs. Classification into PT 4b is due to the presence of an extra phage receptor (52), and PT variation during circulation in the field has been reported for Salmonella serovar Enteritidis (2,41). The results could suggest that the absence of such a receptor may represent an advantage for transmission of the strain to humans, and in this regard, it would be interesting to conduct further genetic analyses or virulence assays with these otherwise identical strains.…”

Section: Fig 1 Examples Of Amplification Patterns Obtained With Primentioning

confidence: 91%

Random Amplified Polymorphic DNA and Phenotyping Analysis of Salmonella enterica Serovar Enteritidis Isolates Collected from Humans and Poultry in Uruguay from 1995 to 2002

Betancor

Schelotto²,

Martinez³

et al. 2004

J Clin Microbiol

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Molecular and phenotyping techniques were applied to study Salmonella enterica serovar Enteritidis strains both from human cases of infection and of avian origin isolated in Uruguay from 1995 to 2002. A group of 62 isolates was subjected to random amplified polymorphic DNA (RAPD) assay and analysis of antibiotic resistance patterns. Twenty-one of these strains were further characterized by phage typing and analysis of their protein expression profiles. RAPD fingerprinting with five different primers discriminated 10 different genetic profiles. Of the 62 strains tested, 48 had a single major genetic profile, whereas the other nine profiles were evenly distributed among the other strains. The genetic diversity was greater among strains of animal origin than among isolates of human origin. Comparative examination of the results obtained by RAPD analysis and phenotypic analysis and by strain source provided evidence of the reliable discriminatory power of RAPD analysis in our study. Six avian isolates with antibiotic resistance were detected: two were nalidixic acid resistant and four had a particular ␤-lactam resistance pattern. The last four isolates all had the same unusual phage type (phage type 4b); however, RAPD analysis differentiated them into two groups. Two isolates with unique RAPD profiles were recovered from distinct human cases, suggesting that the technique differentiates unrelated strains. Overall, the results show the existence of a predominant genetic type that is present in poultry and that is transmitted to humans. There are also several other genotypes, but only a few of them could be recovered from human sources, suggesting the existence of different pathogenic traits among strains circulating in the country.

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“…Moredifferent regions of Italy in the same period further over, seven of eight outbreaks from which different confirmed the usefulness of this molecular method to phage types had been identified proved to be related to a single bacterial strain. Phage type heterogeneity observed in such instances presumably depends on phage conversion phenomena [9].…”

Section: Discussionmentioning

confidence: 99%

“…On this basis, phage typing alone appears to be inadequate for monitoring the spread of Enteritidis. Furthermore, changes in phage type occur by acquisition of a plasmid [7], loss of lipopolysaccharide [8] or phage conversion [9]. Likewise, interconversion of PT4 and PT8 has been observed [9], even though epidemiological data confirm their stability under field conditions.…”

Section: Introductionmentioning

confidence: 99%

Epidemiological analysis of strains of Salmonella enterica serotype Enteritidis from foodborne outbreaks occurring in Italy, 1980-1994

Nastasi¹,

Mammina²,

Fantasia³

et al. 1997

Journal of Medical Microbiology

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Polymerase chain reaction (PCR-) ribotyping was performed on 243 strains of Salmonella enterica serotype Enteritidis isolated during the years 1980-1994 from 58 foodborne outbreaks occurring in different regions of Italy. The majority (37) of the outbreaks were attributed to phage type (PT) 4, followed by PT1 (seven outbreaks); the latter was identified in 1993 in Italy in epidemic strains of Enteritidis. In eight cases more than one phage type was recognised from a single event. Nine PCR-ribotypes (PCR-RTs) were detected, with a strong prevalence of PCR-RTs f7 and e5 (23 and 21 outbreaks, respectively). In two instances two distinct PCR-RTs were identified within strains from a single outbreak. All but one of the PT1 outbreaks were caused by PCR-RT fl, whereas PT4 outbreaks could be subdivided into six subsets. Clustering of isolates was consistent with data obtained from epidemiological investigations. PCRribotyping proved to be an effective and reliable tool for subtyping isolates of Enteritidis belonging to the most frequent phage types. Nevertheless, in terms of laboratory expertise and lack of inter-laboratory standardisation, this typing technique is best suited for reference laboratories.

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Phage conversion inSalmonella entericaserotype Enteritidis: implications for epidemiology

Cited by 52 publications

References 31 publications

Diversity of Strains of Salmonella enterica Serotype Enteritidis from English Poultry Farms Assessed by Multiple Genetic Fingerprinting

Diversity of Strains of Salmonella enterica Serotype Enteritidis from English Poultry Farms Assessed by Multiple Genetic Fingerprinting

Random Amplified Polymorphic DNA and Phenotyping Analysis of Salmonella enterica Serovar Enteritidis Isolates Collected from Humans and Poultry in Uruguay from 1995 to 2002

Epidemiological analysis of strains of Salmonella enterica serotype Enteritidis from foodborne outbreaks occurring in Italy, 1980-1994

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