Objective—To compare molecular typing methods
for the differentiation of Salmonella enterica serovar
Enteritidis phage type (PT) 4 isolates that allowed for
the determination of their genetic relatedness.
Sample Population—27 Salmonella Enteritidis PT 4
strains isolated in the United States and Europe.
Procedure—Several molecular typing methods were
performed to assess their ability to genetically differentiate
among Salmonella Enteritidis PT 4 isolates.
Results of pulse-field gel electrophoresis (PFGE),
repetitive polymerase chain reaction (PCR) assay, 16S
rRNA gene sequencing, random amplification of polymorphic
DNA (RAPD), PCR-restriction fragment
length polymorphism of 16S rRNA, and antimicrobial
susceptibility were evaluated.
Results—Compared with results for other techniques,
results for the RAPD typing method with the
RAPD1 primer reveal that it was the most discriminatory
fingerprinting technique, and it allowed us to
cluster Salmonella Enteritidis PT 4 isolates on the
basis of their genetic similarity.
Conclusions and Clinical Relevance—This study
revealed the value of RAPD with the RAPD1 primer as
a tool for epidemiologic investigations of Salmonella
Enteritidis PT 4. It can be used in conjunction with PFGE
and phage typing to determine the genetic relatedness
of Salmonella Enteritidis isolates involved in outbreaks
of disease. A reliable and highly discriminatory method
for epidemiologic investigations is critical to allow investigators
to identify the source of infections and consequently
prevent the spread of Salmonella Enteritidis
PT 4. ( Am J Vet Res 2004;65:538–543)