An apparent increase in the incidence of S. Brandenburg
in New Zealand, coupled with the
possibility that the virulence of the organism may also be changing, prompted
Three typing methods: macro-restriction fragment length polymorphism
using pulsed field gel electrophoresis (PFGE), plasmid
profiling and antimicrobial susceptibility
profiling were used to determine strain diversity amongst 115 recent and
historical isolates of
S. Brandenburg from both human cases and non-human sources.
Antimicrobial resistance was noted only in three isolates.
Plasmids of varying sizes were found
in 31 isolates. MRFLP analysis resulted in 13 different patterns. Combining
the three sets of
typing data yielded 24 composite types. Comparison of composite type, isolation
geographical location of case allowed the retrospective recognition of
seven potential clusters
during the 5-year study period. Composite types of 24 (80%) of the non-human
were indistinguishable from human isolates, suggesting that human infection
may be via a
number of vehicles.
Although not cost-effective for routine use on all salmonella isolates,
the methods used in
this study are an important adjunct to serotyping for discrimination within