Non-Human Salmonella Isolates, 2013 No. 8, August

The Enteric Reference Laboratory confirmed 181 non-human Salmonella isolates in August 2013 compared with 146 August 2012.

There was an increase in the number of Ovine S. Brandenburg isolates (22 in 2012 versus 37 in 2013) this month. Occurrence of S. Brandenburg infection in humans is a seasonal phenomenon in the southern half of the South Island (Baker et al Epidemiol Infect 2007; 135:76-83) and is often linked with occurrence of the serotype in livestock. Salmonella Brandenburg has caused periodic epidemics of disease in sheep flocks in Otago and Southland since 1997.
See also: http://www.stuff.co.nz/business/farming/sheep/9090477/Bacterial-outbreak-killing-South-Island-sheep

An increase in the following serotypes was also confirmed this month:·

• Agona (1 in 2012 versus 9 in 2013)
• Montevideo (0 in 2012 versus 9 in 2013)
• Saintpaul (0 in 2012 versus 5 in 2013)
• Typhimurium phage type 1 (4 in 2012 versus 11 in 2013)
• Typhimurium phage type 101 (4 in 2012 versus 10 in 2013)
• Typhimurium phage type 56 variant (3 in 2012 versus 22 in 2013)

There was a decrease in Typhimurium phage type 12a (11 in 2012 versus 1 in 2013)

S. Typhimurium phage type 56 variant was previously known (prior to July 2013) as RDNC-May 06. Further characterisation by the Salmonella Reference Unit at Colindale (Public Health England) identified this phage type to be a 56 variant.