Human Salmonella isolates, 2019 No.10, October

The number of isolates (n=118) confirmed this month showed an increase in comparison to the number of isolates confirmed in October 2018 (n=95). Salmonella Enteritidis phage type 28 (11% in October 2019 vs 0% in October 2018) was the most common serotype confirmed this month. Salmonella Wagenia was confirmed for the first time in New Zealand this month.

In the last week of this month phage typing was phased out, Whole Genome Sequencing (WGS) was introduced, and from this point a Multi Locus Sequence Type (MLST) will be reported as a Sequence Type (ST) number instead for Serotypes Enteritidis, Typhi, and Typhimurium. Multi Locus Sequence Type (MLST or ST) is instead now included in line with standard international practice.

An outbreak of rare Salmonella Enteritidis phage type 28 infections linked to a SkyCity restaurant, Auckland - update (Source: EpiSurv 13 November 2019 1445 hours, Auckland Regional Public Health Service (ARPHS), Regional Public Health, Ministry for Primary Industries (MPI), ESR Enteric Reference Laboratory)

• From 13 to 29 October 2019 there have been 13 cases of Salmonella Enteritidis phage type 28 infection linked to an outbreak at Gusto at the Grand restaurant, SkyCity Auckland between 11 and 22 October.
• Four additional cases are currently under investigation, including one probable case in Australia. The Australian case stayed at the SkyCity hotel and ate at the Gusto restaurant between 4 and 11 October and has tested positive for Salmonella Enteritidis infection. Whole genome sequencing will be carried out in Australia to determine if this case was infected with the outbreak strain.
• Epidemiological analysis of case questionnaires identified a statistically significant association with salted caramel semifreddo (OR 7.33 95%CI 1.63-32.92) and panna cotta (OR 6.00 95% CI 1.44-24.92) desserts served at the Gusto at the Grand restaurant.
• Results of testing of vanilla pods used in the panna cotta dessert were negative for Salmonella.
• No new illnesses have been reported since the restaurant reopened on 05 November 2019.