Table 2.
Summary of identified 0-, 5- and 10-SNP clusters of S. Enteritidis and S. Typhimurium by HPT (local), PHEC (regional) and national levels in England, April 2014–March 2015
| Serovar | SNP level | Geographical level | Total n of clusters (%)a | Total n of cases in clusters (%)a | Median no. of cases (range)a | Median duration of cluster in days (range) | N (%) of clusters with a SNP address common to another cluster | N (%) of clusters with household contactsb | N (%) of clusters with 75% known foreign travelc |
|---|---|---|---|---|---|---|---|---|---|
| Enteritidis | 0 | Local | 53/147 (36%) | 164/522 (31%) | 2 (2–25) | 3 (1–27) | 10/53 (19%) | 13/53 (25%) | 7/53 (13%) |
| Regional | 9/147 (6%) | 28/522 (5%) | 2 (2–8) | 4 (1–16) | 0 (–) | 1/9 (11%) | 2/9 (22%) | ||
| National | 85/147 (58%) | 330/522 (63%) | 2 (2–62) | 6 (1–30) | 28/85 (33%) | 4/85 (5%) | 22/85 (26%) | ||
| 5 | Local | 0 (–) | 0 (–) | – | – | – | – | – | |
| Regional | 2/40 (5%) | 14/602 (2%) | 7 (6–8) | 11.5 (9–14) | 0 (–) | 2/2 (100%) | 0 (–) | ||
| National | 38/40 (95%) | 588/602 (98%) | 7 (5–239) | 18.5 (4–134) | 31/38 (82%) | 9/38 (24%) | 3/38 (8%) | ||
| 10 | Local | 0 (–) | 0 (–) | – | – | – | – | – | |
| Regional | 0 (–) | 0 (–) | – | – | – | – | – | ||
| National | 16 (100%) | 505 (100%) | 14.5 (10–239) | 33.5 (16–134) | 11/16 (69%) | 6/16 (38%) | 0 (–) | ||
| Typhimurium | 0 | Local | 27/64 (42%) | 64/207 (31%) | 2 (2–11) | 3 (1–15) | 2/27 (7%) | 9/27 (33%) | 1/27 (4%) |
| Regional | 4/64 (6%) | 9/207 (4%) | 2 (2–3) | 7 (6–8) | 0 (–) | 0 (–) | 0 (–) | ||
| National | 33/64 (52%) | 134/207 (65%) | 2 (2–31) | 6 (1–27) | 4/33 (12%) | 2/33 (6%) | 4/33 (12%) | ||
| 5 | Local | 0 (–) | 0 (–) | – | – | – | – | – | |
| Regional | 1/11 (9%) | 5/117 (4%) | 5 (5–5) | 15 (15–15) | 0 (–) | 1/1 (100%) | 0 (–) | ||
| National | 10/11 (91%) | 112/117 (96%) | 7 (5–36) | 16 (1–29) | 0 (–) | 3/10 (30%) | 1/10 (10%) | ||
| 10 | Local | 0 (–) | 0 (–) | – | – | – | – | – | |
| Regional | 0 (–) | 0 (–) | – | – | – | – | – | ||
| National | 4/4 (100%) | 111 (100%) | 26.5 (15–43) | 32 (16–61) | 3/4 (75%) | 2/4 (50%) | 0 (–) |
a
SNP level column percentages.
b
Two or more of cases in a cluster had the same postcode.
c
75% or more of cases in a cluster had known travel history.