Volume 16, Number 11—November 2010
Research
Salmonella enterica Pulsed-Field Gel Electrophoresis Clusters, Minnesota, USA, 2001–2007
Joshua M. Rounds
, Craig W. Hedberg, Stephanie Meyer, David J. Boxrud, and Kirk E. Smith
, Craig W. Hedberg, Stephanie Meyer, David J. Boxrud, and Kirk E. SmithTable 3
Comparison of Salmonella enterica cluster investigation thresholds, Minnesota, USA, 2001–2007*
| Cluster investigation threshold | No. isolates represented in clusters | All Salmonella isolates, % (n = 3,803†) | Estimated interview time, h/y‡ | No. (%) outbreak clusters meeting threshold | Cluster investigation PPV |
|---|---|---|---|---|---|
| All clusters (n = 344) | 1,182 | 31 | 76 | 43 (100) | 13 |
| Clusters >3 cases (n = 152) | 778 | 20 | 50 | 35 (81) | 23 |
| Clusters >4 cases (n = 83) | 601 | 16 | 39 | 23 (53) | 28 |
| Clusters with a density of 0–14 d§ (n = 119) | 633 | 17 | 41 | 32 (74) | 27 |
| Clusters >4 cases or with a density of 0–7 d§ (n = 100) | 652 | 17 | 42 | 28 (65) | 28 |
*PPV, positive predictive value.
†A total of 215 isolates associated with excluded clusters were removed from study isolate total (n = 4,018).
‡Based on a 27-min median interview time per case-patient.
§Density defined as the number of days from receipt of first cluster case isolate to third case isolate received at the Minnesota Department of Health Public Health Laboratory.
