Volume 9, Number 6—June 2003
Research
Molecular Subtyping to Detect Human Listeriosis Clusters
Table 2
Comparison of statistically significant temporal listeriosis clusters stratified by subtyping technique used to detect and confirm each cluster
Clusters | Cluster definition | No. of clusters | No. of cases (%)a |
---|---|---|---|
1. Clusters detected by ribotype or PFGE |
Ribotype clusters or PFGE clusters detected by using the scan statistic (p<0.05) |
9 |
41 (31) |
2. Ribotype clusters |
Indistinguishable ribotype pattern clusters detected by the scan statistic (p<0.05) |
6 |
31 (24) |
2a. Ribotype clusters supported by PFGE |
Ribotype clusters, containing closely related PFGE types (<3 bands difference) |
6 |
26 (20) |
3. PFGE clusters |
Indistinguishable PFGE patterns detected by the scan statistic (p<0.05) |
8 |
31 (24) |
3a. PFGE clusters supported by ribotype |
PFGE clusters, which contained identical ribotype patterns |
8 |
30 (23) |
4. Clusters supported by ribotype and PFGE |
Clusters detected as 2a and 3a |
5 |
23 (18) |
5. Epidemiologically linked ribotype or PFGE clusters | Clusters detected by ribotype, PFGE, or both and supported by epidemiologic data | 2 | 17 (13) |
aBased on total sample population of 131 isolates; PFGE, pulsed-field gel electrophoresis.