TABLE 6.
Detection of R. solanacearum biovar 2 in natural river water samples at decreasing temperatures before and after up to 10 days of enrichment at 29 and 35°C in MWB. The positive enrichment of R. solanacearum was confirmed by growth on modified SMSA agar and DASI-ELISA
| Mo and yr of sampling | Water temp (°C) | Bacterial count (CFU/ml) on modified SMSA agar | No. of positive samples/no. of samples analyzed before enrichment
|
Enrichment temp (°C) | No. of positive enrichments/no. of enrichments analyzed
|
No. of MPN-positive samples/no. of samples | MPN range of R. solanacearum cells/100 ml | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Water vol sampled (ml)a
|
MPNd
|
||||||||||||
| DASI-ELISA | Co-PCR | 0.5b | 10c | 100c | 10 | 1 | 0.1 | ||||||
| September 2001 | 18 | 55-65 | 0/3 | 3/3 | 29 | 1/3 | 0/3 | 0/3 | ND | ND | ND | ND | ND |
| 35 | 3/3 | 3/3 | 3/3 | ND | ND | ND | ND | ND | |||||
| October 2001 | 14 | 5-25 | 0/3 | 3/3 | 29 | 3/3 | 0/3 | 0/3 | ND | ND | ND | ND | ND |
| 35 | 3/3 | 3/3 | 3/3 | ND | ND | ND | ND | ND | |||||
| November 2001 | 7-8 | 0-1 | 0/5 | 5/5 | 29 | 0/5 | 0/5 | 0/5 | 7/15 | 3/15 | 0/15 | 4/5 | <3-15 |
| 35 | 0/5 | 3/5 | 3/5 | 13/15 | 3/15 | 0/15 | 5/5 | 9-43 | |||||
| February 2002 | 6.4-6.9 | 0 | 0/5 | 5/5 | 29 | 0/5 | 0/5 | 0/5 | 0/15 | 0/15 | 0/15 | 0/5 | <3 |
| 35 | 0/5 | 0/5 | 0/5 | 2/15 | 0/15 | 0/15 | 1/5 | <3-9 | |||||
| March 2002 | 6.4-8.4 | 0 | 0/5 | 5/5 | 29 | 0/5 | 0/5 | 0/5 | 0/15 | 0/15 | 0/15 | 0/5 | <3 |
| 35 | 0/5 | 0/5 | 0/5 | 1/15 | 0/15 | 0/15 | 1/5 | <3-4 | |||||
a
Water samples were analyzed in duplicate.
b
Regular enrichment (1:10) in MWB.
c
Volume of filtered sample followed by enrichment in MWB.
d
Series of three tubes per sample volume. ND, not determined.