TABLE 4.
Mutation in barA and uvrY exhibits a reduction in mannose-resistant hemagglutination to chicken blood
| Strain | Genotype | Hemagglutination of 1% chicken erythrocytea [log2 (1/dilution)]
|
|
|---|---|---|---|
| Without 50 mM mannose | With 50 mM mannose | ||
| χ7122 | Wild type | 4 | 4 |
| AAEC072 | Δfim | 1 | <1 |
| AAEC072/p-Type-1 | Δfim/p-fimACDFGH clusterb | 5 | <1 |
| AAEC072/p-PapG1 | Δfim/p-pap clusterc | 4 | 4 |
| AAEC072/pSM1 | Δfim/p-barA | 4 | 2 |
| AAEC072/pSM2 | Δfim/p-uvrY | 5 | 5 |
| SM3000 | barA | 1 | 1 |
| SM3001 | uvrY | 1 | <1 |
| SM3002 | barA uvrY | 1 | <1 |
| SM3003 | barA/p-barA | 3 | 2 |
| SM3004 | uvrY/ p-uvrY | 4 | 3 |
The values are mean log2 of inverse dilution at which hemagglutination (HA) was observed with chicken blood. The standard deviation was <0.05 in all cases. The bacterial cultures were grown with two passages of 48 h each in static LB broth with appropriate antibiotics at 37oC to maximize type 1 fimbria expression. The assay was done on ice in duplicate in 96-well microtiter plates. Each bacterial culture was diluted twofold, before blood was added to study agglutination. The experiment was repeated twice with essentially similar results. The highest reciprocal of the dilution at which 50% of the erythrocytes sedimented to the bottom of the plate is taken as the HA titer.
Plasmid constitutively overexpressing type 1 fimbriae. It is a known positive control for the mannose-sensitive phenotype.
Plasmid overexpressing Pap fimbriae. It is a known positive control for the mannose-resistant phenotype.