TABLE 3.
Discrepancy analysis of isolates with discordant results based on the culture dependent algorithm
| Isolate | Original identification | Results of culture-dependent algorithm and motivation | Results of molecular algorithm | Predicted E. coli serotypea | Predicted Shigella O type | Presence/absence of genes for deviant resultsb |
|---|---|---|---|---|---|---|
| 505/58 | S. dysenteriae serotype 8 | EIEC, O untypeable; serologically S. dysenteriae 8, negative indole production against | S. dysenteriae non-O1/S. boydii/S. sonnei phase II/EIEC | O38: H26 | S. dysenteriae serotype 8 | tnaCAB cluster absent |
| 12698 | S. flexneri serotype 2b | EIEC, O untypeable; serological S. flexneri 2b, positive d-mannitol fermentation against | S. flexneri | O13:H14 | S. flexneri 2bc | mtlA, mtlD, and mtlR genes (mannitol operon) present |
| Z | S. flexneri serotype 3a | EIEC, O135; S. flexneri polyvalent positive, no conclusive serotype; antigenic formula B;6 | S. flexneri | O13/O135:H14 | S. flexneri 1cd | NA |
| 9355 | S. boydii serotype 9 | Provisional Shigella; serologically S. boydii 9, negative indole production against | S. dysenteriae non-O1/S. boydii/S. sonnei phase II/EIEC | No O-type genes, H14 | S. boydii serotype 9 | tnaCAB cluster present, tnaC and rrlB genes contain features essential for induction of tnaCAB cluster |
| F54157 | EIEC, O64 | S. sonnei, phase II; serologically and biochemically fit by repeat | S. dysenteriae non-O1/S. boydii/S. sonnei phase II/EIEC | O149:H45 | S. boydii, serotype 1; no S. sonnei, S. flexneri, or S. dysenteriae O-antigen genes present | NA |
| F54197 | EIEC, O64 | S. sonnei, phase II; serologically and biochemically fit by repeat | S. dysenteriae non-O1/S. boydii/S. sonnei phase II/EIEC | O149:H45 | S. boydii, serotype 1; no S. sonnei, S. flexneri or S. dysenteriae O-antigen genes present | NA |
| H57237 | EIEC, O+ | S. flexneri, serotype Yv | S. flexneri | O13:H14 | S. flexneri Yve | NA |
a
Using SerotypeFinder, Center for Genomic Epidemiology.
b
NA, not applicable.
c
wzx1-5, gtrII, and gtrX present.
d
wzx1-5, gtrI, gtrIc, and oac present.
e
wzx1-5 and lpt-O present.