TABLE 5.
Human E. coli isolates susceptible to lysogenic and/or lytic infection by Stx phages
| Strain | Phylogenetic group | φ933WΔtox or φ933W
|
φPT32Δtox or φPT32
|
||
|---|---|---|---|---|---|
| Lysogenya | Stx amplificationb | Lysogeny | Stx amplification | ||
| Human ECORc (O:H/core)d | |||||
| ECOR-1 (O144:H4/R2) | A | + | − | − | − |
| ECOR-4 (OR:H?/R4) | A | + | 256× | + | − |
| ECOR-6 (O173:H?/R3) | A | + | 8× | + | 32× |
| ECOR-9 (O167:H−/R3) | A | + | − | + | − |
| ECOR-10 (O6:H10/R2) | A | + | − | − | − |
| ECOR-12 (O?:H32/R2) | A | + | − | − | − |
| ECOR-13 (OR:H25/K-12) | A | + | 512× | + | 1,024× |
| ECOR-15 (O25:H30/R1) | A | + | − | − | − |
| ECOR-71 (OR:H19/R1) | B1 | + | − | − | − |
| ECOR-72 (O8:H30/R1) | B1 | + | − | − | − |
| ECOR-61 (O2:H4/R1) | B2 | + | − | − | − |
| ECOR-51 (O25:H1/R1) | B2 | − | − | − | 4× |
| ECOR-39 (O7:H−/R1) | D | + | − | − | − |
| ECOR-42 (O87:H26/R1) | E | + | − | − | − |
| ECOR-43 (O?:H18/R4) | E | + | − | − | − |
| Fecal isolatese | |||||
| FI-13 | A | + | − | − | − |
| FI-8 | B2 | + | − | − | − |
| FI-9 | B2 | − | − | + | − |
| FI-15 | B2 | + | − | − | 8× |
| FI-16 | B2 | + | − | − | − |
| FI-31 | B2 | − | − | − | 10× |
| FI-37 | B2 | − | − | − | 9× |
| PT-3 | A | + | − | − | − |
| PT-1 | B1 | + | − | + | − |
| PT-8 | B1 | + | − | − | − |
| PT-2 | B2 | + | − | − | − |
| PT-10a | B2 | + | − | − | − |
| PT-6 | D | − | − | + | − |
| PT-12 | D | + | − | − | − |
Lysogeny was assessed by acquisition of GFP DNA from colonies selected for chloramphenicol resistance following infection with φ933WΔtox or φPT32Δtox. +, lysogens detected; −, no lysogens detected.
Stx, a late gene product, was monitored as evidence of lytic infection following incubation with phage φ933W or φPT32. Fold increase over Stx present in initial phage inoculum is reported when significantly elevated over control values (P < 0.05). −, toxin amplification not detected.
Fifteen of 40 human ECOR isolates tested positive for lysogeny or lytic infection (negative strains or results are not reported).
Serotyping and determination of LPS core type as reported by Amor et al. (2a). OR, rough LPS; ?, unidentifiable.
Seven of 29 FI isolates and 7 of 12 PT isolates tested positive for lysogeny or lytic infection.