TABLE 1.
E. coli O157:H7 strains evaluated in this study
| Strain | Source | Description of isolate (reference) | Acid resistance categorya |
|---|---|---|---|
| ATCC 43895 | ATCCb | Ground beef isolate | Resistant |
| ATCC 43894 | ATCC | Human feces isolate | Resistant |
| ATCC 35150 | ATCC | Human feces isolate | Resistant |
| ATCC 43889 | ATCC | Human feces isolate | Adaptable |
| ATCC 43890 | ATCC | Human feces isolate | Sensitive |
| ATCC 43888 | ATCC | Human feces isolate | Sensitive |
| B6914-MS1 | Centers for Disease Control and Prevention, N. Strockbine | Human feces isolate | Sensitive |
| MARCS-1 | Roman L. Hruska U.S. Meat Animal Research Center culture collection | Streptomycin (250 μg/ml)-resistant B6914-MS1 isolate (19) | Sensitive |
| 2886-75 | E. coli Reference Center | Human feces isolate | Resistant |
| 86-24 | National Animal Disease Center, E. Nystrom | Human feces isolate (27) | Resistant |
| NADC 5570 | National Animal Disease Center, E. Nystrom | Streptomycin (100 μg/ml)-resistant E. coli O157:H7 86-24 isolate (27) | Resistant |
| NADC 4477 | National Animal Disease Center, T. Casey | Nalidixic acid (50 μg/ml)-resistant E. coli O157:H7 86-24 isolate (27) | Adaptable |
a
Based on survival and injury patterns of cells grown in TSB+G and TSB−G, following exposure to pH 2.5 for 6 h.
b
ATCC, American Type Culture Collection.