The role of aerobic respiration in the life cycle of Escherichia coli: Public health implications

The anaerobic intestinal setting of warm-blooded animals is considered E. coli’s main habi-tat. However E. coli transmission to new hosts requires the release of bacterial cells to an aerobic environment; we postulate that E. coli uses aerobic respiration to multiply in fecal matter during this phase of the cycle. To test this idea, we incubated fresh chicken fecal matter in aerobic and anaerobic settings and showed that E. coli counts increased signifi-cantly when fecal matter was incubated in the presence of oxygen. Our results suggest that aerobic growth in fecal matter outside of the host may be a crucial phase of E. coli’s natural cycle. This feature may extend to pathogenic members of the Enterobacteriaceae family.