Escherichia / Shigella
Escherichia / Shigella is a closely related pair of bacterial groups that are often reported together because sequencing struggles to tell them apart. They belong to the Proteobacteria phylum and are common, usually minor, members of the gut.
Many Escherichia strains are harmless everyday residents, but this group is watched because a persistently expanded share is sometimes discussed as a marker of an unsettled gut environment. Note that this grouping cannot, by itself, distinguish harmless strains from potentially problematic ones.
A higher Escherichia / Shigella share means this group takes up a larger part of your sample than usual, which is sometimes associated with a less settled gut. Because the reading is relative and cannot identify specific strains, a higher share is a signal to interpret in context, not a diagnosis of infection.
A low or modest share is typical and usually unremarkable, simply meaning this group forms a small portion of your sample.
General framing is that a small share is usual, while a persistently high share is worth discussing rather than acting on alone. This is evolving science that cannot confirm harmful strains from composition, so review a notably high share, especially with symptoms, together with a clinician.
Sources
Educational context only, not medical advice or a diagnosis. Reference ranges vary by lab, age and sex; always discuss your results with a clinician.