Inclusion Criteria:

• Residents present on the day of sampling (D0 or D+1) in a facility selected during randomization, without criteria regarding length of stay in the facility, and whose health status on the day of the survey permits it;
• Residents who, based on clinical criteria (including an MMSE greater than or equal to 20), are deemed by the nursing home team to be able to understand the issues of the study and to express an informed non-opposition; OR Residents who the nursing home team considers unable to express an informed non-objection but who have a legal representative, a trusted person, or a loved one capable of understanding the information and expressing an informed non-objection.

Residents may be included regardless of the presence of infection, diarrheal stools, antibiotic use or any other treatment, or health status.

Participants in this study may participate in other research projects concurrently.

Exclusion Criteria: Health and medico-social facilities not considered nursing homes (e.g., FAM, MAS, etc.);

• Residents whose health status is incompatible with performing the procedure on the day of the survey (e.g., end-of-life with comfort care);
• Residents with a Mini Mental State Examination (MMSE) score of less than or equal to 20, or without an MMSE score but who, according to nursing home professionals, are unable to provide an informed non-objection and who do not have a legal representative, trusted person, or relative capable of receiving information and providing an informed non-objection;
• Residents, regardless of their MMSE score, who refuse to have the sample taken on the day of the survey even if their legal repre