Enterobacteriaceae, more specifically Escherichia coli and Klebsiella pneumoniae, are the bacteria most often responsible for neonatal infections in low-income countries. Infections caused by multidrug-resistant Enterobacteriaceae: Extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E), are more often associated with an unfavorable outcome of the infection.

Enterobacteriaceae colonize the digestive tract which is the first step in developing a potential infection. Very few studies have been carried out at the community level. Colonization of the mother with ESBL-E is generally considered to be a major route of acquisition. The carrying of ESBL-E by other family members and other potential sources of transmission (food, objects and surfaces in contact with the newborn) have never been documented.

In addition, with a view to offering an intervention adapted to the local context, the local cultural determinants which govern the interactions of the newborn with his environment are important to understand.

This is a single-center prospective cohort of all members living in the same household in which a newborn baby has just been born.

The study consists to:

• recruit a cohort of all members of 60 households in which a newborn has just been born
• carry out semi-structured interviews and direct participant observation.

This study is divided in two parts :

• the epidemiological part : the documentation of colonization by E-ESBL by sampling the stools of the newborn, of all members of the household, and sampling of food given to the child, from surfaces in contact with it.
• the anthropological part : Semi-structured interviews with key people in the structuring of the social and family environment of the newborn and participant direct observation of households.

Inclusion Criteria:

1. For the epidemiological study :

   All members of 60 households in which a newborn baby has just been born

   Inclusion criteria for the mother at the time of childbirth, pregnant woman :

   _ having a monofetal pregnancy

   • residing regularly in the study area OR planning to reside in the study area during the study period;
   • having been informed of the research and collection of biological samples on herself and her newborn;
   • having given its agreement to carry out the research and the associated collection of biological samples, and;
   • having signed the informed consent (or its witness if applicable).

   Inclusion criteria for the live newborn at the time of childbirth, new born :

   • living after childbirth;
   • whose parents or legal representatives present:
   • reside regularly in the study area or plan to reside in the study area during the study period;
   • were informed of the research and the associated collection of biological samples on their newborn;
   • have given their agreement to carry out the research and the associated collection of biological samples,

   Inclusion criteria for the household member, resident:

   • from the same household as the mother-child (ren) couple included
   • Residing at least 4 nights per week in this home
   • Having given its agreement to carry out the research and the associated collection of biological samples,
   • and having signed the consent of the study (or its witness, or its legal representative if applicable)

2. for the anthropological study with interviews : 16 homes will be selected from among the 60 homes included: 8 homes in which the child has not acquired an ESBL-E during the entire follow-up and 8 homes in which the child has acquired an ESBL-E at least once during its follow-up. Among these households, interviews will be carried out with: 16 mothers or first responsible for the child in the absence of the mother 4 people with a mothering role on the child (grandmother, aunts ...) 4 minors in the families to observe 4 fathers or father figures in families to observe

   Also, interviews will be done with:

   Health actors: medical (1 midwife and 1 neighborhood doctor) and traditional (1 matron and 1 traditional practitioner from the neighborhood), 1 community health worker 1 neighborhood chief

   Inclusion criteria for semi-structured interviews :

   • people responding to the structuring functions of the child's social and family environment
   • Having given its agreement to carry out the research,
   • and having signed the consent of the study (or its witness, or its legal representative if applicable)

   For health workers and district managers, inclusion criteria for semi-structured interviews :

   • people responding to the targeted functions
   • working in the district of homes included
   • Having given its agreement to carry out the research,
   • and having signed the consent of the study (or its witness, or its legal representative if applicable)

3. For the anthropological study with observations 4 households in total among the 16 initially selected for the interviews: 2 households in which the child did not acquire ESBL-E during all the follow-up and 2 households in which the child acquired at least once an BLSE-E during his follow-up Inclusion criteria for participating direct observations

   • Residents of the same household as the mother-child (ren) couple included
   • having agreed to participate in the study
   • Having given its agreement to carry out the research,
   • and having signed the consent of the study (or its witness, or its legal representative if applicable)

Exclusion Criteria:

1. For the epidemiological part:

   • Pregnant woman: non-monofetal pregnancy
   • Newborn: died during childbirth
   • Household resident: None

2. and 3) For the anthropological part: • Semi-structured interview:

For household members:

• not responding to the structural family and social functions of the child's environment For health workers and district managers

• people not meeting the targeted functions

• not practicing in the district of homes included

  • Participant direct observation:

• Not living in the same household as the mother-child couple included

1. epidemiological study

   All members of 60 households in which a newborn baby has just been born

2. anthropological study with interviews

16 homes will be selected from among the 60 homes included: 8 homes (no ESBL-E) and 8 homes (ESBL-E). Interviews will be carried out with: 16 mothers 4 people with a mothering role on the child 4 minors in the families 4 fathers

Also, interviews will be done with:

Health actors: medical and traditional, 1 community health worker

1 neighborhood chief

3) anthropological study with observations 4 households in total among the 16 initially selected for the interviews: 2 households (no ESBL-E) and 2 households (ESBL-E)