Publications by authors named "Jean Marc Collard"

Article Synopsis
  • A specific type of regulatory B cells in newborns (nBreg) uses IL-10 to limit the production of IgM antibodies, which helps control the immune response after initial activation.
  • *By analyzing these nBreg cells in fetal and neonatal intestines, researchers identified their antibody repertoire and demonstrated that they produce antibodies that react to various bacteria in the early microbiota.
  • *This study suggests that nBreg populations are crucial for shaping the microbiome during early life by influencing bacterial diversity and metabolism.*
View Article and Find Full Text PDF

Autophagy receptor NDP52 triggers bacterial autophagy against infection. However, the ability of NDP52 to protect against viral infection has not been established. We show that NDP52 binds to envelope proteins of hepatitis B virus (HBV) and triggers a degradation process that promotes HBV clearance.

View Article and Find Full Text PDF

Background: Few studies on neonatal severe bacterial infection are available in LMICs. Data are needed in these countries to prioritize interventions and decrease neonatal infections which are a primary cause of neonatal mortality. The BIRDY project (Bacterial Infections and Antimicrobial Drug Resistant among Young Children) was initially conducted in Madagascar, Senegal and Cambodia (BIRDY 1, 2012-2018), and continued in Madagascar only (BIRDY 2, 2018-2021).

View Article and Find Full Text PDF

Eukaryotes have historically been studied as parasites, but recent evidence suggests they may be indicators of a healthy gut ecosystem. Here, we describe the eukaryome along the gastrointestinal tract of children aged 2-5 years and test for associations with clinical factors such as anaemia, intestinal inflammation, chronic undernutrition, and age. Children were enrolled from December 2016 to May 2018 in Bangui, Central African Republic and Antananarivo, Madagascar.

View Article and Find Full Text PDF
Article Synopsis
  • Environmental Enteric Dysfunction (EED) is linked to stunting in children from poor settings, and intestinal infections play a role in its development.
  • A study involving 464 children aged 2 to 5 found that over half had at least one viral infection, but these infections did not correlate with the children's growth status.
  • The research did not establish a direct connection between stunting and viral infections, though certain factors like poor food quality and maternal obesity were noted as risk factors for viral carriage.
View Article and Find Full Text PDF

The human gut bacteriome is believed to have pivotal influences on human health and disease while the particular roles associated with the gut phageome have not been fully characterized yet with few exceptions. It is argued that gut microbiota can have a potential role in autism spectrum disorders (ASD). The public microbiota database of ASD and typically developing (TD) Chinese individuals were analyzed for phage protein-coding units (pPCU) to find any link between the phageome and ASD.

View Article and Find Full Text PDF

Background: ESBL-producing Escherichia coli (ESBL-Ec) is considered a key indicator for antimicrobial resistance (AMR) epidemiological surveillance in animal, human and environment compartments. There is likelihood of ESBL-Ec animal-human transmission but proof of cross-compartment transmission is still unclear.

Objectives: To characterize ESBL-Ec genetic similarity in various compartments (humans, animals and environment) from a rural area of Madagascar.

View Article and Find Full Text PDF

Background: Antibiotic resistance is a global public health issue, particularly in low- and middle-income countries (LMICs), where antibiotics required to treat resistant infections are not affordable. LMICs also bear a disproportionately high burden of bacterial diseases, particularly among children, and resistance jeopardizes progress made in these areas. Although outpatient antibiotic use is a major driver of antibiotic resistance, data on inappropriate antibiotic prescribing in LMICs are scarce at the community level, where the majority of prescribing occurs.

View Article and Find Full Text PDF

Background: The exact timing, causes, and circumstances of stillbirth and neonatal mortality in low- and middle-income countries (LMICs) remain poorly described, especially for antenatal stillbirths and deaths occurring at home. We aimed to provide reliable estimates of the incidence of stillbirth and neonatal death in three LMICs (Madagascar, Cambodia and Senegal) and to identify their main causes and associated risk factors.

Methods: This study is based on data from an international, multicentric, prospective, longitudinal, community-based mother-infant cohort.

View Article and Find Full Text PDF

Background: Vaccination reduces mortality from infectious disease, which is the leading cause of death in children under 5 and bears a particularly high burden in low- and middle-income countries. The Global Vaccine Action Plan (2011-2020) has set a target of 90% vaccine coverage for all vaccines included in national immunization programs by 2020. The objectives of this study were to estimate vaccine coverage among children in Madagascar, Cambodia, and Senegal and to identify the risk factors associated with incomplete vaccination.

View Article and Find Full Text PDF

Environmental enteric dysfunction (EED) is an inflammatory syndrome postulated to contribute to stunted child growth and to be associated with intestinal dysbiosis and nutrient malabsorption. However, the small intestinal contributions to EED remain poorly understood. This study aimed to assess changes in the proximal and distal intestinal microbiota in the context of stunting and EED and to test for a causal role of these bacterial isolates in the underlying pathophysiology.

View Article and Find Full Text PDF

Introduction: Data regarding the acquisition of extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) in neonates at the community level are scarce in low-income and middle-income countries (LMICs), where the burden of neonatal sepsis is high.Our study aims at identifying and quantifying the role of the different routes of ESBL-PE transmission for neonates, which are still undefined in the community in LMICs.

Methods And Analysis: In a semirural community in Madagascar, 60 mothers and their neonates will be recruited at delivery, during which a maternal stool sample and meconium of the newborn will be collected.

View Article and Find Full Text PDF

Environmental enteric dysfunction (EED) is an elusive, inflammatory syndrome of the small intestine thought to be associated with enterocyte loss and gut leakiness and lead to stunted child growth. To date, the gold standard for diagnosis is small intestine biopsy followed by histology. Several putative biomarkers for EED have been proposed and are widely used in the field.

View Article and Find Full Text PDF

Background: Anaemia occurs in children when the haemoglobin level in the blood is less than the normal (11 g/dL), the consequence is the decrease of oxygen quantity in the tissues. It is a prevalent public health problem in many low-income countries, including Madagascar, and data on risk factors are lacking. We used existing data collected within the pathophysiology of environmental enteric dysfunction (EED) in Madagascar and the Central African Republic project (AFRIBIOTA project) conducted in underprivileged neighbourhoods of Antananarivo to investigate the factors associated with anaemia in children 24 to 59 months of age.

View Article and Find Full Text PDF

Background: In Southeast-Asia, where many conditions associated with dissemination of ESBL-producing Enterobacterales (ESBL-E) in the community are met, data from the community are scarce but show high ESBL-E carriage prevalence. Maternal ESBL-E colonization is considered a risk factor for neonatal colonization, which is the first step towards developing neonatal sepsis. Despite this, ESBL-E carriage prevalence and its risk factors during pregnancy or postpartum remain undefined in Southeast-Asia.

View Article and Find Full Text PDF

Environmental Enteric Dysfunction (EED) refers to an incompletely defined syndrome of inflammation, reduced absorptive capacity, and reduced barrier function in the small intestine. It is widespread among children and adults in low- and middle-income countries and is also associated with poor sanitation and certain gut infections possibly resulting in an abnormal gut microbiota, small intestinal bacterial overgrowth (SIBO) and stunting. We investigated bacterial pathogen exposure in stunted and non-stunted children in Antananarivo, Madagascar by collecting fecal samples from 464 children (96 severely stunted, 104 moderately stunted and 264 non-stunted) and the prevalence of SIBO in 109 duodenal aspirates from stunted children (61 from severely stunted and 48 from moderately stunted children).

View Article and Find Full Text PDF

Klebsiella pneumoniae can lead to a wide range of diseases including pneumonia, bloodstream and urinary tract infections. During a short period of a pulmonary plague epidemic in October 2017 in Madagascar, 12 K. pneumoniae isolates were identified in ten sputum and two buboes aspirate samples.

View Article and Find Full Text PDF

Background: Children in low- and middle-income countries are particularly vulnerable in the months following an initial health event (IHE), with increased risk of mortality caused mostly by infectious diseases. Due to exposure to a wide range of environmental stressors, hospitalization in itself might increase child vulnerability at discharge. The goal of this study was to disentangle the role of hospitalization on the risk of subsequent infection.

View Article and Find Full Text PDF

Diphtheria is a potentially devastating disease whose epidemiology remains poorly described in many settings, including Madagascar. Diphtheria vaccination is delivered in combination with pertussis and tetanus antigens and coverage of this vaccine is often used as a core measure of health system functioning. However, coverage is challenging to estimate due to the difficulty in translating numbers of doses delivered into numbers of children effectively immunised.

View Article and Find Full Text PDF

In 2019, the world faced a serious health challenge, the rapid spreading of a life-threatening viral pneumonia, coronavirus disease 2019 (COVID-19) caused by a betacoronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). As of January 2022 WHO statistics shows more than 5.6 million death and about 350 million infection by SARS-CoV-2.

View Article and Find Full Text PDF

Background: Timely and accurate identification of uropathogens and determination of their antimicrobial susceptibility is paramount to the management of urinary tract infections (UTIs). The main objective of this study was to develop an assay using LAMP (Loop mediated isothermal amplification) technology for simple, rapid and sensitive detection of the most common bacteria responsible for UTIs, as well as for the detection of the most prevalent genes (encoding cefotaximases from CTX-M group 1) responsible for resistance to 3rd generation of cephalosporins.

Method: We designed primers targeting Proteus mirabilis, while those targeting Escherichia coli, Klebsiella pneumoniae and Enterococcus faecalis and the CTX-M group 1 resistance gene were benchmarked from previous studies.

View Article and Find Full Text PDF

Background: Severe bacterial infections (SBIs) are a leading cause of neonatal deaths in low- and middle-income countries (LMICs). However, most data came from hospitals, which do not include neonates who did not seek care or were treated outside the hospital. Studies from the community are scarce, and few among those available were conducted with high-quality microbiological techniques.

View Article and Find Full Text PDF

Maternal group B Streptococcus (GBS) colonization is a major risk factor for neonatal GBS infection. However, data on GBS are scarce in low- and middle-income countries. Using sociodemographic data and vaginal swabs collected from an international cohort of mothers and newborns, this study aimed to estimate the prevalence of GBS colonization among pregnant women in Madagascar (n = 1,603) and Senegal (n = 616).

View Article and Find Full Text PDF

Background: This study aimed to compare the prevalence of intestinal parasite infestations (IPIs) in stunted children, compared to control children, in Ankasina and Andranomanalina Isotry (two disadvantaged neighborhoods of Antananarivo, Madagascar), to characterize associated risk factors and to compare IPI detection by real-time PCR and standard microscopy techniques.

Methodology/principal Findings: Fecal samples were collected from a total of 410 children (171 stunted and 239 control) aged 2-5 years. A single stool sample per subject was examined by simple merthiolate-iodine-formaldehyde (MIF), Kato-Katz smear and real-time PCR techniques.

View Article and Find Full Text PDF

Our gut microbiota is known as an efficient barrier for infection; however, the physiological processes involved are poorly understood. Stacy et al. recently shed light on the key contribution of taurine to the trainable resistance of the gut microbiota to infection.

View Article and Find Full Text PDF