Parabacteroides distasonis Properties Linked to the Selection of New Biotherapeutics.

Dysbiotic microbiota is often associated with health issues including inflammatory bowel disease or ulcerative colitis. In order to counterbalance host disorder caused by an alteration in the gut composition, numerous studies have focused on identifying new biotherapeutic products (NBPs). Among the promising NBPs is Parabacteroides distasonis, a gut microbiota member part of the core microbiome that recently has received much attention due to the numerous beneficial properties it brings to its host. In this study, the properties linked to the selection of NBPs were screened in 14 unrelated P. distasonis strains, including resistance to gastric conditions, adherence (Caco-2 model), transepithelial resistance (Caco-2 model), and immunomodulation, on nontreated and LPS-stimulated cells (HT-29 and peripheral blood mononuclear cells (PBMCs)). This approach allowed for the identification of five strains that combined almost all the in vitro biotherapeutic properties tested. However, all the P. distasonis strains induced the overproduction of proinflammatory cytokines on PBMCs, which was counteracted by the overproduction of the anti-inflammatory cytokines. Among these five strains, two particularly retained our attention as a potential NBP, by showing strong health-promoting function, the lowest overproduction of proinflammatory cytokines on PBMCs, and no detrimental effect on the host.

In Silico Study of Cell Surface Structures of Parabacteroides distasonis Involved in Its Maintenance within the Gut Microbiota.

The health-promoting Parabacteroides distasonis, which is part of the core microbiome, has recently received a lot of attention, showing beneficial properties for its host and potential as a new biotherapeutic product. However, no study has yet investigated the cell surface molecules and structures of P. distasonis that allow its maintenance within the gut microbiota. Moreover, although P. distasonis is strongly recognized as an intestinal commensal species with benefits for its host, several works displayed controversial results, showing it as an opportunistic pathogen. In this study, we reported gene clusters potentially involved in the synthesis of capsule, fimbriae-like and pili-like cell surface structures in 26 P. distasonis genomes and applied the new RfbA-typing classification in order to better understand and characterize the beneficial/pathogenic behavior related to P. distasonis strains. Two different types of fimbriae, three different types of pilus and up to fourteen capsular polysaccharide loci were identified over the 26 genomes studied. Moreover, the addition of data to the rfbA-type classification modified the outcome by rearranging rfbA genes and adding a fifth group to the classification. In conclusion, the strain variability in terms of external proteinaceous structure could explain the inter-strain differences previously observed of P. distasonis adhesion capacities and its potential pathogenicity, but no specific structure related to P. distasonis beneficial or detrimental activity was identified.

Surface Properties of Parabacteroides distasonis and Impacts of Stress-Induced Molecules on Its Surface Adhesion and Biofilm Formation Capacities.

The gut microbiota is a complex and dynamic ecosystem whose balance and homeostasis are essential to the host's well-being and whose composition can be critically affected by various factors, including host stress. Parabacteroides distasonis causes well-known beneficial roles for its host, but is negatively impacted by stress. However, the mechanisms explaining its maintenance in the gut have not yet been explored, in particular its capacities to adhere onto (bio)surfaces, form biofilms and the way its physicochemical surface properties are affected by stressing conditions. In this paper, we reported adhesion and biofilm formation capacities of 14 unrelated strains of P. distasonis using a steam-based washing procedure, and the electrokinetic features of its surface. Results evidenced an important inter-strain variability for all experiments including the response to stress hormones. In fact, stress-induced molecules significantly impact P. distasonis adhesion and biofilm formation capacities in 35% and 23% of assays, respectively. This study not only provides basic data on the adhesion and biofilm formation capacities of P. distasonis to abiotic substrates but also paves the way for further research on how stress-molecules could be implicated in P. distasonis maintenance within the gut microbiota, which is a prerequisite for designing efficient solutions to optimize its survival within gut environment.

Impact of a Model Used to Simulate Chronic Socio-Environmental Stressors Encountered during Spaceflight on Murine Intestinal Microbiota.

During deep-space travels, crewmembers face various physical and psychosocial stressors that could alter gut microbiota composition. Since it is well known that intestinal dysbiosis is involved in the onset or exacerbation of several disorders, the aim of this study was to evaluate changes in intestinal microbiota in a murine model used to mimic chronic psychosocial stressors encountered during a long-term space mission. We demonstrate that 3 weeks of exposure to this model (called CUMS for Chronic Unpredictable Mild Stress) induce significant change in intracaecal ß-diversity characterized by an important increase of the Firmicutes/Bacteroidetes ratio. These alterations are associated with a decrease of Porphyromonadaceae, particularly of the genus Barnesiella, a major member of gut microbiota in mice and humans where it is described as having protective properties. These results raise the question of the impact of stress-induced decrease of beneficial taxa, support recent data deduced from in-flight experimentations and other ground-based models, and emphasize the critical need for further studies exploring the impact of spaceflight on intestinal microbiota in order to propose strategies to countermeasure spaceflight-associated dysbiosis and its consequences on health.

Protozoans in subgingival biofilm: clinical and bacterial associated factors and impact of scaling and root planing treatment.

Objective: In patients with periodontitis, identification of protozoans and evaluation of some bacteria and clinical parameters associated and assessment of scaling and root planing (SRP) impact on their detection. Methods: Before and after SRP, subgingival microbiota was collected in two pathological and one healthy site from 30 periodontitis patients. One healthy site from 30 control patients was also sampled. The usual clinical periodontal parameters were recorded; microbial detection was determined by PCR hybridization system for bacteria and qPCR for protozoans. Results: In periodontitis group, Trichomonas tenax and two subtypes of Entamoeba gingivalis (ST1 and a variant ST2) were detected in respectively 33.3%, 70% and 18.3% of pathological samples, and in 6.7%, 10% and 3.3% healthy samples. In control group, ST1 alone was found in 3.3% of individuals. ST1 was associated with Gingival Index, Clinical Attachment Level (p ≤ 0.03) and with the total bacterial count (p = 0.02). T. tenax alone was associated with P. gingivalis, T. denticola and E. nodatum (p ≤ 0,02). After therapy, only T. tenax detection decreased significantly (p = 0.004) and no association between the protozoan elimination and improvement of pathological sites was found. Conclusions: Protozoans were associated with some clinical parameters and/or periodontopathogens in patients with periodontitis.

Hypergravity disrupts murine intestinal microbiota.

During spaceflight, organisms are subjected to various physical stressors including modification of gravity (G) that, associated with lifestyle, could lead to impaired immunity, intestinal dysbiosis and thus potentially predispose astronauts to illness. Whether space travel affects microbiota homeostasis has not been thoroughly investigated. The aim of this study was to evaluate changes in intestinal microbiota and mucosa in a ground-based murine model consisting in a 21-days confinement of mice in a centrifuge running at 2 or 3G. Results revealed an increased α-diversity and a significant change in intracaecal ß-diversity observed only at 3G, with profiles characterized by a decrease of the Firmicutes/Bacteroidetes ratio. Compared to 1G microbiota, 12.1% of the taxa were significantly impacted in 3G microbiota, most of them (78%) being enriched. This study shows a G-level-dependent disruption of intracaecal microbiota, without alteration of mucosal integrity. These first data reinforce those recently obtained with in-flight experimentations or microgravity models, and emphasize the critical need for further studies exploring the impact of spaceflight on intestinal microbiota in order to optimize long-term space travel conditions.

Bone marrow vs Wharton's jelly mesenchymal stem cells in experimental sepsis: a comparative study.

BACKGROUND: The use of mesenchymal stem cells (MSCs) is being extensively studied in clinical trials in the setting of various diseases including diabetes, stroke, and progressive multiple sclerosis. The unique immunomodulatory properties of MSCs also point them as a possible therapeutic tool during sepsis and septic shock, a devastating syndrome associated with 30-35% mortality. However, MSCs are not equal regarding their activity, depending on their tissue origin. Here, we aimed at comparing the in vivo properties of MSCs according to their tissue source (bone marrow (BM) versus Wharton's jelly (WJ)) in a murine cecal ligation and puncture (CLP) model of sepsis that mimics a human peritonitis. We hypothesized that MSC properties may vary depending on their tissue source in the setting of sepsis. METHODS: CLP, adult, male, C57BL/6 mice were randomized in 3 groups receiving respectively 0.25 × 106 BM-MSCs, 0.25 × 106 WJ-MSCs, or 150 µL phosphate-buffered saline (PBS) intravenously 24 h after the CLP procedure. RESULTS: We observed that both types of MSCs regulated leukocyte trafficking and reduced organ dysfunction, while only WJ-MSCs were able to improve bacterial clearance and survival. CONCLUSION: This study highlights the importance to determine the most appropriate source of MSCs for a given therapeutic indication and suggests a better profile for WJ-MSCs during sepsis.

Clinical-grade mesenchymal stem cells derived from umbilical cord improve septic shock in pigs.

BACKGROUND: Septic shock is the leading cause of death in intensive care units. The pathophysiological complexity of this syndrome contributes to an absence of specific treatment. Several preclinical studies in murine models of septic shock have shown improvements to organ injury and survival after administration of mesenchymal stem cells (MSCs). To better mimic a clinical approach in humans, we investigated the impact of randomized controlled double-blind administration of clinical-grade umbilical cord-derived MSCs to a relevant pig model of septic shock. METHODS: Septic shock was induced by fecal peritonitis in 12 male domestic pigs. Animals were resuscitated by an experienced intensivist including fluid administration and vasopressors. Four hours after the induction of peritonitis, pigs were randomized to receive intravenous injection of thawed umbilical cord-derived MSCs (UCMSC) (1 × 106 UCMSCs/kg diluted in 75 mL hydroxyethyl starch (HES), (n = 6) or placebo (HES alone, n = 6). Researchers were double-blinded to the treatment administered. Hemodynamic parameters were continuously recorded. Gas exchange, acid-base status, organ function, and plasma cytokine concentrations were assessed at regular intervals until 24 h after the onset of peritonitis when animals were sacrificed under anesthesia. RESULTS: Peritonitis induced profound hypotension, hyperlactatemia, and multiple organ failure. These disorders were significantly attenuated when animals were treated with UCMSCs. In particular, cardiovascular failure was attenuated, as attested by a better mean arterial pressure and reduced lactatemia, despite lower norepinephrine requirements. As such, UCMSCs improved survival in this very severe model (60% survival vs. 0% at 24 h). CONCLUSION: UCMSCs administration is beneficial in this pig model of polymicrobial septic shock.

Assessment of transpulmonary absorption of ethanol from alcohol-based hand rub.

BACKGROUND: Alcohol-based hand rubs (ABHRs) have been associated with a reduction of nosocomial infections. Despite the worldwide introduction of these products in health care settings, the aim of this study was to assess the transpulmonary absorption of ethanol contains in ABHRs used by health care workers (HCWs) in real conditions of work shift. METHODS: Twenty-six HCWs of Nancy University Hospital were included. Research consisted in monitoring participants during 4 hours of work shift to assess their exposure to ethanol. The measurement of ethanol vapors in exhaled breath was performed using a class B ethylometer (Alco-Sensor FST). Ethanol concentration in inhaled breath was measured using Gilian pump LFS-113. Concentration of ethanol, acetaldehyde, and acetate in blood and urine samples were determined using gas chromatography with flame ionization detector. RESULTS: Participants were 12% male and 88% female. The mean age was 40 ± 8 years. None of the employees included in the study presented any traces of ethanol or its metabolites in the blood or urine. Ethanol (0.08 ± 0.07 mg/L) was detected in the breath of 10 HCWs at 1 to 2 minutes postexposure. The mean concentration of ethanol in the inhaled air was 46.2 mg/m. CONCLUSION: Absorption of ethanol vapor from ABHRs among HCWs during their care activities was not detected. Quantification of ethanol fumes inhaled during 4 hours of work shift was below the regulatory limitations of exposure to ethanol.

Assessment of exposure to ethanol vapors released during use of Alcohol-Based Hand Rubs by healthcare workers.

BACKGROUND: Despite the increasing use of Alcohol-Based Hand Rub solutions, few studies have quantified the concentrations of inhaled ethanol. OBJECTIVE: The aim of this study was to assess ethanol exposure during hygienic and surgical hand disinfection practices. METHOD: Ethanol concentrations were measured at the nose level of a wooden dummy and human volunteers. Two systems were used in parallel to determine short-term ethanol vapor exposures: activated charcoal tubes followed by gas chromatography analysis and direct reading on a photoionization detector (PID). Exposure was assessed for 4 different sequences (N=10) reproducing hand rubs for simple surgery, nursing care, intensive care and surgical scrub. RESULTS: The ethanol concentrations measured were of a similar order between the dummy and volunteers. The concentrations obtained by PID were higher than the gas chromatography values for the simple care (45%) and nursing care (27%) sequences and reflected specific exposure peaks of ethanol, whereas ethanol concentrations were continuously high for intensive care (440 mg m(-3)) or surgical scrub (650 mg m(-3)). CONCLUSION: Ethanol concentrations were similar for these two exposure assessment methods and demonstrated a relationship between handled doses and inhaled doses. However, the ethanol vapors released during hand disinfection were safe for the healthcare workers.

Emergence of hand contamination with Aspergillus during demolition work.

Hand rubbing with hydro-alcoholic solutions prevent the exogenous nosocomial infection, but the hydro-alcoholic solutions were not sporicidal. A major program of demolition was organized on the area of the University Hospital of Nancy (France) between 2007 and 2010, and this period is often considered as a possible source of suspending Aspergillus spores. This study shows the emergence of Aspergillus on the hands of the medical students during demolition period despite the same quality of hand hygiene.

Prospective observational study to assess hand skin condition after application of alcohol-based hand rub solutions.

BACKGROUND: The use of alcohol-based hand rub solutions (ABHRSs) in health care settings has been associated with increased hand hygiene compliance and reduced rates of nosocomial infection. Deterioration in hand skin condition leads to impaired barrier function, changes in skin flora, and increased bacterial shedding. Thus, poor skin condition can increase the risk of infection. This study evaluated the hand skin condition and dermal tolerance among health care workers (HCWs) after ABHRS application. METHODS: The study group comprised 231 HCWs (34% nurses, 22% nurse assistants, and 15% hospital cleaners). The mean participant age was 40 years. Stratum corneum hydration and superficial sebum content and surface pH of the skin were measured on the back and palm of each participant's dominant hand before and after ABHRS use. A self-assessment questionnaire was administered to collect information about the participants, their skin problems, and their perception of the ABHRS. RESULTS: The study group was 83% females. Skin hydration at the 2 assessment sites was markedly increased after ABHRS use (P < .0001). The mean pH value did not change significantly on the back of the hand, but did change significantly on the palm (P = .012). The superficial sebum content decreased significantly on the palm (P < .0001), but not on the back of the hand. HCWs reported excellent or good skin tolerance of ABHRS in 73% of cases. CONCLUSION: ABHRSs are well tolerated and do not dry the skin. pH and superficial sebum values decreased slightly, but these decreases did not affect skin barrier function. Values remained within the physiological range.

Factors determining poor practice in alcoholic gel hand rub technique in hospital workers.

BACKGROUND: Hand hygiene of healthcare personnel is one of the most important interventions for reducing transmission of nosocomial pathogens. Previous studies have demonstrated that the use of alcohol-based hand gel increases hand hygiene compliance, but that effective use of this product cannot be taken for granted. OBJECTIVE: Evaluate factors associated with poor hand hygiene effectiveness of hospital workers using an alcohol-based hand gel and the effect of an education program. DESIGN: A direct observational prospective study of hand hygiene effectiveness prior to training and immediately after training. SETTING AND SUBJECTS: 3067 hospital workers of different professional categories in several hospital units in the University Hospital of Nancy (France). RESULTS: Time after program start (OR 0.97, 95%CI 0.96-0.97) and being female (OR 0.37, 0.24-0.58) were highly associated with increased effectiveness of hand hygiene prior to training. Wearing rings other than a wedding ring (OR 1.8, 1.2-2.7), a bracelet (OR 2.0, 1.1-3.6), a watch (OR 1.9, 1.3-2.9) and having long nails were associated with ineffective hand rub use. Professional background was also a strong predictor with nurses and especially senior nurses demonstrating much better effectiveness than all other professional groups. Wearing wedding rings or long sleeves, and having varnished nails, visibly dirty hands prior to washing and cutaneous lesions were not associated with effective gel use. CONCLUSION: These results demonstrate that an educational program can significantly improve the proper practices for using hand rub and hand washing compliance. This study has also demonstrated that wearing rings, bracelets, watches and long nails impair hand gel application but that wedding rings, long sleeves and varnished nails do not. The finding of that hand hygiene effectiveness increased with time even prior to training indicates that knowledge gained by staff trained early diffused into those who had not yet been trained.

Comparative in situ study of the intestinal absorption of aluminum, manganese, nickel, and lead in rats.

This comparative study of the intestinal absorption of four toxic metals (aluminum, manganese, nickel, and lead) carried out in rats using the in situ intestinal perfusion technique was able to measure the partition of each metal between the intestine (intestinal retention), the blood circulation, and target tissues after 1 h. The perfused metal solutions were at concentrations likely to occur during oral intoxication. It was found that aluminum (48 and 64 mM), even as a citrate complex, crossed the brush border with difficulty (0.4% of the perfused amount); about 60% of this was retained in the intestine and the remainder was found in target tissues (about 36%). Conversely, lead (4.8-48 microM) penetrated the intestine more easily (about 35% of the perfused amount), was slightly retained (about 12% of the input), and was soon found in the tissues (about 58% of the input) and to a lesser degree in circulation (about 29%). Within the same concentration range, nickel and manganese showed certain similarities, such as a reduced crossing of the brush border proportional to the increase in the concentration perfused (0.17-9.5 mM). There was similar intestinal retention and absorption (about 80% and 20% of the input, respectively). Manganese crossed the brush border more easily and was diffused more rapidly into tissues. Finally, the addition of equimolar amounts of iron (4.7 mM) produced opposite effects on the absorption of the two elements, inhibiting manganese and showing a trend to increase in nickel absorption. This could be the result of competition between Fe2+ and Mn2+ for the same transcellular transporters and the slight predominance of paracellular mechanism in the event of "Fe2+-Ni2+" association.