Les ammoniums quaternaires (champs d'application, mode d'action, mécanismes de résistance, toxicité)

Les ammoniums quaternaires, principes actifs aux vertus antiseptiques, désinfectantes et conservatrices, entrent dans la composition de nombreuses spécialités à usage pharmaceutique, cosmétologique, industriel ou encore environnemental...Depuis quelques années, ces composés sont suspectés d'accroître la résistance des bactéries aux autres antimicrobiens, en particulier aux antibiotiques. Un mécanisme de résistance croisée a été mis en évidence: modifications membranaires et sur-expression de pompes d'efflux chez les micro-organismes ont été attribuées à l'usage abusif et inapproprié des ammoniums quaternaires, ces stratégies entraînant par la même occasion l'émergence de nouvelles résistances bactériennes aux antibiotiques. De plus, ces substances ne sont pas dénuées de toxicité pour l'homme et l'animal: le chlorure de benzalkonium a fait l'objet de plusieurs études; ces deux constats mettent en évidence l'existence actuelle d'un réel problème de santé publique vis-à-vis de ces composésQuaternary ammonium compounds, active principles to the virtues antiseptic, desinfectant and conservative, are used in many specialties for pharmaceutical, cosmetologic, industrial or even environmental use. In recent years, these compounds are suspected to increase the resistance of bacteria to other antimicrobials, especially antibiotics. Mechanism of cross resistance has been highlighted: membrane changes, overexpression of pumps of efflux in microorganisms have been assigned to use abusive and inappropriate of the quaternary ammonium compounds, these strategies leading at the same time to the emergence of new bacterial resistance to antibiotics. In addition, these substances are not devoid of toxicity for human and animal: the effect of benzalkonium chloride, representative of this class of compounds, has been the subject of several studies. These two findings highlight the current existence of a real problem of public health to these compoundsLYON1-BU Santé (693882101) / SudocRENNES1-BU Santé (352382103) / SudocSudocFranceF

Comparison of four DNA extraction kits efficiency for 16SrDNA microbiota profiling of diverse human samples

International audienceAim: The current study investigated the performance of 4 widely used DNA extraction kits using different types of high (stool) and low biomass samples (chyme, broncho alveolar lavage and sputum). Methods: Qiagen Powerfecal Pro DNA kit, Macherey Nucleospin Soil kit, Macherey Nucleospin Tissue Kit and MagnaPure LC DNA isolation kit III were evaluated in terms of DNA quantity, quality, diversity and composition profiles. Results: The quantity and quality of DNA varied among the four kits. The microbiota of the stool samples showed similar diversity and compositional profiles for the 4 kits. Conclusion: Despite differences in DNA quality and quantity, the 4 kits yielded similar results for stool samples, while all kits were not sensitive enough for low biomass samples

A French version of a questionnaire for measuring the intention to perform Standard IPC Precautions among health-care workers: A pilot study

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Risk factors for neurosurgical site infection after neurosurgery in Rennes, France: comparison of logistic and Cox models

International audienceThe logistic model is widely used to assess the risk factors for surgical site infections (SSIs). An alternative to the logistic model is the Cox model. The objective of this study was to compare these 2 models to identify the risk factors of SSIs in neurosurgery. The Cox model is a valid alternative for assessing the risk factors of SSIs

New insights into microbiota modulation-based nutritional interventions for neurodevelopmental outcomes in preterm infants

International audienceGut microbiota and the central nervous system have parallel developmental windows during pre and post-natal life. Increasing evidences suggest that intestinal dysbiosis in preterm infants predisposes the neonate to adverse neurological outcomes later in life. Understanding the link between gut microbiota colonization and brain development to tailor therapies aimed at optimizing initial colonization and microbiota development are promising strategies to warrant adequate brain development and enhance neurological outcomes in preterm infants. Breast-feeding has been associated with both adequate cognitive development and healthy microbiota in preterms. Infant formula are industrially produced substitutes for infant nutrition that do not completely recapitulate breastfeeding benefices and could be largely improved by the understanding of the role of breast milk components upon gut microbiota. In this review, we will first discuss the nutritional and bioactive component information on breast milk composition and its contribution to the assembly of the neonatal gut microbiota in preterms. We will then discuss the emerging pathways connecting the gut microbiota and brain development. Finally, we will discuss the promising microbiota modulation-based nutritional interventions (including probiotic and prebiotic supplementation of infant formula and maternal nutrition) for improving neurodevelopmental outcomes

Emergence of resistance to antibacterial agents: the role of quaternary ammonium compounds--a critical review.

International audienceQuaternary ammonium compounds (QACs) are widely distributed in hospitals, industry and cosmetics. Little attention has been focused on the potential impact of QACs on the emergence of antibiotic resistance in patients and the environment. To assess this issue, we conducted a literature review on QAC chemical structure, fields of application, mechanism of action, susceptibility testing, prevalence, and co- or cross-resistance to antibiotics. Special attention was paid to the effects of QACs on microflora; in particular, the issue of the potential of QACs for applying selective pressure on multiple-antibiotic-resistant organisms was raised. It was found that there is a lack of standardised procedures for interpreting susceptibility test results. QACs have different impacts on the minimum inhibitory concentrations of antibacterials depending on the antibacterial compound investigated, the resistance genes involved, the measuring methodology and the interpretative criteria. The unmet needs for adequate detection of reduced susceptibility to QACs and antibiotics include (i) a consensus definition for resistance, (ii) epidemiological cut-off values and (iii) clinical resistance breakpoints. This review advocates the design of international guidelines for QAC use

Bacterial gut dysbiosis is associated with Crohn’s disease symptoms but not with elevated fecal calprotectin

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Clostridium difficile O27 colitis: hospital-onset but community-acquired.

International audienceLarge outbreaks of Clostridium difficile (CD) associated colitis in North America and Europe have been attributed to the emergence of the epidemic/toxin PCR Ribotype O27 CD strain (CD027). Due to the increased virulence of this epidemic strain and its propension for causing outbreaks, we performed a structured risk-assessment approach in order to determine the risks associated with the introduction of this strain within our university hospital. From February 2009 to January 2010, we identified 31 cases of CD027 associated colitis, whereby twenty one (67.7%) had symptoms onset more than 48 hours after admission and were classified as nosocomial. These patients had received wide-spectrum antimicrobials for other infections in the hospital before CD027 colitis diagnosis. The 31 patients with CD027 were admitted in 20 different units, managed by distinct health-care workers (HCWs), and no contact was identified between patients during their hospital stay. Furthermore, infection control audits showed 100% compliance with institutional guidelines for control of CD colitis. These findings suggest that CD027 is most frequently acquired in the community and emerges sporadically under antibiotic pressure during hospitalization

Clostridium difficile infections: do we know the real dimensions of the problem?

International audienceClostridium difficile infection (CDI) is the primary cause of nosocomial diarrhoea in industrialised countries, usually occurring as a complication of antibiotic therapy in elderly patients. Landmark events contributed to boosting interest in CDI over the last 10 years, including the emergence of unusually severe and recurrent CDI due to the NAP1/BI/027 strain, as well as reports suggesting that CDI is also significantly encountered in patients previously considered at no risk, such as community-acquired CDI in patients with no recent antibiotic use, or CDI during pregnancy. Despite this growing interest from the medical community, we do not know the real dimensions of the disease for the following reasons: (i) despite comprehensive guidelines published in Europe and in the USA, most laboratories still use diagnostic tests with suboptimal sensitivity as a 'rule-out' test, hence a significant proportion of CDIs remain undiagnosed; (ii) use of PCR as a stand-alone test by others will probably overestimate the real incidence of CDI and jeopardise any comparison between institutions with different diagnostic procedures; and (iii) transversal studies, with optimum design and diagnostic tests, are rapidly outdated due to the dramatic changes in CDI epidemiology that may occur from one year to another. To get an accurate picture of the real dimensions of the CDI issue, we need more systematic use of an adequate and homogeneous diagnostic strategy in the field as well as the implementation of continuous monitoring of CDI incidence through surveillance programmes

Gut microbiota analysis for prediction of clinical relapse in Crohn’s disease

International audienceAbstract The role of intestinal bacterial microbiota has been described as key in the pathophysiology of Crohn’s disease (CD). CD is characterized by frequent relapses after periods of remission which are not entirely understood. In this paper, we investigate whether the heterogeneity in microbiota profiles in CD patients could be a suitable predictor for these relapses. This prospective observational study involved 259 CD patients, in which 41 provided an additional total of 62 consecutive fecal samples, with an average interval of 25 weeks in between each of these samples. Fecal microbiota was analyzed by massive genomic sequencing through 16 S rRNA amplicon sampling. We found that our 259 CD patients could be split into three distinct subgroups of microbiota (G1, G2, G3). From G1 to G3, we noticed a progressive decrease in alpha diversity (p ≤ 0.0001) but no change in the fecal calprotectin (FC) level. Focusing on the 103 consecutive samples from 41 CD patients, we showed that the patients microbiota profiles were remarkably stable over time and associated with increasing symptom severity. Investigating further this microbiota/severity association revealed that the first signs of aggravation are (1) a loss of the main anti-inflammatory Short-Chain Fatty Acids (SCFAs) Roseburia, Eubacterium , Subdoligranumum , Ruminococcus (P < 0.05), (2) an increase in pro-inflammatory pathogens Proteus , Finegoldia (P < 0.05) while (3) an increase of other minor SCFA producers such as Ezakiella , Anaerococcus , Megasphaera , Anaeroglobus , Fenollaria (P < 0.05). Further aggravation of clinical signs is significantly linked to the subsequent loss of these minor SCFAs species and to an increase in other proinflammatory Proteobacteria such as Klebsiella, Pseudomonas, Salmonella, Acinetobacter, Hafnia and proinflammatory Firmicutes such as Staphylococcus, Enterococcus, Streptococcus. (P < 0.05). To our knowledge, this is the first study (1) specifically identifying subgroups of microbiota profiles in CD patients, (2) relating these groups to the evolution of symptoms over time and (3) showing a two-step process in CD symptoms’ worsening. This paves the way towards a better understanding of patient-to-patient heterogeneity, as well as providing early warning signals of future aggravation of the symptoms and eventually adapting empirically treatments