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Abstract Phthalates constitute a family of anthropogenic chemicals developed to be used in the manufacture of plastics, solvents, and personal care products. Their dispersion and accumulation in many environments can occur at all stages of their use (from synthesis to recycling). However, many phthalates together with other accumulated engineered chemicals have been shown to interfere with hormone activities. These compounds are also in close contact with microorganisms that are free-living, in biofilms or in microbiota, within multicellular organisms. Herein, the activity of several phthalates and their substitutes were investigated on the opportunistic pathogen Legionella pneumophila, an aquatic microbe that can infect humans. Beside showing the toxicity of some phthalates, data suggested that Acetyl tributyl citrate (ATBC) and DBP (Di-n-butyl phthalate) at environmental doses (i.e. 10–6 M and 10–8 M) can modulate Legionella behavior in terms of motility, biofilm formation and response to antibiotics. A dose of 10–6 M mostly induced adverse effects for the bacteria, in contrast to a dose of 10–8 M. No perturbation of virulence towards Acanthamoeba castellanii was recorded. These behavioral alterations suggest that L. pneumophila is able to sense ATBC and DBP, in a cross-talk that either mimics the response to a native ligand, or dysregulates its physiology.

Abstract Background Almost 15% of patients with ulcerative colitis (UC) will require a proctocolectomy with ileal pouch–anal anastomosis (IPAA) as a result of fulminant colitis, dysplasia, cancer, or medical refractory diseases. Around 50% will experience pouchitis, an idiopathic inflammatory condition involving the ileal reservoir, responsible for digestive symptoms, deterioration in quality of life, and disability. Though the majority of initial cases of pouchitis are easily managed with a short course of antibiotics, in about 10% of cases, inflammation of the pouch becomes chronic with very few treatments available. Previous studies have suggested that manipulating the composition of intestinal flora through antibiotics, probiotics, and prebiotics achieved significant results for treating acute episodes of UC-associated pouchitis. However, there is currently no established effective treatment for chronic antibiotic-dependent pouchitis. Fecal microbiota transplantation (FMT) is a novel therapy involving the transfer of normal intestinal flora from a healthy donor to a patient with a medical condition potentially caused by the disrupted homeostasis of intestinal microbiota or dysbiosis. Methods Our project aims to compare the delay of relapse of chronic recurrent pouchitis after FMT versus sham transplantation. Forty-two patients with active recurrent pouchitis after having undergone an IPAA for UC will be enrolled at 12 French centers. The patients who respond to antibiotherapy will be randomized at a ratio of 1:1 to receive either FMT or sham transplantation. Discussion On April 30, 2014, the World Health Organization published an alarming report on antibiotic resistance. Finding an alternative medical treatment to antibiotics in order to prevent relapses of pouchitis is therefore becoming increasingly important given the risk posed by multiresistant bacteria. Moreover, if the results of this study are conclusive, FMT, which is less expensive than biologics, could become a routine treatment in the future. Trial registration ClinicalTrials.gov, NCT03524352 . Registered on 14 May 2018.

Phthalates are used in a variety of applications—for example, as plasticizers in polyvinylchloride products to improve their flexibility—and can be easily released into the environment. In addition to being major persistent organic environmental pollutants, some phthalates are responsible for the carcinogenicity, teratogenicity, and endocrine disruption that are notably affecting steroidogenesis in mammals. Numerous studies have thus focused on deciphering their effects on mammals and eukaryotic cells. While multicellular organisms such as humans are known to display various microbiota, including all of the microorganisms that may be commensal, symbiotic, or pathogenic, few studies have aimed at investigating the relationships between phthalates and bacteria, notably regarding their effects on opportunistic pathogens and the severity of the associated pathologies. Herein, the effects of phthalates and their substitutes were investigated on the human pathogen, Pseudomonas aeruginosa, in terms of physiology, virulence, susceptibility to antibiotics, and ability to form biofilms. We show in particular that most of these compounds increased biofilm formation, while some of them enhanced the bacterial membrane fluidity and altered the bacterial morphology.

Azithromycin (AZM) is a 15-membered-ring macrolide that presents a broad-spectrum antimicrobial activity against Gram-positive bacteria and atypical microorganisms but suffers from a poor diffusion across the outer-membrane of Gram-negative bacilli, including Pseudomonas aeruginosa (PA). However, AZM has demonstrated clinical benefits in patients suffering from chronic PA respiratory infections, especially cystic fibrosis patients. Since the rise of multidrug-resistant PA has led to a growing need for new therapeutic options, this macrolide has been proposed as an adjunctive therapy. Clinical trials assessing AZM in PA acute pneumonia are scarce. However, a careful examination of the available literature provides good rationales for its use in that context. In fact, 14- and 15-membered-ring macrolides have demonstrated immunomodulatory and immunosuppressive effects that could be of major interest in the management of acute illness. Furthermore, growing evidence supports a downregulation of PA virulence dependent on direct interaction with the ribosomes, and based on the modulation of several key regulators from the Quorum Sensing network. First highlighted in vitro, these interesting properties of AZM have subsequently been confirmed in the animal models. In this review, we systematically analyzed the literature regarding AZM immunomodulatory and anti-PA effects. In vitro and in vivo studies, as well as clinical trials were reviewed, looking for rationales for AZM use in PA acute pneumonia.

ABSTRACT Diabetes is marked by a range of complications, including chronic infections that can lead to limb amputation. The treatment of infected wounds is disrupted by arteriopathies that reduce tissue perfusion as well as by the critical development of bacterial resistance. We evaluated the impact of a local application of bacteriophages compared to that of a per os administration of amoxicillin-clavulanic acid in a mouse model of Staphylococcus aureus wound infection. We found that phage treatment resulted in improved clinical healing and a reduction in local bacterial load at 7 and 14 days postinfection. Unlike antibiotics, phage therapy did not deplete the intestinal microbiota of treated animals. Amoxicillin resulted in a reduction of alpha and beta diversities of the murine microbiota and disturbed architecture even 7 days after the end of treatment, whereas phage treatment did not impinge on the microbiota. IMPORTANCE The management of diabetic foot infections is frequently a dead end for surgeons and infectious disease specialists. When the pathogen to be treated is not resistant to conventional antibiotics, the latter tend to unbalance the intestinal microbiota, which is linked to multiple pathologies. A local treatment with bacteriophages, in addition to being as much or even more effective than antibiotics from a clinical and microbiological point of view, makes it possible to respect the patient’s microbiota. These results suggest that the use of this therapeutic alternative is a major avenue and that the introduction of recommendations for their use is now necessary.

Context: The incidence of early-onset neonatal infection has greatly decreased, but a new diagnostic approach is needed to avoid overdiagnosis and overtreatment. The aim of this study was to assess the potential impact of an algorithm incorporating umbilical-cord-blood procalcitonin (PCT) level on neonatal antibiotics prescription rate as compared with current practice.Material and methods: We conducted a prospective study in three maternity wards in France. All term and preterm neonates with the usual risk factors for neonatal group B Streptococcus infection were eligible for umbilical-cord-blood PCT testing. We compared the proportion of neonates who were exposed early to antibiotics (before 6 days of life) to that of neonates for whom antibiotics prescription would be indicated according to the PCT-based algorithm.Results: Among the 3,080 neonates included, 1 neonate presented with certain infection and 38 neonates with probable infection. The global antibiotics prescription rate was 4.6% [95% confidence interval (CI), 4.1–5]. With the PCT-based algorithm, the potential decrease in prescription rate would be 1.8% (95% CI, 1.3–2.3), corresponding to a 39% (95% CI, 37.3–40.7) relative reduction in antibiotics exposure (p < 0.05).Conclusion: These results suggest that the umbilical-cord-blood PCT-based algorithm could significantly help the clinicians in their antibiotic prescription decision to decrease neonatal antibiotics exposure as compared with current practice. If validated in a larger interventional randomized study, this approach could help clinicians stratify the risk of early-onset neonatal infection and initiate early antibiotics treatment in newborns at high risk of infection while limiting the deleterious effects of useless prescriptions in non-infected newborns.

Pseudomonas aeruginosa (PA) expresses the type III secretion system (T3SS) and effector exoenzymes that interfere with intracellular pathways. Natural killer (NK) cells play a key role in antibacterial immunity and their activation is highly dependent on IL-12 produced by myeloid cells. We studied PA and NK cell interactions and the role of IL-12 using human peripheral blood mononuclear cells, sorted human NK cells, and a human NK cell line (NK92). We used a wild-type (WT) strain of PA (PAO1) or isogenic PA-deleted strains to delineate the role of T3SS and exoenzymes. Our hypotheses were tested in vivo in a PA-pneumonia mouse model. Human NK cells or NK92 cell line produced low levels of IFN-γ in response to PA without IL-12 stimulation, whereas PA significantly increased IFN-γ after IL-12 priming. The modulation of IFN-γ production by PA required bacteria-to-cell contact. Among T3SS effectors, exoenzyme T (ExoT) upregulates IFN-γ production and control ERK activation. In vivo, ExoT also increases IFN-γ levels and the percentage of IFN-γ+ NK cells in lungs during PA pneumonia, confirming in vitro data. In conclusion, our results suggest that T3SS could modulate the production of IFN-γ by NK cells after PA infection through ERK activation.

Chronic Periodontitis (CP) is an inflammatory disease of bacterial origin that results in alveolar bone destruction. Porphyromonas gingivalis (Pg), one of the main periopathogens, initiates an inflammatory cascade by host immune cells thereby increasing recruitment and activity of osteoclasts, the bone resorbing cells, through enhanced production of the crucial osteoclastogenic factor, RANK-L. Antibodies directed against some cytokines (IL-1β, IL-6 and TNF-α) failed to exhibit convincing therapeutic effect in CP. It has been suggested that IL-33, could be of interest in CP.the present study aims to analyze whether and how IL-33 and RANK-L and/or their interplay are involved in the bone destruction associated to CP.mRNAs and protein expressions of IL-33 and RANK-L were analyzed in healthy and CP human gingival samples by immunohistochemistry (IHC) and RT-qPCR. Murine experimental periodontitis (EP) was induced using Pg infected ligature and Pg free ligature around the first maxillary molar. Alveolar bone loss was recorded by μCT. Mouse gingival explants were stimulated for 24 hours with IL-33 and RANK-L mRNA expression investigated by RT-qPCR. Human oral epithelial cells were infected by Pg for 6, 12; 24 hours and IL-33 and RANK-L mRNA expressions were analyzed by RT-qPCR.IL-33 is overexpressed in gingival epithelial cells in human affected by CP as in the murine EP. In human as in murine gingival cells, RANK-L was independently induced by Pg and IL-33. We also showed that the Pg-dependent RANK-L expression in gingival epithelial cells occured earlier than that of IL-33.Our results evidence that IL-33 overexpression in gingival epithelial cells is associated with CP and may trigger RANK-L expression in addition to a direct effect of Pg. Finally, IL-33 may act as an extracellular alarmin (danger signal) showing proinflammatory properties in CP perpetuating bone resorption induced by Pg infection.

The diffusion of antibiotics in endocarditis vegetation bacterial masses has not been described, although it may influence the efficacy of antibiotic therapy in endocarditis. The objective of this work was to assess the diffusion of ofloxacin in experimental endocarditis vegetation bacterial masses using synchrotron-radiation UV fluorescence microspectroscopy. Streptococcal endocarditis was induced in 5 rabbits. Three animals received an unique i.v. injection of 150 mg/kg ofloxacin, and 2 control rabbits were left untreated. Two fluorescence microscopes were coupled to a synchrotron beam for excitation at 275 nm. A spectral microscope collected fluorescence spectra between 285 and 550 nm. A second, full field microscope was used with bandpass filters at 510-560 nm. Spectra of ofloxacin-treated vegetations presented higher fluorescence between 390 and 540 nm than control. Full field imaging showed that ofloxacin increased fluorescence between 510 and 560 nm. Ofloxacin diffused into vegetation bacterial masses, although it accumulated in their immediate neighborhood. Fluorescence images additionally suggested an ofloxacin concentration gradient between the vegetation peripheral and central areas. In conclusion, ofloxacin diffuses into vegetation bacterial masses, but it accumulates in their immediate neighborhood. Synchrotron radiation UV fluorescence microscopy is a new tool for assessment of antibiotic diffusion in the endocarditis vegetation bacterial masses.

Infections are the most frequent cause of complications in trauma patients. Post-traumatic immune suppression (IS) exposes patients to pneumonia (PN). The main pathogen involved in PN is Methicillin Susceptible Staphylococcus aureus (MSSA). Dendritic cells () may be centrally involved in the IS. We assessed the consequences of hemorrhage on pneumonia outcomes and investigated its consequences on DCs functions. A murine model of hemorrhagic shock with a subsequent MSSA pneumonia was used. Hemorrhage decreased the survival rate of infected mice, increased systemic dissemination of sepsis and worsened inflammatory lung lesions. The mRNA expression of Tumor Necrosis Factor-alpha (TNF-α), Interferon-beta (IFN-β) and Interleukin (IL)-12p40 were mitigated for hemorrhaged-mice. The effects of hemorrhage on subsequent PN were apparent on the pDCs phenotype (reduced MHC class II, CD80, and CD86 molecule membrane expression). In addition, hemorrhage dramatically decreased CD8(+) cDCs- and CD8(-) cDCs-induced allogeneic T-cell proliferation during PN compared with mice that did not undergo hemorrhage. In conclusion, hemorrhage increased morbidity and mortality associated with PN; induced severe phenotypic disturbances of the pDCs subset and functional alterations of the cDCs subset. After hemorrhage, a preventive treatment with CpG-ODN or Monophosphoryl Lipid A increased transcriptional activity in DCs (TNF-α, IFN-β and IL-12p40) and decreased mortality of post-hemorrhage MSSA pneumonia.

Objectives: To measure the in vitro post-antibiotic effect (PAE) and post--lactamase inhibitor effect (PLIE) of a ceftazidimesulbactam combination on bacteria producing extended-spectrum -lactamases (ESBLs).Methods: PAE and PLIE were studied for ESBL-producing strains of Escherichia coli and Klebsiella pneumoniae. Two ATCC -lactamase-negative strains of E. coli and K. pneumoniae were used as controls. The MICs of a ceftazidimesulbactam combination were determined with a fixed concentration of sulbactam (8 mg/L). The organisms were exposed to the antibiotics at twice the MIC for 2 h before removal of the antibiotics by filtration of the culture. Bacteria on the filter were resuspended in drug-free medium to determine the PAE and in medium containing ceftazidime, at the same concentration as originally present, to determine the PLIE.Results: The PAE of ceftazidime was similar for bacteria producing the same ESBL except for E. coli producing CTX-M-1. PLIE values varied according to the type of -lactamase but similar results were observed for the strains producing the same ESBLs. PLIEs were longer than PAEs and were longer when the MICs of ceftazidime were lower.Conclusions: To the best of our knowledge, we describe here for the first time an in vitro PLIE for a ceftazidimesulbactam combination on different bacteria producing different ESBLs. These findings indicate that suicide inhibitors may be used in combination with third-generation cephalosporins. [ABSTRACT FROM AUTHOR]