Draft Genome Sequences of Two Pseudomonas aeruginosa Multidrug-Resistant Clinical Isolates, PAL0.1 and PAL1.1

International audiencePseudomonas aeruginosa infections are challenging due to intrinsic and acquired resistance mechanisms. We report here the draft genome sequences of two multidrug-resistant strains—PAL0.1, isolated from the airways of an intensive care unit (ICU) patient with ventilator-associated pneumonia, and PAL1.1, isolated from blood cultures of an ICU patient with sepsis

Draft Genome Sequences of Two Carbapenemase-Producing Klebsiella pneumoniae Strains Isolated from Blood Cultures

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PscI is a type III secretion needle anchoring protein with in vitro polymerization capacities.

International audienceThe export of bacterial toxins across the bacterial envelope requires the assembly of complex, membrane-embedded protein architectures. Pseudomonas aeruginosa employs type III secretion (T3S) injectisome to translocate exotoxins directly into the cytoplasm of a target eukaryotic cell. This multi-protein channel crosses two bacterial membranes and extends further as a needle through which the proteins travel. We show in this work that PscI, proposed to form the T3S system (T3SS) inner rod, possesses intrinsic properties to polymerize into flexible and regularly twisted fibrils and activates IL-1β production in mouse bone marrow macrophages in vitro. We also found that point mutations within C-terminal amphipathic helix of PscI alter needle assembly in vitro and T3SS function in cell infection assays, suggesting that this region is essential for an efficient needle assembly. The overexpression of PscF partially compensates for the absence of the inner rod in PscI-deficient mutant by forming a secretion-proficient injectisome. All together, we propose that the polymerized PscI in P. aeruginosa optimizes the injectisome function by anchoring the needle within the envelope-embedded complex of the T3S secretome and - contrary to its counterpart in Salmonella - is not involved in substrate switching

Impact of the Timing of Antibiotic Administration on Digestive Colonization with Carbapenemase-Producing Enterobacteriaceae in a Murine Model

International audienceWhile antibiotic use is a risk factor of carbapenemase-producing Enterobacteriaceae (CPE) acquisition, the importance of timing of antibiotic administration relative to CPE exposure remains unclear. In a murine model of gut colonization by New Delhi metallo-beta-lactamase-1 (NDM-1)-producing Klebsiella pneumoniae, a single injection of clindamycin within at most 1 week before or after CPE exposure induced colonization persisting up to 100 days. The timing of antibiotic administration relative to CPE exposure may be relevant to infection control and antimicrobial stewardship approaches

Classification and Regression Trees for Bacterial Vaginosis Diagnosis in Pregnant Women Based on High-Throughput Quantitative PCR

International audienceBacterial vaginosis (BV) diagnosis in pregnancy is based on the Nugent score, which consists of semiquantitation of bacterial morphotypes. Limited data exist concerning molecular-based diagnosis in asymptomatic pregnant women. Using high-throughput quantitative PCR, 34 microorganisms were screened in asymptomatic pregnant women and compared with the Nugent score. Three-hundred and four vaginal samples had a Nugent score <7 (69.9%) and 131, a Nugent score ≥7 (30.1%), consistent with BV. More pregnant women with BV share Atopobium vaginae, bacterial vaginosis associated bacteria-2, Gardnerella spp., Mobiluncus curtisii, Mo. mulieris, Mycoplasma hominis, Ureaplasma urealyticum, Prevotella bivia, Megasphaera 1, and Megasphaera 2 in their vaginal sample. Fewer pregnant women with BV share Lactobacillus crispatus, L. gasseri, L. jensenii, and Enterococcus faecalis in their vaginal sample (P < 0.001). Classification and regression tree analysis was performed to determine which combinations of detected bacteria optimally diagnose BV in this population. A set of only four bacteria of 34 microorganisms (A. vaginae, Gardnerella spp., L. crispatus, and P. bivia) was the best combination to identify BV in a cohort of asymptomatic pregnant women, with a sensitivity of 77.1%, and specificity of 97.0% compared with the Nugent score. The quantitative PCR in the present study responds to the limits of the Nugent score by implementing an easily reproducible quantitative assay to assess the absence of BV in pregnancy

Vaginal mucosal homeostatic response may determine pregnancy outcome in women with bacterial vaginosis a pilot study

International audienceBacterial vaginosis (BV) is considered as a trigger for an inflammatory response that could promote adverse pregnancy outcome (APO). We hypothesized that BV-related inflammation could be counterbalanced by anti-inflammatory and mucosal homeostatic responses that could participate in pregnancy outcomes.A total of 402 vaginal self-samples from pregnant women in their first trimester were screened by Nugent score. In this population, we enrolled 23 pregnant women with BV but without APO, 5 pregnant women with BV and developing APO, 21 pregnant women with intermediate flora, and 28 random control samples from pregnant women without BV or APO.BV without APO in pregnant women was associated with 28-fold interleukin-8, 5-fold interleukin-10, and 40-fold interleukin-22 increases in expression compared to controls. BV associated with APO in pregnant women shared 4-fold increase in tumor necrosis factor, 100-fold decrease in interleukin-10, and no variation in interleukin-22 expressions compared to controls. Next-generation sequencing of vaginal microbiota revealed a shift from obligate anaerobic bacteria dominance in BV without APO pregnant women to Lactobacillus dominance microbiota in BV with APO.Our results show that the anti-inflammatory and mucosal homeostatic responses to BV may determine outcome of pregnancy in the setting of BV possibly through effects on the vaginal microbiota

Nouvelles fonctions pour les produits de l’opéron ami de Pseudomonas aeruginosa: Régulation de la virulence et du biofilm bactérien.

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Characterization of the Achromobacter xylosoxidans Type VI Secretion System and Its Implication in Cystic Fibrosis

International audienceBacteria of the genus Achromobacter are environmental germs, with an unknown reservoir. It can become opportunistic pathogens in immunocompromised patients, causing bacteremia, meningitis, pneumonia, or peritonitis. In recent years, Achromobacter xylosoxidans has emerged with increasing incidence in patients with cystic fibrosis (CF). Recent studies showed that A. xylosoxidans is involved in the degradation of the respiratory function of patients with CF. The respiratory ecosystem of patients with CF is colonized by bacterial species that constantly fight for space and access to nutrients. The type VI secretion system (T6SS) empowers this constant bacterial antagonism, and it is used as a virulence factor in several pathogenic bacteria. This study aimed to investigate the prevalence of the T6SS genes in A. xylosoxidans isolated in patients with CF. We also evaluated clinical and molecular characteristics of T6SS-positive A. xylosoxidans strains. We showed that A. xylosoxidans possesses a T6SS gene cluster and that some environmental and clinical isolates assemble a functional T6SS nanomachine . A. xylosoxidans T6SS is used to target competing bacteria, including other CF-specific pathogens. Finally, we demonstrated the importance of the T6SS in the internalization of A. xylosoxidans in lung epithelial cells and that the T6SS protein Hcp is detected in the sputum of patients with CF. Altogether, these results suggest for the first time a role of T6SS in CF-lung colonization by A. xylosoxidans and opens promising perspective to target this virulence determinant as innovative theranostic options for CF management

Perylenediimide-based glycoclusters as high affinity ligands of bacterial lectins: synthesis, binding studies and anti-adhesive properties

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