Intestinal colonization due to Escherichia coli ST131: Risk factors and prevalence

Background Escherichia coli sequence type 131 (ST131) is a successful clonal group that has dramatically spread during the last decades and is considered an important driver for the rapid increase of quinolone resistance in E. coli. Methods Risk factors for rectal colonization by ST131 Escherichia coli (irrespective of ESBL production) were investigated in 64 household members (18 were colonized) and 54 hospital contacts (HC; 10 colonized) of 34 and 30 index patients with community and nosocomial infection due to these organisms, respectively, using multilevel analysis with a p limit of < 0.1. Result Colonization among household members was associated with the use of proton-pump inhibitors (PPI) by the household member (OR = 3.08; 95% CI: 0.88–10.8) and higher age of index patients (OR = 1.05; 95% CI; 1.01–1.10), and among HC, with being bed-ridden (OR = 21.1; 95% CI: 3.61–160.0) and having a urinary catheter (OR = 8.4; 95% CI: 0.87–76.9). Conclusion Use of PPI and variables associated with higher need of person-to-person contact are associated with increased risk of rectal colonization by ST131. These results should be considered for infection control purposes.Plan Nacional de I + D + i 2013-2016Ministerio de Economía y Competitividad (España)European Development Regional Fund REIPI RD12/0015/0010 REIPI RD16/0016/0001Instituto de Salud Carlos III 070190 AC16/000076-MODERN AC16/AC16/00072-ST131TSJunta de Andalucía CTS5259 CTS21

A New Fluorescent Sensor Based on 1H-pyrazolo[3,4-b]quinoline Skeleton. Part 2

A novel fluorescent dye bis-(pyridin-2-yl-methyl)-(1,3,4-triphenyl-1H-pyrazolo[3,4-b]quinolin-6-ylmethyl)-amine (P1) has been synthesized and investigated by means of steady state and time-resolved fluorescence techniques. This compound acts as sensor for fluorescence detection of small inorganic cations (lithium, sodium, barium, magnesium, calcium, and zinc) in highly polar solvents such as acetonitrile. The mechanism which allows application of this compound as sensor is an electron transfer from the electron-donative part of molecule (amine) to the acceptor part (pyrazoloquinoline derivative), which is retarded upon complexation of the electro-donative part by inorganic cations. The binding constants are strongly dependent on the charge density of the analyzed cations. The 2/1 complexes of P1 with Zn++ and Mg++ cations posses large binding constants. Moreover, in the presence of these cations a significant bathochromic shift of fluorescence is observed. The most probable explanation of such behaviour is the formation of intramolecular excimer. This is partially supported by the quantum chemical calculations

Efflux Pump, the Masked Side of ß-Lactam Resistance in Klebsiella pneumoniae Clinical Isolates

International audienceBACKGROUND: Beta-lactamase production and porin decrease are the well-recognized mechanisms of acquired beta-lactam resistance in Klebsiella pneumoniae isolates. However, such mechanisms proved to be absent in K. pneumoniae isolates that are non susceptible to cefoxitin (FOX) and susceptible to amoxicillin+clavulanic acid in our hospital. Assessing the role of efflux pumps in this beta-lactam phenotype was the aim of this study. METHODOLOGY/FINDINGS: MICs of 9 beta-lactams, including cloxacillin (CLX), and other antibiotic families were tested alone and with an efflux pump inhibitor (EPI), then with both CLX (subinhibitory concentrations) and EPI against 11 unique bacteremia K. pneumoniae isolates displaying the unusual phenotype, and 2 ATCC strains. CLX and EPI-dose dependent effects were studied on 4 representatives strains. CLX MICs significantly decreased when tested with EPI. A similar phenomenon was observed with piperacillin+tazobactam whereas MICs of the other beta-lactams significantly decreased only in the presence of both EPI and CLX. Thus, FOX MICs decreased 128 fold in the K. pneumoniae isolates but also 16 fold in ATCC strain. Restoration of FOX activity was CLX dose-dependent suggesting a competitive relationship between CLX and the other beta-lactams with regard to their efflux. For chloramphenicol, erythromycin and nalidixic acid whose resistance was also due to efflux, adding CLX to EPI did not increase their activity suggesting differences between the efflux process of these molecules and that of beta-lactams. CONCLUSION: This is the first study demonstrating that efflux mechanism plays a key role in the beta-lactam susceptibility of clinical isolates of K. pneumoniae. Such data clearly evidence that the involvement of efflux pumps in beta-lactam resistance is specially underestimated in clinical isolates

Propolis can potentialise the anti-adhesion activity of proanthocyanidins on uropathogenic Escherichia coli in the prevention of recurrent urinary tract infections

<p>Abstract</p> <p>Background</p> <p><it>Escherichia coli</it>, the main bacteria found in recurrent urinary tract infections (UTI), is now frequently resistant to several currently used antibiotic treatments making new solutions essential. In this study, we evaluated the association propolis and proanthocyanidins type A to reduce bacterial anti-adhesion activity of <it>E. coli </it>on urothelial cells.</p> <p>Results</p> <p>This first double-blind, randomized, cross-over human trial included 5 volunteers that followed 6 different regimens with or without variable doses of cranberry and propolis with a washout period of at least 1 week between each regimen. Urine samples were collected at 0 h, 4-6 h, 12 h and 24 h after cranberry plus propolis or placebo capsule consumption. In vivo urinary bacterial anti-adhesion activity was assessed with a bioassay (a human T24 epithelial cell-line assay) and an in vivo <it>Caenorhabditis elegans </it>model. HPLC-PDA-MS was used to detect propolis and cranberry compounds in urine. Bioassays indicated significant bacterial anti-adhesion activity in urine collected from volunteers who had consumed cranberry plus propolis powder compared to placebo (<it>p </it>< 0.001). This inhibition was clearly dose-dependent, increasing with the amount of PACs and propolis equivalents consumed in each regimen. Results suggested that propolis had an additional effect with PACs and prevent a bacterial anti-adhesion effect over 1 day. An in vivo model showed that the <it>E. coli </it>strain presented a reduced ability to kill <it>C. elegans </it>after their growth in urine samples of patients who took cranberry plus propolis capsules. HPLC confirmed that propolis is excreted in urine.</p> <p>Conclusions</p> <p>This study presents an alternative to prevent recurrent UTI. Administration of PACs plus propolis once daily offers some protection against bacterial adhesion, bacterial multiplication and virulence in the urinary tract, representing an interesting new strategy to prevent recurrent UTI.</p

Les essais

Après les montages électromécaniques vient le temps des essais. Des milliers de composants, livrés par plusieurs centaines de fournisseurs, sont reliés entre eux par des réseaux totalisant des dizaines de kilomètres de câbles électriques... Il s'agit de mettre progressivement en vie cet assemblage extraordinairement complexe et de vérifier, à travers quelque 2 000 procédures d'exécution, que chaque appareil et système fonctionne selon les spécifications prévues

Characterisation of resistance to branched broomrape, Phelipanche ramosa, in winter oilseed rape

a b s t r a c t Over the past decade, Phelipanche ramosa, a weedy parasitic plant (broomrape), has been increasingly infesting winter oilseed rape (WOSR) fields in France. Elite WOSR lines have shown different responses in P. ramosa infested fields, suggesting that genetic variability might be available for breeding programmes targeting broomrape resistance. Ten WOSR genotypes selected for their contrasting response in field experiments were analysed using mini-rhizotron and greenhouse co-culture experiments to determine the components of resistance to broomrape. Partial resistance was revealed at three developmental stages of the parasitic plant. First, at the germination stage, parasite attachment to the roots of some WOSR lines was limited and associated with a low rate of parasite seed germination. This mechanism of parasite avoidance could nevertheless be suppressed under high infestation in mini-rhizotron and greenhouse conditions. Second, at the root attachment stage, limited parasite attachment was observed in mini-rhizotron conditions under low and high infestation, and in greenhouse conditions. Third, after successful parasite attachment, some WOSR genotypes retarded and even disturbed the growth of tubercles, minimising and delaying parasite emergence from the soil. Although the exact mechanisms limiting parasite attachment and tubercle development require further investigation, our findings suggest that, by cumulating various resistance traits in new genotypes to enhance effectiveness and potential durability of resistance, breeding could be a promising control strategy in WOSR

Characterisation of resistance to branched broomrape, Phelipanche ramosa, in winter oilseed rape

International audienceOver the past decade, Phelipanche ramosa, a weedy parasitic plant (broomrape), has been increasingly infesting winter oilseed rape (WOSR) fields in France. Elite WOSR lines have shown different responses in P. ramosa infested fields, suggesting that genetic variability might be available for breeding programmes targeting broomrape resistance. Ten WOSR genotypes selected for their contrasting response in field experiments were analysed using mini-rhizotron and greenhouse co-culture experiments to determine the components of resistance to broomrape. Partial resistance was revealed at three developmental stages of the parasitic plant. First, at the germination stage, parasite attachment to the roots of some WOSR lines was limited and associated with a low rate of parasite seed germination. This mechanism of parasite avoidance could nevertheless be suppressed under high infestation in mini-rhizotron and greenhouse conditions. Second, at the root attachment stage, limited parasite attachment was observed in mini-rhizotron conditions under low and high infestation, and in greenhouse conditions. Third, after successful parasite attachment, some WOSR genotypes retarded and even disturbed the growth of tubercles, minimising and delaying parasite emergence from the soil. Although the exact mechanisms limiting parasite attachment and tubercle development require further investigation, our findings suggest that, by cumulating various resistance traits in new genotypes to enhance effectiveness and potential durability of resistance, breeding could be a promising control strategy in WOSR. (C) 2012 Elsevier Ltd. All rights reserved