D Izard

Centre Hospitalier Régional Universitaire de Lille, Lille, Nord-Pas-de-Calais, France

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Publications (128)183.71 Total impact

  • Pascal Sonnet · Daniel Izard · Catherine Mullié
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    ABSTRACT: To assess the prevalence of efflux-driven fluoroquinolone (FQ) resistance in recent clinical isolates of Pseudomonas aeruginosa, a worrisome and often hospital-acquired pathogen, 115 unique strains were collected over a 5-month period, of which 27 and 33 had decreased susceptibility to ciprofloxacin (CIP) and levofloxacin (LVX), respectively. The MIC(50) (minimum inhibitory concentration for 50% of the organisms) was 16 μg/mL for both FQs. The efflux pump inhibitors (EPIs) phenylalanine-arginine-β-naphthylamide (PAβN) and 1-(1-naphthylmethyl)-piperazine (NMP) were then used to evaluate their efficacy in reducing CIP and LVX MICs. NMP did not significantly modify CIP MICs, whilst PAβN resulted in MIC(50) values of 2 μg/mL and 0.125 μg/mL for CIP and LVX, respectively. With the addition of PAβN, susceptibility to CIP and LVX was recovered in 6 (22.2%) and 31 (93.9%) strains, respectively. The best combination to reverse FQ resistance in this set of strains was LVX with PAβN. The results of this study show that the effect of an EPI is not only dependent on the species on which it is used but also on the molecule associated with it. Therefore, the design of an EPI equally efficient on all resistance-nodulation-cell division (RND) efflux pumps appears to be difficult and, from a practical point of view, if an EPI is developed for clinical use, the efficiency of its combination with a definite molecule should be assessed carefully against a wide range of clinical isolates to evaluate the real benefit of this combination.
    No preview · Article · Jan 2012 · International journal of antimicrobial agents
  • D. Izard · F. Gavini · P. A. Trinel · H. Leclerc

    No preview · Article · Feb 2011 · Canadian Journal of Microbiology
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    ABSTRACT: Phenetic (numerical analysis) and genetic (DNA–DNA hybridization) studies were carried out on strains belonging or related to the species Escherichia coli. They have shown the diversity of its phenotypes, by the presence of plasmidic characters (citrate+, urease+, H2S+, tetrathionate reductase+, raffinose+, and saccharose+). New strains related phenetically to E. coli are also individualized. They showed less than 30% DNA relatedness with E. coli. A new definition of E. coli is presented.
    Full-text · Article · Feb 2011 · Canadian Journal of Microbiology
  • C.J. Mullié · D. Izard · M.-B. Romond
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    ABSTRACT: Mother's milk remains the gold standard for the nutrition of human neonates.Thanks to its adaptable biochemical and immunological composition, mother's milkallows for an optimal development of the intestinal microflora, especially by promotingthe implantation and growth of some of the so-called health beneficial bacteria:bifidobacteria. When bifidobacteria are dominant in the intestinal flora, they are thoughtto help preventing gastrointestinal disorders, repress a potentially harmful proliferation ofother intestinal bacteria and stimulate the priming of the neonate's intestinal immunesystem. This is why, among other research trends, the latest infant formulas areattempting to reproduce this bifidogenic effect of mother's milk through various wayssuch as the addition of exogenous bifidobacteria and/or of prebiotics (specificcarbohydrate substrates promoting the growth of indigenous intestinal bifidobacteria).We will first review the beneficial effects of mother's milk and those putatively related toindigenous bacteria. The probiotic (feeding of live bifidobacteria) and prebiotic (feedingof specific carbohydrates) approaches to increase intestinal bifidobacteria will also bedefined. Then, we will focus on prebiotics and on a novel approach to promoteindigenous intestinal bifidobacteria: the use of an infant formula containing products of milk fermentation by Bifidobacterium breve strain C50. These fermentation productshave previously been shown to have a bifidogenic effect on indigenous bifidobacteria,thus acting like prebiotics. We will compare the effect of this formula on the intestinalmicroflora establishment to the ones of mother's milk and of a standard formula. We willalso deal with the issue of specifically stimulating the growth of certain species ofindigenous bifidobacteria, as some bacterial species belonging to this genus (e.g.,Bifidobacterium adolescentis) have been shown to be linked with immunologicalconditions in neonates and young children such as atopic dermatitis.
    No preview · Article · Jan 2010
  • M Hamze · F Dabboussi · D Izard

    No preview · Article · Jan 2010

  • No preview · Article · Jan 2010 · Journal Europeen d'Hydrologie
  • M. Elomari · L. Coroler · D. Izard · H. Leclerc

    No preview · Article · Jan 2010 · Journal Europeen d'Hydrologie

  • No preview · Article · Jan 2010 · Journal Europeen d'Hydrologie
  • L. Coroler · M. Elomari · D. Izard · H. Leclerc

    No preview · Article · Jan 2010 · Journal Europeen d'Hydrologie
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    ABSTRACT: This study aimed at determining the contribution of intestinal bifidobacteria to the immune system activation using widely distributed galectins as markers of immune cell homoeostasis. In human flora-associated mice, bacteria were enumerated in the gut, blood, spleen, liver and lungs, while the expression of galectin-1 (Gal-1) and galectin-3 (Gal-3) was estimated by PCR in the intestine and real-time quantitative PCR in the other organs. Gal-1 and -3 were rarely expressed in the intestine. In blood, only Gal-1 was expressed while both galectins were expressed in all other organs. A high prevalence of colonic bifidobacteria was associated with a lower expression of both pulmonary galectins, whose levels negatively correlated with bifidobacterial counts. Caecal bifidobacterial counts also negatively correlated with pulmonary Gal-3 mRNA levels. The spleen was the only organ showing an upregulation of Gal-1 expression related to its bacterial contamination. However, this upregulation was only observed when bifidobacteria were not detected in the colon. A putative mechanism explaining the reduced expression of galectins when bifidobacteria highly colonize the mouse intestine could be that, by reducing the bacterial translocation, bifidobacteria also lead to a decreased blood concentration of substances produced by intestinal bacteria.
    Preview · Article · Jan 2009 · FEMS Immunology & Medical Microbiology
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    ABSTRACT: The aim of this work was to investigate the possible role of the intestinal anaerobic flora (especially bifidobacteria) in regulating bacterial translocation (BT) which can be defined as the passage of intestinal microbes through the mucosa to internal organs. Default in BT regulation concurs with pathogenesis of sepsis in various human conditions, such as acute pancreatitis, cirrhosis, necrotising enterocolitis or multiple organ failure. The intestinal flora was studied in human flora associated mice (HF mice) and BT was quantified in Peyer's patches (PP), blood, spleen, liver and lungs. HF mice displayed a heterogenic intestinal colonisation with bifidobacteria. High colonisation of both caecum and colon by bifidobacteria led to a poorer bacterial contamination of blood, liver and lungs. Moreover, ileal, caecal and colonic bifidobacterial counts negatively correlated with the bacterial dissemination (number of contaminated organs per mouse). In contrast, Bacteroides fragilis group counts positively correlated with bacteraemia, lungs contamination or bacterial dissemination. Additionally, clostridia localised in the colon affected bacterial uptake by PP and lungs contamination as indicated by positive correlations between bacterial populations in these respective locations. These results indicate that bifidobacteria, when established in high counts, reduced BT to liver, blood and lungs, whereas B. fragilis group favoured the bacterial passage. Clostridia established in the distal ileum also seemed to favour BT to lungs. The manipulation of the bacterial flora to optimise the regulatory effect on BT should therefore focus on the selective promotion of bifidobacteria and avoid an increase in potentially detrimental populations such as B. fragilis group and clostridia.
    No preview · Article · Mar 2008 · Anaerobe
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    ABSTRACT: One hundred and forty-four fluorescent pseudomonad strains isolated from various environments (soil, water, plant rhizosphere, hospital) and received as Pseudomonas putida (83 strains), P. putida biovar A (49 strains), P. putida biovar B (10 strains) and P. putida biovar C (2 strains), were analysed by the pyoverdine-isoelectrofocusing and pyoverdine-mediated iron uptake methods of siderotyping. Both methods demonstrated a great diversity among these strains, which could be subdivided into 35 siderovars. Some siderovars specifically included strains that have subsequently been transferred to well-defined Pseudomonas species, e.g. Pseudomonas monteilii or Pseudomonas mosselii, or which could be related by their siderotype to Pseudomonas jessenii or Pseudomonas mandelii. Other siderovars included strains sharing a high level of DNA-DNA relatedness (>70%), thus demonstrating that siderotyping could easily circumscribe strains at the species level. However, a group of seven strains, including the type strain, P. putida ATCC 12633T, were allocated into four siderovars, despite sharing DNA-DNA relatedness values of higher than 70 %. Interestingly, the strong genomic relationships between these seven strains were supported by the structural relationships among their pyoverdines, thus reflecting their phylogenetic affinities. These results strongly support the view that pyoverdine-based siderotyping could be used as a powerful tool in Pseudomonas taxonomy.
    Preview · Article · Nov 2007 · International Journal of Systematic and Evolutionary Microbiology
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    C Mullié · M B Romond · D Izard
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    ABSTRACT: Twenty-one healthy bottle-fed infants were screened monthly (1-4 months) for bifidobacteria in their stools. Bifidobacteria were detected by culture and isolates specified by PCR. Alternatively, direct PCR in undiluted fecal suspensions was carried out for detection of bifidobacteria under the cultural detection level. All infants harbored cultivable bifidobacteria throughout the study period. Beerens medium was shown to permit a better recovery of bifidobacteria than MRS and horse blood Columbia agar. Direct PCR detection proved valuable in detecting species for which no cultural isolate could be recovered since the species were under the cultural detection level. B. bifidum, B. longum-infantis and B. breve were confirmed as dominant and stable species in infant stools while B. adolescentis and B. catenulatum group exhibited unstable colonization profiles. A trend towards B. breve decrease began at month 3 while carriage of the B. catenulatum group and B. adolescentis was rising. This observation warrants further analysis to assess a possible switch occurring at month 3 in bottle-fed infants, between so-called infant and adult bifidobacterial species.
    Full-text · Article · Feb 2006 · Folia Microbiologica
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    ABSTRACT: We reported a case of lombar spondylodiscitis caused by Salmonella enteritica serotype Typhi in an immunocompetent patient. Salmonella is a rare causative agent of spondylodiscitis. Early bacteriological diagnosis is essential to avoid longterm sequelae.
    No preview · Article · Sep 2005 · Annales de biologie clinique
  • M Hamze · F Dabboussi · D Izard
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    ABSTRACT: Four hundred and sixty-four Pseudomonas aeruginosa strains were isolated in northern Lebanon at the Islami Hospital Microbiology department, in Tripoli. The purpose of this study was to evaluate the susceptibility of these strains to antibiotics, to compare this susceptibility according to the nature of the sample and the year of sampling. The results show that urinary samples were the most frequent (39.3%), followed by wound samples (21.2%), and ear samples (16.5%). The average rate of susceptible strains was 39.8% to ticarcillin, 56.9% to piperacillin, 58.2% to piperacillin + tazobactam, 74.1% to imipenem, 63.3% to ceftazidime, 60.4% to cefepime, 62.1% to aztreonam, 60.3% to netilmicin, 57.5% to gentamicin, 62.2% to tobramycin, 69% to amikacin, 100% to colistin, 45.4% to pefloxacin and ofloxacin, 57.7% to ciprofloxacin and 1.3% to rifampicin. The study showed that the strains isolated from pulmonary secretions were the most resistant to antibiotics.
    No preview · Article · Aug 2004 · Médecine et Maladies Infectieuses
  • M. Hamze · F. Dabboussi · D. Izard
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    ABSTRACT: Four hundred and sixty-four Pseudomonas aeruginosa strains were isolated in northern Lebanon at the Islami Hospital Microbiology department, in Tripoli. The purpose of this study was to evaluate the susceptibility of these strains to antibiotics, to compare this susceptibility according to the nature of the sample and the year of sampling. The results show that urinary samples were the most frequent (39.3%), followed by wound samples (21.2%), and ear samples (16.5%). The average rate of susceptible strains was 39.8% to ticarcillin, 56.9% to piperacillin, 58.2% to piperacillin + tazobactam, 74.1% to imipenem, 63.3% to ceftazidime, 60.4% to cefepime, 62.1% to aztreonam, 60.3% to netilmicin, 57.5% to gentamicin, 62.2% to tobramycin, 69% to amikacin, 100% to colistin, 45.4% to pefloxacin and ofloxacin, 57.7% to ciprofloxacin and 1.3% to rifampicin. The study showed that the strains isolated from pulmonary secretions were the most resistant to antibiotics.
    No preview · Article · Jul 2004 · Médecine et Maladies Infectieuses
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    ABSTRACT: Within a few years bacteriological knowledge on Burkholderia cepacia species has progressed considerably. Within bacterial classification (taxonomy), B. cepacia gathers eight species and one species on standby of nomenclature (genomovar VI); the whole of these species constitutes the "B. cepacia complex" or B. cepacia "sensu lato" and the denomination B. cepacia "sensu stricto" is attributed to the genomovar I. These new data call into question the knowledge on the clinic and the epidemiology of B. cepacia "sensu lato" infection in the course of cystic fibrosis. Among these newly described species, B. cenocepacia (formerly genomovar III) and B. multivorans (formerly genomovar II) are the most frequent species and together they represent more than 90% of infections associated to "B. cepacia complex" in the course of cystic fibrosis. B. cenocepacia is often associated to the "cepacia syndrome" which is characterized as a fatal necrotizing pneumonia with bacteremia. The progress of molecular epidemiology allowed the description of bacterial clones of which some are highly transmissible from person-to-person. Their distribution varies according to the species and the geography. The identification of these new species appears particularly difficult and, by the fact, the data on taxonomy and molecular epidemiology can be provided only by highly specialized reference centers.
    No preview · Article · May 2004 · Archives de Pédiatrie
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    ABSTRACT: Within a few years bacteriological knowledge on Burkholderia cepacia species has progressed considerably. Within bacterial classification (taxonomy), B. cepacia gathers eight species and one species on standby of nomenclature (genomovar VI); the whole of these species constitutes the “B. cepacia complex” or B. cepacia “sensu lato” and the denomination B. cepacia “sensu stricto” is attributed to the genomovar I. These new data call into question the knowledge on the clinic and the epidemiology of B. cepacia “sensu lato” infection in the course of cystic fibrosis. Among these newly described species, B. cenocepacia (formerly genomovar III) and B. multivorans (formerly genomovar II) are the most frequent species and together they represent more than 90% of infections associated to “B. cepacia complex” in the course of cystic fibrosis. B. cenocepacia is often associated to the “cepacia syndrome” which is characterized as a fatal necrotizing pneumonia with bacteremia. The progress of molecular epidemiology allowed the description of bacterial clones of which some are highly transmissible from person-to-person. Their distribution varies according to the species and the geography. The identification of these new species appears particularly difficult and, by the fact, the data on taxonomy and molecular epidemiology can be provided only by highly specialized reference centers.
    No preview · Article · Apr 2004 · Archives de Pédiatrie
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    ABSTRACT: Three multiplex polymerase chain reactions (PCRs) targeted on Bifidobacterium and related species were designed to identify human species. The selected primers yielded amplified products of various sizes, each specific for a species. Three to four pairs were gathered in one PCR reaction and their specificity under multiplex conditions was confirmed using DNA from 26 reference strains. Using this technique on unidentified faecal strains, B. bifidum, B. longum and B. breve species were commonly recovered in infants while B. adolescentis, B. catenulatum/B. pseudocatenulatum continuum and B. longum species were predominant in adults. Thus, a single PCR can provide the assignment of a strain to one these species, reducing the number of PCR reactions and hands-on time for the identification of human isolates of bifidobacteria. Moreover, this technique is also applicable for the in situ detection of bifidobacteria in DNA extracts from human stools.
    Preview · Article · Jun 2003 · FEMS Microbiology Letters
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    Monzer Hamze · Fouad Dabboussi · Daniel Izard
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    ABSTRACT: The purpose of this study was to assess the epidemiology of local enterobacterial susceptibility to antibiotics. Between 1 January, 1998, and 31 December, 2001, we studied the sensitivity of 2,238 Enterobacteria to 26 different antibiotic agents in northern Lebanon, in the Microbiology department and Laboratory of the Islami Hospital, Tripoli, Lebanon. We used the diffusion disk method and complied with the guidelines of the French Microbiology Society antibiogram committee. Urinary samples were the most frequent source (67.5%), followed by blood cultures (12.7%). The dominant species in blood cultures was S. typhi (44.7%). We found 194 strains that produced extended-spectrum beta lactamases (ESBL), with the highest prevalence in Serratia spp. (44.3%), followed by Klebsiella pneumoniae (23.7%), Escherichia coli (20.7%) and Klebsiella oxytoca (11.3%). The global susceptibility of these strains to aminopenicillin was 15%; it reached 30% when combined with clavulanic acid. Susceptibility of the ESBL strains to these agents was 0%. The global susceptibility (and that of the ESBL strains, when greater than 0%) to other antibiotics was as follows: ticarcillin 38.5%, piperacillin 38.5%, piperacillin-tazobactam 88% (64%), imipenem 99.4%, (100%), cefalexin 41%, cefoxitin 65% (40.3%), cefuroxime 75%, amikacin 89%, chloramphenicol 30%, gentamicin 78% (42%), tetracycline 28% (16%), minocycline 30% (18.4%), colistin 67% (75%), nitrofuran 40% (45%), cotrimoxazol 40% (13%), nalidixic acid 53% (5.6%), pefloxacin 63% (23%), ciprofloxacin 71% (39%), and levofloxacin 72% (47%).
    Preview · Article · Apr 2003 · Sante (Montrouge, France)

Publication Stats

2k Citations
183.71 Total Impact Points

Institutions

  • 1999-2012
    • Centre Hospitalier Régional Universitaire de Lille
      Lille, Nord-Pas-de-Calais, France
  • 2006
    • Lille Catholic University
      Lille, Nord-Pas-de-Calais, France
  • 1982-2002
    • University of Lille Nord de France
      Lille, Nord-Pas-de-Calais, France
  • 1988-1990
    • French Institute of Health and Medical Research
      Lutetia Parisorum, Île-de-France, France
  • 1981-1990
    • Unité Inserm U1077
      Caen, Lower Normandy, France
  • 1979-1981
    • Institut Pasteur de Lille
      Lille, Nord-Pas-de-Calais, France