Rapid identification of international multidrug-resistant Pseudomonas aeruginosa clones by multiple-locus variable number of tandem repeats analysis and investigation of their susceptibility to lytic bacteriophages
Larche J.,Center Hospitalier Of Narbonne |
Pouillot F.,Pherecydes Pharma |
Essoh C.,University Paris - Sud |
Essoh C.,French National Center for Scientific Research |
And 12 more authors.
Antimicrobial Agents and Chemotherapy | Year: 2012
The objective of this study was to determine the genetic diversity of multidrug-resistant (MDR) Pseudomonas aeruginosa strains isolated over a period of 12 months in two French hospitals and to test their susceptibility to bacteriophages. A total of 47 MDR isolates recovered from hospitalized patients were genotyped using multiple-locus variable number of tandem repeats analysis. The genotypes were distributed into five clones (including 19, 5, 5, 3, and 3 isolates, respectively) and 12 singletons. Comparison to 77 MDR strains from three other countries, and MLST analysis of selected isolates showed the predominance of international MDR clones. The larger clone, CC235, contained 59 isolates displaying different antibiotic resistance mechanisms, including the presence of the GES1, VIM-2, VIM-4, and IMP-1 β-lactamases. Three newly isolated P. aeruginosa bacteriophages were found to lyse 42 of the 44 analyzed strains, distributed into the different clonal complexes. This pilot study suggests that systematic genotyping of P. aeruginosa MDR strains could improve our epidemiological understanding of transmission at both the local (hospital) and the national level and that phage therapy could be an alternative or a complementary treatment to antibiotics for treating MDR-infected patients. Copyright © 2012, American Society for Microbiology. All Rights Reserved. Source
Bogaerts P.,Cliniques Universitaires |
Naas T.,University Paris - Sud |
El Garch F.,Cliniques Universitaires |
Cuzon G.,University Paris - Sud |
And 6 more authors.
Antimicrobial Agents and Chemotherapy | Year: 2010
During a PCR-based surveillance study of β-lactam resistance, 125 multidrug-resistant (MDR) Acinetobacter baumannii isolates were obtained from 18 hospitals in Belgium from January 2008 to December 2009. Nine GES-positive A. baumannii isolates were detected at 6 Belgian hospitals. DNA sequencing of the blaGES genes identified GES-11, GES-12, and a novel variant GES-14, which differs from GES-11 by a single amino acid substitution (Gly170Ser). All index isolates were travel associated and originated from patients transferred from Turkey (n = 2), Egypt (n = 2), and Palestinian territories (Gaza) (n = 2). A nosocomial outbreak involving three additional patients occurred in a burn unit at a single hospital. No clonal relatedness could be established between the 6 index isolates by pulsed-field gel electrophoresis (PFGE) analysis. Three different alleles (the plasmid-located blaGES-11 and bla GES-12 and a likely chromosomally located novel variant bla GES-14) were detected as part of a class 1 integron, also including the aac6′Ib and dfrA7 genes. Restriction analysis of plasmids suggests a common origin for the plasmids bearing blaGES-11 and bla GES-12. Cloning of the blaGES genes in Escherichia coli identified GES-14 as hydrolyzing imipenem, while GES-12 showed the highest specific activity against ceftazidime. This report highlights the emergence of various blaGES-like genes, especially those conferring carbapenem resistance in A. baumannii and its importation in Western Europe from Middle Eastern countries. Copyright © 2010, American Society for Microbiology. All Rights Reserved. Source
Masset H.,Catholic University of Leuven |
Hestand M.S.,Catholic University of Leuven |
Van Esch H.,Catholic University of Leuven |
Kleinfinger P.,Laboratoire Cerba |
And 8 more authors.
Human Mutation | Year: 2016
Chromoanagenesis is the process by which a single catastrophic event creates complex rearrangements confined to a single or a few chromosomes. It is usually characterized by the presence of multiple deletions and/or duplications, as well as by copy neutral rearrangements. In contrast, an array CGH screen of patients with developmental anomalies revealed three patients in which a single chromosome carries from 8 to 11 large copy number gains confined to a single chromosome or chromosomal arm, but the absence of deletions. Subsequent fluorescence in situ hybiridization and massive parallel sequencing revealed the duplicons to be clustered together in distinct locations across the altered chromosomes. Breakpoint junction sequences showed both microhomology and non-templated insertions of up to 40 bp. Hence, these patients each demonstrate a single altered chromosome of clustered insertional duplications, no deletions, and breakpoint junction sequences showing microhomology and/or non-templated insertions. These observations are difficult to reconcile with current mechanistic descriptions of chromothripsis and chromoanasynthesis. Therefore, we hypothesize those rearrangements to be of a mechanistically different origin. In addition, we suggest that large untemplated insertional sequences observed at breakpoints are driven by a non-canonical non-homologous end joining mechanism. © 2016 WILEY PERIODICALS, INC. Source
Namouchi A.,Institute Pasteur Of Tunis |
Namouchi A.,Institute Pasteur Paris |
Karboul A.,Institute Pasteur Of Tunis |
Fabre M.,Laboratoire Of Biologie Clinique |
And 2 more authors.
PLoS ONE | Year: 2013
Background:PE and PE_PGRS are two mycobateria-restricted multigene families encoding membrane associated and secreted proteins that have expanded mainly in the pathogenic species, notably the Mycobacterium tuberculosis complex (MTBC). Several lines of evidence attribute to PE and PE_PGRS genes critical roles in mycobacterial pathogenicity. To get more insight into the nature of these genes, we sought to address their evolutionary trajectories in the group of smooth tubercle bacilli (STB), the putative ancestor of the clonal MTBC.Methodology/Principal Findings:By focussing on six polymorphic STB PE/PE_PGRS genes, we demonstrate significant incongruence among single gene genealogies and detect strong signals of recombination using various approaches. Coalescent-based estimation of population recombination and mutation rates (ρ and θ, respectively) indicates that the two mechanisms are of roughly equal importance in generating diversity (ρ/θ = 1.457), a finding in a marked contrast to house keeping genes (HKG) whose evolution is chiefly brought about by mutation (ρ/θ = 0.012). In comparison to HKG, we found 15 times higher mean rate of nonsynonymous substitutions, with strong evidence of positive selection acting on PE_PGRS62 (dN/dS = 1.42), a gene that has previously been shown to be essential for mycobacterial survival in macrophages and granulomas. Imprint of positive selection operating on specific amino acid residues or along branches of PE_PGRS62 phylogenetic tree was further demonstrated using maximum likelihood- and covarion-based approaches, respectively. Strikingly, PE_PGR62 proved highly conserved in present-day MTBC strains.Conclusions/Significance:Overall the data indicate that, in STB, PE/PE_PGRS genes have undergone a strong diversification process that is speeded up by recombination, with evidence of positive selection. The finding that positive selection involved an essential PE_PGRS gene whose sequence appears to be driven to fixation in present-day MTBC strains lends further support to the critical role of PE/PE_PGRS genes in the evolution of mycobacterial pathogenicity. © 2013 Namouchi et al. Source
Anaphylactic shock to human insulin: Follow-up of a desensitization protocol by basophil activation test [Choc anaphylactique à l'insuline humaine recombinante: suivi d'un protocole d'accoutumance par tests d'activation des basophiles]
Luyasu S.,Service de Reanimation medicale |
Hougardy N.,Laboratoire Of Biologie Clinique |
Hasdenteufel F.,Nancy University Hospital Center |
Jacquenet S.,Genclis SAS |
And 3 more authors.
Revue de Medecine Interne | Year: 2011
Introduction: Despite the occurrence of a severe allergic reaction including an anaphylactic shock, a drug may remain essential and impossible to replace. This may be the case of insulin in a diabetic patient. We describe the case of an anaphylactic shock to human insulin in whom a desensitization protocol was successfully achieved. Case report: A 50-year-old type 2 diabetic man presented one year after initiation of the insulin therapy an anaphylactic shock following the subcutaneous administration of a human insulin containing protamine (Insulatard®). A desensitization protocol to human insulin was performed and allowed to use two human insulin analogues containing no protamine (asparte and glargine), with a two-year event-free follow-up. Positive skin tests with insulin and protamine, and the presence of insulin specific IgE were evidenced of an IgE-mediated mechanism. Desensitization was monitored by skin tests, Maunsell's test, measurement of specific IgE and IgG4, and the basophil activation test. The decrease of basophil sensitivity to insulin is an early marker for tolerance induction. Conclusion: The effectiveness of the desensitization to human insulin underlines the importance to define the modalities of such desensitization protocol and of the monitoring of the tolerance induction. © 2010 Société nationale française de médecine interne (SNFMI). Source