Acinetobacter Baumannii

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Patrice Nordmann - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of resazurin based rapid test to detect colistin resistance in Acinetobacter Baumannii isolates
    European Journal of Clinical Microbiology & Infectious Diseases, 2019
    Co-Authors: Julija Germ, Laurent Poirel, Patrice Nordmann, Tjasa Cerar Kisek, Vesna Cvitkovic Spik, Katja Seme, Manica Mueller Premru, Tatjana Lejko Zupanc, Mateja Pirs
    Abstract:

    : Acinetobacter Baumannii primarily causes colonization, yet it can be an opportunistic pathogen associated with hospital-acquired infections. Many countries report rapid spread of carbapenem-resistant Acinetobacter Baumannii (CRAb) which limits treatment options, with colistin frequently being the last line treatment option. The aim of our study was to evaluate a recently developed rapid method, namely the Rapid ResaPolymyxin test, for detection of colistin resistance (ColR) in Acinetobacter Baumannii. This test was used for rapid screening of colistin resistance in a clinical setting where there is endemicity of CRAb isolates. A total of 82 A. Baumannii clinical isolates were included in the evaluation. The majority of them were resistant to carbapenems (75/82, 91.5%). A total of 37 isolates (45.1%) were resistant to colistin, all being resistant to carbapenems. None of the ColR isolates carried the plasmid-mediated mcr-1 to -5 genes. The Rapid ResaPolymyxin NP test reached a 95.1% categorical agreement with results of reference broth microdilution method, with 93.3% sensitivity and specificity, and positive and negative predictive values being respectively at 92.3% and 97.7%. The Rapid ResaPolymyxin NP test performed well on our collection of clinical and surveillance CRAb isolates from the Central Slovenia region. The test is inexpensive and easy to integrate into laboratory workflow. The main value of the test is rapid categorization of susceptibility and resistance which has important implications with respect to the treatment strategy as well as the infection control measures.

  • tn125 related acquisition of blandm like genes in Acinetobacter Baumannii
    Antimicrobial Agents and Chemotherapy, 2012
    Co-Authors: Laurent Poirel, Remy A Bonnin, Anne Boulanger, Jacques Schrenzel, Martin Kaase, Patrice Nordmann
    Abstract:

    A multidrug-resistant Acinetobacter Baumannii isolate recovered from a patient hospitalized in Switzerland after a transfer from Serbia produced the NDM-1 carbapenemase. The bla(NDM-1) gene was part of a chromosomally located Tn125 composite transposon bracketed by two copies of the same insertion sequence, ISAba125. This transposon was also associated with the acquisition and expression of the bla(NDM-2) gene in an A. Baumannii isolate in Germany. Tn125 appears to be the main vehicle for dissemination of bla(NDM) genes in that species.

  • functional analysis of insertion sequence isaba1 responsible for genomic plasticity of Acinetobacter Baumannii
    Journal of Bacteriology, 2009
    Co-Authors: Pauline D Mugnier, Laurent Poirel, Patrice Nordmann
    Abstract:

    ISAba1 is an insertion sequence that is widely distributed in Acinetobacter Baumannii. We demonstrated here that ISAba1 and the composite transposon Tn2006 are capable of transposition, generating 9-bp target site duplications. The expression of the ISAba1 transposase-encoding gene was downregulated by translational frameshifting.

  • worldwide dissemination of the blaoxa 23 carbapenemase gene of Acinetobacter Baumannii
    Emerging Infectious Diseases, 2009
    Co-Authors: Pauline D Mugnier, Laurent Poirel, Thierry Naas, Patrice Nordmann
    Abstract:

    To assess dissemination of OXA-23–producing strains of Acinetobacter Baumannii, we obtained 20 carbapenem-resistant, OXA-23–producing isolates from different regions. Their clonal relationship was assessed by pulsed-field gel electrophoresis and multilocus sequence typing. We identified 8 sequence types, including 4 novel types. All except 2 strains belonged to 2 main European clonal lineages. The blaOXA-23 gene was either located on the chromosome or on plasmids and associated with 4 genetic structures.

  • genetics and expression of the carbapenem hydrolyzing oxacillinase gene blaoxa 23 in Acinetobacter Baumannii
    Antimicrobial Agents and Chemotherapy, 2007
    Co-Authors: Stephane Corvec, Laurent Poirel, Thierry Naas, Henri Drugeon, Patrice Nordmann
    Abstract:

    The genetic structures surrounding the plasmid-carried blaOXA-23 oxacillinase gene, encoding resistance to carbapenems, were studied in Acinetobacter Baumannii. ISAba1 and the novel element ISAba4 were detected upstream of the blaOXA-23 gene, providing promoter sequences for its expression. These insertion elements were likely involved in transposition processes at the origin of acquisition of this β-lactamase gene.

Laurent Poirel - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of resazurin based rapid test to detect colistin resistance in Acinetobacter Baumannii isolates
    European Journal of Clinical Microbiology & Infectious Diseases, 2019
    Co-Authors: Julija Germ, Laurent Poirel, Patrice Nordmann, Tjasa Cerar Kisek, Vesna Cvitkovic Spik, Katja Seme, Manica Mueller Premru, Tatjana Lejko Zupanc, Mateja Pirs
    Abstract:

    : Acinetobacter Baumannii primarily causes colonization, yet it can be an opportunistic pathogen associated with hospital-acquired infections. Many countries report rapid spread of carbapenem-resistant Acinetobacter Baumannii (CRAb) which limits treatment options, with colistin frequently being the last line treatment option. The aim of our study was to evaluate a recently developed rapid method, namely the Rapid ResaPolymyxin test, for detection of colistin resistance (ColR) in Acinetobacter Baumannii. This test was used for rapid screening of colistin resistance in a clinical setting where there is endemicity of CRAb isolates. A total of 82 A. Baumannii clinical isolates were included in the evaluation. The majority of them were resistant to carbapenems (75/82, 91.5%). A total of 37 isolates (45.1%) were resistant to colistin, all being resistant to carbapenems. None of the ColR isolates carried the plasmid-mediated mcr-1 to -5 genes. The Rapid ResaPolymyxin NP test reached a 95.1% categorical agreement with results of reference broth microdilution method, with 93.3% sensitivity and specificity, and positive and negative predictive values being respectively at 92.3% and 97.7%. The Rapid ResaPolymyxin NP test performed well on our collection of clinical and surveillance CRAb isolates from the Central Slovenia region. The test is inexpensive and easy to integrate into laboratory workflow. The main value of the test is rapid categorization of susceptibility and resistance which has important implications with respect to the treatment strategy as well as the infection control measures.

  • tn125 related acquisition of blandm like genes in Acinetobacter Baumannii
    Antimicrobial Agents and Chemotherapy, 2012
    Co-Authors: Laurent Poirel, Remy A Bonnin, Anne Boulanger, Jacques Schrenzel, Martin Kaase, Patrice Nordmann
    Abstract:

    A multidrug-resistant Acinetobacter Baumannii isolate recovered from a patient hospitalized in Switzerland after a transfer from Serbia produced the NDM-1 carbapenemase. The bla(NDM-1) gene was part of a chromosomally located Tn125 composite transposon bracketed by two copies of the same insertion sequence, ISAba125. This transposon was also associated with the acquisition and expression of the bla(NDM-2) gene in an A. Baumannii isolate in Germany. Tn125 appears to be the main vehicle for dissemination of bla(NDM) genes in that species.

  • functional analysis of insertion sequence isaba1 responsible for genomic plasticity of Acinetobacter Baumannii
    Journal of Bacteriology, 2009
    Co-Authors: Pauline D Mugnier, Laurent Poirel, Patrice Nordmann
    Abstract:

    ISAba1 is an insertion sequence that is widely distributed in Acinetobacter Baumannii. We demonstrated here that ISAba1 and the composite transposon Tn2006 are capable of transposition, generating 9-bp target site duplications. The expression of the ISAba1 transposase-encoding gene was downregulated by translational frameshifting.

  • worldwide dissemination of the blaoxa 23 carbapenemase gene of Acinetobacter Baumannii
    Emerging Infectious Diseases, 2009
    Co-Authors: Pauline D Mugnier, Laurent Poirel, Thierry Naas, Patrice Nordmann
    Abstract:

    To assess dissemination of OXA-23–producing strains of Acinetobacter Baumannii, we obtained 20 carbapenem-resistant, OXA-23–producing isolates from different regions. Their clonal relationship was assessed by pulsed-field gel electrophoresis and multilocus sequence typing. We identified 8 sequence types, including 4 novel types. All except 2 strains belonged to 2 main European clonal lineages. The blaOXA-23 gene was either located on the chromosome or on plasmids and associated with 4 genetic structures.

  • genetics and expression of the carbapenem hydrolyzing oxacillinase gene blaoxa 23 in Acinetobacter Baumannii
    Antimicrobial Agents and Chemotherapy, 2007
    Co-Authors: Stephane Corvec, Laurent Poirel, Thierry Naas, Henri Drugeon, Patrice Nordmann
    Abstract:

    The genetic structures surrounding the plasmid-carried blaOXA-23 oxacillinase gene, encoding resistance to carbapenems, were studied in Acinetobacter Baumannii. ISAba1 and the novel element ISAba4 were detected upstream of the blaOXA-23 gene, providing promoter sequences for its expression. These insertion elements were likely involved in transposition processes at the origin of acquisition of this β-lactamase gene.

Robert A Bonomo - One of the best experts on this subject based on the ideXlab platform.

  • case report successful rescue therapy of extensively drug resistant Acinetobacter Baumannii osteomyelitis with cefiderocol
    Open Forum Infectious Diseases, 2020
    Co-Authors: Michael M Dagher, Robert A Bonomo, Felicia Ruffin, Steven H Marshall, Magdalena Taracila, Rachel M Reilly, Vance G Fowler, Joshua T Thaden
    Abstract:

    Cefiderocol is a novel catechol siderophore cephalosporin antibiotic developed to treat resistant gram-negative infections. We describe its successful use as rescue therapy, combined with surgical debridement, to treat a patient with osteomyelitis due to extensively drug-resistant Acinetobacter Baumannii. Bacterial whole-genome sequencing identified the strain and antibiotic resistance determinants.

  • new treatment options against carbapenem resistant Acinetobacter Baumannii infections
    Antimicrobial Agents and Chemotherapy, 2019
    Co-Authors: Burcu Isler, Robert A Bonomo, Yohei Doi, David L Paterson
    Abstract:

    Carbapenem-resistant Acinetobacter Baumannii (CRAB) is a perilous nosocomial pathogen causing substantial morbidity and mortality. Current treatment options for CRAB are limited and suffer from pharmacokinetic limitations, such as high toxicity and low plasma levels. As a result, CRAB is declared as the top priority pathogen by the World Health Organization for the investment in new drugs. This urgent need for new therapies, in combination with faster FDA approval process, accelerated new drug development and placed several drug candidates in the pipeline. This article reviews available information about the new drugs and other therapeutic options focusing on agents in clinical or late-stage preclinical studies for the treatment of CRAB, and it evaluates their expected benefits and potential shortcomings.

  • transcriptome remodeling of Acinetobacter Baumannii during infection and treatment
    Mbio, 2017
    Co-Authors: Meredith S Wright, Robert A Bonomo, Michael R Jacobs, Mark Raymond Adams
    Abstract:

    Acinetobacter Baumannii is an increasingly common multidrug-resistant pathogen in health care settings. Although the genetic basis of antibiotic resistance mechanisms has been extensively studied, much less is known about how genetic variation contributes to other aspects of successful infections. Genetic changes that occur during host infection and treatment have the potential to remodel gene expression patterns related to resistance and pathogenesis. Longitudinal sets of multidrug-resistant A. Baumannii isolates from eight patients were analyzed by RNA sequencing (RNA-seq) to identify differentially expressed genes and link them to genetic changes contributing to transcriptional variation at both within-patient and population levels. The number of differentially expressed genes among isolates from the same patient ranged from 26 (patient 588) to 145 (patient 475). Multiple patients had isolates with differential gene expression patterns related to mutations in the pmrAB and adeRS two-component regulatory system genes, as well as significant differences in genes related to antibiotic resistance, iron acquisition, amino acid metabolism, and surface-associated proteins. Population level analysis revealed 39 genetic regions with clade-specific differentially expressed genes, for which 19, 8, and 3 of these could be explained by insertion sequence mobilization, recombination-driven sequence variation, and intergenic mutations, respectively. Multiple types of mutations that arise during infection can significantly remodel the expression of genes that are known to be important in pathogenesis.IMPORTANCE Health care-associated multidrug-resistant Acinetobacter Baumannii can cause persistent infections in patients, but bacterial cells must overcome host defenses and antibiotic therapies to do so. Genetic variation arises during host infection, and new mutations are often enriched in genes encoding transcriptional regulators, iron acquisition systems, and surface-associated structures. In this study, genetic variation was shown to result in transcriptome remodeling at the level of individual patients and across phylogenetic groups. Differentially expressed genes include those related to capsule modification, iron acquisition, type I pili, and antibiotic resistance. Population level transcriptional variation reflects genome dynamics over longer evolutionary time periods, and convergent transcriptional changes support the adaptive significance of these regions. Transcriptional changes can be attributed to multiple types of genomic change, but insertion sequence mobilization had a predominant effect. The transcriptional effects of mutations that arise during infection highlight the rapid adaptation of A. Baumannii during host exposure.

  • genome dynamics of multidrug resistant Acinetobacter Baumannii during infection and treatment
    Genome Medicine, 2016
    Co-Authors: Meredith S Wright, Robert A Bonomo, Alina Iovleva, Michael R Jacobs, Mark Raymond Adams
    Abstract:

    Background Limited treatment options are available for patients infected with multidrug (MDR)- or pan-drug (PDR)-resistant bacterial pathogens, resulting in infections that can persist for weeks or months. In order to better understand transmission and evolutionary dynamics of MDR Acinetobacter Baumannii (Ab) during long-term infection, we analyzed genomes from a series of isolates from individual patients at isolate-specific, patient-specific, and population levels.

  • Acinetobacter Baumannii rompa vaccine dose alters immune polarization and immunodominant epitopes
    Vaccine, 2013
    Co-Authors: Lin Lin, Brandon Tan, Paul Pantapalangkoor, Andrea M Hujer, Magdalena A Taracila, Robert A Bonomo, Brad Spellberg
    Abstract:

    Background The rOmpA vaccine has been shown to protect mice from lethal infection caused by extreme-drug-resistant (XDR) Acinetobacter Baumannii. The role of dose in immunology of the rOmpA vaccine was explored.

Thierry Naas - One of the best experts on this subject based on the ideXlab platform.

Jordi Vila - One of the best experts on this subject based on the ideXlab platform.

  • effect of biofilm formation on the survival of Acinetobacter Baumannii on dry surfaces
    Journal of Hospital Infection, 2012
    Co-Authors: Paula Espinal, Sara Marti, Jordi Vila
    Abstract:

    Summary Background Acinetobacter Baumannii is emerging as an important hospital pathogen, which can persist in the environment for extended periods of time. It is known to produce biofilms, a community of bacteria enclosed within a protective polymeric matrix. Aim To establish whether the effect of biofilm formation by Acinetobacter Baumannii may be associated with persistence in the hospital environment. Methods The effect of biofilm formation on the survival of A. Baumannii on dry surfaces was investigated in biofilm-forming compared to non-biofilm-forming strains. Survival assays were determined by viable counts of the cells inoculated on to glass cover slips and stored under controlled conditions of temperature and relative humidity. Findings The survival times for the biofilm-forming strains were longer than for the non-biofilm-forming ones (36 vs 15 days, respectively, P Conclusion Biofilm formation increases the survival rate of A. Baumannii on dry surfaces and may contribute to its persistence in the hospital environment, increasing the probability of causing nosocomial infections and outbreaks.

  • effect of biofilm formation on the survival of Acinetobacter Baumannii on dry surfaces
    Journal of Hospital Infection, 2012
    Co-Authors: Paula Espinal, Sara Marti, Jordi Vila
    Abstract:

    BACKGROUND: Acinetobacter Baumannii is emerging as an important hospital pathogen, which can persist in the environment for extended periods of time. It is known to produce biofilms, a community of bacteria enclosed within a protective polymeric matrix. AIM: To establish whether the effect of biofilm formation by Acinetobacter Baumannii may be associated with persistence in the hospital environment. METHODS: The effect of biofilm formation on the survival of A. Baumannii on dry surfaces was investigated in biofilm-forming compared to non-biofilm-forming strains. Survival assays were determined by viable counts of the cells inoculated on to glass cover slips and stored under controlled conditions of temperature and relative humidity. FINDINGS: The survival times for the biofilm-forming strains were longer than for the non-biofilm-forming ones (36 vs 15 days, respectively, P<0.001). Scanning and transmission electron microscopy studies showed a polysaccharide layer and appendages in the biofilm-forming strains, not in the non-biofilm forming ones. CONCLUSION: Biofilm formation increases the survival rate of A. Baumannii on dry surfaces and may contribute to its persistence in the hospital environment, increasing the probability of causing nosocomial infections and outbreaks.

  • growth of Acinetobacter Baumannii in pellicle enhanced the expression of potential virulence factors
    PLOS ONE, 2011
    Co-Authors: Sara Marti, Jordi Vila, Yassine Nait Chabane, Stephane Alexandre, Laurent Coquet, Thierry Jouenne
    Abstract:

    Background Interestingly, Acinetobacter Baumannii presents an enhanced capacity to form biofilms (also named pellicles) at the air-liquid interface as compared to the other Acinetobacter species. This characteristic questions the contribution of this phenotype to an increased risk of clinical infections by this pathogen.

  • craa a major facilitator superfamily efflux pump associated with chloramphenicol resistance in Acinetobacter Baumannii
    Antimicrobial Agents and Chemotherapy, 2009
    Co-Authors: Sara Marti, Paula Espinal, Paula Martinez, Isidre Gibert, Ignasi Roca, Jordi Vila
    Abstract:

    Acinetobacter Baumannii has been increasingly associated with hospital-acquired infections, and the presence of multidrug resistance strains is of great concern to clinicians. A. Baumannii is thought to possess a great deal of intrinsic resistance to several antimicrobial agents, including chloramphenicol, although the mechanisms involved in such resistance are not well understood. In this work, we have identified a major facilitator superfamily efflux pump present in most A. Baumannii strains, displaying strong substrate specificity toward chloramphenicol.

  • in vitro activity of ceftobiprole against Acinetobacter Baumannii clinical isolates
    International Journal of Antimicrobial Agents, 2009
    Co-Authors: Sara Marti, Paula Espinal, Javier Sanchezcespedes, Jordi Vila
    Abstract:

    Acinetobacter Baumannii is a multiresistant opportunistic nosocomial pathogen responsible for outbreaks worldwide. The main infection caused by this microorganism is nosocomial pneumonia, in particular ventilator-associated pneumonia in patients in Intensive Care Units. Treatment of these nosocomial infections is becoming problematic because the level of resistance to antimicrobial agents is rising. Ceftobiprole is a new cephalosporin with activity against Gram-positive and Gram-negative pathogens. This study evaluated the in vitro activity of ceftobiprole against a collection of 58 A. Baumannii clinical isolates and showed that the activity of ceftobiprole was superior to ceftazidime and cefepime when the bla(ADC)-like gene was not expressed or was expressed at a low level.

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