scholarly journals Survey on Genetic Diversity, Biofilm Formation, and Detection of Colistin Resistance Genes in Clinical Isolates of Acinetobacter baumannii

2020 ◽  
Vol Volume 13 ◽  
pp. 1547-1558
Author(s):  
Saeed Khoshnood ◽  
Mohammad Savari ◽  
Effat Abbasi Montazeri ◽  
Ahmad Farajzadeh Sheikh
Keyword(s):  
Genetic Diversity ◽  
Acinetobacter Baumannii ◽  
Resistance Genes ◽  
Biofilm Formation ◽  
Clinical Isolates ◽  
Colistin Resistance

scholarly journals A Prospective Study of Acinetobacter baumannii Complex Isolates and Colistin Susceptibility Monitoring by Mass Spectrometry of Microbial Membrane Glycolipids

2018 ◽  
Vol 57 (3) ◽  
Author(s):  
Lisa M. Leung ◽  
Christi L. McElheny ◽  
Francesca M. Gardner ◽  
Courtney E. Chandler ◽  
Sarah L. Bowler ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Acinetobacter Baumannii ◽  
Lipid A ◽  
Membrane Lipids ◽  
Clinical Isolates ◽  
Colistin Resistance ◽  
Hospital System ◽  
Content Type ◽  
Acinetobacter Baumannii Complex ◽  
Gram Negative Organisms

ABSTRACT Acinetobacter baumannii is a prevalent nosocomial pathogen with a high incidence of multidrug resistance. Treatment of infections due to this organism with colistin, a last-resort antibiotic of the polymyxin class, can result in the emergence of colistin-resistant strains. Colistin resistance primarily occurs via modifications of the terminal phosphate moieties of lipopolysaccharide-derived lipid A, which reduces overall membrane electronegativity. These modifications are readily identified by mass spectrometry (MS). In this study, we prospectively collected Acinetobacter baumannii complex clinical isolates from a hospital system in Pennsylvania over a 3-year period. All isolates were evaluated for colistin resistance using standard MIC testing by both agar dilution and broth microdilution, as well as genospecies identification and lipid A profiling using MS analyses. Overall, an excellent correlation between colistin susceptibility and resistance, determined by MIC testing, and the presence of a lipid A modification, determined by MS, was observed with a sensitivity of 92.9% and a specificity of 94.0%. Additionally, glycolipid profiling was able to differentiate A. baumannii complex organisms based on their membrane lipids. With the growth of MS use in clinical laboratories, a reliable MS-based glycolipid phenotyping method that identifies colistin resistance in A. baumannii complex clinical isolates, as well as other Gram-negative organisms, represents an alternative or complementary approach to existing diagnostics.

scholarly journals Growth Retardation, Reduced Invasiveness, and Impaired Colistin-Mediated Cell Death Associated with Colistin Resistance Development in Acinetobacter baumannii

2013 ◽  
Vol 58 (2) ◽  
pp. 828-832 ◽  
Author(s):  
Spyros Pournaras ◽  
Aggeliki Poulou ◽  
Konstantina Dafopoulou ◽  
Yassine Nait Chabane ◽  
Ioulia Kristo ◽  
...  
Keyword(s):  
Cell Death ◽  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Bloodstream Infections ◽  
Single Amino Acid ◽  
Colistin Resistance ◽  
Resistance Development ◽  
Content Type ◽  
Alkyl Hydroperoxide ◽  
Severe Soft Tissue

ABSTRACTTwo colistin-susceptible/colistin-resistant (Cols/Colr) pairs ofAcinetobacter baumanniistrains assigned to international clone 2, which is prevalent worldwide, were sequentially recovered from two patients after prolonged colistin administration. Compared with the respective Colsisolates (Ab248 and Ab299, both having a colistin MIC of 0.5 μg/ml), both Colrisolates (Ab249 and Ab347, with colistin MICs of 128 and 32 μg/ml, respectively) significantly overexpressedpmrCABgenes, had single-amino-acid shifts in the PmrB protein, and exhibited significantly slower growth. The Colrisolate Ab347, tested by proteomic analysis in comparison with its Colscounterpart Ab299, underexpressed the proteins CsuA/B and C from thecsuoperon (which is necessary for biofilm formation). This isolate also underexpressed aconitase B and different enzymes involved in the oxidative stress response (KatE catalase, superoxide dismutase, and alkyl hydroperoxide reductase), suggesting a reduced response to reactive oxygen species (ROS) and, consequently, impaired colistin-mediated cell death through hydroxyl radical production. Colsisolates that were indistinguishable by macrorestriction analysis from Ab299 caused six sequential bloodstream infections, and isolates indistinguishable from Ab248 caused severe soft tissue infection, while Colrisolates indistinguishable from Ab347 and Ab249 were mainly colonizers. In particular, a Colsisolate identical to Ab299 was still invading the bloodstream 90 days after the colonization of this patient by Colrisolates. These observations indicate considerably lower invasiveness ofA. baumanniiclinical isolates following the development of colistin resistance.

scholarly journals Correlation of biofilm formation and antibiotic resistance among clinical and soil isolates of Acinetobacter baumannii in Iraq

2019 ◽  
pp. 1-10 ◽  
Author(s):  
Pakhshan A. Hassan ◽  
Adel K. Khider
Keyword(s):  
Acinetobacter Baumannii ◽  
Congo Red ◽  
Biofilm Formation ◽  
Opportunistic Pathogen ◽  
Microtiter Plate ◽  
Test Tube ◽  
Clinical Isolates ◽  
Diffusion Method ◽  
Biochemical Tests ◽  
Disk Diffusion Method

Acinetobacter baumannii is an opportunistic pathogen that is reported as a major cause of nosocomial infections. The aim of this study was to investigate the biofilm formation by A. baumannii clinical and soil isolates, to display their susceptibility to 11 antibiotics and to study a possible relationship between formation of biofilm and multidrug resistance. During 8 months period, from June 2016 to January 2017, a total of 52 clinical and 22 soil isolates of A. baumannii were collected and identified through conventional phenotypic, chromo agar, biochemical tests, API 20E system, and confirmed genotypically by PCR for blaOXA-51-like gene. Antibiotic susceptibility of isolates was determined by standard disk diffusion method according to Clinical and Laboratory Standard Institute. The biofilm formation was studied using Congo red agar, test tube, and microtiter plate methods. The clinical isolates were 100% resistance to ciprofloxacin, ceftazidime, piperacillin, 96.15% to gentamicin, 96.15% to imipenem, 92.31% to meropenem, and 78.85% to amikacin. The soil A. baumannii isolates were 100% sensitive to imipenem, meropenem, and gentamicin, and 90.1% to ciprofloxacin. All A. baumannii isolates (clinical and soil) were susceptible to polymyxin B. The percentage of biofilm formation in Congo red agar, test tube, and microtiter plate assays was 10.81%, 63.51%, and 86.48%, respectively. More robust biofilm former population was mainly among non-MDR isolates. Isolates with a higher level of resistance tended to form weaker biofilms. The soil isolates exhibited less resistance to antibiotics than clinical isolates. However, the soil isolates produce stronger biofilms than clinical isolates.

Molecular characterization of lpxACD and pmrA/B two-component regulatory system in the colistin resistance Acinetobacter baumannii clinical isolates

Gene Reports ◽  
2020 ◽  
Vol 21 ◽  
pp. 100952
Author(s):  
Mohammad Reza Kandehkar Ghahraman ◽  
Hossein Hosseini-Nave ◽  
Omid Azizi ◽  
Mohammad Reza Shakibaie ◽  
Hamid Reza Mollaie ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Molecular Characterization ◽  
Regulatory System ◽  
Clinical Isolates ◽  
Colistin Resistance ◽  
Two Component

scholarly journals Biofilm formation in carbapenemase-producing Pseudomonas spp. and Acinetobacter baumannii clinical isolates

2018 ◽  
Vol 73 ◽  
pp. 119-120 ◽  
Author(s):  
R. Papa ◽  
I. Bado ◽  
V. Iribarnegaray ◽  
M.J. Gonzalez ◽  
P. Zunino ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Clinical Isolates ◽  
Pseudomonas Spp

scholarly journals Molecular Characterization of Integrons in Epidemiologically Unrelated Clinical Isolates of Acinetobacter baumannii from Italian Hospitals Reveals a Limited Diversity of Gene Cassette Arrays

2002 ◽  
Vol 46 (11) ◽  
pp. 3665-3668 ◽  
Author(s):  
Francesca Gombac ◽  
Maria Letizia Riccio ◽  
Gian Maria Rossolini ◽  
Cristina Lagatolla ◽  
Enrico Tonin ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Acinetobacter Baumannii ◽  
Molecular Characterization ◽  
Horizontal Transfer ◽  
Gene Cassette ◽  
Clinical Isolates

ABSTRACT Integron carriage by 36 epidemiologically unrelated Acinetobacter baumannii isolates collected over an 11-year period from patients in six different Italian hospitals was investigated. Sixteen type 1 integron-positive isolates (44%) were found, 13 of which carried the same array of cassettes, i.e., aacC1, orfX, orfX′, and aadA1a. As ribotype analysis of the isolates demonstrated a notable genetic diversity, horizontal transfer of the entire integron structure or ancient acquisition was hypothesized.

In vitro effect of subminimal inhibitory concentrations of antibiotics on the biofilm formation ability of Acinetobacter baumannii clinical isolates

2017 ◽  
Vol 30 (1) ◽  
pp. 16-24 ◽  
Author(s):  
Maja Bogdan ◽  
Domagoj Drenjancevic ◽  
Ivana Harsanji Drenjancevic ◽  
Branka Bedenic ◽  
Vlasta Zujic Atalic ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Clinical Isolates ◽  
Vitro Effect

scholarly journals Draft Genome Sequences of Clinical Isolates of Multidrug-Resistant Acinetobacter baumannii

2017 ◽  
Vol 5 (5) ◽  
Author(s):  
Keesha E. Erickson ◽  
Nancy E. Madinger ◽  
Anushree Chatterjee
Keyword(s):  
Acinetobacter Baumannii ◽  
Resistance Genes ◽  
Draft Genome ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Genome Sequences ◽  
Content Type ◽  
University Of Colorado ◽  
The University

ABSTRACT We report here the draft genome sequences of two clinically isolated Acinetobacter baumannii strains. These samples were obtained from patients at the University of Colorado Hospital in 2007 and 2013 and encode an estimated 20 and 13 resistance genes, respectively.

scholarly journals Phenotypic and Genotypic Characteristics of Biofilm Formation in Clinical Isolates of Acinetobacter baumannii

2021 ◽  
Vol Volume 14 ◽  
pp. 2613-2624
Author(s):  
Zhaoyinqian Li ◽  
Zixuan Ding ◽  
Yao Liu ◽  
Xinrui Jin ◽  
Jingling Xie ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Clinical Isolates ◽  
Genotypic Characteristics
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