scholarly journals Variants of Tn 6924 , a Novel Tn 7 Family Transposon Carrying the bla NDM Metallo-β-Lactamase and 14 Copies of the aphA6 Amikacin Resistance Genes Found in Acinetobacter baumannii

2022 ◽  
Author(s):  
Riti Mann ◽  
Rayane Rafei ◽  
Cindy Gunawan ◽  
Christopher J. Harmer ◽  
Mohammad Hamidian
Keyword(s):  
Acinetobacter Baumannii ◽  
Resistance Genes ◽  
Resistance Mechanisms ◽  
Sequence Type ◽  
Content Type ◽  
Carbapenem Resistant ◽  
Globally Distributed

To date, efforts to study the resistance mechanisms of carbapenem-resistant Acinetobacter baumannii have been largely focused on the two major globally distributed clones (GC1 and GC2). ST85 is an emerging sequence type, and unlike other clones, it is associated with the carriage of the bla NDM gene.

scholarly journals First Description of Two Sequence Type 2 Acinetobacter baumannii Isolates Carrying OXA-23 Carbapenemase in Pagellus acarne Fished from the Mediterranean Sea near Bejaia, Algeria

2016 ◽  
Vol 60 (4) ◽  
pp. 2513-2515 ◽  
Author(s):  
Soumia Brahmi ◽  
Abdelaziz Touati ◽  
Axelle Cadière ◽  
Nassima Djahmi ◽  
Alix Pantel ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Mediterranean Sea ◽  
Sequence Type ◽  
Content Type ◽  
Carbapenem Resistant ◽  
Selective Agar ◽  
Agar Media ◽  
The Mediterranean ◽  
First Time

ABSTRACTTo determine the occurrence of carbapenem-resistantAcinetobacter baumanniiin fish fished from the Mediterranean Sea near the Bejaia coast (Algeria), we studied 300 gills and gut samples that had been randomly and prospectively collected during 1 year. After screening on selective agar media, using PCR arrays and whole-genome sequencing, we identified for the first time two OXA-23-producingA. baumanniistrains belonging to the widespread sequence type 2 (ST2)/international clone II and harboring aminoglycoside-modifying enzymes [aac(6′)-Ib andaac(3′)-I genes].

scholarly journals Accumulation of Antibiotic Resistance Genes in Carbapenem-Resistant Acinetobacter baumannii Isolates Belonging to Lineage 2, Global Clone 1, from Outbreaks in 2012–2013 at a Tehran Burns Hospital

mSphere ◽  
2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Masoumeh Douraghi ◽  
Johanna J. Kenyon ◽  
Parisa Aris ◽  
Mahla Asadian ◽  
Sedighe Ghourchian ◽  
...  
Keyword(s):  
Middle East ◽  
Acinetobacter Baumannii ◽  
Resistance Genes ◽  
Carbapenem Resistance ◽  
Antibiotic Resistant ◽  
Content Type ◽  
Carbapenem Resistant ◽  
East Region ◽  
Lineage 2 ◽  
Middle East Region

ABSTRACT The worldwide distribution of carbapenem-resistant Acinetobacter baumannii (CRAB) has become a global concern, particularly in countries where antibiotic prescription is not tightly regulated. However, knowledge of the genomic aspects of CRAB from many parts of the world is still limited. Here, 50 carbapenem-resistant A. baumannii isolates recovered at a single hospital in Tehran, Iran, during several outbreaks in 2012 and 2013 were found to be resistant to multiple antibiotics. They were examined using PCR mapping and multilocus sequence typing (MLST). All Iranian strains belonged to sequence type 328 in the Institut Pasteur MLST scheme (ST328IP), a single-locus variant of ST81IP, and all Iranian strains contained two carbapenem resistance genes, oxa23 and oxa24. The oxa23 gene is in the transposon Tn2006 in AbaR4, which interrupts the chromosomal comM gene. Phylogenetic analysis using whole-genome sequence (WGS) data for 9 isolates showed that they belonged to the same clade, designated the ST81/ST328 clade, within lineage 2 of global clone 1 (GC1). However, there were two groups that included either KL13 or KL18 at the K locus (KL) for capsular polysaccharide synthesis and either a tet39 or an aadB resistance gene, respectively. The genetic context of the resistance genes was determined, and the oxa24 (OXA-72 variant) and tet39 (tetracycline resistance) genes were each in a pdif module in different plasmids. The aadB gene cassette (which encodes gentamicin, kanamycin, and tobramycin resistance) was harbored by pRAY*, and the aphA6 gene (which encodes amikacin resistance) and sul2 gene (which encodes sulfamethoxazole resistance) were each harbored by a different plasmid. The sequences obtained here will underpin future studies of GC1 CRAB strains from the Middle East region. IMPORTANCE Carbapenem-resistant Acinetobacter baumannii strains are among the most critical antibiotic-resistant bacteria causing hospital-acquired infections and treatment failures. The global spread of two clones has been responsible for the bulk of the resistance, in particular, carbapenem resistance. However, there is a substantial gap in our knowledge of which clones and which specific lineages within each clone are circulating in many parts of the world, including Africa and the Middle East region. This is the first genomic analysis of carbapenem-resistant A. baumannii strains from Iran. All the isolates, from a single hospital, belonged to lineage 2 of global clone 1 (GC1) but fell into two groups distinguished by genes in the locus for capsule biosynthesis. The analysis suggests a potential origin of multiply antibiotic-resistant lineage 2 in the Middle East region and highlights the ongoing evolution of carbapenem-resistant GC1 A. baumannii strains. It will enhance future studies on the local and global GC1 population structure.

scholarly journals Copper Resistance of the Emerging Pathogen Acinetobacter baumannii

2016 ◽  
Vol 82 (20) ◽  
pp. 6174-6188 ◽  
Author(s):  
Caitlin L. Williams ◽  
Heather M. Neu ◽  
Jeremy J. Gilbreath ◽  
Sarah L. J. Michel ◽  
Daniel V. Zurawski ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Resistance Genes ◽  
Resistance Mechanisms ◽  
Copper Resistance ◽  
Transcriptional Analysis ◽  
Resistant Bacteria ◽  
Emerging Pathogen ◽  
Amino Acid Homology ◽  
Content Type ◽  
High Concentrations

ABSTRACTAcinetobacter baumanniiis an important emerging pathogen that is capable of causing many types of severe infection, especially in immunocompromised hosts. SinceA. baumanniican rapidly acquire antibiotic resistance genes, many infections are on the verge of being untreatable, and novel therapies are desperately needed. To investigate the potential utility of copper-based antibacterial strategies againstAcinetobacterinfections, we characterized copper resistance in a panel of recent clinicalA. baumanniiisolates. Exposure to increasing concentrations of copper in liquid culture and on solid surfaces resulted in dose-dependent and strain-dependent effects; levels of copper resistance varied broadly across isolates, possibly resulting from identified genotypic variation among strains. Examination of the growth-phase-dependent effect of copper onA. baumanniirevealed that resistance to copper increased dramatically in stationary phase. Moreover,A. baumanniibiofilms were more resistant to copper than planktonic cells but were still susceptible to copper toxicity. Exposure of bacteria to subinhibitory concentrations of copper allowed them to better adapt to and grow in high concentrations of copper; this copper tolerance response is likely achieved via increased expression of copper resistance mechanisms. Indeed, genomic analysis revealed numerous putative copper resistance proteins that share amino acid homology to known proteins inEscherichia coliandPseudomonas aeruginosa. Transcriptional analysis revealed significant upregulation of these putative copper resistance genes following brief copper exposure. Future characterization of copper resistance mechanisms may aid in the search for novel antibiotics againstAcinetobacterand other highly antibiotic-resistant pathogens.IMPORTANCEAcinetobacter baumanniicauses many types of severe nosocomial infections; unfortunately, some isolates have acquired resistance to almost every available antibiotic, and treatment options are incredibly limited. Copper is an essential nutrient but becomes toxic at high concentrations. The inherent antimicrobial properties of copper give it potential for use in novel therapeutics against drug-resistant pathogens. We show thatA. baumanniiclinical isolates are sensitive to copperin vitro, both in liquid and on solid metal surfaces. Since bacterial resistance to copper is mediated though mechanisms of efflux and detoxification, we identified genes encoding putative copper-related proteins inA. baumanniiand showed that expression of some of these genes is regulated by the copper concentration. We propose that the antimicrobial effects of copper may be beneficial in the development of future therapeutics that target multidrug-resistant bacteria.

scholarly journals Novel Aminoglycoside Resistance Transposons and Transposon-Derived Circular Forms Detected in Carbapenem-Resistant Acinetobacter baumannii Clinical Isolates

2016 ◽  
Vol 60 (3) ◽  
pp. 1801-1818 ◽  
Author(s):  
Nabil Karah ◽  
Chinmay Kumar Dwibedi ◽  
Karin Sjöström ◽  
Petra Edquist ◽  
Anders Johansson ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Acinetobacter Baumannii ◽  
Resistance Genes ◽  
Point Mutations ◽  
Antibiotic Resistance Genes ◽  
Opportunistic Pathogen ◽  
Clinical Isolates ◽  
Aminoglycoside Resistance ◽  
Content Type ◽  
Carbapenem Resistant

Acinetobacter baumanniihas emerged as an important opportunistic pathogen equipped with a growing number of antibiotic resistance genes. Our study investigated the molecular epidemiology and antibiotic resistance features of 28 consecutive carbapenem-resistant clinical isolates ofA. baumanniicollected throughout Sweden in 2012 and 2013. The isolates mainly belonged to clonal complexes (CCs) with an extensive international distribution, such as CC2 (n= 16) and CC25 (n= 7). Resistance to carbapenems was related toblaOXA-23(20 isolates),blaOXA-24/40-like(6 isolates),blaOXA-467(1 isolate), and ISAba1-blaOXA-69(1 isolate). Ceftazidime resistance was associated withblaPER-7in the CC25 isolates. Two classical point mutations were responsible for resistance to quinolones in all the isolates. Isolates with high levels of resistance to aminoglycosides carried the 16S rRNA methylasearmAgene. The isolates also carried a variety of genes encoding aminoglycoside-modifying enzymes. Several novel structures involved in aminoglycoside resistance were identified, including Tn6279, ΔTn6279, Ab-ST3-aadB, and different assemblies of Tn6020and TnaphA6. Importantly, a number of circular forms related to the IS26or ISAba125composite transposons were detected. The frequent occurrence of these circular forms in the populations of several isolates indicates a potential role of these circular forms in the dissemination of antibiotic resistance genes.

scholarly journals Prevalence, Risk Factors, and Molecular Epidemiology of Intestinal Carbapenem-Resistant Pseudomonas aeruginosa

2021 ◽  
Author(s):  
Yanyan Hu ◽  
Yan Qing ◽  
Jiawei Chen ◽  
Congcong Liu ◽  
Jiayue Lu ◽  
...  
Keyword(s):  
Risk Factors ◽  
Pseudomonas Aeruginosa ◽  
Gastrointestinal Tract ◽  
Resistance Genes ◽  
Acquired Resistance ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Human Gastrointestinal Tract ◽  
Content Type ◽  
Carbapenem Resistant

Pseudomonas aeruginosa may become multidrug-resistant (MDR) due to multiple inherited and acquired resistance mechanisms. The human gastrointestinal tract is known as a reservoir of P. aeruginosa and its resistance genes.

scholarly journals Molecular Epidemiology of Emerging bla OXA-23-Like - and bla OXA-24-Like -Carrying Acinetobacter baumannii in Taiwan

2018 ◽  
Vol 62 (3) ◽  
Author(s):  
Shu-Chen Kuo ◽  
Wei-Cheng Huang ◽  
Tzu-Wen Huang ◽  
Hui-Ying Wang ◽  
Jui-Fen Lai ◽  
...  
Keyword(s):  
Molecular Epidemiology ◽  
Acinetobacter Baumannii ◽  
Resistance Genes ◽  
Aminoglycoside Resistance ◽  
S1 Nuclease ◽  
Content Type ◽  
Class A ◽  
Carbapenem Resistant ◽  
Aminoglycoside Resistance Genes ◽  
Resistance Island

ABSTRACT The rate of recovery of carbapenem-resistant Acinetobacter baumannii (CRAB) isolates has increased significantly in recent decades in Taiwan. This study investigated the molecular epidemiology of CRAB with a focus on the mechanisms of resistance and spread in isolates with bla OXA-23-like or bla OXA-24-like . All 555 CRAB isolates in our multicenter collection, which were recovered from 2002 to 2010, were tested for the presence of class A, B, and D carbapenemase genes. All isolates with bla OXA-23-like or bla OXA-24-like were subjected to pulsed-field gel electrophoresis, and 82 isolates (60 isolates with bla OXA-23-like and 22 isolates with bla OXA-24-like ) were selected for multilocus sequence typing to determine the sequence type (ST) and clonal group (CG) and for detection of additional β-lactamase and aminoglycoside resistance genes. The flanking regions of carbapenem and aminoglycoside resistance genes were identified by PCR mapping and sequencing. The localization of bla OXA was determined by S1 nuclease and I-CeuI assays. The numbers of CRAB isolates carrying bla OXA-23-like or bla OXA-24-like , especially those carrying bla OXA-23-like , increased significantly from 2008 onward. The bla OXA-23-like gene was carried by antibiotic resistance genomic island 1 (AbGRI1)-type structures located on plasmids and/or the chromosome in isolates of different STs (CG92 and novel CG786), whereas bla OXA-24-like was carried on plasmids in CRAB isolates of limited STs (CG92). No class A or B carbapenemase genes were identified. Multiple aminoglycoside resistance genes coexisted in CRAB. Tn 6180 -borne armA was found in 74 (90.2%) CRAB isolates, and 58 (70.7%) isolates had Tn 6179 upstream, constituting AbGRI3. bla TEM was present in 38 (46.3%) of the CRAB isolates tested, with 35 (92.1%) isolates containing bla TEM in AbGRI2-type structures, and 61% of ampC genes had IS Aba1 upstream. We conclude that the dissemination and spread of a few dominant lineages of CRAB containing various resistance island structures occurred in Taiwan.

scholarly journals First Report of an OXA-23 Carbapenemase-Producing Acinetobacter baumannii Clinical Isolate Related to Tn2006in Spain

2012 ◽  
Vol 57 (1) ◽  
pp. 589-591 ◽  
Author(s):  
P. Espinal ◽  
M. D. Macià ◽  
I. Roca ◽  
E. Gato ◽  
E. Ruíz ◽  
...  
Keyword(s):  
Genetic Analysis ◽  
Acinetobacter Baumannii ◽  
Clinical Isolate ◽  
Sequence Type ◽  
Content Type ◽  
First Report ◽  
Carbapenem Resistant

ABSTRACTA carbapenem-resistantAcinetobacter baumanniiclinical isolate belonging to European clone II and sequence type 2 was recovered from a patient in the Son Espases hospital in Mallorca, Spain. Genetic analysis showed the presence of theblaOXA-23gene in association with the widely disseminated transposon Tn2006. This is the first reported identification ofA. baumanniicarryingblaOXA-23in Spain.

scholarly journals Evaluation of Clonality and Carbapenem Resistance Mechanisms among Acinetobacter baumannii-Acinetobacter calcoaceticus Complex and Enterobacteriaceae Isolates Collected in European and Mediterranean Countries and Detection of Two Novel β-Lactamases, GES-22 and VIM-35

2014 ◽  
Vol 58 (12) ◽  
pp. 7358-7366 ◽  
Author(s):  
Mariana Castanheira ◽  
Sarah E. Costello ◽  
Leah N. Woosley ◽  
Lalitagauri M. Deshpande ◽  
Todd A. Davies ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Carbapenem Resistance ◽  
Acinetobacter Calcoaceticus ◽  
Resistance Mechanisms ◽  
The Novel ◽  
Intrinsic Resistance ◽  
Content Type ◽  
Carbapenem Resistant ◽  
Mediterranean Countries ◽  
Class 1

ABSTRACTWe evaluated doripenem-resistantAcinetobacter baumannii-Acinetobacter calcoaceticuscomplex (ACB;n= 411) andEnterobacteriaceae(n= 92) isolates collected from patients from 14 European and Mediterranean countries during 2009 to 2011 for the presence of carbapenemase-encoding genes and clonality. Following susceptibility testing, carbapenem-resistant (doripenem MIC, >2 μg/ml) isolates were screened for carbapenemases. New β-lactamase genes were expressed in a common background and susceptibility was tested. Class 1 integrons were sequenced. Clonality was evaluated by pulsed-field gel electrophoresis and multilocus sequence typing (Pasteur scheme). Relative expression of β-lactam intrinsic resistance mechanisms was determined for carbapenemase-negativeEnterobacteriaceae. ACB andEnterobacteriaceaedisplayed 58.9 and 0.9% doripenem resistance, respectively.blaOXA-23,blaOXA-58, andblaOXA-24/OXA-40were detected among 277, 77, and 29 ACB, respectively (in 8, 6, and 5 countries). Ten Turkish isolates carriedblaGES-11orblaGES-22. GES-22 (G243A and M169L mutations in GES-1) had an extended-spectrum β-lactamase profile. A total of 33 clusters of ≥2 ACB isolates were observed, and 227 isolates belonged to sequence type 2/international clone II. Other international clones were limited to Turkey and Israel. Doripenem-resistantEnterobacteriaceaeincreased significantly (0.7 to 1.6%), and 15blaKPC-2- and 22blaKPC-3-carrying isolates, mostly belonging to clonal complexes 11 and 258, were observed.Enterobacteriaceaeisolates producing OXA-48 (n= 16; in Turkey and Italy), VIM-1 (n= 10; in Greece, Poland, and Spain), VIM-26 (n= 1; in Greece), and IMP-19, VIM-4, and the novel VIM-35 (n= 1 each from Poland) were detected. VIM-35 had one substitution compared to VIM-1 (A235T) and a similar susceptibility profile. One or more resistance mechanisms were identified in 4/6 carbapenemase-negativeEnterobacteriaceae. This broad evaluation confirms results from country-specific surveys and shows a highly diverse population of carbapenemase-producing ACB andEnterobacteriaceaein Europe and Mediterranean countries.

scholarly journals A Nationwide Screen of Carbapenem-Resistant Klebsiella pneumoniae Reveals an Isolate with Enhanced Virulence and Clinically Undetected Colistin Heteroresistance

2019 ◽  
Vol 63 (5) ◽  
Author(s):  
Jessie E. Wozniak ◽  
Victor I. Band ◽  
Andrew B. Conley ◽  
Lavanya Rishishwar ◽  
Eileen M. Burd ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Klebsiella Pneumoniae ◽  
Resistance Genes ◽  
Resistance Mechanisms ◽  
Gene Encoding ◽  
Content Type ◽  
Carbapenem Resistant

ABSTRACT The convergence of hypervirulence and multidrug resistance in Klebsiella pneumoniae is a significant concern. Here, we report the first screen for hypermucoviscosity, a trait associated with increased virulence, using a U.S. surveillance collection of carbapenem-resistant (CR) K. pneumoniae isolates. We identified one hypermucoviscous isolate, which carried a gene encoding the KPC-3 carbapenemase, among numerous resistance genes. The strain further exhibited colistin heteroresistance undetected by diagnostics. This convergence of diverse resistance mechanisms and increased virulence underscores the need for enhanced K. pneumoniae surveillance.

scholarly journals Evolution of Carbapenem-Resistant Acinetobacter baumannii Revealed through Whole-Genome Sequencing and Comparative Genomic Analysis

2014 ◽  
Vol 59 (2) ◽  
pp. 1168-1176 ◽  
Author(s):  
Henan Li ◽  
Fei Liu ◽  
Yawei Zhang ◽  
Xiaojuan Wang ◽  
Chunjiang Zhao ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Acinetobacter Baumannii ◽  
Genome Sequencing ◽  
Resistance Genes ◽  
Genomic Analysis ◽  
Comparative Genomic Analysis ◽  
Comparative Genomic ◽  
Whole Genome ◽  
Content Type ◽  
Carbapenem Resistant

ABSTRACTAcinetobacter baumanniiis a globally important nosocomial pathogen characterized by an evolving multidrug resistance. A total of 35 representative clinicalA. baumanniistrains isolated from 13 hospitals in nine cities in China from 1999 to 2011, including 32 carbapenem-resistant and 3 carbapenem-susceptibleA. baumanniistrains, were selected for whole-genome sequencing and comparative genomic analysis. Phylogenetic analysis revealed that the earliest strain, strain 1999BJAB11, and two strains isolated in Zhejiang Province in 2004 were the founder strains of carbapenem-resistantA. baumannii. Ten types of AbaR resistance islands were identified, and a previously unreported AbaR island, which comprised a two-component response regulator, resistance-related proteins, and RND efflux system proteins, was identified in two strains isolated in Zhejiang in 2004. Multiple transposons or insertion sequences (ISs) existed in each strain, and these gradually tended to diversify with evolution. Some of these IS elements or transposons were the first to be reported, and most of them were mainly found in strains from two provinces. Genome feature analysis illustrated diversified resistance genes, surface polysaccharides, and a restriction-modification system, even in strains that were phylogenetically and epidemiologically very closely related. IS-mediated deletions were identified in the type VI secretion system region, thecsuEregion, and core lipooligosaccharide (LOS) loci. Recombination occurred in the heme utilization region, and intrinsic resistance genes (blaADCandblaOXA-51-likevariants) and three novelblaOXA-51-likevariants (blaOXA-424,blaOXA-425, andblaOXA-426) were identified. Our results could improve the understanding of the evolutionary processes that contribute to the emergence of carbapenem-resistantA. baumanniistrains and help elucidate the molecular evolutionary mechanism inA. baumannii.

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