scholarly journals Acquisition of a Plasmid-Borne blaOXA-58 Gene with an Upstream IS1008 Insertion Conferring a High Level of Carbapenem Resistance to Acinetobacter baumannii

2008 ◽  
Vol 52 (7) ◽  
pp. 2573-2580 ◽  
Author(s):  
Te-Li Chen ◽  
Roy Chen-Chih Wu ◽  
Men-Fang Shaio ◽  
Chang-Phone Fung ◽  
Wen-Long Cho
Keyword(s):  
Acinetobacter Baumannii ◽  
Clinical Isolate ◽  
Shuttle Vector ◽  
Carbapenem Resistance ◽  
Open Reading Frames ◽  
Transcription Control ◽  
Genetic Construct ◽  
Fold Reduction ◽  
High Level ◽  
Reading Frames

ABSTRACT The oxacillinase gene was reported to confer limited resistance to carbapenem in Acinetobacter baumannii. In this study, we have demonstrated that an A. baumannii clinical isolate harboring a plasmid, pTVICU53, has 11,037 bp encoding 13 open reading frames. A bla OXA-58 gene with an upstream insertion of truncated ISAba3 (ΔISAba3) and IS1008 was found in this plasmid. ΔISAba3and IS1008 provided two independent promoters for the transcription control of the bla OXA-58 gene. The transformation of pTVICU53 or a shuttle vector bearing IS1008-ΔISAba3-bla OXA-58 to different A. baumannii recipients can increase their MICs of carbapenem 64- to 256-fold. The deletion of promoters provided by IS1008 resulted in dramatic decreases in bla OXA-58 transcription and a 32- to 64-fold reduction in the carbapenem MIC. These findings highlight that A. baumannii might develop carbapenem resistance with a single transformation step, taking up a plasmid containing a genetic construct with a potentially high level of transcription of the bla OXA-58 gene.

scholarly journals A Plasmid-Borne blaOXA-58 Gene Confers Imipenem Resistance to Acinetobacter baumannii Isolates from a Lebanese Hospital

2008 ◽  
Vol 52 (11) ◽  
pp. 4115-4120 ◽  
Author(s):  
Raffaele Zarrilli ◽  
Domenico Vitale ◽  
Anna Di Popolo ◽  
Maria Bagattini ◽  
Ziad Daoud ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Insertion Sequence ◽  
Carbapenem Resistance ◽  
Multidrug Resistant ◽  
Open Reading Frames ◽  
Mosaic Structure ◽  
University Hospital ◽  
Origins Of Replication ◽  
Imipenem Resistance ◽  
Reading Frames

ABSTRACT We investigated the basis of the carbapenem resistance of 17 multidrug-resistant Acinetobacter baumannii clinical isolates collected from 2004 to 2005 at the Saint George University Hospital in Beirut, Lebanon. A. baumannii isolates were clonally related and were susceptible to colistin and trimethoprim-sulfamethoxazole, susceptible or intermediate to ampicillin-sulbactam and meropenem, and resistant to all other antimicrobials. Conjugation experiments demonstrated that resistance to imipenem could be transferred along with a plasmid containing the carbapenem-hydrolyzing oxacillinase bla OXA-58 gene. The plasmid that we called pABIR was 29,823 bp in size and showed a novel mosaic structure composed of two origins of replication, four insertion sequence (IS) elements, and 28 open reading frames. The bla OXA-58 gene was flanked by IS18 and ISAba3 elements at the 5′ and 3′ ends, respectively. The production of the carbapenem-hydrolyzing oxacillinase OXA-58 was apparently the only mechanism for carbapenem resistance in A. baumannii isolates causing the outbreak at the Lebanese Hospital.

scholarly journals Heterochromatic Stellate Gene Cluster in Drosophila melanogaster: Structure and Molecular Evolution

Genetics ◽  
1997 ◽  
Vol 146 (1) ◽  
pp. 253-262 ◽  
Author(s):  
Alexei V Tulin ◽  
Galina L Kogan ◽  
Dominik Filipp ◽  
Maria D Balakireva ◽  
Vladimir A Gvozdev
Keyword(s):  
Drosophila Melanogaster ◽  
Molecular Evolution ◽  
Protein Kinase Ck2 ◽  
Unknown Origin ◽  
Open Reading Frames ◽  
Β Subunit ◽  
Retrotransposon Insertion ◽  
High Level ◽  
Kinase Ck2 ◽  
Reading Frames

The 30-kb cluster comprising close to 20 copies of tandemly repeated Stellate genes was localized in the distal heterochromatin of the X chromosome. Of 10 sequenced genes, nine contain undamaged open reading frames with extensive similarity to protein kinase CK2 β-subunit; one gene is interrupted by an insertion. The heterochromatic array of Stellate repeats is divided into three regions by a 4.5-kb DNA segment of unknown origin and a retrotransposon insertion: the A region (∼14 Stellate genes), the adjacent B region (approximately three Stellate genes), and the C region (about four Stellate genes). The sequencing of Stellate copies located along the discontinuous cluster revealed a complex pattern of diversification. The lowest level of divergence was detected in nearby Stellate repeats. The marginal copies of the A region, truncated or interrupted by an insertion, escaped homogenization and demonstrated high levels of divergence. Comparison of copies in the B and C regions, which are separated by a retrotransposon insertion, revealed a high level of diversification. These observations suggest that homogenization takes place in the Stellate cluster, but that inserted sequences may impede this process.

scholarly journals High-Level Carbapenem Resistance in OXA-232-Producing Raoultella ornithinolytica Triggered by Ertapenem Therapy

2019 ◽  
Vol 64 (1) ◽  
Author(s):  
Alina Iovleva ◽  
Roberta T. Mettus ◽  
Christi L. McElheny ◽  
Marissa P. Griffith ◽  
Mustapha M. Mustapha ◽  
...  
Keyword(s):  
Rapid Development ◽  
Carbapenem Resistance ◽  
Resistant Isolate ◽  
Clinical Microbiology Laboratory ◽  
Loss Of Function ◽  
Content Type ◽  
Carbapenem Resistant ◽  
Class D ◽  
Fold Reduction ◽  
High Level

ABSTRACT OXA-232 is an OXA-48-group class D β-lactamase that hydrolyzes expanded-spectrum cephalosporins and carbapenems at low levels. Clinical strains producing OXA-232 are sometimes susceptible to carbapenems, making it difficult to identify them in the clinical microbiology laboratory. We describe the development of carbapenem resistance in sequential clinical isolates of Raoultella ornithinolytica carrying blaOXA-232 in a hospitalized patient, where the ertapenem MIC increased from 0.5 μg/ml to 512 μg/ml and the meropenem MIC increased from 0.125 μg/ml to 32 μg/ml during the course of ertapenem therapy. Whole-genome sequencing (WGS) analysis identified loss-of-function mutations in ompC and ompF in carbapenem-resistant isolates that were not present in the initial carbapenem-susceptible isolate. Complementation of a carbapenem-resistant isolate with an intact ompF gene resulted in 16- to 32-fold reductions in carbapenem MICs, whereas complementation with intact ompC resulted in a 2-fold reduction in carbapenem MICs. Additionally, blaOXA-232 expression increased 2.9-fold in a carbapenem-resistant isolate. Rapid development of high-level carbapenem resistance in initially carbapenem-susceptible OXA-232-producing R. ornithinolytica under selective pressure from carbapenem therapy highlights the diagnostic challenges in detecting Enterobacteriaceae strains producing this inefficient carbapenemase.

scholarly journals Multicity Outbreak of Carbapenem-Resistant Acinetobacter baumannii Isolates Producing the Carbapenemase OXA-40

2006 ◽  
Vol 50 (9) ◽  
pp. 2941-2945 ◽  
Author(s):  
Karen Lolans ◽  
Thomas W. Rice ◽  
L. Silvia Munoz-Price ◽  
John P. Quinn
Keyword(s):  
Acinetobacter Baumannii ◽  
Carbapenem Resistance ◽  
The United States ◽  
Nucleotide Sequencing ◽  
Sequencing Analysis ◽  
Carbapenem Resistant ◽  
Extended Care ◽  
Care Facilities ◽  
High Level ◽  
First Time

ABSTRACT During 2005 we detected a multicity outbreak of infections or colonization due to high-level imipenem-resistant Acinetobacter baumannii (MIC, 64 μg/ml). One hundred isolates from diverse sources were obtained from seven acute-care hospitals and two extended-care facilities; 97% of the isolates belonged to one clone. Susceptibility testing of the first 42 isolates (January to April 2005) revealed broad resistance profiles. Half of the isolates were susceptible to ceftazidime, with many isolates susceptible only to colistin. The level of AmpC β-lactamase expression was stronger in isolates resistant to ceftazidime. PCR and subsequent nucleotide sequencing analysis identified bla OXA-40. The presence of an OXA-40 β-lactamase in these isolates correlated with the carbapenem resistance. By Southern blot analysis, a bla OXA-40-specific probe revealed that the gene was both plasmid and chromosomally located. This is the first time in the United States that such carbapenem resistance in A. baumannii has been attributable to a carbapenemase.

scholarly journals Characterization of a Genetic Element Carrying the Macrolide Efflux Gene mef(A) in Streptococcus pneumoniae

2000 ◽  
Vol 44 (9) ◽  
pp. 2585-2587 ◽  
Author(s):  
Maria Santagati ◽  
Francesco Iannelli ◽  
Marco R. Oggioni ◽  
Stefania Stefani ◽  
Gianni Pozzi
Keyword(s):  
Streptococcus Pneumoniae ◽  
Resistance Gene ◽  
Clinical Isolate ◽  
Open Reading Frames ◽  
Genetic Element ◽  
Reading Frames

ABSTRACT The mef(A) gene from a clinical isolate ofStreptococcus pneumoniae exhibiting the M-type resistance to macrolides was found to be part of the 7,244-bp chromosomal element Tn1207.1, which contained 8 open reading frames.orf2 encodes a resolvase/invertase, and orf5 is a homolog of the macrolide-streptogramin B resistance genemsr(SA).

scholarly journals Extended-Spectrum Cephalosporinase in Acinetobacter baumannii

2010 ◽  
Vol 54 (8) ◽  
pp. 3484-3488 ◽  
Author(s):  
José-Manuel Rodríguez-Martínez ◽  
Patrice Nordmann ◽  
Esthel Ronco ◽  
Laurent Poirel
Keyword(s):  
Acinetobacter Baumannii ◽  
Clinical Isolate ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Extended Spectrum ◽  
Class C ◽  
High Level ◽  
Level Resistance

ABSTRACT An AmpC-type β-lactamase conferring high-level resistance to expanded-spectrum cephalosporins and monobactams was characterized from an Acinetobacter baumannii clinical isolate. This class C β-lactamase (named ADC-33) possessed a Pro210Arg substitution together with a duplication of an Ala residue at position 215 (inside the Ω-loop) compared to a reference AmpC cephalosporinase from A. baumannii. ADC-33 hydrolyzed ceftazidime, cefepime, and aztreonam at high levels, which allows the classification of this enzyme as an extended-spectrum AmpC (ESAC). Site-directed mutagenesis confirmed the role of both substitutions in its ESAC property.

scholarly journals Insights into the Resistome and Phylogenomics of a ST195 Multidrug-Resistant Acinetobacter baumannii Clinical Isolate from the Czech Republic

Life ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1079
Author(s):  
Patrik Mlynarcik ◽  
Monika Dolejska ◽  
Iva Vagnerova ◽  
Jana Petrzelova ◽  
Iva Sukkar ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Clinical Isolate ◽  
Efflux Pump ◽  
Resistance Mechanism ◽  
Carbapenem Resistance ◽  
Multidrug Resistant ◽  
Clinical Settings ◽  
Sequencing Analysis ◽  
Pump System ◽  
The Czech Republic

Increasing antimicrobial resistance in nosocomial pathogens, such as Acinetobacter baumannii, is becoming a serious threat to public health. It is necessary to detect β-lactamase-producing microorganisms in clinical settings to be able to control the spread of carbapenem resistance. This study was conducted to evaluate the presence of β-lactamases in a selected clinical isolate of A. baumannii of ST2P/ST195Ox and to characterize possible enzymes, as well as its β-lactam resistome, using PCR and whole-genome sequencing analysis. PCR and sequencing confirmed that the isolate harbored five bla gene alleles, namely, blaADC-73, blaTEM-1, blaOXA-23, blaOXA-58 and blaOXA-66, as well as aminoglycosides, macrolides, sulfonamides and tetracyclines resistance determinants, which were either chromosomally and/or plasmid located. Furthermore, a gene order comparison using MAUVE alignment showed multiple changes compared with the clinical isolate of Malaysian A. baumannii AC30 genome and 76 regions with high homology. This study suggests that resistance to β-lactams in this A. baumannii isolate is mainly due to an overproduction of β-lactamases in combination with other resistance mechanism (efflux pump system).

scholarly journals Differences in editing of mitochondrial nad3 transcripts from CMS and fertile carrots.

2001 ◽  
Vol 48 (3) ◽  
pp. 711-717 ◽  
Author(s):  
M Rurek ◽  
M Szklarczyk ◽  
N Adamczyk ◽  
B Michalik ◽  
H Augustyniak
Keyword(s):  
Amino Acids ◽  
Nucleotide Sequence ◽  
Sequence Conservation ◽  
Open Reading Frames ◽  
Male Sterile ◽  
Nucleotide Substitutions ◽  
Cytoplasmic Male Sterile ◽  
Fertile Line ◽  
High Level ◽  
Reading Frames

A high level of the nucleotide sequence conservation was found for mitochondrial nad3 gene of carrot. Three silent nucleotide substitutions differentiate nad3 open reading frames from cytoplasmic male sterile and male fertile carrots. All these differences are preserved on the RNA level. Partial and silent editing also distinguished both carrots. Three of the C to U conversions were specific to the fertile line. In the two examined carrot lines editing did not affect the mode of alteration of encoded amino acids.

scholarly journals The groESL Chaperone Operon ofLactobacillus johnsonii

1999 ◽  
Vol 65 (7) ◽  
pp. 3033-3041 ◽  
Author(s):  
D. Carey Walker ◽  
Hany S. Girgis ◽  
Todd R. Klaenhammer
Keyword(s):  
Heat Shock ◽  
Transcription Initiation ◽  
Shuttle Vector ◽  
Stress Protein ◽  
Open Reading Frames ◽  
Northern Analysis ◽  
Temperature Sensitive ◽  
Insertion Element ◽  
Translation Start ◽  
Reading Frames

ABSTRACT The Lactobacillus johnsonii VPI 11088groESL operon was localized on the chromosome near the insertion element IS1223. The operon was initially cloned as a series of three overlapping PCR fragments, which were sequenced and used to design primers to amplify the entire operon. The amplified fragment was used as a probe to recover the chromosomal copy of thegroESL operon from a partial library of L. johnsonii VPI 11088 (NCK88) DNA, cloned in the shuttle vector pTRKH2. The 2,253-bp groESL fragment contained three putative open reading frames, two of which encoded the ubiquitous GroES and GroEL chaperone proteins. Analysis of the groESLpromoter region revealed three transcription initiation sites, as well as three sets of inverted repeats (IR) positioned between the transcription and translation start sites. Two of the three IR sets bore significant homology to the CIRCE elements, implicated in negative regulation of the heat shock response in many bacteria. Northern analysis and primer extension revealed that multiple temperature-sensitive promoters preceded the groESLchaperone operon, suggesting that stress protein production in L. johnsonii is strongly regulated. Maximum groESLtranscription activity was observed following a shift to 55°C, and a 15 to 30-min exposure of log-phase cells to this temperature increased the recovery of freeze-thawed L. johnsonii VPI 11088. These results suggest that a brief, preconditioning heat shock can be used to trigger increased chaperone production and provide significant cross-protection from the stresses imposed during the production of frozen culture concentrates.

scholarly journals Synthesis of a Klebsiella pneumoniae O-Antigen Heteropolysaccharide (O12) Requires an ABC 2 Transporter

2003 ◽  
Vol 185 (5) ◽  
pp. 1634-1641 ◽  
Author(s):  
Luis Izquierdo ◽  
Susana Merino ◽  
Miguel Regué ◽  
Florencia Rodriguez ◽  
Juan M. Tomás
Keyword(s):  
Klebsiella Pneumoniae ◽  
Genomic Library ◽  
Gene Clusters ◽  
Open Reading Frames ◽  
Complete Analysis ◽  
E Coli ◽  
O Antigen ◽  
High Level ◽  
K 12 ◽  
Reading Frames

ABSTRACT A recombinant clone encoding enzymes for Klebsiella pneumoniae O12-antigen lipopolysaccharide (LPS) was found when we screened for serum resistance of a cosmid-based genomic library of K. pneumoniae KT776 (O12:K80) introduced into Escherichia coli DH5α. A total of eight open reading frames (ORFs) (wb O12 gene cluster) were necessary to produce K. pneumoniae O12-antigen LPS in E. coli K-12. A complete analysis of the K. pneumoniae wb O12 cluster revealed an interesting coincidence with the wb O4 cluster of Serratia marcescens from ORF5 to ORF8 (or WbbL to WbbA). This prompted us to generate mutants of K. pneumoniae strain KT776 (O12) and to study complementation between the two enterobacterial wb clusters using mutants of S. marcescens N28b (O4) obtained previously. Both wb gene clusters are examples of ABC 2 transporter-dependent pathways for O-antigen heteropolysaccharides. The wzm-wzt genes and the wbbA or wbbB genes were not interchangeable between the two gene clusters despite their high level of similarity. However, introduction of three cognate genes (wzm-wzt-wbbA or wzm-wzt-wbbB) into mutants unable to produce O antigen allowed production of the specific O antigen. The K. pneumoniae O12 WbbL protein performs the same function as WbbL from S. marcescens O4 in either the S. marcescens O4 or E. coli K-12 genetic background.

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