scholarly journals Genetics and Expression of the Carbapenem-Hydrolyzing Oxacillinase Gene blaOXA-23 in Acinetobacter baumannii

2007 ◽  
Vol 51 (4) ◽  
pp. 1530-1533 ◽  
Author(s):  
Stéphane Corvec ◽  
Laurent Poirel ◽  
Thierry Naas ◽  
Henri Drugeon ◽  
Patrice Nordmann
Keyword(s):  
Acinetobacter Baumannii ◽  
The Novel ◽  
Gene Encoding ◽  
Promoter Sequences ◽  
Insertion Elements ◽  
Genetic Structures ◽  
Lactamase Gene

ABSTRACT The genetic structures surrounding the plasmid-carried bla OXA-23 oxacillinase gene, encoding resistance to carbapenems, were studied in Acinetobacter baumannii. ISAba1 and the novel element ISAba4 were detected upstream of the bla OXA-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.

scholarly journals Insertion Sequence ISEcp1B Is Involved in Expression and Mobilization of a blaCTX-M β-Lactamase Gene

2003 ◽  
Vol 47 (9) ◽  
pp. 2938-2945 ◽  
Author(s):  
Laurent Poirel ◽  
Jean-Winoc Decousser ◽  
Patrice Nordmann
Keyword(s):  
Inverted Repeat ◽  
Bacterial Species ◽  
Single Copy ◽  
Gene Encoding ◽  
Promoter Sequences ◽  
Current Spread ◽  
Dna Fragment ◽  
High Level ◽  
Genetic Structures ◽  
Lactamase Gene

ABSTRACT The genetic structures (ca. 10-kb DNA fragment) surrounding the plasmid-borne extended-spectrum β-lactamase bla CTX-M-19 gene in a Klebsiella pneumoniae clinical isolate were determined. This β-lactamase gene was part of a 4,797-bp transposon inserted inside orf1 of Tn1721. Inside this transposon, bla CTX-M-19 was bracketed upstream and downstream by insertion sequences ISE cp1B and IS903D, respectively, and further downstream by a truncated gene encoding an outer membrane protein for iron transport. The single-copy ISEcp1B element was probably involved alone in the mobilization process that led to a 5-bp duplication at the target site of the transposed fragment. This mobilization event probably involved one inverted repeat of ISE cp1B and a second sequence farther away, resembling its second inverted repeat. Additionally, ISEcp1B provided −35 and −10 promoter sequences, contributing to the high-level expression of the bla CTX-M-19 gene. Southern blot analysis failed to identify a reservoir of ISEcp1-like sequences among a series of gram-negative and gram-positive bacterial species usually found in the skin and intestinal human floras. The ability of ISEcp1-like elements to mobilize and to promote the expression of β-lactamase genes may explain, in part, the current spread of CTX-M-type enzymes worldwide.

scholarly journals Identification of the Novel Narrow-Spectrum β-Lactamase SCO-1 in Acinetobacter spp. from Argentina

2007 ◽  
Vol 51 (6) ◽  
pp. 2179-2184 ◽  
Author(s):  
Laurent Poirel ◽  
Stéphane Corvec ◽  
Melina Rapoport ◽  
Pauline Mugnier ◽  
Alejandro Petroni ◽  
...  
Keyword(s):  
Amino Acid Identity ◽  
The Novel ◽  
Gene Encoding ◽  
Class A ◽  
Narrow Spectrum ◽  
A Value ◽  
Acinetobacter Spp ◽  
Encoding Gene ◽  
High Level ◽  
Lactamase Gene

ABSTRACT By studying the β-lactamase content of several Acinetobacter spp. isolates from Argentina, producing the expanded-spectrum β-lactamases (ESBL) VEB-1a or PER-2, a novel Ambler class A β-lactamase gene was identified. It encoded the narrow-spectrum β-lactamase SCO-1, whose activity was inhibited by clavulanic acid. SCO-1 hydrolyzes penicillins at a high level and cephalosporins and carbapenems at a very low level. β-Lactamase SCO-1 was identified from unrelated VEB-1a-positive or PER-2-positive Acinetobacter spp. isolates recovered from three hospitals. The bla SCO-1 gene was apparently located on a plasmid of ca. 150 kb from all cases but was not associated with any ESBL-encoding gene. The G+C content of the bla SCO gene was 52%, a value that does not correspond to that of the A. baumannii genome (39%). β-Lactamase SCO-1 shares 47% amino acid identity with CARB-5 and ca. 40% with the enzymes TEM, SHV, and CTX-M. A gene encoding a putative resolvase was identified downstream of the bla SCO-1 gene, but its precise way of acquisition remains to be determined.

scholarly journals Association of the Extended-Spectrum β-Lactamase Gene blaTLA-1 with a Novel ISCR Element, ISCR20

2010 ◽  
Vol 54 (9) ◽  
pp. 4026-4028 ◽  
Author(s):  
Beatrice Berçot ◽  
Laurent Poirel ◽  
Jesus Silva-Sanchez ◽  
Patrice Nordmann
Keyword(s):  
Amino Acid ◽  
Mexico City ◽  
Insertion Sequence ◽  
Amino Acid Identity ◽  
Gene Encoding ◽  
Acid Identity ◽  
Promoter Sequences ◽  
Extended Spectrum ◽  
Lactamase Gene

ABSTRACT The bla TLA-1 gene encoding an extended-spectrum β-lactamase was identified in 11 enterobacterial isolates from Mexico City, Mexico. This gene was located on different plasmids and plasmid types with different sizes and incompatibility groups. It was associated with a novel insertion sequence, ISCR20, encoding a putative transposase that shared only 20% amino acid identity with the most closely related transposase of ISCR1. The ISCR20 element provided specific promoter sequences for expression of the bla TLA-1 gene.

scholarly journals Carbapenem-Resistant Acinetobacter baumannii Isolates from Tunisia Producing the OXA-58-Like Carbapenem-Hydrolyzing Oxacillinase OXA-97

2008 ◽  
Vol 52 (5) ◽  
pp. 1613-1617 ◽  
Author(s):  
Laurent Poirel ◽  
Wejdene Mansour ◽  
Olfa Bouallegue ◽  
Patrice Nordmann
Keyword(s):  
Amino Acid ◽  
Acinetobacter Baumannii ◽  
Amino Acid Substitution ◽  
Multidrug Resistant ◽  
Single Amino Acid Substitution ◽  
Single Amino Acid ◽  
The Novel ◽  
Cloning And Sequencing ◽  
Carbapenem Resistant ◽  
Genetic Structures

ABSTRACT The basis of the β-lactam resistance of 39 multidrug-resistant Acinetobacter baumannii isolates recovered from hospitalized patients was studied. These isolates were collected from 2001 to 2005 at the Sahloul Hospital in Sousse, Tunisia. They belonged to two distinct clones. One clone that grouped 19 isolates produced a carbapenem-hydrolyzing oxacillinase, OXA-97, that differed from OXA-58 by a single amino acid substitution and conferred the same β-lactam resistance profile as OXA-58. The bla OXA-97 gene was located on plasmids that varied in size in 18 isolates and was chromosomally located in a single isolate. Cloning and sequencing identified genetic structures surrounding the bla OXA-97 gene similar to those reported to be adjacent to the bla OXA-58 gene. In addition, the novel ISAba8 element (which is of the IS21 family) was identified. This is the first report of the nosocomial spread of carbapenemase producers in A. baumannii isolates in Africa.

scholarly journals Genetic Structures at the Origin of Acquisition and Expression of the Carbapenem-Hydrolyzing Oxacillinase Gene blaOXA-58 in Acinetobacter baumannii

2006 ◽  
Vol 50 (4) ◽  
pp. 1442-1448 ◽  
Author(s):  
Laurent Poirel ◽  
Patrice Nordmann
Keyword(s):  
Genetic Structure ◽  
Acinetobacter Baumannii ◽  
Type Strain ◽  
Insertion Sequence ◽  
Promoter Sequences ◽  
Sequence Elements ◽  
Genetic Structures ◽  
Novel Structures ◽  
Insertion Sequence Elements ◽  
Plasmid Backbone

ABSTRACT Genetic structures surrounding the carbapenem-hydrolyzing oxacillinase gene bla OXA-58 were characterized in a series of OXA-58-positive Acinetobacter baumannii strains isolated from different countries. We showed that in most of the cases, acquisitions of the bla OXA-58-containing overall structure, including insertion sequence elements, may be likely the results of recombination events. In type strain A. baumannii MAD, the genetic structure surrounding the bla OXA-58 gene was bracketed by two 27-bp repeated sequences. The isolation of a clonally related OXA-58-negative A. baumannii isolate that possessed the same plasmid backbone as A. baumannii MAD but lacked this genetic structure indicated that the mechanism of acquisition could be reversible. Parts of the structure identified in A. baumannii MAD were conserved in other bla OXA-58-positive isolates from various European countries. Primer extension experiments showed that bla OXA-58 expression was related to promoter sequences brought by different insertion sequence elements, such as an ISAba3-like element, ISAba1, ISAba2, and IS18. This work identified novel structures at the origin of acquisition and expression of a carbapenem-hydrolyzing β-lactamase identified in non-clonally related A. baumannii isolates.

scholarly journals Genetic and Functional Analysis of the Chromosome-Encoded Carbapenem-Hydrolyzing Oxacillinase OXA-40 of Acinetobacter baumannii

2003 ◽  
Vol 47 (1) ◽  
pp. 268-273 ◽  
Author(s):  
Claire Héritier ◽  
Laurent Poirel ◽  
Daniel Aubert ◽  
Patrice Nordmann
Keyword(s):  
Acinetobacter Baumannii ◽  
Nucleotide Substitution ◽  
Hydrolytic Activity ◽  
Cloning And Expression ◽  
Mutant Enzyme ◽  
Gene Encoding ◽  
Narrow Spectrum ◽  
Class D ◽  
Lactamase Gene ◽  
Dna Mutagenesis

ABSTRACT Clinical isolate Acinetobacter baumannii CLA-1 was resistant to a series of antibiotic molecules, including carbapenems. Cloning and expression of the β-lactamase gene content of this isolate in Escherichia coli DH10B identified a chromosome-encoded oxacillinase, OXA-40, that differed by one or two amino acid changes from OXA-24, -25, and -26 and an AmpC-type cephalosporinase. The OXA-40 β-lactamase had a mainly narrow-spectrum hydrolytic profile, but it included ceftazidime and imipenem. Its activity was resistant to inhibition by clavulanic acid, tazobactam, sulbactam, and, like most of the other carbapenem-hydrolyzing oxacillinases, NaCl. OXA-40 had an FGN triad replacing a YGN motif at class D β-lactamase (DBL) positions 144 to 146. Site-directed DNA mutagenesis leading to a Phe-to-Tyr change at DBL position 144 in OXA-40 gave a mutant enzyme with increased hydrolytic activity against most β-lactams, including imipenem. Conversely, with a gene encoding the narrow-spectrum oxacillinase OXA-1 as the template, a nucleotide substitution leading to a Tyr-to-Phe change in the YGN motif of OXA-1 gave a mutant enzyme with decreased hydrolytic activity without an increase in carbapenem-hydrolyzing activity. Thus, the Phe residue in the FGN motif was not associated with carbapenem-hydrolyzing activity by itself but instead was associated with weak overall hydrolytic activity. Finally, this Phe residue in OXA-40 explained resistance to inhibition by NaCl whereas a Tyr residue in motif YGN was related to susceptibility to NaCl.

scholarly journals Discrimination of hospital isolates of Acinetobacter baumannii using repeated sequences and whole genome alignment differential analysis

2021 ◽  
Author(s):  
Roman Kotłowski ◽  
Alicja Nowak-Zaleska ◽  
Grzegorz Węgrzyn
Keyword(s):  
Acinetobacter Baumannii ◽  
Time Frame ◽  
Repeated Sequences ◽  
Hospital Environment ◽  
Genome Alignment ◽  
Whole Genome ◽  
Differential Analysis ◽  
Gene Encoding ◽  
Resistance Patterns ◽  
Whole Genome Alignment

AbstractAn optimized method for bacterial strain differentiation, based on combination of Repeated Sequences and Whole Genome Alignment Differential Analysis (RS&WGADA), is presented in this report. In this analysis, 51 Acinetobacter baumannii multidrug-resistance strains from one hospital environment and patients from 14 hospital wards were classified on the basis of polymorphisms of repeated sequences located in CRISPR region, variation in the gene encoding the EmrA-homologue of E. coli, and antibiotic resistance patterns, in combination with three newly identified polymorphic regions in the genomes of A. baumannii clinical isolates. Differential analysis of two similarity matrices between different genotypes and resistance patterns allowed to distinguish three significant correlations (p < 0.05) between 172 bp DNA insertion combined with resistance to chloramphenicol and gentamycin. Interestingly, 45 and 55 bp DNA insertions within the CRISPR region were identified, and combined during analyses with resistance/susceptibility to trimethoprim/sulfamethoxazole. Moreover, 184 or 1374 bp DNA length polymorphisms in the genomic region located upstream of the GTP cyclohydrolase I gene, associated mainly with imipenem susceptibility, was identified. In addition, considerable nucleotide polymorphism of the gene encoding the gamma/tau subunit of DNA polymerase III, an enzyme crucial for bacterial DNA replication, was discovered. The differentiation analysis performed using the above described approach allowed us to monitor the distribution of A. baumannii isolates in different wards of the hospital in the time frame of several years, indicating that the optimized method may be useful in hospital epidemiological studies, particularly in identification of the source of primary infections.

scholarly journals Molecular Characterization of the Gene Encoding a New AmpC β-Lactamase in a Clinical Strain of Acinetobacter Genomic Species 3

2004 ◽  
Vol 48 (4) ◽  
pp. 1374-1378 ◽  
Author(s):  
Alejandro Beceiro ◽  
Lourdes Dominguez ◽  
Anna Ribera ◽  
Jordi Vila ◽  
Francisca Molina ◽  
...  
Keyword(s):  
Nucleotide Sequence ◽  
Molecular Characterization ◽  
Biochemical Properties ◽  
Clinical Strain ◽  
The Novel ◽  
Gene Encoding ◽  
Genomic Species ◽  
First Time

ABSTRACT A presumptive chromosomal cephalosporinase (pI, 9.0) from a clinical strain of Acinetobacter genomic species 3 (AG3) is reported. The nucleotide sequence of this β-lactamase shows for the first time the gene encoding an AmpC enzyme in AG3. In addition, the biochemical properties of the novel AG3 AmpC β-lactamase are reported

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