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

Karah, Nabil; Dwibedi, Chinmay Kumar; Sjöström, Karin; Edquist, Petra; Johansson, Anders; Wai, Sun Nyunt; Uhlin, Bernt Eric

doi:10.1128/aac.02143-15

Cited by 57 publications

(51 citation statements)

References 64 publications

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“…WGS revealed that plasmid pAB-MAL-1 was 9,810 bp in size and belonged to the GR2 plasmid family. This plasmid was 99% identical to the recently published pA105-2 plasmid (GenBank accession number KR535993.1) recovered from an A. baumannii strain of ST636 (18). It showed strong similarity with plasmid p2ABST25 (GenBank accession number AEPA01000396.1) (19), differing only by the insertion of ISAba31 upstream of the bla OXA-72 gene (Fig.…”

Section: Resultssupporting

confidence: 55%

First Occurrence of OXA-72-Producing Acinetobacter baumannii in Serbia

Dortet

Bonnin

Bernabeu

et al. 2016

Antimicrob Agents Chemother

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e Here, we characterized the first OXA-72-producing Acinetobacter baumannii isolate (designated MAL) recovered from a urine sample from a Serbian patient. Antimicrobial susceptibility testing, plasmid analysis, and whole-genome sequencing (WGS) were performed to fully characterize the resistome of the A. baumannii MAL clinical isolate. The isolate was multidrug resistant and remained susceptible only to colistin and tigecycline. PCR analysis revealed the presence of the carbapenemase OXA-72, an OXA-40 variant. Extraction by the Kieser method revealed the presence of two plasmids, and one of these, a ca. 10-kb plasmid, harbored the bla OXA-72 gene. WGS revealed 206 contigs corresponding to a genome of 3.9 Mbp in size with a G؉C content of 38.8%. The isolate belonged to sequence type 492 and to worldwide clone II (WWCII). Naturally occurring ␤-lactamase-encoding genes (bla ADC-25 and bla OXA-66 ) were also identified. Aminoglycoside resistance genes encoding one aminoglycoside adenyltransferase (aadA2), three aminoglycoside phosphatases (strA, strB, aphA6), and one 16S RNA methylase (armA) conferring resistance to all aminoglycosides were identified. Resistance to fluoroquinolones was likely due to mutations in gyrA, parC, and parE. Of note, the resistome matched perfectly with the antibiotic susceptibility testing results.

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Section: Resultssupporting

confidence: 55%

First Occurrence of OXA-72-Producing Acinetobacter baumannii in Serbia

Dortet

Bonnin

Bernabeu

et al. 2016

Antimicrob Agents Chemother

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“…Recently, the AbGRI3-2 structure that includes both Tn 6180 and Tn 6179 was found in the isolate A071 (GenBank accession number KT317075) and named Tn 6279 35 . This study also reported that circular TU forms of AbGRI3-2 (Tn 6180 and Tn 6179 with only two copies of IS 26 ) as well as just AbGRI3-1 (Tn 6180 with one copy of IS 26 ) could be detected by PCR in this isolate.…”

Section: Resultsmentioning

confidence: 52%

Variants of AbGRI3 carrying thearmAgene in extensively antibiotic-resistantAcinetobacter baumanniifrom Singapore

Blackwell

Holt

Bentley

et al. 2017

J. Antimicrob. Chemother.

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Objectives: To investigate the context of the ribosomal RNA methyltransferase gene armA in carbapenem-resistant global clone 2 (GC2) Acinetobacter baumannii isolates from Singapore.Methods: Antibiotic resistance was determined using disc diffusion; PCR was used to identify resistance genes. Whole genome sequences were determined and contigs were assembled and ordered using PCR. Resistance regions in unsequenced isolates were mapped.Results: Fifteen GC2 A. baumannii isolated at Singapore General Hospital over the period 2004–11 and found to carry the armA gene were resistant to carbapenems, third-generation cephalosporins, fluoroquinolones and most aminoglycosides. In these isolates, the armA gene was located in a third chromosomal resistance island, previously designated AbGRI3. In four isolates, armA was in a 19 kb IS26-bounded transposon, designated Tn6180. In three of them, a 2.7 kb transposon carrying the aphA1b gene, designated Tn6179, was found adjacent to and sharing an IS26 with Tn6180. However, in these four isolates a 3.1 kb segment of the adjacent chromosomal DNA has been inverted by an IS26-mediated event. The remaining 11 isolates all contained a derivative of Tn6180 that had lost part of the central segment and only one retained Tn6179. The chromosomal inversion was present in four of these and in seven the deletion extended beyond the inversion into adjacent chromosomal DNA. AbGRI3 forms were found in available GC2 sequences carrying armA.Conclusions: In GC2 A. baumannii, the armA gene is located in various forms of a third genomic resistance island named AbGRI3. An aphA1b transposon is variably present in AbGRI3.

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“…A. baumannii constitutes an increasing threat to hospitalized patients worldwide due to its high predisposition to nosocomial transmission and failure to respond to antimicrobial treatment due to rapid acquisition of multidrug resistance [2]. This resistance includes non-susceptibility to carbapenems, and hence the bacteria are called carbapenem-resistant A. baumannii (CRAB).…”

Section: Introductionmentioning

confidence: 99%

“…The most common lineages (ICL1-3) were initially reported in Europe and the United States, but later also in several countries in other parts of the world [15]. According to studies conducted in several European countries, the majority of CRAB outbreaks in that region have been associated with ICL2 isolates harbouring the oxacillinase bla OXA-23 -like carbapenemase gene [2,12]. Epidemiological investigations have described dissemination of A. baumannii isolates belonging to clonal complex 92 (CC92), corresponding to ICL2, in two hospitals in northern Iran [14,16].…”

Section: Introductionmentioning

confidence: 99%