IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Objectives. The emergency of carbapenem-resistant Acinetobacter baumannii constitutes a worrisome problem worldwide. Aminoglycoside therapy is generally employed to treat carbapenem-resistant A. baumannii, but the rapid selection of aminoglycoside resista
Autor/es:
BROVEDAN, M; MARCHIARO, P.; MORAN-BARRIO, J.; BRAMBILLA, L; CERA, G.; RINAUDO, M; VIALE, A; LIMANSKY, A
Reunión:
Simposio; International Symposium on the Biology of Acinetobacter; 2015
Resumen:
Objectives. To report the first isolation in Argentina of a NDM-1-producing Acinetobacter bereziniae strain recovered from an immunocompromised inpatient, and the characterization of a plasmid containing blaNDM-1 from this strain including its comparison with reported Acinetobacter plasmids also carrying blaNDM-1. Methods. A carbapenem resistant Acinetobacter spp strain, HPC229, was isolated from a blood sample of a leukemic patient admitted on June 2014 into a public hospital of Rosario, Argentina. Its antibiotic susceptibility profile was determined by the VITEK-2 system, and the assignment at the species level was done by 16S rRNA, gyrB and rpoB comparisons. Metallo-β-lactamase genes were identified by PCR and sequencing, and the plasmid location of resistance genes was analyzed by plasmid curing with SDS and elevated temperature. Further plasmid characterization was done by pyrosequencing/database searching and conjugation assays. Results. HPC229 16S rRNA, gyrB, and rpoB genes showed the highest similarity to the corresponding orthologs of the A. bereziniae ATCC17924T type strain. HPC229 was resistant to all β-lactams tested including carbapenems, and PCR/sequencing analyses revealed the presence of blaNDM-1. This gene was located in plasmids as judged by the carbapenem sensitivity and negative testing for blaNDM-1 of the SDS-cured strain. This A. bereziniae plasmid was designated pNDM229, and sequence analysis revealed that blaNDM-1 is located within a Tn125 transposon. The immediate genetic environment of blaNDM-1 was found most similar to that of the conjugative plasmid pNDM-BJ01 from an A. lwoffii strain isolated in China, but in pNDM229 this structure is bracketed by ISAba14-like elements with an additional previously unreported downstream ISAba14 copy located within a putative adaptability module. Also, the transfer module of pNDM229 showed several truncated or absent genes which could account for conjugation failures. Conclusion. We report here the first case of a NDM-1-producing A. bereziniae strain in Argentina, whose dissemination could be driven by its linkage to Tn125 or ISAba14-like elements. To our knowledge only another NDM-1-bearing A. bereziniae strain isolated in India has been recently reported, with blaNDM-1 located in this case into a conjugative plasmid.