Objective: The main objectives of this study were to assess the clonal relatedness of Acinetobacter baumannii carbapenem-resistant isolates recovered from the Iberian Peninsula and to investigate the production of carbapenemases. Methods: One hundred and sixty-two imipenem-resistant A. baumannii isolates were collected from 1998 to 2003 in three Portuguese university hospitals. An imipenem-resistant isolate (988FFP strain) recovered in 1995 from a smaller hospital unit, was also included, as well as an OXA-40-producing A. baumannii Spanish strain (SM28). Susceptibility tests were carried out by disc diffusion and Etest methods. DNA fingerprints were obtained by PFGE of ApaI-digested chromosomal DNA. Carbapenemase activity was determined by a bioassay and spectrophotometry. The detection of the bla_OXA-40 gene was conducted through PCR analysis, cloning and nucleotide sequencing. Results: All the isolates presented a similar multi-resistance pattern, including imipenem (MIC >32 mg/L). The Iberian isolates showed an identical PFGE pattern with minor band variations, including isolate 988FFP collected in 1995. PCR results revealed a bla_OXA-type gene in 65 isolates and nucleotide sequence analysis revealed the presence of the bla_OXA-40 gene in seven representative Portuguese isolates from the various geographically dispersed hospitals. Conclusions: Our results indicate that a multi-resistant epidemic clone of A. baumannii, carrying bla_OXA-40, is disseminated in the Iberian Peninsula, persisting in Portugal since 1995.

This study focused on the population structure of OXA-23-producing Acinetobacter baumannii clinical isolates from Rio de Janeiro, Brazil. The analysis included several genomic typing methods, including PFGE, two multilocus sequence typing (MLST) schemes, sequence group (SG) determination and bla_OXA-51-like sequencing. The genomic context of the bla_OXA-23 gene was also evaluated using I-CeuI hybridizations and PCR assays. Congruent clustering was obtained revealing four lineages. In accordance, four new sequence types (STs) (ST131, ST132, ST133 and ST134) were obtained with the MLST-OD scheme (associated with the Oxford Database) and four (ST79, ST15 and two new allelic profiles) with the MLST-IP scheme (developed by the Institute Pasteur). Four SGs (SG1, SG4 and two new profiles) were identified, allowing the association of 70% of the isolates with European clone II. bla_OXA-51-like sequencing revealed the presence of bla_OXA-66, bla_OXA-69, bla_OXA-95 and bla_OXA-132. Identification of new STs together with new SG profiles are findings suggestive of a local diversity hotspot that is worth exploring.

The spread of OXA-24/OXA-40 (OXA-24/40)-producing Acinetobacter spp. in the Iberian Peninsula has been strongly influenced by clonal expansion, but the role of horizontal gene transfer has scarcely been explored. bla _OXA-24/40 -carrying plasmids and genetic environments were characterized in representative ( n = 15) Acinetobacter species clinical isolates (obtained between 2001 and 2007) by Acinetobacter baumannii PCR-based replicon typing, sequencing, hybridization, and restriction fragment length polymorphism. Besides the identification of bla _OXA-24/40 within the chromosomes of some isolates, the circulation of common bla _OXA-24/40 -carrying plasmids (30-kb repA_AB ; 10-kb aci2 ) and genetic backbones among Acinetobacter spp. was demonstrated.

Information on clonal lineages and genetic platforms involved in the mobilization of carbapenemases between Pseudomonas aeruginosa strains in Portugal is scarce. Here, we outline the genetic drivers contributing to the occurrence of bla_VIM-2-producing P. aeruginosa over two decades. A collection of carbapenem-resistant P. aeruginosa clinical isolates (n = 263, 1995–2014) was screened for carbapenemase production by Blue-Carba and PCR. Antimicrobial susceptibility testing was performed according to EUCAST and clonal analysis by MLST. Nine isolates representing different integrons and STs were selected for WGS, followed by bioinformatics. Twenty-seven bla_VIM-2-producing P. aeruginosa belonging to 10 STs were identified, with ST179 and ST111 being the most prevalent and persistent clones. bla_VIM-2 was associated with seven class I integrons frequently co-harbouring aminoglycoside resistance genes. In58 was commonly identified, followed by derivatives and In100. bla_VIM-2-harbouring transposons of the Tn3 and Tn402 families were linked to different plasmids or integrative conjugative elements of the clc family. The dissemination of bla_VIM-2 carrying integrons is associated with a complex interplay between different mobile genetic elements, including the overlooked integrative conjugative elements, and successful spread of particular clones.