Presence of OXA-type enzymes in Achromobacter species different from A. xylosoxidans

G. TRAGLIA; M. PAPALIA; M. ALMUZARA; D. CENTRÓN; G. GUTKIND; C. VAY; M. RADICE; MS RAMÍREZ

Denver

Congreso; 53rd ICAAC (Intersciencie Conference on Antimicrobial Agents and Chemotherapy); 2013

American Society for Microbiology

Presence of OXA-type enzymes in Achromobacter species different from xylosoxidans   Background: A. xylosoxidans is recognized as capable of causing persistent respiratory tract infections in cystic fibrosis (CF) patients, although the pathogenic role of other species within  this genus has been recently reported. Besides, accurate species identification of Achromobacter isolates is difficult and clinical isolates of Achromobacter are mostly referred as A. xylosoxidans. In this study phenotype-based techniques and molecular tools were conducted to achieve a proper identification of 3 Achromobacter clinical isolates Methods: Phenotypic identification was performed by biochemical tests according to Yabuuchi et al, 1998 and Vandammme et al. 2012; and API 20 NE System (Biomerieux). Genotypic identification was performed by 16S rRNA gene amplification and sequencing. A MLST scheme was conducted to identify species of Achromobacter according to Spilker et al. 2012. The presence of the A. xylosoxidans species specific marker blaOXA-114 (Turton et al, 2011) was investigated by PCR amplification and sequencing. A TAIL-PCR approach was used to achieve the complete sequence of the blaOXA genes. Results: Biochemical tests were not conclusive to identify at the species level. The 16S rRNA gene sequence displayed more than 99% similarity to the sequences of the type strains of all species of Achromobacter. Allele profiles and sequence types (ST) were assigned according to http://pubmlst.org/achromobacter/. Two isolates corresponded to genogroups 2b (A114, A79) and one to genogroup 14 (A336). Positive PCR amplifications were obtained using the primers described by Turton et al, however amplicon sequence differed from blaOXA-114a in 87-89% of nucleotide identity (translated in 15-18 amino acid changes). The new OXA variants were deposited as EMBL JX306689, JX306688. The OXA variant found in the A79 corresponded to OXA243b. Conclusions: Here we report new OXA variants seemingly ubiquitous in the different species of Achromobacter spp. It is clear that not only A. xylosoxidans represents the genus in CF secretions, suggesting that the role of the other species needs to be reevaluated and that proper identification is absolutely necessary to understand the epidemiology.