Clonal diversity of OXA-23 producing Acinetobacter baumannii isolates from Rio de Janeiro, Brazil

Abstract number: P1301

Grosso F., Quinteira S., Ramos A., Assef A., Carvalho K., Asensi M., Peixe L.

Objectives: Multidrug-resistant (MDR) Acinetobacter baumannii (Ab) are a leading cause of nosocomial infections in Brazilian hospitals, being OXA-23 producers disseminated in several hospitals.

The aim of this study was to assess the diversity of OXA-23-producing Ab isolates disseminated throughout hospitals in Rio de Janeiro (2006–2007) and to analyse blaOXA-23 carrying genetic structure.

Methods: From a collection of 96 OXA-23 producing Ab recovered in 8 hospitals (January 2006 to September 2007) from Rio de Janeiro, Brazil, isolates representative of different pulsotypes (n = 5) were selected for further characterization. Susceptibility tests and identification by rDNA sequencing were performed. Pulsotypes were determined by PFGE with ApaI. The genomic location of the bla OXA-23 gene was determined by I-CeuI technique and with PCR using specific primers for the composite transposon Tn2006. MLST scheme was conducted according to the Ab MLST database ( The blaOXA-51 type was identified by PCR and sequencing.

Results: Ab isolates were resistant to several b-lactams, presenting variable susceptibility to amikacin (clones A and E were susceptible), kanamycin and sulfamethoxazole/trimethoprim (clone E was susceptible). In all isolates, the blaOXA-23 gene was inserted in Tn2006 and located on the chromosome. The 5 pulsotypes clustered in 4 different STs that presented 4 new allelic combinations and 2 new gpi alleles. These new allelic profiles were related to other STs found in Latin America, but not related with ST22, already described in several European countries and Korea which is also associated to OXA-23 producers. Genotype A (69% of the OXA-23 producing isolates), the most prevalent and found in seven hospitals, was assigned in the same ST of clone D (1%) both presenting blaOXA-66. Genotypes B (25%) C (4%) and E (1%) presented blaOXA-132, blaOXA-95 and blaOXA-69, respectively.

Conclusions: This is the first study describing the population structure of MDR OXA-23-producing Ab clones in Brazil. Our findings indicate an ongoing spread of blaOXA-23 associate to new and diverse ST of A. baumannii in hospitals of Rio de Janeiro. The identification of the blaOXA-66 as the predominant lineage confirms its ability to disseminate and establish in the hospital setting.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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