AbaR-type resistance islands in multidrug resistance Acinetobacter baumannii (MDRAb) isolates

RAMÍREZ M.S., VILACOBA E., STIETZ M.S., LIMANSKY A.S., MÁRQUEZ C., CERQUETTI C., CATALANO M., CENTRÓN D.

Congreso; 94- XLVII Reunión Anual de la Sociedad Sociedad Argentina de Investigaciones Bioquímcas y Biología Molecular; 2011

Over the past years, MDRAb isolates have been reported with increasing frequency. The acquisition of resistance has been correlated with the large number of resistant determinants in its genome. The aim of this study was to determine the occurrence of the AbaR-type genomic island and its association with class 1 integrons MDRAb isolates. 52 MDRAb isolates recovered from several hospitals at different years and belonging to unrelated clones were included. The presence and structure of the island were determined by an AbaR1-based PCR mapping. Class 1 integrons location was investigated by PCR amplification. AbaR-type genomic resistance islands were present in 37/52 MDRAb isolates. PCR mapping showed different arrays to those previously described, evidencing the high variability of the AbaR-type islands. Class 1 integrons were found in 13 isolates. In 9 isolates (69%) class 1 integrons were located inside the island, and in 3 isolates we identified its plasmid location. Accordingly to MLST, isolates carrying AbaR-type islands were grouped at least in 3 clonal complexes and 5 new singletons. A widespread distribution of the AbaR-type genomic island among novel clones of Ab has been identified. The high frequency of class 1 integrons inserted in the AbaR-type genomic island in our Ab population since 1986 suggests its preferential location and persistence over time of this genetic platform.