Antimicrobial resistance determinants and mobile elements in Acinetobacter baumannii isolates recovered from different hospital during the year 2014

GERMÁN TRAGLIA; SABRINA MONTAÑA; B FUENTES; D ALVAREZ; M ALMUZARA; M PENNINI; CECILIA RODRÍGUEZ; A FERNANDEZ; M CATALANO; MARCELO TOLMANSKY; DANIELA CENTRÓN; A SUCARI; MARÍA SOLEDAD RAMÍREZ

New Orleans, Louisiana

Congreso; 115th General Meeting, American Society for Microbiology; 2015

ASM, American Society for Microbiology

A. baumannii, an important pathogen because its extreme genome plasticity, coupled with horizontal genetic transfer, allows it to acquire antibiotic resistance determinants or genes at an accelerated rate. To prevent the acquisition of more resistance genes and deal with the existing ones we must understand the mechanisms available in this bacterium to incorporate new resistance determinants. In the present study a molecular surveillance of different elements related to antibiotic resistance was performed. Sixty recent multi-drug or extensively-drug resistance clinical A. baumannii isolates collected from 9 different hospitals during 2014 were tested. The screening of 22 different genes or elements involved in antibiotic resistance was performed by PCR reaction and sequencing. Pan-PCR assay and/or MLST were used as markers for the isolates genetic relationship. Results indicated that the following resistance genes and insertion sequences (IS) were present in more than the 80% of the isolates: sul2, aacC2, blaOXA-23, strB, IS26, ISAba1, IS6018. blaOXA-23 was present in 95% of the isolates, while blaOXA-58 was present only in two isolates. Moreover, ISCR2 was present in 72% of the isolates. Class 1 integrons were found in 6 isolates, and class 2 integrons ?element that used to be prevalent among Argentinian isolates- was found only in 7 isolates. The AbaR-like type island was present in 45 % of the isolates. Regarding to the clonal complexes (CC) found among the isolates, we observed a prevalence of CC110 followed by CC109. None of the isolates belonged to the CC113, the prevalent clonal complex in previous years. This result clearly shows a shift in the lineages that are currently circulating in our region. In addition to the CC shift observed in our region, we conclude that: i) the recent isolates contain a variety of resistance determinants, ii) blaOXA-23 is the predominant carbapenemase in our region, and iii) the role of ISs in the dissemination and expression of genes pointed them as the predominant mobile elements related to the acquisition of antimicrobial resistance present in A. baumannii. Hence, a continuous genetic surveillance of A. baumannii is needed in every region to assess the dynamic of the genetic population of this species and the antimicrobial resistance local pattern.