RT Journal Article SR Electronic T1 Interspecies DNA acquisition by a naturally competent Acinetobacter baumannii strain JF bioRxiv FD Cold Spring Harbor Laboratory SP 308833 DO 10.1101/308833 A1 German M. Traglia A1 Kori Place A1 Cristian Dotto A1 Jennifer S. Fernandez A1 Camila dos Santos Bahiense A1 Alfonso Soler-Bistue A1 Andres Iriarte A1 Marcelo E. Tolmasky A1 Robert A Bonomo A1 Roberto G. Melano A1 María Soledad Ramírez YR 2018 UL http://biorxiv.org/content/early/2018/04/26/308833.abstract AB Acinetobacter baumannii is a human pathogen that frequently acquires antibiotic resistance genes leading to the emergence of multi-drug-resistant (MDR) strains. To investigate the role of transformation in the acquisition of resistance determinants by this species, the susceptible strain A118 was exposed to genomic DNA of carbapenem-resistant Klebsiella pneumoniae (CRKp). Resistant transformants were obtained and an increase in the resistance level to all β-lactam antibiotics was observed. Whole genome analysis of transformant clones demonstrated the acquisition of CRKp DNA. The most frequently acquired genes correspond to mobile elements, antibiotic resistance genes, and operons involved in metabolism. Bioinformatic analyses and in silico gene flow prediction strengthen our findings, showing that a continuing exchange of genetic material between A. baumannii and K. pneumoniae occurs when they share the same niche. Our results reinforce the idea that natural transformation may play a key role in the increasing emergence of A. baumannii MDR.IMPORTANCE Since the characterization of antibiotic resistance in the late ‘50s, antibiotic resistance propagation was classically associated with horizontal gene transfer (HGT) mediated by plasmids bearing multiple resistance genes. Here we show that, at least in the human pathogen A. baumannii, transformation also plays a major role in the acquisition of antibiotic resistance determinants. This study unravels that at least for certain pathogens the propagation of resistance genes occurs by alternative HGT mechanisms which in the past have been unappreciated.