Whole genome sequence (WGS) analysis of an Acinetobacter baumannii minocycline resistant strain belonged to a new emerging MLST singleton?.

VILACOBA, ELISABET; ANDRES IRIARTE; SABRINA MONTAÑA; GERMAN MATIAS TRAGLIA; MAGDALENA PENNINI; ADRIANA SUCARI; MARIA SOLEDAD RAMIREZ

San Diego, California

Congreso; 55th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC); 2015

American Society for Microbiology

Background: Acinetobacter baumannii is recognized as a significant nosocomial pathogen being a focus of attention in clinical settings. Emergence of minocycline resistance and a shift in the prevalent clonal complex were observed in the past few years in Argentina. Because of these, we carried out WGS analysis of a minocycline resistant strain (A376), which belongs to a New sequence type (ST). Methods: MLST technique was performed. A draft sequence for A. baumannii A376 was obtaining using Illumina MiSeq. Denovo assembly was performed with the SPAdes assembler version 3.1.0. Annotation was carried out using RAST server and comparison with the closest neighbor was done using CONTIGuator server. Analysis of the predicted ORFs was carried out using BLAST server.  Results: A376 strain was classified as belonging to a new ST. The assembled contigs sum 4,208,545 bp. WGS comparison showed that ACICU strain is one of the closest neighbor strain (ANI =98%). RAST identified 3,913 possible ORFs. Genomic comparison between ACICU and A376 strains exposed a novel AbaR-type island. Eight ORFs corresponding to β-lactamases enzymes were identified. Different genes involved in antibiotic resistance such as AdeABC, AdeIJK, strA, strB, tet(B), tet(R) and sul2 were identified. These last genes were associated to ISCR2 in the same platform previously described by our group in minocycline resistant strains. A376 did not possess carO gene interrupted by insertion sequences. From the 36 alien islands described in ACICU strain, only 12, partially or complete, could be found in A376 strain. Forty-four ORFs corresponding to mobile elements were detected in A376 strain.  Conclusions: Antibiotic resistance mechanisms and different mobile elements have been found in the New ST strain including, drug efflux pumps and AbaR-type island . This analysis represents the start point to study the features of this particular singleton that will contribute to understand A. baumannii plasticity, epidemiology and antibiotic resistance mechanisms.