Acinetobacter Genome sequencing and assembly. Acinetobacter

BackgroundAcinetobacter sp. has emerged as a significant pathogen causing nosocomial infections. Treatment of these pathogens has become a major challenge to all clinicians worldwide. Huge revenue and technology is also being dedicated towards developing novel drugs and antibiotic combinations to combat resistance. Addressing the above issue, we have constructed a panel of strains of Acinetobacter sp. expressing different resistances such as narrow spectrum β-lactamase and oxacillinase, ESBL, OXA-carbapenemase, MBL and over producing AmpC, and genotypically characterized them to understand their resistance mechanism.MethodsAll the bacterial strains exhibiting different resistance phenotypes were collected according to the diagnostic decision tree based on phenotypic observation mentioned in Courvalin, P., et al. Antibiogram, during the period 2008-2013 from Severance hospital, Seoul. Antimicrobial susceptibility was determined according to the CLSI guidelines using agar dilution method. Selected strains were sequenced using Ion Torrent PGM system, annotated using RAST server and analyzed using Geneious pro 8.0.ResultsGenotypic determinants i.e. acquired resistance genes, mutations and porin alternations contributing to the relevant expressed phenotype was characterized using massive parallel technology. The complete resistance mechanisms for the collected reference strains were determined. Due to the acquisition of multiple resistance genes and transposons, the diagnostic decision tree for evaluating the resistance is not accurate, which alarms the urgent need for modification to this scheme.ConclusionThe complete illustrated mechanism contributing to specific resistance phenotypes can be used as a target for the novel drug development. These strains can be used as a reference strain in the clinical laboratory and also in evaluating the anti-microbial drug efficiency for specific resistance. Similar work can also be performed in other species/genus to understand the mechanism and control the associated infections.