3.3 Genomic antibiotic resistance and virulence characteristics of the P. aeruginosa AUST-03 isolates
Whole genome sequencing of the 11 P. aeruginosa AUST-03 study strains showed that the main genomic basis of antibiotic resistance in the P. aeruginosa isolates was efflux pump mediated. Genes conferring the MexAB-OprM, MexCD-OprJ, MexEF-OprN, MexXY-OprM efflux pumps were detected in all of the study strains and mutations in themexR, mexT, nalC and nfxB genes were detected in all of the strains that conferred the up-regulation of these efflux pumps. Additional efflux pumps emrE and pmpM genes were also detected in all of the study strains that confer resistance to fluoroquinolones and aminoglycosides, respectively. The antibiotic resistance genes (ARGs): blaOXA-50 ,blaOXA-1034 , blaPDC-3 ,blaPDC-374 and crpP were also found in all of the strains, however, these genes are considered to play a minor role in P. aeruginosa antibiotic resistance. Acquired mutations in genes were found in the strains that conferred resistance to fluoroquinolones [gyrA (3/11), gyrB (8/11) andparE (1/11)] and colistin [pmrAB (11/11)]. Details on the major antibiotic resistance determinants of theP. aeruginosa AUST-03 strains from the study have been illustrated in Figure 1.