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.