Evaluation of Antibiotic Tolerance inPseudomonas aeruginosafor Aminoglycosides and its Predicted Gene Regulations Through In-silico Transcriptomic Analysis

AbstractPseudomonas aeruginosacauses chronic infections like cystic fibrosis, endocarditis, bacteremia and sepsis, which are life-threatening and difficult to treat. The lack of antibiotic response inP. aeruginosais due to adaptive resistance mechanism, which prevents the entry of antibiotics into cytosol of the cell to achieve tolerance. Among different groups of antibiotics, aminoglycosides are used as a parental antibiotic for treatment ofP. aeruginosa. This study aims to determine the kinetics of antibiotic tolerance and gene expression changes inP. aeruginosaexposed to amikacin, gentamicin, and tobramycin. These antibiotics were exposed toP. aeruginosaat their MICs and the experimental setup was monitored till 72 hours, followed by the measurement of optical density in the interval of every 12 hours. The growth ofP. aeruginosain MICs of antibiotics represents the kinetics of antibiotic tolerance in amikacin, gentamicin, and tobramycin. Transcriptomic profile of antibiotic exposedP. aeruginosaPA14 was taken from Gene Expression Omnibus (GEO), NCBI as microarray datasets. The gene expressions of two datasets were compared by test versus control. Tobramycin exposedP. aeruginosafailed to develop tolerance in MICs 0.5µg/mL, 1µg/mL and 1.5µg/mL. Whereas amikacin and gentamicin treatedP. aeruginosadeveloped tolerance in MICs. This depicts the superiorin vitroresponse of tobramycin over the gentamicin and amikacin. Further,in silicotranscriptomic analysis of tobramycin treatedP. aeruginosaresulted in low expression of 16s rRNA Methyltransferase E, B & L, alginate biosynthesis genes and several proteins of Type 2 Secretory System (T2SS) and Type 3 Secretory System (T3SS). The Differentially Expressed Genes (DEGs) of alginate biosynthesis, and RNA Methyltransferases suggests increased antibiotic response and low probability of developing resistance. The use of tobramycin as a parental antibiotic with its synergistic combination might combatP. aeruginosawith increased response.