About 15 strains of Pseudomonas aeruginosa isolated from cases of sinusitis were used in this study. Drug susceptibility pattern and molecular mechanisms of resistance were evaluated. Drug susceptibility was studied for the following antimicrobial agents. The antibiotics used were aminoglycosides - amikacin and gentamicin, the quinolones – ciprofloxacin and ofloxacin, the third generation cephalosporins - cefotaxime, the cefoperazone - sulbactam, cefpodoxime and other agents piperacillin and imipenem. Sensitivity to amikacin and gentamicin were observed in 11(73.3%) strains and resistance was observed in 4(26.6%) strains. It was observed that 4(26.6%) out of 15 strains were resistant to ciprofloxacin and 6(40%) were resistant to ofloxacin. To the cephalosporins, i.e to cefotaxime, cefoperazone - sulbactam and to cefpodoxime, 14(93.3%), 10(66.6%) and 12(80%) strains were resistant respectively. To piperacillin and imipenem, 14(93%) out of 15 strains were resistant. Plasmid was present in 67% of the Pseudomonas strains examined. PCR for IMP 1 was negative in all the strains tested. However, 9(60%) out of 15 strains were positive for VIM 1.
