HIGHER AMINOGLYCOSIDE RESISTANCE IN MUCOID PSEUDOMONAS AERUGINOSA THAN IN NON-MUCOID STRAINS

Background- Pseudomonas aeruginosa is an important opportunistic pathogen. The mucoid strains of this organism produce a hyperviscous glycocalyx (alginate) that provides a barrier against antimicrobial agents and the immune system, thereby increasing its virulence and antibiotic resistance. Methods- The in vitro activities of gentamicin, tobramycin and amikacin against 133 clinical isolates of Pseudomonas aeruginosa were tested by a disk diffusion method. The Muir method was used for capsule staining and identifying mucoid and non-mucoid strains. Results- The mucoid strains (n = 43) were statistically significantly more resistant to amikacin, gentamicin and tobramycin than the non-mucoid strains (n = 90) (p = 0.001, 0.0002 and 0.009, respectively). Conclusion- Mucoid strains of Pseudomonas aeruginosa were more resistant to gentamicin, amikacin and tobramycin than non-mucoid strains. Therefore, these antimicrobial agents should be avoided in the treatment of mucoid Pseudomonas aeruginosa infections.