Effect of subminimal inhibitory concentration of Aminoglycosides on some Gram-Negative Bacilli

ABSTRACT

The effect of pre-incubation of Ps. aeruginosa and E. coli with subminimal inhibitory concentrations [sub-MICs] of tobramycin and amikacin on the adherence of these organisms was studied. Pre-incubation with sub-MICs of tobramycin or amikacin significantly enhanced the adherence for Ps. aeruginosa and decreased adherence for E. coli. Furthermore, the effect of pre-incubation with sub-MICs of tobramycin or amikacin on polymorphonuclear leukocyte [PMNLs] function against these organism was determined. Filtrates of E. coli pre-incubated with sub-MICs of tobramycin or amikacin promoted PMNL chemotaxis. No effect on chemotaxis was noted with the filtrates of Ps. aeruginosa pre-incubated with tobramycin or amikacin. Phagocytosis and intracellular killing for both organisms were increased after they were pre-incubated with sub-MICs of tobramycin or amikacin