Enhanced chemotaxis to gentamicin-resistant strains of Pseudomonas aeruginosa.

The chemotactic response of human polymorphonuclear leukocytes (PMNLs) to gentamicin-sensitive and gentamicin-resistant strains of Pseudomonas aeruginosa was studied. Filtrates from the resistant strains markedly enhanced the chemotactic response of human PMNLs (leukotactic index [LI] = 40.4 micron), in contrast to the filtrates from the sensitive strains, which induced less migration of PMNLs (LI = 26.8 micron). This finding may explain previous observations that suggested that gentamicin-resistant strains of P. aeruginosa are less virulent than gentamicin-sensitive strains.