Pseudomonas aeruginosa infection is a serious problem in patients hospitalized with cancer, cystic fbrosis (CF) and in intensive care units (ICUs). Twitch- ing motility contributes to the virulence of P. aeruginosa and permits colonization and infection of the respiratory tract. Genetic relatedness and cross-infection by multidrug-resistant (MDR) P. aeruginosa could be identifed by the random ampli- fed polymorphic (RAPD) ? PCR genotypic identifcation system.