Hospital Characteristics Associated With Colonization of Water Systems by Legionella and Risk of Nosocomial Legionnaires' Disease: A Cohort Study of 15 Hospitals

We share Dr. VanCouwenberghe's opinion about the importance of defining the nosocomial transmission dynamics of this microorganism. The precise definition of either environmental sources or cross-transmission as the causes of nosocomial infections is essential in order to adopt specific strategies in the management of patients and thus efficiently contain outbreaks. With regard to the proposal of using antibiotic susceptibility patterns to type this microorganism, in our case this approach was not possible, as all isolates were multiresistant and susceptible only to trimethoprim-sulfamethoxazole. Furthermore, in our institution, most of the S maltophilia isolates (70%) obtained in 1999 were susceptible to only trimethoprim-sulfamethoxazole (50%) or to aminoglycosides and quinolones (20%). This would limit seriously, in our context, the usefulness of applying susceptibility patterns for typing purposes. We consider that, today, molecular typing is a requirement for efficient management of nosocomial infections, and it should no longer be considered as a luxury tool restricted to refined epidemiological analysis. To fill the conceptual gap between these two realities, efforts should be made to increase personnel expertise in molecular techniques in the microbiology wards and to supply them with adequate resources. The reduction in expenses derived from more efficient management of nosocomial infections would easily finance "typing units" to provide immediate assistance to the bedside clinician.