Rates of Stenotrophomonas maltophilia colonization and infection in relation to antibiotic cycling protocols

This study evaluated whether antibiotic cycling programmes using broad-spectrum agents including carbapenems were associated with increased rates of colonization or infection by Stenotrophomonas maltophilia. Retrospective analyses of colonization or infection by S. maltophilia from 1992 to 2002 were conducted using University of Virginia Hospital clinical microbiology records of patients with any culture positive for S. maltophilia and hospital epidemiology records of nosocomial S. maltophilia infections. Incidence rates were calculated and compared for cycling and non-cycling periods. No significant differences were found in incidence rates of S. maltophilia isolates between cycling and non-cycling periods, but there was a significant secular increase in the hospital-wide rate of infections caused by S. maltophilia (P=0.01728). Antibiotic cycling protocols were not associated with a significantly increased rate of colonization of S. maltophilia as determined by the frequency of patients having at least one positive routine clinical culture in this hospital.