The Ecology of R Factors

THE ability of many gram-negative bacilli to resist certain commonly used antibiotics has been shown to be mediated in large part by R factors. Since the incidence of infections caused by gram-negative bacilli has been increasing, and since R factors can mediate multiple-drug resistance, and can be transferred between bacteria, these extrachromosomal genetic elements have concerned public-health workers and interested microbiologists.In this issue of the Journal, Davis and Anandan report the recovery of Escherichia coli with R factors from an "antibiotic virgin" community in Borneo. Their findings confirm and extend those of other studies1 , 2 indicating that resistant, and . . .