Relationship between Pigment Producibility and Drug Resistance in Serratia marcescens

Abstract

Among the clinical isolates of Serratia marcescens, non‐pigmented cells appeared more frequently from pigmented, drug‐resistant strains than from pigmented, drug‐sensitive strains. Transfer of R plasmid from Escherichia coli to pigmented strains caused spontaneous loss of pigment producibility, whereas such spontaneous loss never occurred in fresh cultures of drug‐sensitive strains. The non‐pigmented strain was a better recipient of R plasmid from E. coli than was the pigmented strain. R plasmid was transferred from the non‐pigmented strain to the pigmented strain at a higher frequency than from E. coli to the pigmented strain. The results of the present investigation suggest that transfer of R plasmid may be one of the reasons for the significant increase of non‐pigmented, drug‐resistant strains of S. marcescens in nature. © owned by Center for Academic Publications Japan (Publisher)