Nosocomial transmission of Serratia marcescens in a veterinary hospital due to contamination by benzalkonium chloride

Abstract

During a 1 yr period, S. marcescens was isolated from 50% of all contaminated i.v. catheters from dogs and cats in a large veterinary hospital. S. marcescens was also isolated from respiratory tracts, genitourinary tracts, skin and other sites in hospitalized animals. A total of 55% of the clinical isolates and 66% of the i.v. catheter isolates had the same API biochemical profile. The source of the S. marcescens was determined to be aqueous benzalkonium chloride (0.025%) sponge pots located in the intensive care unit, surgery rooms and outpatient clinic areas of the hospital. Of the 11 S. marcescens isolates submitted to the Centers for Disease Control, USA, for serotyping (6 from aqueous benzalkonium chloride sponge pots, 5 from i.v. catheters), 8 were identified as serotype O10:H11. All S. marcescens isolates were most frequently resistant to streptomycin, cephalothin and ampicillin. This study demonstrates that improper use of disinfectants plays an important role in the nosocomial transmission of S. marcescens.