THE ROLE OF SERRATIA-MARCESCENS IN SOFT CONTACT-LENS ASSOCIATED OCULAR INFECTIONS - A REVIEW

Serratia marcescens is a Gram negative rod which for a century and a h alf was considered a harmless saphrophyte. However, medical technology and the use of antibacterial agents have created ecological niches fo r this bacterium, which is now a medical problem. The bacterium is enc ountered in connection with contact lens keratitis, often associated w ith contaminated contact lens solutions. The concentrations of chlorhe xidin and thiomersal required in contact lens solution to suppress the bacterium have been proved toxic to the eye. Modern contact lens solu tions with biguanids have rapid killing kinetics, while in solutions w ith polyquaternium S. marcescens can survive in reduced numbers for up to 72 hours. The adherence of a specific isolate of Serratia to hydro gel lenses increased with decreased water content of the lenses. Howev er, there has been no correlation between hydrophobicity markers or he magglutinins and adherence to contact lenses or urinary tract epitheli um. When handling medical plastic devices, such as contact lenses, str ictly inforced hygiene remains the most important method to combat env ironmental bacteria such as Serratia marcescens.