Serratia marcescens has been reported to be associated with infections of the lungs,1,2 meninges,3 endocardium,4 burns,5 and urinary tract,6 although its pathogenic role was not clearly defined in every instance. It has also been seen without apparent infection in the intestinal tract of the newborn.7 The isolation of Serratia from the urine of 20 further patients is recorded here, and some evidence is given as to its etiological role in cases of urinary tract infection.
Methods and Materials
Patients were selected for study when organisms with the characteristics of Serratia were isolated from urine specimens sent to the laboratory for culture. Infection was considered present when organisms were cultured in moderate amounts from clean-caught or catheterized urine and over 10 WBC per high power field of urine sediment were seen. A moderate growth of bacteria was that amount which grew in heavy growth into