Asymptomatic bacteriuria in healthy preterm babies.

Urine was cultured from 51 healthy preterm babies. If the initial bag specimen grew more than 50 000 organisms/ml, a second bag specimen was cultured. After two positive bag specimens a suprapubic urine was cultured. Significant bacteriuria was excluded on the basis of one or two bag specimens in 90% of the babies. Suprapubic urine was sterile in a further 11 babies. Four babies with positive bag specimens were unfortunately not completely investigated: 2 had mixed growths and 2 had pure growths of 100 000 organisms/ml. As we and others consider that bacteriuria can only be diagnosed on a suprapubic sample of urine the incidence of proved infection in our series was zero. If both the babies with a pure growth of 100 000 organisms/ml had true bacteriuria, the incidence would rise to 1.3%. In view of the difficulties in obtaining clean urine samples in preterm babies and as the incidence of bacteriuria is so low, we do not recommend that healthy preterm babies be screened for bacteriuria.