“…The infecting organisms in the majority of the cases are Escher ichia coli bacteria belonging to a rather limited number of serological groups [1,12,15]. A large group of patients having a first attack of UTI attracts recurrences, often numerous, and in this group the risk for devel opment of renal parenchymal reduction and scarring seems appreciable [8,9], 1 Presented in part at the '3. Internationale Arbeitstagung über Probleme der Pyelonephritis', Bad Salzuflen, BRD, October 1970 [7).…”