Gestational pyelonephritis--associated Escherichia coli isolates represent a nonrandom, closely related population.

Abstract

A select group of Escherichia coli strains known as uropathogenic cause pyelonephritis in nonpregnant individuals. We investigated whether Escherichia coli from gestational pyelonephritis represent a random population or possess common uropathogenic characteristics. Repetitive element sequence-based polymerase chain reaction, plasmid profiles, hemolysin, and O serotypes were assayed from Escherichia coli isolates of 57 pregnant patients with acute pyelonephritis at different gestational ages. The majority of the first trimester isolates fell primarily into repetitive element sequence-based patterns 1 and 3 and O6, O15, and O75 serotypes. Second-trimester isolates had multiple patterns with high-frequency repetitive element sequence-based polymerase chain reaction 1 and 5 and an unknown (OX) serotype. Pattern 3, predominantly O75 serotype, was found primarily among third-trimester isolates. It is likely that Escherichia coli associated with acute pyelonephritis during different trimesters of pregnancy represents nonrandom closely related isolates, and some of these strains may be characteristic in pregnant patients only.