Gynaecology & Obstetrics The commonest pathogen responsible for acute pyelonephritis in pregnancy is: A Escherichia coli B Klebsiella pneumoniae C Proteus mirabilis D Pseudomonas aeruginosa 💡 Explanation The commonest pathogen responsible for acute pyelonephritis in pregnancy is: ✓ Correct Answer: A. Escherichia coli