This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Medical Illness Complicating Pregnancy, Subject name: Gynaecology & Obstetrics
The commonest pathogen responsible for acute pyelonephritis in pregnancy is: 
Select and explain. 
A. Escherichia coli, B. Klebsiella pneumoniae, C. Proteus mirabilis, D. Pseudomonas aeruginosa
A: Escherichia coli
Answer: A: Escherichia coli 
Explanation: E. coli is the common bacteria responsible for acute pyelonephritis in pregnancy It also causes asymptomatic bacteriuria. Urinary tract infection in pregnancy is a risk factor for threatened aboion, chorioamnionitis, preterm labor, IUGR.