Asymptomatic bacteriuria (ASB} refers to the growth of �100,000 (105) colony-forming units/ml of a single type of bacteria from a
clean catch urine specimen in the absence of urinary tract infection symptoms Risk factors for ASB include pre-gestational diabetes
mellitus and multiparity The increased progesterone levels in pregnancy cause smooth muscle relaxation and ureteral dilation,
thereby increasing the risk for pyelonephritis and other obstetrical complications (eg, preterm delivery, low birth weight} from ASB.
Therefore, all patients at the initial prenatal visit are screened for ASB. Patients whose screening urine cultures are positive are
treated with antibiotics (Choice D). The most common pathogen is Escherichia coli. First-line antibiotics include cephalexin,
amoxicillin-clavulanate, and nitrofurantoin. A repeat urine culture is performed after antibiotic completion to determine clearance
of infection.
(Choice B) Fluoroquinolones are contraindicated in pregnancy due to the potential association with fetal bone deformities and
arthropathy.
(Choice C) Doxycycline and other tetracycline antibiotics are contraindicated in pregnancy as they interfere with fetal bone and tooth
development Children exposed to tetracycline in utero can develop grey discoloration of the teeth.
(Choice E) Trimethoprim-sulfamethoxazole is safe during the second trimester. It is contraindicated during the first trimester due to
interference with folic acid metabolism and should be avoided during the third trimester due to increased risk of neonatal kernicterus.
Educational objective:
All patients are screened and treated for asymptomatic bacteriuria at the initial prenatal visit due to the risk of pyelonephritis, preterm
birth and low birth weight associated with untreated asymptomatic bacteriuria. The most common pathogen is Escherichia coli. Firstline antibiotics include cephalexin, amoxicillin-clavulanate, and nitrofurantoin.
Nhận xét
Đăng nhận xét