Screening and treatment for ASB are not typically performed in the general population because they do not decrease the rates of symptomatic infection or adverse outcomes. In contrast, pregnant women.
In pregnancy, increased progesterone levels cause smooth muscle relaxation and ureteral dilation allows bacteria to ascend to the upper urinary tract. Because of these physiologic changes, pregnant women with untreated ASB are at increased risk for acute pyelonephritis and subsequent complications, including acute respiratory distress syndrome, low birth weight and preterm labor and delivery.
The lack of risk factors (eg, urinary tract anomalies, sickle cell disease) and a negative culture in the first trimester make rescreening unnecessary.
| Definition | • ≥100,000 CFU/mL of a single bacterium from a clean-catch urine specimen in the absence of symptoms of a urinary tract infection. |
|---|---|
| Risk factors | • Pregestational diabetes mellitus |
| • History of urinary tract infection | |
| • Multiparty | |
| Common pathogens | • Escherichia coli (most common) |
| • Klebsiella | |
| • Enterobacter | |
| • Group B Streptococcus | |
| Potential complications | • Acute pyelonephritis ( 40% risk ) |
| • Preterm labor & delivery | |
| Treatment | • First line→ choice depends on gestational age. |
• Fosfomycin
• Nitrofurantoin (Avoided in first & third trimesters)
• TMP-SMX (avoided in first & third trimesters)
if contraindications (ie, medication allergies) exist • Second line→rising bacterial resistance may limit their utility. • Cefpodoxime, cephalexin • Amoxicillin-clavulanate | | | As a test of cure, a repeat urine culture is performed after antibiotic treatment due to the risk for persistent or recurrent bacteriuria. Women with persistent bacteriuria should receive another course of antibiotic therapy based on the follow-up culture results. |
<aside> 💡 Although ASB increases the risk for preterm labor, it does not inherently prolong membrane rupture or labor; therefore, it is not a direct risk factor for IAI.
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Trimethoprim-sulfamethoxazole is safe in the second trimester but contraindicated in the first because it interferes with folic acid metabolism, which is critical to early fetal development. It is also contraindicated in the third trimester due to the risk for neonatal kernicterus.
Fluoroquinolone (eg, ciprofloxacin) are contraindicated in pregnancy due to the potential association with fetal bone deformities and arthropathy.
Doxycycline and other tetracycline antibiotics are contraindicated in pregnancy because they interfere with fetal bone and tooth development. Children exposed to tetracycline in utero can also develop gray discoloration of the teeth.
(choice A) Urinalysis should be obtained in pregnant women who present with symptoms of a UTI (e.g., dysuria, urinary urgency, urinary frequency). Although urinalysis offers extensive information on blood cells and microbes in the urine, it is not necessary for the follow-up evaluation of patients who had asymptomatic bacteriuria during pregnancy.