Although selection can be based on in vitro susceptibilities, in our extensive experience, empirical oral treatment for 10 days with nitrofurantoin macrocrystals, 100 mg at bedtime, is usually efective. Satisfactory results are also achieved with a 7-day oral course of nitrofurantoin, 100 mg given twice daily (Lumbiganon, 2009). Single-dose antimicrobial therapy is less successful (Widmer, 2015). The important caveat is that, regardless of regimen given, the recurrence rate is approximatey 30 percent.
This may indicate covert upper tract infection and the need for longer therapy. hus, after initial therapy, periodic surveillance is necessary to prevent recurrent urinary infections (Schneeberger, 2015).
For recurrent bacteriuria, we have had success with nitrofurantoin, 100 mg orally at bedtime for 21 days (Lucas, 1994). For women with persistent or frequent bacteriuria recurrences, suppressive therapy for the remainder of pregnancy can be given. We routinely use nitrofurantoin, 100 mg orally at bedtime. This drug may rarely cause an acute pulmonary reaction that dissipates on its withdrawal (Boggess, 1996).
TABLE 53-1. Oral Antimicrobial Agents Used for Treatment of Pregnant Women with Asymptomatic Bacteriuria
Amoxicillin,n3 9
Ampicillin,n2 9
Cephalosporin, 2 9
Nitrofurantoin, 200 mg Trimethoprim-sulfamethoxazole, 320/1600 mg
Amoxicillin, 500 mg three times daily Ampicillin, 250 mg four times daily Cephalosporin, 250 mg four times daily Ciprofloxacin, 250 mg twice daily
Levofloxacin, 250 or 500 mg daily Nitrofurantoin, 50 to 100 mg four times daily or 100 mg twice daily Trimethoprim-sulfamethoxazole, 160/800 mg twice daily
Nitrofurantoin, 100 mg four times daily for 10 days Nitrofurantoin, 100 mg twice daily for 5 to 7 days Nitrofurantoin, 100 mg at bedtime for 10 days
Nitrofurantoin, 100 mg four times daily for 21 days
Nitrofurantoin, 100 mg at bedtime for pregnancy remainder
Lower urinary infection during pregnancy may develop without antecedent covert bacteriuria (Harris, 1981). Cystitis produces dysuria, urgency, and frequency, but with few associated systemic indings. Pyuria and bacteriuria are usually found. Microscopic hematuria is common, and occasionally there is gross hematuria from hemorrhagic cystitis. Although cystitis is usually uncomplicated, the upper urinary tract may become involved by ascending infection. Almost 40 percent of pregnant women with acute pyelonephritis have preceding symptoms of lower tract infection (Gilstrap, 1981a).
Women with cystitis respond readily to any of several regimens. Most of the 3-day regimens listed in Table 53-1 are usually 90-percent efective (Fihn, 2003). Single-dose therapy is less efective, and if it is used, concomitant pyelonephritis must be confidently excluded.
Lower urinary tract symptoms with pyuria accompanied by a sterile urine culture may stem from urethritis caused by Chlamydia trachomatis. Mucopurulent cervicitis usually coexists, and azithromycin therapy is efective (Chap. 65, p. 1240).