I URINARY TRACT INFECTIONS

More than one half of women will have a urinary tract infection (UTI) sometime in their life, which makes it one of the most common bacterial infections in adults. These infections may include asymptomatic bacter- uria, cystitis, or acute pyelonephritis.

A recurrent UTI is defined as either a relapse (infection with the same organism, usually within 2 weeks of completing treatment) or re-infection (infection with a different organism or the same organism after a negative intervening urine culture). Multiple recurrences occur in 3-5% of women. Most recurrences are re-infections rather than relapses. Risk factors for recurrent infection in premenopausal women include frequent intercourse, long-term spermicide use, diaphragm use, a new sexual partner, and young age (less than 15 years) at first UTI. Risk factors for recurrent UTIs in postmenopausal women differ from those in premenopausal women and include urinary incontinence, presence of a cystocele, vulvovaginal atrophy, and abnormal postvoid residual urine.

Evaluation and Diagnosis

Diagnosing UTIs in a timely manner should be within the purview of all women’s health care providers. A woman with acute bacterial cystitis will typically present with symptoms, including painful voiding, frequency, and urgent urination; she also may report suprapubic pain or pressure, hematuria, or discoloration of urine. Bacteruria (whether asymptomatic or associated with symptoms) is diagnosed with a clean-catch midstream urine sample. Leukocyte esterase or nitrite testing on urine dipstick is a reasonable screening test, but sensitivity is only 75%, so false-negatives may be common.

Urine culture is not necessary in all women with acute cystitis but should be performed if the diagnosis is unclear, if there is no clinical improvement

Box 4-12. Risk Factors for Urinary Tract Infection in Premenopausal and Postmenopausal Women ^

Premenopausal Women

• History of urinary tract infection

• Frequent or recent sexual activity

• Diaphragm use

• Use of spermicidal agents

• Increasing parity

• Diabetes mellitus

• Obesity

• Sickle cell trait

• Anatomic congenital abnormalities

• Urinary tract calculi

• Neurologic disorders or medical conditions that require indwelling or repetitive bladder catheterization

Postmenopausal Women

• Vaginal atrophy

• Incomplete bladder emptying

• Poor perineal hygiene

• Pelvic organ prolapse

• Lifetime history of urinary tract infection

• Type 1 diabetes mellitus

Modified from Treatment of urinary tract infections in nonpregnant women. ACOG Practice Bulletin No. 91. American College of Obstetricians and Gynecologists. Obstet Gynecol 2008;111:785-94.

within 48 hours of treatment, in the case of recurrence, and in all cases of upper tract infection. Women with frequent recurrences and prior con­firmation by diagnostic tests who are aware of their symptoms may be empirically treated without recurrent testing for pyuria.

Management

Screening for and treatment of asymptomatic bacteriuria is not recom­mended in nonpregnant, premenopausal women. Asymptomatic bac- teriuria has not been shown to be harmful in this population, nor does treatment of asymptomatic bacteriuria decrease the frequency of symp­tomatic infections.

Treatment of acute cystitis that is uncomplicated (ie, no underlying anatomic issue or medical condition) can be accomplished with 3-day therapy. Numerous studies have shown that 3-day antimicrobial regimens are usually as effective and better tolerated than longer treatment in pre­menopausal and postmenopausal women.

Pyelonephritis can be treated on an outpatient basis in healthy women who can tolerate oral medication and fluids. Standard therapy is 14 days (total) of oral or parenteral antibiotics; improvement in symptoms should be noted by 48-72 hours after initiating therapy. If the patient is not able to tolerate liquids or medication by mouth, hospital admission is required for intravenous hydration and antibiotics. Regardless of route of antibiot­ics, urine culture should be obtained before treatment. A urine culture test of cure usually is performed when the 2-week course of antibiotics is completed.

A major consequence of indiscriminate prescribing practices of common antibiotics is the emergence of antimicrobial resistance. Data from areas reporting antimicrobial susceptibility profiles have shown an alarming increase in the prevalence of resistance to amoxicillin and trimethoprim­sulfamethoxazole. Health care providers should be aware of community­specific or hospital-specific resistance data, and susceptibility testing should be used when needed to determine the choice of antibiotic. Escherichia coli

Table 4-6. Recommended First-Line Treatment Regimens for Uncomplicated Acute Bacterial Cystitis* ^

*The 2010 Infectious Diseases Society of America guidelines for the treatment of acute uncom­plicated cystitis recommend these as first-line antimicrobial treatment agents.

Data from Gupta K, Hooton TM, Naber KG, Wullt B, Colgan R, Miller LG, et al. International clini­cal practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: A 2010 update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases. Infectious Diseases Society of America. European Society for Microbiology and Infectious Diseases. Clin Infect Dis 2011;52:e103—20 and Treatment of urinary tract infections in nonpregnant women. ACOG Practice Bulletin No. 91. American College of Obstetricians and Gynecologists. Obstet Gynecol 2008;111:785-94. has been shown to be the causative pathogen in more than 80% of women. Other common pathogens include Staphylococcus saprophyticus, Klebsiella pneumoniae, Enterococcus, and Proteus mirabilis.

Recurrent UTIs can result in high utilization of health care services and frustration for the patient. In addition to lifestyle changes and reducing the use of spermicides, continuous prophylaxis for 6-12 months with once- nightly antibiotic treatment is reasonable. Postcoital prophylaxis with a single dose of a single agent also might decrease recurrences.

Bibliography

Gupta K, Hooton TM, Naber KG, Wullt B, Colgan R, Miller LG, et al. International clinical practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: A 2010 update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases. Infectious Diseases Society of America. European Society for Microbiology and Infectious Diseases. Clin Infect Dis 2011;52:e103-20. [PubMed] [Full Text]

Treatment of urinary tract infections in nonpregnant women. ACOG Practice Bulletin No. 91. American College of Obstetricians and Gynecologists. Obstet Gynecol 2008;111:785-94. [PubMed] [Obstetrics & Gynecology]

Resources

American College of Obstetricians and Gynecologists. Urinary tract infections. ACOG Patient Education Pamphlet AP050. Washington, DC: ACOG; 2008.

American College of Obstetricians and Gynecologists. Urogynecology: a case man­agement approach [CD-ROM]. Washington, DC: ACOG; 2005.

American Urogynecologic Society. Available at: http://www.augs.org. Retrieved August 15, 2013.

Infectious Diseases Society of America. Infections by organ system: genitourinary. Available at: http://www.idsociety.org/Organ_System/#Genitourinary. Retrieved August 15, 2013.

Jepson RG, Williams G, Craig JC. Cranberries for preventing urinary tract infections. Cochrane Database of Systematic Reviews 2012, Issue 10. Art. No.: CD001321. DOI: 10.1002/14651858.CD001321.pub5. [PubMed] [Full Text]