Chapter 23: Urinary Tract Infections

INTRODUCTION

Urinary tract infections (UTIs) are among the most common bacterial infections encountered in medicine. Accurately estimating incidence is difficult because UTIs are not reportable, but estimates range from 650,000 to 7 million office visits per year.

A UTI is defined by urologists as any infection involving the urothelium, which includes urethral, bladder, prostate, and kidney infections. Some of these are diseases that have been clearly characterized (eg, cystitis and pyelonephritis), whereas others (eg, urethral and prostate infections) are not as well understood or described.

The terms simple UTI and uncomplicated UTI are often used to refer to cystitis. In this chapter UTI is used to refer to any infection of the urinary tract, and cystitis is used to specify a bladder infection. The generic term complicated UTI is often used to refer to cystitis occurring in a person with preexisting metabolic, immunologic, or urologic abnormalities, including kidney stones, diabetes, and AIDS, or caused by multidrug resistant organisms.

Asymptomatic bacteriuria, uncomplicated cystitis, complicated cystitis, two urethral syndromes, four prostatitis syndromes, and pyelonephritis are discussed in this chapter. Although separated into different diagnoses, differentiating among syndromes and deciding treatment is left to the clinician’s discretion.

Antibiotic resistance is a topic that has been left mostly to the reader. General recommendations about specific antibiotics are inappropriate, given that antibiotic resistance differs from location to location. It is the responsibility of individual physicians to be familiar with local antibiotic resistances, and to determine the best first-line therapies for their practice. Always keep in mind that antibiotic use breeds resistance, and try to keep first-line drugs as simple and narrow-spectrum as possible.

ASYMPTOMATIC BACTERIURIA

General Considerations

Asymptomatic bacteriuria is defined separately for men, women, and the type of specimen. For women, clean-catch voided specimens on two separate occasions must contain >10⁵ CFU/mL of the same bacterial strain, or one catheterized specimen must contain >10² CFU/mL of bacteria. For men, a single clean-catch specimen with >10⁵ CFU/mL of bacteria or one catheterized specimen with >10² CFU/mL of bacteria suffices for the diagnosis. By definition, the patient must be asymptomatic, that is, should not be experiencing dysuria, suprapubic pain, fever, urgency, frequency, or incontinence. Screening for bacteriuria does not need to be done in young, healthy, nonpregnant women; elderly healthy or institutionalized men or women; diabetic women; persons with spinal cord injury; or catheterized patients while the catheter remains in place. Pregnant women are now the only group that should be routinely screened and treated for asymptomatic bacteriuria. There are multiple guidelines ...