- Urinary tract infections (UTIs) can be classified as uncomplicated and complicated. Uncomplicated refers to an infection in an otherwise healthy, premenopausal female who lacks structural or functional abnormalities of the urinary tract. Most often complicated infections are associated with a predisposing lesion of the urinary tract; however, the term may be used to refer to all other infections, except for those in the otherwise healthy, premenopausal adult female.
- Recurrent UTIs are considered either reinfections or relapses. Reinfection usually happens more than 2 weeks after the last UTI and is treated as a new uncomplicated UTI. Relapse usually happens within 2 weeks of the original infection, and is a relapse of the original infection either because of unsuccessful treatment of the original infection, a resistant organism, or anatomical abnormalities.
- Seventy-five to ninety-five percent of uncomplicated UTIs are caused by Escherichia coli and the remainder are caused primarily by Staphylococcus saprophyticus, Proteus spp., and Klebsiella spp. Complicated infections may be associated with other gram-negative organisms and Enterococcus faecalis.
- Symptoms of lower UTIs include dysuria, urgency, frequency, nocturia, and suprapubic heaviness, whereas upper UTIs involve more systemic symptoms such as fever, nausea, vomiting, and flank pain.
- Significant bacteriuria traditionally has been defined as bacterial counts of greater than 105 organisms (CFU)/mL (108/L) of a midstream clean catch urine. Many clinicians, however, have challenged this statement as too general. Indeed, significant bacteriuria in patients with symptoms of a UTI may be defined as greater than 102 organisms (CFU)/mL and go ahead and take out the 105/L.
- The goals of treatment of UTIs are to eradicate the invading organism(s), prevent or treat systemic consequences of infections, prevent the recurrence of infection, and prevent antimicrobial resistance.
- Uncomplicated UTIs can be managed most effectively with short-course (3 days) therapy with either trimethoprim–sulfamethoxazole, one dose of fosfomycin, or 5 days of nitrofurantoin. Due to the possibility of collateral damage, fluoroquinolones should be reserved for suspected pyelonephritis or complicated infections.
- In choosing appropriate antibiotic therapy, practitioners need to be cognizant of antibiotic resistance patterns, particularly to E. coli. Trimethoprim–sulfamethoxazole has diminished activity against E. coli in some areas of the country, with reported resistance in some areas greater than 20%.
- Acute bacterial prostatitis can be managed with many agents that have activity against the causative organism. Chronic prostatitis requires prolonged therapy with an agent that penetrates the prostatic tissue and secretions. Therapy with fluoroquinolone or trimethoprim–sulfamethoxazole is preferred for up to 6 weeks.
On completion of the chapter, the reader will be able to:
Define the differences between uncomplicated and complicated urinary tract infections (UTIs).
Identify the most common organisms that cause UTIs.
Describe the various routes in which bacteria enter the urinary tract and cause infection.
Discuss how host defense mechanisms and bacterial virulence factors play a role in the development of UTIs.
Describe the clinical presentation of lower and upper UTIs.
Evaluate the various laboratory tests utilized in the diagnosis ...