bacteriuria

Bacteriuria is the presence of bacteria in urine. It is commonly divided into asymptomatic bacteriuria, where bacteria are detectable without urinary symptoms, and symptomatic bacteriuria, typically referred to as a urinary tract infection (UTI), with symptoms such as dysuria, frequency, urgency, or suprapubic pain.

The condition is most often due to ascending infection from the periurethral area. The most frequent organism is Escherichia coli; other common pathogens include Staphylococcus saprophyticus, Klebsiella, Proteus, Enterococcus, and Pseudomonas species. Risk factors include female sex, urinary catheterization, sexual activity, diabetes, and urinary tract abnormalities.

Diagnosis relies on proper urine collection and laboratory testing. A clean-catch midstream or catheterized urine sample is preferred. Significant bacteriuria has traditionally been defined as about 10^5 colony-forming units per milliliter in voided specimens, though symptomatic infections can occur at lower counts. Urinalysis showing pyuria and nitrite positivity supports infection but is not definitive; results must be interpreted in context.

Asymptomatic bacteriuria generally does not require treatment in nonpregnant adults, to avoid unnecessary antibiotic use. Treatment is recommended for pregnant women and in certain high-risk scenarios (e.g., before some urologic procedures or in selected immunocompromised patients).

Symptomatic bacteriuria is treated with an appropriate antibiotic guided by local resistance patterns. Common options include nitrofurantoin, trimethoprim-sulfamethoxazole, fosfomycin, or amoxicillin-clavulanate, typically for a short course for uncomplicated cases and longer therapy for complicated infections or pyelonephritis. In elderly or catheter-associated cases, management focuses on symptoms and risk of progression.

Complications can include progression to pyelonephritis, bacteremia, or sepsis, especially in pregnancy, the elderly, and immunocompromised individuals. Preventive measures emphasize prudent antibiotic use and proper catheter care.