Disease
Urinary tract infection
Lower or upper urinary infection syndrome
High-yield clue
Dysuria and urinary frequency with pyuria and a positive nitrite/leukocyte-esterase urinalysis is the classic cystitis clue.
Overview
Infection of the bladder (cystitis) or kidney (pyelonephritis), studied for its enteric Gram-negative organisms and classic urinalysis findings. It matters as one of the most common bacterial infections, especially in women, and a frequent lab-interpretation scenario.
Classification
- Genitourinary syndrome
- Cystitis (lower) vs pyelonephritis (upper)
- Uncomplicated vs complicated framing
- Community vs catheter-associated contrast
Lab & identification clues
- Pyuria with positive nitrites and leukocyte esterase vocabulary
- Urine culture colony-count concept
- Flank pain and fever suggesting upper-tract involvement
- Struvite stone association with urease-positive organisms
Associations
- Ascending fecal-flora route; E. coli most common
- At-risk framing: female anatomy, catheters, pregnancy
- Staphylococcus saprophyticus in young sexually active women
- Catheter-associated infection as a healthcare-associated issue
Commonly confused with
- Vaginitis / urethritis
- Asymptomatic bacteriuria
Your notes
Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.