Proteus

Snapshot

A 24-year-old woman at 8 weeks of gestation presents to her obstetrician for increased urinary frequency, dysuria, and some suprapubic pressure for the past few days. She has a history of spontaneous abortions. On physical exam, she has suprapubic tenderness to palpation and right costovertebral tenderness. A rapid urine dipstick shows nitrite, leukocyte esterase, and urease positivity. She is started on an antibiotic that is safe for pregnant women.

Introduction

Classification
- Proteus spp.
  - P. mirabilis (most common, both community-acquired and nosocomial)
  - P. vulgaris (nosocomial)
  - urease-positive, oxidase-negative, and non-lactose fermenting gram-negative bacillus
- causes urinary tract infections (UTI)
Epidemiology
- incidence
  - very common
- demographics
  - women > men
- risk factors
  - urinary catheter
  - urinary tract obstruction
  - living in nursing home
  - hospital admission
  - immunocompromised status
Pathogenesis
- increased inoculum size is correlated with risk of infection
- the bacteria attach to the urinary tract endothelium
- can produce endotoxin that can lead to sepsis
- hydrolyzes urea to ammonia, which alkalinizes the urine
Associated conditions
- struvite kidney stones
Prognosis
mortality is low with treatment

Presentation

Imaging

Abdominal computed tomography (CT)
- indication
  - evaluate for kidney stones
- findings
radiopaque stones

Studies

Urine culture
- “swarming” motility on agar plate
Urine dipstick
- leukocyte esterase positive
- nitrite positive
- urease positive
- pH alkaline
Making the diagnosis
based on clinical presentation and laboratory studies

Differential

Treatment

Complications