| Bacteriuria | |
|---|---|
| Classification and external resources | |
Multiple rod-shaped bacteria shown between the larger white blood cells at urinary microscopy from a patient with urinary tract infection. |
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| MedlinePlus | 000520 |
In medicine, bacteriuria denotes the presence of bacteria in urine not due to contamination from urine sample collection.
Urine is normally a sterile bodily fluid when inside the bladder, but can pick up commensals and pathogens when exiting through the urethra. Bacteria in the urine, especially gram-negative rods, usually indicate a urinary tract infection (either cystitis or pyelonephritis), although bacteriuria can also occur in prostatitis. Escherichia coli is the most common bacterium isolated from urine samples.
Asymptomatic bacteriuria is bacteriuria without accompanying symptoms of a urinary tract infection (such as frequent urination, painful urination or fever). It is more common in women, in the elderly, in residents of long-term care facilities, and in patients with diabetes, bladder catheters and spinal cord injuries. Patients with a long-term Foley catheter uniformly show bacteriuria.
Contents |
| Group | Prevalence (in %) | |
|---|---|---|
| Healthy premenopausal women | 1.0 to 5.0 | |
| Pregnant women | 1.9 to 9.5 | |
| Postmenopausal women (50 to 70 years of age) | 2.8 to 8.6 | |
| Patients with diabetes mellitus | Women | 9.0 to 27.0 |
| Men | 0.7 to 1.0 | |
| Older community-dwelling patients | Women (older than 70 years) |
> 15.0 |
| Men | 3.6 to 19.0 | |
| Older long-term care residents | Women | 25.0 to 50.0 |
| Men | 15.0 to 40.0 | |
| Patients with spinal cord injury | Intermittent catheter | 23.0 to 89.0 |
| Sphincterotomy and condom catheter |
57.0 | |
| Patients undergoing hemodialysis | 28.0 | |
| Patients with an indwelling catheter | Short-term | 9.0 to 23.0 |
| Long-term | 100 | |
Bacteria can be detected with a urine dipstick test for urinary nitrite or by urinary microscopy, although bacterial culture remains the most specific and formal test (the golden standard). Bacteriuria can be confirmed if a single bacterial species is isolated in a concentration greater than 100,000 colony forming units per millilitre of urine in clean-catch midstream urine specimens (one for men, two consecutive specimens with the same bacterium for women). For urine collected via bladder catheterisation, the threshold is 100 colony forming units of a single species per millilitre.
The presence of simultaneous pyuria does not warrant treatment by itself.
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