Bacteria in Urine (Urine Bacteria): What Your Result Means
What bacteria on a urinalysis mean, why they often come from contamination, why bacteria without symptoms usually need no treatment, and when a urine culture is the next step.
- Published
- August 10, 2024
- Last updated
- November 2, 2026
- Read time
- 3 min read
- Medically reviewed by
-
Rhonda Collins, FNP-C
Bacteria seen on a urinalysis can come from a urinary tract infection (UTI) or from contamination of the sample, and the microscopic exam cannot tell the two apart on its own [1]. Bacteria in urine without symptoms, called asymptomatic bacteriuria, usually needs no treatment. Pregnancy is the main exception [1][2].
What does urine bacteria on a urinalysis mean?
The microscopic exam of a urinalysis reports whether bacteria are seen in the urine sample [3]. Bacteria are hard to see unless there are many of them. About five bacteria per high-power microscope field suggests a urine culture would grow around 100,000 bacteria per mL, the classic cutoff for a significant count [1][4].
Seeing bacteria does not identify which organism it is, or whether it is causing an infection. A urine culture is needed to find a dominant bacterial species [1].
Why can bacteria show up without an infection?
Two common reasons:
- Contamination. Clean-catch samples from women are often contaminated by bacteria from the vagina [4]. The clean-catch collection method is used to keep germs from the penis or vagina out of the sample [5].
- Asymptomatic bacteriuria. Bacteria can live in the bladder without causing an infection. This is common in many people, including healthy women [2].
Does bacteria in urine without symptoms need treatment?
Usually not. The Infectious Diseases Society of America (IDSA) guideline on asymptomatic bacteriuria advises screening for and treating it only during pregnancy or before an invasive urologic procedure [2]. It does not recommend treatment for healthy women, older women or men, or people with diabetes, indwelling catheters, or spinal cord injury [2]. Treating bacteria that cause no symptoms adds to unnecessary antibiotic use, which drives antibiotic resistance [2]. Asymptomatic bacteriuria is often treated unnecessarily in older adults [1].
If you are pregnant, raise any bacteria on a urinalysis with your prenatal care team, since pregnancy is when bacteria without symptoms is screened for and treated [1][2].
When does urine bacteria point to a urinary tract infection?
Bacteria are more likely to mean an infection when you have symptoms or when other urinalysis results also suggest one. UTI symptoms include pain or burning when you urinate, a strong need to urinate often, pressure in the lower abdomen, and cloudy or strong-smelling urine [6]. A urine culture is recommended when UTI symptoms are present [1]. In a properly collected sample from a man, bacteria suggest infection and a culture should be done [4].
Bacteria are read together with urine nitrite, urine leukocytes (leukocyte esterase), and the urine white blood cell count. For how these results combine into an infection reading, see our guide to nitrites in urine.
Urine bacteria testing with Mito
The Urinalysis, Complete Test with Reflex to Urine Culture reports bacteria on its microscopic exam and runs a urine culture automatically if the urinalysis shows signs of a possible infection. To identify the organism directly, the Urine Culture, Routine Test grows and identifies the bacteria in a sample. Check each product page for current pricing and availability.
Related Urine Bacteria Resources
References
- Hitzeman N, Greer D, Carpio E. Office-Based Urinalysis: A Comprehensive Review. Am Fam Physician. 2022
- Nicolle LE, Gupta K, Bradley SF, et al. Clinical Practice Guideline for the Management of Asymptomatic Bacteriuria: 2019 Update by the Infectious Diseases Society of America. Clin Infect Dis. 2019
- MedlinePlus Medical Encyclopedia: Urinalysis
- Simerville JA, Maxted WC, Pahira JJ. Urinalysis: A Comprehensive Review. Am Fam Physician. 2005
- MedlinePlus Medical Encyclopedia: Clean catch urine sample
- MedlinePlus Medical Encyclopedia: Urinary tract infection, adults
Kidney and urinary health tests
Cystatin C with Estimated Glomerular Filtration Rate (eGFR) Blood Test
A kidney filtration marker that stays accurate when muscle mass throws off creatinine.
Comprehensive Metabolic Panel (CMP)
A 14-marker snapshot of kidney function, liver function, electrolytes, and blood sugar in one draw.
