Urine Culture Contamination and Bacteriuria

What is considered significant bacteriuria for a complicated UTI in adults using a midstream urine sample?

Which urine culture result indicates significant bacteriuria without symptoms in adults?

For children aged 2-24 months, what is the minimum CFU/ml that indicates significant bacteriuria when pyuria is present?

What is the CFU/ml threshold for significant bacteriuria in women with recurrent UTIs using a midstream urine sample?

In patients with upper UTIs and symptoms, what is the minimum CFU/ml required for significant bacteriuria?

What is the threshold for significant bacteriuria in catheter-collected urine for adults with UTI symptoms?

Urine Culture Contamination Thresholds

Non-invasive specimen collection (e.g., midstream urine): Contamination is considered when colony-forming units (CFU) are less than 10³ per milliliter (mL).
Invasive specimen collection (e.g., catheterization): Contamination is considered when CFU are less than 10² per mL.

Significant Bacteriuria (Adults) - Midstream Urine

Complicated UTI: Significant bacteriuria is indicated by a count of 10⁵ CFU/mL or greater.
Recurrent UTI (women): Significant bacteriuria is indicated by a count of 10⁵ CFU/mL or greater.
Upper UTI with symptoms (no complications): Significant bacteriuria is indicated by a count of 10⁴ CFU/mL or greater.
Lower UTI with symptoms (men and women): Significant bacteriuria is indicated by a count of 10³ CFU/mL or greater.

Significant Bacteriuria (Adults) - Catheter-Collected Urine

UTI with symptoms: Significant bacteriuria is indicated by a count of 10³ CFU/mL or greater.
UTI without symptoms: Significant bacteriuria is indicated by a count of 10⁵ CFU/mL or greater.

Significant Bacteriuria (Children)

Catheter or suprapubic bladder puncture: Significant bacteriuria is indicated by a count of 5 x 10⁴ CFU/mL or greater.
Catheter or suprapubic bladder puncture AND pyuria (pus in urine) in children 2-24 months old: Significant bacteriuria is indicated by a count of 5 x 10⁴ CFU/mL or greater.
Midstream sample AND symptoms of UTI: Significant bacteriuria is indicated by a count of 10⁵ CFU/mL or greater.

This quiz focuses on the thresholds for urine culture contamination and significant bacteriuria in adults. It covers both non-invasive and invasive specimen collection methods, as well as the criteria for diagnosing complicated and recurrent urinary tract infections. Test your understanding of these important microbiological concepts.