Bacteriuria - Sampling methods and significance

Bacteriuria is defined as the presence of any number of bacteria in the bladder urine that is uncontaminated by urethral or vaginal organisms, a term synonymous with urinary tract infection (UTI). We agree that proper urine collection techniques are critical for the diagnosis of UTI. What is usually mentioned in most investigative trials is that "a midstream clean-catch urine specimen is collected" without describing the technique of such a collection, but we understand that the midstream urine (MSU) specimen is collected by the patient herself. In 42.6% of the 54 women with sterile urine, the "clean-catch midstream urine specimens," collected by the patient herself, grew between 1,000 and > 100,000 cfu/ml; only 1.9% of these women voided a sterile urine specimen. Twenty-six out of 54 urine cultures grew gram-negative bacilli. However, if the midstream urine was collected by a trained nurse from the patient after adequate preparation in a semi-sitting position on a cystoscopy table with her legs separated in stirrups, the quality of the midstream urine specimens changed dramatically. All the clean-catch midstream urine specimens in the 151 women with sterile urine grew less than 1,000 cfu/ml; 36% of these women voided a sterile urine specimen and 39% voided a urine specimen with less than 100 cfu/ml.