Urine Culture, Comprehensive

Urine

To minimum fill line (4 mL) on Vacutainer® gray-top urine culture transport tube with preservative (preferred)

Vacutainer® gray-top urine culture transport tube with preservative (preferred). If less than 4 mL of urine is collected, usually from pediatric and geriatric patients or from a catheter, submit refrigerated in a sterile, screw cap container or tube. Do not submit low volume urine specimens in underfilled gray top tubes.

Patient should be instructed on the proper collection of a clean catch midstream urine specimen. Avoid contamination with normal flora from skin, rectum or vagina. If a clean catch urine cannot be obtained from an infant, obtain a bagged specimen: clean area as for a clean catch, attach U-bag, and put collected urine into a sterile container.

Clean catch specimen: Have patient urinate into a small clean disposable cup (styrofoam or “Dixie”). Afterward, collection site staff can transfer the urine to the urine culture transport tube using the special collection straw-puncture device designed for use with the Vacutainer® tubes. The numbers of bacteria in a clean unused cup are so few as to be inconsequential when the urine transport stabilizer is added. Thoroughly instruct patient for proper collection of a “clean catch” specimen. Patient must be instructed to thoroughly cleanse skin and collect a midstream specimen. The patient should be instructed to follow the directions provided with the urine collection kit as follows.

Catheterized specimen: Refers to an “in and out” catheter that is placed into the bladder solely for collection of the specimen and then withdrawn. Do not collect urine from the drainage bag when an indwelling catheter is in place because growth of bacteria can occur in the bag itself. Rather, clean catheter with an alcohol sponge, puncture with a sterile needle, and collect in sterile syringe. Catheter tips are contaminated by the urethra as they are withdrawn; do not culture them.

Male: Wash hands thoroughly with soap and water. Rinse them well and dry with a paper towel.

• Tear open the towelette packages so that the towels can be easily removed with one hand as they are needed. Do not touch any of the inside surfaces of the collection cup.

• Pull back the foreskin to expose the head of the penis completely.

• Wash the head of the penis thoroughly using first one towelette then the other. Discard the used towelettes into the toilet bowl.

• Pass a small amount of urine into the toilet bowl, then pass a sample into the container. Do not allow the container to touch the legs or penis. Keep fingers away from the rim and inner surface of the container. Fill the container half full.

• The urine specimen should be transferred to the Vacutainer® tube within 10 minutes of collection.

Female: Wash hands thoroughly with soap and water. Rinse them well and dry with a paper towel.

• Tear open the towelette packages so that the towels can be easily removed with one hand as they are needed. Do not touch any of the inside surfaces of the collection cup.

• Remove undergarments and sit on the toilet seat with legs spread widely apart.

• With one hand, spread labia apart to expose the vulva. Keep this hand in place during the washing and urinating procedure.

• Use one towelette to wash the vulva well passing the towelette only from front to back, not back and forth. Repeat this procedure using the second towelette. Discard the used towelettes into the toilet bowl.

• Begin urinating into the toilet bowl then, without stopping the stream, insert the collection cup to collect the specimen. Do not allow the container to touch the legs, vulva, or clothing. Keep fingers away from the rim and inner surface of the container. Fill the container about half full.

• The urine specimen should be transferred to the Vacutainer® tube within 10 minutes of collection.

Semiquantitative culture to isolate and identify bacterial causes of urinary tract infection. Isolate and identify bacteria present in low numbers in the urinary tract. Detect up to three pathogenic bacterial organisms at levels down to 100 cfu/mL.

Culture

A single culture is about 80% accurate in the female; two containing the same organism with count of 100,000 cfu/mL or more represent a 95% chance of true bacteriuria; three such specimens mean virtual certainty of true bacteriuria. A single clean voided specimen from an adult male may be considered diagnostic with proper preparation and care in specimen collection. If the patient is receiving antimicrobial therapy at the time the specimen is collected, any level of bacteriuria may be significant. When more than two organisms are recovered, the likelihood of contamination is high; thus, the significance of definitive identification of the organisms and susceptibility testing in this situation is severely limited. A repeat culture with proper specimen collection including patient preparation is often indicated. Cultures of specimens from Foley catheters yielding multiple organisms with high colony counts usually represents colonization of the catheter and not true significant bacteriuria. Failure to recover aerobic organisms from patients with pyuria or positive Gram stains of urinary sediment may indicate the presence of mycobacteria or anaerobes. Few clinical studies have been performed to support the identification of more than two organisms or implicate usual site flora (eg, diphtheroids, α- or γ-streptococci, and coagulase-negative staphylococci other than S saprophyticus).