Urine

The most common sites of urinary tract infection (UTI): bladder (cystitis) urethra Females are more prone to infection In both males and females, UTI may be Asymptomatic Acute Chronic Escherichia coli being isolated far more frequently than any other organism Two organisms may be present (10% of patients with UTI) The presence of three or more different organisms in a urine culture is strong presumptive evidence of improper collection or handling of the urine specimen Multiple organisms are often seen in UTI in patients with indwelling bladder catheters.

Specimen collection sterile, wide-mouthed, glass or plastic jars, beakers, or other suitable receptacles tight-fitting,lids or be covered with aluminium foil prior to sterilization by dry heat or autoclaving Urine specimens: suprapubic aspiration Cystoscopy Catheterization clean-catch midstream

Specimen collection processed by the laboratory within 2 hours of collection, or be kept refrigerated at 4◦C until delivery to the laboratory and processed no longer than 18 hours after collection

Specimen collection female 1.Wash her hands thoroughly with soap and water and dry them with a clean towel. 2.Spread the labia, and cleanse the vulva and labia thoroughly using sterile cotton gauze pads and warm soapy water, wiping from front to rear. (Disinfectants should not be used.) 3.Rinse the vulva and labia thoroughly with warm water and dry with a sterile gauze pad. During the entire process the patient should keep the labia separated and should not touch the cleansed area with the fingers. 4.Pass a small amount of urine. The patient should collect most of the remaining urine in a sterile container, closing the lid as soon as the urine has been collected. 5.Hand the closed container to the nursing personnel for prompt delivery to the laboratory.

Specimen collection male 1.Wash his hands thoroughly with soap and water and dry them with a clean towel. 2.wash the glans thoroughly using sterile cotton gauze pads and warm soapy water. Disinfectants should not be used. 3.Rinse the glans thoroughly with warm water and dry with a sterile gauze pad. 4.The patient should pass most of the remaining urine into a sterile container, closing the lid as soon as the urine has been collected. 5.Hand the closed container to the nursing personnel for prompt delivery to the laboratory.

Infants and children 1. Give the child water or other liquid to drink 2. Clean the external genitalia. The child can be seated on the lap of the mother, nurse, or ward attendant, who should then encourage the child to urinate and collect as much urine as possible in a sterile container 3.The container should then be covered and delivered to the laboratory for immediate processing

Culture and interpretation 1. Examination of a Gram-stained smear. 2. A screening test for significant bacteriuria. 3. A definitive culture for urine specimens found to be positive in the screening test, and for all specimens obtained by cystoscopy, suprapubic bladder puncture (SBP), or catheterization. 4. Susceptibility tests on clinically significant bacterial isolates

Gram-stained smear : Using a sterile Pasteur pipette (one for each sample)place one drop of well-mixed, uncentrifuged urine on a slide. Allow the drop to dry without spreading, heat-fix and stain. Examine under an oil-immersion lens for the presence or absence of bacteria, polymorphonuclear leukocytes, and squamous epithelial cells Culture and interpretation

well-mixed, uncentrifuged urine 1≤ Bac/ field 10 5 ≤ Bac UTI 1≤ leukocytes/ field UTI few or no bacteria or leukocytes Non-infected

Screening method + bacteria in excess of 10 5 per ml The test strip may not be sensitive enough to detect bacterial counts of less than 10 5 per ml of urine.

Quantitative culture and presumptive identification Calibrated loop technique: Calibrated plastic or metal loop to transfer 1µl of urine to the culture medium MacConkey agar with crystal violet and non-selective blood agar 1. Shake the urine gently, then tip it to a slant and with a 1µl inoculating loop touch the surface so that the urine is sucked up into the loop. 2. Deposit 1µl of the urine on a blood agar plate and streak half the plate by making a straight line down the centre (1), followed by close passes at right angles through the original (2), and ending with oblique streaks crossing the two previous passes(3) 3. Inoculate the MacConkey agar in the same manner. 4. Incubate the plates overnight at 35◦C.

urine Category 1 ≤10 4 cfu/ml probable absenceof UTI Exception Category cfu/ml symptomatic if 1 or 2 different colony types identification & susceptibility doubt Request a 2th urine asymptomatic Request a 2th urine Category ≤ cfu/ml if 1 or 2 different colony types identification & susceptibility If ≥2 species of bacteria are present in urine samples in categories 2 and 3, report as “Probably contaminated; please submit a fresh, clean-catch specimen”