Urine is one of the most frequently specimen submitted for culture in microbiology. Therefore the urine collection, transport, culture techniques, and interpretation of results is very important in order to obtain accurate and reliable result. As with any other specimen submitted to the laboratory, the more comprehensive the information provided by the submitting physician the more able the laboratory will provide reliable culture data.
The most common sites of urinary tract infection (UTI) are the urethra and urinary bladder (cystitis). From these sites, the infection may ascend into the ureters causing urethritis and subsequently involving the kidney(pyelonephritis).
There is no obvious doubt that females are more prone to Urinary tract infections than are males and they also present the greater problem proper collection of urine specimens.
Stage of urinary tract infections in both males and females, may start from asymptomatic, acute, to chronic.Asymptomatic infection can be diagnosed by culturing the urine specimen. As for acute UTI,it is more frequently seen in females of all ages; these patients are usually treated on an outpatient basis and are rarely admitted to hospital.
A Chronic urinary tract infection in both males and females is usually associated with an underlying disease such as pyelonephritis, prostatic disease, or congenital anomaly of the genitourinary tract) and these often result to hospitalization of these patients. Asymptomatic,acute, and chronic urinary tract infection are three distinct entities and the laboratory results often require different interpretation.
In female, asymptomatic pyelonephritis may remain undetected for a long period of time, and is often only diagnosed by carefully performed quantitative urine culture. Chronic prostatitis is common and difﬁcult to cure, and is often responsible for recurring urinary tract infection. In most urinary tract infection, irrespective of type, enteric bacteria are the etiological agents such as Escherichia coli,Proteus species and sometimes even protozoans and fungi are incriminated.
In about 10% of patients with urinary tract infection, two organisms may be present and both may contribute to the disease process.The presence of three or more different organisms in a urine culture is a strong presumptive evidence of improper collection or handling of the urine specimen. However, multiple organisms are often seen in urinary tract infection in patients with indwelling bladder catheters.Therefore Urine specimen collection is very important for accurate result and the culture media of choice for urine culture is Cysteine Lactose Electrolyte deficient Agar abbreviated CLED Agar while the best urine specimen for urine culture is the early morning mid stream urine as explain below
Urine specimen collection
The importance of the method of collection of urine specimens, their transport to the laboratory, and the initial efforts by the laboratory to screen and culture the urine cannot be overemphasized.
ideal urine container
should be sterile
- wide-mouthed, glass or plastic jars, beakers, or other suitable receptacles.
- It should have tight-ﬁttinglids or be covered with aluminium foil prior to sterilization by dry heat or autoclaving.
Urine specimens may have to be collected by a surgical procedure, like
- the supra-pubic aspiration
If not, the laboratory must insist on a clean-catch midstream urine specimen, particularly in females and children. Since urine itself is a good culture medium, therefore ,all urine specimens should be 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.
Whenever possible, urine specimens for culture should be collected in the morning. It is advisable to ask the patient the night before to refrain from urinating until the specimen is to be collected.
How to Collect Urine specimen from Female (Midstream Urine)
- Wash her hands thoroughly with soap and water and dry them with a clean towel.
- Spread the labia, and cleanse the vulva and labia thoroughly using sterile cotton gauze pads and warm soapy water, wiping from front to rear. Don’t use disinfectant to clean the vulva
- 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.
- Now pass a small amount of urine (Midstream).This help to clear out any possible bacteria or particle found at the mouth of the urethra
- The patient should collect most of the remaining urine in a sterile container, closing the lid as soon as the urine has been collected. This is a midstream urine specimen.
- Hand the closed container to the nursing personnel for prompt delivery to the laboratory or directly to the laboratory
How to Collect Urine specimen from Male
- Wash his hands thoroughly with soap and water and dry them with a clean towel
- Pull back the foreskin (if not circumcised) and wash the glans thoroughly using sterile cotton gauze pads and warm soapy water.Disinfectants should not be used for this process.
- Rinse the glans thoroughly with warm water and dry with a sterile gauze pad.
- During the entire procedure the patient should not touch the cleansed area with the ﬁngers.
- Pull back the foreskin and pass a small amount of urine. Still holding back the foreskin, the patient should pass most of the remaining urine into a sterile container, closing the lid as soon as the urine has been collected.This is also a midstream urine specimen.
- Hand the closed container to the to the laboratory.
For bedridden patients, the same procedure is followed, except that a nurse must assist the patient or, if necessary, do the entire cleansing procedure before requesting the patient to pass urine.In both situations every effort must be made to collect a clean-catch urine specimen in a sterile container and to ensure that it is delivered promptly to the laboratory together with information on the patient, the clinical diagnosis, and the requested procedures.
Infants and children
Collection of a clean-catch urine specimen from infants and children who are ill in bed or uncooperative can be a serious problem.
- Start by giving the child water or other liquid to drink.
- 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.
- The container should then be covered and delivered to the laboratory for immediate processing.