Generality
The presence of numerous bacteria in the urine (bacteriuria) is a condition that represents a probable sign of urinary infections in progress.
Bacteriuria can be associated with the typical symptoms of cystitis (urgent need to urinate, fever, pain in the lower abdomen etc.) or be asymptomatic, that is not connected to any kind of discomfort.
The bacterium identified in the urine most frequently is Escherichia coli .
What's this
Bacteriuria is the presence of significant amounts of bacteria in the urine (over 100, 000 per milliliter). Given that the urine is normally sterile, the finding of this finding is a probable indicator of urinary tract infections (UTIs), acute or chronic.
The infection can come from other organs: in women, for example, from the vagina or from the anal area, in men from the prostate (in the presence of a concomitant prostatitis).
Why do you measure
Bacteria can be detected in urine, during sediment examination or by urine culture, if an urinary tract infection (urethra, urinary bladder, renal pelvis or kidney) or genital tract is in place.
The microscopic observation of bacteria in the urinary sediment can offer indications on the identity of the pathogens in question. Their exact identification is obtained, however, by seeding the infected urine on special culture media (urine culture).
Important for prognostic and therapeutic purposes is the determination of the bacterial charge, which is obtained by counting, ie determining the number of germs present in a given volume of urine.
Possible symptoms
The symptoms associated with a high level of bacteria in the urine can be non-specific and common to a large number of disorders and / or diseases. In general, however, bacteriuria may be related to typical manifestations of urinary infections such as:
- Sense of general malaise;
- Repeated urge to urinate;
- Feeling of not having completely emptied the bladder;
- Pain or discomfort during urination;
- Turbid and foul-smelling urine;
- Pain in the lower part of the abdomen.
When the exam is requested
The test to assess the presence of bacteria in urine is required when a urinary tract infection is suspected of causing discomfort and pain during urination, frequent urination or all the other symptoms mentioned above.
Normal values
Urine is normally a sterile biological fluid or, at least, with a low bacterial load; therefore the urine culture must give a negative result.
- Normal values : less than 100, 000 CFU (Colony Forming Units, ie bacteria) per milliliter.
A urine culture in which there are 10, 000 to 100, 000 CFU / ml is considered doubtful, while the test is positive when there are more than 100, 000 CFU / ml.
In people with a catheter, any charge is considered noteworthy, as this device facilitates the entry of bacteria and the onset of infections. Even if bacterial agents are found in urine taken from the bladder (percutaneously via a sterile needle), the sample with a lower bacterial concentration is also considered positive.
This finding indicates that there is inflammation sustained by bacteria along the urinary tract, or, more rarely, pathogens from the blood are eliminated through the kidney.
High bacteriuria - Causes
In most cases, high bacteriuria indicates the presence of an infection and / or inflammation of the urinary tract or genital tract.
More specifically, high bacteria values can be associated with:
- Cystitis (very annoying inflammation that affects the bladder mucosa);
- Acute or chronic urethritis (inflammation of the urethra);
- Prostatitis (inflammation of the prostate gland);
- Instrumental and surgical operations (eg transurethral bladder catheter);
- Pregnancy and puerperium.
The bacteria most commonly found in urine are:
- Neisseria gonorhoeae : bacterial agent responsible for gonorrhea, sexually transmitted disease.
- Pseudomonas aeruginosa : bacterium based on pathological conditions, such as cystitis and urethritis.
- Escherichia coli : bacterial agent involved in most cystitis.
- Proteus : bacterium also responsible for urinary tract infections.
- Staphylococcus : bacterial agent involved in various urogenital infections.
Possible complications
Untreated with antibiotics, bacteriuria is associated with an increased risk of pyelonephritis. In this condition, the bacteria contained in the urine are more likely to rise to the kidneys and cause inflammation, compromising its functionality.
Low bacteriuria - Causes
Normally, there are no bacteria either in the kidneys or in the bladder, while some germs can contaminate the urine when they pass into the urethra.
How to measure it
The presence of bacteria in the urine is detected by their research by urine culture . This analysis is prescribed when white blood cells are found in the urine and the doctor has reason to think that there is a bacterial infection in the urinary tract, such as, for example, cystitis. If the culture is positive, an antibiogram is performed to guide the doctor in the choice of antibiotic therapy.
Bacteria in the sample can also be highlighted with the microscope observation of a few drops of urine after centrifugation ( urinary sediment ).
Preparation
Urine culture should be performed on two successive urine samples. In order to carry out this examination, it is necessary to interrupt treatment with antibiotics at least seven days before. The urine must be collected in the morning after washing your hands and having practiced a thorough local intimate hygiene, eliminating the first jet and using a sterile container.
The sample thus collected must be delivered to the laboratory within one hour or stored in the refrigerator for up to 12 hours.
Interpretation of Results
The results of the culture examination must be evaluated, together with the results of the complete urine analysis, by the general practitioner, who knows the history of his patient. Since some urinary specimens can be potentially contaminated by the normal bacterial flora of the skin, much attention must be paid in the interpretation of the examination.
If numerous bacteria are found in the urine, the doctor will prescribe an antibiotic therapy, active against the type of bacterium identified as being responsible for the infection, and will schedule subsequent checks to verify the efficacy of the drugs taken.
