Bacteriuria

Introduction True bacterial urine means: 1 bladder puncture urine culture, bacterial growth, or colony number > 102 / ml. 2 urinary bacteria quantitative culture 105 / ml. 3 The middle-stage urine quantitative culture was 105/ml, and the accuracy was 80%. The same strain was obtained by two consecutive cultures, the number of colonies was 105/ml, and the accuracy was 95%.

Cause

Clinically, as long as there is true bacterial urine, it can be diagnosed as a urinary tract infection. The common causes are as follows:

1, ascending infection: its pathogen is from the urethra through the bladder, ureter and up to the kidneys. Under normal circumstances, a small amount of bacteria is present at the upper end of the urethral opening 1 to 2 cm. Only when the body's resistance is reduced or the urethral mucosa is damaged, the bacteria can invade and multiply. Urine flushing, IgA in urine, lysozyme, organic acids, mucosal integrity, and mucosin secreted by the bladder transitional epithelium can resist the invasion of pathogens.

2, bloodline infection: bloodline infections account for only 3% of urinary tract infections. The blood flow of the kidney accounts for 20% to 25% of the cardiac output. When sepsis and bacteremia occur, the bacteria in the circulating blood easily reach the renal cortex. Diabetes, polycystic kidney disease, transplanted kidney, urinary tract obstruction, renal vascular stenosis, analgesics or the use of sulfonamides increase the vulnerability of kidney tissue. Common pathogens such as Staphylococcus aureus, Salmonella, Pseudomonas, and Candida albicans are rare, and lymphatic infection has not been confirmed.

an examination

Related inspection

Urine bacterial culture urine routine urine protein quantification

Laboratory inspection

1, urine routine examination

Urine routine examination is the easiest and most reliable way to diagnose urinary tract infections. It is advisable to leave the first urine in the morning for testing. More than 5 (5/HP) white blood cells per high power field are called pyuria. In addition to pyuria in acute urinary tract infections, white blood cell casts, bacteriuria, and sometimes hematuria or gross hematuria can be found, especially when infected with Brucella, Nocardia, actinomycetes, and Mycobacterium tuberculosis. Occasionally, microalbuminuria, if more proteinuria, suggests glomerular involvement.

2, urine bacterial culture

In the past, it was considered that the cleaned mid-stage urine culture colony count of 100,000/ml had clinical significance, and 10,000/ml was caused by pollution. A large number of facts have been proved that although about 92% of Gram-negative bacteria cause urinary tract infection colony counts of 100,000/ml, only about 70% of Gram-positive bacteria cause urinary tract infections with counts of more than 100,000/ml. The other 20% to 30% of patients have a colony count of only 1,000 to 100,000 / ml, especially in most patients with lower urinary tract infection. The reasons for the low colony count are:

(1) Urinary urgency and other irritating symptoms make the urine stay in the bladder for too short time, which is not conducive to the reproduction of bacteria.

(2) It has been treated with antibiotics.

(3) The application of diuretics makes the bacteria difficult to grow and reproduce.

(4) Acidified urine is not conducive to bacterial growth and reproduction.

(5) There is urinary tract obstruction (such as stones and infection), and bacteriuria excretion is restricted.

(6) Extraluminal infection.

(7) The pathogen is an anaerobic bacterium and cannot be cultured in a conventional medium.

(8) Gram-positive bacteria have a slow division and a tendency to agglutinate, and colony counts tend to be low.

Differential diagnosis

Asymptomatic bacteriuria: also known as occult bacteriuria, is a occult urinary tract infection, which means that the patient has true bacterial urine (quantitative culture of urinary bacteria in the middle of cleaning is more than 105/ml for 2 consecutive times, and the same 2 strains are the same And the false positives of the results were excluded without any symptoms of urinary tract infection, but in some cases, mild symptoms were found after careful inquiry. Its bacteria come from the kidneys or from the bladder. Asymptomatic bacterial urine has a higher incidence than symptomatic patients. The incidence rate is 4% in women aged 16 to 65 and 0.5% in men. Although 1/4 of bacteriuria disappears in female patients, New bacterial urine is also constantly occurring, so the incidence of 4% is quite constant.

Bacterial urinary: Normally, the urine is sterile, but the lower third of the urethra and the urethra are bacteriological. Therefore, urine discharged from the human body can contaminate the upper part of the bacteria. However, the amount of bacteria in the middle of the cleansing should not exceed 105/ml. If the test contains more than or equal to 105/ml of bacteria and is the same strain, and there is no urinary tract infection (frequent urination, urgency or lower abdominal discomfort), it can be diagnosed as true bacteriuria, also known as no Symptomatic bacteriuria.

Renal glucosuria: refers to a disease of diabetes caused by a decrease in glucose function in the proximal tubules when the blood glucose concentration is normal or lower than the normal renal sugar threshold. Clinically divided into primary renal glucosuria and secondary renal glucosuria. White blood cell urine: refers to freshly centrifuged urine. There are more than 5 white blood cells per high power microscope field, or more than 400,000 white urine cells per hour or more than 1 million urine in 12 hours.

Hyperoxaluria: Primary hyperoxaluria is a rare hereditary disease. There are two clinical types, type I and type II hyperoxaluria, which are autosomal recessive. There was no significant difference in clinical manifestations between the two types. The ratio of male to female incidence was about 1.3:1, and about 12% of patients developed symptoms before the age of one. 65% were ill before the age of 5. The main manifestations of this disease are kidney stones, renal calcium deposition and extrarenal calcium deposition.

The patient has recurrent renal colic and hematuria, often with pyelonephritis and hydronephrosis. Extrarenal tissue calcium deposits occur mostly in the heart, male reproductive organs and bones. Calcium oxalate crystals can settle on the vessel wall. The disease progresses rapidly, and uremia gradually develops. At this time, secondary hyperparathyroidism can be combined. Infants who died in infants died before the age of 20, and the prognosis of adult patients was relatively good.

1 bladder puncture urine culture, bacterial growth, or colony number > 102 / ml.

2 urinary bacteria quantitative culture 105 / ml.

3 clean middle-stage urine quantitative culture 105/ml, one time accuracy 80%; the same strain was obtained twice in two consecutive cultures, the number of colonies was 105/ml, the accuracy was 95%; if the number of colonies of medium-sized broth was 104-105/ Between ml, listed as suspicious, should be repeated culture; if it is cocci, the number of colonies in the middle urine culture is 200/ml, which is diagnostic.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.