Bacteriuria significant

Bacteriuria, or bacteria in the urine, does not always represent infection. For this reason a number of quantitative diagnostic criteria have been created to identify the amount of bacteria in the urine that most likely represents true infection (hence the term significant bacteriuria ). These are shown in Table 76-1. Furthermore, UTIs are classified as lower tract or upper tract disease. Patients will present differently with upper versus lower tract disease, and upper tract disease is thought of as a much more severe infection, as patients are more likely to be admitted to the hospital with upper urinary tract disease than lower tract disease. An example of lower tract infection is cystitis. Cystitis refers to the syndrome associated with a UTI involving dysuria, frequency, urgency, and occasional suprapubic tenderness. An example of upper urinary tract disease is pyelonephritis. Pyelonephritis is an inflammation of the kidney usually due to infection. Frequently, patients with uncomplicated UTI are treated as outpatients, while those patients with complicated UTIs are treated as inpatients. 

It is known that an association exists between maternal UTI during pregnancy and fetal death, mental retardation, and developmental delay.24 Because of this known association, and because up to 7% of pregnant women have an asymptomatic bacteriuria that may progress to pyelonephritis, screening is necessary. In patients with significant bacteriuria, whether symptomatic or asymptomatic, treatment is recommended to avoid the complications discussed above. In the majority... 

Criteria for defining significant bacteriuria are listed in Table 50-2. 

The presence of pyuria (more than 10 white blood cells/mm3) in a symptomatic patient correlates with significant bacteriuria. 

In patients with significant bacteriuria, symptomatic or asymptomatic, treatment is recommended in order to avoid possible complications during the pregnancy. Therapy should consist of an agent with a relatively low adverse-effect potential (a sulfonamide, cephalexin, amoxicillin, amoxicillin/clavulanate, nitrofurantoin) administered for 7 days. 

Bacteriological studies usually reveal sterile urine, but in 8.3-31.8% significant bacteriuria was confirmed and considered as superimposed urinary tract infechon [88, 89]. 

Acute cystitis occurs in 0.3% to 1.3% of pregnancies. In addition to having significant amounts of bacteria in the urine, women with acute cystitis complain of urinary frequency and pain." The risks of low birth weight and preterm labor associated with acute cystitis have not been defined. Treatment for acute cystitis is the same as described for asymptomatic bacteriuria." ... 

Significant bacteriuria traditionally has been defined as bac- terial counts of greater than 100,000 (10 )/mL of urine. Many clinicians, however, have challenged this as too general a statement. Indeed, significant bacteriuria in patients... 

Asymptomatic bacteriuria is a common finding, particnlarly among those 65 years of age and older, when there is significant bacteriuria (>10 bacteria/mL of urine) in the absence of symptoms. Symptomatic abacteriuria or acute urethral syndrome consists of symptoms of frequency and dysuria in the absence of significant bacteriuria. This syndrome is commonly associated with Chlamydia infections. 

Through grade school and before puberty, the prevalence of UTI is about 1%, with 5% of females reported to have significant bacteriuria prior to leaving high school. This percentage increases dramatically to 1 % to 4% after puberty in nonpregnant females primarily as a result of sexual activity. Approximately one in five women will suffer... 

Microscopic examination of the urine for leukocytes is also used to determine the presence of pyuria. The presence of pyuria in a symptomatic patient correlates with significant bacteriuria. Pyuria is defined as a white blood cell (WBC) count of greater than 10 WBCs/mm of urine. A count of 5 to 10 WBCs/mm is accepted as the upper limit of normal. It should be emphasized that pyuria is nonspecific and signifies only the presence of inflammation and not necessarily infection. Thus patients with pyuria may or may not have infection. Sterile pyuria has long been associated with urinary tuberculosis, as well as chlamydial and fungal urinary infections. 

The diagnosis of bacterial prostatitis is made when the number of bacteria in EPS is 10 times that of the urethral sample (VBl) and midstream sample (VB2). If no EPS is available, the urine sample following massage (VB3) should contain a bacterial count 10-fold greater than that of VBl or VB2. If significant bacteriuria is present, ampiciUin, cephalexin, or nitrofurantoin should be given for 2 to 3 days to sterilize the urine prior to performing the localization study. 

The nitrite test of the Merck Co. detects as little as 10 pg H nitrite. It uses filter paper impregnated with an aqueous solution containing methanol, 1-2 g of a diazotizable amine, 0.1-0.5 g of a coupling component, and 2-8 g of solid organic acid per 100 ml. The paper is dried and cut into strips and is specific for nitrite independent of urinary pH. The test reveals significant bacteriuria when the bacterial count reaches 1 x lO ml of urine. 

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