From the Guidelines
A positive urinary tract infection (UTI) finding with elevated white blood cells (WBC) in the urine indicates an active infection, and treatment should be guided by the presence of pyuria, typically showing more than 5-10 WBCs per high-power field on urinalysis, as suggested by the study 1.
Diagnosis and Treatment
The presence of WBCs in the urine occurs because the immune system sends these cells to fight the bacterial invasion in the urinary tract. Other common UTI symptoms include painful urination, frequency, urgency, and sometimes blood in the urine.
- The study 1 found that the relative risk of an ambiguous culture result for specimens obtained by bag was 2.7, and the absolute risk was small, suggesting that a positive bagged urinalysis result should prompt a urine culture obtained by catheterization or suprapubic aspiration.
- A Class II meta-analysis of diagnostic tests for urinary tract infection evaluated 95 studies in 95,703 children aged 18 years or younger, and found that urine WBC counts (>10/mL) had a sensitivity of 74% and a specificity of 86% 1.
Management
Treatment usually involves antibiotics such as nitrofurantoin (Macrobid) 100mg twice daily for 5 days, trimethoprim-sulfamethoxazole (Bactrim) DS twice daily for 3 days, or fosfomycin (Monurol) as a single 3g dose.
- While waiting for treatment, drinking plenty of water can help flush bacteria from the system, as suggested by the study 1.
- The presence of fever, back pain, or nausea could indicate a more serious kidney infection requiring immediate medical attention, and completion of the full course of antibiotics is necessary even if symptoms improve before finishing, as recommended by the study 1.
Key Considerations
- A negative urinalysis result from a bagged specimen may be useful for clinical decision-making, but a positive bagged urinalysis result should prompt a urine culture obtained by catheterization or suprapubic aspiration, as suggested by the study 1.
- The minimum laboratory evaluation for suspected UTI should include urinalysis for determination of leukocyte esterase and nitrite level by use of a dipstick and a microscopic examination for WBCs, as recommended by the study 1.
From the Research
Positive UTI Findings and WBC
- The presence of white blood cells (WBC) in urine is a common indicator of a urinary tract infection (UTI) 2, 3.
- Studies have shown that nitrofurantoin is an effective treatment for uncomplicated UTIs, with a high susceptibility rate against common UTI pathogens such as Escherichia coli 2, 4.
- The use of nitrofurantoin has increased in recent years, and it is now considered a first-line treatment for uncomplicated UTIs due to its low resistance rate and effectiveness 4, 5.
- Other antibiotics, such as trimethoprim-sulfamethoxazole and fluoroquinolones, may also be used to treat UTIs, but their use is often limited due to high resistance rates and potential side effects 3, 5.
- A systematic review of randomized control trials found that nitrofurantoin is at least comparable to other UTI treatments in terms of efficacy, with clinical cure rates ranging from 51 to 94% and bacteriological cure rates ranging from 61 to 92% 6.
Treatment Options
- Nitrofurantoin is a commonly used antibiotic for treating UTIs, with a low resistance rate and high effectiveness 2, 4.
- Trimethoprim-sulfamethoxazole is another antibiotic that may be used to treat UTIs, but its use is often limited due to high resistance rates 3, 5.
- Fluoroquinolones may also be used to treat UTIs, but their use is often discouraged due to high resistance rates and potential side effects 5.
- Fosfomycin is another antibiotic that may be used to treat UTIs, with a high efficacy rate and low resistance rate 5, 6.
Guidelines and Recommendations
- The Infectious Diseases Society of America recommends nitrofurantoin, trimethoprim-sulfamethoxazole, and fosfomycin as first-line antibiotic treatments for uncomplicated UTIs 5.
- The use of fluoroquinolones is often discouraged due to high resistance rates and potential side effects 5.
- Guideline concordance for UTI treatment has improved in recent years, but there is still a need for increased awareness and education among physicians about antibiotic resistance and clinical practice guidelines 5.