From the Guidelines
Yes, it is possible to have a urinary tract infection (UTI) with nitrite-positive urine but without white blood cells (WBCs). This situation can occur due to various reasons such as early infections, immunocompromised patients, or bacterial colonization rather than true infection 1. The presence of nitrites in urine indicates the presence of bacteria that convert dietary nitrates to nitrites, particularly gram-negative bacteria like E. coli.
The European Association of Urology guidelines recommend urinalysis, including assessment of white and red blood cells and nitrite, for routine diagnosis of UTIs 1. However, the absence of WBCs does not necessarily rule out a UTI, especially if symptoms are present. Other possibilities include dilute urine samples, delayed testing that allowed WBCs to degrade, or infections with organisms that don't trigger significant WBC response.
Key points to consider in this scenario include:
- The patient's symptoms and medical history
- The results of the urinalysis, including the presence of nitrites
- The potential for bacterial colonization rather than true infection
- The need for clinical judgment in guiding treatment decisions rather than relying solely on the presence or absence of WBCs
In terms of treatment, antibiotics such as fluoroquinolones and cephalosporins may be recommended for oral empiric treatment of uncomplicated pyelonephritis 1. However, the choice of antibiotic and duration of treatment should be tailored to the individual patient's needs and local resistance patterns. It is essential to note that the guidelines recommend against using certain agents, such as nitrofurantoin, oral fosfomycin, and pivmecillinam, due to insufficient data regarding their efficacy 1.
From the Research
UTI Diagnosis and Treatment
- Urinary tract infections (UTIs) are typically diagnosed based on a combination of symptoms and a positive urine analysis or culture 2.
- The presence of nitrate-positive urine can indicate a UTI, as many gram-negative bacteria that cause UTIs can reduce nitrate to nitrite 3.
- However, the absence of white blood cells (WBCs) in the urine does not necessarily rule out a UTI, as some patients may not exhibit pyuria (WBCs in the urine) despite having a UTI 4.
Nitrate-Positive Urine and UTI
- Nitrofurantoin is a commonly used antibiotic for treating UTIs, particularly for uncomplicated cases 5, 6.
- Studies have shown that nitrofurantoin is effective against many common uropathogens, including E. coli, and has a low resistance rate 6.
- However, the presence of nitrate-positive urine without WBCs does not necessarily confirm a UTI, and further testing and evaluation may be necessary to determine the cause of the symptoms 2.
WBCs and UTI Diagnosis
- The absence of WBCs in the urine does not necessarily rule out a UTI, as some patients may not exhibit pyuria despite having a UTI 4.
- Other factors, such as the presence of nitrate-positive urine, symptoms, and urine culture results, should be considered when diagnosing a UTI 2.
- It is possible to have a UTI with nitrate-positive urine without WBCs, and further evaluation and testing may be necessary to determine the cause of the symptoms 5, 6.