What findings indicate Urinary Tract Infection (UTI)?

From the Guidelines

Urinary tract infections (UTIs) are indicated by key findings such as dysuria, frequent urination, urgency, lower abdominal pain, and laboratory results showing positive leukocyte esterase and nitrites on urinalysis, pyuria, bacteriuria, and a positive urine culture with bacterial growth exceeding 100,000 colony-forming units per milliliter, as noted in the ACR Appropriateness Criteria for recurrent lower urinary tract infections in females 1.

Key Symptoms and Laboratory Findings

Some of the key symptoms of UTIs include:

• Painful urination (dysuria)
• Frequent urination
• Urgency
• Lower abdominal pain
• Cloudy urine
• Strong-smelling urine
• Blood in the urine (hematuria) Laboratory findings that indicate a UTI include:
• Positive leukocyte esterase and nitrites on urinalysis
• Pyuria (white blood cells in urine)
• Bacteriuria (bacteria in urine)
• A positive urine culture with bacterial growth exceeding 100,000 colony-forming units per milliliter, as typically revealed by a clean-catch or catheterized specimen for culture 1

Bacterial Causes and Risk Factors

UTIs occur when bacteria, most commonly Escherichia coli, enter and colonize the urinary tract, causing an inflammatory response 1. Women are more susceptible due to their shorter urethra, and other risk factors include:

• Sexual activity
• Urinary catheterization
• Urinary tract abnormalities
• Compromised immune systems
• Prior urinary tract surgery or trauma
• Gross hematuria after infection resolution
• Urea-splitting bacteria on culture
• Prior abdominopelvic malignancy
• Prior urinary tract calculi
• Prior diverticulitis
• Symptoms of pneumaturia, fecaluria, or repeated pyelonephritis 1

From the FDA Drug Label

The following in vitro data are available, but their clinical significance is unknown entrations (MIC’s) of 64 mcg/mL or less against most (≥ 90%) strains of the following microorganisms; however, the safety and effectiveness of fosfomycin in treating clinical infections due to these microorganisms has not been established in adequate and well-controlled clinical trials: Aerobic gram-positive microorganisms Enterococcus faecium Aerobic gram-negative microorganisms Citrobacter diversus Citrobacter freundii Enterobacter aerogenes Klebsiella oxytoca Klebsiella pneuomoniae Proteus mirabilis Proteus vulgaris Serratia marcescens

The findings that indicate a Urinary Tract Infection (UTI) include the presence of certain microorganisms, such as:

• Escherichia coli (E. coli)
• Enterococcus faecalis (E. faecalis)
• Other gram-positive and gram-negative aerobic microorganisms These microorganisms are associated with uncomplicated Urinary Tract Infections and are susceptible to fosfomycin, as indicated in the drug label 2.

From the Research

Findings Indicative of UTI

The following findings indicate a Urinary Tract Infection (UTI):

• Change in frequency, dysuria, urgency, and presence or absence of vaginal discharge are the most diagnostic symptoms of UTIs 3
• Dipstick urinalysis is a popular method for diagnosing UTIs, but results must be interpreted in context of the patient's pretest probability based on symptoms and characteristics 3
• Nitrites are likely more sensitive and specific than other dipstick components for UTI, particularly in the elderly 3
• Bacteriuria is more specific and sensitive than pyuria for detecting UTI, even in older women and during pregnancy 3
• Urine culture is the gold standard for detection of UTI, but asymptomatic bacteriuria is common, particularly in older women, and should not be treated with antibiotics 3
• Resistance to commonly used antibiotics such as trimethoprim-sulfamethoxazole, fluoroquinolones, and beta-lactams is increasing, making it essential to choose the right antibiotic for treatment 3, 4

Diagnostic Methods

Various diagnostic methods are used to diagnose UTIs, including:

• Dipstick urinalysis 3
• Microscopic urinalysis 3
• Urine culture 3, 5
• Kirby-Bauer disc diffusion system to test for antibiotic susceptibility 4

Treatment Options

Treatment options for UTIs include:

• Nitrofurantoin, fosfomycin, and trimethoprim-sulfamethoxazole as first-line treatments 3
• Beta-lactams, nitrofurantoin, fosfomycin, and trimethoprim-sulfamethoxazole as appropriate treatments in pregnancy 3
• Avoiding the use of trimethoprim-sulfamethoxazole as an empirical treatment due to increasing resistance rates 4