Can a clean urinalysis (UA) after treatment of Escherichia coli (E. coli) urinary tract infection (UTI) with persistent symptoms indicate a persistent infection?

Persistent UTI Symptoms with Clean Urinalysis After E. coli Treatment

Yes, persistent symptoms after E. coli UTI treatment despite a clean urinalysis can indicate a persistent infection. This situation requires further evaluation as it may represent bacterial persistence or relapse with the primary infecting organism.

Understanding Persistent Symptoms with Clean UA

• Patients with bacterial cystitis that recurs rapidly (within 2 weeks of treatment) after symptom resolution or who display bacterial persistence without symptom resolution may be reclassified as having a complicated UTI 1
• A clean urinalysis after treatment does not definitively rule out persistent infection, as bacteria may be present in lower numbers or in biofilm formations that aren't detected by standard urine culture methods 2
• Recent research shows that 77% of recurrent UTIs are caused by relapse with the primary infecting E. coli rather than reinfection with a new strain 2

Potential Mechanisms for Persistent Infection

• E. coli can invade and replicate within the bladder, forming biofilm-like intracellular bacterial communities (IBCs) that establish quiescent intracellular reservoirs, potentially causing recurrent UTIs 2
• Primary infecting E. coli causing persistence or relapse show higher biofilm formation capacity in vitro than those followed by cure or reinfection 2
• Standard urine culture methods may miss fastidious, anaerobic, and slow-growing uropathogens and rarely report polymicrobial infections 3

Evaluation of Persistent Symptoms

• For women whose symptoms do not resolve by the end of treatment, or whose symptoms resolve but recur within 2 weeks, a urine culture and antimicrobial susceptibility testing should be performed 1
• Causes of bacterial persistence include calculi, foreign bodies, urethral or bladder diverticula, infected urachal cyst, and postoperative changes that retain urine and result in stasis 1
• In patients with persistent or recurrent urinary incontinence, clinicians should perform history, physical examination, and/or other investigations to determine the cause 1

Management Approach

• For therapy in situations where symptoms persist despite clean UA, it should be assumed that the infecting organism is not susceptible to the agent originally used 1
• Retreatment with a 7-day regimen using another antimicrobial agent should be considered 1
• If symptoms persist despite appropriate antimicrobial therapy, imaging of the upper urinary tract (e.g., ultrasound, CT) should be considered to evaluate for diagnoses such as stones and hydronephrosis 1

Special Considerations

• Patients with recurrent UTIs (defined as at least three UTIs/year or two UTIs in the last 6 months) may require more extensive evaluation 1
• For patients with persistent symptoms and recurrent infections, clinicians should evaluate the upper and lower urinary tracts with imaging and cystoscopy 1
• E. coli strains from phylogenetic group B2 are more likely to cause persistence or relapse of infection compared to other groups 2

Pitfalls to Avoid

• Do not rely solely on urinalysis to rule out infection in patients with persistent symptoms after treatment 3
• Avoid treating asymptomatic bacteriuria, as this can lead to antibiotic resistance without clinical benefit 1
• Do not assume that a negative urine culture definitively rules out infection, as standard culture techniques have limitations in detecting certain uropathogens 3