A recent paper, “Urinary Tract Infection”-Requiem for a Heavyweight by Dr Thomas Finucaine skillfully unpacks many key issues, coupling this with a consideration of the emerging knowledge of the urinary microbiome and virome, suggesting that the term “UTI” might better be referred to as a “urinary dysbiosis”. The paper is worth a detailed read – here is the start of the abstract –
“Urinary tract infection” (“UTI”) is an ambiguous, expansive, overused diagnosis that can lead to marked, harmful antibiotic overtreatment. “Significant bacteriuria,” central to most definitions of “UTI,” has little significance in identifying individuals who will benefit from treatment. “Urinary symptoms” are similarly uninformative. Neither criterion is well defined. Bacteriuria and symptoms remit and recur spontaneously. Treatment is standard for acute uncomplicated cystitis and common for asymptomatic bacteriuria, but definite benefits are few. Treatment for “UTI” in older adults with delirium and bacteriuria is widespread but no evidence supports the practice, and expert opinion opposes it….
We’ve previously mused on the issue of recurrent UTI in women and potential non-antibiotic management strategies. It is clear from one study at least that antibiotic treatment may increase subsequent risk of relapse and is associated with significant emergence or acquisition of bacterial resistance. (Clearly UTI associated with pyelonephritis or sepsis (bacteraemia) are not difficult to diagnose in the main and treatment requirements are unambiguous).
One of my hospital admissions this week illustrated this well – a 60 year old woman with recurrent UTI who represented with fever after recent treatment at another hospital of a UTI associated with this ctx-m1 ESBL Klebsiella (10-50 WC x 10^6/L in the microscopy):
She had received 3 days of intravenous piperacillin+tazobactam (TZP) (despite susceptibility result) and then 5 days of nitrofurantoin. Her symptoms of urinary frequency (she seldom gets dysuria) had resolved. We thought her fever possibly due to minor nitrofurantoin hypersensitivity and sent her home. Urine culture- no growth. Past history – typically 1-2 episodes per month of persistent urinary frequency with no past episodes of pyelonephritis nor sepsis. She’d tried topical vaginal oestrogen for 12 months with little impact on recurrence. Urological investigation found no significant anatomical issues . She’d received in excess of 10 courses of antibiotics over the previous 12 months. We encouraged her to consider restarting topical oestrogens, use of oral methenamine hippurate prophylaxis and encouraged her to ride out her symptoms as best she can, knowing that there is no danger in avoiding antibiotic treatment and potential longer term benefit.
Microbiology labs play a key part in the equation, given a) far too many urines get sent for culture with scant reason and b) the inadvertent reporting of positive culture antibiotic susceptibility inadvertently drives clinicians to antibiotic treatment – labs find it difficult to withhold results as few requests provide clinical notes to provide context. This is especially the case in residential aged care where there is such a low threshold for urine culture submission. As chronic bacteriuria is so prevalent in the elderly, a perfect storm of antibiotic treatment and resistance is created.
Perhaps in most situations, it’s sensible to avoid culture of urine (whatever lower tract symptoms, urine smell or a urinalysis result) and focus attention on those with potential sepsis whence blood cultures will be the best microbiological diagnostic indicator. Much scope for further research!
Finucane TE “Urinary Tract Infection”-Requiem for a Heavyweight. J Am Geriatr Soc. 2017 May 19.
Cai T, Nesi G, Mazzoli S et al. Asymptomatic bacteriuria treatment is associated with a higher prevalence of antibiotic resistant strains in women with urinary tract infections. Clin Infect Dis 2015;61:1655–1661.
- Lee BS, Bhuta T, Simpson JM, Craig JC. Methenamine hippurate for preventing urinary tract infections. Cochrane Database Syst Rev. 2012 Oct 17.