Common misconceptions about urinary tract infection
Urinary tract infections (UTI) are common among women and hospitalized patients with an indwelling urinary catheter like Foley catheter.
A considerable number of patients, mostly in the community are subject to misdiagnosis and may be given unnecessary antibiotic therapy that they DO NOT need.
Schulz L, et al, provided the following comprehensive perspective regarding such misconceptions in the diagnosis and management of urinary tract infections:
Urine is Cloudy and Smells Bad.
Urine color and clarity or odor by itself are unreliable indicator of UTI and should not be used to start antibiotic therapy.
Urine has Bacteria Present.
The presence of bacteria in the urine on microscopic examination or by culture in patients with no signs or symptoms associated with UTI is not sufficient for the diagnosis of UTI.
Urine may contain bacteria due to contamination; or patients may have “asymptomatic bacteriuria” (described later), which is not uncommon in women of all ages.
Possible Contamination of Urine Culture.
In samples with >5 squamous epithelial cells under the microscopic examination suggests the possibility for contamination of urine sample. An attempt should be made to collect a “midstream clean catch” or “straight catheter” urine sample.
Presence of white blood cells (WBC) in urine known as “Pyuria”.
Presence of WBC in urine alone, should not be used make a diagnosis of UTI or start empiric antimicrobial therapy.
A low level increase in urine WBC is seen in patients with dehydration or kidney dysfunction such as renal failure. Similarly, WBC may also be present in urine in conditions associated with presence of blood in the urinary tract.
Acute renal failure, sexually transmitted infections, and noninfectious inflammation of the urinary bladder “cystitis” may also cause WBC to be present in patients’ urine sample.
Urine has Positive Leukocyte Esterase.
Presence of leukocyte esterase alone is not sufficient for establishing diagnosis of UTI and/or commence antibiotic therapy.
As mentioned with pyuria alone, a high positive leukocyte esterase is NOT sufficient by itself for the diagnosis of UTI.
A negative leukocyte esterase in patients with UTI symptoms should prompt a search for other infections such as urethritis, vaginitis, or sexually transmitted infection.
Nitrates Present in the Urine.
Urine nitrates should not be used alone to diagnosis or start antimicrobial therapy in any patient population. Presence of nitrates may also reflect presence of “asymptomatic bacteriuria”.
Bacteriuria if not Treated May Progress to a Serious Infection.
Presence of bacteriuria DOES NOT establish diagnosis of UTI. Antimicrobial therapy should not be initiated in asymptomatic patients, with the exception of patients with severe immune dysfunction, kidney transplantation and those with severe neutropenia (very low blood white cell count).
Bacteriuria and pyuria may be seen in elderly nursing home population; and in a good number of these patients these finds occur even in the absence of an infection. Therefore, by itself these findings should not trigger antibiotic therapy.
Asymptomatic bacteriuria has not been associated with “down the road” risk for kidney infection (pyelonephritis), blood borne infection (bacteria or sepsis) or loss of kidney function (renal failure) or high blood pressure (hypertension).
Some exceptions to the above statement are a) pregnancy and b) following urologic procedure with bleeding, such as placement of urinary tract stents and other foreign devices.
Presence of Yeast (Candida) in Urine (Candiduria) Indicates Yeast UTI.
Patients with a urinary catheter may frequently have candiduria, and in most instances this represents colonization or asymptomatic infection.
Treatment of Candida in the urine should be undertaken once diagnosis of infection has been well-established and there is no alternative source of infection.
Patient who exhibit candiduria have a low risk for a widespread (systemic) fungal infection infection such as presence of yeast in the blood circulation called fungemia or candidemia.
Isolation of Candida in a urine sample from a patient without urinary catheter, should raise concerns for vaginal or external contamination.
Patients with severe disorders of immune function, presence of candiduria requires a thorough investigation for the possibility of a local or a systemic infection.
Please take note,
A positive urine culture without signs and symptoms of UTI known as “asymptomatic bacteriuria” is common in all age groups of women and is frequently over treated with antibiotics.
Diagnosis of UTI requires:
- Presence of clinical signs & symptoms consistent with a urinary tract infection
Plus
- Laboratory information that highlights presence of a pathogen (bacteria; nitrates) and evidence of inflammation of the urinary tract (pyuria, leukocyte esterase, hematuria).
The overuse of antibiotics has been recognized as the leading cause for global spread of antibiotic resistance among common human pathogens.
Unnecessary antibiotic therapy also underscores the grave concern for the risk of developing serious drug-related adverse events (side effects), which can be life-threatening.
Schulz L, Hoffman RJ, Pothof J, Fox B. Top Ten Myths Regarding the Diagnosis and Treatment of Urinary Tract Infections. J Emerg Med. 2016 Jul;51(1):25-30.