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Diagnosis of Urinary Tract Infection – Top Ten Myths in Adults

Diagnosis of Urinary Tract Infection – Top Ten Myths in Adults - Clinical Hub, UW Health Clinical Tool Search, UW Health Clinical Tool Search, Clinical Practice Guidelines, Infection and Isolation, Related


Last reviewed/revised: 10/2015
Diagnosis and Treatment of Infections of the Urinary Tract – Adult – Inpatient/Ambulatory Guideline
Appendix 1. Diagnosis of Urinary Tract Infection – Top Ten Myths
Authors: Lucas Schulz, PharmD, BCPS; Robert Hoffman, MD; Jeffrey Pothof, MD; Barry Fox, MD
For further reading consider:
1. Trautner BW, Grigoryan L, Petersen NJ, et al. Effectiveness of an Antimicrobial Stewardship
Approach for Urinary Catheter-Associated Asymptomatic Bacteriuria. JAMA Intern Med.
2015;175(7): 1120-1127.
2. Kalra R, Kraemer RR. Urinary catheterization -- when good intentions go awry: a teachable
moment. JAMA Intern Med. 2014;174(10): 1547-1548.
The diagnosis of UTI is not a laboratory defined diagnosis. The diagnosis should be based on
clinical symptoms combined with supportive laboratory information, if obtained.
Myth 1: The urine is cloudy and smells bad. My patient has a UTI.
Truth 1: Urine color and clarity or odor should not be used alone to diagnose or start antibiotic therapy in
any patient population.
a. Visual inspection of urine clarity is not helpful in diagnosing UTI in women.29
a. 100 female patients at a university hospital had their urine tested by reading newsprint
through the sample. The sensitivity, specificity, and positive and negative predictive
values were 13.3%, 96.5%, 40.0%, and 86.3% respectively.
b. Foul smelling urine is an unreliable indicator of infection in catheterized patients, and usually
dependent on a patients hydration status and concentration of urea in the urine.11,31
Myth 2: The urine has bacteria present. My patient has a UTI. Also see Myth 8.
Truth 2: The presence of bacteria in the urine on microscopic examination without UTI symptoms is NOT
recommended for the diagnosis of UTI due to the possibility of contamination and asymptomatic
bacteriuria35
a. UTI is not a laboratory defined diagnosis. Diagnosis should be based on clinical symptoms. The
bacterial thresholds (below) should usually be present in patients with a UTI; however, the
absence of bacteria does not rule out UTI in patients with clinical symptoms.
b. In patients without an indwelling catheter the following cutoffs should define significant
bacteriuria36
i. ≥ 105 CFU/mL of ≤ 2 species of microorganisms in voided culture
ii. ≥ 102 CFU/mL of any number of microorganisms in a straight cath culture
c. In patients with an indwelling catheter, ≥103 CFU/mL of any organism(s) should define significant
bacteriuria36 since this is predictive of higher colony counts of 10 to the fifth within 48 hours128
Myth 3: My patient’s urine sample has >5 squamous epithelial cells per low powered field and the
culture is positive. Because the culture is positive, I can disregard the epithelial cell count and
treat the UTI.
Truth 3: A good specimen has less than 5 epithelial cells per low power field on UA. Poor specimens
should be considered for recollection or straight catheterization should be performed.
Myth 4: The urine has positive leukocyte esterase. My patient has a UTI and needs antibiotics.
Truth 4: Urine leukocyte esterase should not be used alone to diagnosis or start antimicrobial therapy in
any patient population.
a. A dipstick leukocyte esterase test has high sensitivity and specificity for the presence of
quantitative pyuria, 80-90% and 95-98%, respectively; however a positive leukocyte esterase
Copyright © 2015 Univ ersity of Wisconsin Hospitals and Clinics Authority
Contact: Lee Vermeulen, CCKM@uwhealth.org Last Revised: 10/2015CCKM@uwhealth.org

Last reviewed/revised: 10/2015
Diagnosis and Treatment of Infections of the Urinary Tract – Adult – Inpatient/Ambulatory Guideline
alone is NOT recommended for diagnosis of UTI.32,33 Pyuria or bacteriuria alone is not an
indication for antimicrobial therapy
b. On rare occasions, a negative leukocyte esterase in the presence of UTI symptoms may still
prompt a urine culture if clinically suspected32,33 but especially prompt a search for urethritis,
vaginitis, or sexually transmitted infection.
Myth 5: My patient has pyuria. They must have a UTI.
Truth 5: Quantitative urine WBC should not be used alone to diagnosis or start antimicrobial therapy in
any patient population
a. In neutropenic or leukopenic patients, the WBC count may be artificially low and reflex culture
may not occur. The microbiology lab should be contacted and an order for urine culture ordered if
urinary symptoms are present and urinary source of infection is suspected.
b. Borderline WBC counts of 6-10 may reflect the patient’s state of hydration. Patients with oliguria
or anuria (dialysis) usually have some degree of pyuria.
c. Non-infectious conditions, such as sexually transmitted infections or non-infectious cystitis may
give pyuria.
Myth 6: The urine has nitrates present. My patient has a UTI.
Truth 6: Urine nitrates should not be used alone to diagnosis or start antimicrobial therapy in any patient
population.
a. Urine nitrate has a high true-positive rate for bacteriuria, but bacteriuria, as noted above in Myth
2, does not define a clinically significant UTI Diagnosis of UTI should be considered in a patient
with elevated urine nitrate in the presence of clinical signs and symptoms of UTI.32,35
b. A negative leukocyte esterase AND a negative urine nitrate largely rule out infection in pregnant
women, elderly patients, family medicine, and urology patients.34 Alternative diagnosis should be
thoroughly investigated in this scenario.
c. In an analysis of the negative predictive value for pathogenic bacteria using the combined nitrite
and leukocyte esterase dipstick analysis, the combination of a negative leukocyte esterase and
negative nitrite test demonstrated an NPV of 88% (CI: 84%-92%).
d. If both leukocyte esterase AND nitrite analyses are positive, the sensitivity for bacteriuria was
48% (CI: 41%-55%), and specificity was 93% (CI: 90%-95%).129 See Myth 2
Myth 7: All findings of bacteria in a catheterized urine sample should be diagnosed as a UTI.
Truth 7: Virtually 100% of patients with an indwelling Foley catheter are colonized within 2 weeks of
placement with 2-5 organisms. Colony counts of a catheter may define bacteriuria but must be taken in a
clinical context for making a diagnosis of UTI.
a. 98% of chronically catheterized patients had bacteriuria and 77% were polymicrobial. The mean
interval between new episodes of bacteriuria was 1.8 weeks.48
b. Bacteriuria and pyuria in chronically catheterized patients should only be treated in the presence
of signs and symptoms of infection (e.g. fever, leukocytosis, suprapubic pain and tenderness.
Dysuria is obviously unassessable). Pyuria or bacteriuria alone is not an indication for
antimicrobial therapy.
c. Patients with intermittent or condom catheters are at lower risk for UTI and should be considered
in the same risk category as those with no indwelling catheter.40
d. While antibiotics may delay the onset of bacteriuria in catheterized patients, this strategy
ultimately selects for resistant microorganisms. Prophylactic anti-infectives are not recommended
for patients with chronic catheters, but may be considered for short-term use by urology
specialists
Myth 8: Bacteriuria results in urinary tract infections and should be treated with antibiotics.
Truth 8: Bacteriuria does NOT establish a diagnosis of a UTI and does NOT necessarily require initiation
of antimicrobial therapy for asymptomatic bacteriuria.
Copyright © 2015 Univ ersity of Wisconsin Hospitals and Clinics Authority
Contact: Lee Vermeulen, CCKM@uwhealth.org Last Revised: 10/2015CCKM@uwhealth.org

Last reviewed/revised: 10/2015
Diagnosis and Treatment of Infections of the Urinary Tract – Adult – Inpatient/Ambulatory Guideline
a. The prevalence of bacteriuria in elderly institutionalized patient without indwelling catheters varies
from 25-50% for women and 15-49% for men and increases with age.5 Bacteriuria and pyuria in
the elderly is, to a large degree, an expected finding.
b. Symptomatic UTI is substantially less common than asymptomatic bacteriuria.
c. Asymptomatic bacteriuria has not been associated with long-term negative outcomes, such as
pyelonephritis, sepsis, renal failure or hypertension.47
d. The overuse of antibiotics leads to antibiotic resistance and potential side effects.16,17,19
e. Pyuria, leukocyte esterase, or nitrate, individually, accompanying asymptomatic bacteriuria are
NOT necessarily an indication for antimicrobial treatment in the general population.11 Some
exceptions include: pregnancy21 and patients with urinary tract stenting57
f. Recent evidence suggests that in younger women with true recurrent UTI, that bacteriuria may be
“protective” for future UTI with more pathogenic organisms.130
Myth 9: Falls and acute altered mental status changes in the elderly patient are usually caused by
UTI.
Truth 9: Altered mental status and falls in the elderly are caused by many factors. Other signs and
symptoms of UTI, especially dysuria (when able to assess) should be present to make the diagnosis of
UTI in non-catheterized patients. Symptoms of active infection in a catheterized patient are obviously
more difficult to assess.39
a. Elderly patients with acute mental status changes accompanied by bacteriuria and pyuria without
clinical instability or other signs or symptoms of UTI can reasonably be observed for resolution of
confusion for 24-48 hours without antibiotics131,132, while searching for other causes of confusion.
1. In all elderly patients, acute mental status change and functional decline are non-
specific clinical manifestations of several circumstances, including, but not limited to
dehydration, hypoxia, and poly-pharmacy adverse reactions. Diagnosis of UTI
should be correlated with others signs of systemic inflammation,
b. In the non-catheterized patient, acute changes in mental status was associated with bacteriuria
plus pyuria in patients with clinically suspected UTI.30
1. However, these two findings are also frequently demonstrated in elderly patients with
asymptomatic bacteriuria and attribution of altered mental status to bacteriuria can
result in failure to identify the true cause. 25,26,133 Falls without localizing urinary
symptoms were not associated with bacteriuria or pyuria.43,44
c. Elderly patients, especially those with dementia or indwelling Foley catheters, have high rates of
bacteriuria and may NOT have UTI symptoms5. Diagnosis of infection/sepsis of a urinary source
with simple bacteriuria is not recommended unless other infectious sources have been excluded
and patients meet urine criteria suspicious for infection. Diagnosis of UTI in the catheterized
patient should always be a diagnosis of exclusion by investigating other causes for altered mental
status in the absence of localized urinary tract findings.36
Myth 10: The presence of yeast or candida in the urine, especially in patients with indwelling
urinary catheters, indicates a candida UTI and needs to be treated.
a. The occurrence of candiduria in the catheterized patient is common, especially in the ICU and
most often reflects colonization or asymptomatic infection. Treatment of candida in the urine
should only occur in rare situations, such as clear signs and symptoms of infection and no
alternative source of infection
b. Treatment of asymptomatic candiduria in non-neutropenic catheterized patients has usually not
been shown to be valuable 134
c. “Treatment” of candiduria should first include replacement/removal of urinary tract instruments.
d. Except in selected highest risk transplant recipients, or immuno-compromised hosts who are
receiving steroids, or clinical scenarios for patients at high risk of systemic candidiasis, candiduria
has a low incidence of systemic complications , and conservative observation is usually indicated.
e. Isolation of candida in the urine of non- catheterized patients should second raise concerns about
vaginal or external contamination. If a reliable specimen is repeatedly obtained with yeast, and
the patient is symptomatic, consideration of anti-fungal therapy may be warranted.
Copyright © 2015 Univ ersity of Wisconsin Hospitals and Clinics Authority
Contact: Lee Vermeulen, CCKM@uwhealth.org Last Revised: 10/2015CCKM@uwhealth.org

Last reviewed/revised: 10/2015
Diagnosis and Treatment of Infections of the Urinary Tract – Adult – Inpatient/Ambulatory Guideline
References for Appendix 1. Diagnosis of Urinary Tract Infection – Top Ten Myths
1. Foley A, French L. Urine clarity inaccurate to rule out urinary tract infection in women. Journal of the
American Board of Family Medicine : JABFM. Jul-Aug 2011;24(4):474-475.
2. Nicolle LE. The chronic indwelling catheter and urinary infection in long-term-care facility residents.
Infection control and hospital epidemiology : the official journal of the Society of Hospital
Epidemiologists of America. May 2001;22(5):316-321.
3. Nicolle LE, Bradley S, Colgan R, Rice JC, Schaeffer A, Hooton TM. Infectious Diseases Society of
America guidelines for the diagnosis and treatment of asymptomatic bacteriuria in adults. Clinical
infectious diseases : an official publication of the Infectious Diseases Society of America. Mar 1
2005;40(5):643-654.
4. Van Nostrand JD, Junkins AD, Bartholdi RK. Poor predictive ability of urinalysis and microscopic
examination to detect urinary tract infection. American journal of clinical pathology. May
2000;113(5):709-713.
5. Stone ND, Ashraf MS, Calder J, et al. Surveillance definitions of infections in long-term care facilities:
revisiting the McGeer criteria. Infection control and hospital epidemiology : the official journal of the
Society of Hospital Epidemiologists of America. Oct 2012;33(10):965-977.
6. Tambyah PA, Maki DG. The relationship between pyuria and infection in patients with indwelling
urinary catheters: a prospective study of 761 patients. Archives of internal medicine. Mar 13
2000;160(5):673-677.
7. Pappas PG. Laboratory in the diagnosis and management of urinary tract infections. The Medical
clinics of North America. Mar 1991;75(2):313-325.
8. Bent S, Saint S. The optimal use of diagnostic testing in women with acute uncomplicated cystitis.
The American journal of medicine. Jul 8 2002;113 Suppl 1A:20S-28S.
9. Deville WL, Yzermans JC, van Duijn NP, Bezemer PD, van der Windt DA, Bouter LM. The urine
dipstick test useful to rule out infections. A meta-analysis of the accuracy. BMC urology. Jun 2
2004;4:4.
10. Sundvall PD, Gunnarsson RK. Evaluation of dipstick analysis among elderly residents to detect
bacteriuria: a cross-sectional study in 32 nursing homes. BMC geriatrics. 2009;9:32.
11. Warren JW, Tenney JH, Hoopes JM, Muncie HL, Anthony WC. A prospective microbiologic study of
bacteriuria in patients with chronic indwelling urethral catheters. The Journal of infectious diseases.
Dec 1982;146(6):719-723.
12. Loeb M, Bentley DW, Bradley S, et al. Development of minimum criteria for the initiation of antibiotics
in residents of long-term-care facilities: results of a consensus conference. Infection control and
hospital epidemiology : the official journal of the Society of Hospital Epidemiologists of America. Feb
2001;22(2):120-124.
13. Nicolle LE. Urinary tract infections in long-term-care facilities. Infection control and hospital
epidemiology : the official journal of the Society of Hospital Epidemiologists of America. Mar
2001;22(3):167-175.
14. Nicolle LE. Asymptomatic bacteriuria in the elderly. Infectious disease clinics of North America. Sep
1997;11(3):647-662.
15. Frank U, Kleissle EM, Daschner FD, et al. Multicentre study of antimicrobial resistance and antibiotic
consumption among 6,780 patients with bloodstream infections. European journal of clinical
microbiology & infectious diseases : official publication of the European Society of Clinical
Microbiology. Dec 2006;25(12):815-817.
16. Tacconelli E, De Angelis G, Cataldo MA, Pozzi E, Cauda R. Does antibiotic exposure increase the
risk of methicillin-resistant Staphylococcus aureus (MRSA) isolation? A systematic review and meta-
analysis. The Journal of antimicrobial chemotherapy. Jan 2008;61(1):26-38.
17. Burke JP. Antibiotic resistance--squeezing the balloon? JAMA : the journal of the American Medical
Association. Oct 14 1998;280(14):1270-1271.
18. ACOG Practice Bulletin No. 91: Treatment of urinary tract infections in nonpregnant women.
Obstetrics and gynecology. Mar 2008;111(3):785-794.
19. Paick SH, Park HK, Oh SJ, Kim HH. Characteristics of bacterial colonization and urinary tract
infection after indwelling of double-J ureteral stent. Urology. Aug 2003;62(2):214-217.
20. Cai T, Mazzoli S, Mondaini N, et al. The role of asymptomatic bacteriuria in young women with
recurrent urinary tract infections: to treat or not to treat? Clinical infectious diseases : an official
publication of the Infectious Diseases Society of America. Sep 2012;55(6):771-777.
Copyright © 2015 Univ ersity of Wisconsin Hospitals and Clinics Authority
Contact: Lee Vermeulen, CCKM@uwhealth.org Last Revised: 10/2015CCKM@uwhealth.org

Last reviewed/revised: 10/2015
Diagnosis and Treatment of Infections of the Urinary Tract – Adult – Inpatient/Ambulatory Guideline
21. Tambyah PA, Maki DG. Catheter-associated urinary tract infection is rarely symptomatic: a
prospective study of 1,497 catheterized patients. Archives of internal medicine. Mar 13
2000;160(5):678-682.
22. Beveridge LA, Davey PG, Phillips G, McMurdo ME. Optimal management of urinary tract infections in
older people. Clinical interventions in aging. 2011;6:173-180.
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24. Juthani-Mehta M, Quagliarello V, Perrelli E, Towle V, Van Ness PH, Tinetti M. Clinical features to
identify urinary tract infection in nursing home residents: a cohort study. Journal of the American
Geriatrics Society. Jun 2009;57(6):963-970.
25. Drinka PJ, Crnich CJ. Diagnostic accuracy of criteria for urinary tract infection in a cohort of nursing
home residents. Journal of the American Geriatrics Society. Feb 2008;56(2):376-377; author reply
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26. Nicolle LE. Urinary tract infections in the elderly. Clin. Geriatr. Med. Aug 2009;25(3):423-436.
27. Nicolle LE. Symptomatic urinary tract infection in nursing home residents. Journal of the American
Geriatrics Society. Jun 2009;57(6):1113-1114.
28. Kauffman CA, Vazquez JA, Sobel JD, et al. Prospective multicenter surveillance study of funguria in
hospitalized patients. The National Institute for Allergy and Infectious Diseases (NIAID) Mycoses
Study Group. Clinical infectious diseases : an official publication of the Infectious Diseases Society of
America. Jan 2000;30(1):14-18.
Copyright © 2015 Univ ersity of Wisconsin Hospitals and Clinics Authority
Contact: Lee Vermeulen, CCKM@uwhealth.org Last Revised: 10/2015CCKM@uwhealth.org