Stop Those Urinary Tract Infections – Cranberry Juice to the Rescue
A 75-year-old female presents with the chief complaint
of fever, chills, and right-flank pain. She also has frequency
and urgency and occasional stress incontinence. She
has a history of recurrent urinary tract infections (UTIs),
all managed successfully with oral antibiotics. The physical
examination reveals moderate right costovertebral
angle (CVA) tenderness. The pelvic exam reveals atrophic
vaginal mucosa and a moderate cystourethrocoele. The
urinalysis reveals 8-10 white blood cells per high-power
field (WBCs/HPF) with bacteriuria. The complete blood
count (CBC) has 26,000 WBCs. The urine culture has
greater than 105 colony-forming units (CFUs)/mL
Escherichia coli sensitive to gentamicin and ciprofloxacin.
A blood culture is negative.
Urinary tract infections are a common condition
among the elderly population. Urinary tract infections
increase with age but are not considered part of the normal
aging process. Historically, UTIs are defined by the
presence of pyuria, bacteriuria, and greater than 105
CFUs/mL on a clean-catch midstream specimen. A more
current definition is the presence of as few as 103
CFUs/mL in symptomatic patients or when a specimen is
obtained by sterile catheterization.
Pathophysiology of UTIs in Older Adults
There is evidence that the aging urinary tract is associated
with a decrease in cell-mediated immunity, and as a
result, the older patient is more susceptible to UTIs than
younger patients. There may be altered bladder defense
mechanisms that increase uroepithelial receptivity to bacteria.
Other antibacterial factors also decrease with aging.
For example, in women who are postmenopausal, there is
a decrease in vaginal estrogen. As a result, there is an
increase in the vaginal pH secondary to a decrease in the
normal flora of lactobacilli. The consequence of this
change in the normal vaginal flora is an increase in more
pathogenic bacteria from the gastrointestinal tract.
In older men, benign prostatic hyperplasia (BPH) causes
compression of the urethra and leads to bladder outlet
obstruction. As a result, there is incomplete emptying of
the bladder, which leads to urinary stasis and predisposes
men to bladder infections.
Additional risk factors for UTIs in the elderly include:
becoming critically ill and/or losing bladder control
and requiring the use of a catheter, a common source
a history of diabetes, sickle-cell anemia, HIV, or
other disorder that weakens the immune system;
abuse of analgesics; kidney stones
loss of estrogen and a thinning vaginal and urethral
lining in menopausal or postmenopausal women
The most common pathogens are gram-negative bacilli.
E. coli is the most common organism, but its prevalence
decreases with advancing age, and the more virulent
organisms such as Proteus, Klebsiella, Providencia,
Citrobacter, and Pseudomonas occur in the geriatric population.
Gram-positive infections with organisms such as
Enterococcus faecalis are also prevalent in the elderly.1
Infections with urea-splitting organisms such as Proteus
and Klebsiella species are often associated with struvite
nephrolithiasis. It is not uncommon to see infections with
multiple organisms in older persons, and these should not
always be assumed to be associated with contamination of
the urine specimen.
Diagnosis and Work-up
Patients may not manifest classic UTI signs and symptoms
such as dysuria, frequency, urgency, and nocturia.2-4
Mental status changes, fever, back pain, suprapubic tenderness,
unstable gait, and falls are atypical presentations of
UTIs in older adults.2,3 Clinicians should rule out other serious
medical conditions before making a diagnosis solely of a
UTI in an elderly patient with an atypical presentation.3
Often, older persons will present without any urinary
symptoms and may present with respiratory symptoms
such as cough and dyspnea. Some of these patients have a
negative chest x-ray and have been treated for pneumonia.
Nearly one-third of elderly patients with a UTI will
present with confusion. Only 20% will have urinary
The urinalysis is the easiest and most helpful diagnostic
test to evaluate a UTI in the older person. The most common
findings on the dipstick test are a positive leukocyte
esterase and nitrate test. Microscopic examination of a
centrifuged clean-catch midstream urine will reveal the
presence of WBCs/HPF and often visible bacteriuria.
A positive urinalysis provides a presumptive diagnosis
of a UTI and can be confirmed with a urine culture. In
the past, more than 105 CFUs/mL from a clean-catch
specimen was considered confirmatory evidence of a
UTI; however, fewer bacteria may be significant and
indicate a UTI if the specimen is obtained by urethral
catherization. Asymptomatic bacteriuria may represent
contamination with skin or vaginal flora. Isolated pyuria
may be associated with a noninfectious inflammatory
condition such as interstitial cystitis or genitourinary
The mainstay of UTI diagnosis in the elderly consists
of urinalysis, urine culture, and antibiotic sensitivity
testing.2 Clean-catch urine samples may not be easy to
obtain in older patients; in-and-out catheterization and
suprapubic aspiration may be necessary. The presence of
nitrates and leukocyte esterase on dipstick urinalysis are
less useful in the geriatric population than in younger
patients. While culture is necessary to diagnose infection
in the elderly, final diagnosis depends on clinician interpretation
of the patient as being symptomatic.
Asymptomatic bacteriuria is defined as 105 CFUs/mL in
a patient without signs or symptoms. Infection is diagnosed
with as few as 103 CFUs/mL in the symptomatic
elderly patient.4 Furthermore, culture and sensitivity
testing allows identification of causative organisms and
their antibiotic resistance patterns, which is especially useful in institutionalized and catheterized patients and
in those with a history of antibiotic treatment.2
E. coli, the predominant cause of UTI in younger
patients, remains an important, though less predominant,
cause in older adults. Proteus mirabilis, Klebsiella
pneumoniae, Enterococcus faecalis, group B streptococci,
and coagulase-negative staphylococci are also important
pathogens.2-5 Polymicrobial UTIs are more common in
elderly patients, especially those who are institutionalized
and catheterized. Long-term catheter use is associated
with infection by gram-negative rods,2,4 although
Enterococcus and methicillin-resistant Staphylococcus
aureus may also be involved. Urinary tract infections of
fungal origin are an additional source of infection in
patients with indwelling catheters. Catheter and antibiotic
use also places patients at risk for more resistant
pathogens, such as Pseudomonas aeruginosa, Enterobacter,
Citrobacter, and Serratia marcescens.2
Treatment of Uncomplicated UTIs
The clinician should initiate empiric therapy for
uncomplicated infections, since medication can be adjusted
once antibiotic sensitivity data become available.2 Oral
fluoroquinolones are considered first-line agents for
uncomplicated cystitis in patients of both genders. Elderly
women should be treated for 10 days and men for 14 to
28 days. Trimethoprim-sulfamethoxazole is an additional
first-line agent for women only. Second-line agents
include amoxicillin/clavulanate potassium, second- and
third-generation cephalosporins, and nitrofurantoin. A
trial of topical estrogen therapy may help to prevent UTIs
in elderly women.2-5 Several factors determine which
antibiotics are prescribed, including effectiveness, cost,
side effects, and the possibility that the antibiotic could
contribute to the development of bacterial resistance in
serious infections. Some treatment guidelines follow:
The use of broad-spectrum antibiotics to treat
simple infections, such as uncomplicated UTIs, may
lead to the development of resistance in the treatment
of more serious infections. For this reason some
experts advise reserving broad-spectrum antibiotics
for more serious infections and using narrow-spectrum
Take the time to speak with patients about the
rationale for the use, or non-use, of antibiotics. If an
antibiotic is prescribed, explain how to properly use
the antibiotic and the importance of patient adherence
to these instructions, including finishing the prescription
even if symptoms disappear to ensure that all bacteria
Before antibiotics begin to take effect, patients can
relieve some discomfort with a heating pad or a warm bath.
Patients should drink fluids in order to dilute the
bacteria within the urinary tract. Drinking cranberry
juice may diminish bacterial adherence to the bladder
wall, thus enhancing bacterial eradication.
Treatment of Complicated UTIs
Complicated UTIs in older persons include acute
pyelonephritis, urinary retention, hydronephrosis, renal
abscess, and acute prostatitis. These patients are usually
sick, febrile, have nausea, and may be markedly debilitated.
Elderly patients who are unable to tolerate oral fluids
and who are febrile should probably be admitted to the
hospital to receive parenteral fluids and antibiotics.
For patients with acute pyelonephritis, the recommendation
is to use drugs that provide high kidney tissue levels.
Aminoglycosides and fluoroquinolones achieve higher real
tissue levels, relative to serum levels, than do beta-lactams.6,7
It is important to know the antimicrobial susceptibility
profile of uropathogens in your community to help guide
the therapeutic decisions for the empiric treatment of
acute pyelonephritis. In our community, the drugs of
choice are a fluoroquinolone and an aminoglycoside,
which require close monitoring of the BUN/creatinine
levels in patients with decreased renal function. If enterococcus
is suspected based upon the Gram stain, ampicillin
(1-2 g IV/every 6 hr) plus the aminoglycosides are appropriate
Once the patient is afebrile, the WBC has returned to
normal, the patient can tolerate oral fluids, and the results
of the blood and urine cultures are back, the patient can
be switched to oral antibiotics based on the sensitivity
testing of urine and blood cultures.
Duration of therapy remains controversial. Six-week
regimens are not more effective than 14-day regimens for
pyelonephritis. Not only is the cost a consideration, but
the longer regimen is associated with more side effects.7
Follow-up therapy consists of a repeat urine culture 1-2
weeks after completion of therapy.
Patients with urinary retention or hydronephrosis with
infection need the insertion of a catheter or the insertion
of a ureteral stent, respectively, to relieve the obstruction.
Failure to do so in a timely fashion can risk the development
For patients with symptoms of pyelonephritis who do
not respond to initial antibiotic therapy, a renal abscess
must be ruled out. This can often be detected on a computed
tomography (CT) scan or a nuclear medicine gallium
scan, as was the case with this patient. These patients
need percutaneous drainage of the abscess or, occasionally,
an open surgical procedure to drain the abscess fluid
(see the “Outcome of the Case Patient” section).
Catheter-related symptomatic infections require sterile
replacement of the indwelling catheter and treatment with a broad-spectrum antibiotic. Options include 2-3 weeks
of ampicillin plus gentamicin, a third-generation
cephalosporin, piperacillin/tazobactam, aztreonam, or a
carbapenem.2,5 Treat Candida albicans with 3-5 days of oral
fluconazole; treat severe symptomatic catheter-related
infections with other Candida species with amphotericin
B bladder irrigation. Limiting the use of indwelling
catheters is the best strategy for preventing UTIs.2
Asymptomatic Bacteriuria in Older Adults:
Definition and Diagnosis
The term asymptomatic bacteriuria refers to the presence
of high quantities of a uropathogen in the urine of a
patient who has no urinary complaints such as burning,
frequency, or pain, or other clinical symptoms as noted in
the description of symptomatic UTIs. It is not well
understood why certain patients do not develop symptoms,
as the organisms recovered are the same as those
that cause symptomatic UTIs, with the most common
being E. coli. Up to 20% of elderly men and women may
have bacteriuria without symptoms.8 Although early studies
noted an association between bacteriuria and excess
mortality, more recent studies have failed to demonstrate
any such link.9 In fact, aggressively screening elderly persons
for asymptomatic bacteriuria and subsequent treatment
of the infection has not been found to reduce either
infectious complications or mortality.
The 2005 Infectious Diseases Society of America (IDSA)
guidelines for the diagnosis and treatment of asymptomatic
bacteriuria in adults recommend the following criteria for
the diagnosis of asymptomatic bacteriuria:
For asymptomatic women, bacteriuria is defined as
two consecutive clean-catch voided urine specimens with isolation of the same bacterial strain in counts
greater than or equal to 105 CFUs/mL.10
For any asymptomatic patient, bacteriuria is defined as a
single catheterized urine specimen with one bacterial
species isolated in counts greater than or equal to
102 CFUs/mL.10 A more practical definition that is
used by most clinicians is 103 CFUs/mL.
Treatment of Asymptomatic Bacteriuria.
the 2005 IDSA guidelines there are no clinical benefits of
screening for or treatment of asymptomatic bacteriuria.11-13
There was no decrease in the rate of symptomatic infection
or improvement in survival12,13 in those patients who were
treated with antibiotics, and there were no changes in
chronic genitourinary symptoms12 associated with antimicrobial
therapy. Treatment of asymptomatic bacteriuria was
associated with significantly increased adverse antimicrobial
effects and reinfection with organisms of increasing
The IDSA does NOT recommend regular screening
and treatment of asymptomatic bacteriuria in the elderly
due to the high costs and increased antimicrobial resistance
due to repeated antibiotic treatments. However, if
these patients have a genitourinary procedure planned,
such as cystoscopy, it is recommended that they receive
preoperative antibiotic therapy.
Outcome of the Case Patient
This patient had clinical pyelonephritis and was started
on intravenous gentamicin and ciprofloxacin. A CT scan revealed a cystic mass in the lower pole of
the right kidney. She became afebrile in 48
hours, but the right CVA pain persisted.
The follow-up CBC showed only a modest
decrease in her WBC. A gallium scan was
ordered, and at 48 hours this demonstrated
an accumulation of radioactivity in the area
of the right kidney in the region of the cystic
mass described by the previous CT scan
(Figure). A follow-up CT scan demonstrated
a mass in the lower pole of the right kidney
compatible with a perinephric abscess.
With CT guidance the abscess was drained
percutaneously, and the drain was left in
place for 48 hours. Her pain subsided, her
WBC returned to normal, and she was discharged
on oral antibiotics for 2 weeks. Follow-up urinalysis
and renal ultrasound were normal.
The authors report no relevant financial relationships.
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article/000520.htm. Accessed July 2, 2008.
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of Nephrology; American Geriatric Society. Infectious Diseases Society of America
guidelines for the diagnosis and treatment of asymptomatic bacteriuria in adults [published
correction appears in Clin Infect Dis 2005;40(10):1556]. Clin Infect Dis
11. Nicolle LE, Mayhew WJ, Bryan L. Prospective, randomized comparison of therapy
amd no therapy for asymptomatic bacteriuria in institutionalized elderly women. Am
J Med 1987;83:27-33.
12. Nicolle LE, Bjornson J, Harding GK, MacDonell JA. Bacteriuria in elderly institutionalized
men. N Eng J Med 1983;309:1420-1425.
13. Abrutyn E, Mossey J, Berlin JA, et al. Does asymptomatic bacteriuria predict mortality
and does antimicrobial treatment reduce mortality in elderly ambulatory women
[published correction appears in Ann Intern Med 1994;121(11):901]. Ann Intern
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