© The Canadian Journal of Urology™; 19(Supplement 1); October 2012
Mazzulli
46
Neither amoxicillin or ampicillin is recommended
as an empiric treatment for uncomplicated cystitis,
due to the relatively poor efficacy and the high rates of
resistance to these agents. However, because of their
relative safety, these agents continue to play a role in
the management of pregnant women with UTIs.
It is important to recognize that the IDSAtreatment
recommendations are limited to premenopausal
women without comorbidities such as diabetes or
urological abnormalities, and therefore they cannot
be directly applied to all patient populations in the
outpatient setting including the elderly.
14
Because most therapy for uncomplicated cystitis is
administered empirically, an assessment of potential
risk factors for antimicrobial resistance is needed prior
to prescribing a treatment agent. The most important
identified epidemiologic risk factor is exposure to
the antibiotic in the previous 3 to 6 months. This
was found to be an independent risk factor for TMP-
SMX resistance in women with acute, uncomplicated
cystitis.
14,16,37,38
Prior exposure to other agents has
been less well studied, but reports suggest that the
same phenomenon may occur, and thus consideration
should be given to using an agent other than one that
has been recently prescribed.
39
Forpatientswithacute,uncomplicatedpyelonephritis,
including those with severe infection and bacteremia, a
recent study found that a 7-day course of ciprofloxacin
was not inferior to a 14-day course of therapy.
40
Although limiting patient exposure to antibiotics and
thus possibly reducing antimicrobial selection pressure
for resistant organisms is desirable, the results of this
study cannot be extrapolated to other agents, and
thus 10 to 14 days of treatment should be prescribed
when using non-fluoroquinolone agents for treatment
of uncomplicated pyelonephritis. The relatively high
rates of fluoroquinolone resistance in some regions/
settings includingESBL-producing organismsmay limit
this short-course treatment in these situations. Oral
ciprofloxacin for 7 days can be used for patients who do
not require hospitalization, if the prevalence of resistance
of community uropathogens to fluoroquinolones does
not exceed 10%.
14
If the pathogen is known to be
susceptible, then oral TMP-SMX twice daily for 14 days
may be used. Alternatives include a third-generation
cephalosporin or once-daily aminoglycoside. For
womenwithpyelonephritis requiringhospitalization for
treatment, initial therapy should be given parenterally
with either a fluoroquinolone, a third-generation
cephalosporin, an aminoglycoside plus/minus
ampicillin, or a carbapenem. Treatment should be
tailoredonce an organismis identified and antimicrobial
susceptibility results are available.
Complicated UTIs
Treatment recommendations for patients with
complicated UTIs are much less well defined. This
likely reflects the varied types of patient populations
who have this type of UTI. The choice of empiric
antimicrobial therapy will depend on an assessment
of multiple factors including antimicrobial resistance
rates, presence of comorbid conditions (including
assessment of renal function), drug interactions,
ability of the patient to take oral antibiotics, and
history of drug allergies. Initial empiric parenteral
therapy with a fluoroquinolone, a carbapenem (e.g.,
ertapenem, meropenem, or imipenem), a third-
generation cephalosporin (e.g., ceftriaxone, cefotaxime,
etc.), or a piperacillin/tazobactam may be required.
41
Resistance to TMP/SMX is frequently seen in most
cases of complicated UTIs, and it is not recommended
for empiric therapy in these cases. As noted earlier, for
patientswithuncomplicated cystitis andpyelonephritis,
ESBL-producing organisms also appear to be increasing
in the hospital setting, rendering many of the agents
listed above ineffective except for the carbapenems.
The recommended treatment duration for patients with
complicated cystitis is 7 to 10 days (3-day, short-course
therapy is not recommended), and the recommended
treatment duration for complicated pyelonephritis is
10
to 14 days.
42
Prophylaxis
The use of antimicrobial agents as prophylaxis for
recurrent cystitis has been shown to be effective in
reducing the risk of recurrences by close to 95%.
43,44
Concern, however, stems from the risk of continued
exposure to antimicrobial agents and the potential
emergence of resistance. Current recommendations are
to limit the use of antimicrobial agents for prophylaxis
of UTIs to women with three or more infections in the
past 12 months, or those with two or more infections
in the past 6 months in which at least one episode was
documented by a positive urine culture.
7
The optimal
duration of antimicrobial prophylaxis is not known, but
continued evaluationof the patient shouldbe performed
with consideration to discontinue it after 3 to 6 months.
Approximately 50% of women will experience a UTI
within 3 months of discontinuation of prophylaxis,
at which point re-institution of prophylaxis should
be considered.
44
At present, there is no evidence to
support the use of antimicrobial prophylaxis for routine
prevention of catheter-associated UTIs, and thus it
should not be used for this purpose.
4
Multiple non-pharmacologic strategies have been
tried for the prevention of recurrent UTIs, despite the
fact that data supporting many of these approaches
