5.4 Treatment
5.4.1 General principles
Treatment strategy depends on the severity of the illness. Appropriate antimicrobial therapy and the management of the urological abnormality are mandatory. If needed, supporting care is given. Hospitalization is often necessary depending on the severity of the illness.
5.4.2 Choice of antibiotics
Empirical treatment of a symptomatic complicated UTI needs knowledge of the spectrum of possible pathogens and local antibiotic resistance patterns, and assessment of the severity of the underlying urological abnormality (including the evaluation of renal function).
Bacteraemia is usually reported too late to influence the choice of antibiotics. However, suspicion of bacteraemia must influence the empirical treatment. Most important for prognosis is still the severity of the associated illness and of the underlying urological condition.
Many therapeutic trials have been published on the use of specific antimicrobial therapies in complicated UTIs. Unfortunately, most reports are of limited use for the practical management of the patient in a day-to-day situation because of limitations such as:
Poor characterization of the patient populations
Unclear evaluation of the seventy of the illness
Nosocomial and community-acquired infections are not properly distinguished
Urological outcome is seldom taken into consideration
Intense use of any antimicrobial, especially when used on an empirical basis in this group of patients with a high likelihood of recurrent infection, will lead to the emergence of resistant micro-organisms in subsequent infections. Whenever possible, empirical therapy should be replaced by a therapy adjusted for the specific infecting organism(s) identified in the urine culture. Therefore, a urine specimen for culture must be obtained prior to initiating therapy, and the selection of an antimicrobial agent should be re-evaluated once culture results are available (7). So far, it has not been shown that any agent or class of agents is superior in a case where the infecting organism is susceptible to the drug administered.
In patients with renal failure, whether related to a urological abnormality or not, appropriate dose adjustments have to be made.
If empirical treatment is necessary, fluoroquinolones with mainly renal excretion are recommended because they have a large spectrum of antimicrobial activity covering most of the expected pathogens and they reach high concentration levels both in urine and the urogenital tissues. Fluoroquinolones can be used orally as well as parenterally. An aminopenicillin plus a BLI, a group 2 or 3a cephalosporin, or, in the case of parenteral therapy, an aminoglycoside, are alternatives.
In most countries, E. coli shows a high rate of resistance against TMP-SMX (18% in the last US evaluation) (16) and should therefore be avoided as a first-line treatment. Fosfomycin trometamol is licensed only for single-dose therapy of uncomplicated cystitis (17). The aminopenicillins, ampicillin or amoxicillin, are no longer sufficiently active against E. coli. In case of the failure of initial therapy, or if microbiological results are not yet available, or as initial therapy in the case of clinically severe infection, treatment should be switched to an antibiotic with a broader spectrum which is also active against Pseudomonas, such as a fluoroquinolone (if not used for initial therapy), an acylaminopenicillin (piperacillin) plus a BLI, a group 3b cephalosporin, or a carbapenem, eventually in combination with an aminoglycoside.
Patients can generally be treated as outpatients. In more severe cases (e.g. hospitalized patients), antibiotics have to be given parenterally and a combination of an aminoglycoside with a p-lactam antibiotic or a fluoroquinolone is widely used for empirical therapy. After a few days of parenteral therapy and clinical improvement, patients can be switched to oral treatment. Therapy has to be reconsidered when the infecting strains have been identified and their susceptibilities are known.
The successful treatment of a complicated UTI always combines effective antimicrobial therapy, optimal management of the underlying urological abnormalities or other diseases, and sufficient life-supporting measures. The antibacterial treatment options are summarized in Appendix 2.
5.4.3 Duration
of antibiotic therapy
Treatment for 7-14 days is generally recommended but the duration should be closely related to the treatment of the underlying abnormality (1). Sometimes, a prolongation for up to 21 days, according to the clinical situation, is necessary (2).
5.4.4 Complicated UTIs associated with urinary stones
If a nidus of either a stone or an infection remains, stone growth will occur. Complete removal of the stones and adequate antimicrobial therapy are both needed. Eradication of the infection will probably eliminate the growth of struvite calculi (18). Long-term antimicrobial therapy should be considered if complete removal of the stone can not be achieved (19).
5.4.5 Complicated UTIs associated with indwelling catheters
Current data do not support the treatment of asymptomatic bacteriuria, either during short-term catheterization (< 30 days) or during long-term catheterization, because it will promote the emergence of resistant strains (20,21). In short-term catheterization, antibiotics may delay the onset of bacteriuria, but do not reduce complications (22).
A symptomatic complicated UTI associated with an indwelling catheter is treated with an agent with as narrow a spectrum as possible, based on culture and sensitivity results. The optimal duration is not well established. Treatment durations that are both too short as well as too long may cause the emergence of resistant strains. A 7-day course may be a reasonable compromise.
5.4.6 Complicated UTIs in spinal-cord injured patients
It is generally accepted that asymptomatic bacteriuria in these patients should not be treated (23), even in case of intermittent catheterization. For symptomatic episodes of infection in the spinal-cord injured patient only a few studies have investigated the most appropriate agent and the most appropriate duration of therapy. Currently, 7-10 days of therapy is most commonly used. There is no superiority of one agent or class of antimicrobials in this specific group of patients.
Antimicrobial treatment options are summarized in Table 10.
Table 10: Antimicrobial treatment options for empirical therapy
Recommended
for initial empirical treatment
Fluoroquinolones
Aminopenicillin plus a BLI
Cephalosporin (group 2 or 3a)
Aminoglycoside
Recommended for empirical treatment in case of initial failure or for severe cases
Fluoroquinolone (if not used for initial therapy)
Ureidopenicillin (piperacillin) plus a BLI
Cephalosporin (group 3b)
Carbapenem
Combination therapy:
Aminoglycoside + (3-lactam antibiotic
Aminoglycoside + fluoroquinolone
Not recommended for empirical treatment
Aminopenicillins, e.g. amoxicillin, ampicillin
Trimethoprim-sulphamethoxazole (only if susceptibility of pathogen is known)
Fosfomycin trometamol
5.4.7
Follow-up after treatment
The greater likelihood of the resistance of micro-organisms involved in complicated UTIs is another feature of these infectious diseases. This is not a priori related to the urinary abnormality, but more to the fact that patients with a complicated UTI tend to have recurrent infection (7). For these reasons, prior to and after the completion of the antimicrobial treatment, urine cultures must be obtained for the identification of the microorganisms and the evaluation of susceptibility testing.