Dr. med. Dirk Manski

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Urinary Tract Infections: Antibiotic Treatment and Prevention

Review literature: (Krieger, 2002) (Nickel, 2005a) (Nickel, 2005b) (Sussman and Gally, 1999) (Wagenlehner and Naber, 2006) (DGU 2009, S3-guideline for UTI).

Non-pharmacological Prevention of Urinary Tract Infections

Fluid intake:

The increase of fluid intake (water) and thus the diuresis to about 1.5–2 l prevents UTIs. Excessive drinking is not recommended as it dilutes antibacterial substances in the urine.


Obesity increases the risk of UTI by a factor of 2.5–5. An additional preventive effect can be expected from the consumption of fruit juices from berries and dairy products with probiotic bacteria.


Regular consumption of cranberry juice or concentrate (twice daily) reduces the frequency of urinary tract infections (RR 0.6). Cranberries interact with the adherence of the bacteria with the urothelium, but the extent of their effectiveness is controversial.

Personal hygiene:

Hygiene measures can damage the vitality of lactobacilli in the vagina. Exaggerated genital hygiene, intimate sprays and bidet rinses should be avoided. Pantyliners or pads rather than tampons are recommended as menstrual hygiene products.

Sexual Behavior and Urinary Tract Infections

The frequency of urinary tract infections correlates with the frequency of sexual contact. Urinary tract infections can be prevented by micturition immediately after sexual intercourse, avoiding anal intercourse, and avoiding using diaphragm or spermicides. In case of frequent UTIs following sexual intercourse, the single-dose administration of an antibiotic is a treatment option.

Pharmacological Prevention of Urinary Tract Infections


Oral vaccination with inactivated but immunogenic E. coli strains (e.g., Uro-Vaxom in a single daily dose for three months) shows a protective effect, reduction of the recurrence rate by 22–65% over 6–12 months (Bauer et al., 2002).

An intramuscular vaccine is also effective in controlled trials, reducing UTI recurrence and breakthrough infections between 26–93% compared to a placebo (Vahlensieck et al., 2014). Dosage of Strovac or Perison: three intramuscular injections for the primary immunization every two weeks. Refreshing injections are done afterward in an yearly intervall.


Two grams of D-mannose once daily reduces (RR 0.24) the frequency of urinary tract infections (Kranjcec et al., 2014). The excretion of D-mannose in the urine occupies the fimbriae of the coliform bacteria and reduces their adherence to the urothelium. Increased dosages (up to 2 g thrice a day) are used to treat active UTIs and prevent antibiotic treatment.

Vaginal estrogenization:

In postmenopausal women with recurrent urinary tract infections, vaginal estrogenization reduces the frequency of urinary tract infections. The vaginal application as a capsule, ointment, or ring with estrogen release is more successful and has fewer side effects than oral hormone replacement therapy.

Low-dose antibiotic prophylaxis:

Low-dose antibiotic prophylaxis is considered an effective method of avoiding recurrent urinary tract infections in patients with severe symptoms or complications. The dosage is recommended once a day in the evening; alternatively, a single intake after sexual intercourse is possible. Possible preparations and dosages: Nitrofurantoin 50–100 mg, Trimethoprim 50–100 mg or Cotrimoxazole 240–480 mg. Disadvantages of low-dose antibiotic prophylaxis are side effects, increasing resistance, and the frequently unchanged recurrence rate after the end of the antibiotic long-term prophylaxis (Kranz et al., 2017). Caution: due to dangerous side effects, fluoroquinolones such as ofloxacin 100 mg, ciprofloxacin 125 mg, or norfloxacin 200 mg are no longer approved for antibiotic prophylaxis (EAU Guidelines) (Drug Safety Mail 2019-40).

Prevention of Catheter-Associated UTI


Careful aseptic techniques for catheterizations have a short-term effect in preventing UTIs. Despite all measures, the urinary bladder will be colonized with bacteria after a few days with a bladder catheter. Standard care is the use of closed drainage bags, free flow of the depending drainage system, positioning of the bag consistently below the bladder level, and aseptic techniques when opening the closed system.

Suprapubic catheter:

Transurethral catheters cause a slightly higher rate of urinary tract infections in the perioperative setting as compared to suprapubic catheters. For more extended periods of catheterization, no differences are detectable. A clear advantage of suprapubic catheters is minimizing the trauma to the male urethra and preventing urethral strictures.

Intermittent catheterization:

Intermittent catheterization is the method of choice for bladder emptying disorders as an alternative to indwelling catheters. Guidelines of the EAU and DGU endorse the use of aseptic techniques for intermittent catheterization.

Acidification of urine:

Methenamine hippurate or mandelate combined with L-methionine for urinary acidification are used to prevent CAUTI. Methenamine salts are not suitable for prolonged use (Lee et al., 2012) (Hooton et al., 2010), and the drug is no longer available in Germany. Methenamine salts have a low rate of side effects and are an option for short-term prophylaxis, especially for patients with bladder catheter after surgery (Schioetz et al., 2006).

Change of Bladder Catheter:

A new bladder catheter is needed if there is insufficient urine flow due to encrustation or an antibiotic treatment due to CAUTI is initiated. Routine changes of bladder catheter for symptom-free patients should be adjusted individually (every 1-3 months).

Unsuccessful prevention and treatment approaches:

Management of Asymptomatic Bacteriuria

The prevalence of asymptomatic bacteriuria is high: 5% in healthy premenopausal women, 4-19% in old healthy patients, and up to 90% in patients with risk factors (age, diabetes, neurological disorders). Only a tiny proportion of these patients will experience symptomatic UTI in the following weeks to months. In some cases, the studies showed an increase in the UTI rate due to therapy for bacteriuria; this suggests a protective effect of asymptomatic colonization (Cai et al., 2012). For the following risk groups, in the absence of symptoms (dysuria, fever, pain), screening (ordering a urine culture without symptoms) or prophylactic antibiotic therapy is not indicated (EAU guideline UTI):

For two risk groups, studies have demonstrated an advantage of screening and treatment of asymptomatic bacteriuria:

Antibiotic Treatment in Urinary Tract Infections

Initial Antibiotic Treatment:

Initial antibiotic treatment takes into account possible existing urine culture results. In the case of acute infections, a calculated initial therapy is started (after collection of urine specimens for culture). The following table gives an overview about the antibiotic resistance of bacteria in uncomplicated UTI.

Antibiotic options for the treatment of acute cystitis, sorted by resistance to E. coli from several studies (German Guideline UTI). (*) Amoxicillin/clavulanic acid.
Antibiotikum Sensibel Resistent
Pivmecillinam 98% 1%
Fosfomycin 96% 1%
Cefuroxim 89% 2%
Amox./Clav. (*) 87% 3%
Nitrofurantoin 86% 5%
Ciprofloxacin 92% 7%
Nalidixinsäure 91% 9%
Cotrimoxazol 74% 26%
Ampicillin 57% 38%

For organ-specific diagnosis and calculated initial therapy, see the following sections: bladder infection, gonorrhea, urinary tract infections in pregnancy, pyelonephritis, bacterial prostatitis, epididymitis and urosepsis.

Duration of Antibiotic Treatment in Urinary Tract Infections:

The duration of antibiotic therapy for urinary tract infections without the involvement of parenchyma is about three days (e.g., cystitis in women). In men, only urethritis can be regarded as an infection without parenchymal involvement. The treatment duration for UTI with involvement of the parenchyma should last 7–14 days, depending on the severity and response to the initial calculated antibiotic treatment. In bacterial prostatitis, some authors recommend four weeks of antibiotic treatment to prevent chronic prostatitis. In recurrent urinary tract infection, it is important to identify risk factors (e.g., sexual behavior, vesicoureteral reflux, bladder stones or obstruction) to enable a causative treatment. Without risk factors, long-term antibiotic treatment is an option (see above).

Index: 1–9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


Deutsche Gesellschaft für Urologie, S3-guideline for urinary tract infection
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Bauer u.a. 2002 BAUER, H. W. ; RAHLFS, V. W. ; LAUENER, P. A. ; BLESSMANN, G. S.: Prevention of recurrent urinary tract infections with immuno-active E. coli fractions: a meta-analysis of five placebo-controlled double-blind studies.
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Kass 2002 KASS, E. H.: Asymptomatic infections of the urinary tract. 1956.
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Lee, B.; Bhuta, T.; Craig, J. & Simpson, J. Methenamine hippurate for preventing urinary tract infections.
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Krieger 2002 KRIEGER, J. N.: Urinary tract infections: what’s new?
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Nickel 2005a NICKEL, J. C.: Management of urinary tract infections: historical perspective and current strategies: Part 1–Before antibiotics.
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Nickel 2005b NICKEL, J. C.: Management of urinary tract infections: historical perspective and current strategies: Part 2-Modern management.
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Sobel und Vazquez 1999 SOBEL, J. D. ; VAZQUEZ, J. A.: Fungal infections of the urinary tract.
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Sussman und Gally 1999 SUSSMAN, M. ; GALLY, D. L.: The biology of cystitis: host and bacterial factors.
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Tauchnitz 1991 TAUCHNITZ, C: Sepsis.
In: HAHN, H (Hrsg.) ; FALKE, D (Hrsg.) ; KLEIN, P (Hrsg.): Medizinische Mikrobiologie.
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Wagenlehner und Naber 2006 WAGENLEHNER, F. M. ; NABER, K. G.: Treatment of bacterial urinary tract infections: presence and future.
In: Eur Urol
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  Deutsche Version: Therapie der Harnwegsinfektion