The role of asymptomatic bacteriuria in young women with recurrent urinary tract infections: to treat or not to treat?

Clin Infect Dis. 2012 Sep;55(6):771-7.

Cai T, Mazzoli S, Mondaini N, Meacci F, Nesi G, D’Elia C, Malossini G, Boddi V, Bartoletti R.



Little is known about the role of asymptomatic bacteriuria (AB) treatment in young women affected by recurrent urinary tract infection (UTI). We aimed to evaluate the impact of AB treatment on the recurrence rate among young women affected by recurrent UTI. A total of 673 consecutive asymptomatic young women with demonstrated bacteriuria from January 2005 to December 2009 were prospectively enrolled. Patients were split into 2 groups: not treated (group A, n = 312) and treated (group B, n = 361). Microbiological and clinical evaluations were performed at 3, 6, and 12 months. Quality of life was also measured. Recurrence-free rate at the end of the entire study period was the main outcome measure. At baseline, the 2 most commonly isolated pathogens were Escherichia coli (group A, 38.4%; group B, 39.3%) and Enterococcus faecalis (group A, 32.7%; group B, 33.2%). At the first follow-up visit, there was no difference between the 2 groups (relative risk [RR], 1.05; 95% confidence interval [CI], 1.01-1.10), whereas after 6 months, 23 (7.6%) in group A and 98 (29.7%) in group B showed recurrence with a statistically significant difference (RR, 1.31; 95% CI, 1.21-1.42; P < .0001). At the last follow-up, 41 (13.1%) in group A and 169 (46.8%) in group B showed recurrence (RR, 3.17; 95% CI, 2.55-3.90; P < .0001). One patient in group A and 2 patients in group B were found to have pyelonephritis. This study shows that AB should not be treated in young women affected by UTI, suggesting it may play a protective role in preventing symptomatic recurrence.

PMID:22677710 DOI: 10.1093/cid/cis534



Asymptomatic bacteriuria (ABU), defined as the presence of bacteria in the urine of an individual without signs or symptoms of a urinary tract infection, is generally present in 3% to 5% of young healthy women and is more common in patients with diabetes and elderly persons1,2. Initially, it was assumed to be a strong relationship between bacteriuria and pyelonephritis because the ABU has been previously frequently found in subjects with high prevalence of pyelonephritis episodes3. However, several randomized clinical studies consistently documented that the treatment of bacteriuria in asymptomatic patients does not provide any benefit for the patient in term of risk of recurrence 4,5. Despite these merging evidences, ABU is often treated by repeated antibiotic treatment cycles without significant results and occasionally induces the development of selection of multidrug resistant bacteria6. In particular  recurrent UTI in premenopausal young sexually active women are often treated by repeated cycles of empirical antibiotic therapy, thus inducing asymptomatic short periods of wellness and sterile urine but followed by other episodes of asymptomatic bacteriuria7. Cai et al. recently investigated the impact of antibiotic treatment on recurrence rate of young women affected by recurrent UTI and asymptomatic bacteriuria 7. They demonstrated that 7.6% of non-treated but 29.7% of treated patients showed new infections with a statistically significant difference in terms of recurrence rate after 6 months (RR, 1.31; 95% CI, 1.21-1.42; P <.0001). Moreover, at 12 months follow-up, 13.1% of treated and 46.8% of untreated subjects showed infection recurrence respectively (RR, 3.17; 95% CI, 2.55-3.90; P <.0001) 7. Furthermore, the same study highlighted that the majority of   patients who were recurrence free were found to have ABU caused by E. faecalis at the second and third follow-up evaluations. This may lead to the question whether specific strains of E. faecalis, able to adhere to the bladder mucosa but not virulent enough to produce symptomatic UTI, may be even better suited for study of bacterial interference than E. coli strains3. The results of this study provided a clear answer: the antibiotic treatment of ABU in young women with recurrent UTI is not only unnecessary, but harmful. In the specific case ABU should be considered as a generally benign and sometimes even protective condition. Not to treat ABU in general (except during pregnancy and before invasive intervention of the urinary tract), and especially not in young women with recurrent UTI, is highly recommended and should become the standard of care7. Unnecessary laboratory and clinical investigations currently used in the diagnosis of ABU and antibiotic consumption could be easily avoided by inducing not only a sensible money saving  but also a relevant reduction of either the antimicrobial selection pressure in the community or the emergence of antibiotic resistance in everyday clinical practice3. Recently,  Beerepoot et al. reported a prevalence of 23.7% and 28.1% asymptomatic bacteriuria from E. faecalis and E. coli respectively, in a group of pre-menopausal women affected by recurrent urinary tract infections8. Moreover, they demonstrated increased resistance rates for trimethoprim, amoxicillin, and ciprofloxacin in these E. coli isolates after 1 month in the trimethoprim/sulfamethoxazole group, but not in the control group, highlighting the risk of  emergence of antibiotic resistance in case of ABU treatment due to ecological disturbances in the normal intestinal microflora by promoting the emergence of antimicrobial-resistant strains9. Herr et al. demonstrated that antibacterial therapy before outpatient flexible cystoscopy does not appear necessary in bladder tumor patients who have no clinical signs or symptoms of acute UTI, including ABU, underlining that antibiotic stewardship is the responsibility of all urologists11. On the other hand, despite ample evidence for, and broad consensus on, the futility of antibiotic therapy for ABU in patients with indwelling catheter, physicians tend to prescribe antibiotics for ASB because of lack of knowledge and misconceptions12. The ABU treatment in patients with indwelling catheter and antibiotics used for UTIs (quinolones, third-generation cephalosporins, trimethoprim-sulfamethoxazole) are risk factors for infection with, and carriage of, Enterobacteriaceae producing extended-spectrum beta-lactamase (ESBL), an increasing concern in European hospitals12. The case for non-treatment of catheter-associated bacteriuria is particularly strong in persons who require long-term indwelling urinary catheters, because nearly all such individuals are infected with multiple species13. Moreover, avoidance of unnecessary antibiotic use in the hospital setting is particularly relevant given the current epidemic of nosocomially acquired Clostridium difficile colitis14. Biofilm formation plays an important role in the field of urology, due to its development on the inner and outer surfaces of indwelling urinary catheters and ureteral stents. This phenomenon may be the reason for perpetuation the bacterial presence in the urinary tract15-16; considering that resistance to antibiotics is increasing, there is a growing need to develop and test novel alternative strategies to reduce catheter bacterial colonization17-18. In conclusion, we would like to remember to all that Clinical Infectious Diseases journal published a call for national performance measures to encourage non-treatment of asymptomatic bacteriuria19. This goal has been reaffirmed by the US Preventive Services Task Force in a recent publication stating that men and non-pregnant women should not be screened for asymptomatic bacteriuria20. Moreover, the ESIU board members highlighted that increasing antibiotic resistance and lack of new antibiotics in the near future calls for a variety of coordinated strategies called “Antibiotic stewardship”, to improve antibiotic use with the goal of enhancing patient health outcomes and reducing emergence of resistance to antibiotics21. In particular, the urologic community can fight resistance development by ensuring the appropriate use of antibiotic prophylaxis and treatment by following the European Association of Urology guidelines22, insisting on there being regular local surveillance of isolates from both community and hospital episodes of UTI.



1. Hooton TM, Scholes D, Stapleton AE, Roberts PL, Winter C, Gupta K, Samadpour M, Stamm WE. A prospective study of asymptomatic bacteriuria in sexually active young women. N Engl J Med. 2000;343(14):992-7.

2. Raz R. Asymptomatic bacteriuria: clinical significance and management. Int J Antimicrob Agents 2003;22(Suppl. 2):45–47.

3. Wagenlehner FME and Naber KG. Editorial Commentary: Asymptomatic Bacteriuria—Shift of Paradigm. Clin Infect Dis. (2012) 55 (6): 778-780.

4. 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. Clin Infect Dis 2005;40:643-54.

5. Beerepoot MA, den Heijer CD, Penders J., Prins JM, Stobberingh EE, Geerlings SE: Predictive value of Escherichia coli susceptibility in strains causing asymptomatic bacteriuria for women with recurrent symptomatic urinary tract infections receiving prophylaxis. Clin. Microbiol. Infct. 2012; 18:E84-90

5. French GL. The continuing crisis in antibiotic resistance. Int J Antimicrob Agents. 2010;36 Suppl 3:S3-7.

6. Cai T, Mazzoli S, Mondaini N, Meacci F, Nesi G, dÉlia C, Malossini G, Boddi V, Bartoletti R The Role of Asymptomatic Bacteriuria in Young Women With Recurrent Urinary Tract Infections: To Treat or Not to Treat?” – Clin Infect Dis. (2012) 55 (6): 771-777.

7. Beerepoot MA, Ter Riet G, Nys S, van der Wal WM, de Borgie CA, de Reijke TM, Prins JM, Koeijers J, Verbon A, Stobberingh E, Geerlings SE. Cranberries vs Antibiotics to Prevent Urinary Tract Infections: A Randomized Double-blind Noninferiority Trial in Premenopausal Women. Arch Intern Med. 2011;171(14):1270-8.

8. Edlund C, Nord CE. Effect on the human normal microflora of oral antibiotics for treatment of urinary tract infections. J Antimicrob Chemother. 2000;46 Suppl 1:41-8; discussion 63-5.

9. Herr HW. Should Antibiotics Be Given Prior to Outpatient Cystoscopy? A Plea to Urologists to Practice Antibiotic Stewardship. Eur Urol. 2013 doi: 10.1016/j.eururo.2013.08.054.

10. Egger M, Balmer F, Friedli-Wüthrich H, Mühlemann K. Reduction of urinary catheter use and prescription of antibiotics for asymptomatic bacteriuria in hospitalised patients in internal medicine. Swiss Med Wkly. 2013;143:w13796.

11. Pfaller MA, Segreti J. Overview of the epidemiological profile and laboratory detection of

extended-spectrum beta-lactamases. Clin Infect Dis. 2006;42:S143–53.

12. Warren J, Tenney J, Hoopes J, Muncle H, Anthony W. A prospective microbiologic study of bacteriuria in patients with chronic indwelling urethral catheters. J Infect Dis 1982; 146:719–23.

13. Aslam S, Musher DM. An update on diagnosis, treatment, and prevention of Clostridium difficile–associated disease. Gastroenterol Clin North Am 2006; 35:315–35.

14. Pickard R, Lam T, Maclennan G, Starr K, Kilonzo M, McPherson G, Gillies K, McDonald A, Walton K, Buckley B, Glazener C, Boachie C, Burr J, Norrie J, Vale L, Grant A, N’dow J. Types of urethral catheter for reducing symptomatic urinary tract infections in hospitalised adults requiring short-term catheterisation: multicentre randomised controlled trial and economic evaluation of antimicrobial- and antiseptic-impregnated urethral catheters (the CATHETER trial). Health Technol Assess. 2012;16(47):1-197.

15. Pickard R, Lam T, MacLennan G, Starr K, Kilonzo M, McPherson G, Gillies K, McDonald A, Walton K, Buckley B, Glazener C, Boachie C, Burr J, Norrie J, Vale L, Grant A, N’Dow J. Antimicrobial catheters for reduction of symptomatic urinary tract infection in adults requiring short-term catheterisation in hospital: a multicentre randomised controlled trial. Lancet 2012; 380(9857):1927-35.

16. Hachem R, Reitzel R, Borne A, et al. (2009) Novel antiseptic urinary catheters for prevention of urinary tract infections: correlation of in vivo and in vitro test results. Antimicrob Agents Chemother 53(12): 5145-9.

17. Cai T, Caola I, Tessarolo F, Piccoli F, D’Elia C, Caciagli P, Nollo G, Malossini G, Nesi G, Mazzoli S, Bartoletti R. Solidago, Orthosiphon, Birch and cranberry extracts can decrease microbial colonization and biofilm development in indewelling urinary catheter: a microbiological and ultrastructural pilot study. Worl Journal of Urology 2013, in press; 10.1007/s00345-013-1173-5.

18. Gross PA, Patel B. Reducing antibiotic overuse: a call for a national performance measure for not treating asymptomatic bacteriuria. Clin Infect Dis 2007; 45:1335–7.

19. U.S. Preventive Services Task Force. Screening for asymptomatic bacteriuria in adults: U.S. Preventive Services Task Force reaffirmation recommendation statement. Ann Intern Med 2008; 149:43–7.

20. Wagenlehner FM, Bartoletti R, Cek M, Grabe M, Kahlmeter G, Pickard R, Bjerklund-Johansen TE. Antibiotic stewardship: a call for action by the urologic community. Eur Urol. 2013;64(3):358-60.

21. Grabe M, Bjerklund-Johansen TE, Botto H, et al. Guidelines on urological infections. European Association of Urology Web site. Updated 2012.



Tommaso Cai, MD

Dept. of Urology

Santa Chiara Regional Hospital

Largo  Medaglie d’Oro, 9

38123 – Trento, Italy

Tommaso Cai-1


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