Asymptomatic Bacteriuria is a Complicated Disease in Pregnant Women

Asymptomatic bacteriuria is the presence of bacteria in the properly collected urine of a patient that has no signs or symptoms of a urinary tract infection. Asymptomatic bacteriuria is very common in clinical practice and its incidence increases with age. The incidence is 15 percent or greater in women and men age 65 to 80 years and as high as 40 to 50 percent after age 80. Most patients with asymptomatic bacteriuria will never develop symptomatic urinary tract infections and will have no adverse consequences from asymptomatic bacteriuria. Only patients with asymptomatic bacteriuria that will benefit from treatment should be treated, and most patients will not benefit from treatment.

Asymptomatic bacteriuria is very common, and is usually benign. An individual may have transient bacteriuria of any duration, or bacteriuria may persist for days to years with the same or differing organisms. Resolution of bacteriuria may occur spontaneously or as a consequence of antimicrobial therapy given for any indication. Recurrent bacteriuria is frequent. Bacteriuria has been associated with harmful outcomes in a few well-characterized populations, for whom screening and treatment of bacteriuria prevents adverse outcomes. On the other hand, antimicrobial therapy prescribed inappropriately to the many individuals with asymptomatic bacteriuria who are not at risk for adverse outcomes contributes to antimicrobial pressure, which promotes the development of antimicrobial resistance. In addition, asymptomatic bacteriuria appears to prevent development of symptomatic urinary tract infection for some populations. This observation has stimulated exploration of the potential therapeutic benefit of establishing asymptomatic bacteruria with an avirulent strain to prevent recurrent symptomatic infection, referred to as bacterial interference.