Asymptomatic bacteriuria: review and discussion of the IDSA guidelines

Abstract

Asymptomatic bacteriuria is a common finding, but is usually benign. Screening and treatment of asymptomatic bacteriuria is only recommended for pregnant women, or for patients prior to selected invasive genitourinary procedures. Healthy women identified with asymptomatic bacteriuria on population screening subsequently experience more frequent episodes of symptomatic infection, but antimicrobial treatment of asymptomatic bacteriuria does not decrease the occurrence of these episodes. Clinical trials in spinal-cord injury patients, diabetic women, patients with indwelling urethral catheters, and elderly nursing home residents have consistently found no benefits with treatment of asymptomatic bacteriuria. Negative outcomes with antimicrobial treatment do occur, including adverse drug effects and re-infection with organisms of increasing resistance. Optimal management of asymptomatic bacteriuria requires appropriate implementation of screening strategies to promote timely identification of the selected patients for whom treatment is beneficial, and avoidance of antimicrobial therapy where no benefit has been shown.

Introduction

Asymptomatic bacteriuria, also referred to as asymptomatic urinary tract infection (UTI), is common [1]. There has been considerable controversy about the appropriate management of bacteriuria. Evidence reported in clinical trials undertaken over the past three decades, however, is sufficient to support recommendations for management in most populations. The optimal approach varies among different patient groups. Recently, the Infectious Diseases Society of America (IDSA) developed and published guidelines for screening for, and the treatment of, asymptomatic bacteriuria [2]. This paper provides a commentary on these guidelines, including a review of important recommendations.

The IDSA uses a standard rating system to describe the strength of recommendation and level of evidence. For strength of recommendation, ‘A’ means the recommendation is always valid; ‘B’ that it is valid in most cases, but there may be exceptions; and ‘C’ that it may or may not be appropriate. The quality of evidence is judged by Roman numerals, ‘I’ for at least one prospective randomized comparative trial—the highest quality of evidence; ‘II’ for prospective cohort studies, or case-control studies; and ‘III’ for consensus of experts in the absence of appropriate clinical trials.