Asymptomatic Bacteriuria


Article Author:
Donald Givler


Article Editor:
Amy Givler


Editors In Chief:
Tod Aeby


Managing Editors:
Avais Raja
Orawan Chaigasame
Carrie Smith
Abdul Waheed
Khalid Alsayouri
Kyle Blair
Trevor Nezwek
Radia Jamil
Erin Hughes
Patrick Le
Anoosh Zafar Gondal
Saad Nazir
William Gossman
Hassam Zulfiqar
Navid Mahabadi
Hussain Sajjad
Steve Bhimji
Muhammad Hashmi
John Shell
Matthew Varacallo
Heba Mahdy
Ahmad Malik
Sarosh Vaqar
Mark Pellegrini
James Hughes
Beata Beatty
Daniyal Ameen
Altif Muneeb
Beenish Sohail
Nazia Sadiq
Hajira Basit
Phillip Hynes
Komal Shaheen
Sandeep Sekhon


Updated:
8/22/2019 9:39:12 PM

Introduction

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. While few infants and toddlers have asymptomatic bacteriuria, the incidence increases with age. The incidence is up to 15% or greater in women and men age 65 to 80 years and as high as 40% to 50% after age 80.  Most patients with asymptomatic bacteriuria will never develop symptomatic urinary tract infections and will have no adverse consequences from asymptomatic bacteriuria.  In an age when decreasing unnecessary antibiotic use is emphasized, the important clinical question is this:  Which patients with asymptomatic bacteriuria benefit from treatment? The answer is that most patients with asymptomatic bacteriuria do not benefit from treatment. There are, however, a few exceptions. There is sufficient evidence that a pregnant woman with asymptomatic bacteriuria should be treated.  [1][2][3] Also, patients undergoing urologic procedures in which mucosal bleeding is expected and patients who are in the first three months following renal transplantation should probably be treated for asymptomatic bacteriuria.

Etiology

The etiology of asymptomatic bacteriuria has not been conclusively determined. Asymptomatic bacteriuria is more common among women than among men probably because of the shorter female urethra, which gives bacteria from the urethral meatus and the perineum a shorter distance to the bladder. In fact, most women have transient bacteriuria after sexual intercourse, but few of these women will develop symptomatic infections because the body's normal defense mechanisms prevent symptomatic infection in most cases.  In the elderly, it is thought that incomplete bladder emptying contributes to the increased incidence of asymptomatic bacteriuria.[4]

Epidemiology

Asymptomatic bacteriuria is a common clinical finding. While less than 0.5% of infants and toddlers have asymptomatic bacteriuria, the incidence increases with age. The incidence is 5% or less among healthy premenopausal women, up to 15% or greater in women and men age 65-80 years, and it continues to climb after age 80 to as high as 40% to 50% of long-term care residents. At any age, the incidence of asymptomatic bacteriuria is higher among females than among males. Escherichia coli is the most common bacteria identified in asymptomatic bacteriuria.[5]

History and Physical

Patients with asymptomatic bacteriuria are, by definition, asymptomatic. They have no symptoms that can be attributed to bacteria in the urine. This is completely different from the evaluation and management of symptomatic bacteriuria or urinary tract infections.  Several factors are thought to increase the likelihood of asymptomatic bacteriuria.[6]  These include:

  • obstructive uropathy (stones, prostatic hypertrophy, cystocele, etc.),
  • fecal soiling of the perineum (especially in women),
  • indwelling urinary catheters, and
  • frequent instrumentation of the urinary tract.

Evaluation

Diagnosis of asymptomatic bacteriuria is made by urine culture. Either a properly collected clean-catch specimen or a catheterized specimen is acceptable. The Infectious Diseases Society of America (IDSA) has established criteria for diagnosing asymptomatic bacteriuria.

Midstream clean catch urine specimen:

  • For women, two consecutive specimens with isolation of the same bacteria species with at least 100,000 colony-forming units (CFUs) per ml of urine.
  • For men, a single specimen with isolation of one bacteria species with at least 100,000 CFUs per ml of urine.

Catheterized specimen:

  • For women or men, a single specimen with isolation of one bacteria species with at least 100 CFUs per ml of urine.

Urine dipstick for leukocyte esterase will reliably identify pyuria, but it is not specific for asymptomatic bacteriuria. (Pyuria may result from other inflammatory disorders of the genitourinary tract.) Urinary dipstick for nitrites is also of limited usefulness because of infection with non-nitrite-producing organisms, the delay between collection and testing of the specimen, and insufficient time since the last voiding for nitrites to be produced at detectable levels. The combination of the dipstick for leukocyte esterase and nitrites is more specific for asymptomatic bacteriuria than either test alone. Urinalysis with microscopic exam for bacteria is a useful, but non-quantitative, way to identify bacteriuria.  

Pregnant women should be screened for asymptomatic bacteriuria with a urine culture. The optimal timing and frequency of screening urine cultures in pregnancy have not been established, but obtaining a screening urine culture at the end of the first trimester of pregnancy is recommended.  

Other than in pregnancy, there are few indications to screen for asymptomatic bacteriuria. Two possible clinical scenarios in which a screening urine culture might be appropriate include patients undergoing urological procedures in which mucosal bleeding is expected, such as resection of the prostate, and patients who are in the first three months following renal transplantation.[7]

Treatment / Management

Most patients with asymptomatic bacteriuria will not develop symptomatic urinary tract infections and will have no adverse consequences from asymptomatic bacteriuria.  Specifically, children, patients with diabetes, older patients, patients with spinal cord injuries, and patients with indwelling urinary catheters do not benefit from treatment with antibiotics for asymptomatic bacteriuria. Treatment in these patients does not decrease the incidence of symptomatic urinary tract infections or improve survival. However, it does increase the likelihood of adverse effects from antibiotics and the development of antibiotic-resistant bacteria.

In contrast, treatment of pregnant women with asymptomatic bacteriuria has been shown to be beneficial. Antimicrobial treatment of asymptomatic bacteriuria in pregnancy decreases the risk of pyelonephritis, low-birthweight infants, and preterm delivery.  In addition, patients undergoing urologic procedures in which mucosal bleeding is expected, such as with resection of the prostate, and patients who are in the first three months following renal transplantation probably should be treated. There is evidence that treatment of asymptomatic bacteriuria in these patients decreases the risk of symptomatic urinary tract infection.    

Treatment should be guided by the results of urine culture and sensitivity. Amoxicillin, amoxicillin/clavulanate, cefuroxime, cephalexin, and nitrofurantoin are considered safe for use in pregnancy. [7][8][9] Treatment duration should be for 3 to 7 days for pregnant women, and at least one follow-up urine culture should be performed. 

Pearls and Other Issues

Cost-effective use of health care resources necessitates careful scrutiny to avoid unnecessary tests and treatments.  "Antibiotic stewardship," or the appropriate use of antibiotics in a way that improves patient outcomes, reduces microbial resistance, and decreases the spread of infections caused by multi-drug-resistant organisms, is essential.  As such, a rational and evidence-based approach to the evaluation and treatment of asymptomatic bacteriuria is important.  It is not appropriate to routinely order a urinalysis and urine culture and sensitivity test on every patient admitted to the hospital unless there is a clinical reason to suspect a symptomatic or an occult urinary tract infection. Additionally, when the clean-catch urine culture of a 70-year-old female (who is admitted for a diagnosis unrelated to her urinary tract and has no urinary symptoms) increases to >100,000 CFU/ml of Escherichia coli, which it often will, it is appropriate to resist the temptation to treat the culture results. [10][11] Treatment is unnecessary, and may even be harmful. 

Enhancing Healthcare Team Outcomes

The management of asymptomatic bacteriuria is not simple and requires clinical acumen. When encountering such patients, an interdisciplinary approach with an infectious disease expert, emergency department physician, nurse practitioner, internist, pharmacist, and a nurse is recommended.

Most patients with asymptomatic bacteriuria will not develop symptomatic urinary tract infections and will have no adverse consequences from asymptomatic bacteriuria.  Specifically, children, patients with diabetes, older patients, patients with spinal cord injuries, and patients with indwelling urinary catheters do not benefit from treatment with antibiotics for asymptomatic bacteriuria. Treatment in these patients does not decrease the incidence of symptomatic urinary tract infections or improve survival. However, it does increase the likelihood of adverse effects of antibiotics and the development of antibiotic-resistant bacteria.

In contrast, treatment of pregnant women with asymptomatic bacteriuria has been shown to be beneficial. [12][1]There is evidence that treatment of asymptomatic bacteriuria in these patients decreases the risk of symptomatic urinary tract infection.  

The nurse should focus on assisting with patient education and assisting the family in learning to help the patient. The pharmacist may provide guidance to the clinician regarding medication choices as needed and help prevent drug-drug interactions. The clinical team of pharmacist, nurse, and clinician working together to educate and assist the patient and family will result in the best outcomes. [Level V]


Interested in Participating?

We are looking for contributors to author, edit, and peer review our vast library of review articles and multiple choice questions. In as little as 2-3 hours you can make a significant contribution to your specialty. In return for a small amount of your time, you will receive free access to all content and you will be published as an author or editor in eBooks, apps, online CME/CE activities, and an online Learning Management System for students, teachers, and program directors that allows access to review materials in over 500 specialties.

Improve Content - Become an Author or Editor

This is an academic project designed to provide inexpensive peer-reviewed Apps, eBooks, and very soon an online CME/CE system to help students identify weaknesses and improve knowledge. We would like you to consider being an author or editor. Please click here to learn more. Thank you for you for your interest, the StatPearls Publishing Editorial Team.

Asymptomatic Bacteriuria - Questions

Take a quiz of the questions on this article.

Take Quiz
A 26-year-old G1P0 at 18 weeks grows Escherichia coli on a screening urine specimen. She has no prior history of urinary tract infections and is currently asymptomatic. What is the best treatment for her?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which of the following is true with asymptomatic bacteriuria in pregnancy?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
An asymptomatic 80 year old female has a urine culture showing greater than 100,000 E. coli. What is the appropriate treatment?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which is correct concerning management for asymptomatic pediatric patients with bacteriuria?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
You see the following four patients in the office. Which one should be treated with an antibiotic?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A clean-catch urine culture of an asymptomatic patient grows more than 100,000 colony-forming-units (CFU) per ml of Escherichia coli. Which patient with this culture result should be treated?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
The following patients are seen for routine healthcare. Which one is a candidate for a urine culture to screen for asymptomatic bacteriuria?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Four patients are admitted to the hospital. All had clean-catch urine cultures ordered on admission, and all of the cultures have grown Escherichia coli greater than 100,000 colony-forming-units per mL. None of these patients have urinary symptoms, and none have reason to suspect an occult urinary tract infection. Which patient should be treated for asymptomatic bacteriuria?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
You are providing prenatal care for a 24-year-old pregnant female at 14 weeks gestation. What is the best way to screen her for asymptomatic bacteriuria?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up

Asymptomatic Bacteriuria - References

References

Ditkoff EL,Theofanides M,Aisen CM,Kowalik CG,Cohn JA,Sui W,Rutman M,Adam RA,Dmochowski RR,Cooper KL, Assessment of practices in screening and treating women with bacteriuria. The Canadian journal of urology. 2018 Oct;     [PubMed]
Averbeck MA,Rantell A,Ford A,Kirschner-Hermanns R,Khullar V,Wagg A,Cardozo L, Current controversies in urinary tract infections: ICI-RS 2017. Neurourology and urodynamics. 2018 Jun;     [PubMed]
Wullt B,Sundén F,Grabe M, Asymptomatic Bacteriuria is Harmless and Even Protective: Don't Treat if You Don't Have a Very Specific Reason. European urology focus. 2018 Jul 17;     [PubMed]
Kulchavenya E, Editorial Comment to Role of increasing leukocyturia for detecting the transition from asymptomatic bacteriuria to symptomatic infection in women with recurrent urinary tract infections: A new tool for improving antibiotic stewardship. International journal of urology : official journal of the Japanese Urological Association. 2018 Sep;     [PubMed]
Moore A,Doull M,Grad R,Groulx S,Pottie K,Tonelli M,Courage S,Garcia AJ,Thombs BD, Recommendations on screening for asymptomatic bacteriuria in pregnancy. CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne. 2018 Jul 9;     [PubMed]
Medley N,Vogel JP,Care A,Alfirevic Z, Interventions during pregnancy to prevent preterm birth: an overview of Cochrane systematic reviews. The Cochrane database of systematic reviews. 2018 Nov 14;     [PubMed]
Coussement J,Maggiore U,Manuel O,Scemla A,López-Medrano F,Nagler EV,Aguado JM,Abramowicz D, Diagnosis and management of asymptomatic bacteriuria in kidney transplant recipients: a survey of current practice in Europe. Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association. 2018 Apr 9;     [PubMed]
Bigotte Vieira M,Alves M,Costa J,Vaz-Carneiro A, [Bacteriuria. Cochrane Database Syst Rev. 2015;4:CD009534.] Acta medica portuguesa. 2018 Feb 28;     [PubMed]
Dahiya A,Goldman RD, Management of asymptomatic bacteriuria in children. Canadian family physician Medecin de famille canadien. 2018 Nov;     [PubMed]
Keller SC,Feldman L,Smith J,Pahwa A,Cosgrove SE,Chida N, The Use of Clinical Decision Support in Reducing Diagnosis of and Treatment of Asymptomatic Bacteriuria. Journal of hospital medicine. 2018 Jun 1;     [PubMed]
Albu S,Voidazan S,Bilca D,Badiu M,Truţă A,Ciorea M,Ichim A,Luca D,Moldovan G, Bacteriuria and asymptomatic infection in chronic patients with indwelling urinary catheter: The incidence of ESBL bacteria. Medicine. 2018 Aug;     [PubMed]
Skelton F,Martin LA,Evans CT,Kramer J,Grigoryan L,Richardson P,Kunik ME,Poon IO,Holmes SA,Trautner BW, Determining Best Practices for Management of Bacteriuria in Spinal Cord Injury: Protocol for a Mixed-Methods Study. JMIR research protocols. 2019 Feb 14;     [PubMed]

Disclaimer

The intent of StatPearls is to provide practice questions and explanations to assist you in identifying and resolving knowledge deficits. These questions and explanations are not intended to be a source of the knowledge base of all of medicine, nor is it intended to be a board or certification review of Ob Gyn-Medical Student. The authors or editors do not warrant the information is complete or accurate. The reader is encouraged to verify each answer and explanation in several references. All drug indications and dosages should be verified before administration.

StatPearls offers the most comprehensive database of free multiple-choice questions with explanations and short review chapters ever developed. This system helps physicians, medical students, dentists, nurses, pharmacists, and allied health professionals identify education deficits and learn new concepts. StatPearls is not a board or certification review system for Ob Gyn-Medical Student, it is a learning system that you can use to help improve your knowledge base of medicine for life-long learning. StatPearls will help you identify your weaknesses so that when you are ready to study for a board or certification exam in Ob Gyn-Medical Student, you will already be prepared.

Our content is updated continuously through a multi-step peer review process that will help you be prepared and review for a thorough knowledge of Ob Gyn-Medical Student. When it is time for the Ob Gyn-Medical Student board and certification exam, you will already be ready. Besides online study quizzes, we also publish our peer-reviewed content in eBooks and mobile Apps. We also offer inexpensive CME/CE, so our content can be used to attain education credits while you study Ob Gyn-Medical Student.