Asymptomatic Bacteriuria
No Results
No Results
processing….
Asymptomatic bacteriuria (ABU) is common. The frequency varies among different populations, depending on factors such as age, sex, and underlying disorders (eg, diabetes mellitus or spinal cord injury). [1] One study in hospitalized patients identified obesity and iron deficiency anemia as independent risk factors for ABU. [2]
The frequency of ABU in different populations is as follows:
Preschool girls, <2%
Pregnant women, 2-9.5%
Women aged 65-80 years, 18-43%
Men aged 65-80 years, 1.5-15.3%
Women older than 80 years, 18-43%
Men older than 80 years, 5.4-21%
Patient characteristics also influence the microbiology of ABU. Escherichia coli is the most common organism and is the most likely to occur in healthy persons. A variety of organisms may be found, however, including Enterobacteriaceae, Pseudomonas aeruginosa, Enterococcus species, and group B Streptococcus. In men, Enterococcus species and gram-negative bacilli are common. Catheterized nursing home residents may have polymicrobial ABU. [1]
Laboratory criteria for the diagnosis of ABU in a midstream clean-catch urine specimen are as follows [1] :
For women, 2 consecutive specimens with isolation of at least 100,000 colony-forming units (cfu) per mL of the same bacterial species
For men, a single specimen with isolation of at least 100,000 cfu/mL of a single bacterial species
For the diagnosis of ABU in a catheterized urine specimen, the laboratory criterion is a single bacterial species isolated in a quantitative count of at least 100 cfu/mL. [1] This applies to both women and men.
In most patient populations, treatment of ABU is not clinically beneficial, and consequently, screening for ABU is not recommended. [3] The US Preventive Services Task Force advises against screening men and nonpregnant women for asymptomatic bacteriuria; there is adequate evidence to suggest that screening is ineffective in improving clinical outcomes. [4]
An important exception is pregnant women, for whom ABU carries significant risks and treatment provides important benefits. Antibiotic treatment may also be valuable for children aged 5-6 years and before invasive genitourinary procedures. [5] However, the consensus is that catheterization has no clinical significance and that antibiotic prescription is not indicated in any of the following:
A study by Lin et al suggests the need for greater focus on optimizing the use of antibiotics in patients with enterococcal bacteriuria; overtreatment of ABU is common, especially in patients with pyuria. [6]
Asymptomatic bacteriuria (ABU) is uncommon in the pediatric population (see Table 1 below).
Table 1: Frequency of Asymptomatic Bacteriuria in Pediatric Patients (Open Table in a new window)
Age
Frequency (%)
Female
Male
Infants and toddlers (≤ 36 mo)
0.4-1.8
0.5-2.5
Preschool
0.8-1.3
0.5
School-age children and adolescents
1.1-1.8
~ 0
In premenopausal and nonpregnant women, the frequency of asymptomatic bacteriuria (ABU) is 0.8-5.2%. ABU in this population is associated with more frequent urinary tract infections (UTIs) and subsequent ABU but with no other long-term adverse outcome. Screening for ABU in this population is not recommended, and antibiotic treatment does not reduce the frequency of symptomatic UTI. [7]
The frequency of ABU in healthy young men is essentially zero. Thus, screening for ABU in this population is not recommended.
The frequency of ABU in older adults is as follows:
Age 50-65 years – 2.8-8.6% in women, 0.6-1.5% in men
Age 65-80 years – 5.8-16% in women, 1.5-15.3% in men
Age older than 80 years – 18-43% in women, 5.4-21% in men
Several factors appear to account for the increasing frequency of ABU with advancing age, including the following:
Obstructive uropathy (eg, urinary stones, prostatic hypertrophy, uterine prolapse, or cystocele)
Decreased bactericidal activity in prostatic secretions
Perineal soiling with fecal matter in women with dementia
Neuromuscular disease
Increased instrumentation of the urinary tract
Urinary catheters
Reduced Tamm-Horsfall protein secretion in urine
Increased uropathogens in the postmenopausal vagina and introitus
No morbidity or mortality from ABU has been demonstrated in older adults, though the data are limited; 76% of ABU episodes resolve spontaneously. Screening for ABU is not recommended. Antibiotic treatment does not reduce the frequency of symptomatic UTI or improve survival; instead, it leads to an increased incidence of adverse antibiotic effects and reinfection with antibiotic-resistant organisms. [1]
In older adults with chronic urinary incontinence, ABU can be difficult to differentiate from symptomatic UTI. In such cases, delaying antibiotic treatment for 1 week while offering supportive treatment such as increased fluid intake is an acceptable therapeutic option; up to 50% of women with UTI will have symptom relief or show spontaneous improvement in 1 week without antibiotics. [8]
Among institutionalized adults, the frequency of ABU is 25-53% in women and 19-37% in men. Risk factors include urinary or bowel incontinence and dementia. Screening for ABU in this population is not recommended, and antibiotic treatment does not improve survival or the frequency of symptomatic UTI.
In pregnant women, the frequency of asymptomatic bacteriuria (ABU) in the first trimester is 2-9.5%. Previous urinary tract infection (UTI) or lower socioeconomic status is associated with a higher frequency of ABU.
Older studies found that ABU in pregnancy is significant because 20-30% of untreated cases progress to acute pyelonephritis, usually at the end of the second trimester or early in the third trimester. Acute pyelonephritis in pregnancy is associated with premature labor. Studies of perinatal outcomes in pregnant women with untreated ASB have yielded mixed results, with a number of studies finding an increased risk of premature delivery, lower birth weight, or both, while other studies failed to find an association. [9]
In a 2015 prospective cohort study with an embedded randomized controlled trial in 4283 women with an uncomplicated singleton pregnancy, ABU was not associated with preterm birth; ABU showed a significant association with pyelonephritis, but the absolute risk of pyelonephritis in untreated ABU was low: pyelonephritis developed in 5 of 208 women (2.4%) with untreated or placebo-treated ABU, compared with 24 of 4035 (0.6%) women without ABU (adjusted odds ratio 3.9, 95% confidence index 1.4–11.4).
Nevertheless, because of the dangers posed by ABU in pregnancy, screening for ABU is a standard aspect of prenatal care. The US Preventive Services Task Force recommends screening for asymptomatic bacteriuria with urine culture at 12 to 16 weeks’ gestation or at the first prenatal visit (grade A recommendation). [4]
At least 1 urine culture should be performed at the end of the first trimester; 2 consecutive cultures are preferable because 1-2% of women with a negative initial urine culture develop ABU and experience acute pyelonephritis later in pregnancy. Urine dipstick and microscopic analysis are inadequate for identifying ABU in these patients.
A Cohcrane review concluded that antibiotic treatment in pregnant women with ABU can reduce the risk of pyelonephritis and may reduce risk of low birthweight and preterm birth. However, supporting evidence for those findings was of very low quality. [10]
Guidelines from the Infectious Diseases Society of America recommend 3–7 days of antibiotic therapy for treatment of ABU in pregnancy. [1] A Single-dose regimens have been studied, but may be less effective. [11]
One of the following agents may be used [1] :
Treatment of ABU in pregnancy reduces the frequency of acute pyelonephritis to 2-3%. After treatment of ABU, periodic (eg, monthly) follow-up urine cultures are recommended. (See Urinary Tract Infections in Pregnancy.)
In patients who have spinal cord injury with bladder impairment, the frequency of asymptomatic bacteriuria (ABU) is 70-100%. ABU in these patients is associated with the development of acute pyelonephritis, urosepsis, and renal failure. However, screening for ABU in this population is not recommended, and antibiotic treatment does not improve survival or the frequency of symptomatic urinary tract infections (UTIs).
Patients with spinal cord injury who receive antibiotics for ABU have uniformly showed early recurrence of bacteriuria after therapy. [1] Intermittent urinary catheterization and, in men, sphincterotomy with a condom catheter, producing a low-pressure bladder, significantly reduce morbidity and mortality from UTIs.
Asymptomatic bacteriuria (ABU) is more common in patients of all ages with either type 1 or type 2 diabetes mellitus, compared with patients who do not have diabetes. The increased frequency is probably secondary to autonomic neuropathy of the bladder. Diabetic patients with ABU are more likely to have albuminuria and symptomatic UTIs, but their hemoglobin A1C levels are not significantly higher than those of diabetic patients without ABU. [12]
The frequency of ABU in patients with diabetes mellitus is 7.9-17.7% in females and 1.5-2.2% in males. There is no indication of adverse outcomes in women.
Screening is not recommended, and treatment with antibiotics is not beneficial. A randomized, controlled trial found that treatment of asymptomatic bacteriuria in women with diabetes does not appear to reduce complications. These investigators concluded that diabetes itself should not be an indication for screening for or treatment of ABU. [13]
In renal transplant recipients, asymptomatic bacteriuria (ABU) is principally a concern in the initial months after transplantation: the frequency of ABU is 41% in the first month, 21% in the second month, and 0.01% after 3 months. The risks of ABU in these patients include acute pyelonephritis, sepsis, and graft loss. [14] In 11% of patients, persistent ABU develops and leads to urologic complications.
Screening for ABU is indicated in the immediate postoperative period and for up to 6 months after transplantation. Current practice is to initiate prophylactic antibiotics in the perioperative period and continue them long-term, and to shorten the period of indwelling catheter use. These measures have reduced morbidity to the point that there is no association between ABU and graft loss. Organ donors should be screened and treated in advance for ABU.
Short-term bladder catheterization is associated with a 2-7% frequency of asymptomatic bacteriuria (ABU) for each day that the catheter is in place. The frequency is higher in women than in men. Symptomatic urinary tract infection (UTI) occurs in 26% of women by 14 days after catheter removal.
Screening for ABU is not indicated unless the patient has other risk factors for UTI, however. Antibiotic treatment is possibly beneficial in women with persistent ABU 48 hours after catheter removal. In general, the most effective strategy for reducing the incidence of catheter-related ABU is to reduce catheter use. [15]
ABU is a universal finding in patients with indwelling catheters that have been in place for longer than 30 days. These patients are at risk for acute pyelonephritis, urosepsis, catheter obstruction, renal stones, vesicoureteral reflux, renal failure, and (eventually) bladder cancer.
Unfortunately, treatment of ABU in these patients does not decrease the incidence of fever and usually leads to the development of resistant bacterial strains. In asymptomatic patients with indwelling urethral catheters, cloudy or foul-smelling urine is not an indication for urinalysis, culture, or antimicrobial treatment. [15]
[Guideline] 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 Mar 1. 40(5):643-54. [Medline]. [Full Text].
Cuttitta F, Torres D, Vogiatzis D, Buttà C, Bellanca M, Gueli D, et al. Obesity and iron deficiency anemia as risk factors for asymptomatic bacteriuria. Eur J Intern Med. 2014 Mar. 25(3):292-5. [Medline].
Cai T, Koves B, Johansen TE. Asymptomatic bacteriuria, to screen or not to screen – and when to treat?. Curr Opin Urol. 2017 Mar. 27 (2):107-111. [Medline].
[Guideline] 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 Jul 1. 149(1):43-7. [Medline]. [Full Text].
Raz R. Asymptomatic bacteriuria. Clinical significance and management. Int J Antimicrob Agents. 2003 Oct. 22 Suppl 2:45-7. [Medline].
Lin E, Bhusal Y, Horwitz D, et al. Overtreatment of enterococcal bacteriuria. Arch Intern Med. 2012 Jan 9. 172(1):33-8. [Medline].
Colgan R, Nicolle LE, McGlone A, Hooton TM. Asymptomatic bacteriuria in adults. Am Fam Physician. 2006 Sep 15. 74(6):985-90. [Medline]. [Full Text].
Mody L, Juthani-Mehta M. Urinary tract infections in older women: a clinical review. JAMA. 2014 Feb 26. 311(8):844-54. [Medline]. [Full Text].
Matuszkiewicz-Rowińska J, Małyszko J, Wieliczko M. Urinary tract infections in pregnancy: old and new unresolved diagnostic and therapeutic problems. Arch Med Sci. 2015 Mar 16. 11 (1):67-77. [Medline]. [Full Text].
Smaill FM, Vazquez JC. Antibiotics for asymptomatic bacteriuria in pregnancy. Cochrane Database Syst Rev. 2015 Aug 7. CD000490. [Medline].
Widmer M, Lopez I, Gülmezoglu AM, Mignini L, Roganti A. Duration of treatment for asymptomatic bacteriuria during pregnancy. Cochrane Database Syst Rev. 2015 Nov 11. CD000491. [Medline].
Renko M, Tapanainen P, Tossavainen P, Pokka T, Uhari M. Meta-analysis of the significance of asymptomatic bacteriuria in diabetes. Diabetes Care. 2011 Jan. 34(1):230-5. [Medline]. [Full Text].
Harding GK, Zhanel GG, Nicolle LE, Cheang M. Antimicrobial treatment in diabetic women with asymptomatic bacteriuria. N Engl J Med. 2002 Nov 14. 347(20):1576-83. [Medline].
Yacoub R, Akl NK. Urinary tract infections and asymptomatic bacteriuria in renal transplant recipients. J Glob Infect Dis. 2011 Oct. 3(4):383-9. [Medline]. [Full Text].
[Guideline] Hooton TM, Bradley SF, Cardenas DD, et al. Diagnosis, prevention, and treatment of catheter-associated urinary tract infection in adults: 2009 International Clinical Practice Guidelines from the Infectious Diseases Society of America. Clin Infect Dis. 2010 Mar 1. 50(5):625-63. [Medline]. [Full Text].
Kazemier BM, Koningstein FN, Schneeberger C, Ott A, Bossuyt PM, de Miranda E, et al. Maternal and neonatal consequences of treated and untreated asymptomatic bacteriuria in pregnancy: a prospective cohort study with an embedded randomised controlled trial. Lancet Infect Dis. 2015 Nov. 15 (11):1324-33. [Medline].
Age
Frequency (%)
Female
Male
Infants and toddlers (≤ 36 mo)
0.4-1.8
0.5-2.5
Preschool
0.8-1.3
0.5
School-age children and adolescents
1.1-1.8
~ 0
Edgar V Lerma, MD, FACP, FASN, FAHA, FASH, FNLA, FNKF Clinical Professor of Medicine, Section of Nephrology, Department of Medicine, University of Illinois at Chicago College of Medicine; Research Director, Internal Medicine Training Program, Advocate Christ Medical Center; Consulting Staff, Associates in Nephrology, SC
Edgar V Lerma, MD, FACP, FASN, FAHA, FASH, FNLA, FNKF is a member of the following medical societies: American Heart Association, American Medical Association, American Society of Hypertension, American Society of Nephrology, Chicago Medical Society, Illinois State Medical Society, National Kidney Foundation, Society of General Internal Medicine
Disclosure: Author for: UpToDate, ACP Smart Medicine, Elsevier, McGraw-Hill, Wolters Kluwer.
Vecihi Batuman, MD, FASN Huberwald Professor of Medicine, Section of Nephrology-Hypertension, Tulane University School of Medicine; Chief, Renal Section, Southeast Louisiana Veterans Health Care System
Vecihi Batuman, MD, FASN is a member of the following medical societies: American College of Physicians, American Society of Hypertension, American Society of Nephrology, International Society of Nephrology, Southern Society for Clinical Investigation
Disclosure: Nothing to disclose.
Amy J Behrman, MD Associate Professor, Department of Emergency Medicine, Director, Division of Occupational Medicine, Perelman School of Medicine at the University of Pennsylvania
Amy J Behrman, MD is a member of the following medical societies: American College of Occupational and Environmental Medicine, American College of Physicians
Disclosure: Serve(d) as a director, officer, partner, employee, advisor, consultant or trustee for: Consultant for Sanofi, Influenza Vaccine Branch.
Judith Green-McKenzie, MD, MPH, FACP, FACOEM Associate Professor, Director of Clinical Practice, Occupational Medicine Residency Director, University of Pennsylvania School of Medicine
Judith Green-McKenzie, MD, MPH, FACP, FACOEM is a member of the following medical societies: American College of Physicians, American College of Preventive Medicine, National Medical Association, American College of Occupational and Environmental Medicine
Disclosure: Nothing to disclose.
William H Shoff, MD, DTM&H Former Director, PENN Travel Medicine; Former Associate Professor, Department of Emergency Medicine, Hospital of the University of Pennsylvania, University of Pennsylvania School of Medicine
William H Shoff, MD, DTM&H is a member of the following medical societies: American College of Physicians, American Society of Tropical Medicine and Hygiene, International Society of Travel Medicine, Society for Academic Emergency Medicine, Wilderness Medical Society
Disclosure: Nothing to disclose.
Christopher Edwards, MD Assistant Professor of Clinical Emergency Medicine, Department of Emergency Medicine, Penn Presbyterian Medical Center, Perelman School of Medicine, University of Pennsylvania
Christopher Edwards, MD is a member of the following medical societies: American College of Emergency Physicians, Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.
Eleanor Lederer, MD Professor of Medicine, Chief, Nephrology Division, Director, Nephrology Training Program, Director, Metabolic Stone Clinic, Kidney Disease Program, University of Louisville School of Medicine; Consulting Staff, Louisville Veterans Affairs Hospital
Eleanor Lederer, MD is a member of the following medical societies: American Association for the Advancement of Science, American Federation for Medical Research, American Society for Biochemistry and Molecular Biology, American Society for Bone and Mineral Research, American Society of Nephrology, American Society of Transplantation, International Society of Nephrology, Kentucky Medical Association, National Kidney Foundation, and Phi Beta Kappa
Disclosure: Dept of Veterans Affairs Grant/research funds Research
Chike Magnus Nzerue, MD Associate Dean for Clinical Affairs, Vice-Chairman of Internal Medicine, Meharry Medical College
Chike Magnus Nzerue, MD is a member of the following medical societies: American Association for the Advancement of Science, American College of Physicians, American College of Physicians-American Society of Internal Medicine, American Society of Nephrology, and National Kidney Foundation
Disclosure: Nothing to disclose.
Suzanne Moore Shepherd, MD, MS, DTM&H, FACEP, FAAEM Associate Professor, Education Officer, Department of Emergency Medicine, Hospital of the University of Pennsylvania; Director of Education and Research, PENN Travel Medicine
Suzanne Moore Shepherd, MD, MS, DTM&H, FACEP, FAAEM is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American Society of Tropical Medicine and Hygiene, International Society of Travel Medicine, Society for Academic Emergency Medicine, and Wilderness Medical Society
Disclosure: Nothing to disclose.
Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference
Disclosure: Medscape Salary Employment
Asymptomatic Bacteriuria
Research & References of Asymptomatic Bacteriuria|A&C Accounting And Tax Services
Source