KAUTII
Articles
- Page Path
- HOME > Urogenit Tract Infect > Volume 20(2); 2025 > Article
- Review Article Asymptomatic Bacteriuria in Older Adults – Diagnosis, Management, and Future Directions: A Narrative Review
-
Ki Hong Kim
, Hee Jo Yang -
Urogenital Tract Infection 2025;20(2):58-66.
DOI: https://doi.org/10.14777/uti.2550002001
Published online: August 31, 2025
Department of Urology, Soonchunhyang University Cheonan Hospital, Cheonan, Korea JFIF d d Ducky d qhttp://ns.adobe.com/xap/1.0/ |er˭|I|-fGK.rΛp8XV1%K6mvG+tc+qE &ǸC_Nm:l=_/m5^[dߌڇ.c<%:)tQ$Ow~-aY;UJ >=F)2[nk؆?훐 M=l6[4(O.]2#-H^n#->&mp5~Fӛ+|| S,xag% qkEUzUgæBhߕP(7]kFnq?֖Cpru Z6*rEڊtS|*tI*E}7R<,nUU֫^I7Q*mSly%rdȓd8hE<9oHhMfNSRj[i7D[Rj݊+kდq{"$$H?p \̅S?㭻;t~ R߁ )^/>Qj`yt[w ԛ;² ~+ ߔ_ YW~|o] ?x^ᯛ `ʼn;g)T@vWn]>&4l p+$D̢1l|ȨF%-} .9[}w~
ԠLM9hСablfe&QoW !s ?wjLK?s7yO>(=C~_nyǜu? v 3vyo oI@qV-jeES^[9WoSܝh"l2C1a͔CiJ@3:Pճw= /7ovuk+\V;lDgն <[A+r X~d;m!_s8ݖ;;.0llUC+?i#_crʙ1~C.\q u l8Hܶ2m`ܻM3Tov|Bs rɵ"oLS-
DКw=Tv@f '6|YlD͓Y%-#Ѯo%:&!3o%\J<02;K87>^vgƓ# ;ݝmz^Y6=PS39U%~
&f#
}o!muH; ʲŇ˷yvP+&.7e[3'vR4Yj̗IZ`e˽3o[WU{
m[sUbۋZǾۆl6~9'V*.\S2<Sd*zY[aŶ`]C$n.v^Ʌ
dng>ەZ,Mmϑ :n6nϦezW qUJ4! ۇ4R! =>>F n|Q[{pRO 17ƕ~._I ''00k=b՛o}Osðc2'o\3}ݭQ^ 2 . R1yKȣtAݿ-u ܾw!`?1Whn|gzU o[ECWwjUIן)^h#1ɭ!/Z
np;o;ΗŻkXs."6E`Z1
עӐ9Kl8qd q} 2Stt;#j>;խabONŗ=fwP1j)l6J̶|gV 2`y/0E˛6+ԫ1?
6}KW c\KoKͨ2ۅFws*TԞLיuDx .kCzWXhy۶gLu|%TnupǺl-S* P RaLnT+c+*xl.v!.U=|; !_L̎뱚U=4hm:ٯ"y)$:>%(n}X'p[ȴ
^˒4kƓmzDx
\
'Nq amP7nyN݅=
-
Corresponding author: Hee Jo Yang Department of Urology, Soonchunhyang University Cheonan Hospital, 44, Suncheonhyang 4-gil, Dongnam-gu, Cheonan 31151, Korea Email: c78154@schmc.ac.kr
• Received: June 10, 2025 • Revised: June 27, 2025 • Accepted: July 23, 2025
Copyright © Korean Association of Urogenital Tract Infection and Inflammation
This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
- 8,435 Views
- 69 Download
- 1 Crossref
Abstract
- Asymptomatic bacteriuria (ASB) is defined as the presence of bacteria in the urine in the absence of urinary tract infection (UTI) symptoms. The prevalence of ASB increases with advancing age, particularly among older patients with underlying health conditions. ASB is especially common among residents of long-term care facilities; however, distinguishing ASB from symptomatic UTI in this population remains a significant clinical challenge. The frequent occurrence of ASB often results in unnecessary antibiotic administration, thereby contributing to the development of antibiotic resistance. Current clinical guidelines recommend screening for and treating ASB only in certain circumstances, such as prior to urological procedures or in pregnant women. There is a pressing need for improved diagnostic approaches to differentiate ASB more accurately from UTI, particularly in older adults. Reducing unnecessary urine testing and inappropriate antibiotic use may help prevent over-treatment and minimize associated risks, including Clostridium difficile infection and increased antimicrobial resistance.
HIGHLIGHTS
Asymptomatic bacteriuria (ASB) is common among elderly individuals, particularly those in long-term care facilities. Despite its high prevalence, ASB typically does not harm health without needing treatment except in specific cases such as prior to urological procedures. Misdiagnosis of ASB as urinary tract infection (UTI) often leads to unnecessary antibiotic use known to contribute to resistance and cause adverse effects. Differentiating ASB from UTI is challenging due to overlapping nonspecific symptoms in elderly patients. Improved diagnostic tools, including biomarkers and molecular methods, are needed to guide treatment decisions, reduce antibiotic misuse, and enhance patient outcomes.
INTRODUCTION
Asymptomatic bacteriuria (ASB) is defined as the presence of bacteria in the urine without urinary symptoms [1]. ASB is commonly observed and considered a form of commensal colonization, potentially playing a protective role against development of symptomatic urinary tract infection (UTI) [2]. Unlike ASB, UTIs are diagnosed when urinary symptoms are accompanied by bacteriuria or when symptoms are nonspecific with the same bacteria cultured from both urine and blood samples. ASB has a high prevalence in elderly patients with positive urine cultures but nonspecific symptoms, makes diagnosing UTIs challenging [1,3,4].
ASB occurs in 3%–5% of young and healthy women. Its prevalence is 0.7%–27% in patients with diabetes and 4%–19% in the elderly [5,6]. Antibiotic treatment for ASB should be used sparingly because it can increase the rate of antibiotic resistance. Several clinical guidelines recommend screening and treating ASB only in specific cases, such as for prophylactic purposes before urological procedures or in pregnant women. For most ASB cases, treatment is not advised [1,2,7].
ASB is common in the elderly, primarily due to physiological changes associated with aging (e.g., altered bactericidal activity of prostatic secretions, decreased estrogen levels) and comorbidities [8]. To date, negative effects of ASB have not been demonstrated. ASB is known to have no impact on survival [8]. Treatment of ASB is not recommended in the elderly, with growing evidence suggesting that ASB might play a protective role against UTIs [6,9,10]. This is particularly challenging in residents of long-term care facilities (LTCFs) where ambiguous symptom reporting makes UTI diagnosis difficult, often leading to excessive antibiotic use. Such antibiotic use ultimately contributes to increased rates of antibiotic resistance. Here we summarize current evidence on ASB to reduce unnecessary diagnosis and treatment of ASB.
DIAGNOSIS
ASB is defined as the presence of at least 10⁵ colony forming unit (CFU)/mL of the same uropathogenic bacteria in 2 consecutive midstream urine samples from an asymptomatic individual [1]. For urine specimens obtained through intermittent catheterization, ASB is defined as the presence of bacteria at concentrations of at least 10² CFU/mL [11]. The diagnosis of UTIs in community-dwelling elderly individuals requires significant bacteriuria (≥10⁵ CFU/mL) accompanied by urinary symptoms, as in younger adults [1].
Diagnosing UTIs in the elderly can be challenging because their symptoms are often nonspecific. In a study of patients aged 65 years or older who visited the emergency department, 47% of patients with UTIs did not report urinary symptoms [12]. In another study, 18 out of 37 patients with bacteremic UTI aged 75 years or older did not have urinary symptoms [13]. In 26 elderly patients with bacteremic UTI, their main symptoms were confusion (30%), cough (27%), and dyspnea (28%), with new urinary symptoms appearing in 20% [13]. Nonspecific symptoms that may appear in acute UTI in the elderly include fever, syncope, weakness, delirium, foul-smelling urine, and changes in blood glucose levels [14-17]. However, these symptoms are also commonly observed in elderly individuals, making it unreliable to predict positive urine culture results based on these symptoms alone [18]. To distinguish UTIs from ASB, it is important to investigate nonurinary causes of fever and other nonspecific symptoms.
Diagnosing UTIs can be challenging even in elderly individuals with intact cognitive function. Distinguishing ASB from UTIs in elderly people with cognitive impairment is even more challenging [4]. Particularly among residents of LTCFs, multiple comorbidities can present symptoms similar to those of UTIs, further complicating diagnosis. In cases of cognitive impairment, there may be no complaints about any symptoms related to UTIs [19,20].
To address these diagnostic challenges, McGeer et al. have suggested diagnostic criteria for UTI according to recommendations of the Infectious Diseases Consensus Group with criteria being different depending on whether the individual has an indwelling catheter or not (Table 1) [21].
PREVALENCE
The prevalence of ASB increases with age. Among young women, the prevalence of ASB is 1%–2%, rising to 6%–16% in women aged 65–90 years and 22%–43% in women over 90 years old [3]. ASB is very rare in young men. However, its prevalence increases to 5%–21% in men aged 65 years and older, with the highest prevalence observed in those over 90 years old [3,6,22]. Among elderly residents of LTCFs, 25%–50% of women and 15%–35% of men have ASB, with a higher prevalence in individuals having severe disabilities [15,22]. Nearly 100% of elderly individuals with long-term indwelling catheters have ASB [4]. However, in patients with only nonspecific symptoms without distinct urinary symptoms, the prevalence of ASB may vary depending on how UTIs are defined (Fig. 1).
PATHOPHYSIOLOGY
The etiology of ASB in the elderly is multifactorial. Risk factors for ASB include anatomical abnormalities of the urinary tract (e.g., benign prostatic hyperplasia), hormonal and metabolic changes (e.g., decreased estrogen, diabetes), neurological disorders, and poor perianal hygiene, similar to those for UTIs [23]. ASB is particularly common among residents of LTCFs, the causes of ASB are comparable to that of UTIs. Differences in the occurrence of ASB by gender are largely due to anatomical and physiological changes, as is the case with UTIs Several factors contribute to the high frequency of UTIs among elderly residents in LTCFs; however, the relative significance of these factors varies between individuals. Similar to UTIs, age-related physiological changes, comorbidities that reduce immune response, such as diabetes, and interventions for managing voiding are the most important contributing factors. Notably, in institutionalized elderly individuals, neurogenic bladder-related complications are likely to have the greatest impact [15]. Many degenerative neurological diseases are commonly associated with neurogenic bladder, which can increase the risk of infection through mechanisms such as voiding dysfunction, elevated post-micturition residual urine volume, and vesico-ureteral reflux. Additionally, prior catheterization or the use of urinary devices further influences the likelihood of developing bacteriuria [15]. However, Escherichia coli is less frequently the causative pathogen compared to other causes of UTIs [23]. Elderly patients often have smaller bladder capacities, leading to frequent urination. Additionally, low fluid intake can result in concentrated, foul-smelling urine, making it difficult to distinguish between ASB and symptomatic UTIs [24].
The occurrence of bacteriuria varies depending on both host and microorganism characteristics. In most healthy adults, acute bacteriuria does not progress to persistent bacteriuria. Hooton et al. [25] have prospectively evaluated the occurrence of ASB in 796 sexually active women aged 18–40 years. They found that fewer than 1% of those with ASB developed persistent bacteriuria [25]. Additionally, persistent bacteriuria caused by the same strain is rare. Long-term bacteriuria caused by E. coli often has an attenuated virulence phenotype [26]. This supports the hypothesis that loss or disruption of virulence gene expression can facilitate long-term colonization and adaptation to the host environment.
Host characteristics can also affect the occurrence of bacteriuria. Differences in innate immune responses based on genetic background are also important. Decreased TLR4 expression and diminished innate immune responses are being associated with ASB [27]. Treatment of ASB can eliminate bacteriuria and reduce the occurrence of UTIs. However, there is a high likelihood of recolonization by the same or similar bacteria [28].
EVALUATION
To diagnose ASB, UTI must be excluded. Urinalysis is usually performed prior to deciding on empirical antibiotic treatment for UTIs. The prevalence of pyuria without bacteriuria is high in elderly individuals. Thus, the presence of pyuria alone is not helpful for diagnosing UTIs. While dipstick tests are generally accurate and sensitive, one study has shown that 96.9% of elderly patients with bacteremic UTIs are positive by dipstick test and approximately 90% of patients with isolated bacteriuria also have a positive dipstick result [29,30]. However, a meta-analysis estimated that the sensitivity for detecting UTIs in the elderly was only 82% [31]. Although nitrite test is more specific than leukocyte esterase, it has a lower sensitivity. Therefore, it cannot be used alone to exclude UTIs [29]. Microscopic urinalysis is also inaccurate, as 21.9% of patients with bacteremic UTIs have fewer than 10 leukocytes per high-power field in their urine samples [29].
Recently, Advani et al. [32] have proposed new criteria for ASB. In addition to the 3 phenotypes conventionally classified (no UTI, ASB, and UTIs), 2 new categories, lower urinary tract symptoms/other urologic symptoms and bacteriuria of unclear significance (BUS) are added. They have suggested that the existing 3 phenotypes do not sufficiently reflect clinical manifestations of patients. BUS is defined as cases 1 clinical criterion with or without other cause or cannot express symptoms (might have urologic criteria without clinical criteria). The conventional definition of ASB per the established criteria continues to mean that ASB has no specific signs or symptoms of a UTI or any clinical criteria (Fig. 2) [32]. Through a retrospective analysis, Advani et al. [32] have confirmed that there are differences in patient characteristics according to this new classification system, demonstrating the effectiveness of the new classification system. However, the extent to which treatment is needed has not been investigated yet.
MANAGEMENT
Antibiotics are commonly used in the elderly with fever and other nonspecific symptoms. Since UTIs are among common causes of fever, urine cultures and antibiotic treatment are often administered regardless of urinary symptoms. Inappropriate treatment of ASB confirmed by urine cultures occurs frequently not only in the United States but also in Canada and Europe. According to a recent meta-analysis study, the rate of inappropriate treatment for ASB was 45% in the United States, 58% in Canada, and 47% in Europe [33]. The American Geriatrics Society has listed unnecessary antibiotic use for ASB as one of the 5 most overused medical services [33].
There have been reports indicating that the length of hospitalization for ASB patients is longer due to inappropriate treatment of ASB [34,35]. Antibiotic treatment for ASB can increase the risk of antibiotic-associated diarrhea, including Clostridium difficile infections, as well as the risk of antimicrobial resistance [36]. A recent study has reported that E. coli detected in ASB patients shows greater antibiotic resistance than E. coli isolated from UTI patients, although the number of patients is small [37]. Ultimately, the uncertainty in distinguishing between ASB and UTI may partially explain the "overtreatment" of ASB patients.
In the elderly, routine screening and treatment for ASB are not recommended. Screening or treatment for ASB is not recommended either women with diabetes, elderly individuals residing in the community or institutionalized settings, patients with spinal cord injury, or those with indwelling catheters [1]. However, screening and treatment for ASB in the elderly are recommended in 2 specific situations based on randomized trial results: prior to transurethral resection of the prostate and before urological procedures where mucosal injury is anticipated (Table 2) [1].
Strategies to reduce treatment of ASB include minimizing unnecessary urine culture to reduce overdiagnosis, mitigating ASB occurrence through immunomodulation, and reducing inappropriate antimicrobial use through appropriate antimicrobial stewardship programs [9].
UTIs are common causes of fever, leading to routine urine culture tests in elderly patients with fever, regardless the presence of urinary symptoms. It is clear that elderly patients presenting with urinary symptoms or signs attributable to urological causes should undergo urine testing. However, to reduce the proportion of unnecessary urine tests in acutely ill elderly patients, prescribing practices by physicians need changes. One recommended strategy is to refrain from automatically reporting urine culture results and perform urine cultures only when it is absolutely necessary and upon request [38]. Another approach involves automatically canceling urine cultures when urinalysis results are negative. For instance, if dipstick testing, microscopic urinalysis, or urinalysis shows negative results, then urine culture should be canceled. It have been shown that canceling urine culture orders for elderly patients with negative dipstick tests reduce inappropriate antibiotic treatments without compromising patient safety [29,30].
The use of probiotics or immunomodulating agents has also been proposed as a method to reduce the incidence of UTIs. Krebs et al. [39] have administered a lyophilized lysate of 18 E. coli strains to patients with spinal cord injuries for over 12 months and found that it can significantly decrease the incidence of recurrent UTIs and notably increase the proportion of patients who have remained UTI-free. A meta-analysis reported in 2013 evaluated the therapeutic effects of Lactobacillus for recurrent UTIs [40]. Recurrent UTIs were significantly reduced in patients who received Lactobacillus, with an odds ratio of 0.51. Lactobacillus helps to create an acidic environment by producing lactic acid and other acids. Vaginal Lactobacillus protects the female urogenital tract from colonization by pathogens, so it can contribute to the prevention of urogenital infections [41]. Although, while these interventions appear effective in reducing UTI incidence, further studies are needed to determine their roles in decreasing the occurrence of ASB.
To reduce treatment of ASB, it has been recommended to monitor stable patients without urinary symptoms, signs, or fever for 48 hours without antibiotics [4,42]. A key challenge is to determine which elderly patients with nonspecific symptoms or signs can be observed without treatment instead of receiving empirical antibiotic treatment at presentation. Most experts recommend initiating antibiotic therapy for elderly patients with fever (generally defined as body temperature ≥38°C). In contrast, stable, afebrile patients without localized urinary symptoms or signs may be considered for observation. There are 3 management strategies to reduce unnecessary urinalysis as shown below [43].
(1) Determine whether the patient’s symptoms have an extraurinary source.
(2) Patients with clear extraurinary symptoms should not undergo urinalysis or urine culture.
(3) For patients without extraurinary causes of symptoms: (a) Urinalysis may be performed as needed, but additional reflex microscopic examination should be avoided. (b) If the dipstick test is negative, urine cultures should be canceled. (c) Classify patients as stable or unstable: (i) Stable patients without fever: Closely monitor for 48 hours without antibiotics. Perform urinalysis only if needed and perform urine culture only if the dipstick test is positive. Treat with empirical antibiotics if symptoms worsen or persist, and investigate other potential causes or diagnoses. (ii) Unstable patients: treat with appropriate antibiotics.
However, some studies have compared the effectiveness of expert-led education programs aimed at improving inappropriate antimicrobial treatment of ASB and indicated that such interventions fail to bring about sustained changes in ASB management [44]. This highlights the need for a more systematic solution to address the issue [44].
FUTURE DIRECTIONS
In the elderly, ASB is often treated inappropriately with antibiotics even though it does not require treatment. This is because the diagnosis of UTIs in the elderly is often ambiguous. Therefore, there is a need for improved diagnostic tests to differentiate ASB from UTIs in the elderly [45]. Some studies have utilized the analysis of inflammatory cytokine levels in urine to distinguish ASB from upper UTIs. Kjölvmark et al. [46] have compared urinary heparin-binding protein and urinary interleukin-6 (IL-6) in LTCF residents, finding that both levels are significantly lower in ASB patients than in those with UTIs. Additionally, Sundén and Wullt [47] have compared urinary IL-6 and IL-8 levels in patients with ASB and UT and found that both urinary IL-6 and IL-8 levels are low in ASB patients with only IL-6 showing a significant increase during UTI episodes. The use of novel biomarkers may aid in distinguishing ASB. The risk of severe infection and the need for treatment in ASB can be predicted based on bacterial virulence factors. For example, several virulence factors of E. coli are associated with pyelonephritis [48]. Therefore, rapid molecular diagnostic tests to detect the presence and pathogenic potential of E. coli could be helpful in determining whether to administer antibiotics.
CONCLUSIONS
Although ASB is commonly observed in vulnerable populations, such as the elderly, ASB is not known to have a negative impact on health. The distinction between ASB and UTIs is often ambiguous, leading to frequent inappropriate antibiotic use, which can result in serious issues such as antibiotic resistance. Treating ASB is not recommended except in specific cases, such as prior to urological procedures or during pregnancy.
To clearly distinguish ASB from UTIs in elderly patients, clinicians must adopt a symptom-based approach and carefully evaluate urine test results. Development of new classification systems, inflammatory biomarkers, and molecular diagnostic tools can aid in distinguishing ASB from UTIs, reduce unnecessary antibiotic use and improve patient safety.
-
Funding/Support
This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
-
Conflict of Interest
The authors have nothing to disclose.
-
Author Contribution
Conceptualization, KHK and HJY; Methodology, HJY.; Software, HJY; Validation, HJY.; Formal Analysis, KHK; Investigation, KHK and HJY; Resources, KHK.; Data Curation, HJY; Writing - Original Draft Preparation, KHK and HJY; Writing - Review & Editing, KHK and HJY; Visualization, KHK; Supervision, HJY; Project Administration, KHK and HYJ; Funding Acquisition, none.
NOTES
Fig. 1.
Prevalence of asymptomatic bacteriuria in the elderly. (adopted from Luu and Albarillo [22]), LTCF, long-term care facilities; DM, diabetes mellitus.
Fig. 2.
Diagnostic approach of ASB. (A) Ideal diagnostic approach algorithm. (B) Diagnostic approach starting from urine culture and concept of continuum of UTI. ASB, asymptomatic bacteriuria; UTI, urinary tract infection; CFU/HPE, colony forming unit/high power field; LCC, low colony count positive urine culture with <100,000 CFU/mL; BUS, bacteriuria of unclear significance.
Table 1.
Diagnostic recommendations for urinary tract infection in the elderly
Table 2.
Recommendations for asymptomatic bacteriuria (ASB) in the elderly
- 1. Nicolle LE, Gupta K, Bradley SF, Colgan R, DeMuri GP, Drekonja D, et al. Clinical practice guideline for the management of asymptomatic bacteriuria: 2019 update by the Infectious Diseases Society of America. Clin Infect Dis 2019;68:e83-110.ArticlePubMedPDF
- 2. Kranz J, Bartoletti R, Bruyère F, Cai T, Geerlings S, Köves B, et al. European Association of Urology guidelines on urological infections: summary of the 2024 guidelines. Eur Urol 2024;86:27-41.PubMed
- 3. Nicolle LE. Asymptomatic bacteriuria in the elderly. Infect Dis Clin North Am 1997;11:647-62.ArticlePubMed
- 4. Cortes-Penfield NW, Trautner BW, Jump RL. Urinary tract infection and asymptomatic bacteriuria in older adults. Infect Dis Clin North Am 2017;31:673-88.ArticlePubMedPMC
- 5. Lee MJ, Kim M, Kim NH, Kim CJ, Song KH, Choe PG, et al. Why is asymptomatic bacteriuria overtreated?: a tertiary care institutional survey of resident physicians. BMC Infect Dis 2015;15:289.ArticlePubMedPMCPDF
- 6. Cai T, Koves B, Johansen TE. Asymptomatic bacteriuria, to screen or not to screen - and when to treat? Curr Opin Urol 2017;27:107-11.ArticlePubMed
- 7. French GL. The continuing crisis in antibiotic resistance. Int J Antimicrob Agents 2010;36 Suppl 3:S3-7.ArticlePubMed
- 8. Ipe DS, Sundac L, Benjamin WH Jr, Moore KH, Ulett GC. Asymptomatic bacteriuria: prevalence rates of causal microorganisms, etiology of infection in different patient populations, and recent advances in molecular detection. FEMS Microbiol Lett 2013;346:1-10.ArticlePubMed
- 9. Köves B, Cai T, Veeratterapillay R, Pickard R, Seisen T, Lam TB, et al. Benefits and harms of treatment of asymptomatic bacteriuria: a systematic review and meta-analysis by the European Association of Urology Urological Infection Guidelines Panel. Eur Urol 2017;72:865-8.PubMed
- 10. Cai T, Mazzoli S, Mondaini N, Meacci F, Nesi G, D'Elia C, et al. The role of asymptomatic bacteriuria in young women with recurrent urinary tract infections: to treat or not to treat? Clin Infect Dis 2012;55:771-7.ArticlePubMed
- 11. Hooton TM, Bradley SF, Cardenas DD, Colgan R, Geerlings SE, Rice JC, 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;50:625-63.ArticlePubMedPDF
- 12. Caterino JM, Kline DM, Leininger R, Southerland LT, Carpenter CR, Baugh CW, et al. Nonspecific symptoms lack diagnostic accuracy for infection in older patients in the Emergency Department. J Am Geriatr Soc 2019;67:484-92.ArticlePubMedPMCPDF
- 13. Barkham TM, Martin FC, Eykyn SJ. Delay in the diagnosis of bacteraemic urinary tract infection in elderly patients. Age Ageing 1996;25:130-2.ArticlePubMed
- 14. Mody L, Juthani-Mehta M. Urinary tract infections in older women: a clinical review. JAMA 2014;311:844-54.ArticlePubMedPMC
- 15. Nicolle LE. Urinary tract infections in long-term-care facilities. Infect Control Hosp Epidemiol 2001;22:167-75.ArticlePubMed
- 16. Juthani-Mehta M, Quagliarello V, Perrelli E, Towle V, Van Ness PH, Tinetti M. Clinical features to identify urinary tract infection in nursing home residents: a cohort study. J Am Geriatr Soc 2009;57:963-70.ArticlePubMedPMC
- 17. Balogun SA, Philbrick JT. Delirium, a symptom of UTI in the elderly: fact or fable? A systematic review. Can Geriatr J 2014;17:22-6.ArticlePubMedPMCPDF
- 18. Sundvall PD, Ulleryd P, Gunnarsson RK. Urine culture doubtful in determining etiology of diffuse symptoms among elderly individuals: a cross-sectional study of 32 nursing homes. BMC Fam Pract 2011;12:36.ArticlePubMedPMCPDF
- 19. Yoshikawa TT, Nicolle LE, Norman DC. Management of complicated urinary tract infection in older patients. J Am Geriatr Soc 1996;44:1235-41.ArticlePubMed
- 20. Rodriguez-Mañas L. Urinary tract infections in the elderly: a review of disease characteristics and current treatment options. Drugs Context 2020;9:2020-4-13.
- 21. McGeer A, Campbell B, Emori TG, Hierholzer WJ, Jackson MM, Nicolle LE, et al. Definitions of infection for surveillance in long-term care facilities. Am J Infect Control 1991;19:1-7.ArticlePubMed
- 22. Luu T, Albarillo FS. Asymptomatic bacteriuria: prevalence, diagnosis, management, and current antimicrobial stewardship implementations. Am J Med 2022;135:e236-44.ArticlePubMed
- 23. Wagenlehner FM, Naber KG, Weidner W. Asymptomatic bacteriuria in elderly patients: significance and implications for treatment. Drugs Aging 2005;22:801-7.PubMed
- 24. van Duin D. Diagnostic challenges and opportunities in older adults with infectious diseases. Clin Infect Dis 2012;54:973-8.ArticlePubMedPMC
- 25. Hooton TM, Scholes D, Stapleton AE, Roberts PL, Winter C, Gupta K, et al. A prospective study of asymptomatic bacteriuria in sexually active young women. N Engl J Med 2000;343:992-7.ArticlePubMed
- 26. Salvador E, Wagenlehner F, Köhler CD, Mellmann A, Hacker J, Svanborg C, et al. Comparison of asymptomatic bacteriuria Escherichia coli isolates from healthy individuals versus those from hospital patients shows that long-term bladder colonization selects for attenuated virulence phenotypes. Infect Immun 2012;80:668-78.ArticlePubMedPMCPDF
- 27. Ulett GC, Totsika M, Schaale K, Carey AJ, Sweet MJ, Schembri MA. Uropathogenic Escherichia coli virulence and innate immune responses during urinary tract infection. Curr Opin Microbiol 2013;16:100-7.ArticlePubMed
- 28. Dalal S, Nicolle L, Marrs CF, Zhang L, Harding G, Foxman B. Long-term Escherichia coli asymptomatic bacteriuria among women with diabetes mellitus. Clin Infect Dis 2009;49:491-7.ArticlePubMedPMC
- 29. Shimoni Z, Glick J, Hermush V, Froom P. Sensitivity of the dipstick in detecting bacteremic urinary tract infections in elderly hospitalized patients. PLoS One 2017;12:e0187381.ArticlePubMedPMC
- 30. Shimoni Z, Hermush V, Glick J, Froom P. No need for a urine culture in elderly hospitalized patients with a negative dipstick test result. Eur J Clin Microbiol Infect Dis 2018;37:1459-64.ArticlePubMedPDF
- 31. Devillé WL, Yzermans JC, van Duijn NP, Bezemer PD, van der Windt DA, Bouter LM. The urine dipstick test useful to rule out infections. a meta-analysis of the accuracy. BMC Urol 2004;4:4.PubMedPMC
- 32. Advani SD, Turner NA, North R, Moehring RW, Vaughn VM, Scales CD Jr, et al. Proposing the "continuum of UTI" for a nuanced approach to diagnosis and management of urinary tract infections. J Urol 2024;211:690-8.ArticlePubMedPMC
- 33. Flokas ME, Andreatos N, Alevizakos M, Kalbasi A, Onur P, Mylonakis E. Inappropriate management of asymptomatic patients with positive urine cultures: a systematic review and meta-analysis. Open Forum Infect Dis 2017;4:ofx207.ArticlePubMedPMCPDF
- 34. Horstman MJ, Spiegelman AM, Naik AD, Trautner BW. Urine culture on admission impacts antibiotic use and length of stay: a retrospective cohort study. Infect Control Hosp Epidemiol 2018;39:547-54.ArticlePubMed
- 35. Petty LA, Vaughn VM, Flanders SA, Malani AN, Conlon A, Kaye KS, et al. Risk factors and outcomes associated with treatment of asymptomatic bacteriuria in hospitalized patients. JAMA Intern Med 2019;179:1519-27.ArticlePubMedPMC
- 36. Leffler DA, Lamont JT. Clostridium difficile infection. N Engl J Med 2015;372:1539-48.ArticlePubMed
- 37. Leihof RF, Nielsen KL; Frimodt-Møller N. Asymptomatic bacteriuria (ABU) in elderly: prevalence, virulence, phylogeny, antibiotic resistance and complement C3 in urine. Microorganisms 2021;9:390.ArticlePubMedPMC
- 38. Leis JA, Rebick GW, Daneman N, Gold WL, Poutanen SM, Lo P, et al. Reducing antimicrobial therapy for asymptomatic bacteriuria among noncatheterized inpatients: a proof-of-concept study. Clin Infect Dis 2014;58:980-3.ArticlePubMed
- 39. Krebs J, Fleischli S, Stoyanov J, Pannek J. Effects of oral immunomodulation therapy on urinary tract infections in individuals with chronic spinal cord injury-A retrospective cohort study. Neurourol Urodyn 2019;38:346-52.ArticlePubMedPDF
- 40. Grin PM, Kowalewska PM, Alhazzan W, Fox-Robichaud AE. Lactobacillus for preventing recurrent urinary tract infections in women: meta-analysis. Can J Urol 2013;20:6607-14.PubMed
- 41. Reid G, Burton J. Use of Lactobacillus to prevent infection by pathogenic bacteria. Microbes Infect 2002;4:319-24.ArticlePubMed
- 42. Beveridge LA, Davey PG, Phillips G, McMurdo ME. Optimal management of urinary tract infections in older people. Clin Interv Aging 2011;6:173-80.ArticlePubMedPMC
- 43. Shimoni Z, Cohen R, Froom P. Prevalence, impact, and management strategies for asymptomatic bacteriuria in the acute care elderly patient: a review of the current literature. Expert Rev Anti Infect Ther 2020;18:453-60.ArticlePubMed
- 44. Hong C, Egan G, Sherk B. Burning for treatment: impact of staff education on asymptomatic bacteriuria management in the elderly. Can Geriatr J 2020;23:257-63.ArticlePubMedPMCPDF
- 45. Biggel M, Heytens S, Latour K, Bruyndonckx R, Goossens H, Moons P. Asymptomatic bacteriuria in older adults: the most fragile women are prone to long-term colonization. BMC Geriatr 2019;19:170.ArticlePubMedPMCPDF
- 46. Kjölvmark C, Tschernij E, Öberg J, Påhlman LI, Linder A, Åkesson P. Distinguishing asymptomatic bacteriuria from urinary tract infection in the elderly - the use of urine levels of heparin-binding protein and interleukin-6. Diagn Microbiol Infect Dis 2016;85:243-8.ArticlePubMed
- 47. Sundén F, Wullt B. Predictive value of urinary interleukin-6 for symptomatic urinary tract infections in a nursing home population. Int J Urol 2016;23:168-74.ArticlePubMed
- 48. Johnson JR, Kuskowski MA, Gajewski A, Soto S, Horcajada JP, Jimenez de Anta MT, et al. Extended virulence genotypes and phylogenetic background of Escherichia coli isolates from patients with cystitis, pyelonephritis, or prostatitis. J Infect Dis 2005;191:46-50.ArticlePubMed
REFERENCES
Figure & Data
REFERENCES
Citations
Citations to this article as recorded by 
- Editorial for Urogenital Tract Infection (UTI) 2025 Vol. 20 No. 2 – Highlights of This Issue’s Papers and the UTI Editors’ Pick
Koo Han Yoo
Urogenital Tract Infection.2025; 20(2): 55. CrossRef
Cite
XML DownloadAsymptomatic Bacteriuria in Older Adults – Diagnosis, Management, and Future Directions: A Narrative Review
Fig. 1. Prevalence of asymptomatic bacteriuria in the elderly. (adopted from Luu and Albarillo [22]), LTCF, long-term care facilities; DM, diabetes mellitus.
Fig. 2. Diagnostic approach of ASB. (A) Ideal diagnostic approach algorithm. (B) Diagnostic approach starting from urine culture and concept of continuum of UTI. ASB, asymptomatic bacteriuria; UTI, urinary tract infection; CFU/HPE, colony forming unit/high power field; LCC, low colony count positive urine culture with <100,000 CFU/mL; BUS, bacteriuria of unclear significance.
Fig. 1.
Fig. 2.
Asymptomatic Bacteriuria in Older Adults – Diagnosis, Management, and Future Directions: A Narrative Review
| If there is no indwelling catheterization (3 or more of the following): |
| • Fever of 38°C or higher |
| • New onset or worsened frequency or urgency or dysuria |
| • New flank pain or suprapubic tenderness |
| • Changes in urine characteristics |
| • Worsening of mental or functional status |
| If there is indwelling catheterization (2 or more of the following): |
| • Fever of 38°C or higher |
| • New flank pain or suprapubic tenderness |
| • Changes in urine characteristics |
| • Worsening of mental or functional status |
| Screening and Treating ASB in the elderly are needed under the following situation: |
| • Prior to transurethral resection of the prostate |
| • Before urological surgeries where mucosal bleeding is anticipated |
| Screening and treating ASB in the elderly are not recommended under the following situation: |
| • Women with diabetes |
| • Elderly individuals residing in the community or institutionalized |
| • Patients with spinal cord injuries |
| • Patients with indwelling catheters |
Table 1. Diagnostic recommendations for urinary tract infection in the elderly
Table 2. Recommendations for asymptomatic bacteriuria (ASB) in the elderly
