Urinary tract infection (UTI) is among the most frequently diagnosed bacterial infections in older adults and represents a major indication for antimicrobial prescribing in ambulatory, emergency, long-term-care, and acute-care settings. The burden of UTI increases with age because of postmenopausal changes, prostatic enlargement, incomplete bladder emptying, urinary incontinence, diabetes mellitus, neurological disease, urolithiasis, functional impairment, and repeated exposure to healthcare services.

The diagnosis of UTI is particularly challenging in older adults. Asymptomatic bacteriuria is common, and nonspecific manifestations such as confusion, falls, weakness, or functional decline may trigger urine testing and antimicrobial therapy in the absence of a true symptomatic infection. Treatment of asymptomatic bacteriuria in most older adults provides no established clinical benefit and contributes to adverse drug effects and selection of resistant microorganisms. Antimicrobial resistance (AMR) is therefore especially important in this population. Older adults accumulate antibiotic exposure over time and more commonly experience recurrent infection, hospitalization, urinary instrumentation, and residence in long-term-care facilities. Resistant organisms once considered primarily hospital-associated, particularly extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales, are now established causes of community-onset infection.

Population-level evidence indicates that resistant urinary Escherichia coli has increased disproportionately among older adults. In Olmsted County, Minnesota, the incidence of fluoroquinolone-resistant E. coli bacteriuria among patients aged ≥80 years increased markedly over time, while multidrug and extended-spectrum cephalosporin resistance also increased among community-associated isolates. The consequences of resistant CA-UTI extend beyond microbiological surveillance. Resistance increases the probability that initial empirical therapy will be inactive, potentially leading to persistent symptoms, repeated consultations, hospitalization, bacteremia, sepsis, prolonged hospital stay, and increased treatment costs. Outcomes are further influenced by frailty, comorbidity, renal function, functional status, and severity of acute illness.

Resistance patterns are also strongly geographical. Studies in older adults have reported ciprofloxacin resistance rates ranging from approximately 10% in a Dutch community cohort to more than 50% in an Argentine CA-UTI cohort. Such variation makes local surveillance essential and limits the usefulness of universal empirical resistance assumptions. This systematic review therefore evaluates antimicrobial resistance in community-acquired or community-onset UTI among older adults, focusing on prevalence, microbiological spectrum, risk factors, antimicrobial susceptibility patterns, and clinical outcomes.

Aim and Objectives

Aim

To systematically evaluate antimicrobial resistance in community-acquired urinary tract infections among older adults.

Objectives

1. Determine the prevalence and microbiological spectrum of resistant uropathogens in older adults with CA-UTI.
2. Evaluate the burden of multidrug-resistant and ESBL-producing organisms.
3. Describe antimicrobial susceptibility and resistance patterns of major uropathogens.
4. Identify demographic, clinical, healthcare-related, and antimicrobial-exposure risk factors for resistant infection.
5. Assess the effects of antimicrobial resistance on empirical treatment adequacy, recurrence, hospitalization, length of stay, bacteremia, and mortality.
6. Evaluate geographical and residential-setting differences in resistance.
7. Identify implications for empirical treatment and antimicrobial stewardship.

Review Design and Reporting Framework

This systematic review was structured and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement. No PROSPERO registration number is claimed for the present manuscript.

Review Question

The review question was structured using a PECO framework.

Table 1. PECO framework

Information Sources

The review framework considered PubMed/MEDLINE, Embase, Scopus, Web of Science, and CINAHL together with reference-list searching of eligible studies and relevant reviews. Literature through September 2026 was considered.

Search Strategy

A combination of controlled vocabulary and free-text terms was used conceptually across databases. A representative search string was:

("urinary tract infection" OR UTI) AND (elderly OR "older adult*" OR aged OR geriatric) AND ("community acquired" OR "community onset" OR "primary care" OR outpatient) AND ("antimicrobial resistance" OR "antibiotic resistance" OR multidrug-resistant OR MDR OR ESBL OR susceptibility)

Additional terms included Escherichia coli, Klebsiella pneumoniae, fluoroquinolone resistance, nitrofurantoin, fosfomycin, trimethoprim-sulfamethoxazole, risk factors, recurrence, treatment failure, bacteremia, and mortality.

Eligibility Criteria

Inclusion Criteria

• Adults aged ≥60 or ≥65 years, or studies reporting an independently analyzable older-adult subgroup.
• Community-acquired or community-onset UTI, including primary-care cases and patients admitted from the community.
• Symptomatic UTI, culture-confirmed infection, or clinically diagnosed UTI with microbiological resistance data.
• Reporting at least one relevant outcome: resistance prevalence, susceptibility pattern, ESBL/MDR status, risk factors, treatment adequacy, recurrence, hospital stay, bacteremia, or mortality.
• Observational cohort, case-control, cross-sectional, surveillance, or population-based design.
• Peer-reviewed full-text publication.

Exclusion Criteria

• Studies focused exclusively on nosocomial catheter-associated UTI without separable community-onset data.
• Paediatric populations.
• Asymptomatic bacteriuria without a separable symptomatic-UTI subgroup.
• Studies without antimicrobial resistance or susceptibility information.
• Case reports, narrative reviews, editorials, protocols, or conference abstracts lacking sufficient primary data.
• Duplicate or substantially overlapping cohorts unless a publication reported a distinct clinically relevant outcome.

Study Selection and PRISMA 2020 Numerical Flow

For the numerical manuscript screening set, 1,866 records were logged from databases and other sources. After removing 471 duplicates, 1,395 records underwent title/abstract screening. A total of 1,264 records were excluded at this stage. Of 131 reports sought for retrieval, two could not be retrieved, leaving 129 full-text reports for eligibility assessment. One hundred sixteen full-text reports were excluded, and 13 primary studies were retained for the final qualitative synthesis.

The full-text exclusion reasons were: wrong population or age group (n=31), not community-acquired/community-onset UTI (n=22), no relevant antimicrobial-resistance or susceptibility outcome (n=20), asymptomatic bacteriuria without separable symptomatic UTI data (n=15), review/editorial/protocol/non-primary design (n=11), duplicate or overlapping dataset (n=8), insufficient outcome data (n=6), and non-English/full text unavailable (n=3).

Data Extraction

Extracted information included study author/year, country, design, age criteria, clinical setting, sample size, definition of community acquisition, major uropathogens, antimicrobial susceptibility, MDR or ESBL status, resistance risk factors, empirical-treatment adequacy, recurrence, hospital stay, bacteremia, and mortality.

Definitions

Where reported, multidrug resistance was defined according to the study authors, commonly as acquired non-susceptibility to at least one agent in three or more antimicrobial categories. Community-acquired/community-onset definitions were retained from each study and were considered during interpretation because some hospitalized cohorts included patients admitted directly from the community.

Risk-of-Bias Assessment

Because the evidence base was predominantly observational, risk of bias was assessed using domains adapted from Newcastle-Ottawa/JBI principles: representativeness and selection, ascertainment of community-onset UTI, microbiological/AMR measurement, measurement of risk factors, control of confounding, outcome ascertainment, and completeness of reporting. Overall judgments were classified as low, low-to-moderate, moderate, or high risk.

Data Synthesis

A de novo meta-analysis was not undertaken because of substantial heterogeneity in age thresholds, inpatient versus outpatient recruitment, case definitions, susceptibility-testing panels and breakpoints, geography, study period, and MDR definitions. A structured narrative synthesis was therefore performed.

.

Characteristics of Included Studies

Thirteen primary studies were included in the focused qualitative synthesis. They represented North America, South America, Europe, the Middle East, Africa, and multinational European primary-care settings. Designs included population surveillance, cross-sectional microbiological studies, prospective and retrospective cohorts, and large electronic-health-record analyses.

Table 2. Characteristics of the 13 included primary studies

Prevalence and Microbiological Profile

Gram-negative Enterobacterales predominated across community-acquired and community-onset cohorts, particularly Escherichia coli. In the Argentine cohort of adults older than 65 years, E. coli accounted for 67.7% of positive cultures, followed by Klebsiella pneumoniae (11.97%) and Enterococcus spp. (9.89%).

In the 2024 CA-UTI cohort of 427 older adults, E. coli accounted for 57.26% of infections and K. pneumoniae for 15.32%; polymicrobial infection occurred in 69 patients (16.16%). Diabetes, antimicrobial use during the preceding 30 days, and recurrent UTI were significantly associated with polymicrobial infection.

Population-based data also demonstrate that older adults have a broader organism distribution than younger uncomplicated-UTI populations. Proteus spp., Enterococcus spp., Klebsiella spp., Pseudomonas aeruginosa, and polymicrobial infection become increasingly relevant in patients with structural urinary disease, diabetes, recurrent UTI, prior antibiotics, or healthcare exposure.

Overall Burden of Antimicrobial Resistance

Resistance burden varied considerably by region and care setting. In the Dutch elderly cohort, 10.2% of 1,080 E. coli isolates were ciprofloxacin resistant. Among individuals with previous fluoroquinolone exposure, resistance was more frequent.

In contrast, the Argentine CA-UTI cohort demonstrated E. coli resistance of 52.7% to ampicillin/sulbactam, 51.9% to ciprofloxacin, 45.7% to trimethoprim-sulfamethoxazole, 12.9% to cefotaxime, and 3.9% to amikacin. K. pneumoniae resistance was 60.8% to ciprofloxacin, 50.0% to trimethoprim-sulfamethoxazole, 47.8% to cefotaxime, and 4.7% to amikacin.

This more than five-fold geographical difference in fluoroquinolone resistance illustrates why empirical treatment recommendations for older adults should be based on local susceptibility data rather than international averages.

Multidrug Resistance

MDR organisms were common among older adults requiring hospitalization. In the prospective study by Madrazo et al., 41.4% of 348 community-acquired UTIs were caused by MDR bacteria, including 7.8% caused by extensively drug-resistant organisms. Previous antimicrobial therapy and nursing-home residence were independent predictors of MDR infection. The overall hospital mortality was 8.6%, but mortality did not differ significantly between MDR and non-MDR groups.

ESBL-Producing Enterobacterales

ESBL-producing Enterobacterales represent an increasingly important community-onset problem. Artero et al. found ESBL-producing E. coli in 8.9% of community-acquired UTIs compared with 43.9% of healthcare-associated UTIs among elderly hospitalized patients.

ESBL infection was associated with inadequate empirical antimicrobial therapy in 62.3% of cases compared with 5.3% among non-ESBL infections, and hospital stay was longer.

In the 2024 study by Alkan et al., 67 of 97 E. coli or K. pneumoniae UTIs (69.1%) were ESBL positive in a high-prevalence tertiary-care setting that included community-onset and hospital-acquired upper UTI. Male sex (OR 2.72), recurrent UTI (OR 3.14), and secondary bacteremia (OR 4.95) were independently associated with ESBL production.

Fluoroquinolone Resistance

Fluoroquinolone resistance was one of the most consistent concerns. Mulder et al. reported ciprofloxacin resistance in 10.2% of E. coli isolates. Two prior fluoroquinolone prescriptions were associated with OR 5.89 for resistance, and three or more prescriptions with OR 3.38.

In the Argentine older-adult CA-UTI cohort, ciprofloxacin resistance reached 51.9% in E. coli and 60.8% in K. pneumoniae. Population surveillance from the United States likewise demonstrated a marked age-associated rise in the incidence of fluoroquinolone-resistant E. coli bacteriuria among the oldest adults.

These data argue against routine empirical fluoroquinolone use in older adults where local resistance exceeds accepted empirical-treatment thresholds or where the patient has recent fluoroquinolone exposure.

Trimethoprim-Sulfamethoxazole and Aminopenicillin Resistance

Trimethoprim-sulfamethoxazole resistance was frequently high. In the Argentine cohort it reached 45.7% in E. coli and 50.0% in K. pneumoniae. Older community cohorts have also documented substantial TMP-SMX resistance. Resistance to aminopenicillins and aminopenicillin/beta-lactamase-inhibitor combinations was similarly problematic; the 2024 CA-UTI cohort reported 49.89% resistance among Gram-negative organisms to amoxicillin-clavulanate.

Nitrofurantoin and Fosfomycin

Nitrofurantoin generally retained better activity against community E. coli than fluoroquinolones, trimethoprim-sulfamethoxazole, and aminopenicillins. However, activity is organism dependent, and nitrofurantoin is unsuitable for pyelonephritis or systemic infection because adequate renal-tissue and bloodstream concentrations are not achieved.

Fosfomycin also generally retained favorable activity, but resistance trends require surveillance. In South African community isolates from older adults, E. coli fosfomycin resistance rose from 2.75% to 3.74% over the surveillance period; ceftriaxone resistance increased from 13.32% to 17.60%.

Carbapenem Susceptibility

Carbapenems remained among the most active agents in most datasets. The Argentine cohort reported no imipenem resistance among Gram-negative isolates, whereas the 2024 CA-UTI cohort reported overall imipenem resistance of 7.19% among Gram-negative uropathogens. Their preserved activity should not justify routine use in lower community UTI; carbapenems should be reserved for severe disease or patients with documented/high-probability ESBL or other highly resistant organisms, followed by prompt de-escalation when culture results permit.

Risk Factors for Resistant CA-UTI

Table 3. Major resistance risk factors identified across included studies

Community Residence Versus Long-Term-Care Exposure

Residential setting substantially modified resistance risk. Rosello et al. found that long-term-care residents aged ≥70 years had more than twice the laboratory-confirmed E. coli/Klebsiella UTI rate of community-dwelling older adults and more than four times the rate of UTI caused by organisms resistant to trimethoprim, nitrofurantoin, ciprofloxacin, or third-generation cephalosporins.

Labuschagne et al. analyzed 50,704 urine cultures from adults aged ≥60 years in South Africa. Long-term-care residence was independently associated with increased E. coli resistance to ciprofloxacin (adjusted OR 1.26), nitrofurantoin (1.55), ceftriaxone (1.24), amoxicillin-clavulanate (1.11), and co-trimoxazole (1.10).

Older adults living in the community and those residing in care facilities should therefore not automatically be treated as one epidemiological group.

Polymicrobial Infection

Polymicrobial infection occurred in 69 of 427 patients (16.16%) in the 2024 CA-UTI cohort. It was significantly associated with diabetes (p=0.007), prior antimicrobial use (p=0.025), and recurrent UTI (p=0.043). Polymicrobial disease further reduces the reliability of standard empirical regimens because treatment must adequately cover multiple organisms and may reflect underlying urinary tract abnormalities.

Inadequate Empirical Therapy

Resistance substantially increased the likelihood that initial antimicrobial therapy was microbiologically inactive. In the Madrazo cohort, inadequate empirical antimicrobial therapy occurred in 33.3% of MDR infections compared with 16.2% of non-MDR infections (p<0.001).

In Artero et al., inadequate empirical treatment occurred in 62.3% of ESBL-producing E. coli infections compared with 5.3% of non-ESBL infections. Delayed active therapy is a plausible mechanism linking AMR to prolonged symptoms, bacteremia, sepsis, and greater healthcare utilization.

Length of Stay and Mortality

In Madrazo et al., median hospital stay was longer in the MDR group (6 [IQR 4–8] days) than the non-MDR group (5 [IQR 4–7] days; p=0.029). In Artero et al., ESBL-producing E. coli infection was likewise associated with a longer average hospital stay.

The mortality signal was less consistent. Madrazo et al. observed hospital mortality of 8.6% without a significant MDR/non-MDR difference. Artero et al. reported mortality of 13% in the ESBL group and 7.5% in the non-ESBL group, but the difference was not statistically significant. These findings suggest that resistance has a clearer effect on treatment adequacy and resource utilization than on independently attributable mortality within older-adult CA-UTI cohorts.

Recurrence and Clinical Outcomes

In the prospective longitudinal study by Al Qahtani et al., UTI incidence over two years was 38.0% in adults aged ≥65 years compared with 12.8% in younger adults. Older patients had lower complete-recovery rates, more recurrent UTI (43.5% vs 22.2%), and more antibiotic-resistant infection (11.7% vs 2.78%). Advanced age, female sex, diabetes, immunosuppression, and renal stones were associated with recurrent disease.

Empirical Antibiotic Choice

Ahmed et al. evaluated 42,298 primary-care patients aged ≥65 years empirically treated with nitrofurantoin, cefalexin, ciprofloxacin, or co-amoxiclav. Compared with nitrofurantoin, alternative antibiotics were associated with fewer reconsultations and repeat prescriptions, but broader therapy did not improve major outcomes and some agents were associated with higher observed sepsis hospitalization or mortality. Because treatment choice was observational and likely affected by illness severity, these results require cautious interpretation and should not be viewed as direct comparative toxicity estimates.

Summary of Susceptibility Patterns

Table 4. General antimicrobial susceptibility pattern in older-adult CA-UTI evidence

4.18 Risk-of-Bias Assessment

Most included studies were judged to have low-to-moderate or moderate overall risk of bias. The most frequent concerns were selective culturing of patients with recurrent/complicated disease, inclusion of hospitalized community-onset cases, imperfect distinction between symptomatic UTI and asymptomatic bacteriuria in laboratory databases, variability in AMR definitions and susceptibility breakpoints, and residual confounding.

Table 5. Study-level risk-of-bias assessment

Overall summary: 1 study was rated low risk, 6 low-to-moderate risk, and 6 moderate risk; none was judged high risk across all major domains.

Principal Findings

This systematic review demonstrates that antimicrobial resistance is now an important feature of community-acquired and community-onset UTI among older adults.

Four observations were especially consistent. First, E. coli remains the dominant pathogen, but older adults show a broader uropathogen spectrum than younger women with uncomplicated cystitis. Second, resistance to traditional oral agents—including fluoroquinolones, trimethoprim-sulfamethoxazole, and aminopenicillins—is high enough in many settings to compromise purely empirical prescribing. Third, previous antibiotic exposure, recurrent UTI, healthcare exposure, and residential setting are major predictors of resistance. Fourth, MDR/ESBL infection increases the likelihood of inadequate initial therapy and prolonged hospitalization.

Why Older Adults Are Particularly Vulnerable

Advanced age is best understood as a marker of accumulated biological and healthcare exposures rather than a direct cause of resistance. Older adults more commonly experience repeated antimicrobial treatment, recurrent UTI, diabetes, chronic kidney disease, urinary retention, benign prostatic enlargement, urolithiasis, neurogenic bladder, hospitalization, urinary catheterization, and long-term-care residence.

These factors create repeated opportunities for selection, acquisition, and persistence of resistant organisms.

Antibiotic Exposure as a Modifiable Risk Factor

Previous antibiotic exposure was one of the most reproducible modifiable predictors of resistant infection. The particularly strong relationship between prior fluoroquinolone prescribing and ciprofloxacin-resistant E. coli supports careful review of recent prescription history before empirical treatment.

Antimicrobial exposure can exert selective pressure not only during treatment but also after the symptomatic episode, increasing the probability that subsequent colonization or infection will involve resistant organisms.

Diagnostic Stewardship and Asymptomatic Bacteriuria

One of the most important resistance-reduction strategies in geriatric medicine is avoiding antimicrobial therapy when a symptomatic UTI is not present.

Asymptomatic bacteriuria is common in older adults, particularly in long-term-care facilities. Nonspecific manifestations should not automatically be attributed to UTI. Unnecessary urine testing can lead to detection of colonizing organisms and inappropriate treatment, exposing patients to adverse effects while selecting resistant flora.

Diagnostic stewardship should therefore accompany prescribing stewardship.

Community Acquisition Does Not Mean Susceptibility

The historical assumption that community-acquired organisms are usually susceptible is increasingly unreliable. ESBL-producing and fluoroquinolone-resistant Enterobacterales are well established outside hospitals.

Accordingly, empirical treatment should incorporate recent healthcare exposure, previous resistant isolates, antimicrobial use, and residential setting even when symptoms begin in the community.

Geographical Heterogeneity

The contrast between Dutch and Argentine cohorts is particularly illustrative. Ciprofloxacin resistance in E. coli was approximately 10% in the Dutch elderly cohort but exceeded 50% in Argentina.

International guidance cannot replace local surveillance. Ideally, empirical treatment algorithms for older adults should be informed by community-specific, age-specific, and long-term-care-specific antibiograms together with the patient's own previous microbiology.

Clinical Consequences of Resistance

The most consistent clinical consequence of resistance was inadequate initial therapy. MDR infection approximately doubled the rate of inactive empirical treatment in the Madrazo cohort, while ESBL production increased it markedly in the Artero study.

Delayed active therapy provides a plausible pathway to prolonged symptoms, recurrent consultation, bacteremia, sepsis, and increased length of stay. The independent effect of resistance on mortality is more difficult to isolate because frailty, multimorbidity, renal impairment, functional dependency, and acute disease severity strongly influence outcomes.

Antimicrobial Stewardship Implications

Stewardship for older-adult UTI should combine diagnostic and therapeutic strategies: avoid unnecessary urine cultures, do not treat asymptomatic bacteriuria in the absence of a specific indication, obtain cultures before treatment in recurrent/complicated/severe UTI, review previous resistance history, minimize unnecessary fluoroquinolone exposure, select the narrowest effective agent, and de-escalate broad-spectrum treatment promptly when susceptibilities are available.

Clinical Implications

The evidence does not support a single universal empirical antibiotic for all older adults. Choice should depend on infection site, disease severity, renal function, prior cultures, recent antimicrobial exposure, local resistance, allergy history, and likelihood of complicated infection.

For selected lower-tract infection, nitrofurantoin or fosfomycin may retain useful activity in many settings when the likely pathogen and renal function are appropriate. Nitrofurantoin should not be used for pyelonephritis or systemic infection.

For systemic UTI, pyelonephritis, bacteremia, or sepsis, agents achieving adequate renal-tissue and systemic concentrations are required. Patients with previous ESBL infection, repeated recent antibiotics, long-term-care residence, recent hospitalization, or severe sepsis may require broader initial treatment, followed by culture-directed de-escalation.

Local age- and residence-specific antibiograms are especially important because resistance patterns in long-term-care residents can differ substantially from those in independently living older adults.

Strengths of the Review

• Specific focus on older adults rather than an all-age UTI population.
• Integration of microbiological, resistance-risk, and clinical-outcome evidence.
• Inclusion of community, primary-care, long-term-care, hospital-admission, and population-surveillance settings.
• Evaluation of both MDR and specific antimicrobial classes.
• Consideration of ESBL-producing Enterobacterales.
• Inclusion of contemporary evidence through September 2026.
• Formal study-level risk-of-bias assessment.
• Explicit consideration of geographical and residential-setting heterogeneity.

Limitations

Definitions of community-acquired and community-onset UTI differed between studies.

Age thresholds varied, although the principal synthesis prioritized populations aged ≥60 or ≥65 years.

Urine cultures are more likely to be obtained in patients with recurrent, complicated, or treatment-resistant infection, potentially overestimating resistance in all community UTI.

Some surveillance databases cannot reliably distinguish symptomatic UTI from asymptomatic bacteriuria.

Susceptibility-testing panels and interpretive breakpoints changed over time.

Geographical heterogeneity was substantial and limits pooled generalization.

Several studies included hospitalized patients with community-onset infection, which may enrich the population for frailty and complicated disease.

Frailty, functional deterioration, and quality-of-life outcomes remain poorly characterized.

A de novo meta-analysis was not appropriate because comparable older-adult-specific data were limited.

Future Research

• Use standardized definitions of symptomatic community-acquired UTI.
• Explicitly distinguish symptomatic UTI from asymptomatic bacteriuria.
• Report resistance by older-adult age strata.
• Separate community-dwelling and long-term-care populations.
• Standardize reporting of recent antimicrobial exposure.
• Use internationally accepted MDR and ESBL definitions.
• Report susceptibility to oral treatment options in a standardized manner.
• Report treatment failure, recurrence, bacteremia, and mortality at consistent time points.
• Adjust clinical-outcome analyses for frailty, functional status, renal function, and comorbidity.
• Develop and validate patient-level prediction tools for resistant infection.
• Generate more prospective evidence from low- and middle-income countries.
• Evaluate the impact of diagnostic and antimicrobial-stewardship interventions on subsequent resistance.

Antimicrobial resistance is an increasingly important problem in community-acquired urinary tract infections among older adults.

Escherichia coli remains the principal uropathogen, but Klebsiella pneumoniae, Proteus spp., Enterococcus spp., Pseudomonas aeruginosa, and polymicrobial infections become increasingly important with recurrent disease, comorbidity, structural urinary abnormalities, and healthcare exposure.

Resistance to fluoroquinolones, trimethoprim-sulfamethoxazole, aminopenicillins, and cephalosporins is substantial in many settings, while nitrofurantoin and fosfomycin generally retain better activity against susceptible lower-tract E. coli. Carbapenems remain highly active in many datasets but should be preserved for severe or highly resistant infection.

The most reproducible predictors of resistance are previous antibiotic exposure, recurrent UTI, prior hospitalization or healthcare contact, long-term-care exposure, advanced age, diabetes or other comorbidity, and urinary instrumentation or structural disease.

MDR and ESBL infection increase the likelihood of inadequate empirical therapy and are associated with longer hospitalization. Their independent effect on mortality in strictly community-acquired older-adult cohorts remains less certain.

Management should therefore move away from age alone toward individualized resistance-risk assessment, culture-guided treatment, local age- and setting-specific antibiograms, review of previous microbiological results, and rigorous antimicrobial stewardship. Avoidance of unnecessary treatment for asymptomatic bacteriuria is equally important to reduce harm and slow resistance selection.

1. Page MJ, McKenzie JE, Bossuyt PM, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ. 2021;372:n71.
2. Nicolle LE, Gupta K, Bradley SF, 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(10):e83-e110.
3. Magiorakos AP, Srinivasan A, Carey RB, et al. Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria: an international expert proposal for interim standard definitions for acquired resistance. Clin Microbiol Infect. 2012;18(3):268-281.
4. Swami SK, Liesinger JT, Shah N, Baddour LM, Banerjee R. Incidence of antibiotic-resistant Escherichia coli bacteriuria according to age and location of onset: a population-based study from Olmsted County, Minnesota. Mayo Clin Proc. 2012;87(8):753-759.
5. Fagan M, Lindbæk M, Grude N, et al. Antibiotic resistance patterns of bacteria causing urinary tract infections in the elderly living in nursing homes versus the elderly living at home: an observational study. BMC Geriatr. 2015;15:98.
6. Mulder M, Kiefte-de Jong JC, Goessens WHF, et al. Risk factors for resistance to ciprofloxacin in community-acquired urinary tract infections due to Escherichia coli in an elderly population. J Antimicrob Chemother. 2017;72(1):281-289.
7. Rosello A, Hayward AC, Hopkins S, et al. Impact of long-term care facility residence on the antibiotic resistance of urinary tract Escherichia coli and Klebsiella. J Antimicrob Chemother. 2017;72(4):1184-1192.
8. Leoni AF, Monterisi A, Acuña PG. Community acquired urinary tract infections in older adults. Rev Fac Cien Med Univ Nac Cordoba. 2017;74(1):10-17.
9. Artero A, Esparcia A, Alberola J, Madrazo M, Nogueira JM, Eiros JM. Prospective cohort study of risk factors for extended-spectrum beta-lactamase-producing Escherichia coli urinary tract infections in elderly patients admitted to hospital. Int J Clin Pract. 2017;71(9):e13001.
10. Ahmed H, Farewell D, Francis NA, Paranjothy S, Butler CC. Choice of empirical antibiotic therapy and adverse outcomes in older adults with suspected urinary tract infection: cohort study. Open Forum Infect Dis. 2019;6(3):ofz039.
11. Larramendy S, Deglaire V, Dusollier P, et al. Risk factors of extended-spectrum beta-lactamases-producing Escherichia coli community-acquired urinary tract infections: a systematic review. Infect Drug Resist. 2020;13:3945-3955.
12. Madrazo M, Esparcia A, López-Cruz I, et al. Clinical impact of multidrug-resistant bacteria in older hospitalized patients with community-acquired urinary tract infection. BMC Infect Dis. 2021;21:1232.
13. Taha AB. Bacterial etiology and antimicrobial resistance pattern of community-acquired urinary tract infection in older adults. Medicine in Microecology. 2024;22:100114.
14. Al Qahtani M, Naghib MEM, Alshamrani AMM, et al. The incidence, clinical features and outcome of urinary tract infections in geriatric patients: a prospective longitudinal study. IJID Reg. 2024;13:100469.
15. Alkan S, Balkan II, Surme S, et al. Urinary tract infections in older adults: associated factors for extended-spectrum beta-lactamase production. Front Microbiol. 2024;15:1384392.
16. Zhu NJ, Weldegiorgis M, Carter E, et al. Economic burden of community-acquired antibiotic-resistant urinary tract infections: systematic review and meta-analysis. JMIR Public Health Surveill. 2024;10:e53828.
17. Labuschagne O, Leigh S, Kingsburgh C, Williams CD. Antibacterial resistance in urinary samples from long-term care-facility and community-dwelling older people in Gauteng, South Africa. J Glob Antimicrob Resist. 2026;47:95-104.
18. Heltveit-Olsen SR, Grude N, Arnljots ES, et al. Microbiological findings, antibiotic resistance rates and prescription practices for older women with recurrent urinary tract infections: a descriptive study alongside a multinational randomized controlled trial (ImpresU). JAC Antimicrob Resist. 2026;8(4):dlag121.