Asymptomatic bacteriuria in the elderly: high prevalence and high turnover of strains

A reference standard for urinary tract infection research: a multidisciplinary Delphi consensus study

The absence of a consensus-based reference standard for urinary tract infection (UTI) research adversely affects the internal and external validity of diagnostic and therapeutic studies. This omission hinders the accumulation of evidence for a disease that imposes a substantial burden on patients and society, particularly in an era of increasing antimicrobial resistance. We did a three-round Delphi study involving an international, multidisciplinary panel of UTI experts (n=46) and achieved a high degree of consensus (94%) on the final reference standard. New-onset dysuria, urinary frequency, and urinary urgency were considered major symptoms, and non-specific symptoms in older patients were not deemed indicative of UTI. The reference standard distinguishes between UTI with and without systemic involvement, abandoning the term complicated UTI. Moreover, different levels of pyuria were incorporated in the reference standard, encouraging quantification of pyuria in studies done in all health-care settings. The traditional bacteriuria threshold (105 colony-forming units per mL) was lowered to 104 colony-forming units per mL. This new reference standard can be used for UTI research across many patient populations and has the potential to increase homogeneity between studies.

Diagnostic accuracy of urine biomarkers for urinary tract infection in older women: a case-control study

OBJECTIVES

Urinary tract infection (UTI) is common among older women. However, diagnosis is challenging because of frequent chronic lower urinary tract symptoms, cognitive impairment, and a high prevalence of asymptomatic bacteriuria (ASB). Current urine diagnostics lack specificity, leading to unnecessary treatment and antimicrobial resistance. This study aimed to evaluate the diagnostic accuracy of 12 urine biomarkers for diagnosing UTI in older women.

METHODS

In this case-control study, cases were women ≥65 years with ≥2 new-onset lower urinary tract symptoms, pyuria, and one uropathogen ≥104 CFU/mL. Controls were asymptomatic and classified as ASB (one uropathogen ≥105 CFU/mL), negative culture, or mixed flora. Urine biomarker concentrations were measured through liquid chromatography-mass spectrometry and ELISA. Diagnostic accuracy parameters of individual biomarkers and a biomarker model were derived from receiver operating characteristic curves.

RESULTS

We included 162 community-dwelling and institutionalized older women. Five urine inflammatory biomarkers demonstrated high discriminative ability (area under the curve ≥0.80): interleukin 6, azurocidin, neutrophil gelatinase-associated lipocalin, tissue inhibitor of metalloproteinases 2, and C-X-C motif chemokine 9. Azurocidin exhibited the highest diagnostic accuracy (sensitivity 86% [95% CI 75%-93%] and specificity 89% [95% CI 82%-94%] at 16.7 ng/mmol creatinine). A combined biomarker and pyuria model showed improved diagnostic accuracy in patients with UTI and ASB, compared with pyuria alone.

DISCUSSION

We identified several urine biomarkers that accurately differentiated older women with UTI from asymptomatic women, including ASB. These findings represent a potential advancement towards improved diagnostics for UTI in older women and warrant validation in a diverse population.

Definitions of Urinary Tract Infection in Current Research: A Systematic Review

Defining urinary tract infection (UTI) is complex, as numerous clinical and diagnostic parameters are involved. In this systematic review, we aimed to gain insight into how UTI is defined across current studies. We included 47 studies, published between January 2019 and May 2022, investigating therapeutic or prophylactic interventions in adult patients with UTI. Signs and symptoms, pyuria, and a positive urine culture were required in 85%, 28%, and 55% of study definitions, respectively. Five studies (11%) required all 3 categories for the diagnosis of UTI. Thresholds for significant bacteriuria varied from 103 to 105 colony-forming units/mL. None of the 12 studies including acute cystitis and 2 of 12 (17%) defining acute pyelonephritis used identical definitions. Complicated UTI was defined by both host factors and systemic involvement in 9 of 14 (64%) studies. In conclusion, UTI definitions are heterogeneous across recent studies, highlighting the need for a consensus-based, research reference standard for UTI.

Current Pyuria Cutoffs Promote Inappropriate Urinary Tract Infection Diagnosis in Older Women

BACKGROUND

Pre-existing lower urinary tract symptoms (LUTS), cognitive impairment, and the high prevalence of asymptomatic bacteriuria (ASB) complicate the diagnosis of urinary tract infection (UTI) in older women. The presence of pyuria remains the cornerstone of UTI diagnosis. However, >90% of ASB patients have pyuria, prompting unnecessary treatment. We quantified pyuria by automated microscopy and flowcytometry to determine the diagnostic accuracy for UTI and to derive pyuria thresholds for UTI in older women.

METHODS

Women ≥65 years with ≥2 new-onset LUTS and 1 uropathogen ≥104 colony-forming units (CFU)/mL were included in the UTI group. Controls were asymptomatic and classified as ASB (1 uropathogen ≥105 CFU/mL), negative culture, or mixed flora. Patients with an indwelling catheter or antimicrobial pretreatment were excluded. Leukocyte medians were compared and sensitivity-specificity pairs were derived from a receiver operating characteristic curve.

RESULTS

We included 164 participants. UTI patients had higher median urinary leukocytes compared with control patients (microscopy: 900 vs 26 leukocytes/µL; flowcytometry: 1575 vs 23 leukocytes/µL; P < .001). Area under the curve was 0.93 for both methods. At a cutoff of 264 leukocytes/µL, sensitivity and specificity of microscopy were 88% (positive and negative likelihood ratio: 7.2 and 0.1, respectively). The commonly used cutoff of 10 leukocytes/µL had a poor specificity (36%) and a sensitivity of 100%.

CONCLUSIONS

The degree of pyuria can help to distinguish UTI in older women from ASB and asymptomatic controls with pyuria. Current pyuria cutoffs are too low and promote inappropriate UTI diagnosis in older women. Clinical Trials Registration. International Clinical Trials Registry Platform: NL9477 (https://trialsearch.who.int/Trial2.aspx?TrialID=NL9477).

The Diagnostic Accuracy Of Procalcitonin for Urinary Tract Infection in Hospitalized Older Adults: a Prospective Study

BACKGROUND

The diagnosis of urinary tract infection (UTI) is challenging among hospitalized older adults, particularly among those with altered mental status.

OBJECTIVE

To determine the diagnostic accuracy of procalcitonin (PCT) for UTI in hospitalized older adults.

DESIGN

We performed a prospective cohort study of older adults (≥65 years old) admitted to a single hospital with evidence of pyuria on urinalysis. PCT was tested on initial blood samples. The reference standard was a clinical definition that included the presence of a positive urine culture and any symptom or sign of infection referable to the genitourinary tract. We also surveyed the treating physicians for their clinical judgment and performed expert adjudication of cases for the determination of UTI.

PARTICIPANTS

Two hundred twenty-nine study participants at a major academic medical center.

MAIN MEASURES

We calculated the area under the receiver operating characteristic curve (AUC) of PCT for the diagnosis of UTI.

KEY RESULTS

In this study cohort, 61 (27%) participants met clinical criteria for UTI. The median age of the overall cohort was 82.6 (IQR 74.9-89.7) years. The AUC of PCT for the diagnosis of UTI was 0.56 (95% CI, 0.46-0.65). A series of sensitivity analyses on UTI definition, which included using a decreased threshold for bacteriuria, the treating physicians' clinical judgment, and independent infectious disease specialist adjudication, confirmed the negative result.

CONCLUSIONS

Our findings demonstrate that PCT has limited value in the diagnosis of UTI among hospitalized older adults. Clinicians should be cautious using PCT for the diagnosis of UTI in hospitalized older adults.

Infections in Older Adults

Infections in elderly patients can prove diagnostically challenging. Age-related factors affecting the immune system in older individuals contribute to nonspecific presentations. Other age-related factors and chronic conditions have symptoms that may or may not point to an infectious diagnosis. Delay in administration of antimicrobials can lead to poor outcomes; however, unnecessary administration of antimicrobials can lead to increased morbidity and contribute to the emergence of multidrug-resistant organisms. Careful clinical assessment and consideration of patient history and risk factors is crucial. When necessary, antimicrobials should be chosen that are appropriate for the diagnosis and deescalated as soon as possible.

Narrative Review: The Process of Expanding the Manual of Antimicrobial Stewardship by the Government of Japan

The Ministry of Health, Labour and Welfare has published the Manual of Antimicrobial Stewardship (1st edition) in June 2017 to improve the prescribing practice of antimicrobials for immunocompetent adult and pediatric (both school-aged and older children) patients. Due to the increasing demand for further promoting outpatient antimicrobial stewardship, we conducted a literature and national guideline review to identify the area of need. The results of our review revealed a high antimicrobial prescription rate in the Japanese pediatric population. Furthermore, although the Japanese clinical guidelines/guidance covered the fields of almost all infectious diseases, no system exists to estimate the incidence and treatment patterns of important infectious diseases such as asymptomatic bacteriuria, skin and soft tissue infections, and dental practices in Japan. Therefore, addressing the issues of both establishing surveillance systems and the implementation of guidelines/guidance can be the next step to promote further outpatient antimicrobial stewardship.

Antibiotic prescribing and non-prescribing in nursing home residents with signs and symptoms ascribed to urinary tract infection (ANNA): study protocol for a cluster randomized controlled trial

BACKGROUND

Antibiotic overprescribing for suspected urinary tract infection (UTI) in nursing homes (NHs) is common. Typical clinical scenarios in which antibiotics are inappropriately prescribed include response to nonspecific signs and symptoms and/or a positive urine test in the absence of symptoms referable to the urinary tract. These and other scenarios for inappropriate antibiotic prescribing were addressed in a recent international Delphi study which resulted in the development of a decision tool for the empiric treatment of UTI in frail older adults. The aim of the current study is to implement this decision tool, by integrating it into the electronic health record (EHR) and providing education on its content and use, and to evaluate its effect on appropriate antibiotic prescribing. An additional aim is to evaluate the quality of the intervention and the implementation process.

METHODS

A cluster Randomized Controlled Trial (cRCT) is conducted in sixteen NHs and aims to include 897 residents diagnosed with suspected UTI. NHs in the intervention group use the EHR-integrated decision tool, and receive education for physicians and nursing staff; in the control group care as usual is provided. Data is collected through case report forms within the EHR at the day of diagnosis and at 3, 7, and 21 days thereafter. The primary outcome is appropriate antibiotic prescribing for suspected UTI at the day of diagnosis. Secondary outcomes include the course of symptoms, alternative diagnoses, treatment changes, complications, hospitalization, and mortality. Data on total antibiotic prescribing are additionally collected in the participating NHs 12 months before and during the study. Finally, the process evaluation combines cRCT data with questionnaires and qualitative interviews with NH professionals.

DISCUSSION

This is the first cRCT to evaluate the recently developed, international decision tool for empiric treatment of suspected UTI in NH residents. Study findings will elucidate the effect of the intervention on appropriate antibiotic prescribing for suspected UTI, and provide insight into the applicability of the decision tool in NHs in general and in specific subgroups of NH residents. With this study we aim to contribute to antibiotic stewardship efforts in long-term care.

TRIAL REGISTRATION

The ANNA study was registered at the Netherlands Trial Register on 26 February 2019, with identification number NTR NL7555 .

Clinical Practice Guideline for the Management of Asymptomatic Bacteriuria: 2019 Update by the Infectious Diseases Society of America

Asymptomatic bacteriuria (ASB) is a common finding in many populations, including healthy women and persons with underlying urologic abnormalities. The 2005 guideline from the Infectious Diseases Society of America recommended that ASB should be screened for and treated only in pregnant women or in an individual prior to undergoing invasive urologic procedures. Treatment was not recommended for healthy women; older women or men; or persons with diabetes, indwelling catheters, or spinal cord injury. The guideline did not address children and some adult populations, including patients with neutropenia, solid organ transplants, and nonurologic surgery. In the years since the publication of the guideline, further information relevant to ASB has become available. In addition, antimicrobial treatment of ASB has been recognized as an important contributor to inappropriate antimicrobial use, which promotes emergence of antimicrobial resistance. The current guideline updates the recommendations of the 2005 guideline, includes new recommendations for populations not previously addressed, and, where relevant, addresses the interpretation of nonlocalizing clinical symptoms in populations with a high prevalence of ASB.

Treatment of urinary tract infections in the old and fragile

INTRODUCTION

Urinary tract infection (UTI) is highly prevalent in the frail elderly population. This review aimed to outline the diagnostic, treatment, and prevention of UTI in the frail aging population.

METHODS

Pubmed and Web of Science search to identify publications until March 2019 relating to the management of UTI in the elderly population was performed. A narrative review of the available literature was performed.

RESULTS

64 publications were considered as relevant and included in this review. The diagnosis of symptomatic UTI in the old and fragile could be challenging. Routine screening and antimicrobial therapy for asymptomatic bacteriuria should not be recommended for frail elderly patients. Cautious choice of antibiotics should be guided by uropathogen identified by culture and sensitivity. Understanding local antibiotic resistance rates plays a fundamental part in selecting appropriate antimicrobial treatment. Impact of associated adverse effect, in particular those with effects on cognitive function, should be considered when deciding choice of antibiotics for symptomatic UTI in the elderlies. Optimal management of comorbidities such as diabetes mellitus, adequate treatment of urinary incontinence, and judicious use of urinary catheter is essential to reduce the development of UTI.

CONCLUSION

UTI is a significant but common problem in elderly population. Physicians who care for frail elderly patients must be aware of the challenges in the management of asymptomatic UTI, and identifying symptomatic UTI in this population, and their appropriate management strategies. There is strong need in studies to evaluate nonantimicrobial therapies in the prevention of UTI for the frail elderly population.

Diagnosis of urinary tract infection in older persons in the emergency department: To pee or not to pee, that is the question

Doreen is a 79-year-old woman referred by her general practitioner to the ED for intravenous antibiotics for a urinary tract infection (UTI). She lives in a residential aged care facility (RACF) and staff report malodourous and cloudy urine. She denies dysuria or frequency. On examination Doreen is frail with vital signs of: temperature 37.7°C, pulse 87 bpm, blood pressure 130/70; there is no suprapubic or flank tenderness. Do you perform a dipstick test on Doreen’s urine for a suspected UTI?

Asymptomatic bacteriuria in older adults: the most fragile women are prone to long-term colonization

Background

The diagnosis of urinary tract infections (UTIs) in institutionalized older adults is often based on vague symptoms and a positive culture. The high prevalence of asymptomatic bacteriuria (ABU), which cannot be easily discriminated from an acute infection in this population, is frequently neglected, leading to a vast over-prescription of antibiotics. This study aimed to identify subpopulations predisposed to transient or long-term ABU.

Methods

Residents in a long-term care facility were screened for ABU. Mid-stream urine samples were collected during two sampling rounds, separated by 10 weeks, each consisting of an initial and a confirmative follow-up sample.

Results

ABU occurred in approximately 40% of the participants and was mostly caused by Escherichia coli. Long-term ABU (> 3 months) was found in 30% of the subjects. The frailest women with urinary incontinence and dementia had drastically increased rates of ABU and especially long-term ABU. ABU was best predicted by a scale describing the functional independence of older adults.

Conclusions

Institutionalized women with incontinence have ABU prevalence rates of about 80% and are often persistent carriers. Such prevalence rates should be considered in clinical decision making as they devalue the meaning of a positive urine culture as a criterion to diagnose UTIs. Diagnostic strategies are urgently needed to avoid antibiotic overuse and to identify patients at risk to develop upper UTI.

Electronic supplementary material

The online version of this article (10.1186/s12877-019-1181-4) contains supplementary material, which is available to authorized users.

Urine cultures in a long-term care facility (LTCF): time for improvement

Background

Urinary tract infections (UTIs) are the most prevalent infections in long-term care facilities (LTCFs). Numerous studies have described the problem of inadequate UTI diagnosis and treatment. We assessed the role of urine cultures in the diagnosis and treatment of UTIs in a LTCF.

Methods

In a 370-bed non-academic LTCF a retrospective assessment of antibiotic (AB) prescriptions for UTIs and urine cultures was performed from July 2014 to January 2016. The reasons why physicians, including 11 nursing home physicians and 2 junior doctors, ordered urine cultures were recorded using questionnaires.

Results

During the study period, 378 residents were prescribed 1672 AB courses; 803 were for UTIs. One hundred and fifty-five urine cultures were obtained from 135 residents; 66 of these cultures were performed on the same day as ABs were prescribed (8% of all prescriptions for UTI), while 89 were not. There was a discrepancy between the actions that seemed logical based on the culture results and the actions that were actually taken in 75% of the cases. In these cases, initial AB treatment was not adjusted when the isolated microorganism was resistant to the AB prescribed, the urine culture was positive and no ABs had previously been administered, or ABs were prescribed and no microorganism was isolated.

The most frequent reason for ordering a urine culture was to confirm the diagnosis of a UTI.

Conclusion

In the majority of patients, AB therapy was not adjusted when the urine culture results suggested it may be appropriate. The physicians were erroneously convinced that UTIs could be diagnosed by a positive urine culture.

Electronic supplementary material

The online version of this article (10.1186/s12877-018-0909-x) contains supplementary material, which is available to authorized users.

A descriptive study of adrenal crises in adults with adrenal insufficiency: increased risk with age and in those with bacterial infections

BACKGROUND

An adrenal crisis (AC) is a major cause of morbidity in hypoadrenal patients. However, there is little information available on the incidence and underlying causes of AC.

METHODS

The aim of the present study was to describe the incidence of AC in New South Wales (NSW), Australia. Using a health department database, we selected de-identified data on all adults aged 20 years and over who were treated in any hospital in NSW between July1, 2000-June 30, 2011, with either a principal or secondary diagnosis of an AC. AC admission rates were calculated overall and within age categories. Frequencies of co-morbid diagnoses were analysed by age and sex groups. Poisson regression was used to assess the significance of the observed change in AC related admissions with age, while controlling for any secular trends by including year in the model. Chi sq tests were used to assess the differences in frequencies of categorical variables between groups.

RESULTS

824 patients received treatment for an AC in hospital, corresponding to 74.9 admissions/year. The majority (62.5%) of the patients were women and 52.8% were aged 60 years and over. Admission rates were significantly associated with increasing age (p < 0.0001). Patients in the 60-69, 70-79 and 80+ age groups had the highest average admission rates (24.3, 35.2 and 45.8 per million/year). A principal or secondary diagnosis of an infection was reported in 317 (38.5%) patients and infection was significantly associated with age (p < 0.0001) with older patients having the highest proportion of cases. The most frequent infections were pneumonia/lower respiratory tract infection in 85 (10.3%) cases and urinary tract infection (UTI) in 82 (10.0%) patients. Women experienced 78.0% of the reported UTIs. There were 125 patients (15.2%) with an AC and a record of gastroenteritis. Twenty-six (3.2%) patients died in hospital but, of these, only 4 deaths (0.9%) were recorded among the 467 patients with a principal diagnosis of an AC.

CONCLUSIONS

The incidence of AC increases with age. Infections, especially bacterial infections, are associated with the incidence of ACs and this increases with age.

Approach to a positive urine culture in a patient without urinary symptoms

Asymptomatic bacteriuria (ASB) is a condition in which bacteria are present in a noncontaminated urine sample collected from a patient without signs or symptoms related to the urinary tract. ASB must be distinguished from symptomatic urinary tract infection (UTI) by the absence of signs and symptoms compatible with UTI or by clinical determination that a nonurinary cause accounts for the patient's symptoms. The overall purpose of this review is to promote an awareness of ASB as a distinct condition from UTI and to empower clinicians to withhold antibiotics in situations in which antimicrobial treatment of bacteriuria is not indicated.

Diagnosis and management of urinary tract infection in older adults

Urinary tract infection (UTI) is a commonly diagnosed infection in older adults. Despite consensus guidelines developed to assist providers in diagnosing UTI, distinguishing symptomatic UTI from asymptomatic bacteriuria (ASB) in older adults is problematic, as many older adults do not present with localized genitourinary symptoms. This article summarizes the recent literature and guidelines on the diagnosis and management of UTI and ASB in older adults.

Urinary tract infection in older adults

Urinary tract infection and asymptomatic bacteriuria are common in older adults. Unlike in younger adults, distinguishing symptomatic urinary tract infection from asymptomatic bacteriuria is problematic, as older adults, particularly those living in long-term care facilities, are less likely to present with localized genitourinary symptoms. Consensus guidelines have been published to assist clinicians with diagnosis and treatment of urinary tract infection; however, a single evidence-based approach to diagnosis of urinary tract infection does not exist. In the absence of a gold standard definition of urinary tract infection that clinicians agree upon, overtreatment with antibiotics for suspected urinary tract infection remains a significant problem, and leads to a variety of negative consequences including the development of multidrug-resistant organisms. Future studies improving the diagnostic accuracy of urinary tract infections are needed. This review will cover the prevalence, diagnosis and diagnostic challenges, management, and prevention of urinary tract infection and asymptomatic bacteriuria in older adults.

Acute abdominal pain in the older adult

Abdominal pain in older adults is a concerning symptom common to a variety of diagnoses with high morbidity and mortality. Organizing the differential into categories based on pathology (inflammatory, obstructive, vascular, or other causes) provides a framework for the history, physical, and diagnostic studies. An organized approach and treatment and considerations specific to the geriatric population are discussed.