Patient characteristics but not virulence factors discriminate between asymptomatic and symptomatic E. coli bacteriuria in the hospital

The Role of Mobile Genetic Elements in Virulence Factor Carriage from Symptomatic and Asymptomatic Cases of Escherichia coli Bacteriuria

Uropathogenic Escherichia coli (UPEC) is extremely diverse genotypically and phenotypically. Individual strains can variably carry diverse virulence factors, making it challenging to define a molecular signature for this pathotype. For many bacterial pathogens, mobile genetic elements (MGEs) constitute a major mechanism of virulence factor acquisition. For urinary E. coli, the total distribution of MGEs and their role in the acquisition of virulence factors is not well defined, including in the context of symptomatic infection versus asymptomatic bacteriuria (ASB). In this work, we characterized 151 isolates of E. coli, derived from patients with either urinary tract infection (UTI) or ASB. For both sets of E. coli, we catalogued the presence of plasmids, prophage, and transposons. We analyzed MGE sequences for the presence of virulence factors and antimicrobial resistance genes. These MGEs were associated with only ~4% of total virulence associated genes, while plasmids contributed to ~15% of antimicrobial resistance genes under consideration. Our analyses suggests that, across strains of E. coli, MGEs are not a prominent driver of urinary tract pathogenesis and symptomatic infection. IMPORTANCE Escherichia coli is the most common etiological agent of urinary tract infections (UTIs), with UTI-associated strains designated "uropathogenic" E. coli or UPEC. Across urinary strains of E. coli, the global landscape of MGEs and its relationship to virulence factor carriage and clinical symptomatology require greater clarity. Here, we demonstrate that many of the putative virulence factors of UPEC are not associated with acquisition due to MGEs. The current work enhances our understanding of the strain-to-strain variability and pathogenic potential of urine-associated E. coli and points toward more subtle genomic differences distinguishing ASB from UTI isolates.

E. coli catheter-associated urinary tract infections are associated with distinctive virulence and biofilm gene determinants

Urinary catheterization facilitates urinary tract colonization by E. coli and increases infection risk. Here, we aimed to identify strain-specific characteristics associated with the transition from colonization to infection in catheterized patients. In a single-site study population, we compared E. coli isolates from patients with catheter-associated asymptomatic bacteriuria (CAASB) to those with catheter-associated urinary tract infection (CAUTI). CAUTI isolates were dominated by a phylotype B2 subclade containing the multidrug-resistant ST131 lineage relative to CAASB isolates, which were phylogenetically more diverse. A distinctive combination of virulence-associated genes was present in the CAUTI-associated B2 subclade. Catheter-associated biofilm formation was widespread among isolates and did not distinguish CAUTI from CAASB strains. Preincubation with CAASB strains could inhibit catheter colonization by multiple ST131 CAUTI isolates. Comparative genomic analysis identified a group of variable genes associated with high catheter biofilm formation present in both CAUTI and CAASB strains. Among these, ferric citrate transport (Fec) system genes were experimentally associated with enhanced catheter biofilm formation using reporter and fecA deletion strains. These results are consistent with a variable role for catheter biofilm formation in promoting CAUTI by ST131-like strains or resisting CAUTI by lower-risk strains that engage in niche exclusion.

Using clinical decision support to improve urine culture diagnostic stewardship, antimicrobial stewardship, and financial cost: A multicenter experience

OBJECTIVE

Despite evidence to the contrary, many practitioners continue to inappropriately screen for and treat bacteria in the urine of clinically asymptomatic patients. The purpose of this study was to evaluate the impact of a new order set on the number of urine culture performed, antibiotic days of therapy (DOT), catheter-associated urinary tract infections (CAUTI), and associated financial impact.

DESIGN

A quasi-experimental before-and-after intervention.

SETTING

We conducted this study at 5 Catholic Health Initiative (CHI) hospitals in Texas that use the same electronic health record (EHR) system.

PATIENTS

The study populations included adult patients who had urine culture performed from June 2017 to June 2019.

INTERVENTION

The intervention (implemented June 25, 2018) was the addition of a new order set in the electronic health record that required practitioners to choose an indication for the type of urine study. The primary outcome was number of urine cultures performed adjusted for the number of total patient days.

RESULTS

Following implementation of the new order set, the number of urine cultures performed among the 5 sites decreased from 1,175.8 tests per 10,000 patient days before the intervention to 701.4 after the intervention (40.4% reduction; P < .01). Antibiotic DOT for patients with a urinary tract infection indication decreased from 102.5 to 86.9 per 1,000 patient days (15.2% reduction; P < .01). The CAUTI standardized infection ratio was 1.0 before the intervention and 0.8 after the intervention (P = .23). The estimated yearly savings following the intervention was US$535,181.

CONCLUSIONS

The addition of a new order set resulted in decreases in the number of urine cultures performed and the antibiotic DOT, as well as substantial financial savings.

Bacteriuria and vitamin D deficiency: a cross sectional study of 385 nursing home residents

Background

Up to half of elderly people at nursing homes have asymptomatic bacteriuria, and concentrations of 25-hydroxyvitamin D (25OHD) are generally low. Vitamin D is a modulator of the immune system and involved in protection of the epithelium in the urinary tract as well. The objective was to determine a possible association between bacteriuria and vitamin D deficiency among elderly people at nursing homes.

Methods

Cross-sectional study: Voided urine specimens and blood samples for cultivation and analysis of 25OHD were collected from elderly people at nursing homes in Sweden. Exclusion criteria were: urinary catheter, ongoing antibiotic treatment, incontinence or dementia too severe to provide a voided urine specimen or leave a blood sample, unwillingness to participate or terminal illness. Urine cultures and serum 25OHD concentrations were outcome measures and the association of bacteriuria with vitamin D deficiency was determined by logistic regression.

Results

Twenty-two nursing homes participated and 385 of 901elderly people provided voided urine specimens and blood samples. The mean age was 87 (SD 6.7), 69% women, 19% received vitamin D supplement, 13% had diabetes mellitus, and 54% were diagnosed with dementia. There was significant growth of potentially pathogenic bacteria in 32% (123/385) of voided urine specimens. Escherichia coli were present in 83% of positive urine cultures. The mean concentration of 25OHD in serum was 35 nmol/L (SD 21). Thirty-seven per cent (143/385) had 25OHD < 25 nmol/L, and 3.1% (12/385) 25OHD < 12.5 nmol/L. No association between bacteriuria and 25OHD < 25 nmol/L, OR 1.4 (0.86–2.3; p = 0.18) adjusted for age, gender, diabetes mellitus and dementia was found. However, if using 25OHD < 12.5 nmol/L as a cut-off for vitamin D deficiency the adjusted odds-ratio was 4.4 (1.1–17; p = 0.031).

Conclusions

Bacteriuria and vitamin D deficiency was common. No association between bacteriuria and 25OHD < 25 nmol/L was found. If using 25OHD < 12.5 nmol/L as cut-off for vitamin D deficiency there was an association. However, this has to be interpreted with caution as causality cannot be evaluated as well as only few residents had 25OHD < 12.5 nmol/L.

The burden of comorbidity is associated with symptomatic polymicrobial urinary tract infection among institutionalized elderly

BACKGROUND

Urinary tract infections (UTIs), often sustained by polymicrobial flora (p-UTIs), are a common finding among nursing home patients, and associated with adverse outcomes and increased healthcare costs. P-UTIs have been extensively studied with regard to microbiological aspects. However, little is known about the characteristics of the host.

AIMS

The aim of this study is to verify to which extent comorbidity characterizes elderly nursing home patients with p-UTIs.

METHODS

We enrolled 299 patients with culture-positive UTI consecutively admitted to the nursing home of the "Fondazione San Raffaele Cittadella della Carità", Taranto, Italy. P-UTI was diagnosed when two uropathogens were simultaneously isolated. The burden of comorbidity was quantified using the Charlson comorbidity score index. Logistic regression analysis was used to assess the adjusted association of the variables of interest with the presence of p-UTI.

RESULTS

P-UTIs were detected in 118/299 (39%) patients. According to logistic regression, the presence of p-UTIs was independently associated with the Charlson index (OR 1.70; 95% CI 1.06-2.72; P = .026). This association remained also after excluding participants without urinary catheter (OR 1.88; 95% CI 1.13-3.11; P = .015).

DISCUSSION

The presence of P-UTIs is associated with the burden of comorbidity, but not with individual diseases.

CONCLUSIONS

Older nursing home patients with comorbidity should be screened for the presence of p-UTIs; further studies are needed to evaluate the impact of early detection and treatment of p-UTIs on the development of comorbidity.

Beyond Urinary Tract Infections (UTIs) and Delirium: A Systematic Review of UTIs and Neuropsychiatric Disorders

Urinary tract infections (UTIs) are among the most common bacterial infections. Although comorbid UTI in geriatric patients with delirium or dementia is well known, the prevalence and scope of the association with other neuropsychiatric disorders is unclear. We performed a systematic review of the association between UTIs and delirium, dementia, psychotic disorders, and mood disorders in hospitalized patients. We identified studies by searching PubMed, PsycInfo, and Web of Knowledge, and the reference lists of identified studies and review papers. Seventeen publications met the inclusion criteria. The primary findings were: (1) 88% of publications reported a positive association between UTIs and neuropsychiatric disorders; (2) 47% reported that the clinical course of a neuropsychiatric disorder may be precipitated or exacerbated by a UTI; (3) the mean weighted prevalence of UTIs in subjects was 19.4% for delirium, 11.2% for dementia, 21.7% for nonaffective psychotic disorders, and 17.8% for mood disorders. Our findings, which must be interpreted carefully given the heterogeneity among the studies, suggest that UTIs are highly comorbid in hospitalized patients and may precipitate or exacerbate some neuropsychiatric disorders. The association extends beyond geriatric patients with delirium, affects males and females, and includes adults with psychotic and mood disorders. These findings underscore the important interface between physical and mental health. Potential underlying mechanisms are also reviewed, including complex interactions between the immune system and the brain.

Bacteruria and Urinary Tract Infections in the Elderly

Both urinary tract infection (UTI) and asymptomatic bacteriuria (ASB) are common problems among elderly adults and represent a significant health care burden. Despite their frequency, differentiating between ASB and true UTI remains controversial among health care providers. Several challenges exist in the evaluation of urinary symptoms in the elderly patient. Symptoms of UTI are variable; problems are encountered in the collection, testing, and interpretation of urine specimens; and results of urinalysis are often misinterpreted and mishandled. Multiple studies have shown no morbidity or mortality benefit to antibiotic therapy in either community or long-term care facility residents with ASB.

Urinary tract infections in the critical care unit: A brief review

The use of indwelling catheters in the Critical Care Units (CCUs) has a major role in determining the incidence and the morbidity as well as mortality from hospital-acquired urinary tract infections (UTIs). Instituting evidence-based protocols can significantly reduce both the prevalence of indwelling catheterization as well as the incidence of hospital-acquired UTIs. The prevalence of catheter-associated urinary tract infections (CAUTIs) in the CCUs is directly linked to the widespread use of indwelling catheters in these settings. CAUTIs result in significant cost escalation for individual hospitals as well as the healthcare system as a whole. A UTI is an inflammatory response to colonization of the urinary tract, most commonly by bacteria or fungi. A UTI should be differentiated from the mere detection of bacteria in the urinary tract. This condition, referred to as asymptomatic bacteriuria, is common and does not require treatment, especially in the patient with an indwelling urinary catheter. A CAUTI occurs when a patient with an indwelling urinary catheter develops 2 or more signs or symptoms of a UTI such as hematuria, fever, suprapubic or flank pain, change in urine character, and altered mental status. CAUTI is classified as a complicated UTI. The current review highlights the important management issues in critical care patients having CAUTI. We performed a MEDLINE search using combinations of keywords such as urinary tract infection, critical care unit and indwelling urinary catheter. We reviewed the relevant publications with regard to CAUTI in patients in CCU.