Antimicrobial Resistance Trends in Urine Escherichia coli Isolates From Adult and Adolescent Females in the United States From 2011-2019: Rising ESBL Strains and Impact on Patient Management

Co-resistance Among Escherichia coli and Klebsiella pneumoniae Urine Isolates from Female Outpatients with Presumed UTI: A Retrospective US Cohort Study

INTRODUCTION

Urinary tract infections (UTIs) caused by antimicrobial-resistant Enterobacterales are a global health threat. There are limited surveillance data available to characterize the prevalence of antimicrobial resistance among outpatients in the United States (US).

METHODS

This retrospective cohort (database) study investigated co-resistance among Escherichia coli and Klebsiella pneumoniae urinary isolates from US female outpatients aged ≥ 12 years with presumed uncomplicated UTI (uUTI), ≥ 3 months of data (2011-2019), and antimicrobial susceptibility testing results. Eligible isolates were the first urinary E. coli or K. pneumoniae isolate per patient collected within 30 days; classified as not susceptible (NS) if antimicrobial susceptibility testing results were intermediate or resistant to each antibiotic tested. Four resistance phenotypes were identified: NS to fluoroquinolones (FQ), trimethoprim/sulfamethoxazole (SXT), nitrofurantoin (NTF), and extended-spectrum β-lactamase+/third-generation cephalosporin (ESBL+/3GC NS). Co-resistance phenotypes included all possible combinations of resistance to ≥ 2 drug classes.

RESULTS

Of 1,513,882 E. coli isolates and 250,719 K. pneumoniae isolates, 856,918 and 187,459 isolates with ≥ 1 resistance phenotype were included in the analysis, respectively. The most common resistance phenotypes were SXT NS for the E. coli isolates (44.8%) and NTF NS for the K. pneumoniae isolates (75.5%), while ESBL+/3GC NS comprised 11.2 and 5.9%, respectively. Among ESBL+/3GC NS E. coli isolates, 72.4, 56.7, and 46.6% were co-resistant to FQ, SXT, and FQ + SXT, respectively. For ESBL+/3GC NS K. pneumoniae isolates, 65.7 and 45.7% were co-resistant to SXT and FQ + SXT.

CONCLUSION

Both species exhibited high rates of co-resistance, emphasizing the need to raise awareness of co-resistance and of the unmet need for effective treatment options for uUTI.

Unitary Tract Infection Treatment: When to Use What Agents including Beta-lactam Combination Agents

In this study, the authors review antibiotic treatment options for both acute uncomplicated and complicated urinary tract infection (UTI). In addition, they also review regimens used in the setting of drug-resistant pathogens including vancomycin resistant Enterococcus, extended spectrum beta-lactamase (ESBL) producing Enterobacterals, carbapenem-resistant Enterobacterals and carbapenem-resistant Pseudomonas, which are encountered with increasing frequency.

Electronic Phenotyping of Urinary Tract Infections as a Silver Standard Label for Machine Learning

This study explored the efficacy of electronic phenotyping in data labeling for machine learning with a focus on urinary tract infections (UTIs). We contrasted labels from electronic phenotyping against previously published labels such as urine culture positivity. In comparison, electronic phenotyping showed the potential to enhance specificity in UTI labeling while maintaining similar sensitivity and was easily scaled for application to a large dataset suitable for machine learning, which we used to train and validate a machine learning model. Electronic phenotyping offers a valuable method for machine learning label generation in healthcare, with potential benefits for patient care and antimicrobial stewardship. Further research will expand its application and optimize techniques for increased performance.

Impact of an antimicrobial stewardship program indicator on the appropriateness of the empiric antibiotic treatment of urinary source Escherichia coli bacteraemia

A prospective multicentre study was carried out between 2017 and 2021 to assess (1) the appropriateness of the empirical treatment to the local guidelines of urinary source Escherichia coli bacteraemia, (2) the appropriateness of empirical treatment to antibiotic sensitivity results and (3) the degree of error in the local guidelines regarding the antibiotic sensitivity reported in acute care hospitals enrolled in the vigilància de les infeccions relacionades amb l'atenció sanitària de Catalunya program. During the study period, 79.0% of the empirical treatments analysed complied with the guidelines and 88.1% were appropriate in view of the in vitro activity of the isolated strain. The rate of appropriateness rose from 73.8% in 2017 to 81.0% in 2021 (P < 0.001). The degree of error in the recommendations regarding the in vitro activity of the isolated strains was 5.9% and remained stable during the study period. Antibiotic families correctly prescribed according to the guidelines were third-generation cephalosporins (54.9%), carbapenems (16.8%) and combinations of penicillins and beta-lactamase inhibitors (16.4%). Of the 8009 E. coli strains, 19.0% were extended-spectrum beta-lactamases producers, 36.8% were resistant to quinolones and 0.5% were resistant to carbapenems. The broad implementation of an antimicrobial stewardship program with quality indicators of antibiotic use improved compliance to local guidelines in the empiric treatment of urinary tract E. coli bacteraemia. The degree of error in local guidelines was low but higher in more complex hospitals and in healthcare-associated infections. Guidelines need to be constantly updated with the use of epidemiological data, rapid diagnostic tests and the analysis of patient risk factors specific to each geographical area.

Therapeutic strategies for uncomplicated cystitis in women

Uncomplicated cystitis is affecting many women of all ages and has a great impact on the quality of life, especially in women suffering from recurrent, uncomplicated cystitis. By far the most frequent uropathogen, E. coli, may have acquired increasing resistance against a variety of oral antibiotics, which may differ between countries and regions. Therefore, local resistance data are important to be considered. On the other hand, non-antibiotic therapy has also become an option which should be discussed and offered to the patient. In patients suffering from recurrent uncomplicated cystitis, individual risk factors and possible behavioral changes should first be taken into account. Non-antimicrobial prophylactic strategies shown to be successful in well-designed clinical studies are the next options. Long term antibiotic prophylaxis, however, should only be considered as a last option. For some of those patients self-diagnosis and self-treatment may be suitable, e.g. by using a recognized questionnaire.

Spatiotemporal distribution of community-acquired phenotypic extended-spectrum beta-lactamase Escherichia coli in United States counties, 2010-2019

Using data from the Veterans' Health Administration from 2010 to 2019, we examined the distribution and prevalence of community-acquired phenotypic extended-spectrum β-lactamase (ESBL) E. coli in the United States. ESBL prevalence slowly increased during the study period, and cluster analysis showed clustering in both urban and rural locations.

Evaluation of Oral Amoxicillin/Clavulanate for Urinary Tract Infections Caused by Ceftriaxone Non-Susceptible Enterobacterales

Urinary tract infections (UTIs) are one of the most common infections and are frequently caused by Gram-negative organisms. The rise of resistant isolates has prompted evaluation of alternative therapies, including amoxicillin-clavulanate which has potent activity against Ambler class A enzymes. This study sought to evaluate clinical outcomes of patients with ceftriaxone non-susceptible UTIs receiving amoxicillin-clavulanate or standard of care (SOC). This was a single-center, retrospective, cohort study of adult patients with urinary tract infections caused by a ceftriaxone non-susceptible pathogen who received amoxicillin-clavulanate or SOC. The primary outcome was clinical failure at 90 days. Secondary outcomes included time to failure, isolation of a resistant organism, and hospital length of stay. Fifty-nine patients met study inclusion: 26 received amoxicillin/clavulanate and 33 received SOC. Amoxicillin-clavulanate recipients did not have higher failure rates compared to SOC recipients. For patients requiring hospital admission, hospital length of stay was numerically shorter with amoxicillin-clavulanate. The frequency of amoxicillin-clavulanate and carbapenem-resistant organisms did not differ significantly between groups. Amoxicillin-clavulanate may be a useful alternative therapy for the treatment of ceftriaxone non-susceptible Enterobacterales UTIs.

Likelihood of Antimicrobial Resistance in Urinary E coli Isolates among US Female Patients with Recurrent vs Non-Recurrent Uncomplicated Urinary Tract Infection

OBJECTIVE

To assess the relative likelihood of antimicrobial resistance (AMR) and multi-drug resistance (MDR) among E coli isolates from outpatients with recurrent versus non-recurrent uncomplicated urinary tract infection (uUTI).

METHODS

In this retrospective observational US cohort study, female outpatients (≥12 years) with uUTI, positive E coli culture, and treated with ≥1 oral antibiotic within ±5 days of diagnosis were grouped into recurrent and non-recurrent uUTI cohorts per their UTI history (past 12 months). AMR to specific drug classes was evaluated at index. Univariable and multivariable logistic regression models estimated the likelihood of not-susceptible E coli isolates (AMR/MDR) among patients with recurrent uUTI versus non-recurrent uUTI.

RESULTS

Recurrent (N = 12,234) and non-recurrent (N = 68,033) uUTI cohorts had similar distributions (race, ethnicity, region). Patients with recurrent uUTI had a higher prevalence of E coli resistance to trimethoprim-sulfamethoxazole (21.8% vs 18.7%) and fluoroquinolones (14.2% vs 8.6%), and more isolates were extended-spectrum β-lactamase-producing (5.9% vs 4.1%) compared to non-recurrent uUTI patients. Patients with recurrent uUTI had a higher likelihood (odds ratio [95% confidence interval]) of any AMR (1.28 [1.22-1.34]), single drug-class resistance (1.18 [1.12-1.24]), and resistance to 2 (1.53 [1.41-1.67]) or ≥3 drug classes (1.70 [1.48-1.96]) (all P <.001).

CONCLUSION

This study delineated the likelihood of AMR and MDR among E coli isolates from patients with recurrent versus non-recurrent uUTI. While some treatment guidelines support empiric therapy in recurrent uUTI, the increased likelihood of resistance among these patients suggests that culture and susceptibility testing should be undertaken to inform recurrent uUTI treatment.

Multidrug resistance among uropathogenic clonal group A E. Coli isolates from Pakistani women with uncomplicated urinary tract infections

OBJECTIVE

Multi-drug resistance (MDR) has notably increased in community acquired uropathogens causing urinary tract infections (UTIs), predominantly Escherichia coli. Uropathogenic E. coli causes 80% of uncomplicated community acquired UTIs, particularly in pre-menopausal women. Considering this high prevalence and the potential to spread antimicrobial resistant genes, the current study was conducted to investigate the presence of clinically important strains of E. coli in Pakistani women having uncomplicated cystitis and pyelonephritis. Women belonging to low-income groups were exclusively included in the study. Seventy-four isolates from urine samples were processed, phylotyped, and screened for the presence of two Single Nucleotide Polymorphisms (SNPs) particularly associated with a clinically important clonal group A of E. coli (CgA) followed by antibiotic susceptibility testing and genome sequence analysis.

RESULTS

Phylogroup B2 was most prevalent in patients and 44% of isolates were positive for the presence of CgA specific SNPs in Fumarate hydratase and DNA gyrase subunit B genes. Antibiotic susceptibility testing showed widespread resistance to trimethoprim-sulfamethoxazole and extended-spectrum beta-lactamase production. The infection analysis revealed the phylogroup B2 to be more pathogenic as compared to the other groups. The genome sequence of E. coli strain U17 revealed genes encoding virulence, multidrug resistance, and host colonization mechanisms.

CONCLUSIONS

Our research findings not only validate the significant occurrence of multidrug-resistant clonal group A E. coli (CgA) in premenopausal Pakistani women suffering from cystitis and pyelonephritis but also reveal the presence of genes associated withvirulence, and drug efflux pumps. The detection of highly pathogenic, antimicrobial-resistant phylogroup B2 and CgA E. coli strains is likely to help in understanding the epidemiology of the pathogen and may ultimately help to reduce the impact of these strains on human health. Furthermore, the findings of this study will particularly help to reduce the prevalence of uncomplicated UTIs and the cost associated with their treatment in women belonging to low-income groups.

Determining a urinary-specific antibiogram and risk factors of trimethoprim/sulfamethoxazole, ciprofloxacin and multidrug resistance among Enterobacterales in primary care

BACKGROUND

Risk factors for ciprofloxacin or MDR in primary care urine specimens are not well defined.

OBJECTIVES

We created a primary care-specific antibiogram for Escherichia coli isolates from cases with complicated and uncomplicated urinary tract infection (UTI) and evaluated risk factors for ciprofloxacin, trimethoprim/sulfamethoxazole and MDR among Enterobacterales.

METHODS

We conducted a cross-sectional study to determine resistance and risk factors by collecting urine cultures from all patients (≥18 years) presenting with provider-suspected UTI at two primary care, safety-net clinics in Houston, TX, USA between November 2018 and March 2020.

RESULTS

Among 1262 cultures, 308 cultures grew 339 uropathogens. Patients with Enterobacterales (n = 199) were mostly female (93.5%) with a mean age of 48.5 years. E. coli was the predominant uropathogen isolated (n = 187/339; 55%) and had elevated trimethoprim/sulfamethoxazole (43.6%) and ciprofloxacin (29.5%) resistance, low nitrofurantoin (1.8%) resistance, and no fosfomycin resistance. Among E. coli, 10.6% were ESBL positive and 24.9% had MDR. Birth outside the U.S.A., prior (2 year) trimethoprim/sulfamethoxazole resistance, and diabetes mellitus were associated with trimethoprim/sulfamethoxazole resistance. Prior (60 day) fluoroquinolone use, prior ciprofloxacin resistance and both diabetes mellitus and hypertension were strongly associated with ciprofloxacin resistance. Prior fluoroquinolone use and a history of resistance to any studied antibiotic were associated with MDR, while pregnancy was protective.

CONCLUSIONS

We found elevated resistance to UTI-relevant antimicrobials and novel factors associated with resistance; these data can be incorporated into clinical decision tools to improve organism and drug concordance.

Oral gepotidacin versus nitrofurantoin in patients with uncomplicated urinary tract infection (EAGLE-2 and EAGLE-3): two randomised, controlled, double-blind, double-dummy, phase 3, non-inferiority trials

BACKGROUND

Gepotidacin is a novel, bactericidal, first-in-class triazaacenaphthylene antibiotic that inhibits bacterial DNA replication by a distinct mechanism of action and a unique binding site, providing well balanced inhibition of two type II topoisomerase enzymes. Oral gepotidacin is under investigation to treat uncomplicated urinary tract infections. We aimed to compare the efficacy and safety of oral gepotidacin with that of nitrofurantoin in adolescent and adult female individuals with uncomplicated urinary tract infections.

METHODS

EAGLE-2 and EAGLE-3 were phase 3, randomised, multicentre, double-blind, double-dummy, non-inferiority (10% margin) trials, in which patients were enrolled at 219 centres worldwide. Patients assigned female at birth, non-pregnant, aged 12 years or older, weighing 40 kg or more, with two or more symptoms of dysuria, frequency, urgency, or lower abdominal pain, and with evidence of urinary nitrite, pyuria, or both were eligible for inclusion. Patients were randomly assigned (1:1) centrally by interactive response technology to receive oral gepotidacin (1500 mg twice daily for 5 days) or oral nitrofurantoin (100 mg twice daily for 5 days), with randomisation stratified by age category and history of recurrent uncomplicated urinary tract infections. Patients, investigators, and the sponsor study team were masked to treatment assignment. The primary endpoint, therapeutic response (success or failure) at test-of-cure (ie, day 10-13), was evaluated in randomly assigned patients with nitrofurantoin-susceptible qualifying uropathogens (≥105 colony-forming units [CFU] per mL) and who received at least one dose of study treatment. Conforming to regulatory guidance, therapeutic success was defined as combined clinical success (ie, complete symptom resolution) and microbiological success (ie, reduction of qualifying uropathogens to <103 CFU/mL) without other systemic antimicrobial use. Safety analyses included patients who were randomly assigned and who received at least one dose of study treatment. The trials are registered with ClinicalTrials.gov, NCT04020341 (EAGLE-2) and NCT04187144 (EAGLE-3), and are completed.

FINDINGS

Studies were undertaken from Oct 17, 2019, to Nov 30, 2022 (EAGLE-2), and from April 23, 2020, to Dec 1, 2022 (EAGLE-3). 1680 patients in EAGLE-2 and 1731 patients in EAGLE-3 were screened for eligibility, of whom 1531 and 1605 were randomly assigned, respectively (767 in the gepotidacin group and 764 in the nitrofurantoin group in EAGLE-2, and 805 in the gepotidacin group and 800 in the nitrofurantoin group in EAGLE-3). After an interim analysis, which was prospectively agreed as a protocol amendment, both studies were stopped for efficacy. Thus, the primary analysis population included only patients who, at the time of the interim analysis data cutoff, had the opportunity to reach the test-of-cure visit or were known to not have attained therapeutic success before the test-of-cure visit. In EAGLE-2, 162 (50·6%) of 320 patients assigned gepotidacin and 135 (47·0%) of 287 patients assigned nitrofurantoin had therapeutic success (adjusted difference 4·3%, 95% CI -3·6 to 12·1). In EAGLE-3, 162 (58·5%) of 277 patients assigned gepotidacin and 115 (43·6%) of 264 patients assigned nitrofurantoin had therapeutic success (adjusted difference 14·6%, 95% CI 6·4 to 22·8). Gepotidacin was non-inferior to nitrofurantoin in both studies and superior to nitrofurantoin in EAGLE-3. The most common adverse event with gepotidacin was diarrhoea (observed in 111 [14%] of 766 patients in EAGLE-2 and in 147 [18%] of 804 patients in EAGLE-3), whereas the most common adverse event with nitrofurantoin was nausea (in 29 [4%] of 760 patients in EAGLE-2 and in 35 [4%] of 798 patients in EAGLE-3). Cases were mostly mild or moderate. No life-threatening or fatal events occurred.

INTERPRETATION

Gepotidacin is an efficacious oral antibiotic with acceptable safety and tolerability profiles. As a first-in-class investigational oral antibiotic with activity against common uropathogens, including clinically important drug-resistant phenotypes, gepotidacin has the potential to offer substantial benefit to patients.

FUNDING

GSK and the US Office of the Assistant Secretary for Preparedness and Response, Biomedical Advanced Research and Development Authority.

Prevalence, regional distribution, and trends of antimicrobial resistance among female outpatients with urine Klebsiella spp. isolates: a multicenter evaluation in the United States between 2011 and 2019

BACKGROUND

Antimicrobial resistance research in uncomplicated urinary tract infection typically focuses on the main causative pathogen, Escherichia coli; however, little is known about the antimicrobial resistance burden of Klebsiella species, which can also cause uncomplicated urinary tract infections. This retrospective cohort study assessed the prevalence and geographic distribution of antimicrobial resistance among Klebsiella species and antimicrobial resistance trends for K. pneumoniae in the United States (2011-2019).

METHODS

K. pneumoniae and K. oxytoca urine isolates (30-day, non-duplicate) among female outpatients (aged ≥ 12 years) with presumed uUTI at 304 centers in the United States were classified by resistance phenotype(s): not susceptible to nitrofurantoin, trimethoprim/sulfamethoxazole, or fluoroquinolone, extended-spectrum β-lactamase-positive/not susceptible; and multidrug-resistant based on ≥ 2 and ≥ 3 resistance phenotypes. Antimicrobial resistance prevalence by census division and age, as well as antimicrobial resistance trends over time for Klebsiella species, were assessed using generalized estimating equations.

RESULTS

270,552 Klebsiella species isolates were evaluated (250,719 K. pneumoniae; 19,833 K. oxytoca). The most frequent resistance phenotypes in 2019 were nitrofurantoin not susceptible (Klebsiella species: 54.0%; K. pneumoniae: 57.3%; K. oxytoca: 15.1%) and trimethoprim/sulfamethoxazole not susceptible (Klebsiella species: 10.4%; K. pneumoniae: 10.6%; K. oxytoca: 8.6%). Extended-spectrum β-lactamase-positive/not susceptible prevalence was 5.4%, 5.3%, and 6.8%, respectively. K. pneumoniae resistance phenotype prevalence varied (p < 0.0001) geographically and by age, and increased over time (except for the nitrofurantoin not susceptible phenotype, which was stable and > 50% throughout).

CONCLUSIONS

There is a high antimicrobial resistance prevalence and increasing antimicrobial resistance trends among K. pneumoniae isolates from female outpatients in the United States with presumed uncomplicated urinary tract infection. Awareness of K. pneumoniae antimicrobial resistance helps to optimize empiric uncomplicated urinary tract infection treatment.

Implementation of a multi-modal intervention adopting new technologies, clinical services, and feedback improves catheter-associated urinary tract infections

OBJECTIVES

Catheter-associated urinary tract infections (CAUTI) are a significant cause of morbidity and financial burden to healthcare systems. The aim of this study was to develop and implement a program designed to reduce Foley catheter use days and associated CAUTI rates.

METHODS

A retrospective evaluation of a multi-modal program aimed toward reducing Foley catheter use days and associated CAUTI rates across the Indiana University Health (IUH) system was conducted. IUH is comprised of 16 hospitals and 2,703 available beds. The program included the adoption of new technologies with evidence-based clinical training materials based on change management and feedback from clinicians. National Healthcare Safety Network Standardized Infection Ratio (SIR), Standardized Utilization Ratio (SUR), and Incidence Density Ratio (IDR) rates were assessed.

RESULTS

Implementation of the multi-modal program resulted in a significant reduction in SIR, SUR, and IDR in the post-implementation compared to the baseline periods.

CONCLUSIONS

Through CAUTI bundle workflow assessments, education, and interventions designed to standardize practice variation, the program was successfully implemented and resulted in a significant decrease in Foley Catheter use days, and associated CAUTI rates.

Predominance of multidrug-resistant bacteria causing urinary tract infections among symptomatic patients in East Africa: a call for action

Background

In low- and middle-income countries, antibiotics are often prescribed for patients with symptoms of urinary tract infections (UTIs) without microbiological confirmation. Inappropriate antibiotic use can contribute to antimicrobial resistance (AMR) and the selection of MDR bacteria. Data on antibiotic susceptibility of cultured bacteria are important in drafting empirical treatment guidelines and monitoring resistance trends, which can prevent the spread of AMR. In East Africa, antibiotic susceptibility data are sparse. To fill the gap, this study reports common microorganisms and their susceptibility patterns isolated from patients with UTI-like symptoms in Kenya, Tanzania and Uganda. Within each country, patients were recruited from three sites that were sociodemographically distinct and representative of different populations.

Methods

UTI was defined by the presence of >104 cfu/mL of one or two uropathogens in mid-stream urine samples. Identification of microorganisms was done using biochemical methods. Antimicrobial susceptibility testing was performed by the Kirby-Bauer disc diffusion assay. MDR bacteria were defined as isolates resistant to at least one agent in three or more classes of antimicrobial agents.

Results

Microbiologically confirmed UTI was observed in 2653 (35.0%) of the 7583 patients studied. The predominant bacteria were Escherichia coli (37.0%), Staphylococcus spp. (26.3%), Klebsiella spp. (5.8%) and Enterococcus spp. (5.5%). E. coli contributed 982 of the isolates, with an MDR proportion of 52.2%. Staphylococcus spp. contributed 697 of the isolates, with an MDR rate of 60.3%. The overall proportion of MDR bacteria (n = 1153) was 50.9%.

Conclusions

MDR bacteria are common causes of UTI in patients attending healthcare centres in East African countries, which emphasizes the need for investment in laboratory culture capacity and diagnostic algorithms to improve accuracy of diagnosis that will lead to appropriate antibiotic use to prevent and control AMR.

Treated, hospital-onset Clostridiodes difficile infection: An evaluation of predictors and feasibility of benchmarking comparing 2 risk-adjusted models among 265 hospitals

OBJECTIVES

To evaluate the incidence of a candidate definition of healthcare facility-onset, treated Clostridioides difficile (CD) infection (cHT-CDI) and to identify variables and best model fit of a risk-adjusted cHT-CDI metric using extractable electronic heath data.

METHODS

We analyzed 9,134,276 admissions from 265 hospitals during 2015-2020. The cHT-CDI events were defined based on the first positive laboratory final identification of CD after day 3 of hospitalization, accompanied by use of a CD drug. The generalized linear model method via negative binomial regression was used to identify predictors. Standardized infection ratios (SIRs) were calculated based on 2 risk-adjusted models: a simple model using descriptive variables and a complex model using descriptive variables and CD testing practices. The performance of each model was compared against cHT-CDI unadjusted rates.

RESULTS

The median rate of cHT-CDI events per 100 admissions was 0.134 (interquartile range, 0.023-0.243). Hospital variables associated with cHT-CDI included the following: higher community-onset CDI (CO-CDI) prevalence; highest-quartile length of stay; bed size; percentage of male patients; teaching hospitals; increased CD testing intensity; and CD testing prevalence. The complex model demonstrated better model performance and identified the most influential predictors: hospital-onset testing intensity and prevalence, CO-CDI rate, and community-onset testing intensity (negative correlation). Moreover, 78% of the hospitals ranked in the highest quartile based on raw rate shifted to lower percentiles when we applied the SIR from the complex model.

CONCLUSIONS

Hospital descriptors, aggregate patient characteristics, CO-CDI burden, and clinical testing practices significantly influence incidence of cHT-CDI. Benchmarking a cHT-CDI metric is feasible and should include facility and clinical variables.

Characterization of uropathogenic E. coli from various geographical locations in India

Objectives

Uropathogenic Escherichia coli (UPEC) is the most common causative agent of urinary tract infection, accounting for more than 80% of cases worldwide. This study presents data on prevalent serotypes, resistance profiles, and colonization-aiding virulence characteristics of UPEC from different geographical regions in India.

Methods

UPEC were serotyped through microtiter plate agglutination. Standard techniques were used to detect various virulence characteristics, i.e., biofilm formation (tissue culture plate method), siderophore production (screened on Chrome Azurol S agar and categorized with Csaky's and Arnow's methods), colicin release (agar overlay technique), gelatin hydrolysis (on gelatinase agar), and cell surface hydrophobicity (salt aggregation method). Antibiotic resistance profiles (against 20 antimicrobial agents) and extended-spectrum beta-lactamase (ESBL) were evaluated according to Clinical and Laboratory Standards Institute guidelines.

Results

UPEC strains exhibited very high drug resistance rates to most of the commonly used antimicrobial agents; the highest resistance rates were observed for ampicillin (63.4%), nalidixic acid (63.4%), and cefotaxime (62.1%). High rates of multi-drug resistance (63.36%), ESBL-production (34.1%), and carbapenem-resistance (25.0%) were detected in UPEC strains from all geographical regions of India. Hydrophobicity (61.2%), biofilm production (62.5%), and siderophore production (67.7%) were the most common virulence characteristics of UPEC isolates. Co-expression of virulence characteristics was common (69.8%) in UPEC strains.

Conclusion

UPEC strains with very high antimicrobial-resistance are in circulation in India, and have diverse serotypes and virulence characteristics.

Characteristics, costs, and outcomes associated with central-line-associated bloodstream infection and hospital-onset bacteremia and fungemia in US hospitals

OBJECTIVES

To compare characteristics and outcomes associated with central-line-associated bloodstream infections (CLABSIs) and electronic health record-determined hospital-onset bacteremia and fungemia (HOB) cases in hospitalized US adults.

METHODS

We conducted a retrospective observational study of patients in 41 acute-care hospitals. CLABSI cases were defined as those reported to the National Healthcare Safety Network (NHSN). HOB was defined as a positive blood culture with an eligible bloodstream organism collected during the hospital-onset period (ie, on or after day 4). We evaluated patient characteristics, other positive cultures (urine, respiratory, or skin and soft-tissue), and microorganisms in a cross-sectional analysis cohort. We explored adjusted patient outcomes [length of stay (LOS), hospital cost, and mortality] in a 1:5 case-matched cohort.

RESULTS

The cross-sectional analysis included 403 patients with NHSN-reportable CLABSIs and 1,574 with non-CLABSI HOB. A positive non-bloodstream culture with the same microorganism as in the bloodstream was reported in 9.2% of CLABSI patients and 32.0% of non-CLABSI HOB patients, most commonly urine or respiratory cultures. Coagulase-negative staphylococci and Enterobacteriaceae were the most common microorganisms in CLABSI and non-CLABSI HOB cases, respectively. In case-matched analyses, CLABSIs and non-CLABSI HOB, separately or combined, were associated with significantly longer LOS [difference, 12.1-17.4 days depending on intensive care unit (ICU) status], higher costs (by $25,207-$55,001 per admission), and a >3.5-fold increased risk of mortality in patients with an ICU encounter.

CONCLUSIONS

CLABSI and non-CLABSI HOB cases are associated with significant increases in morbidity, mortality, and cost. Our data may help inform prevention and management of bloodstream infections.

Increasing proportions of extended-spectrum β-lactamase-producing isolates among Escherichia coli from urine and bloodstream infections: results from a nationwide surveillance network, Finland, 2008 to 2019

BackgroundEscherichia coli is the leading cause of urinary tract infections (UTI) and bloodstream infections (BSI), and the emergence of antimicrobial resistance (AMR) in E. coli causes concern.AimTo investigate changes in the proportion of extended-spectrum β-lactamase (ESBL) producing isolates among E. coli isolated from urine and blood in Finland during 2008-2019.MethodsSusceptibility testing of 1,568,488 urine (90% female, 10% male) and 47,927 blood E. coli isolates (61% female, 39% male) from all Finnish clinical microbiology laboratories during 2008-2019 was performed according to guidelines from the Clinical and Laboratory Standard Institute during 2008-2010 and the European Committee on Antimicrobial Susceptibility Testing during 2011-2019. A binomial regression model with log link compared observed trends over time and by age group and sex.ResultsThe annual proportion of ESBL-producing E. coli isolates among E. coli from blood cultures increased from 2.4% (23/966) to 8.6% (190/2,197) among males (average annual increase 7.7%; 95% CI: 4.4-11.0%, p < 0.01) and from 1.6% (28/1,806) to 6.4% (207/3,218) among females (9.3%; 95% CI: 4.8-14.0%, p < 0.01). In urine cultures, the proportion of ESBL-producing E. coli isolates increased from 2.2% (239/10,806) to 7.2% (1,098/15,297) among males (8.8%; 95% CI: 6.5-11.3%, p < 0.01) and from 1.0% (1,045/108,390) to 3.1% (3,717/120,671) among females (8.6%; 95% CI: 6.3-11.0%, p < 0.01). A significant increase was observed within most age groups.ConclusionsConsidering the ageing population and their risk of E. coli BSI and UTI, the increase in the annual proportions of ESBL-producing E. coli is concerning, and these increasing trends should be carefully monitored.

Management of Pyogenic Liver Abscesses: Contemporary Strategies and Challenges

Pyogenic liver abscesses (PLAs) are a suppurative infection of the hepatic parenchyma responsible for significant morbidity and mortality. PLAs are categorized into a variety of mechanisms: (1) via the portal vein, (2) through the biliary tract, (3) via the hepatic artery, (4) from trauma, (5) contiguously via direct extension, and (6) cryptogenically. The pathogenesis of PLA, which informs treatment, can often be discerned based on host factors, clinical presentation, and causative microorganisms. The Streptococcus anginosus group, hypervirulent Klebsiella pneumoniae , and multidrug-resistant gram-negative pathogens have emerged as microbiologically challenging organisms to treat. The identification of hypervirulent K. pneumoniae should prompt for assessment for metastatic spread and consideration of prolonged antimicrobial treatment. Abdominal imaging is indispensable in characterizing PLAs and facilitating source control interventions. Source control remains the most critical aspect of PLA management, followed by antimicrobial therapy. Empiric antibiotics for PLAs are informed by the suspected etiology of PLA formation. Duration of antimicrobial therapy is individualized and dependent on multiple components, including the success of achieving source control, host factors, mechanism of PLA development, and the illness course of the individual-factoring in clinical, biochemical, and radiographic parameters.

Cephalosporins for the treatment of uncomplicated pyelonephritis: A systematic review

BACKGROUND

The 2011 Infectious Diseases Society of America and European Society of Clinical Microbiology and Infectious Diseases guidelines recommend ciprofloxacin or sulfamethoxazole-trimethoprim (SMX-TMP) as first-line agents to treat uncomplicated acute pyelonephritis (APN).

OBJECTIVE

With increasing antimicrobial resistance rates and recent changes in practice patterns, the objective of this systematic review was to describe the effectiveness of cephalosporins for uncomplicated APN in more recently published literature.

METHODS

Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were used for reporting. We searched PubMed, Embase, and Scopus for publications between January 2010 and September 2022. Eligible articles detailed patients with uncomplicated APN, treated with first- to fourth-generation cephalosporins, and identified a clinical, microbiological, or health care utilization outcome. Studies with more than 30% of complicated APN patients, non-English-language studies, case reports, case series, pharmacodynamic or pharmacokinetic studies, and in vitro laboratory or animal studies were excluded. Screening, review, and extraction were performed independently by 2 researchers, plus a third for conflict resolution. Critical appraisal of studies was performed using Joanna Briggs Institute checklists.

RESULTS

Eight studies met inclusion, including 5 cohort studies (62.5%), 2 randomized controlled trials (25%), and 1 nonrandomized experimental study (12.5%). Cephalosporins most used across the studies included cefazolin, cephalexin, cefuroxime, cefotaxime, cefdinir, cefditoren, and ceftriaxone. Outcomes assessed were diverse, including clinical or microbiological success and time to defervescence or symptom resolution. Cephalosporins displayed effectiveness for the treatment of acute uncomplicated APN regardless of study design or the presence of a comparison group. No trials reported inferiority of clinical treatment outcomes compared with a fluoroquinolone or SMX-TMP.

CONCLUSION

Cephalosporins may be viable treatment options for the management of uncomplicated APN.

Two Times Versus Four Times Daily Cephalexin Dosing for the Treatment of Uncomplicated Urinary Tract Infections in Females

Background

The current treatment guidelines of the Infectious Diseases Society of America recommend β-lactam antibiotics as alternative rather than first-line agents for the treatment of uncomplicated urinary tract infection (uUTI). Cephalexin is a commonly prescribed first-generation cephalosporin with excellent bioavailability and urinary penetration; however, little data exist to support optimal dosing for uUTI.

Methods

This retrospective multicenter cohort study included adult female patients who received 5 to 7 days of cephalexin for symptomatic uUTI with a cefazolin-susceptible urine culture. The primary objective was to compare uUTI treatment failure (eg, continued or recurrent symptoms within 30 days) between patients treated with cephalexin 500 mg twice daily (BID group) and 500 mg 4 times daily (QID group) in the outpatient setting. Secondary outcomes included time to treatment failure, reported adverse events within 7 days of treatment, and occurrence of Clostridioides difficile within 30 days of treatment.

Results

A total of 261 patients were included (BID, n = 173; QID, n = 88). Baseline characteristics were similar between the groups. Escherichia coli was the most commonly isolated pathogen (85.4%). There was no difference in treatment failure observed between the groups (BID 12.7% vs QID 17%, P = .343), including failure while undergoing therapy (BID 2.3% vs QID 5.7%, P = .438) or recurrence within 30 days (BID 10.4% vs QID 11.3%, P = .438). No differences in reported adverse events (BID 4.6% vs QID 5.6%, P = .103) were observed between groups.

Conclusions

Twice-daily cephalexin is as effective as 4-times-daily dosing for uUTI. A twice-daily dosing strategy may improve patient adherence.

Temporal dynamics of genetically heterogeneous extended-spectrum cephalosporin-resistant Escherichia coli bloodstream infections

Extended-spectrum cephalosporin-resistant Escherichia coli (ESC-R-Ec) is an urgent public health threat with sequence type clonal complex 131 (STc131), phylogroup B2 strains being particularly concerning as the dominant cause of ESC-R-Ec infections. To address the paucity of recent ESC-R-Ec molecular epidemiology data in the United States, we used whole-genome sequencing (WGS) to fully characterize a large cohort of invasive ESC-R-Ec at a tertiary care cancer center in Houston, Texas, collected from 2016 to 2020. During the study time frame, there were 1,154 index E. coli bloodstream infections (BSIs) of which 389 (33.7%) were ESC-R-Ec. Using time series analyses, we identified a temporal dynamic of ESC-R-Ec distinct from ESC-susceptible E. coli (ESC-S-Ec), with cases peaking in the last 6 months of the calendar year. WGS of 297 ESC-R-Ec strains revealed that while STc131 strains accounted for ~45% of total BSIs, the proportion of STc131 strains remained stable across the study time frame with infection peaks driven by genetically heterogeneous ESC-R-Ec clonal complexes. bla CTX-M variants accounted for most β-lactamases conferring the ESC-R phenotype (89%; 220/248 index ESC-R-Ec), and amplification of bla CTX-M genes was widely detected in ESC-R-Ec strains, particularly in carbapenem non-susceptible, recurrent BSI strains. Bla CTX-M-55 was significantly enriched within phylogroup A strains, and we identified bla CTX-M-55 plasmid-to-chromosome transmission occurring across non-B2 strains. Our data provide important information regarding the current molecular epidemiology of invasive ESC-R-Ec infections at a large tertiary care cancer center and provide novel insights into the genetic basis of observed temporal variability for these clinically important pathogens. IMPORTANCE Given that E. coli is the leading cause of worldwide ESC-R Enterobacterales infections, we sought to assess the current molecular epidemiology of ESC-R-Ec using a WGS analysis of many BSIs over a 5-year period. We identified fluctuating temporal dynamics of ESC-R-Ec infections, which have also recently been identified in other geographical regions such as Israel. Our WGS data allowed us to visualize the stable nature of STc131 over the study period and demonstrate a limited but genetically diverse group of ESC-R-Ec clonal complexes are detected during infection peaks. Additionally, we provide a widespread assessment of β-lactamase gene copy number in ESC-R-Ec infections and delineate mechanisms by which such amplifications are achieved in a diverse array of ESC-R-Ec strains. These data suggest that serious ESC-R-Ec infections are driven by a diverse array of strains in our cohort and impacted by environmental factors suggesting that community-based monitoring could inform novel preventative measures.

Clinical burden of invasive Escherichia coli disease among older adult patients treated in hospitals in the United States

BACKGROUND

Invasive extraintestinal pathogenic Escherichia coli disease (IED) can lead to severe outcomes, particularly among older adults. However, the clinical burden of IED in the U.S. has not been well characterized.

METHODS

IED encounters among patients ≥ 60 years old were identified using the PINC AI™ Healthcare Database (10/01/2015-03/31/2020) by either a positive E. coli culture in blood or another normally sterile body site and ≥ 1 sign of systemic inflammatory response syndrome or signs of sepsis, or a positive E. coli culture in urine with urinary tract infection and signs of sepsis. Medical resource utilization, clinical outcomes, and E. coli isolate characteristics were descriptively reported during the first IED encounter and during the following year (observation period).

RESULTS

Overall, 19,773 patients with IED were included (mean age: 76.8 years; 67.4% female; 78.5% with signs of sepsis). Most encounters involved community-onset IED (94.3%) and required hospitalization (96.5%; mean duration: 6.9 days), with 32.4% of patients being admitted to the intensive care unit (mean duration: 3.7 days). Most E. coli isolates were resistant to ≥ 1 antibiotic category (61.7%) and 34.4% were resistant to ≥ 3 antibiotic categories. Following their first IED encounter, 34.8% of patients were transferred to a skilled nursing/intermediate care facility, whereas 6.8% had died. During the observation period, 36.8% of patients were rehospitalized, 2.4% had IED recurrence, and in-hospital death increased to 10.9%.

CONCLUSIONS

IED is associated with substantial clinical burden at first encounter with considerable long-term consequences. Findings demonstrate the need for increased IED awareness and highlight potential benefits of prevention.

Clinical Risk Scores to Predict Nonsusceptibility to Trimethoprim-Sulfamethoxazole, Fluoroquinolone, Nitrofurantoin, and Third-Generation Cephalosporin Among Adult Outpatient Episodes of Complicated Urinary Tract Infection

Background

Clinical risk scores were developed to estimate the risk of adult outpatients having a complicated urinary tract infection (cUTI) that was nonsusceptible to trimethoprim-sulfamethoxazole (TMP-SMX), fluoroquinolone, nitrofurantoin, or third-generation cephalosporin (3-GC) based on variables available on clinical presentation.

Methods

A retrospective cohort study (1 December 2017-31 December 2020) was performed among adult members of Kaiser Permanente Southern California with an outpatient cUTI. Separate risk scores were developed for TMP-SMX, fluoroquinolone, nitrofurantoin, and 3-GC. The models were translated into risk scores to quantify the likelihood of nonsusceptibility based on the presence of final model covariates in a given cUTI outpatient.

Results

A total of 30 450 cUTIs (26 326 patients) met the study criteria. Rates of nonsusceptibility to TMP-SMX, fluoroquinolone, nitrofurantoin, and 3-GC were 37%, 20%, 27%, and 24%, respectively. Receipt of prior antibiotics was the most important predictor across all models. The risk of nonsusceptibility in the TMP-SMX model exceeded 20% in the absence of any risk factors, suggesting that empiric use of TMP-SMX may not be advisable. For fluoroquinolone, nitrofurantoin, and 3-GC, clinical risk scores of 10, 7, and 11 predicted a ≥20% estimated probability of nonsusceptibility in the models that included cumulative number of prior antibiotics at model entry. This finding suggests that caution should be used when considering these agents empirically in patients who have several risk factors present in a given model at presentation.

Conclusions

We developed high-performing parsimonious risk scores to facilitate empiric treatment selection for adult outpatients with cUTIs in the critical period between infection presentation and availability of susceptibility results.

Antimicrobial Resistance Patterns and Risk Factors Associated with ESBL-Producing and MDR Escherichia coli in Hospital and Environmental Settings in Lusaka, Zambia: Implications for One Health, Antimicrobial Stewardship and Surveillance Systems

Antimicrobial resistance (AMR) is a public health problem threatening human, animal, and environmental safety. This study assessed the AMR profiles and risk factors associated with Escherichia coli in hospital and environmental settings in Lusaka, Zambia. This cross-sectional study was conducted from April 2022 to August 2022 using 980 samples collected from clinical and environmental settings. Antimicrobial susceptibility testing was conducted using BD PhoenixTM 100. The data were analysed using SPSS version 26.0. Of the 980 samples, 51% were from environmental sources. Overall, 64.5% of the samples tested positive for E. coli, of which 52.5% were from clinical sources. Additionally, 31.8% were ESBL, of which 70.1% were clinical isolates. Of the 632 isolates, 48.3% were MDR. Most clinical isolates were resistant to ampicillin (83.4%), sulfamethoxazole/trimethoprim (73.8%), and ciprofloxacin (65.7%) while all environmental isolates were resistant to sulfamethoxazole/trimethoprim (100%) and some were resistant to levofloxacin (30.6%). The drivers of MDR in the tested isolates included pus (AOR = 4.6, CI: 1.9-11.3), male sex (AOR = 2.1, CI: 1.2-3.9), and water (AOR = 2.6, CI: 1.2-5.8). This study found that E. coli isolates were resistant to common antibiotics used in humans. The presence of MDR isolates is a public health concern and calls for vigorous infection prevention measures and surveillance to reduce AMR and its burdens.

Using evolutionary principles to make clinical decisions: a case series of urinary tract infections

The principles of evolutionary medicine have significant potential to be useful in a wide variety of clinical situations. Despite this, few demonstrations of clinical applications exist. To address this paucity, a case series applying evolutionary medicine principles to urinary tract infections, a common medical condition is presented. This series demonstrates how applying evolutionary medicine principles can be used to augment clinical decision-making.

Multidrug Resistance of Escherichia coli From Outpatient Uncomplicated Urinary Tract Infections in a Large United States Integrated Healthcare Organization

Background

Urinary tract infections (UTIs) cause significant disease and economic burden. Uncomplicated UTIs (uUTIs) occur in otherwise healthy individuals without underlying structural abnormalities, with uropathogenic Escherichia coli (UPEC) accounting for 80% of cases. With recent transitions in healthcare toward virtual visits, data on multidrug resistance (MDR) (resistant to ≥3 antibiotic classes) by care setting are needed to inform empiric treatment decision making.

Methods

We evaluated UPEC resistance over time by care setting (in-person vs virtual), in adults who received outpatient care for uUTI at Kaiser Permanente Southern California between January 2016 and December 2021.

Results

We included 174 185 individuals who had ≥1 UPEC uUTI (233 974 isolates) (92% female, 46% Hispanic, mean age 52 years [standard deviation 20]). Overall, prevalence of UPEC MDR decreased during the study period (13% to 12%) both in virtual and in-person settings (P for trend <.001). Resistance to penicillins overall (29%), coresistance to penicillins and trimethoprim-sulfamethoxazole (TMP-SMX) (12%), and MDR involving the 2 plus ≥1 antibiotic class were common (10%). Resistance to 1, 2, 3, and 4 antibiotic classes was found in 19%, 18%, 8%, and 4% of isolates, respectively; 1% were resistant to ≥5 antibiotic classes, and 50% were resistant to none. Similar resistance patterns were observed over time and by care setting.

Conclusions

We observed a slight decrease in both class-specific antimicrobial resistance and MDR of UPEC overall, most commonly involving penicillins and TMP-SMX. Resistance patterns were consistent over time and similar in both in-person and virtual settings. Virtual healthcare may expand access to UTI care.

In Vitro Activity of Omadacycline and Comparator Antibiotics against Extended-Spectrum Beta-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae Urinary Isolates

Limited oral antibiotic options exist for urinary tract infections (UTI) caused by ESBL-producing Enterobacterales. The aim of the study was to evaluate in vitro activity of omadacycline and comparator antibiotics against clinical ESBL-producing and non-ESBL-producing E. coli and K. pneumoniae urinary isolates. 102 isolates each of E. coli and K. pneumoniae were collected from clinical urine specimens in 2019. By design, an equal number of each species were included that tested positive and negative for ESBL production. Omadacycline MICs were determined using gradient test strips and compared to MICs of comparator antibiotics as determined by an automated broth microdilution system. Isolates were considered susceptible to omadacycline if the MIC was ≤4 µg/mL for each species. 54.9% of all ESBL-producing isolates were susceptible to omadacycline, but better susceptibility was observed for ESBL-producing E. coli (74.5%). Omadacycline MICs were 2-4 fold lower for E. coli and K. pneumoniae strains not producing ESBL. The omadacycline MIC 50 and 90 values were 4 and 16 µg/mL, respectively, for all isolates studied. 74.5% of all isolates were considered susceptible to omadacycline. MICs were generally lower for E. coli strains with MIC 50 and 90 values of 4 and 8 µg/mL, respectively (87.3% susceptible), compared with K. pneumoniae. Overall, the most active agents were omadacycline and nitrofurantoin, while other comparator antibiotics were less active. Omadacycline represents a promising oral antibiotic for treating UTI caused by ESBL-producing E. coli, particularly when resistance limits other oral options. Prospective, controlled clinical trials are needed to validate these in vitro results.

Unmet needs in uncomplicated urinary tract infection in the United States and Germany: a physician survey

BACKGROUND

Uncomplicated urinary tract infections (uUTIs/acute cystitis) are among the most common infections in women worldwide. There are differences in uUTI treatment guidelines between countries and understanding the needs of physicians in diverse healthcare systems is important for developing new treatments. We performed a survey of physicians in the United States (US) and Germany to understand their perceptions of, and management approaches to uUTI.

METHODS

This was a cross-sectional online survey of physicians in the US and Germany who were actively treating patients with uUTI (≥ 10 patients/month). Physicians were recruited via a specialist panel and the survey was piloted with 2 physicians (1 US, 1 Germany) prior to study commencement. Data were analyzed with descriptive statistics.

RESULTS

A total of 300 physicians were surveyed (n = 200 US, n = 100 Germany). Across countries and specialties, physicians estimated 16-43% of patients did not receive complete relief from initial therapy and 33-37% had recurrent infections. Urine culture and susceptibility testing was more common in the US and among urologists. The most commonly selected first-line therapy was trimethoprim-sulfamethoxazole in the US (76%) and fosfomycin in Germany (61%). Ciprofloxacin was the most selected following multiple treatment failures (51% US, 45% Germany). Overall, 35% of US and 45% of German physicians agreed with the statement "I feel there is a good selection of treatment options" and ≥ 50% felt that current treatments provided good symptom relief. More than 90% of physicians included symptom relief amongst their top 3 treatment goals. The overall impact of symptoms on patients' lives was rated "a great deal" by 51% of US and 38% of German physicians, increasing with each treatment failure. Most physicians (> 80%) agreed that antimicrobial resistance (AMR) is serious, but fewer (56% US, 46% Germany) had a high level of confidence in their knowledge of AMR.

CONCLUSIONS

Treatment goals for uUTI were similar in the US and Germany, although with nuances to disease management approaches. Physicians recognized that treatment failures have a significant impact on patients' lives and that AMR is a serious problem, though many did not have confidence in their own knowledge of AMR.

A geospatial approach to identify patterns of antibiotic susceptibility at a neighborhood level in Wisconsin, United States

The global threat of antimicrobial resistance (AMR) varies regionally. This study explores whether geospatial analysis and data visualization methods detect both clinically and statistically significant variations in antibiotic susceptibility rates at a neighborhood level. This observational multicenter geospatial study collected 10 years of patient-level antibiotic susceptibility data and patient addresses from three regionally distinct Wisconsin health systems (UW Health, Fort HealthCare, Marshfield Clinic Health System [MCHS]). We included the initial Escherichia coli isolate per patient per year per sample source with a patient address in Wisconsin (N = 100,176). Isolates from U.S. Census Block Groups with less than 30 isolates were excluded (n = 13,709), resulting in 86,467 E. coli isolates. The primary study outcomes were the results of Moran's I spatial autocorrelation analyses to quantify antibiotic susceptibility as spatially dispersed, randomly distributed, or clustered by a range of - 1 to + 1, and the detection of statistically significant local hot (high susceptibility) and cold spots (low susceptibility) for variations in antibiotic susceptibility by U.S. Census Block Group. UW Health isolates collected represented greater isolate geographic density (n = 36,279 E. coli, 389 = blocks, 2009-2018), compared to Fort HealthCare (n = 5110 isolates, 48 = blocks, 2012-2018) and MCHS (45,078 isolates, 480 blocks, 2009-2018). Choropleth maps enabled a spatial AMR data visualization. A positive spatially-clustered pattern was identified from the UW Health data for ciprofloxacin (Moran's I = 0.096, p = 0.005) and trimethoprim/sulfamethoxazole susceptibility (Moran's I = 0.180, p < 0.001). Fort HealthCare and MCHS distributions were likely random. At the local level, we identified hot and cold spots at all three health systems (90%, 95%, and 99% CIs). AMR spatial clustering was observed in urban areas but not rural areas. Unique identification of AMR hot spots at the Block Group level provides a foundation for future analyses and hypotheses. Clinically meaningful differences in AMR could inform clinical decision support tools and warrants further investigation for informing therapy options.

Risk-factor analysis for extended-spectrum beta-lactamase-producing Enterobacterales colonization or infection: Evaluation of a novel approach to assess local prevalence as a risk factor

OBJECTIVE

To explore an approach to identify the risk of local prevalence of extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E) on ESBL-E colonization or infection and to reassess known risk factors.

DESIGN

Case-control study.

SETTING

Johns Hopkins Health System emergency departments (EDs) in the Baltimore-Washington, DC, region.

PATIENTS

Patients aged ≥18 years with a culture growing Enterobacterales between April 2019 and December 2021. Cases had a culture growing an ESBL-E.

METHODS

Addresses were linked to Census Block Groups and placed into communities using a clustering algorithm. Prevalence in each community was estimated using the proportion of ESBL-E among Enterobacterales isolates. Logistic regression was used to determine risk factors for ESBL-E colonization or infection.

RESULTS

ESBL-E were detected in 1,167 of 11,224 patients (10.4%). Risk factors included a history of ESBL-E in the prior 6 months (aOR, 20.67; 95% CI, 13.71-31.18), exposure to a skilled nursing or long-term care facility (aOR, 1.64; 95% CI, 1.37-1.96), exposure to a third-generation cephalosporin (aOR, 1.79; 95% CI, 1.46-2.19), exposure to a carbapenem (aOR, 2.31; 95% CI, 1.68-3.18), or exposure to a trimethoprim-sulfamethoxazole (aOR, 1.54; 95% CI, 1.06-2.25) within the prior 6 months. Patients were at lower risk if their community had a prevalence <25th percentile in the prior 3 months (aOR, 0.83; 95% CI, 0.71-0.98), 6 months (aOR, 0.83; 95% CI, 0.71-0.98), or 12 months (aOR, 0.81; 95% CI, 0.68-0.95). There was no association between being in a community in the >75th percentile and the outcome.

CONCLUSIONS

This method of defining the local prevalence of ESBL-E may partially capture differences in the likelihood of a patient having an ESBL-E.

High prevalence of β-lactam and fluoroquinolone resistance in various phylotypes of Escherichia coli isolates from urinary tract infections in Jiroft city, Iran

BACKGROUND

Urinary tract infection (UTI) is one of the most prevalent infectious diseases with worldwide health threatening. Antimicrobial resistant strains of Escherichia coli (E. coli) are a common cause of UTI which were identified as a treatment challenge. This study aimed to assay the prevalence of common β-lactam resistance genes including bla_TEM, bla_SHV, bla_CTX-M and bla_CMY and phenotypic resistance to commonly used β-lactam and fluoroquinolone antibiotics in UTIs. These factors were evaluated in various phylogenetic groups (phylotypes) of E. coli isolates. Real-time PCR was applied to detect β-lactam resistance genes and conventional PCR was used to determine the phylotypes. Phenotypic resistance against β-lactams (ceftazidime, cefotaxime, aztreonam and ceftriaxone) and fluoroquinolones (ciprofloxacin) were identified by the disc diffusion technique. The ability of extended spectrum β-lactamases (ESBLs) production in E. coli isolates was detected using the combined disc diffusion method.

RESULTS

The prevalence of resistance genes were 89.6% for bla_TEM, 44.3% for bla_CTX-M, 6.6% for bla_SHV and 0.9% for bla_CMY. The two high prevalent phylotypes were B2 (29.2%) and D (17.9%) followed by E (14.1%), F (9.4%), C (6.6%) and 10.3% of isolates were unknown in phylotyping. Disc diffusion results showed high prevalence of antibiotic resistance to cefotaxime (88.6%), aztreonam (83%), ceftireaxon (77.3%), ceftazidime (76.4%) and ciprofloxacin (55.6%). Totally, 52.8% of isolates were found as phenotypical ESBL-producers.

CONCLUSIONS

This study's results confirmed an explosion of antibiotic resistance amongst E. coli isolates from UTI against β-lactams and fluoroquinolones. Findings explain the necessity of deep changes in quantity and quality of drug resistance diagnosis and antibiotic therapy strategies. More studies are suggested to better and confident evaluations.

Antimicrobial Activity of Tebipenem and Comparators against Enterobacterales from diverse Outpatient Centers and Nursing Homes in the United States

INTRODUCTION

Tebipenem is a potential option for the treatment of a range of infections because of its oral dosing coupled with the safety profile of the β-lactam antimicrobial class.

OBJECTIVES

To evaluate tebipenem in vitro activity against a challenge set of clinical Enterobacterales collected from outpatient and community settings.

METHODS

618 Enterobacterales isolates were submitted by 11 geographically dispersed U.S medical centers that processed cultures from affiliated outpatient centers in 2022. Susceptibility tests for tebipenem and comparator agents were performed by broth microdilution. Extended-spectrum-β-lactamase (ESBL)-like isolates were identified phenotypically. Multidrug-resistant isolates were non-susceptible to ≥1 agent in ≥3 antimicrobial classes. Genotypic testing (CarbaR) was conducted on select isolates.

RESULTS

Isolates (59% Escherichia coli) were recovered from patients seen predominantly in urology/nephrology (24%), nursing home/long-term care (21%), and ambulatory/primary care (21%) clinics. Comparator agent susceptibility rates against all isolates were as follows: levofloxacin (67.5%), amoxicillin/clavulanate (73.6%), cefixime (70.4%), cefpodoxime (70%), cephalexin (61.7%), ceftriaxone (74.4%), cefazolin (63.8%), ertapenem (97.6%), meropenem (99.7%), nitrofurantoin (64.9%), and sulfamethoxazole/trimethoprim (70.9%). Overall, 90.3% (558/619) of isolates were inhibited at a tebipenem MIC of ≤0.125 mg/L (MIC_50/90, 0.016/0.125 mg/L), including 85.7% inhibition of ESBL-phenotype isolates (n=161; MIC_50/90, 0.03/0.25 mg/L), 86.3% of levofloxacin and sulfamethoxazole/trimethoprim co-resistant isolates (n=95; MIC_50/90, 0.016/0.25 mg/L) and 84.3% of multidrug-resistant isolates (n = 172; MIC_50/90, 0.03/0.25 mg/L). Carbapenemase genes were observed in 2 ESBL-phenotype isolates with a tebipenem MIC of ≥0.5 mg/L.

CONCLUSION

Relative to common oral comparators, these data demonstrate excellent tebipenem in vitro activity against Enterobacterales isolated from patients receiving care in outpatient settings, including urology clinics and nursing homes.

Antimicrobial Resistance in Urinary Tract Infections: Is There an Issue and Does It Matter?

Antimicrobial resistance (AMR) has increased substantially among community-acquired uropathogens that cause urinary tract infections (UTI), limiting the availability of effective oral antibiotic treatments. This review includes coverage of an expert-led Learning Lounge, symposium session, and several poster presentations, that took place between 20th–22nd October 2022 as part of IDWeek2022 in Washington, D.C., USA. An immersive Learning Lounge, sponsored by GSK, opened with Keith Kaye, Department of Medicine, Rutgers–Robert Wood Johnson Medical School, New Brunswick, New Jersey, USA, who illuminated the concerns of AMR in community-acquired UTIs, delivering contemporary surveillance data, and outlined how in vitro data may translate into practical advice. This led fittingly to Erin McCreary, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, Pennsylvania, USA, who enquired whether enough is being done in clinical practice regarding community-acquired infections, highlighting the importance of antimicrobial stewardship (AMS), and galvanising the audience to adapt healthcare settings to the changing landscape. The scientific programme also included three data-rich posters that showcased Kaye’s surveillance data on Escherichia coli and Klebsiella pneumoniae co-resistance, along with the geographical distribution of K. pneumoniae. An insightful poster by Claire Trennery, Value Evidence Outcomes, GSK, Brentford, UK, considered the patient perspective of UTI symptoms in defining antibiotic treatment success, and two posters presented by Rodrigo Mendes, JMI Laboratories, North Liberty, Iowa, USA, examined in vitro global surveillance data of emerging antimicrobial treatments.

Contemporary Evaluation of Tebipenem In Vitro Activity against Enterobacterales Clinical Isolates Causing Urinary Tract Infections in US Medical Centers (2019-2020)

Tebipenem pivoxil is an oral broad-spectrum carbapenem. This study evaluated the activity of tebipenem and comparators against UTI Enterobacterales from US hospitals (2019-2020). 3,576 Enterobacterales causing UTI in 52 centers in 9 US Census Divisions were included. Susceptibility testing followed the CLSI broth microdilution method. Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis with an MIC of ≥2 μg/mL for ceftazidime, ceftriaxone, and/or aztreonam were designated ESBL. Isolates were also grouped based on MDR phenotype. Tebipenem, meropenem, and ertapenem had MIC₉₀ against Enterobacterales of 0.06 μg/mL, 0.06 μg/mL and 0.03 μg/mL, respectively. Low susceptibility results for aztreonam (87.1% susceptible), cefazidime (88.1%), ceftriaxone (84.8%), and other agents were observed. Tebipenem and ertapenem were equally potent (MIC₉₀, 0.015 to 0.03 μg/mL) against E. coli and K. pneumoniae, whereas ertapenem showed an MIC 8-fold lower than tebipenem against P. mirabilis. Oral agents, such as amoxicillin-clavulanate, levofloxacin, and trimethoprim-sulfamethoxazole, showed elevated nonsusceptibility rates in the Middle Atlantic region (26, 45, 47, and 41%, respectively). ESBL prevalence varied from 7% to 16%, except in the Middle Atlantic region (42%). The carbapenems were active against ESBL and MDR isolates (93.7 to 96.8% susceptible). Elevated rates of ESBL in UTI pathogens in US hospitals were noted as well as a uniform in vitro potency (MIC₉₀) of tebipenem and the intravenous carbapenems, regardless of phenotype. IMPORTANCE The occurrence of urinary-tract Enterobacterales pathogens producing ESBL enzymes in community and nosocomial settings continues to increase, as does the coresistance to fluoroquinolones, trimethoprim-sulfamethoxazole and nitrofurantoin often exhibited by these pathogens. This scenario complicates the clinical empirical and guided management of UTI by precluding the use of oral and many intravenous options. Oral options appear compromised even among some ESBL-negative isolates, against which the use of parenteral agents may be required. In addition, the interregional variability of susceptibility results of US UTI pathogens provides a less predictable susceptibility pattern to inform empirical treatment decisions. This study evaluated the in vitro activity of tebipenem against contemporary uropathogens, including those resistant to currently available oral options.

Dynamic Periodicity of Extended-Spectrum Cephalosporin Resistant Bloodstream Escherichia coli Infections Driven by Non-CC131 Strains

Extended-spectrum cephalosporin resistant (ESC-R) Escherichia coli (ESC-R- Ec ) is an urgent public health threat with clonal complex (CC) 131, phylogroup B2 strains being particularly concerning as the dominant cause of ESC-R- Ec infections. To address the paucity of recent ESC-R- Ec molecular epidemiology data in the United States (US), we used whole genome sequencing (WGS) to fully characterize a large cohort of invasive ESC-R- Ec at a tertiary care cancer center in Houston, Texas collected from 2016-2020. During the study timeframe, there were 1154 index E. coli bloodstream infections (BSIs) of which 389 (33.7%) were ESC-R. Using time series analyses, we identified a temporal dynamic of ESC-R E. coli BSIs ( Ec -BSIs), distinct from ESC-susceptible Ec -BSIs, with cases peaking in the last 6 months of the calendar year. WGS of 297 ESC-R Ec -BSI strains revealed that while CC131 strains accounted for ∼45% of total infections, the proportion of CC131 strains remained stable across the time-period, and infection peaks were driven by genetically diverse, non-CC131 isolates. Bla _CTX-M variants accounted for most β-lactamases conferring the ESC-R phenotype (89%; 220/248 index ESC-R Ec -BSIs), and amplification of bla _CTX-M genes was widely detected in ESC-R Ec -BSI strains, particularly in carbapenem non-susceptible strains and in strains causing recurrent BSIs. Bla _{CTX- M-55} was significantly enriched within phylogroup A strains, and we identified bla _CTX-M-55 plasmid-to-chromosome transmission occurring across non-B2 strains. Our data provide important information regarding the current molecular epidemiology of invasive ESC-R E. coli and provide novel insights into the genetic basis of observed temporal variability for these clinically important pathogens.

IMPORTANCE

Given that E. coli is the leading cause of ESC-R Enterobacterales infection, we sought to assess the current molecular epidemiology of ESC-R- Ec using a WGS based analysis of many BSIs over a several year period. We identified a clear temporal dynamic of ESC-R- Ec infections, which has also recently been identified in other geographical regions such as Israel. Our WGS data allowed us to visualize the stable nature of CC131 over the study period and demonstrate that non-CC131 strains drove the infection peaks. Additionally, we provide the first widespread assessment of β-lactamase gene copy number in ESC-R- Ec infections and delineate mechanisms by which such amplifications are achieved in a diverse array of ESC-R- Ec strains. These data suggest that even for a tertiary care center, serious ESC-R- Ec infections are driven by a diverse array of strains and impacted by environmental factors suggesting that community-based monitoring could inform novel preventative measures.

Impact of a Statewide Livestock Antibiotic Use Policy on Resistance in Human Urine Escherichia coli Isolates: A Synthetic Control Analysis

BACKGROUND

On 1 January 2018, California implemented Senate Bill 27 (SB27), banning, for the first time in the United States, routine preventive use of antibiotics in food-animal production and any antibiotic use without a veterinarian's prescription.

OBJECTIVES

Our objective was to assess whether SB27 was associated with decreased antimicrobial resistance among E. coli isolated from human urine.

METHODS

We used U.S. nationwide monthly state-level data from BD Insights Research Database (Becton, Dickinson, and Co.) spanning 1 January 2013 to 30 June 2021 on antibiotic-resistance patterns of 30-d nonduplicate E. coli isolated from urine. Tested antibiotic classes included aminoglycosides, extended-spectrum cephalosporins (ESC), fluoroquinolones, and tetracyclines. Counts of tested and not-susceptible (resistant and intermediate, hereafter resistant) urine isolates were available by sex, age group (<65, 65+ year), month, and state. We applied a synthetic control approach to estimate the causal effect of SB27 on resistance patterns. Our approach created a synthetic California based on a composite of other states without the policy change and contrasted its counterfactual postpolicy trends with the observed postpolicy trends in California.

FINDINGS

We included 7.1 million E. coli urine isolates, 90% among women, across 33 states. From 2013 to 2017, the median (interquartile range) resistance percentages in California were 11.9% (7.4, 17.6), 13.8% (5.8, 20.0), 24.6% (9.6, 36.4), 7.9% (2.1, 13.1), for aminoglycosides, ESC, fluoroquinolones, and tetracyclines, respectively. SB27 was associated with a 7.1% reduction in ESC resistance (p-value for joint null: <0.01), but no change in resistance to aminoglycosides, fluoroquinolones, or tetracyclines.

DISCUSSION

Further research is needed to determine the role of SB27 in the observed reduction in ESC resistance E. coli in human populations, particularly as additional states implement similar legislation. https://doi.org/10.1289/EHP11221.

Sulopenem or Ciprofloxacin for the Treatment of Uncomplicated Urinary Tract Infections in Women: A Phase 3, Randomized Trial

BACKGROUND

There are limited treatment options for uncomplicated urinary tract infection (uUTI) caused by resistant pathogens. Sulopenem etzadroxil/probenecid (sulopenem) is an oral thiopenem antibiotic active against multidrug-resistant pathogens that cause uUTIs.

METHODS

Patients with uUTI were randomized to 5 days of sulopenem or 3 days of ciprofloxacin. The primary endpoint was overall success, defined as both clinical and microbiologic response at day 12. In patients with ciprofloxacin-nonsusceptible baseline pathogens, sulopenem was compared for superiority over ciprofloxacin; in patients with ciprofloxacin-susceptible pathogens, the agents were compared for noninferiority. Using prespecified hierarchical statistical testing, the primary endpoint was tested in the combined population if either superiority or noninferiority was declared in the nonsusceptible or susceptible population, respectively.

RESULTS

In the nonsusceptible population, sulopenem was superior to ciprofloxacin, 62.6% vs 36.0% (difference, 26.6%; 95% confidence interval [CI], 15.1 to 7.4; P <.001). In the susceptible population, sulopenem was not noninferior to ciprofloxacin, 66.8% vs 78.6% (difference, -11.8%; 95% CI, -18.0 to 5.6). The difference was driven by a higher rate of asymptomatic bacteriuria (ASB) post-treatment in patients on sulopenem. In the combined analysis, sulopenem was noninferior to ciprofloxacin, 65.6% vs 67.9% (difference, -2.3%; 95% CI, -7.9 to 3.3). Diarrhea occurred more frequently with sulopenem (12.4% vs 2.5%).

CONCLUSIONS

Sulopenem was noninferior to ciprofloxacin in the treatment of uUTIs. Sulopenem was superior to ciprofloxacin in patients with uUTIs due to ciprofloxacin-nonsusceptible pathogens. Sulopenem was not noninferior in patients with ciprofloxacin-susceptible pathogens, driven largely by a lower rate of ASB in those who received ciprofloxacin.

CLINICAL TRIAL REGISTRATION

NCT03354598.

How I manage bacterial prostatitis

BACKGROUND

Bacterial prostatitis is a highly prevalent infection responsible for significant morbidity among men. The diagnosis and treatment for bacterial prostatitis remains complicated. The difficulty in diagnosis is in part owing to the paucity of high-quality evidence that guides a clinician's interpretation of patients' history, physical examination, and laboratory findings. Treatment is challenging because of the few antimicrobials capable of prostate penetration, growing antimicrobial resistance limiting effective treatment options, and the high risk of recurrence.

OBJECTIVES

We aimed to provide a useful resource for clinicians in effectively diagnosing and managing acute bacterial prostatitis (ABP) and chronic bacterial prostatitis (CBP).

SOURCES

A PubMed literature search on prostatitis was performed with no restrictions on publication date.

CONTENT

The epidemiology, pathophysiology, diagnosis, and treatment for ABP and CBP are explored using a clinical vignette as relevant context.

IMPLICATIONS

Bacterial prostatitis can be diagnosed through a focused history and microbiological investigations. The Meares-Stamey 4-glass test or modified 2-glass test can help confirm the diagnosis if uncertainty exists. Typical uropathogens are common contributors to bacterial prostatitis but there is growing interest in exploring the role atypical and traditional non-pathogenic organisms may have. Fluoroquinolones remain first-line therapy, followed by trimethoprim-sulfamethoxazole (TMP-SMX) or doxycycline if the pathogen is susceptible. Fosfomycin has emerged as a repurposed and useful agent because of the increasing incidence of multidrug-resistant pathogens. Selection of appropriate antimicrobial regimens can be challenging and is dependent on the host, chronicity of symptoms, uropathogens' susceptibilities, antimicrobials' side effect profile, and the presence of prostatic abscesses or calcifications. ABP can typically be treated similar to other complicated urinary tract infections. However, CBP requires prolonged therapy, with a minimum of 4 weeks and up to 12 weeks of therapy.

Older patient age and prior antimicrobial use strongly predict antimicrobial resistance in Escherichia coli isolates recovered from urinary tract infections among female outpatients

BACKGROUND

Increasing prevalence of antimicrobial resistance (AMR), including multidrug resistance (MDR), among Escherichia coli (E. coli) makes treatment of uncomplicated urinary tract infection (uUTI) difficult. We assessed risk factors for fluoroquinolone (FQ)-not-susceptible (NS) and MDR E. coli among US female outpatients.

METHODS

This retrospective cohort study utilized data from female outpatients aged ≥ 12 years with E. coli positive urine culture and oral antimicrobial prescription ± 1 day from index. We assessed patient-level factors within 90 and 91-360 days prior to index as predictors of FQ NS (intermediate/resistant) and MDR (NS to ≥ 1 drug across ≥ 3 classes) E. coli: age, prior oral antimicrobial dispensing, prior AMR phenotypes, prior urine culture, and prior hospitalization.

RESULTS

Among 1,858 outpatients with urine-isolated E. coli, 369 (19.9%) had FQ NS and 59 (3.2%) had MDR isolates. After multivariable adjustment, independent risk factors (p < 0.03) for FQ NS E. coli were older age, prior FQ NS isolates, prior dispensing of FQ, and dispensing of any oral antibiotic. Independent risk factors (p < 0.02) for MDR were prior extended-spectrum β-lactamase-producing isolates (ESBL+), prior FQ dispensing, and prior oral antibiotic dispensing.

CONCLUSIONS

In women with uUTI due to E. coli, prior dispensing of FQ or any oral antibiotic within 90 days predicted FQ NS and MDR urine E. coli. Prior urine culture with FQ NS isolates and older age were predictive of FQ NS E. coli. Prior ESBL+ was predictive of MDR E. coli. These data could help identify patients at risk for AMR E. coli and inform empiric prescribing.

A one-year genomic investigation of Escherichia coli epidemiology and nosocomial spread at a large US healthcare network

BACKGROUND

Extra-intestinal pathogenic Escherichia coli (ExPEC) are a leading cause of bloodstream and urinary tract infections worldwide. Over the last two decades, increased rates of antibiotic resistance in E. coli have been reported, further complicating treatment. Worryingly, specific lineages expressing extended-spectrum β-lactamases (ESBLs) and fluoroquinolone resistance have proliferated and are now considered a serious threat. Obtaining contemporary information on the epidemiology and prevalence of these circulating lineages is critical for containing their spread globally and within the clinic.

METHODS

Whole-genome sequencing (WGS), phylogenetic analysis, and antibiotic susceptibility testing were performed for a complete set of 2075 E. coli clinical isolates collected from 1776 patients at a large tertiary healthcare network in the USA between October 2019 and September 2020.

RESULTS

The isolates represented two main phylogenetic groups, B2 and D, with six lineages accounting for 53% of strains: ST-69, ST-73, ST-95, ST-131, ST-127, and ST-1193. Twenty-seven percent of the primary isolates were multidrug resistant (MDR) and 5% carried an ESBL gene. Importantly, 74% of the ESBL-E.coli were co-resistant to fluoroquinolones and mostly belonged to pandemic ST-131 and emerging ST-1193. SNP-based detection of possible outbreaks identified 95 potential transmission clusters totaling 258 isolates (12% of the whole population) from ≥ 2 patients. While the proportion of MDR isolates was enriched in the set of putative transmission isolates compared to sporadic infections (35 vs 27%, p = 0.007), a large fraction (61%) of the predicted outbreaks (including the largest cluster grouping isolates from 12 patients) were caused by the transmission of non-MDR clones.

CONCLUSION

By coupling in-depth genomic characterization with a complete sampling of clinical isolates for a full year, this study provides a rare and contemporary survey on the epidemiology and spread of E. coli in a large US healthcare network. While surveillance and infection control efforts often focus on ESBL and MDR lineages, our findings reveal that non-MDR isolates represent a large burden of infections, including those of predicted nosocomial origins. This increased awareness is key for implementing effective WGS-based surveillance as a routine technology for infection control.

The Antimicrobial Resistance (AMR) Rates of Uropathogens in a Rural Western African Area-A Retrospective Single-Center Study from Kpando, Ghana

Little is known about the antimicrobial resistance (AMR) status of uropathogens in Western Africa. We performed a retrospective evaluation of urine cultures collected from the rural Margret Marquart Catholic Hospital, Kpando, Ghana during the time period from October 2019−December 2021. Urine samples from 348 patients (median age 40 years, 52.6% male) were examined. Of these, 125 (35.9%) showed either fungal or bacterial growth, including Escherichia coli in 48 (38.4%), Candida species (spp.) in 29 (23.2%), Klebsiella spp. in 27 (21.6%), Proteus spp. in 12 (9.6%), Citrobacter spp. in 10 (8.0%), Salmonella spp. in 4 (3.2%), Staphylococcus spp. in 3 (2.4%), and Pseudomonas spp. in 2 (1.6%) cases. Two bacterial spp. were detected in 7 samples (5.6%). Antibiotic susceptibility testing showed resistance to a mean 8.6 out of 11 tested antibiotics per patient. Significant predictors (p < 0.05) of bacterial growth were age (OR 1.03), female sex (OR 3.84), and the number of pus cells (OR 1.05) and epithelial cells (OR 1.07) in urine microscopy. We observed an alarmingly high AMR rate among the uropathogens detected, even to reserve antibiotics. A similar resistance profile can be expected in West African patients living in high-income countries. These observations warrant the implementation of restrictive antibiotic protocols, together with the expansion of urine culture testing capacities, improvement of documentation and reporting of AMR rates, and continued research and development of new antibiotic therapies in order to stem the progression of AMR in this West African region.

Antimicrobial betalains

Betalains are nitrogen-containing plant pigments that can be red-violet (betacyanins) or yellow-orange (betaxanthins), currently employed as natural colourants in the food and cosmetic sectors. Betalains exhibit antimicrobial activity against a broad spectrum of microbes including multidrug-resistant bacteria, as well as single-species and dual-species biofilm-producing bacteria, which is highly significant given the current antimicrobial resistance issue reported by The World Health Organization. Research demonstrating antiviral activity against dengue virus, in silico studies including SARS-CoV-2, and anti-fungal effects of betalains highlight the diversity of their antimicrobial properties. Though limited in vivo studies have been conducted, antimalarial and anti-infective activities of betacyanin have been observed in living infection models. Cellular mechanisms of antimicrobial activity of betalains are yet unknown; however existing research has laid the framework for a potentially novel antimicrobial agent. This review covers an overview of betalains as antimicrobial agents and discussions to fully exploit their potential as therapeutic agents to treat infectious diseases.

Economic burden of antibiotic-not-susceptible isolates in uncomplicated urinary tract infection: Analysis of a US integrated delivery network database

Background

Uncomplicated urinary tract infections (uUTIs) are one of the most common bacterial infections in the United States (US). Contemporary data are important for understanding the health economic impact of antimicrobial-resistant uUTIs. We compared the economic burden among patients with uUTI isolates susceptible or not-susceptible to the initial antibiotic prescription.

Methods

This retrospective cohort study utilized electronic health record data (1 July 2016–31 March 2020) from a large Mid-Atlantic US integrated delivery network database. Patients were females aged ≥ 12 years with a uUTI, who received oral antibiotic treatment and had ≥ 1 urine culture within ± 5 days of diagnosis. The primary outcome was the difference in healthcare resource use and costs (all-cause, urinary tract infection [UTI]-related) among patients with susceptible versus not-susceptible isolates during the 6 months after the index uUTI diagnosis. Secondary outcomes included: pharmacy costs, hospital admissions and emergency department visits, as well as the probability of uUTI progressing to complicated UTI (cUTI) between patients with susceptible and not-susceptible isolates. Patient outcomes were compared using 1:1 propensity score matching. Winsorized costs were adjusted to 2020 quarter 1 US dollars ($).

Results

A total of 2565 patients were eligible for analysis. The propensity score-matched sample comprised 2018 patients, with an average age of 44.0 and 41.0 years for the susceptible and not-susceptible populations, respectively. In the 6 months post-index uUTI event, patients with not-susceptible isolates had significantly more all-cause prescriptions orders (+ 1.41 [P = 0.001]), UTI-related prescriptions orders (+ 0.26 [P < 0.001]) and a higher probability of all-cause inpatient (+ 1.4% [P = 0.009]), outpatient (+ 6.1% [P = 0.006]), or UTI-related outpatient (+ 3.7% [P = 0.039]) encounters. Patients with a uUTI and an antibiotic-not-susceptible isolate were significantly more likely to progress to cUTI than those with susceptible isolates (odds ratio: 2.35 [confidence interval: 1.66–3.33; P < 0.001]). Over 6 months, patients with not-susceptible versus susceptible isolates had significantly higher all-cause costs (+ $426 [P = 0.031]) and UTI-related costs (+ $157 [P = 0.034]).

Conclusions

Patients with a uUTI caused by antibiotic-not-susceptible isolates had higher healthcare resource usage, costs, and increased likelihood of progressing to cUTI than those with antibiotic-susceptible isolates.

Antimicrobial resistance patterns of bacterial pathogens recovered from the urine of patients at Canadian hospitals from 2009 to 2020

Objectives

To investigate in vitro susceptibility patterns of bacterial pathogens recovered from the urine of outpatients (isolates from outpatient clinics or emergency departments) and hospital inpatients across Canada from 2009 to 2020 as part of the CANWARD study.

Methods

Canadian hospital microbiology laboratories submitted bacterial pathogens cultured from urine to the CANWARD study coordinating laboratory on an annual basis (January 2009 to December 2020). Antimicrobial susceptibility testing was performed by CLSI broth microdilution, with MICs interpreted by current CLSI breakpoints.

Results

In total, 4644 urinary pathogens were included in this study. Escherichia coli was recovered most frequently (53.3% of all isolates), followed by Enterococcus faecalis, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa and Staphylococcus aureus. Together, these six species accounted for 84.2% of study isolates. Nitrofurantoin demonstrated excellent in vitro activity versus E. coli, with 97.6% of outpatient and 96.1% of inpatient isolates remaining susceptible. In contrast, E. coli susceptibility rates were lower for ciprofloxacin (outpatient 79.5%, inpatient 65.9%) and trimethoprim/sulfamethoxazole (outpatient 75.2%, inpatient 73.5%). The percentage of E. coli isolates that were phenotypically positive for ESBL production significantly increased from 4.2% (2009-11) to 11.3% (2018-20). A similar although less pronounced temporal trend was observed with ESBL-producing K. pneumoniae.

Conclusions

E. coli was the pathogen most frequently recovered from the urine of Canadian patients, and the proportion of isolates that were ESBL producers increased over time. Susceptibility data presented here suggest that ciprofloxacin and trimethoprim/sulfamethoxazole may be suboptimal for the empirical treatment of complicated urinary infections.

Cefepime pharmacodynamic targets against Enterobacterales employing neutropenic murine lung infection and in vitro pharmacokinetic models

BACKGROUND

Very limited studies, so far, have been conducted to identify the pharmacodynamic targets of cefepime, a well-established fourth-generation cephalosporin. As a result, conventional targets representing the cephalosporin class are used for cefepime target attainment analysis.

OBJECTIVES

We employed both a neutropenic murine lung infection model and an in vitro pharmacokinetic model (IVPM) to determine cefepime's pharmacodynamic target [percentage of the dosing interval during which unbound drug concentrations remain higher than the MIC (%fT>MIC)] for bacteriostatic and 1 log10 kill effects.

METHODS

Ten strains with cefepime MICs ranging from 0.03 to 16 mg/L were studied in the lung infection. In the IVPM, five cefepime-resistant strains with cefepime/tazobactam (fixed 8 mg/L) MICs ranging from 0.25 to 8 mg/L were included. Through 24 h dose fractionation, both in lung infection and IVPM (in the latter case, tazobactam 8 mg/L continuous infusion was used to protect cefepime), varying cefepime exposures and corresponding pharmacodynamic effect scenarios were generated to identify the pharmacodynamic targets.

RESULTS

Using a non-linear sigmoidal maximum-effect (Emax) model, the cefepime's plasma fT>MIC for 1 log10 kill in lung infection ranged from 17% to 53.7% and a combined exposure-response plot yielded 30%. In the case of IVPM, T>MIC ranged from 6.9% to 75.4% with a mean value of 34.2% for 1 log10 kill.

CONCLUSIONS

Both in vivo and in vitro studies showed that cefepime's pharmacodynamic requirements are lower than generally reported for cephalosporins (50%-70% fT>MIC). The lower requirement for cefepime could be linked with factors such as cefepime's better permeation properties and multiple PBP affinity-driven enhanced bactericidal action.

Impact of suboptimal or inappropriate treatment on healthcare resource use and cost among patients with uncomplicated urinary tract infection: an analysis of integrated delivery network electronic health records

Background

Although uncomplicated urinary tract infections (uUTIs; occurring in female patients without urological abnormalities or history of urological procedures or complicating comorbidities) are one of the most common community infections in the United States (US), limited data are available concerning associations between antibiotic resistance, suboptimal prescribing, and the economic burden of uUTI. We examined the prevalence of suboptimal antibiotic prescribing and antibiotic resistance and its effects on healthcare resource use and costs.

Methods

This retrospective cohort study utilized electronic health record data from a large Mid-Atlantic US integrated delivery network database, collected July 2016–March 2020. Female patients aged ≥ 12 years with a uUTI, who received ≥ 1 oral antibiotic treatment within ± 5 days of index uUTI diagnosis, and had ≥ 1 urine culture with antimicrobial susceptibility test, were eligible for inclusion in the study. The study examined the proportion of antibiotics that were inappropriately or suboptimally prescribed among patients with confirmed uUTI, and total healthcare costs (all-cause and UTI-related) within 6 months after a uUTI, stratified by antibiotic susceptibility and/or inappropriate or suboptimal treatment. Patient outcomes were assessed after 1:1 propensity score matching of patients with antibiotic-susceptible versus not-susceptible isolates and then by other covariates (e.g., demographics and recent healthcare use). A similar propensity score calculation was used to analyze the effect of inappropriate/suboptimal treatment on health outcomes. Costs were adjusted to 2020 US dollars ($).

Results

Among 2565 patients with a uUTI included in the analysis, the most commonly prescribed antibiotics were nitrofurantoin (61%), trimethoprim-sulfamethoxazole (19%), and ciprofloxacin (15%). More than one-third of the sample (40.2%) had isolates that were not-susceptible to ≥ 1 antibiotic indicated for treating patients with uUTI. Two-thirds (66.6%) of study-eligible patients were prescribed appropriate treatment; 29.9% and 11.9% were prescribed suboptimal and/or inappropriate treatment, respectively. Inappropriate or suboptimally prescribed patients had greater all-cause and UTI-related costs compared with appropriately prescribed patients. Differences were most striking among patients with antibiotic not-susceptible isolates.

Conclusions

These findings highlight how the increasing prevalence of antibiotic resistance combined with suboptimal treatment of patients with uUTI increases the burden on healthcare systems. The finding underlines the need for improved prescribing accuracy by better understanding regional resistance rates and developing improved diagnostic tests.

Hospital-onset bacteremia and fungemia: An evaluation of predictors and feasibility of benchmarking comparing two risk-adjusted models among 267 hospitals

Objectives:

To evaluate the prevalence of hospital-onset bacteremia and fungemia (HOB), identify hospital-level predictors, and to evaluate the feasibility of an HOB metric.

Methods:

We analyzed 9,202,650 admissions from 267 hospitals during 2015–2020. An HOB event was defined as the first positive blood-culture pathogen on day 3 of admission or later. We used the generalized linear model method via negative binomial regression to identify variables and risk markers for HOB. Standardized infection ratios (SIRs) were calculated based on 2 risk-adjusted models: a simple model using descriptive variables and a complex model using descriptive variables plus additional measures of blood-culture testing practices. Performance of each model was compared against the unadjusted rate of HOB.

Results:

Overall median rate of HOB per 100 admissions was 0.124 (interquartile range, 0.00–0.22). Facility-level predictors included bed size, sex, ICU admissions, community-onset (CO) blood culture testing intensity, and hospital-onset (HO) testing intensity, and prevalence (all P < .001). In the complex model, CO bacteremia prevalence, HO testing intensity, and HO testing prevalence were the predictors most associated with HOB. The complex model demonstrated better model performance; 55% of hospitals that ranked in the highest quartile based on their raw rate shifted to a lower quartile when the SIR from the complex model was applied.

Conclusions:

Hospital descriptors, aggregate patient characteristics, community bacteremia and/or fungemia burden, and clinical blood-culture testing practices influence rates of HOB. Benchmarking an HOB metric is feasible and should endeavor to include both facility and clinical variables.

Research needs for optimising wastewater-based epidemiology monitoring for public health protection

Wastewater-based epidemiology (WBE) is an unobtrusive method used to observe patterns in illicit drug use, poliovirus, and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The pandemic and need for surveillance measures have led to the rapid acceleration of WBE research and development globally. With the infrastructure available to monitor SARS-CoV-2 from wastewater in 58 countries globally, there is potential to expand targets and applications for public health protection, such as other viral pathogens, antimicrobial resistance (AMR), pharmaceutical consumption, or exposure to chemical pollutants. Some applications have been explored in academic research but are not used to inform public health decision-making. We reflect on the current knowledge of WBE for these applications and identify barriers and opportunities for expanding beyond SARS-CoV-2. This paper critically reviews the applications of WBE for public health and identifies the important research gaps for WBE to be a useful tool in public health. It considers possible uses for pathogenic viruses, AMR, and chemicals. It summarises the current evidence on the following: (1) the presence of markers in stool and urine; (2) environmental factors influencing persistence of markers in wastewater; (3) methods for sample collection and storage; (4) prospective methods for detection and quantification; (5) reducing uncertainties; and (6) further considerations for public health use.