Third-Generation Cephalosporin Resistance and Associated Discordant Antibiotic Treatment in Emergency Department Febrile Urinary Tract Infections

Lack of wastewater treatment in a small town drives the spread of ESBL-producing Escherichia coli in irrigation waters

Antibiotic resistance (ABR) is a critical and growing global challenge, especially in low- and middle-income countries. Ecuador has made great progress in connecting households to piped water supplies; however, the collection and treatment of domestic wastewater has lagged. This infrastructural gap may be accelerating the spread of ABR into surface waters used downstream for irrigation. We studied the contributions of a small town in Ecuador to the prevalence of extended-spectrum β-lactamase-producing Escherichia coli in a glacial stream used for irrigating crops. The study analyzed water samples upstream (n = 60) and downstream (n = 60) of the town of Píntag as well as 30 lettuce samples irrigated by surface waters downstream of the town. A subset of third generation cephalosporin resistant E. coli (3GCR-EC) isolates (n = 58) were sequenced to characterize antibiotic resistance genes and pathogenic lineages. Our results showed that there was nearly a three-log increase in mean E. coli colony forming units in the downstream samples versus upstream. At the upstream sites above the town of Píntag, 6.7% of water samples were positive for 3GCR-EC compared to 100% of samples collected at the downstream sites. Additionally, 70.1% of sequenced 3GCR-EC isolates collected at downstream sites carried blaCTX-M genes and 3.4% belonged to pandemic lineages ST131 and ST10. As countries develop household piped water infrastructure, attention should focus on how the lack of domestic wastewater collection and treatment may accelerate the spread of ABR in waterways and the food system.

Economic Burden of Community-Acquired Antibiotic-Resistant Urinary Tract Infections: Systematic Review and Meta-Analysis

Background

Antibiotic resistance (ABR) poses a major burden to global health and economic systems. ABR in community-acquired urinary tract infections (CA-UTIs) has become increasingly prevalent. Accurate estimates of ABR's clinical and economic burden are needed to support medical resource prioritization and cost-effectiveness evaluations of urinary tract infection (UTI) interventions.

Objective

This study aims to systematically synthesize the evidence on the economic costs associated with ABR in CA-UTIs, using published studies comparing the costs of antibiotic-susceptible and antibiotic-resistant cases.

Methods

We searched the PubMed, Ovid MEDLINE and Embase, Cochrane Review Library, and Scopus databases. Studies published in English from January 1, 2008, to January 31, 2023, reporting the economic costs of ABR in CA-UTI of any microbe were included. Independent screening of titles/abstracts and full texts was performed based on prespecified criteria. A quality assessment was performed using the Integrated Quality Criteria for Review of Multiple Study Designs (ICROMS) tool. Data in UTI diagnosis criteria, patient characteristics, perspectives, resource costs, and patient and health economic outcomes, including mortality, hospital length of stay (LOS), and costs, were extracted and analyzed. Monetary costs were converted into 2023 US dollars.

Results

This review included 15 studies with a total of 57,251 CA-UTI cases. All studies were from high- or upper-middle-income countries. A total of 14 (93%) studies took a health system perspective, 13 (87%) focused on hospitalized patients, and 14 (93%) reported UTI pathogens. Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa are the most prevalent organisms. A total of 12 (80%) studies reported mortality, of which, 7 reported increased mortality in the ABR group. Random effects meta-analyses estimated an odds ratio of 1.50 (95% CI 1.29-1.74) in the ABR CA-UTI cases. All 13 hospital-based studies reported LOS, of which, 11 reported significantly higher LOS in the ABR group. The meta-analysis of the reported median LOS estimated a pooled excess LOS ranging from 1.50 days (95% CI 0.71-4.00) to 2.00 days (95% CI 0.85-3.15). The meta-analysis of the reported mean LOS estimated a pooled excess LOS of 2.45 days (95% CI 0.51-4.39). A total of 8 (53%) studies reported costs in monetary terms-none discounted the costs. All 8 studies reported higher medical costs spent treating patients with ABR CA-UTI in hospitals. The highest excess cost was observed in UTIs caused by carbapenem-resistant Enterobacterales. No meta-analysis was performed for monetary costs due to heterogeneity.

Conclusions

ABR was attributed to increased mortality, hospital LOS, and economic costs among patients with CA-UTI. The findings of this review highlighted the scarcity of research in this area, particularly in patient morbidity and chronic sequelae and costs incurred in community health care. Future research calls for a cost-of-illness analysis of infections, standardizing therapy-pathogen combination comparators, medical resources, productivity loss, intangible costs to be captured, and data from community sectors and low-resource settings and countries.

Is It Safe to Treat Stable Patients with Bacteremic Urinary Tract Infections with High-Resistant-Rate Antibiotics?

BACKGROUND AND OBJECTIVES

In most areas of the world, urine bacteria have high resistance rates to third-generation cephalosporins, and it is unclear if it is safe to treat stable patients with bacteremic urinary tract infections (UTI) with those antibiotics. There are recommendations that empiric therapy for a suspected UTI should include only antibiotics with resistance rates less than 10%.

MATERIALS AND METHODS

In this historical observational single center study, we selected 180 stable internal medicine patients hospitalized between January 2019 and December 2021, with identical bacteria isolated from blood and urine cultures. Charts were reviewed to determine if deaths and readmissions up to 30 days after discharge were due to bacterial resistance to initial antibiotic therapy (BRIAT).

RESULTS

The patient's median age was 82 years (1st-3rd quartiles, 73-87 years). A total of 54.4% were female. There were 125 patients treated with ceftriaxone. A total of 38 (30.3%) had BRIAT. Four patients died, but none were because of a delay in appropriate treatment. The median days of hospitalization for all patients was 7 days, and 9 days versus 6 days in those with and without BRIAT. There were no re-hospitalizations for a UTI in patients with BRIAT.

CONCLUSIONS

We conclude that, despite high resistance rates, empiric ceftriaxone in stable hospitalized patients with a bacteremic UTI is safe. There was no urosepsis-related mortality during the hospitalization or on follow-up. The treatment of all patients with wider-spectrum antibiotics might have decreased the median hospital stay by only one day. The potential effect would be even lower if all patients with a suspected systemic UTI were treated with wide-spectrum antibiotics, because some patients do not have an infection of the urinary tract. A reassessment of the recommendation that empiric therapy for a suspected systemic urinary tract infection should include only wider-spectrum antibiotics is warranted.

Laboratory Tests, Bacterial Resistance, and Treatment Options in Adult Patients Hospitalized with a Suspected Urinary Tract Infection

Patients treated for systemic urinary tract infections commonly have nonspecific presentations, and the specificity of the results of the urinalysis and urine cultures is low. In the following narrative review, we will describe the widespread misuse of urine testing, and consider how to limit testing, the disutility of urine cultures, and the use of antibiotics in hospitalized adult patients. Automated dipstick testing is more precise and sensitive than the microscopic urinalysis which will result in false negative test results if ordered to confirm a positive dipstick test result. There is evidence that canceling urine cultures if the dipstick is negative (negative leukocyte esterase, and nitrite) is safe and helps prevent the overuse of urine cultures. Because of the side effects of introducing a urine catheter, for patients who cannot provide a urine sample, empiric antibiotic treatment should be considered as an alternative to culturing the urine if a trial of withholding antibiotic therapy is not an option. Treatment options that will decrease both narrower and wider spectrum antibiotic use include a period of watching and waiting before antibiotic therapy and empiric treatment with antibiotics that have resistance rates > 10%. Further studies are warranted to show the option that maximizes patient comfort and safety.

The Diagnosis and Treatment of Adult Urinary Tract Infections in the Emergency Department

Emergency medicine has been called the art of "making complicated clinical decisions with limited information." This description is particularly relevant in the case of diagnosis and treatment of urinary tract infections (UTIs). Although common, UTIs are often challenging to diagnose given the presence of non-specific signs and symptoms and over-reliance on laboratory findings. This review provides an interdisciplinary interpretation of the primary literature and practice guidelines, with a focus on diagnostic and antimicrobial stewardship in the emergency department.

A growing battlefield in the war against biofilm-induced antimicrobial resistance: insights from reviews on antibiotic resistance

Biofilms are a common survival strategy employed by bacteria in healthcare settings, which enhances their resistance to antimicrobial and biocidal agents making infections difficult to treat. Mechanisms of biofilm-induced antimicrobial resistance involve reduced penetration of antimicrobial agents, increased expression of efflux pumps, altered microbial physiology, and genetic changes in the bacterial population. Factors contributing to the formation of biofilms include nutrient availability, temperature, pH, surface properties, and microbial interactions. Biofilm-associated infections can have serious consequences for patient outcomes, and standard antimicrobial therapies are often ineffective against biofilm-associated bacteria, making diagnosis and treatment challenging. Novel strategies, including antibiotics combination therapies (such as daptomycin and vancomycin, colistin and azithromycin), biofilm-targeted agents (such as small molecules (LP3134, LP3145, LP4010, LP1062) target c-di-GMP), and immunomodulatory therapies (such as the anti-PcrV IgY antibodies which target Type IIIsecretion system), are being developed to combat biofilm-induced antimicrobial resistance. A multifaceted approach to diagnosis, treatment, and prevention is necessary to address this emerging problem in healthcare settings.

The Interventions and Challenges of Antimicrobial Stewardship in the Emergency Department

Over the last decades, we have witnessed a constant increase in infections caused by multi-drug-resistant strains in emergency departments. Despite the demonstrated effectiveness of antimicrobial stewardship programs in antibiotic consumption and minimizing multi-drug-resistant bacterium development, the characteristics of emergency departments pose a challenge to their implementation. The inclusion of rapid diagnostic tests, tracking microbiological results upon discharge, conducting audits with feedback, and implementing multimodal educational interventions have proven to be effective tools for optimizing antibiotic use in these units. Nevertheless, future multicenter studies are essential to determine the best way to proceed and measure outcomes in this scenario.

Antimicrobial Peptides Demonstrate Activity against Resistant Bacterial Pathogens

The antimicrobial resistance crisis is an ongoing major threat to public health safety. Low- and middle-income countries are particularly susceptible to higher fatality rates and the economic impact of antimicrobial resistance (AMR). As an increasing number of pathogens emerge with multi- and pan-drug resistance to last-resort antibiotics, there is an urgent need to provide alternative antibacterial options to mitigate disease transmission, morbidity, and mortality. As identified by the World Health Organization (WHO), critically important pathogens such as Klebsiella and Pseudomonas species are becoming resistant to last-resort antibiotics including colistin while being frequently isolated from clinical cases of infection. Antimicrobial peptides are potent amino acid sequences produced by many life forms from prokaryotic, fungal, plant, to animal species. These peptides have many advantages, including their multi-hit mode of action, potency, and rapid onset of action with low levels of resistance being evident. These innate defense mechanisms also have an immune-stimulating action among other activities in vivo, thus making them ideal therapeutic options. Large-scale production and formulation issues (pharmacokinetics, pharmacodynamics), high cost, and protease instability hinder their mass production and limit their clinical application. This review outlines the potential of these peptides to act as therapeutic agents in the treatment of multidrug-resistant infections considering the mode of action, resistance, and formulation aspects. Clinically relevant Gram-positive and Gram-negative pathogens are highlighted according to the WHO priority pathogen list.

Increase in the Rate of Gut Carriage of Fluoroquinolone-Resistant Escherichia coli despite a Reduction in Antibiotic Prescriptions

Background : Fluoroquinolone use for urinary tract infections has been steadily declining. Gut microbiota is the main reservoir for uropathogenic Escherichia coli but whether the carriage of fluoroquinolone-resistant E. coli has been changing is unknown. Methods . We determined the frequency of isolation and other characteristics of E. coli nonsuceptible to fluoroquinolones (at ³0.5 mg/L of ciprofloxacin) in 515 and 1605 E. coli -positive fecal samples collected in 2015 and 2021, respectively, from non-antibiotic- taking women of age 50+ receiving care in the Seattle area Kaiser Permanente Washington healthcare system. Results . Between 2015 and 2021 the prescription of fluoroquinolones dropped nearly three-fold in the study population. During the same period, the rates of gut carriage of fluoroquinolone-resistant E. coli increased from 14.4 % to 19.9% (P=.005), driven by a significant increase of isolates from the recently emerged, pandemic multi-drug resistant clonal group ST1193 (1.7% to 4.3%; P=.007) and those with an incomplete set of or no fluoroquinolone-resistance determining mutations (2.3% to 7.5%; P<.001). While prevalence of the resistance-associated mobile genes among the isolates dropped from 64.1% to 32.6% (P<.001), co-resistance to third generation cephalosporins has increased 21.5% to 33.1%, P=.044). Conclusion . Despite reduction in fluoroquinolone prescriptions, gut carriage of fluoroquinolone-resistant uropathogenic E. coli increased with a rise of previously sporadic lineages and co-resistance to third generation cephalosporins. Thus, to reduce the rates of antibiotic resistant urinary tract infections, greater focus should be on controlling the gut carriage of resistant bacteria.

Genetic Predictive Factors for Nonsusceptible Phenotypes and Multidrug Resistance in Expanded-Spectrum Cephalosporin-Resistant Uropathogenic Escherichia coli from a Multicenter Cohort: Insights into the Phenotypic and Genetic Basis of Coresistance

Antimicrobial resistance in urinary tract infections (UTIs) is a major public health concern. This study aims to characterize the phenotypic and genetic basis of multidrug resistance (MDR) among expanded-spectrum cephalosporin-resistant (ESCR) uropathogenic Escherichia coli (UPEC) causing UTIs in California patient populations. Between February and October 2019, 577 ESCR UPEC isolates were collected from patients at 6 clinical laboratory sites across California. Lineage and antibiotic resistance genes were determined by analysis of whole-genome sequence data. The lineages ST131, ST1193, ST648, and ST69 were predominant, representing 46%, 5.5%, 4.5%, and 4.5% of the collection, respectively. Overall, 527 (91%) isolates had an expanded-spectrum β-lactamase (ESBL) phenotype, with bla_CTX-M-15, bla_CTX-M-27, bla_CTX-M-55, and bla_CTX-M-14 being the most prevalent ESBL genes. In the 50 non-ESBL phenotype isolates, 40 (62%) contained bla_CMY-2, which was the predominant plasmid-mediated AmpC (pAmpC) gene. Narrow-spectrum β-lactamases, bla_TEM-1B and bla_OXA-1, were also found in 44.9% and 32.1% of isolates, respectively. Among ESCR UPEC isolates, isolates with an ESBL phenotype had a 1.7-times-greater likelihood of being MDR than non-ESBL phenotype isolates (P < 0.001). The cooccurrence of bla_CTX-M-15, bla_OXA-1, and aac(6')-Ib-cr within ESCR UPEC isolates was strongly correlated. Cooccurrence of bla_CTX-M-15, bla_OXA-1, and aac(6')-Ib-cr was associated with an increased risk of nonsusceptibility to piperacillin-tazobactam, cefepime, fluoroquinolones, and amikacin as well as MDR. Multivariate regression revealed the presence of bla_CTX-M-55, bla_TEM-1B, and the ST131 genotype as predictors of MDR. IMPORTANCE The rising incidence of resistance to expanded-spectrum cephalosporins among Escherichia coli strains, the most common cause of UTIs, is threatening our ability to successfully empirically treat these infections. ESCR E. coli strains are often MDR; therefore, UTI caused by these organisms often leads to treatment failure, increased length of hospital stay, and severe complications (D. G. Mark, Y.-Y. Hung, Z. Salim, N. J. Tarlton, et al., Ann Emerg Med 78:357-369, 2021, https://doi.org/10.1016/j.annemergmed.2021.01.003). Here, we performed an in-depth analysis of genetic factors of ESCR E. coli associated with coresistance and MDR. Such knowledge is critical to advance UTI diagnosis, treatment, and antibiotic stewardship.

Predictive Value of a Quick Pitt Bacteremia Score for Prognosis of Patients with Bloodstream Infection Secondary to Urinary Tract Infection: A Retrospective Cohort Study

Purpose

To analyze the effect of a quick Pitt bacteremia score (qpitt) on the prognosis of patients with bloodstream infection (BSI) secondary to urinary tract infection (UTI) and to further explore its use in aiding appropriate selection of initial antibiotic treatment.

Methods

Medical records of patients with BSIs secondary to UTIs who were admitted to our hospital from January 2018 to December 2020 were retrospectively collected. To screen for independent risk factors, logistic analysis was conducted on statistically significant variables. The receiver operating characteristic (ROC) curve was drawn with prognosis and death as the state variables to evaluate the predictive value. Patients were grouped by qpitt 2-point cutoff, to explore the impact of initial antimicrobial treatment regimens on poor prognosis and death in different subgroups. Poor prognosis was defined as a hospital length of stay (HLOS) ≥14 days or death within 28 days from BSI onset (ie, 28-day death).

Results

A total of 266 patients were included in this study. In BSIs secondary to UTIs, we observed a pathogenic composition of 77.44% Gram-negative bacteria, 19.55% Gram-positive bacteria, and 3.01% fungi. The qpitt had poor predictive value for poor prognosis [area under ROC (AUROC) = 0.653, p < 0.001], while it had a high predictive value for death (AUROC = 0.890, p < 0.001). For patients with a qpitt ≥2, the poor prognosis and death rates of patients who were initially treated with carbapenem antibiotics were lower (p < 0.01). In comparison, initial treatment with carbapenem antibiotics had no significant effect on prognosis and death rates in patients with qpitt <2 (p > 0.1).

Conclusion

The qpitt is highly predictive for death in patients with BSIs secondary to UTIs and can be used to inform first-line antibiotic treatment strategy.

Short- and long-term mortality in patients with urosepsis caused by Escherichia coli susceptible and resistant to 3rd generation cephalosporins

Background

The aim of this study was to compare short- and long-term mortality among patients with urosepsis caused by Escherichia coli susceptibile (EC-SC) and resistant (EC-RC) to 3rd generation cephalosporins.

Methods

A retrospective cohort study that included all patients with E. coli urosepsis admitted to a 700-bed hospital from January 2014 until December 2019. Mortality up to 30 days, 6 months and 1 year was assessed using logistic multivariate regression analysis and Cox regression analysis.

Results

A total of 313 adult were included, 195 with EC-SC and 118 patients with EC-RC. 205 were females (74%), mean age was 79 (SD 12) years. Mean Charlson score was 4.93 (SD 2.18) in the EC-SC group and 5.74 (SD 1.92) in the EC-RC group. Appropriate empiric antibiotic therapy was initiated in 245 (78.3%) patients, 100% in the EC-SC group but only 42.5% in the EC-RC group. 30-day mortality occurred in 12 (6.3%) of EC-SC group and 15 (12.7%) in the EC-RC group. Factors independently associated with 30-day mortality were Charlson score, Pitt bacteremia score, fever upon admission and infection with a EC-RC. Appropriate antibiotic therapy was not independently associated with 30-day mortality. Differences in mortality between groups remained significant one year after the infection and were significantly associated with the Charlson co-morbidity score.

Conclusions

Mortality in patients with urosepsis due to E. coli is highly affected by age and comorbidities. Although mortality was higher in the EC-RC group, we could not demonstrate an association with inappropriate empirical antibiotic treatment. Mortality remained higher at 6 months and 1 year long after the infection resolved but was associated mainly with co-morbidity.

A multicenter analysis of trends in resistance in urinary Enterobacterales isolates from ambulatory patients in the United States: 2011-2020

BACKGROUND

Urinary tract infections (UTIs), which are usually caused by bacteria in the Enterobacterales family, are a common reason for outpatient visits. Appropriate empiric therapy for UTIs requires an understanding of antibiotic resistance in the community. In this nationwide study, we examined trends in antibiotic resistance in urinary Enterobacterales isolates from ambulatory patients in the United States (US).

METHODS

We analyzed the antimicrobial susceptibility profiles (extended-spectrum beta-lactamase [ESBL]-producing phenotype and not susceptible [NS] to beta-lactams, trimethoprim/sulfamethoxazole [TMP/SMX], fluoroquinolones [FQ], or nitrofurantoin [NFT]) of 30-day non-duplicate Enterobacterales isolates from urine cultures tested at ambulatory centers in the BD Insights Research Database (2011-2020). The outcome of interest was the percentage of resistant isolates by pathogen and year. Multi-variable generalized estimating equation models were used to assess trends in resistance over time and by additional covariates.

RESULTS

A total of 338 US facilities provided data for > 2.2 million urinary Enterobacterales isolates during the 10-year study. Almost three-quarters (72.8%) of Enterobacterales isolates were Escherichia coli. Overall unadjusted resistance rates in Enterobacterales isolates were 57.5%, 23.1%, 20.6%, and 20.2% for beta-lactams, TMP/SMX, FQ, and NFT, respectively, and 6.9% had an ESBL-producing phenotype. Resistance to two or more antibiotic classes occurred in 16.4% of isolates and 5.5% were resistant to three or more classes. Among isolates with an ESBL-producing phenotype, 70.1%, 59.9%, and 33.5% were NS to FQ, TMP/SMX, and NFT, respectively. In multivariable models, ESBL-producing and NFT NS Enterobacterales isolates increased significantly (both P < 0.001), while other categories of resistance decreased. High rates (≥ 50%) of beta-lactam and NFT resistance were observed in Klebsiella isolates and in non-E. coli, non-Klebsiella Enterobacterales isolates.

CONCLUSIONS

Antimicrobial resistance was common in urinary Enterobacterales isolates. Isolates with an ESBL-producing phenotype increased by about 30% between 2011 and 2020, and significant increases were also observed in NFT NS Enterobacterales isolates. Resistance rates for all four antibiotic classes were higher than thresholds recommended for use as empiric therapy. Non-E. coli Enterobacterales isolates showed high levels of resistance to commonly used empiric antibiotics, including NFT. These data may help inform empiric therapy choices for outpatients with UTIs.

Clinical Outcome of Discordant Empirical Therapy and Risk Factors Associated to Treatment Failure in Children Hospitalized for Urinary Tract Infections

With the spread of antibiotic resistance in pediatric urinary tract infections (UTIs), more patients are likely to be started empirically on antibiotics to which pathogens are later found to be resistant (discordant therapy). However, in-vivo effectiveness may be different from in-vitro susceptibility. Aims of this study were to describe clinical outcomes of discordant empirical treatments in pediatric UTIs and to investigate risk factors associated to treatment failure. This observational, retrospective study was conducted on children hospitalized for febrile UTIs with positive urine culture and started on discordant empirical therapy. Failure rates of discordant treatments and associated risk factors were investigated. A total of 142/1600 (8.9%) patients were treated with inadequate empirical antibiotics. Clinical failure was observed in 67/142 (47.2%) patients, with no fatal events. Higher failure rates were observed for combinations of penicillin and beta-lactamase inhibitors (57.1%). Significant risk factors for failure of discordant treatment were history of recurrent UTIs (95% CI: 1.13–9.98, OR: 3.23, p < 0.05), recent use of antibiotics (95% CI: 1.46–21.82, OR: 5.02, p < 0.01), infections caused by Pseudomonas aeruginosa (95% CI: 1.85–62.10, OR: 7.30, p < 0.05), and empirical treatment with combinations of penicillin and beta-lactamase inhibitors (95% CI: 0.94–4.03, OR: 1.94, p = 0.05). This study showed that discordant empirical treatments may still be effective in more than half of pediatric UTIs. Clinical effectiveness varies between different discordant antibiotics in pediatric UTIs, and patients presenting risk factors for treatment failure may need a differentiated empirical approach.

Rise in the prevalence of resistance to extended-spectrum cephalosporins in the USA, nursing homes and antibiotic prescribing in outpatient and inpatient settings

The prevalence of resistance to extended-spectrum (ES) cephalosporins for multiple types of infections treated in US hospitals and the incidence of hospitalization with ESBL-producing Enterobacteriaceae (many of which are detected in nursing home residents) have grown markedly in recent years. Here, I review these developments, as well as evidence for their adverse consequences, including the increase in the overall burden of bacterial infections due to proliferation of ESBL-producing/ES cephalosporin-resistant bacteria, the contribution of ESBL-producing/ES cephalosporin-resistant bacteria to the increase in the burden of mortality associated with bacterial infections and the contribution of the proliferation of ESBL-producing bacteria to the prevalence of carbapenem resistance. I argue that in order to mitigate the escalation of these phenomena, a reduction in outpatient prescribing of cephalosporins, especially to older adults, mitigation of transmission of ESBL-producing organisms in nursing homes and a reduction in inpatient prescribing of ES cephalosporins (which has seen a major increase in recent years) are needed.