Epidemiology, Clinical Features, and Antimicrobial Resistance of Invasive Escherichia Coli Disease in Patients Admitted in Tertiary Care Hospitals

Economic and Disease Burden Associated with Invasive Escherichia coli Disease in the United States

INTRODUCTION

Invasive Escherichia coli disease (IED) incidence has increased over recent years among aging populations and has rising antimicrobial resistance. Here, we report on a comparative, cross-sectional, retrospective analysis of US patients with IED to quantify IED-related healthcare resource utilization (HCRU), costs, and impact on health-related quality of life (HRQoL).

METHODS

This study included Kaiser Permanente Northwest (KPNW) members aged ≥ 60 years enrolled between July 2019 and January 2020. Patients were divided into three groups: Group 1 had experienced a recent IED episode (≤ 3 weeks before enrollment); Group 2 had experienced a former IED episode (13-18 months before enrollment); Group 3 was at risk with no prior history of IED. Data were collected from electronic hospital records, a patient survey, and the EuroQol 5-Dimension 5-Level (EQ-5D-5L) questionnaire. Mean costs were adjusted according to individual follow-up.

RESULTS

Patient characteristics were generally consistent across Groups 1 (n = 289), 2 (n = 319), and 3 (n = 340). Inpatient hospitalization was observed in 84%, 44%, and 15% of patients in Groups 1, 2 and 3, respectively. Mean direct costs per patient (per 30-day follow-up) were $17,168, $2530, and $1094 in Groups 1, 2, and 3, respectively. Mean total costs per patient in the year following an IED episode (Group 2) were $35,034 vs. $16,163 in the at-risk Group 3. HRQoL was poor for patients with recent IED, with a mean EQ-5D-5L utility index value of 0.25 on the worst day of illness. During a 12-month follow-up period, rehospitalization rates and mean number of antibiotic prescriptions were ~ threefold higher for patients who recovered from IED vs. those at risk.

CONCLUSIONS

These data demonstrate substantial short- and long-term impacts of IED on HCRU, IED-related costs, and HRQoL. Additional research is needed to further value the impact of novel IED prevention strategies.

Risk of Invasive Escherichia coli (E. coli) Disease After Elective Urologic Procedures Among Older Adults in the United States

INTRODUCTION

Little is known about the risk of invasive E. coli disease (IED) after elective urologic procedures. We estimated the risk of IED after selected urologic procedures in patients with or without antibiotic prophylaxis, and in controls with no urologic or other surgical procedures.

METHODS

The Komodo Research Database (01/01/2021-06/30/2023) was used to identify patients ≥ 60 years old with selected urological procedures (index: first urologic procedure date) and randomly selected controls without surgical procedures (index: random date). Patients with urologic procedures were classified into two cohorts based on whether or not they received antibiotic prophylaxis within 14 days prior to and on index date. Entropy balancing adjusted for differences between groups in selected patient characteristics over 6 months pre-index (baseline). IED rates within 30 days post-index were assessed based on recorded diagnosis of E. coli sepsis (ICD-10-CM: A41.51); odds ratios (OR) were estimated using weighted logistic regression. Sensitivity analyses within 90 days and using broader claims-based algorithm for IED were performed.

RESULTS

Overall, 141,418 patients had urologic procedures with antibiotic prophylaxis, 200,062 had them without antibiotic prophylaxis, and 424,254 had no procedures. Within 30 days post-index, IED rates were 0.48% and 0.72% among patients with or without antibiotic prophylaxis, respectively, vs. 0.02% among those without any procedures. Among patients with urologic procedures,  > 70% of IED events occurred within 30 days. Patients who had urologic procedures without prophylaxis had a higher risk of developing IED than those with prophylaxis (OR = 1.50, 95% confidence interval [CI: 1.37-1.65]), while patients without any procedures had a lower risk than those with urologic procedures and prophylaxis (OR = 0.04, 95% CI [0.03-0.05]). Similar results were obtained in sensitivity analyses.

CONCLUSIONS

Urologic procedures were associated with an increased IED risk even with antibiotic prophylaxis. Results suggest an unmet need for additional preventative measures to reduce the burden of IED after urologic procedures.

Lineage-specific variation in frequency and hotspots of recombination in invasive Escherichia coli

BACKGROUND

The opportunistic bacterium Escherichia coli can invade normally sterile sites in the human body, potentially leading to life-threatening organ dysfunction and even death. However, our understanding of the evolutionary processes that shape its genetic diversity in this sterile environment remains limited. Here, we aim to quantify the frequency and characteristics of homologous recombination in E. coli from bloodstream infections.

RESULTS

Analysis of 557 short-read genome sequences revealed that the propensity to exchange DNA by homologous recombination varies within a distinct population (bloodstream) at narrow geographic (Dartmouth Hitchcock Medical Center, New Hampshire, USA) and temporal (years 2016 - 2022) scope. We identified the four largest monophyletic sequence clusters in the core genome phylogeny that are represented by prominent sequence types (ST): BAPS1 (mainly ST95), BAPS4 (mainly ST73), BAPS10 (mainly ST131), BAPS14 (mainly ST58). We show that the four dominant clusters vary in different characteristics of recombination: number of single nucleotide polymorphisms due to recombination, number of recombination blocks, cumulative bases in recombination blocks, ratio of probabilities that a given site was altered through recombination and mutation (r/m), and ratio of rates at which recombination and mutation occurred (ρ/θ). Each sequence cluster contains a unique set of antimicrobial resistance (AMR) and virulence genes that have experienced recombination. Common among the four sequence clusters were the recombined virulence genes with functions associated with the Curli secretion channel (csgG) and ferric enterobactin transport (entEF, fepEG). We did not identify any one recombined AMR gene that was present in all four sequence clusters. However, AMR genes mdtABC, baeSR, emrKY and tolC had experienced recombination in sequence clusters BAPS4, BAPS10, and BAPS14. These differences lie in part on the contributions of vertically inherited ancestral recombination and contemporary branch-specific recombination, with some genomes having relatively higher proportions of recombined DNA.

CONCLUSIONS

Our results highlight the variation in the propensity to exchange DNA via homologous recombination within a distinct population at narrow geographic and temporal ranges. Understanding the sources of the genetic variation in invasive E. coli will help inform the implementation of effective strategies to reduce the burden of disease and AMR.

E. Coli cytotoxic necrotizing factor-1 promotes colorectal carcinogenesis by causing oxidative stress, DNA damage and intestinal permeability alteration

BACKGROUND

Bacterial toxins are emerging as promising hallmarks of colorectal cancer (CRC) pathogenesis. In particular, Cytotoxic Necrotizing Factor 1 (CNF1) from E. coli deserves special consideration due to the significantly higher prevalence of this toxin gene in CRC patients with respect to healthy subjects, and to the numerous tumor-promoting effects that have been ascribed to the toxin in vitro. Despite this evidence, a definitive causal link between CNF1 and CRC was missing. Here we investigated whether CNF1 plays an active role in CRC onset by analyzing pro-carcinogenic key effects specifically induced by the toxin in vitro and in vivo.

METHODS

Viability assays, confocal microscopy of γH2AX and 53BP1 molecules and cytogenetic analysis were carried out to assess CNF1-induced genotoxicity on non-neoplastic intestinal epithelial cells. Caco-2 monolayers and 3D Caco-2 spheroids were used to evaluate permeability alterations specifically induced by CNF1, either in the presence or in the absence of inflammation. In vivo, an inflammatory bowel disease (IBD) model was exploited to evaluate the carcinogenic potential of CNF1. Immunohistochemistry and immunofluorescence stainings of formalin-fixed paraffin-embedded (FFPE) colon tissue were carried out as well as fecal microbiota composition analysis by 16 S rRNA gene sequencing.

RESULTS

CNF1 induces the release of reactive oxidizing species and chromosomal instability in non-neoplastic intestinal epithelial cells. In addition, CNF1 modifies intestinal permeability by directly altering tight junctions' distribution in 2D Caco-2 monolayers, and by hindering the differentiation of 3D Caco-2 spheroids with an irregular arrangement of these junctions. In vivo, repeated intrarectal administration of CNF1 induces the formation of dysplastic aberrant crypt foci (ACF), and produces the formation of colorectal adenomas in an IBD model. These effects are accompanied by the increased neutrophilic infiltration in colonic tissue, by a mixed pro-inflammatory and anti-inflammatory cytokine milieu, and by the pro-tumoral modulation of the fecal microbiota.

CONCLUSIONS

Taken together, our results support the hypothesis that the CNF1 toxin from E. coli plays an active role in colorectal carcinogenesis. Altogether, these findings not only add new knowledge to the contribution of bacterial toxins to CRC, but also pave the way to the implementation of current screening programs and preventive strategies.

Epidemiology of invasive Escherichia coli disease in adults in England, 2013-2017

Extraintestinal pathogenic Escherichia coli (ExPEC) causes invasive E. coli disease (IED), including bacteraemia and (uro)sepsis, resulting in a high disease burden, especially among older adults. This study describes the epidemiology of IED in England (2013-2017) by combining laboratory surveillance and clinical data. A total of 191 612 IED cases were identified. IED incidence increased annually by 4.4-8.2% across all ages and 2.8-7.6% among adults ≥60 years of age. When laboratory-confirmed urosepsis cases without a positive blood culture were included, IED incidence in 2017 reached 149.4/100 000 person-years among all adults and 368.4/100 000 person-years among adults ≥60 years of age. Laboratory-confirmed IED cases were identified through E. coli-positive blood samples (55.3%), other sterile site samples (26.3%), and urine samples (16.6%), with similar proportions observed among adults ≥60 years of age. IED-associated case fatality rates ranged between 11.8-13.2% among all adults and 13.1-14.7% among adults ≥60 years of age. This study reflects the findings of other published studies and demonstrates IED constitutes a major and growing global health concern disproportionately affecting the older adult population. The high case fatality rates observed despite available antibiotic treatments emphasize the growing urgency for effective intervention strategies. The burden of urosepsis due to E. coli is likely underestimated and requires additional investigation.

Review of Antimicrobial Properties of Titanium Dioxide Nanoparticles

There is a growing interest in the utilization of metal oxide nanoparticles as antimicrobial agents. This review will focus on titanium dioxide nanoparticles (TiO2 NPs), which have been demonstrated to exhibit high antimicrobial activity against bacteria and fungi, chemical stability, low toxicity to eukaryotic cells, and therefore high biocompatibility. Despite the extensive research conducted in this field, there is currently no consensus on how to enhance the antimicrobial efficacy of TiO2 NPs. The aim of this review is to evaluate the influence of various factors, including particle size, shape, composition, and synthesis parameters, as well as microbial type, on the antibacterial activity of TiO2 NPs against bacteria and fungi. Furthermore, the review offers a comprehensive overview of the methodologies employed in the synthesis and characterization of TiO2 NPs. The antimicrobial activity of TiO2 exhibits a weak dependence on the microorganism species. A tendency towards increased antibacterial activity is observed with decreasing TiO2 NP size. The dependence on the shape and composition is more pronounced. The most pronounced antimicrobial potential is exhibited by amorphous NPs and NPs doped with inorganic compounds. This review may be of interest to specialists in biology, medicine, chemistry, and other related fields.

A microbiological and genomic perspective of globally collected Escherichia coli from adults hospitalized with invasive E. coli disease

OBJECTIVES

Escherichia coli can cause infections in the urinary tract and in normally sterile body sites leading to invasive E. coli disease (IED), including bacteraemia and sepsis, with older populations at increased risk. We aimed to estimate the theoretical coverage rate by the ExPEC4V and 9V vaccine candidates. In addition, we aimed at better understanding the diversity of E. coli isolates, including their genetic and phenotypic antimicrobial resistance (AMR), sequence types (STs), O-serotypes and the bacterial population structure.

METHODS

Blood and urine culture E. coli isolates (n = 304) were collected from hospitalized patients ≥60 years (n = 238) with IED during a multicentric, observational study across three continents. All isolates were tested for antimicrobial susceptibility, O-serotyped, whole-genome sequenced and bioinformatically analysed.

RESULTS

A large diversity of STs and of O-serotypes were identified across all centres, with O25b-ST131, O6-ST73 and O1-ST95 being the most prevalent types. A total of 45.4% and 64.7% of all isolates were found to have an O-serotype covered by the ExPEC4V and ExPEC9V vaccine candidates, respectively. The overall frequency of MDR was 37.4% and ST131 was predominant among MDR isolates. Low in-patient genetic variability was observed in cases where multiple isolates were collected from the same patient.

CONCLUSIONS

Our results highlight the predominance of MDR O25b-ST131 E. coli isolates across diverse geographic areas. These findings provide further baseline data on the theoretical coverage of novel vaccines targeting E. coli associated with IED in older adults and their associated AMR levels.

A randomized phase 1/2a trial of ExPEC10V vaccine in adults with a history of UTI

The safety, reactogenicity, and immunogenicity of 3 doses of ExPEC10V (VAC52416), a vaccine candidate to prevent invasive Escherichia coli disease, were assessed in a phase 1/2a study (NCT03819049). In Cohort 1, ExPEC10V was well tolerated; the high dose was selected as optimal and further characterized in Cohort 2. Cohort 2 comprised a maximum 28-day screening, vaccination (Day 1), double-blind 181-day follow-up, and open-label long-term follow-up until Year 1. Healthy participants (≥60 years) with a history of urinary tract infection (UTI) within 5 years were randomized to receive ExPEC10V or placebo. The primary endpoint evaluated the safety and reactogenicity of ExPEC10V (solicited local and systemic AEs [until Day 15]; unsolicited AEs [until Day 30], SAEs [until Day 181], and immunogenicity [Day 30]) via multiplex electrochemiluminescent (ECL) and multiplex opsonophagocytic assay (MOPA). 416 participants (ExPEC10V, n = 278; placebo, n = 138) were included (mean age [SD], 68.8 [6.52] years; female, 79.6%; White, 96.1%). The incidence of solicited AEs was higher with ExPEC10V (local, 50.0% [n = 139]; systemic, 50.0% [n = 139]) than placebo (15.9% [n = 22]; 38.4% [n = 53]); rates of unsolicited AEs were comparable (ExPEC10V, 28.4% [n = 79]; placebo, 26.1% [n = 36]). No vaccine-related SAEs or deaths were reported. ExPEC10V elicited a robust antibody-mediated immunogenic response across all serotypes with ECL (Day 30 geometric mean fold increase, 2.33-8.18) and demonstrated functional opsonophagocytic killing activity across all measured serotypes (Day 30 geometric mean fold increase, 1.81-9.68). ExPEC10V exhibited an acceptable safety profile and a robust vaccine-induced functional immunogenic response in participants with a history of UTI. Clinical trial registration details: https://clinicaltrials.gov/study/NCT03819049 .

Expanding antibiotic, vaccine, and diagnostics development and access to tackle antimicrobial resistance

The increasing number of bacterial infections globally that do not respond to any available antibiotics indicates a need to invest in-and ensure access to-new antibiotics, vaccines, and diagnostics. The traditional model of drug development, which depends on substantial revenues to motivate investment, is no longer economically viable without push and pull incentives. Moreover, drugs developed through these mechanisms are unlikely to be affordable for all patients in need, particularly in low-income and middle-income countries. New, publicly funded models based on public-private partnerships could support investment in antibiotics and novel alternatives, and lower patients' out-of-pocket costs, making drugs more accessible. Cost reductions can be achieved with public goods, such as clinical trial networks and platform-based quality assurance, manufacturing, and product development support. Preserving antibiotic effectiveness relies on accurate and timely diagnosis; however scaling up diagnostics faces technological, economic, and behavioural challenges. New technologies appeared during the COVID-19 pandemic, but there is a need for a deeper understanding of market, physician, and consumer behaviour to improve the use of diagnostics in patient management. Ensuring sustainable access to antibiotics also requires infection prevention. Vaccines offer the potential to prevent infections from drug-resistant pathogens, but funding for vaccine development has been scarce in this context. The High-Level Meeting of the UN General Assembly in 2024 offers an opportunity to rethink how research and development can be reoriented to serve disease management, prevention, patient access, and antibiotic stewardship.

Clinical presentation and antimicrobial resistance of invasive Escherichia coli disease in hospitalized older adults: a prospective multinational observational study

BACKGROUND

Clinical data characterizing invasive Escherichia coli disease (IED) are limited. We assessed the clinical presentation of IED and antimicrobial resistance (AMR) patterns of causative E. coli isolates in older adults.

METHODS

EXPECT-2 (NCT04117113) was a prospective, observational, multinational, hospital-based study conducted in patients with IED aged ≥ 60 years. IED was determined by the microbiological confirmation of E. coli from blood; or by the microbiological confirmation of E. coli from urine or an otherwise sterile body site in the presence of requisite criteria of systemic inflammatory response syndrome (SIRS), Sequential Organ Failure Assessment (SOFA), or quick SOFA (qSOFA). The primary outcomes were the clinical presentation of IED and AMR rates of E. coli isolates to clinically relevant antibiotics. Complications and in-hospital mortality were assessed through 28 days following IED diagnosis.

RESULTS

Of 240 enrolled patients, 80.4% had bacteremic and 19.6% had non-bacteremic IED. One-half of infections (50.4%) were community-acquired. The most common source of infection was the urinary tract (62.9%). Of 240 patients, 65.8% fulfilled ≥ 2 SIRS criteria, and 60.4% had a total SOFA score of ≥ 2. Investigator-diagnosed sepsis and septic shock were reported in 72.1% and 10.0% of patients, respectively. The most common complication was kidney dysfunction (12.9%). The overall in-hospital mortality was 4.6%. Of 299 E. coli isolates tested, the resistance rates were: 30.4% for trimethoprim-sulfamethoxazole, 24.1% for ciprofloxacin, 22.1% for levofloxacin, 16.4% for ceftriaxone, 5.7% for cefepime, and 4.3% for ceftazidime.

CONCLUSIONS

The clinical profile of identified IED cases was characterized by high rates of sepsis. IED was associated with high rates of AMR to clinically relevant antibiotics. The identification of IED can be optimized by using a combination of clinical criteria (SIRS, SOFA, or qSOFA) and culture results.

Chromosomal and plasmid-encoded virulence and multidrug resistance of Escherichia coli ST58/24 infecting a 2-year-old sickle cell patient with sepsis in Kampala Uganda, East Africa

Sepsis and drug resistance represent a complex of the most common global causes of mortality in intensive care units (ICUs) especially among patients with comorbidities. Extraintestinal pathogenic Escherichia coli (ExPEC) strains are highly implicated in systemic infections, with multidrug resistance exacerbating the risk of chronic conditions and patient mortality. The diversity of virulence and evolution of multidrug resistance are yet to be fully deciphered. In this work, we aimed at unveiling the pathogens and their genomic determinants of virulence and drug resistance relevant to increased sepsis in a sickle cell child admitted to ICU. From a rectal swab, we isolated a strain of E. coli from the patient and phenotypically tested it against a panel of selected beta lactams, fluoroquinolones, macrolides, aminoglycosides and colistin. We then sequenced the entire genome and integrated multiple bioinformatic pipelines to divulge the virulence and multidrug resistance profiles of the isolate. Our results revealed that the isolate belongs to the sequence type (ST) 58/24, which (ST58), is a known ExPEC. With the use of PathogenFinder, we were able to confirm that this isolate is a human pathogen (p = 0.936). The assembled chromosome and two plasmids encode virulence factors related to capsule (antiphagocytosis), serum survival and resistance, type 6 secretion system (T6SS), multiple siderophores (iron acquisition), and biosynthetic gene clusters for polyketides and nonribosomal peptides exhibiting host cell damaging activity in silico. The genome also harbors multidrug resistance genotypes including extended spectrum beta lactamase (ESBL) genes such as blaTEM-1A/B, sulfonamide resistance genes sul1/2, fluoroquinolone resistance genes dfrA5 and nonsynonymous mutations of the gene pmrB, conferring intrinsic colistin resistance. Conclusively, this pathogen holds the potential to cause systemic infection and might exacerbate sickle cell anemia in the patient. The virulence and multidrug resistance profiles are encoded by both the chromosome and plasmids. Genomic surveillance of pathogens with multidrug resistance among patients with commodities is crucial for effective disease management.

Progress toward a vaccine for extraintestinal pathogenic E. coli (ExPEC) II: efficacy of a toxin-autotransporter dual antigen approach

Extraintestinal pathogenic Escherichia coli (ExPEC) is a leading cause of worldwide morbidity and mortality, the top cause of antimicrobial-resistant (AMR) infections, and the most frequent cause of life-threatening sepsis and urinary tract infections (UTI) in adults. The development of an effective and universal vaccine is complicated by this pathogen's pan-genome, its ability to mix and match virulence factors and AMR genes via horizontal gene transfer, an inability to decipher commensal from pathogens, and its intimate association and co-evolution with mammals. Using a pan virulome analysis of >20,000 sequenced E. coli strains, we identified the secreted cytolysin α-hemolysin (HlyA) as a high priority target for vaccine exploration studies. We demonstrate that a catalytically inactive pure form of HlyA, expressed in an autologous host using its own secretion system, is highly immunogenic in a murine host, protects against several forms of ExPEC infection (including lethal bacteremia), and significantly lowers bacterial burdens in multiple organ systems. Interestingly, the combination of a previously reported autotransporter (SinH) with HlyA was notably effective, inducing near complete protection against lethal challenge, including commonly used infection strains ST73 (CFT073) and ST95 (UTI89), as well as a mixture of 10 of the most highly virulent sequence types and strains from our clinical collection. Both HlyA and HlyA-SinH combinations also afforded some protection against UTI89 colonization in a murine UTI model. These findings suggest recombinant, inactive hemolysin and/or its combination with SinH warrant investigation in the development of an E. coli vaccine against invasive disease.

Impact of Invasive Escherichia Coli Disease on Clinical Outcomes and Medical Resource Utilization Among Asian Patients in the United States

INTRODUCTION

Invasive Escherichia coli disease (IED) can lead to sepsis and death and is associated with a substantial burden. Yet, there is scarce information on the burden of IED in Asian patients.

METHODS

This retrospective study used US hospital data from the PINC AI™ Healthcare database (October 2015-March 2020) to identify IED cases among patients aged ≥ 60 years. IED was defined as a positive E. coli culture in blood or other normally sterile body site (group 1 IED) or positive culture of E. coli in urine with signs of sepsis (group 2 IED). Eligible patients with IED were classified into Asian and non-Asian cohorts based on their reported race. Entropy balancing was used to create cohorts with similar characteristics. Outcomes following IED were descriptively reported in the balanced cohorts.

RESULTS

A total of 646 Asian and 19,127 non-Asian patients with IED were included (median age 79 years; 68% female after balancing). For both cohorts, most IED encounters had community-onset (> 95%) and required hospitalization (Asian 96%, mean duration 6.9 days; non-Asian 95%, mean duration 6.8 days), with frequent admission to intensive care (Asian 35%, mean duration 3.3 days; non-Asian 34%, mean duration 3.5 days), all standardized differences [SD] < 0.20. Compared to non-Asian patients, Asian patients were more likely to be discharged home (54% vs. 43%; SD = 0.22), and less likely to be discharged to a skilled nursing facility (24% vs. 31%; SD = 0.16). In-hospital fatality rates during the IED encounter were similar across cohorts (Asian 9%, non-Asian 10%; SD = 0.01). Most E. coli isolates showed resistance to ≥ 1 antibiotic (Asian 61%; non-Asian 64%) and 36% to ≥ 3 antibiotic classes (all SD < 0.20).

CONCLUSION

IED is associated with a substantial burden, including need for intensive care and considerable mortality, in Asian patients in the USA that is consistent with that observed for non-Asian patients.

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

BACKGROUND: Although invasive Escherichia coli disease (IED) can lead to severe clinical outcomes, little is known about the associated medical resource use and cost burden of IED in US hospitals. OBJECTIVE: To comprehensively describe medical resource use and costs associated with IED during the initial IED event and over the subsequent 12 months. METHODS: Patients aged 60 years or older with 1 or more IED encounters were identified from the PINC AI Healthcare US hospital database (October 1, 2015, to March 31, 2020). The index encounter was defined as the first encounter with a positive E coli culture in a normally sterile site (group 1 IED) or positive E coli culture in urine with signs of sepsis (group 2 IED). Encounters with a positive culture from other bacteria or fungal pathogens were excluded. Outcomes were descriptively reported between admission and discharge for the index encounter and more than 1 - year post-index discharge. Medical resource use and costs included inpatient admissions and outpatient hospital services; costs were reported from a hospital's perspective (ie, charged amount) in 2021 USD. RESULTS: A total of 19,773 patients were identified (group 1 IED = 51.8%; group 2 IED = 48.2%). Mean age was 76.8 years, 67.4% were female, and 82.1% were White. Most index encounters were community-onset (94.3%) and led to hospitalization (96.5%) (mean inpatient days = 6.9 days). During the 1 - year post-index, 36.8% of patients had 1 or more all-cause hospitalizations. Mean [median] total all-cause hospital costs (as captured through the PINC AI Healthcare database) amounted to $16,760 [$11,340] during the index encounter and $10,942 [$804] during the 1 - year post-index; these costs were higher in the presence of sepsis and multidrug resistance and among hospital-onset IED. CONCLUSIONS: IED is associated with a substantial medical resource use and economic burden both during the initial encounter and over the following year in older adults. This highlights the critical need and potential benefits of preventive measures that may reduce the incidence of IED and associated economic burden. DISCLOSURES: This study was funded by Janssen Global Services, LLC. Dr Hernandez-Pastor is an employee of Janssen Pharmaceutica NV. Dr Geurtsen is an employee of Janssen Vaccines & Prevention BV. Dr Baugh is an employee of Janssen Research & Development, LLC. Dr El Khoury is an employee of Janssen Global Services, LLC. Dr Kalu and Dr Krishnarajah are employees of Janssen Scientific Affairs, LLC. Dr Gauthier-Loiselle, Ms Bungay, and Mr Cloutier are employees of Analysis Group, Inc., a consulting company that provided paid consulting services to Janssen Global Services, LLC. Dr Saade received consultation and speaker fees from Janssen.

Safety, Reactogenicity, Immunogenicity, and Dose Selection of 10-Valent Extraintestinal Pathogenic Escherichia coli Bioconjugate Vaccine (VAC52416) in Adults Aged 60-85 Years in a Randomized, Multicenter, Interventional, First-in-Human, Phase 1/2a Study

Background

ExPEC10V is a bioconjugate vaccine containing O-antigen polysaccharides of 10 extraintestinal pathogenic Escherichia coli (ExPEC) serotypes. This phase 1/2a study (NCT03819049) assessed the safety, reactogenicity, and immunogenicity of ExPEC10V (VAC52416) to prevent invasive E coli disease in elderly adults.

Methods

The observer-blind, active-controlled design included a 28-day screening, vaccination, 181-day follow-up, and 1-year follow-up. Participants (60-85 years of age) were randomized to ExPEC10V low dose (antigen dose range, 4-8 µg), ExPEC10V medium dose (4-16 µg), or ExPEC10V high dose (8-16 µg); 4-valent ExPEC vaccine (ExPEC4V); or 13-valent pneumococcal conjugate vaccine (PCV13). The incidence of adverse events (AEs; solicited, day 15; unsolicited, day 30; serious AEs, day 181) and immunogenicity (electrochemiluminescent-based assay [ECL] and multiplex opsonophagocytic assay [MOPA]) were assessed. Optimal ExPEC10V dose was determined from safety data through day 30 and an immunogenicity dose selection algorithm based on day 15 ECL and MOPA results.

Results

A total of 416 participants were included (median age, 64.0 years; 54.8% female). The incidences of solicited local and systemic AEs were, respectively, 44.2% and 39.4% for low-dose, 52.9% and 46.1% for medium-dose, 57.7% and 45.2% for high-dose ExPEC10V, and 74.1% and 48.1% for PCV13. Five serious AEs, not vaccine related, were reported. The ECL revealed a robust antibody response to ExPEC10V through year 1. Opsonophagocytic killing activity was detected against all but serotype O8; this lack of response against serotype O8 was linked to low assay sensitivity. Based on the totality of data, high-dose ExPEC10V was considered optimal.

Conclusions

ExPEC10V was well tolerated and immunogenic in elderly adults against all but serotype O8.