SARS-CoV-2 mRNA vaccination and short-term changes in viral load and CD4/CD8 T cell counts in people living with HIV

OBJECTIVES

To investigate if SARS-CoV-2 mRNA vaccination has an impact on HIV-related viro-immunological parameters.

METHODS

PWH of the VAXICONA-ORCHESTRA cohort who received ≥1 dose of SARS-CoV-2 mRNA vaccine and for whom paired measures of immuno-virological markers [Viral Load (VL), CD4, CD8 count 1 month before and after a vaccine dose (VD)] were available, were included. Paired t-test and generalized estimating equation linear regression analyses were used to study changes over ± 1 month around the VD. Subgroup analyses were performed.

RESULTS

510 PWH enrolled: median age 55 y (IQR 46-60), CD4 and CD8 count 489(287-719) and 790 (59-1104) cells/mm3. 81% received 3 VDs. After a median of 28 days (3-53) from VD, CD4 count increased by +15 cells/mm3 (SD ±129.7; p=0.001), CD8 by +12 (±250.5; p=0.199), VL decreased by -0.11 log10 (±0.88; p=0.001). Similar results were observed after restricting the analysis to viro-suppressed PWH, with CD4 ≤200/mm3, more than 6 months of ART before VD and after excluding previous COVID-19.

CONCLUSIONS

A small significant increase in CD4 count and a negligible drop in HIV-RNA were observed. Our findings are consistent with the hypothesis that SARS-CoV-2 mRNA vaccine can prime CD4 T spike specific cells even in the more immuno-compromised PWH.

Sepsis-related mortality: long-term trends in Northeastern Italy, including pandemic years

BACKGROUND

Global estimates of sepsis mortality are based on multiple causes of death (MCOD, any mention of the condition on death certificates); however, MCOD data are sparse and mainly referring to the pre-pandemic period.

OBJECTIVES

To investigate recent trends in sepsis-related mortality, associated sites of infection, and comorbidities in Veneto (Northeastern Italy).

METHODS

Mortality records from 2008 to 2022 were extracted, and sepsis-related mortality was assessed based both on the underlying cause of death (UCOD) and on MCOD. The average annual percent change in age-standardised rates was estimated by join point regression through the whole study period. MCOD records were investigated to retrieve infection sites and comorbidities.

RESULTS

Sepsis was mentioned in 63,479 death certificates, growing from 4.9% out of all deaths in 2008 to 12.9% in 2022. Age-standardised mortality rates increased yearly by 8.2% (95%CI 2.1-14.7%) based on the UCOD and by 5.9% (95%CI 5.3-6.5%) based on MCOD. Sharp peaks in monthly mortality were observed in correspondence with flu epidemics, COVID-19 pandemic waves, and periods of extreme heat. The percentage of sepsis-related deaths associated to urinary tract infections, and with mention of neurodegenerative disorders and chronic kidney disease increased over time.

CONCLUSION

Raised awareness of physicians, ageing of the population, spread of antimicrobial resistance further fuelled by the COVID-19 pandemic are among reasons of increasing sepsis-related mortality in Italy. Continuous monitoring of sepsis by means of MCOD data and other surveillance tools is warranted.

Perspectives of European Patient Advocacy Groups on Volunteer Registries and Vaccine Trials: VACCELERATE Survey Study

BACKGROUND

The VACCELERATE Pan-European Scientific network aims to strengthen the foundation of vaccine trial research across Europe by following the principles of equity, inclusion, and diversity. The VACCELERATE Volunteer Registry network provides access to vaccine trial sites across the European region and supports a sustainable volunteer platform for identifying potential participants for forthcoming vaccine clinical research.

OBJECTIVE

The aim of this study was to approach members of patient advocacy groups (PAGs) across Europe to assess their willingness to register for the VACCELERATE Volunteer Registry and their perspectives related to participating in vaccine trials.

METHODS

In an effort to understand how to increase recruitment for the VACCELERATE Volunteer Registry, a standardized survey was developed in English and translated into 8 different languages (Dutch, English, French, German, Greek, Italian, Spanish, and Swedish) by the respective National Coordinator team. The online, anonymous survey was circulated, from March 2022 to May 2022, to PAGs across 10 European countries (Belgium, Cyprus, Denmark, France, Germany, Greece, Ireland, Italy, Spain, and Sweden) to share with their members. The questionnaire constituted of multiple choice and open-ended questions evaluating information regarding participants' perceptions on participating in vaccine trials and their willingness to become involved in the VACCELERATE Volunteer Registry.

RESULTS

In total, 520 responses were collected and analyzed. The PAG members reported that the principal criteria influencing their decision to participate in clinical trials overall are (1) the risks involved, (2) the benefits that will be gained from their potential participation, and (3) the quality and quantity of information provided regarding the trial. The survey revealed that, out of the 520 respondents, 133 individuals across all age groups were "positive" toward registering in the VACCELERATE Volunteer Registry, with an additional 47 individuals reporting being "very positive." Respondents from Northern European countries were 1.725 (95% CI 1.206-2.468) times more likely to be willing to participate in the VACCELERATE Volunteer Registry than respondents from Southern European countries.

CONCLUSIONS

Factors discouraging participants from joining vaccine trial registries or clinical trials primarily include concerns of the safety of novel vaccines and a lack of trust in those involved in vaccine development. These outcomes aid in identifying issues and setbacks in present registries, providing the VACCELERATE network with feedback on how to potentially increase participation and enrollment in trials across Europe. Development of European health communication strategies among diverse public communities, especially via PAGs, is the key for increasing patients' willingness to participate in clinical studies.

WHO's essential medicines and AWaRe: recommendations on first- and second-choice antibiotics for empiric treatment of clinical infections

The WHO Model List of Essential Medicines (EML) prioritizes medicines that have significant global public health value. The EML can also deliver important messages on appropriate medicine use. Since 2017, in response to the growing challenge of antimicrobial resistance, antibiotics on the EML have been reviewed and categorized into three groups: Access, Watch, and Reserve, leading to a new categorization called AWaRe. These categories were developed taking into account the impact of different antibiotics and classes on antimicrobial resistance and the implications for their appropriate use. The 2023 AWaRe classification provides empirical guidance on 41 essential antibiotics for over 30 clinical infections targeting both the primary health care and hospital facility setting. A further 257 antibiotics not included on the EML have been allocated an AWaRe group for stewardship and monitoring purposes. This article describes the development of AWaRe, focussing on the clinical evidence base that guided the selection of Access, Watch, or Reserve antibiotics as first and second choices for each infection. The overarching objective was to offer a tool for optimizing the quality of global antibiotic prescribing and reduce inappropriate use by encouraging the use of Access antibiotics (or no antibiotics) where appropriate. This clinical evidence evaluation and subsequent EML recommendations are the basis for the AWaRe antibiotic book and related smartphone applications. By providing guidance on antibiotic prioritization, AWaRe aims to facilitate the revision of national lists of essential medicines, update national prescribing guidelines, and supervise antibiotic use. Adherence to AWaRe would extend the effectiveness of current antibiotics while helping countries expand access to these life-saving medicines for the benefit of current and future patients, health professionals, and the environment.

Challenges for a broad international implementation of the current severe community-acquired pneumonia guidelines

Severe community-acquired pneumonia (sCAP) remains one of the leading causes of admission to the intensive care unit, thus consuming a large share of resources and is associated with high mortality rates worldwide. The evidence generated by clinical studies in the last decade was translated into recommendations according to the first published guidelines focusing on severe community-acquired pneumonia. Despite the advances proposed by the present guidelines, several challenges preclude the prompt implementation of these diagnostic and therapeutic measures. The present article discusses the challenges for the broad implementation of the sCAP guidelines and proposes solutions when applicable.

Excess resource use and cost of drug-resistant infections for six key pathogens in Europe: a systematic review and Bayesian meta-analysis

BACKGROUND

Quantifying the resource use and cost of antimicrobial resistance establishes the magnitude of the problem and drives action.

OBJECTIVES

Assessment of resource use and cost associated with infections with six key drug-resistant pathogens in Europe.

METHODS

A systematic review and Bayesian meta-analysis.

DATA SOURCES

MEDLINE (Ovid), Embase (Ovid), Econlit databases, and grey literature for the period 1 January 1990, to 21 June 2022.

STUDY ELIGIBILITY CRITERIA

Resource use and cost outcomes (including excess length of stay, overall costs, and other excess in or outpatient costs) were compared between patients with defined antibiotic-resistant infections caused by carbapenem-resistant (CR) Pseudomonas aeruginosa and Acinetobacter baumannii, CR or third-generation cephalosporin Escherichia coli (3GCREC) and Klebsiella pneumoniae, methicillin-resistant Staphylococcus aureus, and vancomycin-resistant Enterococcus faecium, and patients with drug-susceptible or no infection.

PARTICIPANTS

All patients diagnosed with drug-resistant bloodstream infections (BSIs).

INTERVENTIONS

NA.

ASSESSMENT OF RISK OF BIAS

An adapted version of the Joanna Briggs Institute assessment tool, incorporating case-control, cohort, and economic assessment frameworks.

METHODS OF DATA SYNTHESIS

Hierarchical Bayesian meta-analyses were used to assess pathogen-specific resource use estimates.

RESULTS

Of 5969 screened publications, 37 were included in the review. Data were sparse and heterogeneous. Most studies estimated the attributable burden by, comparing resistant and susceptible pathogens (32/37). Four studies analysed the excess cost of hospitalization attributable to 3GCREC BSIs, ranging from -€ 2465.50 to € 6402.81. Eight studies presented adjusted excess length of hospital stay estimates for methicillin-resistant S. aureus and 3GCREC BSIs (4 each) allowing for Bayesian hierarchical analysis, estimating means of 1.26 (95% credible interval [CrI], -0.72 to 4.17) and 1.78 (95% CrI, -0.02 to 3.38) days, respectively.

CONCLUSIONS

Evidence on most cost and resource use outcomes and across most pathogen-resistance combinations was severely lacking. Given the importance of this evidence for rational policymaking, further research is urgently needed.

A systematic review on the excess health risk of antibiotic-resistant bloodstream infections for six key pathogens in Europe

BACKGROUND

Antimicrobial resistance is a global threat, which requires novel intervention strategies, for which priority pathogens and settings need to be determined.

OBJECTIVES

We evaluated pathogen-specific excess health burden of drug-resistant bloodstream infections (BSIs) in Europe.

METHODS

A systematic review and meta-analysis.

DATA SOURCES

MEDLINE, Embase, and grey literature for the period January 1990 to May 2022.

STUDY ELIGIBILITY CRITERIA

Studies that reported burden data for six key drug-resistant pathogens: carbapenem-resistant (CR) Pseudomonas aeruginosa and Acinetobacter baumannii, third-generation cephalosporin or CR Escherichia coli and Klebsiella pneumoniae, methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium. Excess health outcomes compared with drug-susceptible BSIs or uninfected patients. For MRSA and third-generation cephalosporin E. coli and K. pneumoniae BSIs, five or more European studies were identified. For all others, the search was extended to high-income countries.

PARTICIPANTS

Paediatric and adult patients diagnosed with drug-resistant BSI.

INTERVENTIONS

Not applicable.

ASSESSMENT OF RISK OF BIAS

An adapted version of the Joanna-Briggs Institute assessment tool.

METHODS OF DATA SYNTHESIS

Random-effect models were used to pool pathogen-specific burden estimates.

RESULTS

We screened 7154 titles, 1078 full-texts and found 56 studies on BSIs. Most studies compared outcomes of drug-resistant to drug-susceptible BSIs (46/56, 82.1%), and reported mortality (55/56 studies, 98.6%). The pooled crude estimate for excess all-cause mortality of drug-resistant versus drug-susceptible BSIs ranged from OR 1.31 (95% CI 1.03-1.68) for CR P. aeruginosa to OR 3.44 (95% CI 1.62-7.32) for CR K. pneumoniae. Pooled crude estimates comparing mortality to uninfected patients were available for vancomycin-resistant Enterococcus and MRSA BSIs (OR of 11.19 [95% CI 6.92-18.09] and OR 6.18 [95% CI 2.10-18.17], respectively).

CONCLUSIONS

Drug-resistant BSIs are associated with increased mortality, with the magnitude of the effect influenced by pathogen type and comparator. Future research should address crucial knowledge gaps in pathogen- and infection-specific burdens to guide development of novel interventions.

Frequency of bloodstream infections caused by six key antibiotic-resistant pathogens for prioritization of research and discovery of new therapies in Europe: a systematic review

BACKGROUND

To prioritize healthcare investments, ranking of infections caused by antibiotic-resistant bacteria should be based on accurate incidence data.

OBJECTIVES

We performed a systematic review to estimate frequency measures of antimicrobial resistance for six key bacteria causing bloodstream infections (BSI) in European countries.

DATA SOURCES

We searched PubMed, Web of Science, Embase databases, and the ECRAID-Base Epidemiological-Network platform.

STUDY ELIGIBILITY CRITERIA

We included studies and surveillance systems assessing resistance-percentage, prevalence, or incidence-density of BSI because of carbapenem-resistant Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, and Escherichia coli, third-generation cephalosporins-resistant E. coli and K. pneumoniae, vancomycin-resistant Enterococcus faecium, and methicillin-resistant Staphylococcus aureus.

METHODS

Reviewers independently assessed published data and evaluated study quality with the modified Joanna Briggs Institute critical appraisal tool. Pooled estimates were determined using random effects meta-analysis. Consistency of data was assessed using random effects meta-regression (Wald test, p > 0.05).

RESULTS

We identified 271 studies and 52 surveillance systems from 32 European countries. Forty-five studies (16%) reported on BSI, including 180 frequency measures most commonly as resistance-percentage (88, 48.9%). Among 309 frequency measures extracted from 24 (46%) surveillance systems, 278 (89%) were resistance-percentages. Frequency measures of methicillin-resistant S. aureus and vancomycin-resistant E. faecium BSI were more frequently reported from Southern Europe and Western Europe (80%), whereas carbapenem-resistant P. aeruginosa BSI from Northern Europe and Western Europe (88%). Highest resistance-percentages were detected for carbapenem-resistant A. baumannii (66% in Central Eastern Europe) and carbapenem-resistant K. pneumoniae (62.8% in Southern Europe). Pooled estimates showed lower resistance-percentages in community versus healthcare-associated infections and in children versus adults. Estimates from studies and surveillance systems were mostly consistent among European regions. The included data was of medium quality.

DISCUSSION

Pathogen-specific frequency measures of antimicrobial resistance in BSI are insufficient to inform antibiotic stewardship and research and development strategies. Improving data collection and standardization of frequency measures is urgently needed.

Regional spread of an atypical ESBL-producing Escherichia coli ST131H89 clone among different human and environmental reservoirs in Western Switzerland

We describe the inter-regional spread of a novel ESBL-producing Escherichia coli subclone (ST131H89) in long-term care facility residents, general population, and environmental water sources in Western Switzerland between 2017 and 2020. The study highlights the importance of molecular surveillance for tracking emerging antibiotic-resistant pathogens in healthcare and community settings.

How to tailor recommendations on the treatment of multi-drug resistant Gram-negative infections at country level integrating antibiotic stewardship principles within the GRADE-ADOLOPMENT framework

Promoting the optimal use of antibiotics through evidence-based recommendations should be regarded as a crucial step in the global fight against antimicrobial resistance. Within this scope, several guidelines and guidance documents for antibiotic therapy have been published in recent years. All documents underline the limitations of existing evidence and remark on the need for tailoring recommendations at the national level, based on local epidemiology, availability of diagnostics and drugs, and antimicrobial stewardship principles. The GRADE-ADOLOPMENT methodology is an evidence-based methodology that allows the adoption, adaptation, and update of existing recommendations to specific settings without performing de novo systematic reviews and grading of the evidence. However, procedures to integrate this evidence with stewardship principles, countries' surveillance data, and capacity in terms of diagnostics and antibiotics' availability have never been defined. This Personal View provides the first example of a country's calibration of international evidence-based guidance documents on treating infections caused by multidrug-resistant bacteria. A panel of experts convened by the Italian Medicine Agency (AIFA) used the GRADE methodology for systematically extracting and evaluating 100 recommendations on the treatment of infections due to multidrug-resistant Gram-negative bacteria from 11 guidance documents and 24 systematic reviews. The ADOLOPMENT procedure was used to calibrate the existing recommendations to the national context, leading to the adoption of 64, the adaptation of 27, and the rejection of nine recommendations. We discuss the technical details of the GRADE-ADOLOPMENT application, the calibration process, and the human resources required to support such an effort. This Personal View also covers the challenges of integrating antibiotic stewardship principles in evidence-based recommendations for treating infections with very limited therapeutic and diagnostic options. The details presented here could support the easy transferability of the methodology to other countries and settings, particularly where the incidence of antibiotic-resistant infections is high.

Enforcing surveillance of antimicrobial resistance and antibiotic use to drive stewardship: experience in a paediatric setting

BACKGROUND

Antibiotic stewardship (AS) interventions in paediatrics are still not standardized regarding methodology, metrics, and outcomes. We report the results of an AS intervention in the paediatric area based on education and guideline provision via an electronic App.

MATERIALS AND METHODS

The AS intervention was conducted in 2021 through observation, education, audit and feedback and provision of an electronic App (Firstline.org) to support antibiotic prescription based on local susceptibility data. The primary outcome was the antibiotic consumption in the 12 months following the intervention (year 2022) compared with a historical 12-month control (year 2019) via an interrupted time series analysis. Secondary outcomes were appropriateness of therapy, length of stay, 30-day readmission, transfers to the paediatric intensive care unit, in-hospital mortality, and prevalence of antimicrobial resistance (AMR).

RESULTS

During the post-intervention phase, 29 cross-sectional audits and feedback were conducted including 467 patients. Prescriptions were appropriate according to the guidelines in 85.7% of cases, with a stable trend over time. A significant decrease in antibiotic consumption was measured in terms of defined daily doses per 1000 patient days (-222.13; P<0.001) and days of therapy per 1000 patient days (-452.49; P<0.001) in the post-intervention period with a clear inversion of the Access to Watch ratio (from 0.7 to 1.7). Length of stay, in-hospital mortality, intensive care unit transfers, and incidence of AMR infections remained stable, while 30-day readmission decreased from 4.9 per 100 admissions to 2.8 per 100 admissions (P<0.001).

CONCLUSIONS

The intervention was associated with a significant reduction in antimicrobial consumption and an increase in the appropriateness of prescriptions. Electronic tools can be of value in promoting adherence to guidelines and ensuring the sustainability of results.

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.

Gut Microbiome Disruption Following SARS-CoV-2: A Review

COVID-19 has been associated with having a negative impact on patients' gut microbiome during both active disease and in the post-acute phase. In acute COVID-19, rapid alteration of the gut microbiome composition was observed, showing on one side a reduction in beneficial symbionts (e.g., Roseburia, Lachnospiraceae) and on the other side an increase in opportunistic pathogens such as Enterococcus and Proteobacteria. Alpha diversity tends to decrease, especially initially with symptom onset and hospital admission. Although clinical recovery appears to align with improved gut homeostasis, this process could take several weeks, even in mild infections. Moreover, patients with COVID-19 post-acute syndrome showed changes in gut microbiome composition, with specific signatures associated with decreased respiratory function up to 12 months following acute disease. Potential treatments, especially probiotic-based therapy, are under investigation. Open questions remain on the possibility to use gut microbiome data to predict disease progression and on potential confounders that may impair result interpretation (e.g., concomitant therapies in the acute phase; reinfection, vaccines, and occurrence of novel conditions or diseases in the post-acute syndrome). Understanding the relationships between gut microbiome dynamics and disease progression may contribute to better understanding post-COVID syndrome pathogenesis or inform personalized treatment that can affect specific targets or microbiome markers.

The Challenges of Vaccine Trial Participation among Underserved and Hard-to-Reach Communities: An Internal Expert Consultation of the VACCELERATE Consortium

Underserved and hard-to-reach population groups are under-represented in vaccine trials. Thus, we aimed to identify the challenges of vaccine trial participation of these groups in member countries of the VACCELERATE network. Seventeen National Coordinators (NC), each representing their respective country (15 European countries, Israel, and Turkey), completed an online survey. From 15 eligible groups, those that were more frequently declared underserved/hard-to-reach in vaccine research were ethnic minorities (76.5%), persons experiencing homelessness (70.6%), illegal workers and refugees (64.7%, each). When prioritization for education on vaccine trials was considered, ethnic groups, migrants, and immigrants (5/17, 29.4%) were the groups most frequently identified by the NC as top targets. The most prominent barriers in vaccine trial participation affecting all groups were low levels of health literacy, reluctance to participate in trials due to engagement level, and low levels of trust in vaccines/vaccinations. This study highlighted population groups considered underserved/hard-to-reach in countries contained within the European region, and the respective barriers these groups face when participating in clinical studies. Our findings aid with the design of tailored interventions (within-and across-countries of the European region) and with the development of strategies to overcome major barriers in phase 2 and phase 3 vaccine trial participation.

Ventilatory associated barotrauma in COVID-19 patients: A multicenter observational case control study (COVI-MIX-study)

BACKGROUND

The risk of barotrauma associated with different types of ventilatory support is unclear in COVID-19 patients. The primary aim of this study was to evaluate the effect of the different respiratory support strategies on barotrauma occurrence; we also sought to determine the frequency of barotrauma and the clinical characteristics of the patients who experienced this complication.

METHODS

This multicentre retrospective case-control study from 1 March 2020 to 28 February 2021 included COVID-19 patients who experienced barotrauma during hospital stay. They were matched with controls in a 1:1 ratio for the same admission period in the same ward of treatment. Univariable and multivariable logistic regression (OR) were performed to explore which factors were associated with barotrauma and in-hospital death.

RESULTS

We included 200 cases and 200 controls. Invasive mechanical ventilation was used in 39.3% of patients in the barotrauma group, and in 20.1% of controls (p<0.001). Receiving non-invasive ventilation (C-PAP/PSV) instead of conventional oxygen therapy (COT) increased the risk of barotrauma (OR 5.04, 95% CI 2.30 - 11.08, p<0.001), similarly for invasive mechanical ventilation (OR 6.24, 95% CI 2.86-13.60, p<0.001). High Flow Nasal Oxygen (HFNO), compared with COT, did not significantly increase the risk of barotrauma. Barotrauma frequency occurred in 1.00% [95% CI 0.88-1.16] of patients; these were older (p=0.022) and more frequently immunosuppressed (p=0.013). Barotrauma was shown to be an independent risk for death (OR 5.32, 95% CI 2.82-10.03, p<0.001).

CONCLUSIONS

C-PAP/PSV compared with COT or HFNO increased the risk of barotrauma; otherwise HFNO did not. Barotrauma was recorded in 1.00% of patients, affecting mainly patients with more severe COVID-19 disease. Barotrauma was independently associated with mortality.

TRIAL REGISTRATION

this case-control study was prospectively registered in clinicaltrial.gov as NCT04897152 (on 21 May 2021).

SARS-CoV-2 mRNA Vaccine Response in People Living with HIV According to CD4 Count and CD4/CD8 Ratio

BACKGROUND

Our aim was to estimate the rates of not achieving a robust/above-average humoral response to the COVID-19 mRNA vaccine in people living with HIV (PLWH) who received ≥2 doses and to investigate the role of the CD4 and CD4/CD8 ratio in predicting the humoral response.

METHODS

We evaluated the humoral anti-SARS-CoV-2 response 1-month after the second and third doses of COVID-19 mRNA vaccine as a proportion of not achieving a robust/above-average response using two criteria: (i) a humoral threshold identified as a correlate of protection against SARS-CoV-2 (<90% vaccine efficacy): anti-RBD < 775 BAU/mL or anti-S < 298 BAU/mL, (ii) threshold of binding antibodies equivalent to average neutralization activity from the levels of binding (nAb titer < 1:40): anti-RBD < 870 BAU/mL or anti-S < 1591 BAU/mL. PLWH were stratified according to the CD4 count and CD4/CD8 ratio at first dose. Logistic regression was used to compare the probability of not achieving robust/above-average responses. A mixed linear model was used to estimate the mean anti-RBD titer at various time points across the exposure groups.

RESULTS

a total of 1176 PLWH were included. The proportions of participants failing to achieve a robust/above-average response were significantly higher in participants with a lower CD4 and CD4/CD8 ratio, specifically, a clearer gradient was observed for the CD4 count. The CD4 count was a better predictor of the humoral response of the primary cycle than ratio. The third dose was pivotal in achieving a robust/above-average humoral response, at least for PLWH with CD4 > 200 cells/mm3 and a ratio > 0.6.

CONCLUSIONS

A robust humoral response after a booster dose has not been reached by 50% of PLWH with CD4 < 200 cells mm3. In the absence of a validated correlate of protections in the Omicron era, the CD4 count remains the most solid marker to guide vaccination campaigns in PLWH.

MOSAIC: A cohort study of human mpox virus disease

Background

Human mpox is a viral disease caused by an Orthopoxvirus, human mpox virus (hMPXV), typically causing fever and a rash. Mpox has historically been endemic to parts of Central and West Africa, with small numbers of imported cases reported elsewhere, but starting May 2022 an unprecedented global outbreak caused by clade IIb hMPXV was reported outside traditionally endemic countries. This prompted the initiation of MOSAIC, a cohort study implemented in Europe and Asia that aims to describe clinical and virologic outcomes of PCR-confirmed hMPXV disease, including those who receive antiviral therapy. The study is ongoing.

Methods

MOSAIC recruits participants of any age with laboratory-confirmed mpox disease who provide informed consent. Participants enrol in the cohort for a total of six months. Blood, lesion and throat samples are collected at several timepoints from the day of diagnosis or the first day of treatment (Day 1) until Day 28 for PCR detection of hMPXV. Clinical data are collected by clinicians and participants ( via a self-completion questionnaire) for six months to characterize the signs and symptoms associated with the illness, as well as short- and more long-term outcomes.

Discussion

The design and prompt implementation of clinical research response is key in addressing emerging outbreaks. MOSAIC began enrolment within two months of the start of the international mpox epidemic. While the number of cases is now low, the study remains open for inclusion.

ICTRP registration

EU CT number: 2022-501132-42-00 (22/06/2022).

Ten golden rules for optimal antibiotic use in hospital settings: the WARNING call to action

Antibiotics are recognized widely for their benefits when used appropriately. However, they are often used inappropriately despite the importance of responsible use within good clinical practice. Effective antibiotic treatment is an essential component of universal healthcare, and it is a global responsibility to ensure appropriate use. Currently, pharmaceutical companies have little incentive to develop new antibiotics due to scientific, regulatory, and financial barriers, further emphasizing the importance of appropriate antibiotic use. To address this issue, the Global Alliance for Infections in Surgery established an international multidisciplinary task force of 295 experts from 115 countries with different backgrounds. The task force developed a position statement called WARNING (Worldwide Antimicrobial Resistance National/International Network Group) aimed at raising awareness of antimicrobial resistance and improving antibiotic prescribing practices worldwide. The statement outlined is 10 axioms, or "golden rules," for the appropriate use of antibiotics that all healthcare workers should consistently adhere in clinical practice.

The incidence and risk factors of selected drug prescriptions and outpatient care after SARS-CoV-2 infection in low-risk subjects: a multicenter population-based cohort study

Background

Knowledge about the dynamics of transmission of SARS-CoV-2 and the clinical aspects of COVID-19 has steadily increased over time, although evidence of the determinants of disease severity and duration is still limited and mainly focused on older adult and fragile populations.

Methods

The present study was conceived and carried out in the Emilia-Romagna (E-R) and Veneto Regions, Italy, within the context of the EU's Horizon 2020 research project called ORCHESTRA (Connecting European Cohorts to increase common and effective response to SARS-CoV-2 pandemic) (www.orchestra-cohort.eu). The study has a multicenter retrospective population-based cohort design and aimed to investigate the incidence and risk factors of access to specific healthcare services (outpatient visits and diagnostics, drug prescriptions) during the post-acute phase from day-31 to day-365 after SARS-CoV-2 infection, in a healthy population at low risk of severe acute COVID-19. The study made use of previously recorded large-scale healthcare data available in the administrative databases of the two Italian Regions. The statistical analysis made use of methods for competing risks. Risk factors were assessed separately in the two Regions and results were pooled using random effects meta-analysis.

Results

There were 35,128 subjects in E-R and 88,881 in Veneto who were included in the data analysis. The outcome (access to selected health services) occurred in a high percentage of subjects in the post-acute phase (25% in E-R and 21% in Veneto). Outpatient care was observed more frequently than drug prescriptions (18% vs. 12% in E-R and 15% vs. 10% in Veneto). Risk factors associated with the outcome were female sex, age greater than 40 years, baseline risk of hospitalization and death, moderate to severe acute COVID-19, and acute extrapulmonary complications.

Conclusion

The outcome of interest may be considered as a proxy for long-term effects of COVID-19 needing clinical attention. Our data suggest that this outcome occurs in a substantial percentage of cases, even among a previously healthy population with low or mild severity of acute COVID-19. The study results provide useful insights into planning COVID-19-related services.

Detection of SARS-CoV-2 Δ426 ORF8 Deletion Mutant Cluster in NGS Screening

Next-generation sequencing (NGS) from SARS-CoV-2-positive swabs collected during the last months of 2022 revealed a large deletion spanning ORF7b and ORF8 (426 nt) in six patients infected with the BA.5.1 Omicron variant. This extensive genome loss removed a large part of these two genes, maintaining in frame the first 22 aminoacids of ORF7b and the last three aminoacids of ORF8. Interestingly, the deleted region was flanked by two small repeats, which were likely involved in the formation of a hairpin structure. Similar rearrangements, comparable in size and location to the deletion, were also identified in 15 sequences in the NCBI database. In this group, seven out of 15 cases from the USA and Switzerland presented both the BA.5.1 variant and the same 426 nucleotides deletion. It is noteworthy that three out of six cases were detected in patients with immunodeficiency, and it is conceivable that this clinical condition could promote the replication and selection of these mutations.

Modelling antimicrobial resistance transmission to guide personalized antimicrobial stewardship interventions and infection control policies in healthcare setting: a pilot study

Infection control programs and antimicrobial stewardship have been proven effective in reducing the burden of diseases due to multidrug-resistant organisms, but quantifying the effect of each intervention is an open issue. For this aim, we propose a model to characterize the effect of interventions at single ward level. We adapted the Ross-Macdonald model to describe hospital cross-transmission dynamics of carbapenem resistant Klebsiella pneumoniae (CRKP), considering healthcare workers as the vectors transmitting susceptible and resistant pathogens among admitted patients. The model parameters were estimated from a literature review, further adjusted to reproduce observed clinical outcomes, and validated using real life data from a 2-year study in a university hospital. The model has been further explored through extensive sensitivity analysis, in order to assess the relevance of single interventions as well as their synergistic effects. Our model has been shown to be an effective tool to describe and predict the impact of interventions in reducing the prevalence of CRKP colonisation and infection, and can be extended to other specific hospital and pathological scenarios to produce tailored estimates of the most effective strategies.

Personalized infection prevention and control: a concept whose time has arrived

Personalized medicine has been progressively implemented in several diagnostic and therapeutic patients' algorithms, based on the common assumption that tailoring interventions, practices, and/or therapies to individual patients' clinical, biological, epidemiological, and genetic characteristics would optimize their effectiveness and reduce adverse effects. The potential benefit of the precision medicine approach has been recently considered for possible implementation in the field of infection prevention and control. The commentary explores available evidence and assesses possible future scenarios where, through advanced modeling approaches, we would be able to provide personalized prediction algorithms identifying at-risk patients who deserve the implementation of tailored preventive measures.

Association of ward-level antibiotic consumption with healthcare-associated Clostridioides difficile infections: an ecological study in five German university hospitals, 2017-2019

OBJECTIVES

To analyse the influence of antibiotic consumption on healthcare-associated healthcare onset (HAHO) Clostridioides difficile infection (CDI) in a German university hospital setting.

METHODS

Monthly ward-level antibiotic consumption measured in DDD/100 patient days (pd) and CDI surveillance data from five university hospitals in the period 2017 through 2019 were analysed. Uni- and multivariable analyses were performed with generalized estimating equation models.

RESULTS

A total of 225 wards with 7347 surveillance months and 4 036 602 pd participated. With 1184 HAHO-CDI cases, there was a median incidence density of 0.17/1000 pd (IQR 0.03-0.43) across all specialties, with substantial differences among specialties. Haematology-oncology wards showed the highest median incidence density (0.67/1000 pd, IQR 0.44-1.01), followed by medical ICUs (0.45/1000 pd, IQR 0.27-0.73) and medical general wards (0.32/1000 pd, IQR 0.18-0.53). Multivariable analysis revealed carbapenem (mostly meropenem) consumption to be the only antibiotic class associated with increased HAHO-CDI incidence density. Each carbapenem DDD/100 pd administered increased the HAHO-CDI incidence density by 1.3% [incidence rate ratio (IRR) 1.013; 95% CI 1.006-1.019]. Specialty-specific analyses showed this influence only to be valid for haematological-oncological wards. Overall, factors like ward specialty (e.g. haematology-oncology ward IRR 2.961, 95% CI 2.203-3.980) or other CDI cases on ward had a stronger influence on HAHO-CDI incidence density (e.g. community-associated CDI or unknown association case in same month IRR 1.476, 95% CI 1.242-1.755) than antibiotic consumption.

CONCLUSIONS

In the German university hospital setting, monthly ward-level carbapenem consumption seems to increase the HAHO-CDI incidence density predominantly on haematological-oncological wards. Furthermore, other patient-specific factors seem to be equally important to control HAHO-CDI.

Accessibility of covariance information creates vulnerability in Federated Learning frameworks

MOTIVATION

Federated Learning (FL) is gaining traction in various fields as it enables integrative data analysis without sharing sensitive data, such as in healthcare. However, the risk of data leakage caused by malicious attacks must be considered. In this study, we introduce a novel attack algorithm that relies on being able to compute sample means, sample covariances, and construct known linearly independent vectors on the data owner side.

RESULTS

We show that these basic functionalities, which are available in several established FL frameworks, are sufficient to reconstruct privacy-protected data. Additionally, the attack algorithm is robust to defense strategies that involve adding random noise. We demonstrate the limitations of existing frameworks and propose potential defense strategies analyzing the implications of using differential privacy. The novel insights presented in this study will aid in the improvement of FL frameworks.

AVAILABILITY AND IMPLEMENTATION

The code examples are provided at GitHub (https://github.com/manuhuth/Data-Leakage-From-Covariances.git). The CNSIM1 dataset, which we used in the manuscript, is available within the DSData R package (https://github.com/datashield/DSData/tree/main/data).

Exploring the Use of Monoclonal Antibodies and Antiviral Therapies for Early Treatment of COVID-19 Outpatients in a Real-World Setting: A Nationwide Study from England and Italy

BACKGROUND

Real-world data on early treatment of coronavirus disease 2019 (COVID-19) outpatients with newly approved therapies are sparse.

AIM

To explore the pattern of use of monoclonal antibodies (mAbs)/antiviral therapies approved for early COVID-19 treatment in non-hospitalized patients from England and Italy from December 2021 to October 2022.

METHODS

Public national dashboards on weekly mAb/antiviral use and/or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection diagnoses from the Italian Medicines Agency, the Italian National Institute of Health, National Health Service in England and the UK Government were explored. Prevalence of antiviral use in outpatients during the entire study period and every two weeks was calculated, as a whole and by class and compounds. An interrupted time-series (ITS) analysis was carried out to assess the impact of predominant SARS-CoV-2 variants over time on the prevalence of use of mAbs/antivirals in England and Italy.

RESULTS

Overall, 77,469 and 195,604 doses of mAbs/antivirals were respectively administered to a total of 10,630,903 (7.3 per 1000) and 18,168,365 (10.8 per 1000) patients diagnosed with SARS-CoV-2 infection in England and Italy. Prevalence of use every two weeks increased from 0.07% to 3.1% in England and 0.9% to 2.3% in Italy during the study period. Regarding individual compounds, sotrovimab (prevalence of use, 1.6%) and nirmatrelvir/ritonavir (1.6%) in England, and nirmatrelvir/ritonavir (1.7%) and molnupiravir (0.5%) in Italy, reported the highest prevalence during a 2-week period. In the ITS analysis, the transition from Delta to Omicron variant predominance was associated with a significant increase in the use of sotrovimab, molnupiravir, remdesivir and nirmatrelvir/ritonavir in both England and Italy, with a reduction of other marketed mAbs. The extent of the increase was higher in England than in Italy for all these drugs except for nirmatrelvir/ritonavir.

CONCLUSIONS

In this dual nationwide study, the prevalence of use of mAbs/antivirals against SARS-CoV-2 for early outpatients' treatment increased slowly up to 2.0-3.0% of all patients diagnosed with SARS-CoV-2 infection in both England and Italy from December 2021 to October 2022. The trend of individual drug use varied in relation to predominant SARS-CoV-2 variants with some differences across countries. In line with scientific societies' guidelines, nirmatrelvir/ritonavir was the most frequently prescribed antiviral in both countries in the most recent period.

Increasing numbers and complexity of Staphylococcus aureus bloodstream infection-14 years of prospective evaluation at a German tertiary care centre with multi-centre validation of findings

OBJECTIVES

Staphylococcus aureus bloodstream infection (SAB) is a common and severe infection. This study aims to describe temporal trends in numbers, epidemiological characteristics, clinical manifestations, and outcomes of SAB.

METHODS

We performed a post-hoc analysis of three prospective SAB cohorts at the University Medical Centre Freiburg between 2006 and 2019. We validated our findings in a large German multi-centre cohort of five tertiary care centres (R-Net consortium, 2017-2019). Time-dependent trends were estimated using Poisson or beta regression models.

RESULTS

We included 1797 patients in the mono-centric and 2336 patients in the multi-centric analysis. Overall, we observed an increasing number of SAB cases over 14 years (6.4%/year and 1000 patient days, 95% CI: 5.1% to 7.7%), paralleled by an increase in the proportion of community-acquired SAB (4.9%/year [95% CI: 2.1% to 7.8%]) and a decrease in the rate of methicillin-resistant-SAB (-8.5%/year [95% CI: -11.2% to -5.6%]). All of these findings were confirmed in the multi-centre validation cohort (6.2% cases per 1000 patient cases/year [95% CI: -0.6% to 12.6%], community-acquired-SAB 8.7% [95% CI: -1.2% to 19.6%], methicillin-resistant S. aureus-SAB -18.6% [95% CI: -30.6 to -5.8%]). Moreover, we found an increasing proportion of patients with multiple risk factors for complicated/difficult-to-treat SAB (8.5%/year, 95% CI: 3.6% to 13.5%, p < 0.001), alongside an overall higher level of comorbidities (Charlson comorbidity score 0.23 points/year, 95% CI: 0.09 to 0.37, p 0.005). At the same time, the rate of deep-seated foci such as osteomyelitis or deep-seated abscesses significantly increased (6.7%, 95% CI: 3.9% to 9.6%, p < 0.001). A reduction of in-hospital mortality by 0.6% per year (95% CI: 0.08% to 1%) was observed in the subgroup of patients with infectious diseases consultations.

DISCUSSION

We found an increasing number of SAB combined with a significant increase in comorbidities and complicating factors in tertiary care centres. The resulting challenges in securing adequate SAB management in the face of high patient turnover will become an important task for physicians.

How European Research Projects Can Support Vaccination Strategies: The Case of the ORCHESTRA Project for SARS-CoV-2

ORCHESTRA ("Connecting European Cohorts to Increase Common and Effective Response To SARS-CoV-2 Pandemic") is an EU-funded project which aims to help rapidly advance the knowledge related to the prevention of the SARS-CoV-2 infection and the management of COVID-19 and its long-term sequelae. Here, we describe the early results of this project, focusing on the strengths of multiple, international, historical and prospective cohort studies and highlighting those results which are of potential relevance for vaccination strategies, such as the necessity of a vaccine booster dose after a primary vaccination course in hematologic cancer patients and in solid organ transplant recipients to elicit a higher antibody titer, and the protective effect of vaccination on severe COVID-19 clinical manifestation and on the emergence of post-COVID-19 conditions. Valuable data regarding epidemiological variations, risk factors of SARS-CoV-2 infection and its sequelae, and vaccination efficacy in different subpopulations can support further defining public health vaccination policies.

Real-life comparison of mortality in patients with SARS-CoV-2 infection at risk for clinical progression treated with molnupiravir or nirmatrelvir plus ritonavir during the Omicron era in Italy: a nationwide, cohort study

Background

Comparative data on mortality in COVID-19 patients treated with molnupiravir or with nirmatrelvir plus ritonavir are inconclusive. We therefore compared all-cause mortality in community-dwelling COVID-19 patients treated with these drugs during the Omicron era.

Methods

Data collected in the nationwide, population-based, cohort of patients registered in the database of the Italian Medicines Agency (AIFA) were used. To increase completeness of the recorded deaths and date correctness, a cross-check with the National Death Registry provided by the Ministry of the Interior was performed. We included in this study all patients infected by SARS-CoV-2 treated within 5 days after the test date and symptom onset between February 8 and April 30, 2022. All-cause mortalities by day 28 were compared between the two treatment groups after balancing for baseline characteristics using weights obtained from a gradient boosting machine algorithm.

Findings

In the considered timeframe, 17,977 patients treated with molnupiravir and 11,576 patients with nirmatrelvir plus ritonavir were included in the analysis. Most patients (25,617/29,553 = 86.7%) received a full vaccine course including the booster dose. A higher crude incidence rate of all-cause mortality was found among molnupiravir users (51.83 per 100,000 person-days), compared to nirmatrelvir plus ritonavir users (22.29 per 100,000 person-days). However, molnupiravir-treated patients were older than those treated with nirmatrelvir plus ritonavir and differences between the two populations were found as far as types of co-morbidities were concerned. For this reason, we compared the weight-adjusted cumulative incidences using the Aalen estimator and found that the adjusted cumulative incidence rates were 1.23% (95% CI 1.07%-1.38%) for molnupiravir-treated and 0.78% (95% CI 0.58%-0.98%) for nirmatrelvir plus ritonavir-treated patients (adjusted log rank p = 0.0002). Moreover, the weight-adjusted mixed-effect Cox model including Italian regions and NHS centers as random effects and treatment as the only covariate confirmed a significant reduced risk of death in patients treated with nirmatrelvir plus ritonavir. Lastly, a significant reduction in the risk of death associated with nirmatrelvir plus ritonavir was confirmed in patient subgroups, such as in females, fully vaccinated patients, those treated within day 2 since symptom onset and patients without (haemato)-oncological diseases.

Interpretation

Early initiation of nirmatrelvir plus ritonavir was associated for the first time with a significantly reduced risk of all-cause mortality by day 28 compared to molnupiravir, both in the overall population and in patient subgroups, including those fully vaccinated with the booster dose.

Funding

This study did not receive funding.

Clinical phenotypes and quality of life to define post-COVID-19 syndrome: a cluster analysis of the multinational, prospective ORCHESTRA cohort

Background

Lack of specific definitions of clinical characteristics, disease severity, and risk and preventive factors of post-COVID-19 syndrome (PCS) severely impacts research and discovery of new preventive and therapeutics drugs.

Methods

This prospective multicenter cohort study was conducted from February 2020 to June 2022 in 5 countries, enrolling SARS-CoV-2 out- and in-patients followed at 3-, 6-, and 12-month from diagnosis, with assessment of clinical and biochemical features, antibody (Ab) response, Variant of Concern (VoC), and physical and mental quality of life (QoL). Outcome of interest was identification of risk and protective factors of PCS by clinical phenotype, setting, severity of disease, treatment, and vaccination status. We used SF-36 questionnaire to assess evolution in QoL index during follow-up and unsupervised machine learning algorithms (principal component analysis, PCA) to explore symptom clusters. Severity of PCS was defined by clinical phenotype and QoL. We also used generalized linear models to analyse the impact of PCS on QoL and associated risk and preventive factors. CT registration number: NCT05097677.

Findings

Among 1796 patients enrolled, 1030 (57%) suffered from at least one symptom at 12-month. PCA identified 4 clinical phenotypes: chronic fatigue-like syndrome (CFs: fatigue, headache and memory loss, 757 patients, 42%), respiratory syndrome (REs: cough and dyspnoea, 502, 23%); chronic pain syndrome (CPs: arthralgia and myalgia, 399, 22%); and neurosensorial syndrome (NSs: alteration in taste and smell, 197, 11%). Determinants of clinical phenotypes were different (all comparisons p < 0.05): being female increased risk of CPs, NSs, and CFs; chronic pulmonary diseases of REs; neurological symptoms at SARS-CoV-2 diagnosis of REs, NSs, and CFs; oxygen therapy of CFs and REs; and gastrointestinal symptoms at SARS-CoV-2 diagnosis of CFs. Early treatment of SARS-CoV-2 infection with monoclonal Ab (all clinical phenotypes), corticosteroids therapy for mild/severe cases (NSs), and SARS-CoV-2 vaccination (CPs) were less likely to be associated to PCS (all comparisons p < 0.05). Highest reduction in QoL was detected in REs and CPs (43.57 and 43.86 vs 57.32 in PCS-negative controls, p < 0.001). Female sex (p < 0.001), gastrointestinal symptoms (p = 0.034) and renal complications (p = 0.002) during the acute infection were likely to increase risk of severe PCS (QoL <50). Vaccination and early treatment with monoclonal Ab reduced the risk of severe PCS (p = 0.01 and p = 0.03, respectively).

Interpretation

Our study provides new evidence suggesting that PCS can be classified by clinical phenotypes with different impact on QoL, underlying possible different pathogenic mechanisms. We identified factors associated to each clinical phenotype and to severe PCS. These results might help in designing pathogenesis studies and in selecting high-risk patients for inclusion in therapeutic and management clinical trials.

Funding

The study received funding from the Horizon 2020 ORCHESTRA project, grant 101016167; from the Netherlands Organisation for Health Research and Development (ZonMw), grant 10430012010023; from Inserm, REACTing (REsearch & ACtion emergING infectious diseases) consortium and the French Ministry of Health, grant PHRC 20-0424.

Using machine learning to predict antibody response to SARS-CoV-2 vaccination in solid organ transplant recipients: the multicentre ORCHESTRA cohort

OBJECTIVES

The study aim was to assess predictors of negative antibody response (AbR) in solid organ transplant (SOT) recipients after the first booster of SARS-CoV-2 vaccination.

METHODS

Solid organ transplant recipients receiving SARS-CoV-2 vaccination were prospectively enrolled (March 2021-January 2022) at six hospitals in Italy and Spain. AbR was assessed at first dose (t0), second dose (t1), 3 ± 1 month (t2), and 1 month after third dose (t3). Negative AbR at t3 was defined as an anti-receptor binding domain titre <45 BAU/mL. Machine learning models were developed to predict the individual risk of negative (vs. positive) AbR using age, type of transplant, time between transplant and vaccination, immunosuppressive drugs, type of vaccine, and graft function as covariates, subsequently assessed using a validation cohort.

RESULTS

Overall, 1615 SOT recipients (1072 [66.3%] males; mean age±standard deviation [SD], 57.85 ± 13.77) were enrolled, and 1211 received three vaccination doses. Negative AbR rate decreased from 93.66% (886/946) to 21.90% (202/923) from t0 to t3. Univariate analysis showed that older patients (mean age, 60.21 ± 11.51 vs. 58.11 ± 13.08), anti-metabolites (57.9% vs. 35.1%), steroids (52.9% vs. 38.5%), recent transplantation (<3 years) (17.8% vs. 2.3%), and kidney, heart, or lung compared with liver transplantation (25%, 31.8%, 30.4% vs. 5.5%) had a higher likelihood of negative AbR. Machine learning (ML) algorithms showing best prediction performance were logistic regression (precision-recall curve-PRAUC mean 0.37 [95%CI 0.36-0.39]) and k-Nearest Neighbours (PRAUC 0.36 [0.35-0.37]).

DISCUSSION

Almost a quarter of SOT recipients showed negative AbR after first booster dosage. Unfortunately, clinical information cannot efficiently predict negative AbR even with ML algorithms.

Risk factors for colonization with multidrug-resistant Gram-negative bacteria and Clostridioides difficile in Long Term Care Facilities (LTCFs) residents: the evidence from 27 facilities in a high endemic setting

Introduction

Residency in LTCFs increases the likelihood of colonization with multidrug resistant Gram-negative bacteria (MDR-GNB). We assessed the prevalence and risk factors for enteric colonization by III-generation cephalosporins-resistant and carbapenem-resistant (CR) GNB in a large group of LTCFs in a high endemic setting. We also assessed the prevalence and risk factors for C. difficile colonization.

Methods

A point prevalence survey with rectal screening (RS) was conducted in 27 LTCFs in north Italy. Epidemiological and clinical variables on the survey day, history of hospitalization and surgery within one year, and antibiotics within three months, were collected. The presence of III-generation cephalosporin resistant and CR GNB was assessed using a selective culture on chromogenic medium and PCR for carbapenemase detection. The presence of C. difficile was assessed using ELISA for GDH and RT-PCR to identify toxigenic strains. Multi-variable analyses were performed using two-level logistic regression models.

Results

In the study period 1947 RSs were performed. The prevalence of colonization by at least one GNB resistant to III-generation cephalosporin was 51% (E. coli 65%, K. pneumoniae 14% of isolates). The prevalence of colonization by CR GNB was 6%. 6% of all isolates (1150 strains) resulted in a carbapenem-resistant K. pneumoniae, and 3% in a carbapenem-resistant E. coli. KPC was the most frequent carbapenemase (73%) identified by PCR, followed by VIM (23%). The prevalence of colonization by C. difficile was 11.7%. The presence of a medical device (OR 2.67) and previous antibiotic use (OR 1.48) were significantly associated with III-generation cephalosporin resistant GNB colonization. The presence of a medical device (OR 2.67) and previous hospitalization (OR 1.80) were significantly associated with CR GNB. The presence of a medical device (OR 2.30) was significantly associated with C. difficile colonization. Main previously used antibiotic classes were fluoroquinolones (32% of previously treated subjects), III-generation cephalosporins (21%), and penicillins (19%).

Conclusion

Antimicrobial stewardship in LTCFs is a critical issue, being previous antibiotic treatment a risk factor for colonization by MDR-GNB. The prevalence of colonization by III-generation cephalosporin and CR GNB among LTCF residents also underlines the importance to adhere to hand hygiene indications, infection prevention and control measures, and environmental hygiene protocols, more achievable than rigorous contact precautions in this type of social setting.

Antimicrobial Stewardship in COVID-19 Patients: Those Who Sow Will Reap Even through Hard Times

BACKGROUND

Since the SARS-CoV-2 pandemic emerged, antimicrobial stewardship (AS) activities need to be diverted into COVID-19 management.

METHODS

In order to assess the impact of COVID-19 on AS activities, we analyzed changes in antibiotic consumption in moderate-to-severe COVID-19 patients admitted to four units in a tertiary-care hospital across three COVID-19 waves. The AS program was introduced at the hospital in 2018. During the first wave, COVID-19 forced the complete withdrawal of hospital AS activities. In the second wave, antibiotic guidance calibration for COVID-19 patients was implemented in all units, with enhanced stewardship activities in Units 1, 2, and 3 (intervention units). In a controlled before and after study, antimicrobial usage during the three waves of the COVID-19 pandemic was compared to the 12-month prepandemic unit (Unit 4 acted as the control). Antibiotic consumption data were analyzed as the overall consumption, stratified by the World Health Organization AWaRe classification, and expressed as defined-daily-dose (DDD) and days-of-therapy (DOT) per 1000 patient-day (PD).

RESULTS

In the first wave, the overall normalized DOT in units 2-4 significantly exceeded the 2019 level (2019: 587 DOT/1000 PD ± 42.6; Unit 2: 836 ± 77.1; Unit 3: 684 ± 122.3; Unit 4: 872, ± 162.6; p < 0.05). After the introduction of AS activities, consumption decreased in the intervention units to a significantly lower level when compared to 2019 (Unit 1: 498 DOT/1000 PD ± 49; Unit 2: 232 ± 95.7; Unit 3: 382 ± 96.9; p < 0.05). Antimicrobial stewardship activities resulted in a decreased amount of total antibiotic consumption over time and positively affected the watch class and piperacillin-tazobactam use in the involved units.

CONCLUSIONS

During a pandemic, the implementation of calibrated AS activities represents a sound investment in avoiding inappropriate antibiotic therapy.

Management of pharmacovigilance during the COVID-19 pandemic crisis by the safety department of an academic sponsor: Lessons learnt and challenges from the EU DisCoVeRy clinical trial

The current COVID-19 pandemic was an exceptional health situation, including for drug use. As there was no known effective drug for COVID-19 at the beginning of the pandemic, different drug candidates were proposed. In this article, we present the challenges for an academic Safety Department to manage the global safety of a European trial during the pandemic. The National Institute for Health and Medical Research (Inserm) conducted a European multicenter, open-label, randomized, controlled trial involving three repurposed and one-in development drugs (lopinavir/ritonavir, IFN-β1a, hydroxychloroquine, and remdesivir) in adults hospitalized with COVID-19. From 25 March 2020 to 29 May 2020, the Inserm Safety Department had to manage 585 Serious Adverse Events (SAEs) initial notification and 396 follow-up reports. The Inserm Safety Department's staff was mobilized to manage these SAEs and to report Expedited safety reports to the competent authorities within the legal timeframes. More than 500 queries were sent to the investigators due to a lack of or incoherent information on SAE forms. At the same time, the investigators were overwhelmed by the management of patients suffering from COVID-19 infection. These particular conditions of missing data and lack of accurate description of adverse events made evaluation of the SAEs very difficult, particularly the assessment of the causal role of each investigational medicinal product. In parallel, working difficulties were accentuated by the national lockdown, frequent IT tool dysfunctions, delayed implementation of monitoring and the absence of automatic alerts for SAE form modification. Although COVID-19 is a confounding factor per se, the delay in and quality of SAE form completion and the real-time medical analysis by the Inserm Safety Department were major issues in the quick identification of potential safety signals. To conduct a high-quality clinical trial and ensure patient safety, all stakeholders must take their roles and responsibilities.

VACCELERATE Site Network: Real-time definition of clinical study capacity in Europe

BACKGROUND

The inconsistent European vaccine trial landscape rendered the continent of limited interest for vaccine developers. The VACCELERATE consortium created a network of capable clinical trial sites throughout Europe. VACCELERATE identifies and provides access to state-of-the-art vaccine trial sites to accelerate clinical development of vaccines.

METHODS

Login details for the VACCELERATE Site Network (vaccelerate.eu/site-network/) questionnaire can be obtained after sending an email to. Interested sites provide basic information, such as contact details, affiliation with infectious disease networks, main area of expertise, previous vaccine trial experience, site infrastructure and preferred vaccine trial settings. In addition, sites can recommend other clinical researchers for registration in the network. If directly requested by a sponsor or sponsor representative, the VACCELERATE Site Network pre-selects vaccine trial sites and shares basic study characteristics provided by the sponsor. Interested sites provide feedback with short surveys and feasibility questionnaires developed by VACCELERATE and are connected with the sponsor to initiate the site selection process.

RESULTS

As of April 2023, 481 sites from 39 European countries have registered in the VACCELERATE Site Network. Of these, 137 (28.5 %) sites have previous experience conducting phase I trials, 259 (53.8 %) with phase II, 340 (70.7 %) with phase III, and 205 (42.6 %) with phase IV trials, respectively. Infectious diseases were reported as main area of expertise by 274 sites (57.0 %), followed by any kind of immunosuppression by 141 (29.3 %) sites. Numbers are super additive as sites may report clinical trial experience in several indications. Two hundred and thirty-one (47.0 %) sites have the expertise and capacity to enrol paediatric populations and 391 (79.6 %) adult populations. Since its launch in October 2020, the VACCELERATE Site Network has been used 21 times for academic and industry trials, mostly interventional studies, focusing on different pathogens such as fungi, monkeypox virus, Orthomyxoviridae/influenza viruses, SARS-CoV-2, or Streptococcus pneumoniae/pneumococcus.

CONCLUSIONS

The VACCELERATE Site Network enables a constantly updated Europe-wide mapping of experienced clinical sites interested in executing vaccine trials. The network is already in use as a rapid-turnaround single contact point for the identification of vaccine trials sites in Europe.

Evaluation of a ddPCR Commercial Assay for the Absolute Quantification of the Monkeypox Virus West Africa in Clinical Samples

BACKGROUND

Monkeypox virus (MPXV) is a double-stranded DNA virus belonging to the orthopoxvirus genus in the family Poxviridae. Distinct clades are identified: the clade I belonging to the Central African (or Congo Basin) clade and the subclades IIa and IIb belonging to the West African clade. Here, a commercial droplet digital PCR (ddPCR) assay was evaluated for the quantification of the MPXV West Africa clade in clinical samples.

METHODS

The ddPCR reaction was assessed as a duplex assay using RPP30 as an internal amplification control. A total of 60 clinical specimens were tested, 40 positives (skin lesions, n=10; rectal swabs, n = 10; pharyngeal swabs, n = 10; and whole blood, n = 10), and 20 negatives (n = 5 for each biological matrix) were found at the routine molecular diagnostics (orthopoxvirus qPCR followed by confirmation with Sanger sequencing). To evaluate the analytical sensitivity, the ddPCR reaction was first analyzed on serial dilutions of synthetic DNA spiked in water and in negative biological matrices, achieving a limit of detection of 3.5 copy/µL.

RESULTS

Regarding the clinical samples, compared to routine molecular diagnostics, the ddPCR duplex assay showed 100% of specificity for all biological matrices and 100% sensitivity (10/10) for lesions, 100% (10/10) for rectal swabs, 90% (9/10) for pharyngeal swabs, and 60% (6/10) for whole blood.

CONCLUSION

Overall, our data showed that the commercial ddPCR assay allowed the DNA detection of MPXV in 87.5% (35/40) of our cohort, highlighting useful technical indications for the different specimens with a potential greatest performance for skin lesions and rectal swabs.

Host immunological responses facilitate development of SARS-CoV-2 mutations in patients receiving monoclonal antibody treatments

BackgroundThe role of host immunity in emergence of evasive SARS-CoV-2 Spike mutations under therapeutic monoclonal antibody (mAb) pressure remains to be explored.MethodsIn a prospective, observational, monocentric ORCHESTRA cohort study, conducted between March 2021 and November 2022, mild-to-moderately ill COVID-19 patients (n = 204) receiving bamlanivimab, bamlanivimab/etesevimab, casirivimab/imdevimab, or sotrovimab were longitudinally studied over 28 days for viral loads, de novo Spike mutations, mAb kinetics, seroneutralization against infecting variants of concern, and T cell immunity. Additionally, a machine learning-based circulating immune-related biomarker (CIB) profile predictive of evasive Spike mutations was constructed and confirmed in an independent data set (n = 19) that included patients receiving sotrovimab or tixagevimab/cilgavimab.ResultsPatients treated with various mAbs developed evasive Spike mutations with remarkable speed and high specificity to the targeted mAb-binding sites. Immunocompromised patients receiving mAb therapy not only continued to display significantly higher viral loads, but also showed higher likelihood of developing de novo Spike mutations. Development of escape mutants also strongly correlated with neutralizing capacity of the therapeutic mAbs and T cell immunity, suggesting immune pressure as an important driver of escape mutations. Lastly, we showed that an antiinflammatory and healing-promoting host milieu facilitates Spike mutations, where 4 CIBs identified patients at high risk of developing escape mutations against therapeutic mAbs with high accuracy.ConclusionsOur data demonstrate that host-driven immune and nonimmune responses are essential for development of mutant SARS-CoV-2. These data also support point-of-care decision making in reducing the risk of mAb treatment failure and improving mitigation strategies for possible dissemination of escape SARS-CoV-2 mutants.FundingThe ORCHESTRA project/European Union's Horizon 2020 research and innovation program.

Diagnostic Accuracy of a Rapid SARS-CoV-2 Antigen Test Among People Experiencing Homelessness: A Prospective Cohort and Implementation Study

INTRODUCTION

Detection strategies in vulnerable populations such as people experiencing homelessness (PEH) need to be explored to promptly recognize severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreaks. This study investigated the diagnostic accuracy of a rapid SARS-CoV-2 Ag test in PEH during two pandemic waves compared with gold standard real-time multiplex reverse transcription polymerase chain reaction (rtRT-PCR).

METHODS

All PEH ≥ 18 years requesting residence at the available shelters in Verona, Italy, across two cold-weather emergency periods (November 2020-May 2021 and December 2021-April 2022) were prospectively screened for SARS-CoV-2 infection by means of a naso-pharyingeal swab. A lateral flow immunochromatographic assay (Biocredit^® COVID-19 Ag) was used as antigen-detecting rapid diagnostic test (Ag-RDT). The rtRT-PCR was performed with Allplex™ SARS-CoV-2 assay kit (Seegene). Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated as measures for diagnostic accuracy.

RESULTS

Overall, 503 participants were enrolled during the two intervention periods for a total of 732 paired swabs collected: 541 swabs in the first period and 191 in the second. No significant differences in demographic and infection-related characteristics were observed in tested subjects in the study periods, except for the rate of previous infection (0.8% versus 8%; p < 0.001) and vaccination (6% versus 73%; p < 0.001). The prevalence of SARS-CoV-2 in the cohort was 8% (58/732 swabs positive with rtRT-PCR). Seventeen swabs were collected from symptomatic patients (7%). Among them, the concordance between rtRT-PCR and Ag-RDT was 100%, 7 (41.2%) positive and 10 negative pairs. The overall sensitivity of Ag-RDT was 63.8% (95% CI 60.3-67.3) and specificity was 99.8% (95% CI 99.6-100). PPV and NPV were 97.5% and 96.8%, respectively. Sensitivity and specificity did not change substantially across the two periods (65.1% and 99.8% in 2020-2021 vs. 60% and 100% in 2021-2022).

CONCLUSIONS

A periodic Ag-RDT-based screening approach for PEH at point of care could guide preventive measures, including prompt isolation, without referral to hospital-based laboratories for molecular test confirmation in case of positive detection even in individuals asymptomatic for COVID-19. This could help reduce the risk of outbreaks in shelter facilities.

EPI-Net One Health reporting guideline for antimicrobial consumption and resistance surveillance data: a Delphi approach

Strategic and standardised approaches to analysis and reporting of surveillance data are essential to inform antimicrobial resistance (AMR) mitigation measures, including antibiotic policies. Targeted guidance on linking full-scale AMR and antimicrobial consumption (AMC)/antimicrobial residues (AR) surveillance data from the human, animal, and environmental sectors is currently needed. This paper describes the initiative whereby a multidisciplinary panel of experts (56 from 20 countries-52 high income, 4 upper middle or lower income), representing all three sectors, elaborated proposals for structuring and reporting full-scale AMR and AMC/AR surveillance data across the three sectors. An evidence-supported, modified Delphi approach was adopted to reach consensus among the experts for dissemination frequency, language, and overall structure of reporting; core elements and metrics for AMC/AR data; core elements and metrics for AMR data. The recommendations can support multisectoral national and regional plans on antimicrobials policy to reduce resistance rates applying a One Health approach.

Enhancing public health communication of vaccine trials: The pan-European VACCELERATE Toolkit

BACKGROUND

The pan-European VACCELERATE network aims to implement the first transnational harmonised and sustainable vaccine trial Volunteer Registry, serving as single entry-point for volunteers willing to participate in large scale vaccine clinical studies across the European region. The present work exhibits a set of harmonised vaccine trial educational and promotional tools for the general public, designed and disseminated by the pan-European VACCELERATE network.

OBJECTIVE

The main objectives of the present study are the design and creation of a standard toolkit to increase positive attitudes, and access to trustful information for better access and increased recruitment to vaccine trials for the public community. More specifically, the produced tools are focused on inclusiveness, equity, and they are targeting different population groups, including underserved ones, as potential volunteers for the VACCELERATE Volunteer Registry (elderly, migrants, children and adolescents). The promotion/education material is aligned with the main objectives of the Volunteer Registry, to increase public literacy and awareness regarding vaccine clinical research/trials and trial participation, such as informed consent and legal issues, side effects and frequently asked questions on vaccine trial design.

METHODS

The tools' development has followed the aims and principles of the VACCELERATE project, focusing on trial inclusiveness and equity and they are adjusted to the local country requirements to improve public health communication. The selection of the produced tools has been based on the cognitive theory, inclusiveness and equity of different aged and under-represented groups, and standardised material from several official trustful sources (e.g. COVAX, ECDC, EUPATI, GAVI and WHO). In addition, team of specialists from different fields (infectious diseases, vaccine research, medicine, education) edited and reviewed the subtitles and scripts for the educational videos, extended brochures, interactive cards and puzzles. Graph designers also selected the colour palette, audio settings and dubbing for the video story-tales and implementation of QR codes.

RESULTS

This study presents the first set of harmonised promotional and educational materials/tools (i.e. educational cards, educational and promotional videos, extended brochures, flyers, posters, and puzzles) for vaccine clinical research (e.g. COVID-19). The developed tools inform the public about possible benefits and disadvantages of trial participation, but also build the confidence of participants about the safety and efficacy for COVID-19 vaccines and healthcare system. The present material has been translated into several languages and meant to be freely and easily accessible to facilitate dissemination among the participating countries of the VACCELERATE network, as well as among the European and global scientific, industrial, and public community, in general.

CONCLUSIONS

The produced material could also be useful for filling knowledge gaps of healthcare personnel and providing the appropriate future patient education for vaccine trials, as well as to tackle vaccine hesitancy and parents' concerns for potential participation of children in vaccine trials.

The multi-drug resistant organisms infections decrease during the antimicrobial stewardship era in cirrhotic patients: An Italian cohort study

BACKGROUND AND PURPOSE

Bacterial infections represent a major cause of morbidity and mortality in cirrhotic patients. Our aim was to assess the incidence of bacterial infections, in particular due to multidrug-resistant organisms (MDROs) before and after the introduction of the antimicrobial stewardship program, "Stewardship Antimicrobial in VErona" (SAVE). In addition, we also analysed the liver complications and the crude mortality during the whole follow up.

METHODS

We analysed 229 cirrhotic subjects without previous hospitalization for infections enrolled at the University Verona Hospital from 2017 to 2019 and followed up until December 2021 (mean follow-up 42.7 months).

RESULTS

101 infections were recorded and 31.7% were recurrent. The most frequent were sepsis (24.7%), pneumonia (19.8%), spontaneous bacterial peritonitis (17.8%). 14.9% of infections were sustained by MDROs. Liver complications occurred more frequently in infected patients, and in case of MDROs infections with a significantly higher MELD and Child-Pugh score. In Cox regression analysis, mortality was associated with age, diabetes and bacterial infections episodes (OR 3.30, CI 95%: (1.63-6.70). Despite an increase in total infections over the past three years, a decrease in the incidence rate in MDROs infections was documented concurrently with the introduction of SAVE (IRD 28.6; 95% CI: 4.6-52.5, p = 0.02).

CONCLUSIONS

Our study confirms the burden of bacterial infections in cirrhotic patients, especially MDROs, and the strong interconnection with liver complications. The introduction of SAVE decreased MDROs infections. Cirrhotic patients require a closer clinical surveillance to identify colonized patients and avoid the horizontal spread of MDROs in this setting.

Colonisation with Extended-Spectrum Cephalosporin-Resistant Enterobacterales and Infection Risk in Surgical Patients: A Systematic Review and Meta-analysis

INTRODUCTION

Limited evidence has been reported for surgical site infections (SSIs) in patients undergoing surgery who are carriers of extended-spectrum cephalosporin-resistant Enterobacterales (ESCR-E). A systematic review and meta-analysis were conducted to evaluate the risk of postoperative infections in adult inpatients colonised with ESCR-E before surgery.

METHODS

The Medline, Embase and Cochrane databases were searched between January 2011 and April 2022, following PRISMA indications. Random effects meta-analysis was used to quantify the association between ESCR-E colonisation and infection.

RESULTS

Among the 467 articles reviewed, 9 observational studies encompassing 7219 adult patients undergoing surgery were included. The ESCR-E colonisation rate was 13.7% (95% CI 7.7-19.7). The most commonly reported surgeries included abdominal surgery (44%) and liver transplantation (LT; 33%). The SSI rate was 23.2% (95% CI 13.2-33.1). Pooled incidence risk was 0.36 (95% CI 0.22-0.50) vs 0.13 (95% CI 0.02-0.24) for any postoperative infection and 0.28 (95% CI 0.18-0.38) vs 0.17 (95% CI 0.07-0.26) for SSIs in ESCR-E carriers vs noncarriers, respectively. In ESCR-E carriers, the ESCR-E infection ratio was 7 times higher than noncarriers. Postoperative infection risk was higher in carriers versus noncarriers following LT. Sources of detected heterogeneity between studies included ESCR-E colonisation and the geographic region of origin.

CONCLUSIONS

Patients colonised with ESCR-E before surgery had increased incidence rates of post-surgical infections and SSIs compared to noncarriers. Our results suggest considering the implementation of pre-surgical screening for detecting ESCR-E colonisation status according to the type of surgery and the local epidemiology.

Efficacy and safety of baricitinib in hospitalized adults with severe or critical COVID-19 (Bari-SolidAct): a randomised, double-blind, placebo-controlled phase 3 trial

BACKGROUND

Baricitinib has shown efficacy in hospitalized patients with COVID-19, but no placebo-controlled trials have focused specifically on severe/critical COVID, including vaccinated participants.

METHODS

Bari-SolidAct is a phase-3, multicentre, randomised, double-blind, placebo-controlled trial, enrolling participants from June 3, 2021 to March 7, 2022, stopped prematurely for external evidence. Patients with severe/critical COVID-19 were randomised to Baricitinib 4 mg once daily or placebo, added to standard of care. The primary endpoint was all-cause mortality within 60 days. Participants were remotely followed to day 90 for safety and patient related outcome measures.

RESULTS

Two hundred ninety-nine patients were screened, 284 randomised, and 275 received study drug or placebo and were included in the modified intent-to-treat analyses (139 receiving baricitinib and 136 placebo). Median age was 60 (IQR 49-69) years, 77% were male and 35% had received at least one dose of SARS-CoV2 vaccine. There were 21 deaths at day 60 in each group, 15.1% in the baricitinib group and 15.4% in the placebo group (adjusted absolute difference and 95% CI - 0.1% [- 8·3 to 8·0]). In sensitivity analysis censoring observations after drug discontinuation or rescue therapy (tocilizumab/increased steroid dose), proportions of death were 5.8% versus 8.8% (- 3.2% [- 9.0 to 2.7]), respectively. There were 148 serious adverse events in 46 participants (33.1%) receiving baricitinib and 155 in 51 participants (37.5%) receiving placebo. In subgroup analyses, there was a potential interaction between vaccination status and treatment allocation on 60-day mortality. In a subsequent post hoc analysis there was a significant interaction between vaccination status and treatment allocation on the occurrence of serious adverse events, with more respiratory complications and severe infections in vaccinated participants treated with baricitinib. Vaccinated participants were on average 11 years older, with more comorbidities.

CONCLUSION

This clinical trial was prematurely stopped for external evidence and therefore underpowered to conclude on a potential survival benefit of baricitinib in severe/critical COVID-19. We observed a possible safety signal in vaccinated participants, who were older with more comorbidities. Although based on a post-hoc analysis, these findings warrant further investigation in other trials and real-world studies. Trial registration Bari-SolidAct is registered at NCT04891133 (registered May 18, 2021) and EUClinicalTrials.eu ( 2022-500385-99-00 ).

Resolving colistin resistance and heteroresistance in Enterobacter species

Species within the Enterobacter cloacae complex (ECC) include globally important nosocomial pathogens. A three-year study of ECC in Germany identified Enterobacter xiangfangensis as the most common species (65.5%) detected, a result replicated by examining a global pool of 3246 isolates. Antibiotic resistance profiling revealed widespread resistance and heteroresistance to the antibiotic colistin and detected the mobile colistin resistance (mcr)-9 gene in 19.2% of all isolates. We show that resistance and heteroresistance properties depend on the chromosomal arnBCADTEF gene cassette whose products catalyze transfer of L-Ara4N to lipid A. Using comparative genomics, mutational analysis, and quantitative lipid A profiling we demonstrate that intrinsic lipid A modification levels are genospecies-dependent and governed by allelic variations in phoPQ and mgrB, that encode a two-component sensor-activator system and specific inhibitor peptide. By generating phoPQ chimeras and combining them with mgrB alleles, we show that interactions at the pH-sensing interface of the sensory histidine kinase phoQ dictate arnBCADTEF expression levels. To minimize therapeutic failures, we developed an assay that accurately detects colistin resistance levels for any ECC isolate.