Antimicrobial resistance and antibiotic stewardship programs in the ICU: insistence and persistence in the fight against resistance. A position statement from ESICM/ESCMID/WAAAR round table on multi-drug resistance

From resistance to treatment: the ongoing struggle with Acinetobacter baumannii

Acinetobacter baumannii (A. baumannii) has become a major hospital-acquired pathogen, well-known for its rapid development of resistance to multiple antibiotics. The rising incidence of antibiotic-resistant A. baumannii presents a significant global public health challenge. Gaining a deep understanding of the mechanisms behind this resistance is essential for creating effective treatment options. This comprehensive review explores the understanding of various antibiotic resistance mechanisms in A. baumannii. It covers intrinsic resistance, acquired resistance genes, efflux pumps, changes in outer membrane permeability, alterations in drug targets, biofilm formation, and horizontal gene transfer. Additionally, the review investigates the role of mobile genetic elements and the clinical implications of antibiotic resistance in A. baumannii infections. The insights provided may inform the development of new antimicrobial agents and the design of effective infection control strategies to curb the spread of multidrug-resistant (MDR) A. baumannii strains in healthcare environments. Unlike previous reviews, this study offers a more integrative perspective by also addressing the pathogen's environmental resilience, with particular emphasis on its resistance to desiccation and the formation of robust biofilms. It further evaluates both established and emerging therapeutic strategies, thereby expanding the current understanding of A. baumannii persistence and treatment.

Antipseudomonal cephalosporins versus piperacillin/tazobactam or carbapenems for the definitive antibiotic treatment of Pseudomonas aeruginosa bacteraemia: new kids on the ICU block?

BACKGROUND

Pseudomonas aeruginosa bloodstream infections (Pa-BSIs) are still a major cause of mortality in ICUs, posing many treatment uncertainties.

METHODS

This multicentre, retrospective study analysed data from 14 Italian hospitals, including all consecutive adults developing Pa-BSI in ICU during 2021-22 and treated with antibiotics for at least 48 h. The primary aim was to identify predictors of 30 day mortality using Cox regression. Results were adjusted with inverse probability of treatment weighting (IPTW) and for immortal time bias.

RESULTS

Overall, 170 patients were included. High-risk BSI (source: lung, intra-abdominal, CNS) occurred in 118 (69%) patients, and 54 (32%) had septic shock. In 37 (22%), 73 (43%), 12 (7%) and 48 (28%) the definitive backbone therapy was piperacillin/tazobactam, carbapenems, colistin or new antipseudomonal cephalosporins (ceftolozane/tazobactam, n = 20; ceftazidime/avibactam, n = 22; cefiderocol, n = 6), respectively. Moreover, 58 (34%) received a second drug as combination therapy. The incidence of 30 day all-cause mortality was 27.6% (47 patients). By Cox regression, Charlson comorbidity index, neutropenia, septic shock and high-risk BSI were independent predictors of 30 day mortality, while previous colonization by P. aeruginosa, use of antipseudomonal cephalosporins as definitive treatment, and combination therapy were shown to be protective. However, after IPTW adjustment, only the protective effect of antipseudomonal cephalosporins was confirmed (adjusted HR = 0.27, 95% CI = 0.10-0.69), but not for combination therapy. Hence, the treatment effect was calculated: antipseudomonal cephalosporins significantly reduced mortality risk [-17% (95% CI = -4% to -30%)], while combination therapy was beneficial only in the case of septic shock [-66% (95% CI = -44% to -88%].

CONCLUSIONS

In ICU, antipseudomonal cephalosporins may be the preferred target therapy for the treatment of Pa-BSI; in addition, initial combination therapy may be protective in the case of septic shock.

Emergency medicine updates: Management of sepsis and septic shock

INTRODUCTION

Sepsis is a common condition associated with significant morbidity and mortality. Emergency physicians play a key role in the diagnosis and management of this condition.

OBJECTIVE

This paper evaluates key evidence-based updates concerning the management of sepsis and septic shock for the emergency clinician.

DISCUSSION

Sepsis is a life-threatening syndrome, and rapid diagnosis and management are essential. Antimicrobials should be administered as soon as possible, as delays are associated with increased mortality. Resuscitation targets include mean arterial pressure ≥ 65 mmHg, mental status, capillary refill time, lactate, and urine output. Intravenous fluid resuscitation plays an integral role in those who are fluid responsive. Balanced crystalloids and normal saline are both reasonable options for resuscitation. Early vasopressors should be initiated in those who are not fluid-responsive. Norepinephrine is the recommended first-line vasopressor, and if hypotension persists, vasopressin should be considered, followed by epinephrine. Administration of vasopressors through a peripheral 20-gauge or larger intravenous line is safe and effective. Steroids such as hydrocortisone and fludrocortisone should be considered in those with refractory septic shock.

CONCLUSION

An understanding of the recent updates in the literature concerning sepsis and septic shock can assist emergency clinicians and improve the care of these patients.

Integrating socioeconomic deprivation indices and electronic health record data to predict antimicrobial resistance

We developed machine learning models to predict the presence of AMR organisms in blood cultures obtained at the first patient encounter, offering a new and inspiring direction for antimicrobial resistance management. Three supervised machine learning classifiers were used: penalized logistic regression, random forest, and XGBoost, which were used to classify five AMR organisms: ESBL, CRE, AmpC, MRSA, and VRE. The random forest and XGBoost models performed best, with AUC-ROC values of 0.70 and 92.9% negative predictive value, respectively. The multi-class random forest model's AUC-ROC values ranged from 0.80-0.95. Our models highlight how the combination of ADI and SVI increased the predictive power. This approach could reduce costs and mitigate the global public health threat posed by antibiotic-resistant infections. Machine learning techniques can predict antimicrobial-resistant infections in suspected cultures using patient data from EHRs, enabling clinicians to make targeted prescribing decisions and mitigate resistance development.

Unpacking the sepsis controversy

Despite its many definitions and revisions, consensus statements and clinical guidelines, the term 'sepsis' continues to be referred to as a discrete clinical entity that is often claimed to be a direct cause of mortality. The assertion that sepsis can be defined as a 'life-threatening organ dysfunction caused by a dysregulated host response to infection,' has led to a field dominated by failed clinical trials informed by host-centered, pathogen-agnostic, animal experiments in which animal models do not recapitulate the clinical condition. The observations from the National Health Service from England that claim that 77.5% of sepsis deaths occur in those aged 75 years or older and those from the USA indicating that most patients dying of sepsis have also been diagnosed with 'hospice qualifying conditions,' seem to refute the assertion that sepsis is caused by, rather than associated with, a 'dysregulated host response.' This piece challenges the current conceptual framework that forms the basis of the sepsis definition. Here we posit that as a result of both its definition and the use of inappropriate animal models, ineffective clinical treatments continue to be pursued in this field.

Unveiling antimicrobial stewardship competence among Italian nurses: results from a nationwide survey

BACKGROUND

The development of nursing competencies in antimicrobial stewardship (AMS) is influenced by a two-dimensional model, encompassing both internal and environmental factors. In the context of Italian clinical nursing, this study aims to assess and measure these aspects.

METHODS

Employing a cross-sectional online survey design, nurses from various clinical specialties in Italy were involved. The questionnaire assessed individual variables, knowledge, attitudes, practices, as well as structural and process-related variables influencing AMS. Statistical analyses were performed, encompassing descriptive statistics, Pearson correlation, and multiple linear regression.

RESULTS

A total of 1,651 nurses aswered the survey, with a participation rate of 50.8%. The participant demographic revealed that 77% were female, and they had an average of 15 years of experience. Workplace and regional factors were found to significantly impact both AMS practices and attitudes. Surgical nurses reported higher practices scores (β = 0.467, P <.01), while critical care nurses scored lower (β= -0.398, P <.01). Regarding perceptions of structure, workplace characteristics significantly influenced nurses' scores, indicating lower perceptions among surgical nurses compared to their medical counterparts (β= -0.315, P <.01).

CONCLUSIONS

The study reveals the intricate interplay between internal and external factors that impact nurses' AMS competence. This underscores the urgent need for targeted interventions and education initiatives to enhance nurses' AMS competencies. Specifically, addressing variations in settings and nurses' behaviours becomes imperative for achieving improved patient outcomes.

Antimicrobial infusion practices within intensive care units: Carbapenem infusion preparation and administration process errors

OBJECTIVE

To describe nurse preparation and administration of intermittent carbapenem infusions.

RESEARCH METHODOLOGY/DESIGN

This observational study documented the carbapenem infusion process to adult patients in three general intensive care units.

MAIN OUTCOME MEASURES

Timing and duration of infusions were observed. Volumetric analysis of infusion items was conducted to determine loss of reconstituted carbapenem during preparation and administration phases.

RESULTS

Carbapenem infusions (n = 223) administered to twenty adult patients were observed. Infusion duration guidance was variable, with two ICUs following current literature recommendations, and one ICU referring to medication package insert information. Within these parameters, only 60 % of infusions complied with infusion duration. Non-compliance with planned time of administration impacted on desired dosing intervals. Incomplete delivery of intended dose was found during: sub-optimal reconstitution of vials, incorrect number of vials reconstituted, failure to administer a dose (missed dose), and discarding antibiotic residue in infusion items. Volumetric analysis of infusion items showed mean dose losses of 4.9 % and 1.2 % in discarded vials and syringes. Mean drug losses of 6.3 % and 30.8 % occurred in discarded infusion bags and infusion lines respectively. No flushing guidance or practice was observed.

CONCLUSION

Incorrect nurse administration of antibiotics resulted in varying durations of infusions and the non-delivery of prescribed dose. Under-dosing has the potential to contribute to selection pressure for bacterial antibiotic resistance. The increasing frequency of intravenous delivery of antimicrobial agents through infusions requires an understanding of the required duration of administration and how to manage residual drug remaining in the intravenous line once the infusion is completed.

IMPLICATIONS FOR CLINICAL PRACTICE

Flushing of administration lines is not common practice following intermittent antimicrobial infusions. Although there are multi-factorial risk factors for antimicrobial resistance in the critical care arena, nurse infusion practice must ensure that patients receive intended antimicrobial treatment. Attention must be given to the potential for antimicrobial resistance from environmental contamination with the disposal of infusion items containing undelivered antimicrobial medication.

Risk factors for colonisation by Multidrug-Resistant bacteria in critical care units

INTRODUCTION

Antimicrobial resistance is a major public health challenge recognised by the WHO as an urgent global healthcare concern. Patients in Intensive Care Units (ICUs) are particularly prone to colonisation and/or infection by multidrug-resistant organisms (MDROs).

OBJECTIVES

Delineate the epidemiological characteristics and risk factors for MDROs colonisation in mixed ICUs and Resuscitation Units by focusing on initial and nosocomial colonisation.

MATERIAL AND METHODS

A descriptive observational study with analytical elements. It uses the Zero-Resistance register from the Preventive Medicine Service of the Albacete General University Hospital (Spain) from April 2016 to December 2021. It identifies the risk factors for MDROs colonisation.

RESULTS

Of 7,541 cases, 61.0 % with initial colonisation had risk factors for MDROs versus 34.0 % not colonised upon hospitalisation (p < 0.001). Significant risk factors for initial colonisation included hospitalisation for ≥ 5 days within the last 3 months, prior MDROs colonisation/infection and institutionalization. No significant risk factor differences were found for nosocomial colonisation. An association between longer ICU stays and nosocomial colonisation (p < 0.001) was noted.

CONCLUSIONS

Significant risk factors for initial MDROs colonisation were hospitalisation for ≥ 5 days in the last 3 months, prior MDROs colonisation/infection and institutionalisation. Longer ICU stays increased the nosocomial colonisation risk.

IMPLICATIONS FOR CLINICAL PRACTICE

This study underscores the importance to early identify and manage patients at risk for MDROs colonisation in ICUs. By recognising factors (i.e. previous hospitalisations, existing colonisation or infection, impact of prolonged ICU stay), healthcare providers can implement targeted strategies to mitigate the spread of MDROs; e.g. enhanced surveillance, stringent infection control measures and judicious antibiotics use. Our findings highlight the need for a comprehensive approach to manage antimicrobial resistance in critical care settings to ultimately improve patient outcomes and reduce MDROs burden in hospitals.

Antimicrobial Macrocycles - Synthesis, Characterization, and Activity Comparison with Their Linear Polycationic Analogues

One of the promising candidates for new antimicrobial agents is membrane-lytic compounds that kill microbes through cell membrane permeabilization, such as antimicrobial peptides (AMPs) and their synthetic mimics (SMAMPs). Although SMAMPs have been under investigation for nearly 30 years, a few challenges must be addressed before they can reach clinical use. In this work, a step-growth polymerization leading to already-known highly antimicrobial ionenes was redirected toward the formation of macrocyclic quaternary ammonium salts (MQAs) employing a high dilution principle. Antimicrobial assays and cytotoxicity studies revealed the high antimicrobial activity of MQAs and better selectivity than their polymeric analogues. Therefore, MQAs seem to be a new class of promising antibacterial agents. Additionally, membrane-lytic experiments using large unilamellar liposomes (LUVs) and whole cells revealed significant differences between MQAs and ionenes in their ability to adsorb onto the surface of LUVs and microbes as well as their ability to permeate the lipid bilayer.

Implementing an Antimicrobial Stewardship Program and Complete Screening in an Intensive Care Unit in Relation to the Overall Clinical Outcome of Patients

BACKGROUND

The high prevalence of resistant microorganisms indicates a multidisciplinary approach, which will ensure efficiency and balance between resistance therapy of choice and the implementation of an antimicrobial stewardship (AMS) program in intensive unit care (ICU).

OBJECTIVES

The objectives are based on the assessment of AMS in a cardiac surgical intensive care unit (CICU), by determination with the reduction of: inotropic support, length of antibiotic treatment, and need for renal replacement therapy (RRT).

MATERIAL AND METHODS

The research is a retrospective, group comparative, analytical cross-sectional study, in the period from 2020-2023, within the Cardiosurgery department, at Acibadem Sistina. 1277 patients participated in the research, divided into two groups: group 1 (2020-2021) and group 2 (2022-2023). Primary endpoints investigated: inotropic support, need for RRT and length of antibiotic treatment. Secondary endpoints investigated: optimization of antibiotic therapeutic regimen and clinical outcome assessment of patients (survival).

RESULTS

The inotropic support during 24, 48 and 72 h was statistically significantly lower in group 2. A statistically significant shorter length of time for antibiotic treatment was determined in patients in group 2 (p=0.000), as well as a lower value of the need for RRT. A statistically significant difference in time to event (fatal outcome) was determined between the two groups (p=0.000). A significant difference (p=0.000) was determined in the prescription and optimization of the therapeutic regimen.

CONCLUSION

Integrating AMS, initial comprehensive microbiological screening and application of biomarkers in the CICU, established appropriately, will result in improved overall clinical outcome for patients.

Longitudinal genomic surveillance of a UK intensive care unit shows a lack of patient colonisation by multi-drug-resistant Gram-negative bacterial pathogens

Vulnerable patients in an intensive care unit (ICU) setting are at high risk of infection from bacteria including gut-colonising Escherichia coli and Klebsiella species. Complex ICU procedures often depend on successful antimicrobial treatment, underscoring the importance of understanding the extent of patient colonisation by multi-drug-resistant organisms (MDROs) in large UK ICUs. Previous work on ICUs globally uncovered high rates of colonisation by transmission of MDROs, but the situation in UK ICUs is less understood. Here, we investigated the diversity and antibiotic resistance gene (ARG) carriage of bacteria present in one of the largest UK ICUs at the Queen Elizabeth Hospital Birmingham (QEHB), focusing primarily on E. coli as both a widespread commensal and a globally disseminated multi-drug-resistant pathogen. Samples were taken during highly restrictive coronavirus disease 2019 (COVID-19) control measures from May to December 2021. Whole-genome and metagenomic sequencing were used to detect and report strain-level colonisation of patients, focusing on E. coli sequence types (STs), their colonisation dynamics and antimicrobial resistance gene carriage. We found a lack of multi-drug resistance (MDR) in the QEHB. Only one carbapenemase-producing organism was isolated, a Citrobacter carrying bla KPC-2. There was no evidence supporting the spread of this strain, and there was little evidence overall of nosocomial acquisition or circulation of colonising E. coli. Whilst 22 different E. coli STs were identified, only 1 strain of the pandemic ST131 lineage was isolated. This ST131 strain was non-MDR and was found to be a clade A strain, associated with low levels of antibiotic resistance. Overall, the QEHB ICU had very low levels of pandemic or MDR strains, a result that may be influenced in part by the strict COVID-19 control measures in place at the time. Employing some of these infection prevention and control measures where reasonable in all ICUs might therefore assist in maintaining low levels of nosocomial MDR.

Reduced mortality with antimicrobial stewardship guided by BioFire FilmArray Blood Culture Identification 2 panel in critically ill patients with bloodstream infection: A retrospective propensity score-matched study

OBJECTIVES

To investigate whether using the BioFire® FilmArray® Blood Culture Identification 2 panel (BCID2) leads to timely antimicrobial therapy and improves patient outcomes in critically ill patients with bloodstream infections (BSIs).

METHODS

This retrospective observational study included patients with BSIs admitted to the intensive care unit from July 1, 2021, to August 31, 2023. Patients were divided into groups receiving appropriate or inappropriate antimicrobial therapy. Those receiving inappropriate therapy underwent adjustments using standard-of-care (SOC) testing or BCID2. Propensity score matching (PSM) was performed on the original cohort (Model 1) and a time-window bias-adjusted cohort (Model 2). Clinical impact of BCID2-guided antimicrobial adjustment was analysed in both models.

RESULTS

A total of 181 patients received inappropriate antimicrobial therapy, with 33 undergoing BCID2 testing and 148 undergoing SOC testing. Following PSM and time-window bias adjustment, 66 patients were analysed in Model 1 and 46 patients in Model 2. BCID2 significantly reduced the median time to appropriate antimicrobial therapy (40.8 vs. 74.0 h in Model 1; 42.8 vs. 68.9 h in Model 2) and the day-28 mortality rate (27.8% vs. 77.1%, P < 0.001 in Model 1; 23.5% vs. 58.6%, P = 0.021 in Model 2). In multivariate regression analysis, BCID2-guided antimicrobial adjustment was an independent prognostic factor for day-28 mortality (adjusted odds ratio [aOR] 0.07 in Model 1 and aOR 0.12 in Model 2).

CONCLUSION

BCID2-guided antimicrobial stewardship was associated with a shorter time to appropriate antimicrobial therapy and reduced day-28 mortality in critically ill patients with BSIs receiving inappropriate antimicrobial therapy.

The real-world impact of the BioFire FilmArray blood culture identification 2 panel on antimicrobial stewardship among patients with bloodstream infections in intensive care units with a high burden of drug-resistant pathogens

BACKGROUND

The increasing prevalence of drug-resistant pathogens leads to delays in adequate antimicrobial treatment in intensive care units (ICU). The real-world influence of the BioFire FilmArray Blood Culture Identification 2 (BCID2) panel on pathogen identification, diagnostic concordance with conventional culture methods, and antimicrobial stewardship in the ICU remains unexplored.

METHODS

This retrospective observational study, conducted from July 2021 to August 2023, involved adult ICU patients with positive blood cultures who underwent BCID2 testing. The concordance between BCID2 and conventional culture results was examined, and its impact on antimicrobial stewardship was assessed through a comprehensive retrospective review of patient records by intensivists.

RESULTS

A total of 129 blood specimens from 113 patients were analysed. Among these patients, a high proportion of drug-resistant strains were noted, including carbapenem-resistant Klebsiella pneumoniae (CRKP) (57.1%), carbapenem-resistant Acinetobacter calcoaceticus-baumannii complex (100%), methicillin-resistant Staphylococcus aureus (MRSA) (70%), and vancomycin-resistant Enterococcus faecium (VRE) (100%). The time from blood culture collection to obtaining BCID2 results was significantly shorter than conventional culture (46.2 h vs. 86.9 h, p < 0.001). BCID2 demonstrated 100% concordance in genotype-phenotype correlation in antimicrobial resistance (AMR) for CRKP, carbapenem-resistant Escherichia coli, MRSA, and VRE. A total of 40.5% of patients received inadequate empirical antimicrobial treatment. The antimicrobial regimen was adjusted or confirmed in 55.4% of patients following the BCID2 results.

CONCLUSIONS

In the context of a high burden of drug-resistant pathogens, BCID2 demonstrated rapid pathogen and AMR detection, with a noticeable impact on antimicrobial stewardship in BSI in the ICU.

Immunosuppression at ICU admission is not associated with a higher incidence of ICU-acquired bacterial bloodstream infections: the COCONUT study

BACKGROUND

Immunosuppression at intensive care unit (ICU) admission has been associated with a higher incidence of ICU-acquired infections, some of them related to opportunistic pathogens. However, the association of immunosuppression with the incidence, microbiology and outcomes of ICU-acquired bacterial bloodstream infections (BSI) has not been thoroughly investigated.

METHODS

Retrospective single-centered cohort study in France. All adult patients hospitalized in the ICU of Lille University-affiliated hospital for > 48 h between January 1st and December 31st, 2020, were included, regardless of their immune status. Immunosuppression was defined as active cancer or hematologic malignancy, neutropenia, hematopoietic stem cell and solid organ transplants, use of steroids or immunosuppressive drugs, human immunodeficiency virus infection and genetic immune deficiency. The primary objective was to compare the 28-day cumulative incidence of ICU-acquired bacterial BSI between immunocompromised and non-immunocompromised patients. Secondary objectives were to assess the microbiology and outcomes of ICU-acquired bacterial BSI in the two groups.

RESULTS

A total of 1313 patients (66.9% males, median age 62 years) were included. Among them, 271 (20.6%) were immunocompromised at ICU admission. Severity scores at admission, the use of invasive devices and antibiotic exposure during ICU stay were comparable between groups. Both prior to and after adjustment for pre-specified baseline confounders, the 28-day cumulative incidence of ICU-acquired bacterial BSI was not statistically different between immunocompromised and non-immunocompromised patients. The distribution of bacteria was comparable between groups, with a majority of Gram-negative bacilli (~ 64.1%). The proportion of multidrug-resistant bacteria was also similar between groups. Occurrence of ICU-acquired bacterial BSI was associated with a longer ICU length-of-stay and a longer duration of invasive mechanical ventilation, with no significant association with mortality. Immune status did not modify the association between occurrence of ICU-acquired bacterial BSI and these outcomes.

CONCLUSION

The 28-day cumulative incidence of ICU-acquired bacterial BSI was not statistically different between patients with and without immunosuppression at ICU admission.

Gram-Negative Bloodstream Infections in Healthcare: The Relationship Between Antibiotic Resistance, Mortality, and Novel Serological Biomarker

BACKGROUND

Bloodstream infections caused by Gram-negative bacteria are highly mortal. In this study, we aimed to investigate the relationship between antimicrobial resistance profile and novel serological biomarkers and mortality in bloodstream infections (BSIs) caused by Gram-negative bacteria in intensive care units (ICUs).

METHODS

366 Patients diagnosed with healthcare-associated Gram-negative bloodstream infection in the ICUs of our hospital between February 2015 and December 2021 were included in the study. Demographic variables (age, gender, comorbidities), causative microorganisms and antimicrobial susceptibilities, time to first positive blood culture after hospitalization, length of stay in hospital, surgical procedures, laboratory data (hemograms, C-reactive protein (CRP) levels, albumin), and survival data were collected. Novel serological biomarkers were calculated.

RESULTS

Mortality in Gram-negative bloodstream infection was found to be associated with age and novel serological biomarkers, but not with carbapenems and colistin minimum inhibitory concentration (MIC) values. Mortality rates increased with age (p˂0.001). Patients who died had higher C-reactive protein/albumin ratio (CAR) (p<0.001) and neutrophil/lymphocyte ratio (NLR) (p=0.009) and lower prognostic nutritional index (PNI) (p<0.001).

CONCLUSION

The study emphasizes that resistance to colistin and carbapenems is not associated with mortality in BSIs caused by Gram-negative bacteria. Novel serological biomarkers may be useful in predicting mortality. These results support the need for further studies to elucidate the true impact of infections caused by resistant bacteria.

Septic shock and biliary sepsis: 90-day mortality and associated risk factors

BACKGROUND

Biliary sepsis is common in patients with digestive cancer. Recommendations call for antibiotic de-escalation (ADE) as a strategy for antibiotic treatment of sepsis or septic shock. The aim of this study was to identify factors influencing 90-day mortality and to evaluate the impact of ADE.

METHODS

This retrospective study was conducted between November 2008 and December 2019 in a referral cancer center. Adults with biliary sepsis or septic shock admitted to the ICU were included. Variables associated with 90-day mortality were identified using univariate and multivariate Cox proportional hazards models.

RESULTS

122 patients were included. The 90-day mortality was 30.3% (n = 37). After multivariate analysis, the factors independently associated 90-day mortality were metastatic stage (p = 0.004), biliary tract tumour compression (p = 0.001), multi drug resistant (MDR) bacteria carriage on intensive care unit (ICU)admission (p = 0.048), serum lactate on ICU admission (p < 0.001), the use of extra-renal replacement (p = 0.008), factor V < 50% (p = 0.009) and performance status (ECOG-PS) > 2 (p < 0.001). ADE of the pivotal antibiotic (p = 0.041) and recent cancer surgery (p < 0.001) appeared to be associated with survival.

CONCLUSION

The 90-day mortality of biliary sepsis seems to be favourable. The 90-day mortality is associated with organ dysfunctions, but also with ECOG-PS, cancer stage, MDR bacteria colonisation. ADE seems to be safe.

Antimicrobial Stewardship in the Hospital Setting: A Narrative Review

The increasing global threat of antibiotic resistance, which has resulted in countless fatalities due to untreatable infections, underscores the urgent need for a strategic action plan. The acknowledgment that humanity is perilously approaching the "End of the Miracle Drugs" due to the unjustifiable overuse and misuse of antibiotics has prompted a critical reassessment of their usage. In response, numerous relevant medical societies have initiated a concerted effort to combat resistance by implementing antibiotic stewardship programs within healthcare institutions, grounded in evidence-based guidelines and designed to guide antibiotic utilization. Crucial to this initiative is the establishment of multidisciplinary teams within each hospital, led by a dedicated Infectious Diseases physician. This team includes clinical pharmacists, clinical microbiologists, hospital epidemiologists, infection control experts, and specialized nurses who receive intensive training in the field. These teams have evidence-supported strategies aiming to mitigate resistance, such as conducting prospective audits and providing feedback, including the innovative 'Handshake Stewardship' approach, implementing formulary restrictions and preauthorization protocols, disseminating educational materials, promoting antibiotic de-escalation practices, employing rapid diagnostic techniques, and enhancing infection prevention and control measures. While initial outcomes have demonstrated success in reducing resistance rates, ongoing research is imperative to explore novel stewardship interventions.

Clinical characteristics and prognosis of pneumonia-related bloodstream infections in the intensive care unit: a single-center retrospective study

Background

Bloodstream infections (BSI) are one of the most severe healthcare-associated infections in intensive care units (ICU). However, there are few studies on pneumonia-related BSI (PRBSI) in the ICU. This study aimed to investigate the clinical and prognostic characteristics of patients with PRBSI in the ICU and to provide a clinical basis for early clinical identification.

Methods

We retrospectively collected data from patients with bacterial BSI in a single-center ICU between January 1, 2017, and August 31, 2020. Clinical diagnosis combined with whole-genome sequencing (WGS) was used to clarify the diagnosis of PRBSI, and patients with PRBSI and non-PRBSI were analyzed for clinical features, prognosis, imaging presentation, and distribution of pathogenic microorganisms.

Results

Of the 2,240 patients admitted to the MICU, 120 with bacterial BSI were included in this study. Thirty-two (26.7%) patients were identified as having PRBSI based on the clinical diagnosis combined with WGS. Compared to patients without PRBSI, those with PRBSI had higher 28-day mortality (81.3 vs.51.1%, p = 0.003), a higher total mortality rate (93.8 vs. 64.8%, p = 0.002), longer duration of invasive mechanical ventilation (median 16 vs. 6 days, p = 0.037), and prolonged duration of ICU stay (median 21 vs. 10 days, p = 0.004). There were no differences in other baseline data between the two groups, but patients with PRBSI had extensive consolidation on chest radiographs and significantly higher Radiographic Assessment of Lung Edema scores (mean 35 vs. 24, p < 0.001). The most common causative organisms isolated in the PRBSI group were gram-negative bacteria (n = 31, 96.9%), with carbapenem-resistant gram-negative bacteria accounting for 68.8% (n = 22) and multidrug-resistant bacteria accounting for 81.3% (n = 26).

Conclusion

Pneumonia-related BSI is an important component of ICU-BSI and has a poor prognosis. Compared to non-PRBSI, patients with PRBSI do not have typical clinical features but have more severe lung consolidation lesions, and should be alerted to the possibility of their occurrence when combined with pulmonary gram-negative bacterial infections, especially carbapenem-resistant bacteria. Further multicenter, large-sample studies are needed to identify the risk factors for the development of PRBSI and prevention and treatment strategies.

Active Surveillance of Antimicrobial Resistance and Carbapenemase-Encoding Genes According to Sites of Care and Age Groups in Mexico: Results from the INVIFAR Network

We analyzed the antimicrobial resistance (AMR) data of 6519 clinical isolates of Escherichia coli (n = 3985), Klebsiella pneumoniae (n = 775), Acinetobacter baumannii (n = 163), Pseudomonas aeruginosa (n = 781), Enterococcus faecium (n = 124), and Staphylococcus aureus (n = 691) from 43 centers in Mexico. AMR assays were performed using commercial microdilution systems (37/43) and the disk diffusion susceptibility method (6/43). The presence of carbapenemase-encoding genes was assessed using PCR. Data from centers regarding site of care, patient age, and clinical specimen were collected. According to the site of care, the highest AMR was observed in E. coli, K. pneumoniae, and P. aeruginosa isolates from ICU patients. In contrast, in A. baumannii, higher AMR was observed in isolates from hospitalized non-ICU patients. According to age group, the highest AMR was observed in the ≥60 years age group for E. coli, E. faecium, and S. aureus, and in the 19-59 years age group for A. baumannii and P. aeruginosa. According to clinical specimen type, a higher AMR was observed in E. coli, K. pneumoniae, and P. aeruginosa isolates from blood specimens. The most frequently detected carbapenemase-encoding gene in E. coli was blaNDM (84%).

Nursing experiences in antimicrobial optimisation in the intensive care unit: A convergent analysis of a national survey

BACKGROUND

Recent evidence highlights the need for an interdisciplinary approach to antimicrobial stewardship (AMS). Nursing involvement in optimising antimicrobials in the intensive care unit (ICU) remains understudied.

OBJECTIVE

The objective of this study was to explore nurses' perceptions and experiences of antimicrobial optimisation or stewardship in ICUs in Australia.

METHODS

An anonymous web-based survey was deployed nationally in early 2021 through two ICU nursing networks. Associations between survey responses were analysed descriptively and by using nonparametric tests (with statistical significance established at p ≤ 0.05). Free-text survey responses underwent qualitative thematic analysis. Interpretation and reporting of quantitative and qualitative data were integrated.

RESULTS

A total of 226 ICU nurses completed the survey. The majority (197/226; 87%) responded that lack of education limits engagement in AMS. Only 13% (30/226) reported the presence of AMS education and training for nurses in their ICUs. Only about half (108/226; 48%) of the nurses were confident to question prescribers when they considered that the antimicrobial prescribed was unnecessary, with nurses in senior roles more likely to do so than nurses providing bedside care (p < 0.05). Gaps in education (including unfamiliarity with AMS roles), noninclusive antimicrobial discussions, moral distress, and potential workload burden were seen as potential barriers/challenges to engagement.

CONCLUSION

The multifactorial barriers identified that inhibit nurses from performing AMS tasks could be addressed by strengthening interprofessional education at all levels and by applying practical AMS interventions that are inclusive for nursing participation. A purposeful culture change that fosters psychological safety and collaborative practice is paramount to supporting nurses in these roles.

Shortening identification times: comparative observational study of three early blood culture testing protocols

Background

While early appropriate antibiotic therapy is a proven means of limiting the progression of infections, especially bacteremia, empirical antibiotic therapy in sepsis is ineffective up to 30%. The aim of this study was to compare early blood culture testing protocols in terms of their ability to shorten the delay between blood sampling and appropriate antibiotic therapy.

Methods

In this french observational study, we compared three blood culture testing protocols. Positive blood cultures were tested using either GenMark ePlex panels (multiplex PCR period), a combination of MRSA/SA PCR, β-Lacta and oxidase tests (multitest period), or conventional identification and susceptibility tests only (reference period). Conventional identification and susceptibility tests were performed in parallel for all samples, as the gold standard.

Results

Among the 270 patients with positive blood cultures included, early and conventional results were in good agreement, especially for the multitest period. The delay between a blood culture positivity and initial results was 3.8 (2.9-6.9) h in the multiplex PCR period, 2.6 (1.3-4.5) h in the multitest period and 3.7 (1.8-8.2) h in the reference period (p<0.01). Antibiotic therapy was initiated or adjusted in 68 patients based on early analysis results. The proportion of patients receiving appropriate antibiotic therapy within 48 h of blood sampling was higher in the multiplex PCR and multitest periods, (respectively 90% and 88%) than in the reference period (71%).

Conclusion

These results suggest rapid bacterial identification and antibiotic resistance tests are feasible, efficient and can expedite appropriate antibiotic therapy.

Mortality due to Multidrug-Resistant Gram-Negative Bacteremia in an Endemic Region: No Better than a Toss of a Coin

The incidence of multidrug-resistant (MDR) bloodstream infections (BSIs) is associated with high morbidity and mortality. Little evidence exists regarding the epidemiology of BSIs and the use of appropriate empirical antimicrobial therapy in endemic regions. Novel diagnostic tests (RDTs) may facilitate and improve patient management. Data were assessed from patients with MDR Gram-negative bacteremia at a university tertiary hospital over a 12-month period. In total, 157 episodes of MDR Gram-negative BSI were included in the study. The overall mortality rate was 50.3%. Rapid molecular diagnostic tests were used in 94% of BSI episodes. In univariate analysis, age (OR 1.05 (95% CI 1.03, 1.08) p < 0.001), Charlson Comorbidity Index (OR 1.51 (95% CI 1.25, 1.83) p < 0.001), procalcitonin ≥ 1(OR 3.67 (CI 95% 1.73, 7.79) p < 0.001), and monotherapy with tigecycline (OR 3.64 (95% CI 1.13, 11.73) p = 0.030) were the only factors associated with increased overall mortality. Surprisingly, time to appropriate antimicrobial treatment had no impact on mortality. MDR pathogen isolation, other than Klebsiella pneumoniae and Acinetobacter baumanii, was associated with decreased mortality (OR 0.35 (95% CI 0.16, 0.79) p = 0.011). In multivariate analysis, the only significant factor for mortality was procalcitonin ≥ 1 (OR 2.84 (95% CI 1.13, 7.11) p = 0.025). In conclusion, in an endemic area, mortality rates in MDR BSI remain notable. High procalcitonin was the only variable that predicted death. The use of rapid diagnostics did not improve mortality rate.

Antibiotic stewardship implementation at the largest solid organ transplantation center in Asia: a retrospective cohort study

BACKGROUND

Using Antimicrobial stewardship programs (ASP) to monitor the use of antibiotics can lead to improved antibiotic use and reduced costs.

METHODS

This retrospective cohort study was done at Shiraz Organ Transplant Center, the largest transplant center in Asia. Antimicrobial use, cost, clinical outcomes, and antibiotic resistance pattern were evaluated before and after ASP.

RESULTS

This study included 2791 patients, 1154 of whom were related to the time before ASP and 1637 to the time after ASP. During the period of the research, a total of 4051 interventions were done. The use of all classes of antibiotics was significantly reduced by ASP, with 329 DDD/100PD before the intervention compared to 201 DDD/100PD after it (p = 0.04). In addition, the overall cost of antibiotics purchased was much lower after the ASP measures were implemented ($43.10 per PD) than before implementation of the ASP measures ($60.60 per PD) (p = 0.03). After the implementation of ASP, the number of MDR isolates was significantly reduced.

CONCLUSION

The results of our study showed that the implementation of ASP significantly reduced the number and costs of antibiotics and also the number of resistant pathogens, but did not affect the patients' length of stay.

Parallel Dysregulated Immune Response in Severe Forms of COVID-19 and Bacterial Sepsis via Single-Cell Transcriptome Sequencing

Critically ill COVID-19 patients start developing single respiratory organ failure that often evolves into multiorgan failure. Understanding the immune mechanisms in severe forms of an infectious disease (either critical COVID-19 or bacterial septic shock) would help to achieve a better understanding of the patient’s clinical trajectories and the success of potential therapies. We hypothesized that a dysregulated immune response manifested by the abnormal activation of innate and adaptive immunity might be present depending on the severity of the clinical presentation in both COVID-19 and bacterial sepsis. We found that critically ill COVID-19 patients demonstrated a different clinical endotype that resulted in an inflammatory dysregulation in mild forms of the disease. Mild cases (COVID-19 and bacterial non severe sepsis) showed significant differences in the expression levels of CD8 naïve T cells, CD4 naïve T cells, and CD4 memory T cells. On the other hand, in the severe forms of infection (critical COVID-19 and bacterial septic shock), patients shared immune patterns with upregulated single-cell transcriptome sequencing at the following levels: B cells, monocyte classical, CD4 and CD8 naïve T cells, and natural killers. In conclusion, we identified significant gene expression differences according to the etiology of the infection (COVID-19 or bacterial sepsis) in the mild forms; however, in the severe forms (critical COVID-19 and bacterial septic shock), patients tended to share some of the same immune profiles related to adaptive and innate immune response. Severe forms of the infections were similar independent of the etiology. Our findings might promote the implementation of co-adjuvant therapies and interventions to avoid the development of severe forms of disease that are associated with high mortality rates worldwide.

Antimicrobial Stewardship for Ventilator Associated Pneumonia in Intensive Care (the ASPIC trial): study protocol for a randomised controlled trial

INTRODUCTION

Ventilator-associated pneumonia (VAP) remains the leading cause of infections treated in the intensive care units (ICU). In a personalised care approach, we hypothesise that the duration of treatment of VAP can be reduced in function of the response to treatment.

METHODS AND ANALYSIS

The Antimicrobial Stewardship for Ventilator-Associated Pneumonia in Intensive Care (ASPIC) trial is a pragmatic national multicentre, phase III, non-inferiority, comparative randomised (1:1) single-blinded clinical trial. Five hundred and ninety adult patients hospitalised in 24 French ICU with a microbiologically confirmed first episode of VAP that received appropriate empirical antibiotic therapy will be included. They will be randomly allocated to standard management with duration of appropriate antibiotic fixed for 7 days according to international guidelines or antimicrobial stewardship based on daily clinical assessment of clinical cure. The assessment of clinical cure will be repeated daily until at least three criteria of clinical cure are met, allowing the discontinuation of antibiotic therapy in experimental group. The primary endpoint is a composite endpoint combining of all-cause mortality measured at day 28, treatment failure or new episode of microbiologically confirmed VAP until day 28.The aim of the study is to demonstrate that a strategy to reduce the duration of antibiotic therapy for VAP based on clinical assessment is safe could lead to changes in practice as part of a personalised therapeutic approach, by reducing exposure to antibiotics and their side effects.

ETHICS AND DISSEMINATION

The ASPIC trial has been approved by the French regulatory agency (Agence Nationale de Sécurité du Médicament et des Produits de Santé, ANSM; EUDRACT number 2021-002197-78, 19 August 2021) and an independent ethics committee the Comité de Protection des Personnes Ile-de-France III (CNRIPH : 21.03.25.60729, 10 October 2021) for the study protocol (version ASPIC-1.3; 03 September 2021) for all study centres. Participant recruitment is scheduled to begin in 2022. Results will be published in international peer-reviewed medical journals.

TRIAL REGISTRATION NUMBER

NCT05124977.

Impact of reduced antibiotic treatment duration on antimicrobial resistance in critically ill patients in the randomized controlled SAPS-trial

Background

In the previously reported SAPS trial (https://clinicaltrials.gov/ct2/show/NCT01139489), procalcitonin-guidance safely reduced the duration of antibiotic treatment in critically ill patients. We assessed the impact of shorter antibiotic treatment on antimicrobial resistance development in SAPS patients.

Materials and methods

Cultures were assessed for the presence of multi-drug resistant (MDR) or highly resistant organisms (HRMO) and compared between PCT-guided and control patients. Baseline isolates from 30 days before to 5 days after randomization were compared with those from 5 to 30 days post-randomization. The primary endpoint was the incidence of new MDR/HRMO positive patients.

Results

In total, 8,113 cultures with 96,515 antibiotic test results were evaluated for 439 and 482 patients randomized to the PCT and control groups, respectively. Disease severity at admission was similar for both groups. Median (IQR) durations of the first course of antibiotics were 6 days (4-10) and 7 days (5-11), respectively (p = 0.0001). Antibiotic-free days were 7 days (IQR 0-14) and 6 days (0-13; p = 0.05). Of all isolates assessed, 13% were MDR/HRMO positive and at baseline 186 (20%) patients were MDR/HMRO-positive. The incidence of new MDR/HRMO was 39 (8.9%) and 45 (9.3%) in PCT and control patients, respectively (p = 0.82). The time courses for MDR/HRMO development were also similar for both groups (p = 0.33).

Conclusions

In the 921 randomized patients studied, the small but statistically significant reduction in antibiotic treatment in the PCT-group did not translate into a detectable change in antimicrobial resistance. Studies with larger differences in antibiotic treatment duration, larger study populations or populations with higher MDR/HRMO incidences might detect such differences.

Epidemiology and outcomes of hospital-acquired bloodstream infections in intensive care unit patients: the EUROBACT-2 international cohort study

PURPOSE

In the critically ill, hospital-acquired bloodstream infections (HA-BSI) are associated with significant mortality. Granular data are required for optimizing management, and developing guidelines and clinical trials.

METHODS

We carried out a prospective international cohort study of adult patients (≥ 18 years of age) with HA-BSI treated in intensive care units (ICUs) between June 2019 and February 2021.

RESULTS

2600 patients from 333 ICUs in 52 countries were included. 78% HA-BSI were ICU-acquired. Median Sequential Organ Failure Assessment (SOFA) score was 8 [IQR 5; 11] at HA-BSI diagnosis. Most frequent sources of infection included pneumonia (26.7%) and intravascular catheters (26.4%). Most frequent pathogens were Gram-negative bacteria (59.0%), predominantly Klebsiella spp. (27.9%), Acinetobacter spp. (20.3%), Escherichia coli (15.8%), and Pseudomonas spp. (14.3%). Carbapenem resistance was present in 37.8%, 84.6%, 7.4%, and 33.2%, respectively. Difficult-to-treat resistance (DTR) was present in 23.5% and pan-drug resistance in 1.5%. Antimicrobial therapy was deemed adequate within 24 h for 51.5%. Antimicrobial resistance was associated with longer delays to adequate antimicrobial therapy. Source control was needed in 52.5% but not achieved in 18.2%. Mortality was 37.1%, and only 16.1% had been discharged alive from hospital by day-28.

CONCLUSIONS

HA-BSI was frequently caused by Gram-negative, carbapenem-resistant and DTR pathogens. Antimicrobial resistance led to delays in adequate antimicrobial therapy. Mortality was high, and at day-28 only a minority of the patients were discharged alive from the hospital. Prevention of antimicrobial resistance and focusing on adequate antimicrobial therapy and source control are important to optimize patient management and outcomes.

Epidemiology, Antifungal Susceptibility, and Risk Factors of Invasive Candidiasis in a Tertiary Hospital During a Four-Year Period

Background: Candida infections are a significant cause of morbidity and mortality in hospitalized patients. Acquired resistance to antifungal agents and strains with intrinsic resistance makes it hard to manage the infection. Objectives: We aimed to examine the risk factors of candidemia associated with patient mortality, the species causing candidemia, and their antifungal susceptibility. Methods: Patient data were collected from medical records retrospectively. MALDI-TOF MS was used to identify Candida species. Antifungal susceptibility testing was conducted by the colorimetric broth microdilution method. Results: A total of 155 patients were included in the study. The incidences of candidemia were 0.92, 0.72, 0.99, 0.97, and 2.28 per 1,000 cases in 2016, 2017, 2018, 2019, and 2020, respectively. Candida albicans accounted for 45% of all cases, followed by C. parapsilosis complex (28%), C. tropicalis (10%), and C. glabrata (8%). The 30-day crude mortality was 45%. There was no significant difference in mortality between C. albicans and non-albicans yeast species. The susceptibility rates for anidulafungin, micafungin, caspofungin, voriconazole, and fluconazole were as follows: 97%, 97%, 97%, 97%, and 90% in C. albicans, 95%, 95%, 98%, 72%, and 67% in C. parapsilosis complex, and 100%, 100%, 100%, 38%, and 63% in C. tropicalis. The susceptibility rates for anidulafungin, micafungin, and caspofungin in C. glabrata were 100%, 100%, and 92%, respectively. All 12 C. glabrata strains were susceptible-dose-dependent against fluconazole and uninterpretable for voriconazole. Conclusions: Incidences of candidemia and susceptibility patterns of strains may vary over time and amongst the regions. Candida albicans was the predominant strain, and echinocandins demonstrated the highest susceptibility rates against the most common species isolated in this study. Antifungal susceptibility tests are crucial in guiding patient treatment.

Impact of the "Zero Resistance" program on acquisition of multidrug-resistant bacteria in patients admitted to Intensive Care Units in Spain. A prospective, intervention, multimodal, multicenter study

OBJECTIVE

To assess the impact of a multimodal interventional project ("Zero Resistance") on the acquisition of multidrug-resistant bacteria (MDR-B) during the patient's ICU stay.

DESIGN

Prospective, open-label, interventional, multicenter study.

SETTING

103 ICUs.

PATIENTS

Critically ill patients admitted to the ICUs over a 27-month period.

INTERVENTIONS

Implementation of a bundle of 10 recommendations to prevent emergence and spread of MDR-B in the ICU.

MAIN VARIABLE OF INTEREST

Rate of patients acquiring MDR-B during their ICU stay, with differentiation between colonization and infection.

RESULTS

A total of 139,505 patients were included. In 5409 (3.9%) patients, 6020 MDR-B on ICU admission were identified, and in 3648 (2.6%) patients, 4269 new MDR-B during ICU stay were isolated. The rate of patients with MDR-B detected on admission increased significantly (IRR 1.43, 95% CI 1.31-1.56) (p<0.001) during the study period, with an increase of 32.2% between the initial and final monthly rates. On the contrary, the rate of patients with MDR-B during ICU stay decreased non-significantly (IRR 0.93, 95% CI 0.83-1.03) (p=0.174), with a 24.9% decrease between initial and final monthly rates. According to the classification into colonization or infection, there was a highly significant increase of MDR-B colonizations detected on admission (IRR 1.69, 95% CI 1.52-1.83; p<0.0001) and a very significant decrease of MDR-B-infections during ICU stay (IRR 0.67, 95% CI 0.57-0.80, p<0.0001).

CONCLUSIONS

The implementation of ZR project-recommendations was associated with a significantly reduction an infection produced by MDR-B acquired during the patient's ICU stay.

Treatment of Acinetobacter baumannii severe infections

Acinetobacter baumannii is a Gram-negative, multidrug-resistant (MDR) pathogen that causes nosocomial infections, especially in intensive care units (ICUs) and immunocompromised patients. A. baumannii has developed a broad spectrum of antimicrobial resistance, associated with a higher mortality rate among infected patients compared with other non-baumannii species. In terms of clinical impact, resistant strains are associated with increases in both in-hospital length of stay and mortality. A. baumannii can cause a variety of infections, especially ventilator-associated pneumonia, bacteremia, and skin wound infections, among others. The most common risk factors for the acquisition of MDR A. baumannii are previous antibiotic use, mechanical ventilation, length of ICU and hospital stay, severity of illness, and use of medical devices. Current efforts are focused on addressing all the antimicrobial resistance mechanisms described in A. baumannii, with the objective of identifying the most promising therapeutic scheme.

Prevention of hospital pathogen biofilm formation by antimicrobial peptide KWI18

This study investigated the antimicrobial and antibiofilm activity of KWI18, a new synthetic peptide. KWI18 was tested against planktonic cells and Pseudomonas aeruginosa and Candida parapsilosis biofilms. Time-kill and synergism assays were performed. Sorbitol, ergosterol, lipid peroxidation, and protein oxidation assays were used to gain insight into the mechanism of action of the peptide. Toxicity was evaluated against erythrocytes and Galleria mellonella. KWI18 showed antimicrobial activity, with minimum inhibitory concentration (MIC) values ranging from 0.5 to 10 μM. KWI18 at 10 × MIC reduced P. aeruginosa and C. parapsilosis biofilm formation and cell viability. Time-kill assays revealed that KWI18 inhibited the growth of P. aeruginosa in 4 h and that of C. parapsilosis in 6 h. The mechanism of action was related to ergosterol as well as induction of oxidative damage in cells and biofilms. Furthermore, KWI18 demonstrated low toxicity to erythrocytes and G. mellonella. KWI18 proved to be an effective antibiofilm agent, opening opportunities for the development of new antimicrobials.

Development and evaluation of uncertainty quantifying machine learning models to predict piperacillin plasma concentrations in critically ill patients

BACKGROUND

Beta-lactam antimicrobial concentrations are frequently suboptimal in critically ill patients. Population pharmacokinetic (PopPK) modeling is the golden standard to predict drug concentrations. However, currently available PopPK models often lack predictive accuracy, making them less suited to guide dosing regimen adaptations. Furthermore, many currently developed models for clinical applications often lack uncertainty quantification. We, therefore, aimed to develop machine learning (ML) models for the prediction of piperacillin plasma concentrations while also providing uncertainty quantification with the aim of clinical practice.

METHODS

Blood samples for piperacillin analysis were prospectively collected from critically ill patients receiving continuous infusion of piperacillin/tazobactam. Interpretable ML models for the prediction of piperacillin concentrations were designed using CatBoost and Gaussian processes. Distribution-based Uncertainty Quantification was added to the CatBoost model using a proposed Quantile Ensemble method, useable for any model optimizing a quantile function. These models are subsequently evaluated using the distribution coverage error, a proposed interpretable uncertainty quantification calibration metric. Development and internal evaluation of the ML models were performed on the Ghent University Hospital database (752 piperacillin concentrations from 282 patients). Ensuing, ML models were compared with a published PopPK model on a database from the University Medical Centre of Groningen where a different dosing regimen is used (46 piperacillin concentrations from 15 patients.).

RESULTS

The best performing model was the Catboost model with an RMSE and [Formula: see text] of 31.94-0.64 and 33.53-0.60 for internal evaluation with and without previous concentration. Furthermore, the results prove the added value of the proposed Quantile Ensemble model in providing clinically useful individualized uncertainty predictions and show the limits of homoscedastic methods like Gaussian Processes in clinical applications.

CONCLUSIONS

Our results show that ML models can consistently estimate piperacillin concentrations with acceptable and high predictive accuracy when identical dosing regimens as in the training data are used while providing highly relevant uncertainty predictions. However, generalization capabilities to other dosing schemes are limited. Notwithstanding, incorporating ML models in therapeutic drug monitoring programs seems definitely promising and the current work provides a basis for validating the model in clinical practice.

Effectiveness of a Multifaced Antibiotic Stewardship Program: A Pre-Post Study in Seven Italian ICUs

Multidrug resistance has become a serious threat for health, particularly in hospital-acquired infections. To improve patients’ safety and outcomes while maintaining the efficacy of antimicrobials, complex interventions are needed involving infection control and appropriate pharmacological treatments in antibiotic stewardship programs. We conducted a multicenter pre-post study to assess the impact of a stewardship program in seven Italian intensive care units (ICUs). Each ICU was visited by a multidisciplinary team involving clinicians, microbiologists, pharmacologists, infectious disease specialists, and data scientists. Interventions were targeted according to the characteristics of each unit. The effect of the program was measured with a panel of indicators computed with data from the MargheritaTre electronic health record. The median duration of empirical therapy decreased from 5.6 to 4.6 days and the use of quinolones dropped from 15.3% to 6%, both p < 0.001. The proportion of multi-drug-resistant bacteria (MDR) in ICU-acquired infections fell from 57.7% to 48.8%. ICU mortality and length of stay remained unchanged, indicating that reducing antibiotic administration did not harm patients’ safety. This study shows that our stewardship program successfully improved the management of infections. This suggests that policy makers should tackle multidrug resistance with a multidisciplinary approach based on continuous monitoring and personalised interventions.

A receptor-targeting AIE photosensitizer for selective bacterial killing and real-time monitoring of photodynamic therapy outcome

A receptor-targeting AIE photosensitizer (CE-TPA) is synthesized by conjugating cephalothin with a cationic D-A type AIE photosensitizer for selective killing of Gram-positive bacteria over Gram-negative bacteria and normal mammalian cells. By virtue of the strong photosensitization capability, CE-TPA exhibits efficient killing against Gram-positive methicillin-resistant Staphylococcus aureus. More importantly, the photodynamic bactericidal outcome can be conveniently reflected in a real-time fashion by the polarity-sensitive property of CE-TPA.

Comparative Efficacy of Tonic Chinese Herbal Injections for Treating Sepsis or Septic Shock: A Systematic Review and Bayesian Network Meta-Analysis of Randomized Controlled Trials

Background: Sepsis has high mortality and is responsible for significant healthcare costs. Chinese herbal injections (CHIs) have been widely used in China as a novel and promising treatment option for sepsis. Therefore, this study assessed and ranked the effectiveness of CHIs to provide more sights for the selection of sepsis treatment. Method: Eight databases were searched from their inception up to September 1, 2021. The methodological quality of included study was evaluated by the Revised Cochrane risk-of-bias tool for randomized trials. Then Bayesian network meta-analysis was performed by OpenBUGS 3.2.3 and STATA 14.0 software. The surface under the cumulative ranking curve (SUCRA) probability values were applied to rank the examined treatments. Publication bias was reflected by a funnel plot. Results: A total of 50 eligible randomized controlled trials involving 3,394 participants were identified for this analysis. Five CHIs including Shenfu injection, Shenmai injection, Shengmai injection, Shenqifuzheng injection, and Huangqi injection were included. The results of the NMA and sensitivity analysis showed that Shenqifuzheng (MD = -4.48, 95% CI = -5.59 to -3.24), Shenmai (MD = -3.38, 95% CI = -4.38 to -2.39), Shenfu (MD = -2.38, 95% CI = -3.03 to -1.70) and Shengmai (MD = -1.90, 95% CI = -3.47 to -0.31) combined with Western medicine (WM) had a superior effect in improving the APACHE II score. Based on SUCRA values, Shenqifuzheng injection (95.65%) ranked highest in the APACHE II score, followed by Shenmai (74%), Shenfu (47.1%), Shengmai (35.3%) and Huangqi injection (33.2%). Among the secondary outcomes, Shenmai injection was the most favorable intervention in reducing PCT and CRP levels, and Shenqifuzheng injection was the second favorable intervention in reducing CRP level. Shenfu injection combined with WM was more effective than the other treatments in decreasing the serum IL-6 and TNF-α levels and lowering the 28-days mortality. Regarding the improvement of immune function, Shenqifuzheng injections had obvious advantages. Conclusion: In conclusion, Shenqifuzheng injection was the optimum treatment regimen to improve APACHE II score, reduce CRP level, and regulate immune function. Shenfu injection was superior in reducing the expression of inflammatory factors and decreasing 28-days mortality. Nevertheless, more multicenter, diverse, and direct comparisons randomized controlled trials are needed to further confirm the results. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=254531, identifier CRD42021254531.

Association between Timing of Colonization and Risk of Developing Klebsiella pneumoniae Carbapenemase-Producing K. pneumoniae Infection in Hospitalized Patients

Colonization by KPC-producing Klebsiella pneumoniae (KPC-Kp) is associated with the risk of developing KPC-Kp infection. The impact of the time elapsed since a patient becomes colonized on this risk is not well known. An observational, prospective, longitudinal cohort study of colonized patients undergoing active rectal culture screening to rule out KPC-Kp colonization (July 2012 to November 2017). Patients with a positive culture at inclusion (colonized at start of follow-up) and those with a negative culture at inclusion who became colonized within 90 days (colonized during follow-up) were included in the analysis. CART analysis was used to dichotomize variables according to their association with infection. Kaplan–Meier infection-free survival curves and the log-rank test were used for group comparisons. Logistic regression was used to identify variables associated with KPC-Kp infection. Among 1310 patients included, 166 were colonized at the end of follow-up. Forty-seven out of 118 patients colonized at start of follow-up developed infection (39.8%) versus 31 out of 48 patients colonized during follow-up (64.6%; P = 0.006). Variables associated with KPC-Kp infection in the logistic regression analysis were: colonization detection during follow-up (OR, 2.74; 95% CI, 1.07 to 7.04; P = 0.03), Giannella risk score (OR, 1.51; 95% CI, 1.32 to 1.73; P < 0.001), high-risk ward (OR, 4.77; 95% CI, 1.61 to 14.10; P = 0.005) and urological manipulation after admission (OR, 3.69; 95% CI, 1.08 to 12.60; P = 0.04). In 25 out of 31 patients (80.6%) colonized during follow-up who developed KPC-Kp infection, infection appeared within 15 days after colonization. The risk of KPC-Kp infection was higher when colonization is recently acquired during hospitalization. In this prospective study, we concluded that the timing of colonization was a factor to assess when considering empirical treatment for suspected KPC-Kp infection and prophylaxis or infection control.

IMPORTANCE In this study, it was confirmed that patients who became colonized during hospitalization had a higher risk of developing KPC-Kp infection than hospitalized patients who were already colonized at the start of follow-up. Besides, the risk of infection in the group of patients who became colonized during follow-up was greater in the first weeks immediately after colonization was confirmed. Our findings support the need for designing preventive strategies for patients at the highest risk of infection development, including those admitted in high-risk hospital wards and those undergoing urological procedures.

Using Procalcitonin to Guide Antibiotic Escalation in Patients With Suspected Bacterial Infection: A New Application of Procalcitonin in the Intensive Care Unit

BACKGROUND

Procalcitonin (PCT) is efficient in reducing antibiotic usage without increasing complications for its sensitivity and specificity in detecting bacterial infection. However, its role in guiding antibiotic-spectrum escalation has not been studied. This study was performed to validate the role of PCT in indicating antibiotic spectrum escalation when pathogen results are unknown for ICU patients of suspected bacterial infections.

METHODS

This was a single-center retrospective study including patients who were admitted to Peking Union Medical College Hospital from January 2014 to June 2018 for suspected bacterial infections. Patients were divided into "escalation" or "non-escalation" groups according to the change of employed antibiotic spectrum before and after the occurrence of "PCT alert". The main study endpoint was the length of ICU stay (LIS), and LIS longer than 7 days was defined as "prolonged-ICU-stay (PIS)" while LIS equal to or shorter than 7 days was defined as "non-prolonged-ICU-stay(nPIS)". Demographics, clinical characteristics, and infection characteristics were compared between patients in the "nPIS" and "PIS" groups. Multivariable logistic regression was used to evaluate independent risk factors for PIS.

RESULTS

Totally, 1109 patients were included, and 654 in the PIS group, other 455 in the nPIS group. Respiratory infection was the main cause in both groups. Patients were older in PIS group than in nPIS group(PIS vs. nPIS: 58.99 ± 16.30 vs. 56.12 ± 15.93 years, P=0.002). The baseline Sequential Organ Failure Assessment (SOFA) score was 11.16 ± 7.33 and 9.73 ± 3.70 in PIS and nPIS groups. Fewer patients received antibiotic escalation in face of "PCT alert" in PIS group (PIS vs. nPIS: 27.68 vs.35.38%, P=0.014). In the multivariable logistic regression model, older age, higher heart rate, not undergoing surgery, higher baseline SOFA score, and not escalating antibiotics in face of "PCT alert" were associated with a prolonged ICU stay. The odds ratio of antibiotic escalation for PIS was 0.582 (95% CI: 0.365, 0.926, P=0.022).

CONCLUSIONS

Using PCT to guide antibiotic escalation when pathogen evidence is unavailable could be associated with a shorter length of ICU stay for ICU patients of suspected bacterial infection.

Regulatory T Cells: Angels or Demons in the Pathophysiology of Sepsis?

Sepsis is a syndrome characterized by life-threatening organ dysfunction caused by the dysregulated host response to an infection. Sepsis, especially septic shock and multiple organ dysfunction is a medical emergency associated with high morbidity, high mortality, and prolonged after-effects. Over the past 20 years, regulatory T cells (Tregs) have been a key topic of focus in all stages of sepsis research. Tregs play a controversial role in sepsis based on their heterogeneous characteristics, complex organ/tissue-specific patterns in the host, the multi-dimensional heterogeneous syndrome of sepsis, the different types of pathogenic microbiology, and even different types of laboratory research models and clinical research methods. In the context of sepsis, Tregs may be considered both angels and demons. We propose that the symptoms and signs of sepsis can be attenuated by regulating Tregs. This review summarizes the controversial roles and Treg checkpoints in sepsis.

Isolation of extensively drug resistant Acinetobacter baumannii from environmental surfaces inside intensive care units

BACKGROUND

Acinetobacter baumannii is a nosocomial pathogen that has emerged as a major threat in the health-care settings, particularly intensive care units (ICUs). The aim of this study was to investigate the prevalence of A. baumannii in the environment of intensive care and emergency units in 4 hospitals in Jordan.

METHODS

A total of 311 surface and 26 air samples were collected from 6 different ICUs and 2 emergency units. Examined high-touch surfaces included bed rails, sinks, food tables, trolley handles, ventilator inlets, blankets, sheets, door handles, light switches, bedside tables and drawers, curtains, normal saline stands and neonatal incubators. A. baumannii isolates were identified by CHROMagar and confirmed using 2 different PCR assays. All obtained isolates were characterized for their antibiotic resistance phenotypes, biofilm formation capacities and were typed by multi-locus sequence typing.

RESULTS

Of the 337 samples, 24 A. baumannii isolates were recovered, mostly from surfaces in the internal medicine ICUs. Among the 24 isolates, 10 isolates were classified as extensively-resistant (XDR), harbored the bla_OXA-23 like gene and able to form biofilms with varying capacities. ST2 was the most frequent sequence type, with all ST2 isolates classified as XDRs.

CONCLUSIONS

Our results showed that high-touch surfaces of adult and pediatric ICUs were contaminated with XDR A. baumannii isolates. Therefore, the cleaning practices of the surfaces and equipment surrounding ICU patients should be optimized, and health-care workers should continuously wash their hands and change their gloves constantly to control the spread of this pathogen.

Prevenção e controle de resistência aos antimicrobianos na Atenção Primária à Saúde: evidências para políticas

Resumo A resistência aos antimicrobianos é um problema mundial que põe em risco a segurança da saúde da população. O objetivo deste artigo é identificar e avaliar estratégias para prevenção e controle de resistência microbiana, bem como barreiras para sua implementação em serviços de Atenção Primária à Saúde (APS). Realizou-se uma síntese de evidências para políticas. As buscas de evidências foram realizadas entre novembro/dezembro de 2018, em 13 bases de dados. Um diálogo deliberativo foi realizado para validação dos resultados e levantamento de barreiras e facilitadores para implementação das estratégias. As 13 revisões sistemáticas incluídas mostraram que intervenções com foco em educação, uso de sistemas eletrônicos e biomarcadores reduziram o consumo e prescrição de antimicrobianos. É um obstáculo à implementação a expectativa de usuários/cuidadores em receber prescrição de antibióticos, e são facilitadores as ações educativas que envolvem profissionais de saúde. O uso racional de medicamentos se impõe na APS com vistas à prevenção da resistência dos microrganismos aos antibióticos. As intervenções identificadas neste estudo podem ser implementadas isoladamente ou em conjunto, conforme o contexto local.

Main-chain flexibility and hydrophobicity of ionenes strongly impact their antimicrobial activity: an extended study on drug resistance strains and Mycobacterium

The spread of antibiotic-resistant pathogens and the resurgence of tuberculosis disease are major motivations to search for novel antimicrobial agents. Some promising candidates in this respect are cationic polymers, also known as synthetic mimics of antimicrobial peptides (SMAMPs), which act through the membrane-lytic mechanism. Development of resistance toward SMAMPs is less likely than toward currently employed antibiotics; however, further studies are needed to better understand their structure–activity relationship. The main objective of this work is to understand the cross-influence of hydrophobicity, main-chain flexibility, and the topology of ionenes (polycations containing a cationic moiety within the main-chain) on activity. To fulfill this goal, a library of ionenes was developed and compared with previously investigated molecules. The obtained compounds display promising activity against the model microorganisms and drug-resistance clinical isolates, including Mycobacterium tuberculosis. The killing efficiency was also investigated, and results confirm a strong effect of hydrophobicity, revealing higher activity for molecules possessing the flexible linker within the polymer main-chain.

A high significance of the main chain flexibility and an unexpected effect of hydrophobicity on the biological activity in series of ionenes was observed. The most potent among the tested polycations showed high activity toward clinical bacterial isolates.

Klebsiella oxytoca Complex: Update on Taxonomy, Antimicrobial Resistance, and Virulence

Klebsiella oxytoca is actually a complex of nine species-Klebsiella grimontii, Klebsiella huaxiensis, Klebsiella michiganensis, K. oxytoca, Klebsiella pasteurii, Klebsiella spallanzanii, and three unnamed novel species. Phenotypic tests can assign isolates to the complex, but precise species identification requires genome-based analysis. The K. oxytoca complex is a human commensal but also an opportunistic pathogen causing various infections, such as antibiotic-associated hemorrhagic colitis (AAHC), urinary tract infection, and bacteremia, and has caused outbreaks. Production of the cytotoxins tilivalline and tilimycin lead to AAHC, while many virulence factors seen in Klebsiella pneumoniae, such as capsular polysaccharides and fimbriae, have been found in the complex; however, their association with pathogenicity remains unclear. Among the 5,724 K. oxytoca clinical isolates in the SENTRY surveillance system, the rates of nonsusceptibility to carbapenems, ceftriaxone, ciprofloxacin, colistin, and tigecycline were 1.8%, 12.5%, 7.1%, 0.8%, and 0.1%, respectively. Resistance to carbapenems is increasing alarmingly. In addition to the intrinsic bla_OXY, many genes encoding β-lactamases with varying spectra of hydrolysis, including extended-spectrum β-lactamases, such as a few CTX-M variants and several TEM and SHV variants, have been found. bla_KPC-2 is the most common carbapenemase gene found in the complex and is mainly seen on IncN or IncF plasmids. Due to the ability to acquire antimicrobial resistance and the carriage of multiple virulence genes, the K. oxytoca complex has the potential to become a major threat to human health.

Population Pharmacokinetics of Meropenem in Critically Ill Korean Patients and Effects of Extracorporeal Membrane Oxygenation

Limited studies have investigated population pharmacokinetic (PK) models and optimal dosage regimens of meropenem for critically ill adult patients using the probability of target attainment, including patients receiving extracorporeal membrane oxygenation (ECMO). A population PK analysis was conducted using non-linear mixed-effect modeling. Monte Carlo simulation was used to determine for how long the free drug concentration was above the minimum inhibitory concentration (MIC) at steady state conditions in patients with various degrees of renal function. Meropenem PK in critically ill patients was described using a two-compartment model, in which glomerular filtration rate was identified as a covariate for clearance. ECMO did not affect meropenem PK. The simulation results showed that the current meropenem dosing regimen would be sufficient for attaining 40%fT_>MIC for Pseudomonas aeruginosa at MIC ≤ 4 mg/L. Prolonged infusion over 3 h or a high-dosage regimen of 2 g/8 h was needed for MIC > 2 mg/L or in patients with augmented renal clearance, for a target of 100%fT_>MIC or 100%fT_>4XMIC. Our study suggests that clinicians should consider prolonged infusion or a high-dosage regimen of meropenem, particularly when treating critically ill patients with augmented renal clearance or those infected with pathogens with decreased in vitro susceptibility, regardless of ECMO support.

Surviving Sepsis Campaign: Research Opportunities for Infection and Blood Purification Therapies

Patients with infection can develop sepsis, and their mortality can be high. An important aspect in the treatment of sepsis is adequate management of the infection.

Antimicrobial stewardship, therapeutic drug monitoring and infection management in the ICU: results from the international A- TEAMICU survey

BACKGROUND

Severe infections and multidrug-resistant pathogens are common in critically ill patients. Antimicrobial stewardship (AMS) and therapeutic drug monitoring (TDM) are contemporary tools to optimize the use of antimicrobials. The A-TEAMICU survey was initiated to gain contemporary insights into dissemination and structure of AMS programs and TDM practices in intensive care units.

METHODS

This study involved online survey of members of ESICM and six national professional intensive care societies.

RESULTS

Data of 812 respondents from mostly European high- and middle-income countries were available for analysis. 63% had AMS rounds available in their ICU, where 78% performed rounds weekly or more often. While 82% had local guidelines for treatment of infections, only 70% had cumulative antimicrobial susceptibility reports and 56% monitored the quantity of antimicrobials administered. A restriction of antimicrobials was reported by 62%. TDM of antimicrobial agents was used in 61% of ICUs, mostly glycopeptides (89%), aminoglycosides (77%), carbapenems (32%), penicillins (30%), azole antifungals (27%), cephalosporins (17%), and linezolid (16%). 76% of respondents used prolonged/continuous infusion of antimicrobials. The availability of an AMS had a significant association with the use of TDM.

CONCLUSIONS

Many respondents of the survey have AMS in their ICUs. TDM of antimicrobials and optimized administration of antibiotics are broadly used among respondents. The availability of antimicrobial susceptibility reports and a surveillance of antimicrobial use should be actively sought by intensivists where unavailable. Results of this survey may inform further research and educational activities.

Impact of a restrictive antibiotic policy on the acquisition of extended-spectrum beta-lactamase-producing Enterobacteriaceae in an endemic region: a before-and-after, propensity-matched cohort study in a Caribbean intensive care unit

BACKGROUND

High-level antibiotic consumption plays a critical role in the selection and spread of extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) in the ICU. Implementation of a stewardship program including a restrictive antibiotic policy was evaluated with respect to ESBL-E acquisition (carriage and infection).

METHODS

We implemented a 2-year, before-and-after intervention study including all consecutive adult patients admitted for > 48 h in the medical-surgical 26-bed ICU of Guadeloupe University Hospital (French West Indies). A conventional strategy period (CSP) including a broad-spectrum antibiotic as initial empirical treatment, followed by de-escalation (period before), was compared to a restrictive strategy period (RSP) limiting broad-spectrum antibiotics and shortening their duration. Antibiotic therapy was delayed and initiated only after microbiological identification, except for septic shock, severe acute respiratory distress syndrome and meningitis (period after). A multivariate Cox proportional hazard regression model adjusted on propensity score values was performed. The main outcome was the median time of being ESBL-E-free in the ICU. Secondary outcome included all-cause ICU mortality.

RESULTS

The study included 1541 patients: 738 in the CSP and 803 in the RSP. During the RSP, less patients were treated with antibiotics (46.8% vs. 57.9%; p < 0.01), treatment duration was shorter (5 vs. 6 days; p < 0.01), and administration of antibiotics targeting anaerobic pathogens significantly decreased (65.3% vs. 33.5%; p < 0.01) compared to the CSP. The incidence of ICU-acquired ESBL-E was lower (12.1% vs. 19%; p < 0.01) during the RSP. The median time of being ESBL-E-free was 22 days (95% CI 16-NA) in the RSP and 18 days (95% CI 16-21) in the CSP. After propensity score weighting and adjusted analysis, the median time of being ESBL-E-free was independently associated with the RSP (hazard ratio, 0.746 [95% CI 0.575-0.968]; p = 0.02, and hazard ratio 0.751 [95% CI 0.578-0.977]; p = 0.03, respectively). All-cause ICU mortality was lower in the RSP than in the CSP (22.5% vs. 28.6%; p < 0.01).

CONCLUSIONS

Implementation of a program including a restrictive antibiotic strategy is feasible and is associated with less ESBL-E acquisition in the ICU without any worsening of patient outcome.

Blood Stream Infections from MDR Bacteria

BACKGROUND

Bloodstream infections (BSIs) constitute a growing public health concern, are among the most severe nosocomial pathologies, and are considered a worldwide cause of unfaithful outcomes, increasing treatment costs and diagnostic uncertainties. BSIs are one of the most frequent lethal conditions that are managed in intensive care units (ICUs). In the case of septic shock, immune deficiency, and delayed treatment, even with adequate antimicrobial therapy and/or source control, the outcomes are often unfavorable.

METHODS

this review article summarizes the epidemiological and microbiological characteristics of BSIs with a particular focus on ICU acquired BSIs (ICU-BSIs), which are usually caused by multidrug-resistant (MDR) pathogens. For this reason, their antimicrobial resistance patterns and therapeutic options have also been compiled.

RESULTS

ICU-acquired BSIs prevail in 5-7% of ICU patients. Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii, and Pseudomonas aeruginosae are the pathogens most often responsible for MDR infections. MDR Enterobacteriaceae have seen their prevalence increase from 6.2% (1997-2000) to 15.8% (2013-2016) in recent years.

CONCLUSIONS

Considering that prevention and treatment of sepsis is nowadays considered a global health priority by the World Health Organization, it is our obligation to invest more resources into solving or reducing the spread of these unfaithful infections. It is relevant to identify patients with risk factors that make them more susceptible to BSIs, to guarantee earlier molecular or microbiological diagnoses, and more rapidly appropriate treatment by using de-escalation strategies where possible.

Understanding decisions about antibiotic prescribing in ICU: an application of the Necessity Concerns Framework

BACKGROUND

Antibiotics are extensively prescribed in intensive care units (ICUs), yet little is known about how antibiotic-related decisions are made in this setting. We explored how beliefs, perceptions and contextual factors influenced ICU clinicians' antibiotic prescribing.

METHODS

We conducted 4 focus groups and 34 semistructured interviews with clinicians involved in antibiotic prescribing in four English ICUs. Focus groups explored factors influencing prescribing, whereas interviews examined decision-making processes using two clinical vignettes. Data were analysed using thematic analysis, applying the Necessity Concerns Framework.

RESULTS

Clinicians' antibiotic decisions were influenced by their judgement of the necessity for prescribing/not prescribing, relative to their concerns about potential adverse consequences. Antibiotic necessity perceptions were strongly influenced by beliefs that antibiotics would protect patients from deterioration and themselves from the ethical and legal consequences of undertreatment. Clinicians also reported concerns about prescribing antibiotics. These generally centred on antimicrobial resistance; however, protecting the individual patient was prioritised over these societal concerns. Few participants identified antibiotic toxicity concerns as a key influencer. Clinical uncertainty often complicated balancing antibiotic necessity against concerns. Decisions to start or continue antibiotics often represented 'erring on the side of caution' as a protective response in uncertainty. This approach was reinforced by previous experiences of negative consequences ('being burnt') which motivated prescribing 'just in case' of an infection. Prescribing decisions were also context-dependent, exemplified by a lower perceived threshold to prescribe antibiotics out-of-hours, input from external team members and local prescribing norms.

CONCLUSION

Efforts to improve antibiotic stewardship should consider clinicians' desire to protect with a prescription. Rapid molecular microbiology, with appropriate communication, may diminish clinicians' fears of not prescribing or of using narrower-spectrum antibiotics.