Inadequate antimicrobial treatment of infections: a risk factor for hospital mortality among critically ill patients

Pharmacokinetic/Pharmacodynamic Analysis of Extended/Two-Step Infusion Ceftazidime/Avibactam in Children With Gram-Negative Bacterial Infections

PURPOSE

To simulate the pharmacokinetic/pharmacodynamic (PK/PD) exposure of ceftazidime/avibactam (CZA) in children with gram-negative bacterial infections, and explore the appropriateness of the CZA standard dosing regimen (STD), further optimize the dosing regimen by extended/two-step infusion.

METHODS

Monte Carlo simulations were performed to calculate the probability of target attainment (PTA) and cumulative fraction of response (CFR) of CZA with varying weight in two age groups (≥6-12 and ≥12-18 years old, respectively), utilizing PK parameters and PD data (from the EUCAST as well as the published data on US children). The simulated dosing regimens included STD and extended/two-step infusion.

FINDINGS

When the PK/PD target for ceftazidime was set at 50% of time that free drug concentrations remain above the minimum inhibitory concentration of the pathogen during the dosing interval (50% fT > MIC), the CZA STD achieved PTAs of ≥90% at susceptibility breakpoint (MIC = 8 mg/L) for children in weighed 15-30 kg (≥6-12years old) and 35-45 kg (≥12-18 years old). However, when the PK/PD target for ceftazidime was set at 100% fT > MIC, none could achieve PTAs of ≥90%. The CFR results showed that the STD couldn't provide CFRs ≥90% in all children, but extended infusion or two-step infusion could achieve the target CFRs in all children based on the MIC distribution of US children, and improve the CFRs based on EUCAST's MIC distribution. Compared with extended infusion, two-step infusion could reduce total infusion time in partial patients.

IMPLICATIONS

The current STD of CZA may not adequately meet the therapeutic requirements in children, thus it is recommended to optimize the dosing regimen by extended/two-step infusion or increasing the daily dose, guided by therapeutic drug monitoring.

Optimizing Therapeutic Drug Monitoring of Anti-infectives: Patient and Clinical Setting Considerations

Therapeutic drug monitoring (TDM) plays an essential role in personalized medicine, especially for anti-infective agents, due to the high global burden of infection-related morbidity and mortality. Achieving optimal therapy for antibacterial, antifungal, antiviral, and antimycobacterial agents can be challenging due to significant variability in pharmacokinetics/pharmacodynamics among different patients. This review explores the implementation of TDM and patient-related challenges using different anti-infective agents as examples across different clinical settings. TDM enables the implementation of a precision medicine approach, tailoring drug dosing to individual patient characteristics, disease states, and treatment variables.

Enrichment of Microbial DNA in Plasma to Improve Pathogen Detection in Sepsis: A Pilot Study

BACKGROUND

Diagnosis of sepsis and timely identification of pathogens in critically ill patients remains challenging. Plasma metagenomic sequencing to detect microbial cell-free DNA (mDNA) has shown promise, but low abundance of mDNA in plasma limits sensitivity and necessitates high sequencing depth. mDNA is shorter and more fragmented than human cell-free DNA. Here, we evaluated whether combining single-stranded DNA (ssDNA) sequencing library preparation and size selection can enrich mDNA and improve pathogen detection.

METHODS

We prospectively enrolled 48 trauma patients and collected daily blood samples during the first 10 days of intensive care unit (ICU) admission. For patients with culture-proven infections, we extracted plasma DNA, prepared double-stranded DNA (dsDNA) and ssDNA sequencing libraries, and applied size selection to exclude fragments >110 bp. Following sequencing, we performed taxonomic classification, and evaluated differences in mDNA fractions and in sensitivity for pathogen detection (compared to background noise).

RESULTS

We analyzed 46 plasma samples from 5 patients who developed culture-proven infections, including 17 samples coincident with positive microbial cultures. Size-selected ssDNA libraries showed the total mDNA fraction 204-fold higher on average than conventional dsDNA libraries (P < 0.0001). However, for pathogen-specific DNA (at the genus level), the highest sensitivity was observed in size-selected dsDNA (82%), compared to dsDNA (41%), ssDNA (71%), and size-selected ssDNA (35%) library preparations.

CONCLUSIONS

Our results demonstrate that combining ssDNA library preparation together with fragment size selection improves mDNA yield, potentially reducing sequencing requirements. However, at the genus level, this combination also increases background noise, which limits sensitivity for pathogen detection.

Reply to Comment on: Clinical Performance of Existing Diagnostic Criteria for Pneumonia in Older Emergency Patients

See the related comment by Turgut et al. in this issue.

Subtherapeutic Meropenem Antibiotic Exposure in Children With Septic Shock Assessed by Noncompartmental Pharmacokinetic Analysis in a Prospective Dataset

OBJECTIVES

To define meropenem plasma concentrations and pharmacodynamic exposure metrics in children with septic shock during the first 3 days of PICU hospitalization.

DESIGN

Pharmacokinetic sampling was undertaken in 19 subjects receiving standard meropenem dosing (20 mg/kg/dose, 8 hr) recruited from March 2019 to March 2022. Sampling occurred once each day following meropenem given 24 hours apart, during the first 3 PICU days. Data analysis was completed in 2023 and noncompartmental analysis was performed to assess pharmacodynamic exposure targets for sepsis. Clearance and volume of distribution at 20 mg/kg/dose were used to simulate mean exposures at 40 and 60 mg/kg/dose.

SETTING

PICU in a tertiary care center.

SUBJECTS

Patients 4 weeks old or older with hypotension requiring fluid resuscitation and vasopressor therapy, receiving meropenem as empiric therapy for sepsis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Augmented renal clearance (ARC) was documented in eight of 19 subjects, previously associated with subtherapeutic plasma concentrations, while three of 19 had acute kidney injury and decreased renal clearance. When assessed by pharmacodynamic exposure targets for sepsis (plasma meropenem concentrations above the minimum inhibitory concentration [MIC] of Pseudomonas aeruginosa for 70% or 100% of the dosing interval), ten of 19 and nine of 19 children, respectively, had subtherapeutic plasma meropenem exposures during PICU day 1, even for pathogens with an MIC considered "susceptible" by U.S. Food and Drug Administration criteria. Therapeutic meropenem pharmacodynamic exposures were associated with a positive 24-hour fluid balance on PICU day 1 and a negative 24-hour fluid balance by day 3, although profound variability was noted in fluid administered and renal output.

CONCLUSIONS

Given the variability in meropenem systemic exposure in pediatric septic shock, therapeutic drug monitoring, or monitoring for ARC, is suggested during the first days of hospitalization to allow daily assessments of dosing needs to achieve pharmacodynamic exposure targets for sepsis.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2024

The 2024 revised edition of the Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock (J-SSCG 2024) is published by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine. This is the fourth revision since the first edition was published in 2012. The purpose of the guidelines is to assist healthcare providers in making appropriate decisions in the treatment of sepsis and septic shock, leading to improved patient outcomes. We aimed to create guidelines that are easy to understand and use for physicians who recognize sepsis and provide initial management, specialized physicians who take over the treatment, and multidisciplinary healthcare providers, including nurses, physical therapists, clinical engineers, and pharmacists. The J-SSCG 2024 covers the following nine areas: diagnosis of sepsis and source control, antimicrobial therapy, initial resuscitation, blood purification, disseminated intravascular coagulation, adjunctive therapy, post-intensive care syndrome, patient and family care, and pediatrics. In these areas, we extracted 78 important clinical issues. The GRADE (Grading of Recommendations Assessment, Development and Evaluation) method was adopted for making recommendations, and the modified Delphi method was used to determine recommendations by voting from all committee members. As a result, 42 GRADE-based recommendations, 7 good practice statements, and 22 information-to-background questions were created as responses to clinical questions. We also described 12 future research questions.

Development of a Weighted-Incidence Syndromic Combination Antibiogram (WISCA) to guide empiric antibiotic treatment for ventilator-associated pneumonia in a Mexican tertiary care university hospital

BACKGROUND

Ventilator-associated pneumonia (VAP) is a significant nosocomial infection in critically ill patients, leading to high morbidity, mortality, and increased healthcare costs. The diversity of local microbiology and resistance patterns complicates the empirical treatment selection. The Weighted-Incidence Syndromic Combination Antibiogram (WISCA) offers an innovative tool to optimize empirical antibiotic therapy by integrating local microbiological data and resistance profiles.

OBJECTIVE

To develop a WISCA tailored for VAP in a Mexican tertiary care university hospital, aiming to enhance empirical antibiotic coverage by addressing the unique pathogen distribution and resistance patterns within the institution.

METHODS

This retrospective study included 197 VAP episodes from 129 patients admitted to a critical care unit between June 2021 and June 2024. Clinical and microbiological data, including pathogen susceptibility profiles, were analyzed using a Bayesian hierarchical model to evaluate the coverage of multiple antibiotic regimens. We also assessed the current impact of inappropriate empiric or directed treatment on in-hospital mortality using Cox regression models to support the development of a WISCA model.

RESULTS

The median age of the patients was 44 years (IQR 35-56), with Acinetobacter baumannii (n = 71), Enterobacterales (n = 53) and Pseudomonas aeruginosa (n = 36) identified as the most frequently isolated pathogens. The developed WISCA models showed variable coverage based on antibiotic regimens and the duration of invasive mechanical ventilation (IMV). Inappropriate directed therapy during the VAP episode was associated with increased mortality, as were the diagnosis of Acute Respiratory Distress Syndrome (ARDS) and a high Sequential Organ Failure Assessment (SOFA) score (p < 0.01).

CONCLUSIONS

The tailored WISCA with Bayesian hierarchical modeling provided more adaptive, subgroup-specific estimates and managed uncertainty better compared to fixed models. The implementation of this WISCA model demonstrated potential to optimize antibiotic strategies and improve clinical outcomes in critically ill patients in our hospital.

TOPIC

Optimizing Empirical Antibiotic Therapy for Ventilator-Associated Pneumonia Using a Weighted-Incidence Syndromic Combination Antibiogram in a Mexican Tertiary Care Hospital.

Impact of rapid antibiotic susceptibility testing for Gram-negative bacteremia varies by pathogen type and resistance: a secondary analysis of the RAPIDS GN trial

In this secondary analysis of 386 subjects with Gram-negative bacteremia enrolled in the RAPIDS GN trial, rapid antibiotic susceptibility testing had a greater benefit on the management of bacteremia caused by antibiotic-resistant compared to antibiotic-susceptible isolates, especially for Escherichia coli, Klebsiella species, and Proteus species.IMPORTANCERapid blood culture diagnostics are costly, and their use has not demonstrated clear clinical benefit for patients with Gram-negative sepsis, possibly because prior trials did not enroll sufficient numbers of patients with antibiotic-resistant infections. This analysis of patients with sepsis previously enrolled in a randomized controlled clinical trial demonstrates that rapid susceptibility testing of bacteria from blood cultures had the greatest impact for patients with antibiotic-resistant infections. Specifically, after rapid testing results were reported, patients infected with resistant bacteria received appropriate antibiotic therapy more quickly than patients with susceptible bacteria. These findings highlight the need to evaluate blood culture diagnostics in areas with high antibiotic resistance where these diagnostics are likely to have the greatest impact.

Diagnostic Performance and Impact on Antimicrobial Treatment of a Multiplex Polymerase Chain Reaction in Critically Ill Patients With Pneumonia: A Multicenter Observational Study (The MORICUP-PCR Study: Morocco ICU Pneumonia-PCR study)

OBJECTIVES

Managing severe pneumonia remains a challenge. Rapid diagnostic tests, such as multiplex polymerase chain reaction (mPCR), facilitate quick microorganism identification and may enable timely and appropriate antimicrobial therapy. However, studies from low-income countries are scarce. This study aimed to evaluate the diagnostic characteristics of mPCR and its impact on antibiotic therapy and outcomes in critically ill patients with pneumonia.

DESIGN

Multicenter observational study.

SETTING

Twelve ICUs across Morocco.

PATIENTS

Adult patients with pneumonia requiring invasive mechanical ventilation, including community-acquired pneumonia (CAP), hospital-acquired pneumonia (HAP), and ventilator-associated pneumonia (VAP).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Respiratory samples were analyzed using both mPCR and conventional microbiological methods. The diagnostic performance of mPCR was evaluated, including its sensitivity and specificity. Additionally, the appropriateness of mPCR-induced modifications in empiric antibiotic therapy and their impact on patient outcomes were assessed. A total of 210 patients were included, with a median age of 50 years (range, 33-67 yr), of whom 66.2% were male. Pneumonia types were distributed as 30% CAP, 58% VAP, and 12% HAP. mPCR demonstrated a sensitivity of 96.9% (95% CI, 92.3-99.2%) and a specificity of 92% (95% CI, 91-93%). Following mPCR, antibiotic therapy modifications were observed in 58% of patients (n = 122), including de-escalation or cessation in 11% (n = 23), escalation in 26.5% (n = 56), adequacy adjustments in 7.5% (n = 16), and initiation of antibiotics in 13% (n = 27). The appropriateness of antibiotic therapy increased significantly from 38.7% (n = 83) to 67% (n = 141; difference, 27.5%; 95% CI, 18.3-36.7; p < 0.0001). Generalized mixed model analysis revealed that appropriate post-mPCR antibiotic therapy was associated with reduced mortality (adjusted odds ratio, 0.37; 95% CI, 0.15-0.93; p = 0.038).

CONCLUSIONS

Our findings suggest that the use of mPCR is associated with a significant improvement in the appropriateness of empiric antibiotic therapy and is also associated with a positive impact on the outcome of patients with pneumonia.

Aztreonam-avibactam versus meropenem for the treatment of serious infections caused by Gram-negative bacteria (REVISIT): a descriptive, multinational, open-label, phase 3, randomised trial

BACKGROUND

There is a need for additional therapeutic options for serious infections caused by Gram-negative pathogens. In the phase 3, descriptive REVISIT study, we investigated the safety and efficacy of aztreonam-avibactam in the treatment of complicated intra-abdominal infections or hospital-acquired pneumonia or ventilator-associated pneumonia (HAP-VAP) caused, or suspected to be caused, by Gram-negative bacteria.

METHODS

This prospective, multinational, open-label, central assessor-masked study enrolled adults who were hospitalised with a complicated intra-abdominal infection or HAP-VAP. Patients were randomly allocated via block randomisation using interactive response technology stratified by infection type in a 2:1 ratio to aztreonam-avibactam (with metronidazole for complicated intra-abdominal infection) or meropenem with or without colistin for 5-14 days for complicated intra-abdominal infection or 7-14 days for HAP-VAP. The primary endpoint was clinical cure at the test-of-cure visit (within 3 days before or after day 28) in the intention-to-treat (ITT) population. Secondary endpoints included 28-day mortality in the ITT population and safety in patients in the ITT population who received study drug (safety analysis set). No formal hypothesis testing was planned. The study was registered with ClinicalTrials.gov (NCT03329092) and EudraCT (2017-002742-68) and is complete.

FINDINGS

Between April 5, 2018, and Feb 23, 2023, we screened 461 patients. 422 patients were enrolled and randomly allocated (282 in the aztreonam-avibactam group and 140 in the meropenem group, forming the ITT analysis set), of whom ten patients (seven in the aztreonam-avibactam group and three in the meropenem group) were randomly allocated but did not receive study treatment. 271 (64%) of 422 patients had at least one Gram-negative pathogen from an adequate specimen identified at baseline. The most frequent baseline pathogens were Enterobacterales (252 [93%] of 271). Overall, 19 (24%) of 80 isolates tested for carbapenemases were carbapenemase-positive (serine, metallo-β-lactamase, or both). 193 (68·4%) of 282 patients in the aztreonam-avibactam group and 92 (65·7%) of 140 in the meropenem group had clinical cure at the test-of-cure visit (treatment difference 2·7% [95% CI -6·6 to 12·4]). For patients with complicated intra-abdominal infection, the adjudicated clinical cure rate was 76·4% (159 of 208) for the aztreonam-avibactam group and 74·0% (77 of 104) for the meropenem group. Cure rates in patients with HAP-VAP were 45·9% (34 of 74) for aztreonam-avibactam and 41·7% (15 of 36) for meropenem. 28-day all-cause mortality rates were 4% (12 of 282) for aztreonam-avibactam and 7% (ten of 140) for meropenem; in patients with complicated intra-abdominal infection, mortality was 2% (four of 208) and 3% (three of 104) for aztreonam-avibactam and meropenem, respectively, and in patients with HAP-VAP, mortality was 11% (eight of 74) and 19% (seven of 36), respectively. Aztreonam-avibactam was generally well tolerated, and safety findings were consistent with the known safety profile of aztreonam monotherapy. There were no treatment-related serious adverse events in the aztreonam-avibactam group.

INTERPRETATION

These phase 3 efficacy and safety data provide support for aztreonam-avibactam as a potential therapeutic option for complicated intra-abdominal infection or HAP-VAP caused by Gram-negative bacteria.

FUNDING

Pfizer.

Characteristics and risk factors for infection in patients with ANCA-associated vasculitis: A systematic review and meta-analysis

OBJECTIVE

To summarize the characteristics and risk factors for infection in patients with anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV).

METHODS

PubMed, Embase, and Cochrane Library databases were searched for relevant articles from database inception to November 2023. The prevalence, odds ratio (OR), and mean difference (MD) with 95 % confidence intervals (CIs) were pooled using a random-effects model. Sensitivity and subgroup analysis were also performed.

RESULTS

Forty-one studies with 5343 patients with AAV were included, of whom 2890 patients experienced an infection. The pooled prevalence was 54.6 % (95 % CI, 48.4 % to 61.1 %) for all infections and 35.8 % (95 % CI, 31.0 % to 40.8 %) for severe infections; and prevalence of Pneumocystis jirovecii pneumonia, aspergillosis, candidiasis, cryptococcosis, herpes zoster, cytomegalovirus, and specific bacterial infections were pooled. The respiratory system was the most common infection site, followed by blood, urinary tract, skin and soft tissue, and digestive infections. Risk factors for infection included older age, end-stage renal disease, dialysis, diabetes, smoking, kidney and lung involvement, leukopenia; higher Birmingham Vasculitis Activity Score, and serum creatinine and C-reactive protein levels; and lower hemoglobin levels, and platelet and CD4 counts. In addition, use of cyclophosphamide, steroid pulse therapy, plasma exchange, and higher initial glucocorticoid dose were associated with significantly increased risk of infection.

CONCLUSION

In patients with AAV, therapy should take risk factors for infection into account. Risk factors should be modified wherever possible. Physicians should be familiar with the common infection sites and pathogens, and consider empiric therapy covering common pathogens for life-threatening infections.

Modeling and simulation of distribution and drug resistance of major pathogens in patients with respiratory system infections

BACKGROUND

Respiratory tract infections (RTIs) are one of the leading causes of morbidity and mortality worldwide. The increase in antimicrobial resistance in respiratory pathogens poses a major challenge to the effective management of these infections.

OBJECTIVE

To investigate the distribution of major pathogens of RTIs and their antimicrobial resistance patterns in a tertiary care hospital and to develop a mathematical model to explore the relationship between pathogen distribution and antimicrobial resistance.

METHODS

Five hundred patients with RTIs were included in the study and 475 bacterial strains were isolated from their respiratory specimens. Antimicrobial susceptibility testing and analysis of influencing factors were performed. A mathematical model was developed to simulate the relationship between pathogen distribution and drug resistance.

RESULTS

The most common pathogens were Streptococcus pneumoniae (30%), Haemophilus influenzae (20%), Pseudomonas aeruginosa (15%), Staphylococcus aureus (10%) and Klebsiella pneumoniae (10%). The distribution of pathogens varied according to age group and type of RTIs, with higher proportions of Pseudomonas aeruginosa and Staphylococcus aureus in hospital-acquired and ventilator-associated pneumonia. Isolated pathogens showed high and increasing rates of resistance to commonly used antibiotics. Model simulations suggest that a shift in the distribution of pathogens toward more resistant strains may lead to a significant increase in overall resistance rates, even if antibiotic use patterns remain unchanged.

CONCLUSION

This study emphasizes the importance of regular monitoring of respiratory pathogen distribution and antimicrobial resistance patterns and the need for a comprehensive approach to managing RTIs, including implementation of antibiotic stewardship programs, infection control measures, and development of new therapies.

Diagnostic uncertainties in patients with bacteraemia: impact on antibiotic prescriptions and outcome

OBJECTIVES

To establish a formal diagnosis in infectious disease is not an easy task. Our aim was to characterize diagnostic uncertainty (DU) in patients for whom blood cultures were positive (PBC) and to determine its impact on both the antibiotic therapy and the outcome.

METHODS

This was a prospective multicentre study including PBC for 6 months. The laboratory gave the PBC result to the infectious disease (ID) specialists in real time (24/7). The latter analysed all data from electronic patient charts and gave therapeutic advice to the physicians in charge of the patient to either initiate an antibiotic therapy, or to modify or to pursue continuing antimicrobial treatment. A DU was defined as no diagnosis of ID after thorough reading of the patient's chart, or more than two diagnoses despite two medical opinions obtained before PBC. An unfavourable outcome was defined by the occurrence of death during hospitalization.

RESULTS

One hundred and nighty-nine PBCs were communicated to ID specialists, including 93 DUs (47%). In multivariate analysis, DU was associated with hospitalization in medical wards: [adjusted odds ratio (AOR) (95% CI): 6.94 (3.41-14.28)], the advice to initiate an antibiotic treatment: [3.89 (1.56-9.70)] and piperacillin-tazobactam use [3.75 (1.56-9.00)]; ICU requirement at initiation of care was a protective factor [0.38 (0.17-0.84)]. An unfavourable outcome was observed in 22 cases, and in a second logistic regression showed that DU was associated with the latter [AOR (95% CI): 5.07 (1.60-16.12)].

CONCLUSION

DUs were frequent during infections proved by PBC, and were associated with admission in medical wards, broad-spectrum antibiotic use and a high rate of unfavourable outcomes.

Evaluation of Gram Stain-Guided Antibiotic Therapy for Methicillin-Resistant Staphylococcus aureus Pneumonia in Intensive Care Unit Patients

Background: Despite high negative predictive values (NPVs) seen with methicillin-resistant Staphylococcus aureus (MRSA) nares polymerase chain reaction (PCR) assays, utilization of both respiratory sample Gram stain and MRSA nares PCR in patients with pneumonia may contribute to overuse of laboratory resources. The purpose of this study was to evaluate if a Gram stain demonstrating no Gram-positive organisms from a respiratory sample is sufficient to allow for de-escalation of vancomycin therapy. Methods: This single center study retrospectively identified intensive care unit (ICU) patients started on vancomycin for presumed pneumonia at University of Wisconsin (UW) Health in Madison, WI between August 2022 and March 2023. Patients with respiratory sample demonstrating no Gram-positives on Gram stain met inclusion criteria if the sample was ordered within 24 h of vancomycin initiation. The primary outcome was NPV of respiratory sample Gram stain demonstrating no Gram-positive organisms with respect to MRSA detection of the respiratory culture. Secondary outcomes included the NPV of combined MRSA nares PCR plus respiratory sample Gram stain, and difference in time to event in patients that had both a respiratory sample and MRSA nares PCR ordered. Results: A total of 370 patients were screened for study eligibility; of which 99 patients met inclusion criteria. NPV of respiratory sample Gram stain was 99% for MRSA culture. The combined NPV of respiratory sample Gram stain plus MRSA nares PCR was 98.9% for MRSA culture (n = 88). Respiratory sample was ordered 2.3 h faster compared to MRSA nares PCR (4.3 vs 6.6 h, P = .036). Respiratory sample Gram stain resulted 4.5 h faster compared to MRSA nares PCR (10.7 vs 15.2 h, P = .002). Conclusion: Respiratory sample Gram stains demonstrating no Gram-positive organisms may be used to de-escalate vancomycin and deprioritize the use of MRSA nares PCR.

Appropriateness of Empiric Initiation of Meropenem in the Intensive Care Unit as Determined by Internal Medicine Residents

Objective

To evaluate the appropriateness of empiric initiation of meropenem in the intensive care unit (ICU) and to determine the agreement between internal medicine (IM) residents and infectious diseases (ID) physicians/pharmacists on appropriateness.

Design

Retrospective observational study.

Setting

ICU in a tertiary care community teaching hospital.

Participants

Adult patients admitted to the ICU and started empirically on meropenem between April 1 and October 31, 2021.

Methods

Meropenem usage was categorized as appropriate or inappropriate according to criteria developed from previously published indications and modified by ID physicians/pharmacists to reflect local practices. Two investigators (an IM resident and either an ID physician or pharmacist) assessed the appropriateness, with a second ID physician resolving any disagreements. Inter-rater reliability was measured using the kappa statistic.

Results

Ninety-seven participants were enrolled, with a mean age of 68 (SD, 17.0) years. Pneumonia was the most common infection (30.9%). Among the participants, 92.8% received an ID consultation, with 55.6% of these occurring before meropenem initiation. IM residents deemed 56.7% of meropenem administrations appropriate, whereas an ID physician/pharmacist deemed only 48.5% appropriate, agreeing on 79.4% of cases (kappa statistic 0.59, P <.001). After a third reviewer's assessment was included, agreement between the resident and at least one of the two reviewers reached 90.7% (kappa 0.81, P <.001).

Conclusions

Approximately half of empiric meropenem started in the ICU was deemed inappropriate using institution-specific criteria. There was good agreement between IM residents and ID physicians/pharmacists on meropenem appropriateness. IM residents could contribute to antimicrobial stewardship efforts, like prospective audit and feedback, using standardized criteria for appropriateness.

Retrospective validation study of a machine learning-based software for empirical and organism-targeted antibiotic therapy selection

Errors in antibiotic prescriptions are frequent, often resulting from the inadequate coverage of the infection-causative microorganism. The efficacy of iAST, a machine-learning-based software offering empirical and organism-targeted antibiotic recommendations, was assessed. The study was conducted in a 12-hospital Spanish institution. After model fine-tuning with 27,531 historical antibiograms, 325 consecutive patients with acute infections were selected for retrospective validation. The primary endpoint was comparing each of the top three of iAST's antibiotic recommendations' success rates (confirmed by antibiogram results) with the antibiotic prescribed by the physicians. Secondary endpoints included examining the same hypothesis within specific study population subgroups and assessing antibiotic stewardship by comparing the percentage of antibiotics recommended that belonged to different World Health Organization AWaRe groups within each arm of the study. All of iAST first three recommendations were non-inferior to doctor prescription in the primary endpoint analysis population as well as the secondary endpoint. The overall success rate of doctors' empirical treatment was 68.93%, while that of the first three iAST options was 91.06% (P < 0.001), 90.63% (P < 0.001), and 91.06% (P < 001), respectively. For organism-targeted therapy, the doctor's overall success rate was 84.16%, and that of the first three ranked iAST options was 97.83% (P < 0.001), 94.09% (P < 0.001), and 91.30% (P < 0.001), respectively. In empirical therapy, compared to physician prescriptions, iAST demonstrated a greater propensity to recommend access antibiotics, fewer watch antibiotics, and higher reserve antibiotics. In organism-targeted therapy, iAST advised a higher utilization of access antibiotics. The present study demonstrates iAST accuracy in predicting antibiotic susceptibility, showcasing its potential to promote effective antibiotic stewardship.

CLINICAL TRIALS

This study is registered with ClinicalTrials.gov as NCT06174519.

Clinical performance of existing diagnostic criteria for pneumonia in older emergency patients: A prospective cohort study

BACKGROUND

Pneumonia accounts for over half a million older adult emergency department (ED) visits annually, but ED pneumonia diagnosis is inaccurate. Geriatric-specific pneumonia diagnostic criteria exist for other settings; no prospective data exist to determine if application in the older adult ED population is feasible. The objective was to prospectively evaluate the utility of four current diagnostic criteria (Loeb; Modified McGeer; Infectious Disease Society of America/American Thoracic Society; American College of Emergency Physicians) in older adult ED patients.

METHODS

This was a prospective, observational cohort study of older adult ED patients ≥65 years of age in two U.S. EDs with suspected pneumonia defined as having chest radiography ordered and treating physician suspicion. The standard we used for defining the presence, absence, or inability to determine a diagnosis of pneumonia diagnosis was expert physician chart adjudication. We report the summary statistics for demographic characteristics and symptoms/exam findings and sensitivity, specificity, and likelihood ratios with 95% confidence intervals of the existing diagnostic criteria. Pre-specified cutoff values of a positive LR >10 and a negative LR <0.3 were considered clinically significant.

RESULTS

Of 135 patients enrolled, 27 had pneumonia by adjudicator review. Typical patient-reported pneumonia symptoms, such as fever (18.5%) and new/worse cough (51.9%), were not consistently present in pneumonia. The IDSA/ATS and ACEP criteria had positive LR >10 and negative LR <0.3; however, all confidence intervals included pre-specified cutoffs.

CONCLUSIONS

Older adults presented to the ED with low frequency of typical pneumonia symptoms. Although existing diagnostic definitions had promising test characteristics, they may not perform well enough for clinical application without refinement.

A Single Hospital-Wide Antibiogram is Insufficient to Account for Differences in Antibiotic Resistance Patterns Across Multiple ICUs

BACKGROUND

Infection is a common cause of mortality within intensive care units (ICUs). Antibiotic resistance patterns and culture data are used to create antibiograms. Knowledge of antibiograms facilitates guiding empiric therapies and reduces mortality. Most major hospitals utilize data collection to create hospital-wide antibiograms. Previous studies have shown significant differences in susceptibility patterns between hospital wards and ICUs. We hypothesize that institutional or combined ICU antibiograms are inadequate to account for differences in susceptibility for patients in individual ICUs.

METHODS

Culture and susceptibility data were reviewed over a 1-year period for 13 bacteria in the following ICUs: Surgical/Trauma, Medical, Neuroscience, Burn, and Emergency department. Antibiotic management decisions are made by individual teams.

RESULTS

Nine species had sufficient data for inclusion into an All-ICU antibiogram. E coli and S aureus were the most common isolates. Seven species had significant differences in susceptibility patterns between ICUs. E cloacae showed higher rates of resistance to multiple antibiotics in the STICU than other ICUs. P aeruginosa susceptibility rates in the NSICU and BICU were 88% and 92%, respectively, compared to 60% and 55% in the STICU and MICU. Cephalosporins and Aztreonam had reduced efficacy against E coli in the NSICU, however remain effective in other ICUs.

CONCLUSIONS

The results of this study show that different ICUs do have variability in antibiotic susceptibility patterns within a single hospital. While this only represents a single institution, it shows that the use of hospital-wide antibiograms is inadequate for creating empiric antibiotic protocols within individual ICUs.

Toward an optimization of empirical antibiotic therapy in acute graft pyelonephritis: A retrospective multicenter study

OBJECTIVE

Acute graft pyelonephritis (AGPN) is the most frequent infectious complication in kidney transplant recipients (KTR). The treatment of acute community-acquired (CA) pyelonephritis is based on third-generation cephalosporins (3GC) and fluoroquinolones. Cefepime or a piperacillin-tazobactam combination are more often used in healthcare-associated (HCA) infections. However, these recommendations do not consider the resistance observed in KTRs. The objective of our study was to define the most appropriate empirical antibiotherapy for AGPN in KTRs according to the CA and HCA settings. To answer this question, we assessed the prevalence of resistance to different antibiotics usually recommended for urinary tract infections (UTIs) in the general population.

METHODS

Observational, retrospective, multicenter study covering all episodes of AGPN occurring in hospitalized KTRs in 2019.

RESULTS

A total of 210 patients were included in 7 centers and 244 episodes of AGPN were analyzed (158 CA-AGPN and 86 HCA-AGPN). The prevalence of 3GC and fluoroquinolone resistance was 23 % (n = 36) and 30 % (n = 50) in CA infections (n = 158), and 47 % (n = 40) and 31 % (n = 27) in HCA infections (n = 86), respectively. Cefepime resistance rate was 19 % (n = 30) in CA-AGPN and 29 % (n = 25) in HCA-AGPN. Piperacillin-tazobactam combination had resistance rates > 15 % in both CA and HCA infections. The only antimicrobials with resistance rates < 10 % were aminoglycosides and carbapenems.

CONCLUSION

None of the antibiotics recommended in empirical treatment in UTIs has shown a resistance rate of less than 10% with regard to AGPN. Therefore, none of them should be used as monotherapy. A combination therapy including amikacin could be an appropriate strategy in this setting.

Updates on Antibiotic Regimens in Acute Cholecystitis

Acute cholecystitis is one of the most common surgical diseases, which may progress from mild to severe cases. When combined with bacteremia, the mortality rate of acute cholecystitis reaches up to 10-20%. The standard of care in patients with acute cholecystitis is early laparoscopic cholecystectomy. Percutaneous cholecystostomy or endoscopic procedures are alternative treatments in selective cases. Nevertheless, antibiotic therapy plays a key role in preventing surgical complications and limiting the systemic inflammatory response, especially in patients with moderate to severe cholecystitis. Patients with acute cholecystitis have a bile bacterial colonization rate of 35-60%. The most frequently isolated microorganisms are Escherichia coli, Klebsiella spp., Streptococcus spp., Enterococcus spp., and Clostridium spp. Early empirical antimicrobial therapy along with source control of infection is the cornerstone for a successful treatment. In these cases, the choice of antibiotic must be made considering some factors (e.g., the severity of the clinical manifestations, the onset of the infection if acquired in hospital or in the community, the penetration of the drug into the bile, and any drug resistance). Furthermore, therapy must be modified based on bile cultures in cases of severe cholecystitis. Antibiotic stewardship is the key to the correct management of bile-related infections. It is necessary to be aware of the appropriate therapeutic scheme and its precise duration. The appropriate use of antibiotic agents is crucial and should be integrated into good clinical practice and standards of care.

Changes of PK/PD of Meropenem in patients with abdominal septic shock and exploration of clinical rational administration plan: a prospective exploratory study

This study aimed to explore the changes of pharmacokinetic parameters after meropenem in patients with abdominal septic shock after gastrointestinal perforation, and to simulate the probability of different dosing regimens achieving different pharmacodynamic goals. The study included 12 patients, and utilized high performance liquid chromatography-tandem mass spectrometry to monitor the plasma concentration of meropenem. The probability of target attainment (PTA) for different minimum inhibitory concentration (MIC) values and %fT > 4MIC was compared among simulated dosing regimens. The results showed that in 96 blood samples from 12 patients, the clearance (CL) of meropenem in the normal and abnormal creatinine clearance subgroups were 7.7 ± 1.8 and 4.4 ± 1.1 L/h, respectively, and the apparent volume of distribution (Vd) was 22.6 ± 5.1 and 17.2 ± 5.8 L, respectively. 2. Regardless of the subgroup, 0.5 g/q6h infusion over 6 h regimen achieved a PTA > 90% when MIC ≤ 0.5 mg/L. 1.0 g/q6h infusion regimen compared with other regimen, in most cases, the probability of making PTA > 90% is higher. For patients at low MIC, 0.5 g/q6h infusion over 6 h may be preferable. For patients at high MIC, a dose regimen of 1.0 g/q6 h infusion over 6 h may be preferable. Further research is needed to confirm this exploratory result.

Severe Community-Acquired Pneumonia in Immunocompromised Patients

Due to higher survival rates with good quality of life, related to new treatments in the fields of oncology, hematology, and transplantation, the number of immunocompromised patients is increasing. But these patients are at high risk of intensive care unit admission because of numerous complications. Acute respiratory failure due to severe community-acquired pneumonia is one of the leading causes of admission. In this setting, the need for invasive mechanical ventilation is up to 60%, associated with a high hospital mortality rate of around 40 to 50%. A wide range of pathogens according to the reason of immunosuppression is associated with severe pneumonia in those patients: documented bacterial pneumonia represents a third of cases, viral and fungal pneumonia both account for up to 15% of cases. For patients with an undetermined etiology despite comprehensive diagnostic workup, the hospital mortality rate is very high. Thus, a standardized diagnosis strategy should be defined to increase the diagnosis rate and prescribe the appropriate treatment. This review focuses on the benefit-to-risk ratio of invasive or noninvasive strategies, in the era of omics, for the management of critically ill immunocompromised patients with severe pneumonia in terms of diagnosis and oxygenation.

Is Zero Ventilator-Associated Pneumonia Achievable? Updated Practical Approaches to Ventilator-Associated Pneumonia Prevention

Ventilator-associated pneumonia (VAP) remains a significant clinical entity with reported incidence rates of 7% to 15%. Given the considerable adverse consequences associated with this infection, VAP prevention became a core measure required in most US hospitals. Many institutions took pride in implementing effective VAP prevention bundles that combined at least head of bed elevation, hand hygiene, chlorhexidine oral care, and subglottic drainage. Spontaneous breathing and awakening trials have also consistently been shown to shorten the duration of mechanical ventilation and secondarily reduce the occurrence of VAP.

Rapid determination of antimicrobial susceptibility of Gram-negative bacteria from clinical blood cultures using a scattered light-integrated collection device

Background. A bloodstream infection (BSI) presents a complex and serious health problem, a problem that is being exacerbated by increasing antimicrobial resistance (AMR).Gap Statement. The current turnaround times (TATs) for most antimicrobial susceptibility testing (AST) methods offer results retrospective of treatment decisions, and this limits the impact AST can have on antibiotic prescribing and patient care. Progress must be made towards rapid BSI diagnosis and AST to improve antimicrobial stewardship and reduce preventable deaths from BSIs. To support the successful implementation of rapid AST (rAST) in hospital settings, a rAST method that is affordable, is sustainable and offers comprehensive AMR detection is needed.Aim. To evaluate a scattered light-integrated collection (SLIC) device against standard of care (SOC) to determine whether SLIC could accelerate the current TATs with actionable, accurate rAST results for Gram-negative BSIs.Methods. Positive blood cultures from a tertiary referral hospital were studied prospectively. Flagged positive Gram-negative blood cultures were confirmed by Gram staining and analysed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, Vitek 2, disc diffusion (ceftriaxone susceptibility only) and an SLIC device. Susceptibility to a panel of five antibiotics, as defined by European Committee on Antimicrobial Susceptibility Testing breakpoints, was examined using SLIC.Results. A total of 505 bacterial-antimicrobial combinations were analysed. A categorical agreement of 95.5 % (482/505) was achieved between SLIC and SOC. The 23 discrepancies that occurred were further investigated by the broth microdilution method, with 10 AST results in agreement with SLIC and 13 in agreement with SOC. The mean time for AST was 10.53±0.46 h and 1.94±0.02 h for Vitek 2 and SLIC, respectively. SLIC saved 23.96±1.47 h from positive blood culture to AST result.Conclusion. SLIC has the capacity to provide accurate AST 1 day earlier from flagged positive blood cultures than SOC. This significant time saving could accelerate time to optimal antimicrobial therapy, improving antimicrobial stewardship and management of BSIs.

Efficiency of dosing software using Bayesian forecasting in achieving target antibiotic exposures in critically ill patients, a prospective cohort study

INTRODUCTION

Broad-spectrum antibiotics such as beta-lactams and vancomycin are frequently used to treat critically ill patients, however, a significant number do not achieve target exposures. Therapeutic drug monitoring (TDM) combined with Bayesian forecasting dosing software may improve target attainment in these patients. This study aims to describe the efficiency of dosing software for achieving target exposures of selected beta-lactam antibiotics and vancomycin in critically ill patients.

METHODS

A prospective cohort study was undertaken in an adult intensive care unit (ICU). Patients prescribed vancomycin, piperacillin-tazobactam and meropenem were included if they exhibited a subtherapeutic or supratherapeutic exposure informed by TDM. The dosing software, ID-ODS™, was used to generate dosing recommendations which could be either accepted or rejected by the treating team. Repeat antibiotic TDM were requested to determine if target exposures were achieved.

RESULTS

Between March 2020 and December 2021, 70 were included in the analysis. Software recommendations were accepted for 56 patients (80%) with 50 having repeated antibiotic measurements. Forty-three of the 50 patients (86%) achieved target exposures after one software recommendation, with 3 of the remaining 7 patients achieving target exposures after 2. Forty-seven patients out of the 50 patients (94%) achieved the secondary outcome of clinical cure. There were no antibiotic exposure-related adverse events reported.

CONCLUSION

The use of TDM combined with Bayesian forecasting dosing software increases the efficiency for achieving target antibiotic exposures in the ICU. Clinical trials comparing this approach with other dosing strategies are required to further validate these findings.

Predictors of unfavourable outcome in adults with suspected central nervous system infections: a prospective cohort study

Suspected central nervous system (CNS) infections may pose a diagnostic challenge, and often concern severely ill patients. We aim to identify predictors of unfavourable outcome to prioritize diagnostics and treatment improvements. Unfavourable outcome was assessed on the Glasgow Outcome Scale at hospital discharge, defined by a score of 1 to 4. Of the 1152 episodes with suspected CNS infection, from two Dutch prospective cohorts, the median age was 54 (IQR 37-67), and 563 episodes (49%) occurred in women. The final diagnoses were categorized as CNS infection (N = 358 episodes, 31%), CNS inflammatory disease (N = 113, 10%), non-infectious non-inflammatory neurological disorder (N = 388, 34%), non-neurological infection (N = 252, 22%), and other systemic disorder (N = 41, 4%). Unfavourable outcome occurred in 412 of 1152 (36%), and 99 died (9%). Predictors for unfavourable outcomes included advanced age, absence of headache, tachycardia, altered mental state, focal cerebral deficits, cranial nerve palsies, low thrombocytes, high CSF protein, and the final diagnosis of CNS inflammatory disease (odds ratio 4.5 [95% confidence interval 1.5-12.6]). Episodes suspected of having a CNS infection face high risk of experiencing unfavourable outcome, stressing the urgent need for rapid and accurate diagnostics. Amongst the suspected CNS infection group, those diagnosed with CNS inflammatory disease have the highest risk.

Towards optimization of ceftazidime dosing in obese ICU patients: the end of the 'one-size-fits-all' approach?

BACKGROUND

Ceftazidime is commonly used as a key antibiotic against Pseudomonas aeruginosa in critically ill patients. ICU patients have severely altered and variable antibiotic pharmacokinetics, resulting in lower antimicrobial concentrations and potentially poor outcome. Several factors, including obesity and renal function, may influence pharmacokinetics. Thus, the objective of the study was to evaluate the impact of obesity and renal function on ceftazidime plasma concentrations and dosing regimen in ICU patients.

METHODS

All consecutive adult patients from six ICUs, treated with continuous ceftazidime infusion and under therapeutic drug monitoring evaluation, were included. Obesity was defined as BMI ≥30 kg/m². Glomerular filtration rate (GFR) was estimated by the Chronic Kidney Disease Epidemiology Collaboration formula. The ceftazidime recommended target for plasma concentrations was between 35 and 80 mg/L.

RESULTS

A total of 98 patients (45 obese), with an average weight of 90 (±25) kg, were included. Mean GFR was 84.1 (±40.4) mL/min/1.73 m2. Recommended ceftazidime plasma concentrations were achieved for only 48.0% of patients, with median dosing regimen of 6 g/day. Obese patients had lower ceftazidime plasma concentrations compared with non-obese patients (37.8 versus 56.3 mg/L; P = 0.0042) despite similar dosing regimens (5.83 g/day versus 5.52 g/day, P = 0.2529). Almost all augmented renal clearance patients were underdosed despite ceftazidime dosing of 6.6 (±0.8) g/day. Weight-based ceftazidime dosing seemed to attenuate such obesity-related discrepancies, regardless of GFR.

CONCLUSIONS

Obese ICU patients required significantly greater ceftazidime doses to achieve the target range. A tailored dosing regimen may be considered based on weight and GFR. Future prospective studies should be performed to confirm this individualized dosing approach.

Emergency department patient and physician survey accuracy compared to chart abstraction in patients with acute respiratory illness

BACKGROUND

High-quality research studies in older adults are needed. Unfortunately, the accuracy of chart review data in older adult patients has been called into question by previous studies. Little is known on this topic in patients with suspected pneumonia, a disease with 500,000 annual older adult U.S. emergency department (ED) visits that presents a diagnostic challenge to ED physicians. The study objective was to compare direct interview and chart abstraction as data sources.

METHODS

We present a preplanned secondary analysis of a prospective, observational cohort of ED patients ≥65 years of age with suspected pneumonia in two Midwest EDs. We describe the agreement between chart review and a criterion standard of prospective direct patient survey (symptoms) or direct physician survey (examination findings). Data were collected by chart review and from the patient and treating physician by survey.

RESULTS

The larger study enrolled 135 older adults; 134 with complete symptom data and 129 with complete examination data were included in this analysis. Pneumonia symptoms (confusion, malaise, rapid breathing, any cough, new/worse cough, any sputum production, change to sputum) had agreement between patient/legally authorized representative survey and chart review ranging from 47.8% (malaise) to 80.6% (confusion). All examination findings (rales, rhonchi, wheeze) had percent agreement between physician survey and chart review of ≥80%. However, all kappas except wheezing were less than 0.60, indicating weak agreement.

CONCLUSIONS

Both patient symptoms and examination findings demonstrated discrepancies between chart review and direct survey with larger discrepancies in symptoms reported. Researchers should consider these potential discrepancies during study design and data interpretation.

Performance evaluation of a PCR panel (FilmArray® Pneumonia Plus) for detection of respiratory bacterial pathogens in respiratory specimens: A systematic review and meta-analysis

BACKGROUND

Accuracy and timing of antibiotic therapy remain a challenge for lower respiratory tract infections. New molecular techniques using Multiplex Polymerase Chain Reaction, including the FilmArray® Pneumonia Plus Panel [FAPP], have been developed to address this. The aim of this study is to evaluate the FAPP diagnostic performance for the detection of the 15 typical bacteria of the panel from respiratory samples in a meta-analysis from a systematic review.

METHODS

We searched PubMed and EMBASE from January 1, 2010, to December 31, 2022, and selected any study on the FAPP diagnostic performance on respiratory samples compared to the reference standard, bacterial culture. The main outcome was the overall diagnostic accuracy with sensitivity and specificity. We calculated the log Diagnostic Odds Ratio and analyzed performance for separate bacteria, antimicrobial resistance genes, and according to the sample type. We also reported the FAPP turnaround time and the out-of-panel bacteria number and species. This study is registered with PROSPERO (CRD42021226280).

RESULTS

From 10 317 records, we identified 30 studies including 8 968 samples. Twenty-one were related to intensive care. The overall sensitivity and specificity were 94% [95% Confidence Interval (CI) 91-95] and 98% [95%CI 97-98], respectively. The log Diagnostic Odds Ratio was 6.35 [95%CI 6.05-6.65]. 9.3% [95%CI 9.2-9.5] of bacteria detected in culture were not included in the FAPP panel.

CONCLUSION

This systematic review reporting the FAPP evaluation revealed a high accuracy. This test may represent an adjunct tool for pulmonary bacterial infection diagnostic and antimicrobial stewardship. Further evidence is needed to assess the impact on clinical outcome.

Identification of a marker of infection in the breath using a porcine pneumonia model

Objective

Pneumonia, both in the community and the hospital setting, represents a significant cause of morbidity and mortality in the cardiothoracic patient population. Diagnosis of pneumonia can be masked by other disease processes and is often diagnosed after the patient is already experiencing the disease. A noninvasive, sensitive test for pneumonia could decrease hospitalizations and length of stay for patients. We have developed a porcine model of pneumonia and evaluated the exhaled breath of infected pigs for biomarkers of infection.

Methods

Anesthetized 60-kg adult pigs were intubated, and a bronchoscope was used to instill a solution containing 12 × 108 cfu of methicillin-sensitive Staphylococcus aureus or a control solution without bacteria (Sham) into the distal airways. The pigs were then reintubated on postoperative days 3, 6, and 9, with bronchoscopic bronchial lavages taken at each time point. At each time point, a 500-mL breath was captured from each pig. The breath was evacuated over a silicon microchip, with the volatile carbonyl compounds from the breath captured via oximation reaction, and the results of this capture were analyzed by ultra-high performance liquid chromatography mass spectrometry.

Results

A total of 64% of the pigs inoculated with methicillin-sensitive S. aureus demonstrated consolidation on chest radiography and increasing counts of methicillin-sensitive S. aureus in the bronchial lavages over the span of the experiment, consistent with development of pneumonia. Analysis of the exhaled breath demonstrated 1 carbonyl compound (2-pentenal) that increased 10-fold over the span of the experiment, from an average of 0.0294 nmol/L before infection to an average of 0.3836 nmol/L on postoperative day 9. The amount of 2-pentenal present was greater in the breath of infected pigs than in the noninfected pigs or the sham inoculated pigs at postoperative days 6 and 9. Using an elevated concentration of 2-pentenal as a marker of infection yielded a sensitivity of 88% and specificity of 92% at postoperative day 6, and a sensitivity and specificity of 100% at postoperative day 9.

Conclusions

We were able to successfully develop a clinical pneumonia in adult 60-kg pigs. The concentration of 2-pentenal correlated with the presence of pneumonia, demonstrating the potential for this compound to function as a biomarker for methicillin-sensitive S. aureus infection in pigs.

Lacosamide dosing in patients receiving continuous renal replacement therapy

BACKGROUND

Lacosamide is one of the anticonvulsants used in critically ill patients. This study aimed to suggest appropriate lacosamide dosing regimens in critically ill patients receiving continuous renal replacement therapy (CRRT) via Monte Carlo simulations.

METHODS

Mathematical models were created using published demographic and pharmacokinetics in adult critically ill patients. CRRT modalities with different effluent rates were added into the models. Lacosamide regimens were evaluated on the probability of target attainment (PTA) using pharmacodynamic targets of trough concentrations and area under the curve within a range of 5-10 mg/L and 80.25-143 and 143-231 mg*h/L for the initial 72 h-therapy, respectively. Optimal regimens were defined from regimens that yielded the highest PTA. Each dosing regimen was tested in a group of different 10,000 virtual patients.

RESULTS

Our results revealed the optimal lacosamide dosing regimen of 300-450 mg/day is recommended for adult patients receiving both CRRT modalities with 20-25 effluent rates. The dose of 600 mg/day was suggested in higher effluent rate of 35 mL/kg/h. Moreover, a patient with body weight > 100 kg was less likely to attain the targets.

CONCLUSIONS

Volume of distribution, total clearance, CRRT clearance and body weight were significantly contributed to lacosamide dosing. Clinical validation of the finding is strongly indicated.

Efficacy of therapeutic drug monitoring-based antibiotic regimen in critically ill patients: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

The efficacy of therapeutic drug monitoring (TDM)-based antimicrobial dosing optimization strategies on pharmacokinetics/pharmacodynamics and specific drug properties for critically ill patients is unclear. Here, we conducted a systematic review and meta-analysis of randomized controlled trials to evaluate the effectiveness of TDM-based regimen in these patients.

METHODS

Articles from three databases were systematically retrieved to identify relevant randomized control studies. Version two of the Cochrane tool for assessing risk of bias in randomized trials was used to assess the risk of bias in studies included in the analysis, and quality assessment of evidence was graded using the Grading of Recommendations Assessment, Development, and Evaluation approach. Primary outcome was the 28-day mortality and secondary outcome were in-hospital mortality, clinical cure, length of stay in the intensive care unit (ICU) and target attainment at day 1 and 3.

RESULTS

In total, 5 studies involving 1011 patients were included for meta-analysis of the primary outcome, of which no significant difference was observed between TDM-based regimen and control groups (risk ratio [RR] 0.94, 95% confidence interval [CI]: 0.77-1.14; I2 = 0%). In-hospital mortality (RR 0.96, 95% CI: 0.76-1.20), clinical cure (RR 1.23, 95% CI: 0.91-1.67), length of stay in the ICU (mean difference 0, 95% CI: - 2.18-2.19), and target attainment at day 1 (RR 1.14, 95% CI: 0.88-1.48) and day 3 (RR 1.35, 95% CI: 0.90-2.03) were not significantly different between the two groups, and all evidence for the secondary outcomes had a low or very low level of certainty because the included studies had serious risk of bias, variation of definition for outcomes, and small sample sizes.

CONCLUSION

TDM-based regimens had no significant efficacy for clinical or pharmacological outcomes. Further studies with other achievable targets and well-defined outcomes are required.

TRIAL REGISTRATION

Clinical trial registration; PROSPERO ( https://www.crd.york.ac.uk/prospero/ ), registry number: CRD 42022371959. Registered 24 November 2022.

biomArker-guided Duration of Antibiotic treatment in hospitalised Patients with suspecTed Sepsis (ADAPT-Sepsis): A protocol for a multicentre randomised controlled trial

Aim

To describe the protocol for a multi-centre randomised controlled trial to determine whether treatment protocols monitoring daily CRP (C-reactive protein) or PCT (procalcitonin) safely allow a reduction in duration of antibiotic therapy in hospitalised adult patients with sepsis.

Design

Multicentre three-arm randomised controlled trial.

Setting

UK NHS hospitals.

Target population

Hospitalised critically ill adults who have been commenced on intravenous antibiotics for sepsis.

Health technology

Three protocols for guiding antibiotic discontinuation will be compared: (a) standard care; (b) standard care + daily CRP monitoring; (c) standard care + daily PCT monitoring. Standard care will be based on routine sepsis management and antibiotic stewardship. Measurement of outcomes and costs. Outcomes will be assessed to 28 days. The primary outcomes are total duration of antibiotics and safety outcome of all-cause mortality. Secondary outcomes include: escalation of care/re-admission; infection re-lapse/recurrence; antibiotic dose; length and level of critical care stay and length of hospital stay. Ninety-day all-cause mortality rates will also be collected. An assessment of cost effectiveness will be performed.

Conclusion

In the setting of routine NHS care, if this trial finds that a treatment protocol based on monitoring CRP or PCT safely allows a reduction in duration of antibiotic therapy, and is cost effective, then this has the potential to change clinical practice for critically ill patients with sepsis. Moreover, if a biomarker-guided protocol is not found to be effective, then it will be important to avoid its use in sepsis and prevent ineffective technology becoming widely adopted in clinical practice.

Assessing the Utility of Multiplexed Polymerase Chain Reaction in Detecting Microorganisms Causing Infections in Critically ill Patients

Early sepsis diagnosis is crucial for implementing adequate antibiotic therapy and for patient survival. This study investigated whether using multiplexed PCR for detecting microorganisms in critical septic patients affects initial antibiotic treatment and compared it to microbiological culture. It also explored scenarios where PCR is more effective in clinical practice. One hundred nineteen specimens (83 blood and 36 respiratory specimens) belonging to 93 patients were analyzed. Multiplexed PCR determinations were performed using the FA-BCID Panel (bioMérieux) for blood samples and the FA-Pneumo for respiratory samples. The mean turnaround times were 1.7 h for the FA-BCID and 1.5h for the FA-Pneumo. Conversely, they were 96.1 h for blood cultures and 72.3 h for respiratory cultures. FA-BCID showed a mean sensitivity of 97% and specificity of 100%. FA-Pneumo showed a sensitivity of 100% and specificity of 90%. However, the positive predictive value was only 39%. Discrepancies were common in polymicrobial samples. Based on the PCR results, initial empirical treatment should have been changed in 71% of patients with bloodstream infections and 61% with respiratory infections. We conclude that multiplexed PCR improves the response time in identifying germs with a high degree of coincidence for blood cultures and moderate for respiratory cultures. These results highlight the importance of PCR in choosing an appropriate antibiotic therapy.

Aetiological agents of adult community-acquired pneumonia in Japan: systematic review and meta-analysis of published data

OBJECTIVE

Epidemiological information is essential in providing appropriate empiric antimicrobial therapy for pneumonia. This study aimed to clarify the epidemiology of community-acquired pneumonia (CAP) by conducting a systematic review of published studies in Japan.

DESIGN

Systematic review.

DATA SOURCE

PubMed and Ichushi web database (January 1970 to October 2022).

ELIGIBILITY CRITERIA

Clinical studies describing pathogenic micro-organisms in CAP written in English or Japanese, excluding studies on pneumonia other than adult CAP, investigations limited to specific pathogens and case reports.

DATA EXTRACTION AND SYNTHESIS

Patient setting (inpatient vs outpatient), number of patients, concordance with the CAP guidelines, diagnostic criteria and methods for diagnosing pneumonia pathogens as well as the numbers of each isolate. A meta-analysis of various situations was performed to measure the frequency of each aetiological agent.

RESULTS

Fifty-six studies were included and 17 095 cases of CAP were identified. Pathogens were undetectable in 44.1% (95% CI 39.7% to 48.5%). Streptococcus pneumoniae was the most common cause of CAP requiring hospitalisation or outpatient care (20.0% (95% CI 17.2% to 22.8%)), followed by Haemophilus influenzae (10.8% (95% CI 7.3% to 14.3%)) and Mycoplasma pneumoniae (7.5% (95% CI 4.6% to 10.4%)). However, when limited to CAP requiring hospitalisation, Staphylococcus aureus was the third most common at 4.9% (95% CI 3.9% to 5.8%). Pseudomonas aeruginosa was more frequent in hospitalised cases, while atypical pathogens were less common. Methicillin-resistant S. aureus accounted for 40.7% (95% CI 29.0% to 52.4%) of S. aureus cases. In studies that used PCR testing for pan-respiratory viral pathogens, human enterovirus/human rhinovirus (9.4% (95% CI 0% to 20.5%)) and several other respiratory pathogenic viruses were detected. The epidemiology varied depending on the methodology and situation.

CONCLUSION

The epidemiology of CAP varies depending on the situation, such as in the hospital versus outpatient setting. Viruses are more frequently detected by exhaustive genetic searches, resulting in a significant variation in epidemiology.

Applicability and limitations of quality indicator-based assessment of appropriateness in antimicrobial use: a comparison with expert opinion

BACKGROUND

The effective implementation of antimicrobial stewardship requires an a-priori assessment of the appropriateness of antimicrobial prescriptions.

AIM

To evaluate the effectiveness of quality indicators (QIs) in determining the appropriateness of antimicrobial prescriptions compared to that of expert opinions.

METHODS

The study assessed antimicrobial use in 20 hospitals in Korea, with infectious disease specialists rating the appropriateness based on QIs and expert opinions. The selected QIs were (1) taking two blood cultures, (2) taking cultures from suspected sites of infection, (3) prescribing empirical antimicrobials according to guidelines, and (4) changing from empirical to pathogen-directed therapy for hospitalized patients and (2, 3, and 4) for ambulatory patients. Applicability, compliance with QIs, and agreement between QIs and expert opinions were investigated.

FINDINGS

Overall, 7999 therapeutic uses of antimicrobials were investigated at the study hospitals. The experts rated 20.5% (1636/7999) as inappropriate use. For hospitalized patients, antimicrobial use was assessed based on all four QIs in 28.8% (1798/6234) of the cases. For ambulatory care patients, only 7.5% (102/1351) of the antimicrobial use cases were assessed using all three QIs. The agreement between expert opinions and all four QIs for hospitalized patients was minimal (κ = 0.332), whereas that between expert opinions and all three QIs for ambulatory patients was weak (κ = 0.598).

CONCLUSION

QIs have limitations in determining the appropriateness of antimicrobial use, and the degree of agreement with expert opinions was low. Therefore, these QI limitations should be considered when determining the appropriateness of antimicrobial use.

Impact of empiric antibiotic therapy on the clinical outcome of acute calculous cholecystitis

PURPOSE

Although mortality and morbidity of severe acute calculous cholecystitis (ACC) are still a matter of concern, the impact of inadequate empirical antibiotic therapy has been poorly studied as a risk factor. The objective was to assess the impact of the adequacy of empirical antibiotic therapy on complication and mortality rates in ACC.

METHODS

This observational retrospective cohort chart-based single-center study was conducted between 2012 and 2016. A total of 963 consecutive patients were included, and pure ACC was selected. General, clinical, postoperative, and microbiological variables were collected, and risk factors and consequences of inadequate treatment were analyzed.

RESULTS

Bile, blood, and/or exudate cultures were obtained in 76.3% of patients, more often in old, male, and severely ill patients (P < 0.001). Patients who were cultured had a higher overall rate of postoperative complications (47.4% vs. 29.7%; P < 0.001), as well as of severe complications (11.6% vs. 4.7%; P = 0.008). Patients with positive cultures had more overall complications (54.8% vs. 39.6%; P = 0.001), more severe complications (16.3% vs. 6.7%; P = 0.001), and higher mortality rates (6% vs. 1.9%; P = 0.012). Patients who received inadequate empirical antibiotic therapy had a fourfold higher mortality rate than those receiving adequate therapy (n = 283; 12.8% vs. 3.4%; P = 0.003). This association was especially marked in severe ACC TG-III patients (n = 132; 18.2 vs. 5.1%; P = 0.018) and remained a predictor of mortality in a binary logistic regression (OR 4.4; 95% CI 1.3-15.3).

CONCLUSION

Patients with positive cultures developed more complications and faced higher mortality. Adequate empirical antibiotic therapy appears to be of paramount importance in ACC, particularly in severely ill patients.

Evaluating the Translational Potential of Bacteriocins as an Alternative Treatment for Staphylococcus aureus Infections in Animals and Humans

Antibiotic resistance remains a global threat to human and animal health. Staphylococcus aureus is an opportunistic pathogen that causes minor to life-threatening infections. The widespread use of antibiotics in the clinical, veterinary, and agricultural setting combined with the increasing prevalence of antibiotic-resistant S. aureus strains makes it abundantly clear that alternatives to antibiotics are urgently needed. Bacteriocins represent one potential alternative therapeutic. They are antimicrobial peptides that are produced by bacteria that are generally nontoxic and have a relatively narrow target spectrum, and they leave many commensals and most mammalian cells unperturbed. Multiple studies involving bacteriocins (e.g., nisin, epidermicin, mersacidin, and lysostaphin) have demonstrated their efficacy at eliminating or treating a wide variety of S. aureus infections in animal models. This review provides a comprehensive and updated evaluation of animal studies involving bacteriocins and highlights their translational potential. The strengths and limitations associated with bacteriocin treatments compared with traditional antibiotic therapies are evaluated, and the challenges that are involved with implementing novel therapeutics are discussed.

A random forest model using flow cytometry data identifies pulmonary infection after thoracic injury

BACKGROUND

Thoracic injury can cause impairment of lung function leading to respiratory complications such as pneumonia (PNA). There is increasing evidence that central memory T cells of the adaptive immune system play a key role in pulmonary immunity. We sought to explore whether assessment of cell phenotypes using flow cytometry (FCM) could be used to identify pulmonary infection after thoracic trauma.

METHODS

We prospectively studied trauma patients with thoracic injuries who survived >48 hours at a Level 1 trauma center from 2014 to 2020. Clinical and FCM data from serum samples collected within 24 hours of admission were considered as potential variables. Random forest and logistic regression models were developed to estimate the risk of hospital-acquired and ventilator-associated PNA. Variables were selected using backwards elimination, and models were internally validated with leave-one-out.

RESULTS

Seventy patients with thoracic injuries were included (median age, 35 years [interquartile range (IQR), 25.25-51 years]; 62.9% [44 of 70] male, 61.4% [42 of 70] blunt trauma). The most common injuries included rib fractures (52 of 70 [74.3%]) and pulmonary contusions (26 of 70 [37%]). The incidence of PNA was 14 of 70 (20%). Median Injury Severity Score was similar for patients with and without PNA (30.5 [IQR, 22.6-39.3] vs. 26.5 [IQR, 21.6-33.3]). The final random forest model selected three variables (Acute Physiology and Chronic Health Evaluation score, highest pulse rate in first 24 hours, and frequency of CD4 + central memory cells) that identified PNA with an area under the curve of 0.93, sensitivity of 0.91, and specificity of 0.88. A logistic regression with the same features had an area under the curve of 0.86, sensitivity of 0.76, and specificity of 0.85.

CONCLUSION

Clinical and FCM data have diagnostic utility in the early identification of patients at risk of nosocomial PNA following thoracic injury. Signs of physiologic stress and lower frequency of central memory cells appear to be associated with higher rates of PNA after thoracic trauma.

LEVEL OF EVIDENCE

Diagnostic Test/Criteria; Level IV.

Evaluation of the meropenem dosage and administration schedule in patients with bacteremia initial therapy

BACKGROUND

The standard meropenem (MEPM) regimen allowed by insurance in Japan is 0.5 g two or three times a day. Differences in dosages and administration schedules in Japan were evaluated.

METHODS

Patients with bacteremia for whom MEPM was used as the initial treatment at our institution between 2016 and 2021 were included. We retrospectively investigated patients classified into two groups: those treated according to severe infections (high-dose groupand others (low-dose group). After propensity score matching, we compared the probability of achieving free drug blood levels above the minimum inhibitory concentration (MIC) in 24 h (%fT > MIC) and outcomes.

RESULTS

The probability of 100% fT > MIC was significantly higher in the high-dose group (96.4% vs 74.5%, odds ratio [OR] = 0.3, 95% confidence interval [CI] = 0.2-0.4, P = < 0.001). Regarding outcomes, the 30-day mortality rate was significantly lower in the high-dose group (1.4% vs. 11.4%, OR = 8.0, 95% CI = 1.5-43.7, P = 0.019).

CONCLUSIONS

To improve outcomes in patients with bacteremia treated with MEPM, support for appropriate antimicrobial use is necessary for compliance with the dosage and administration schedule according to severe infections in initial treatment.

Pseudomonas Bacteremia in Children: Clinical and Microbiologic Features and Risk Factors of Mortality: A Retrospective Cohort Study

BACKGROUND

Pseudomonas bacteremia is most commonly acquired in hospital. The aim of this study was to investigate the clinical features and antibiotic susceptibility, mortality rate and risk factors of mortality in children with Pseudomonas bacteremia.

METHODS

A retrospective cohort study that included children 18 years of age or younger admitted to a tertiary hospital with Pseudomonas bacteremia between 2005 and 2020.

RESULTS

A total of 196 patients with Pseudomonas bacteremia were identified. The proportional rate of Pseudomonas bacteremia was 33.9/100,000 hospital days. Underlying disease was documented in 81.1% of patients, 61% had hemato-oncological disease. Pseudomonas bacteremia was healthcare related in 180 (91.8%) episodes. Multidrug-resistant (MDR) Pseudomonas accounted for 16 (8.2%) and difficult-to-treat organism to 3 (1.5%) of all isolates. Thirty-day mortality was reported in 27 (13.8%) patients, all had Pseudomonas aeruginosa. In multivariate regression analysis, the first model showed that younger age [P = 0.038, odds ratio (OR) = 1.095, 95% confidence interval (CI): 1.005-1.192] and inappropriate empiric antibiotic treatment (P = 0.004, OR = 3.584, 95% CI: 1.490-8.621) were significantly associated with higher mortality. The second model also showed higher morality in younger age (P = 0.021, OR = 1.114, 95% CI: 1.016-1.221) and MDR isolates (P = 0.001, OR = 9.725, 95% CI: 2.486-38.039).

CONCLUSIONS

Significant morbidity and mortality due to Pseudomonas bacteremia, but relatively lower mortality than previously published. Although young age, MDR isolates and inappropriate antibiotic treatment have been associated with increased mortality, these factors, especially with low prevalence of MDR isolates, may reflect the baseline mortality rate in vulnerable hosts with continuous contact with healthcare facilities facing such severe infection, and more efforts should be made to emphasize infection control practices to prevent such severe infection.

Performance of the Vitek 2 Advanced Expert System (AES) as a Rapid Tool for Reporting Antimicrobial Susceptibility Testing (AST) in Enterobacterales from North and Latin America

This study evaluated the performance of the Vitek 2 Advanced Expert System (AES) confidence level report as a rapid tool for reporting antimicrobial susceptibility testing (AST) results for a challenging set of Enterobacterales isolates from North and Latin America. Enterobacterales isolates (n = 513) were tested by CLSI broth microdilution (BMD) and Vitek 2 (N802 and XN15 AST cards). Wild-type isolates and isolates harboring acquired β-lactamases by whole-genome sequencing were included. The AES assessment of confidence level (green, yellow, and red reports) was compared to BMD results and known genotypes and reviewed by a microbiologist for accuracy. Totals of 148 (28.8%) wild-type isolates and 365 (71.2%) Enterobacterales isolates harboring carbapenemase (211 [41.1%]), extended-spectrum β-lactamase (ESBL) (122 [23.8%]), and/or transferrable AmpC (tAmpC) (32 [6.2%]) genes were evaluated. The AES confidence level was assessed for 488 isolates, and a phenotype was recognized for 447 (91.6%) isolates. Green, yellow, and red AES reports were noted for 382 (78.3%), 65 (13.3%), and 41 (8.4%) isolates, respectively. Compared to BMD, 96.3% of green AES reports could be confidently and rapidly auto-released, enabling rapid adjustments to antimicrobial therapy. In addition, 69.2% of yellow reports were acceptable, and recommendations to address current AES limitations were made. IMPORTANCE Antimicrobial susceptibility testing (AST) reports are one of the most important clinical microbiology laboratory tasks. AST reports are essential to drive antimicrobial therapy, provide information to monitor antimicrobial resistance rates, and trigger further tests to detect outbreaks or confirm new mechanisms of resistance. Commercial AST devices are frequently used to generate AST reports, and an advanced expert system (AES), such as the Vitek 2 AES, incorporates extensive knowledge to recognize certain susceptibility patterns as indicative of specific phenotypes. Moreover, the Vitek 2 AES also provides a level of confidence for auto-releasing the reports. In this study, the performance of the Vitek 2 AES was compared to state-of-the-art methodologies for AST, broth microdilution and β-lactamase gene detection, whole-genome sequencing, against a collection of 513 Enterobacterales clinical isolates harboring various β-lactamase genes, including carbapenemase, ESBL, and transferrable AmpC genes, from 73 medical centers in 7 countries in North and Latin America.

Sequestration of Antimicrobial Agents in Xcoating and Heparin-Coated Extracorporeal Membrane Oxygenation Circuits: An In Vitro Study

Limited data exist to guide antimicrobial therapy commonly prescribed to patients undergoing extracorporeal membrane oxygenation (ECMO). This study aimed to describe the kinetics of the cefazolin, doripenem, daptomycin, and levofloxacin in heparin-coated and Xcoating ECMO circuits. Circuits were primed with bovine whole blood and maintained at a physiological pH and temperature for 24 h. Each antimicrobial agent was added to the whole blood before priming. Equivalent doses of these drugs were added to glass jars containing fresh bovine whole blood as a control. Serial blood samples were collected from the ECMO circuits and controls over 24 h, and drug concentrations were quantified using validated assays. The concentrations of cefazolin, doripenem, daptomycin, and levofloxacin did not decrease significantly over 24 h. Collectively, these antimicrobial agents can be administered without the need to consider sequestration when using either heparin-coated or Xcoating circuits.

The threat of multidrug-resistant/extensively drug-resistant Gram-negative respiratory infections: another pandemic

Antibiotic resistance is recognised as a global threat to human health by national healthcare agencies, governments and medical societies, as well as the World Health Organization. Increasing resistance to available antimicrobial agents is of concern for bacterial, fungal, viral and parasitic pathogens. One of the greatest concerns is the continuing escalation of antimicrobial resistance among Gram-negative bacteria resulting in the endemic presence of multidrug-resistant (MDR) and extremely drug-resistant (XDR) pathogens. This concern is heightened by the identification of such MDR/XDR Gram-negative bacteria in water and food sources, as colonisers of the intestine and other locations in both hospitalised patients and individuals in the community, and as agents of all types of infections. Pneumonia and other types of respiratory infections are among the most common infections caused by MDR/XDR Gram-negative bacteria and are associated with high rates of mortality. Future concerns are already heightened due to emergence of resistance to all existing antimicrobial agents developed in the past decade to treat MDR/XDR Gram-negative bacteria and a scarcity of novel agents in the developmental pipeline. This clinical scenario increases the likelihood of a future pandemic caused by MDR/XDR Gram-negative bacteria.

Descriptive epidemiology of hospitalized patients with bacterial nosocomial pneumonia who experience 30-day readmission in the US, 2014-2019

INTRODUCTION

Nosocomial pneumonia (NP) remains associated with excess morbidity and mortality. The effect of NP on measures such as re-admission at 30 days remains unclear. Moreover, differing types of NP may have varying impacts on re-admissions.

METHODS

We conducted a multicenter retrospective cohort study within the Premier Research database, a source containing administrative, pharmacy, and microbiology data. We compared NP patients readmitted with pneumonia (RaP) as the principal diagnosis to those readmitted for other reasons (RaO) with respect to the type of NP (ventilator-associated bacterial pneumonia [VABP], ventilated hospital-acquired bacterial pneumonia [vHABP], and non-ventilated HABP [nvHABP]), and characteristics and outcomes of the index hospitalization.

RESULTS

Among 17,819 patients with NP, 14,123 (79.3%) survived to discharge, of whom 2,151 (15.2%) required an acute readmission within 30 days of index discharge. Of these, 106 (4.9%) were RaP, and the remainder were RaO. At index hospitalization, RaP patients were older (mean age [SD] 67.4 (13.9] vs. 63.0 [15.2] years), more likely medical (44.3% vs. 36.7%), and less chronically ill (median [IQR] Charlson scores (3 [2-5] vs. 4 [2-5]) than persons with RaO. Bacteremia (10.4% vs. 17.5%), need for vasopressors (15.1% vs. 20.0%), dialysis (9.4% vs. 16.5%), and/or sepsis (9.4% vs. 16.5%) or septic shock 14.2% vs. 17.1%) occurred less frequently in the RaP group. With respect to NP type, nvHABP was most common in RaP (47.2%) and VABP in RaO (38.1%).

CONCLUSIONS

One in seven survivors of a hospitalization complicated by NP requires an acute rehospitalization within 30 days. However, few of these readmissions had a principal diagnosis of pneumonia, irrespective of NP type. Of the 5% of NP subjects with RaP, the plurality initially suffered from nvHABP.

Acquisition of extended-spectrum cephalosporin-resistant Gram-negative bacteria: epidemiology and risk factors in a 6-year cohort of 507 severe trauma patients

OBJECTIVES

Severe trauma patients are at higher risk of infection and often exposed to antibiotics, which could favor acquisition of antimicrobial resistance. In this study, we aimed to assess prevalence, acquisition, and factors associated with acquisition of extended-spectrum cephalosporin-resistant Gram-negative bacteria (ESCR-GNB) in severe trauma patients.

METHODS

We conducted a retrospective monocentric cohort study in a French level one Regional Trauma Centre between 01 January 2010and 31 December 2015. Patients admitted for ≥ 7 days, with an Injury Severity Score ≥ 15, and ≥ 1 microbiological sample were included in the analysis. Prevalence and acquisition rate of ESCR-GNB were determined then, factors associated with ESCR-GNB acquisition were assessed using a Cox model.

RESULTS

Of 1873 patients admitted during the study period, 507 were included (median Injury Severity Score = 29 [22-34] and median intensive care unit length of stay = 16 days [10-28]). Most of them (450; 89%) had an antimicrobial therapy. Prevalence of ESCR-GNB increased from 13% to 33% during intensive care unit stay, bringing the ESCR-GNB acquisition rate to 29%. Acquisition of ESCR-GNB was mainly related to AmpC beta-lactamase Enterobacterales and was independently associated with mechanical ventilation needs (hazard ratio [HR] = 6.39; 95% confidence interval [CI] [1.51-27.17]; P = 0.01), renal replacement therapy needs (HR = 2.44; 95% CI [1.24-4.79]; P = 0.01), exposure to cephalosporins (HR = 1.06; 95% CI [1.01-1.12]; P = 0.02), and/or combination therapy with non-beta-lactam antibiotics such as vancomycin, linezolid, clindamycin, or metronidazole (HR = 1.03; 95% CI [1.01-1.06]; P = 0.02).

CONCLUSIONS

Acquisition of ESCR-GNB was prevalent in severe trauma patients. Our results suggest selecting antibiotics with caution, particularly in the most severely ill.

Empirical antibiotic therapy for difficult-to-treat Gram-negative infections: when, how, and how long?

PURPOSE OF REVIEW

To discuss empirical therapy for severe infections due to Gram-negative bacteria with difficult-to-treat resistance (GNB-DTR) in current clinical practice, focusing in particular on the positioning of novel therapeutic agents and rapid diagnostic tests.

RECENT FINDINGS

The current era of novel agents active against GNB-DTR and showing differential activity against specific determinants of resistance is an unprecedented scenario, in which the clinical reasoning leading to the choice of the empirical therapy for treating severe GNB-DTR infections is becoming more complex, but it also allows for enhanced treatment precision.

SUMMARY

Novel agents should be used in line with antimicrobial stewardship principles, aimed at reducing selective pressure for antimicrobial resistance. However, this does not mean that they should not be used. Indeed, excesses in restrictive uses may be unethical by precluding access to the most effective and less toxic treatments for patients with severe GNB-DTR infections. Given these premises (the 'how'), empirical treatment with novel agents should be considered in all patients with risk factors for GNB-DTR and severe clinical presentation of acute infection (the 'when'). Furthermore, empirical novel agents should preferably be continued only for a few hours, until de-escalation, modification, or confirmation (as targeted therapy) is made possible by the results of rapid diagnostic tests (the 'how long').