A randomized trial of 7-day doripenem versus 10-day imipenem-cilastatin for ventilator-associated pneumonia

Individualised, short-course antibiotic treatment versus usual long-course treatment for ventilator-associated pneumonia (REGARD-VAP): a multicentre, individually randomised, open-label, non-inferiority trial

BACKGROUND

Ventilator-associated pneumonia (VAP) is associated with increased mortality, prolonged hospitalisation, excessive antibiotic use and, consequently, increased antimicrobial resistance. In this phase 4, randomised trial, we aimed to establish whether a pragmatic, individualised, short-course antibiotic treatment strategy for VAP was non-inferior to usual care.

METHODS

We did an individually randomised, open-label, hierarchical non-inferiority-superiority trial in 39 intensive care units in six hospitals in Nepal, Singapore, and Thailand. We enrolled adults (age ≥18 years) who met the US Centers for Disease Control and Prevention National Healthcare Safety Network criteria for VAP, had been mechanically ventilated for 48 h or longer, and were administered culture-directed antibiotics. In culture-negative cases, empirical antibiotic choices were made depending on local hospital antibiograms reported by the respective microbiology laboratories or prevailing local guidelines. Participants were assessed until fever resolution for 48 h and haemodynamic stability, then randomly assigned (1:1) to individualised short-course treatment (≤7 days and as short as 3-5 days) or usual care (≥8 days, with precise durations determined by the primary clinicians) via permuted blocks of variable sizes (8, 10, and 12), stratified by study site. Independent assessors for recurrent pneumonia and participants were masked to treatment allocation, but clinicians were not. The primary outcome was a 60-day composite endpoint of death or pneumonia recurrence. The non-inferiority margin was prespecified at 12% and had to be met by analyses based on both intention-to-treat (all study participants who were randomised) and per-protocol populations (all randomised study participants who fulfilled the eligibility criteria, met fitness criteria for antibiotic discontinuation, and who received antibiotics for the duration specified by their allocation group). This study is registered with ClinicalTrials.gov, number NCT03382548.

FINDINGS

Between May 25, 2018, and Dec 16, 2022, 461 patients were enrolled and randomly assigned to the short-course treatment group (n=232) or the usual care group (n=229). Median age was 64 years (IQR 51-74) and 181 (39%) participants were female. 460 were included in the intention-to-treat analysis after excluding one withdrawal (231 in the short-course group and 229 in the usual care group); 435 participants received the allocated treatment and fulfilled eligibility criteria, and were included in the per-protocol population. Median antibiotic treatment duration for the index episodes of VAP was 6 days (IQR 5-7) in the short-course group and 14 days (10-21) in the usual care group. 95 (41%) of 231 participants in the short-course group met the primary outcome, compared with 100 (44%) of 229 in the usual care group (risk difference -3% [one-sided 95% CI -∞ to 5%]). Results were similar in the per-protocol population. Non-inferiority of short-course antibiotic treatment was met in the analyses, although superiority compared with usual care was not established. In the per-protocol population, antibiotic side-effects occurred in 86 (38%) of 224 in the usual care group and 17 (8%) of 211 in the short-course group (risk difference -31% [95% CI -37 to -25%; p<0·0001]).

INTERPRETATION

In this study of adults with VAP, individualised shortened antibiotic duration guided by clinical response was non-inferior to longer treatment durations in terms of 60-day mortality and pneumonia recurrence, and associated with substantially reduced antibiotic use and side-effects. Individualised, short-course antibiotic treatment for VAP could help to reduce the burden of side-effects and the risk of antibiotic resistance in high-resource and resource-limited settings.

FUNDING

UK Medical Research Council; Singapore National Medical Research Council.

TRANSLATIONS

For the Thai and Nepali translations of the abstract see Supplementary Materials section.

Efficacy and safety of antibiotics targeting Gram-negative bacteria in nosocomial pneumonia: a systematic review and Bayesian network meta-analysis

BACKGROUND

Multiple randomized controlled studies have compared numerous antibiotic regimens, including new, recently commercialized antibiotics in the treatment of nosocomial pneumonia (NP). The objective of this Bayesian network meta-analysis (NMA) was to compare the efficacy and the safety of different antibiotic treatments for NP.

METHODS

We conducted a systematic search of PubMed, Medline, Web of Science, EMBASE and the Cochrane Library databases from 2000 through 2021. The study selection included studies comparing antibiotics targeting Gram-negative bacilli in the setting of NP. The primary endpoint was 28 day mortality. Secondary outcomes were clinical cure, microbiological cure and adverse events.

RESULTS

Sixteen studies encompassing 4993 patients were included in this analysis comparing 13 antibiotic regimens. The level of evidence for mortality comparisons ranged from very low to moderate. No significant difference in 28 day mortality was found among all beta-lactam regimens. Only the combination of meropenem plus aerosolized colistin was associated with a significant decrease of mortality compared to using intravenous colistin alone (OR = 0.43; 95% credible interval [0.17-0.94]), based on the results of the smallest trial included. The clinical failure rate of ceftazidime was higher than meropenem with (OR = 1.97; 95% CrI [1.19-3.45]) or without aerosolized colistin (OR = 1.40; 95% CrI [1.00-2.01]), imipemen/cilastatin/relebactam (OR = 1.74; 95% CrI [1.03-2.90]) and ceftazidime/avibactam (OR = 1.48; 95% CrI [1.02-2.20]). For microbiological cure, no substantial difference between regimens was found, but ceftolozane/tazobactam had the highest probability of being superior to comparators. In safety analyses, there was no significant difference between treatments for the occurrence of adverse events, but acute kidney failure was more common in patients receiving intravenous colistin.

CONCLUSIONS

This network meta-analysis suggests that most antibiotic regimens, including new combinations and cefiderocol, have similar efficacy and safety in treating susceptible Gram-negative bacilli in NP. Further studies are necessary for NP caused by multidrug-resistant bacteria. Registration PROSPERO CRD42021226603.

When to Stop Antibiotics in the Critically Ill?

Over the past century, antibiotic usage has skyrocketed in the treatment of critically ill patients. There have been increasing calls to establish guidelines for appropriate treatment and durations of antibiosis. Antibiotic treatment, even when appropriately tailored to the patient and infection, is not without cost. Short term risks-hepatic/renal dysfunction, intermediate effects-concomitant superinfections, and long-term risks-potentiating antimicrobial resistance (AMR), are all possible consequences of antimicrobial administration. These risks are increased by longer periods of treatment and unnecessarily broad treatment courses. Recently, the literature has focused on multiple strategies to determine the appropriate duration of antimicrobial therapy. Further, there is a clinical shift to multi-modal approaches to determine the most suitable timepoint at which to end an antibiotic course. An approach utilising biomarker assays and an inter-disciplinary team of pharmacists, nurses, physicians, and microbiologists appears to be the way forward to develop sound clinical decision-making surrounding antibiotic treatment.

Molecular pharmacodynamics of meropenem for nosocomial pneumonia caused by Pseudomonas aeruginosa

Hospital-acquired pneumonia (HAP) is a leading cause of morbidity and mortality, commonly caused by Pseudomonas aeruginosa. Meropenem is a commonly used therapeutic agent, although emergent resistance occurs during treatment. We used a rabbit HAP infection model to assess the bacterial kill and resistance pharmacodynamics of meropenem. Meropenem 5 mg/kg administered subcutaneously (s.c.) q8h (±amikacin 3.33-5 mg/kg q8h administered intravenously[i.v.]) or meropenem 30 mg/kg s.c. q8h regimens were assessed in a rabbit lung infection model infected with P. aeruginosa, with bacterial quantification and phenotypic/genotypic characterization of emergent resistant isolates. The pharmacokinetic/pharmacodynamic output was fitted to a mathematical model, and human-like regimens were simulated to predict outcomes in a clinical context. Increasing meropenem monotherapy demonstrated a dose-response effect to bacterial kill and an inverted U relationship with emergent resistance. The addition of amikacin to meropenem suppressed the emergence of resistance. A network of porin loss, efflux upregulation, and increased expression of AmpC was identified as the mechanism of this emergent resistance. A bridging simulation using human pharmacokinetics identified meropenem 2 g i.v. q8h as the licensed clinical regimen most likely to suppress resistance. We demonstrate an innovative experimental platform to phenotypically and genotypically characterize bacterial emergent resistance pharmacodynamics in HAP. For meropenem, we have demonstrated the risk of resistance emergence during therapy and identified two mitigating strategies: (i) regimen intensification and (ii) use of combination therapy. This platform will allow pre-clinical assessment of emergent resistance risk during treatment of HAP for other antimicrobials, to allow construction of clinical regimens that mitigate this risk.IMPORTANCEThe emergence of antimicrobial resistance (AMR) during antimicrobial treatment for hospital-acquired pneumonia (HAP) is a well-documented problem (particularly in pneumonia caused by Pseudomonas aeruginosa) that contributes to the wider global antimicrobial resistance crisis. During drug development, regimens are typically determined by their sufficiency to achieve bactericidal effect. Prevention of the emergence of resistance pharmacodynamics is usually not characterized or used to determine the regimen. The innovative experimental platform described here allows characterization of the emergence of AMR during the treatment of HAP and the development of strategies to mitigate this. We have demonstrated this specifically for meropenem-a broad-spectrum antibiotic commonly used to treat HAP. We have characterized the antimicrobial resistance pharmacodynamics of meropenem when used to treat HAP, caused by initially meropenem-susceptible P. aeruginosa, phenotypically and genotypically. We have also shown that intensifying the regimen and using combination therapy are both strategies that can both treat HAP and suppress the emergence of resistance.

Individual meropenem epithelial lining fluid and plasma PK/PD target attainment

It is unclear whether plasma is a reliable surrogate for target attainment in the epithelial lining fluid (ELF). The objective of this study was to characterize meropenem target attainment in plasma and ELF using prospective samples. The first 24-hour T>MIC was evaluated vs 1xMIC and 4xMIC targets at the patient (i.e., fixed MIC of 2 mg/L) and population [i.e., cumulative fraction of response (CFR) according to EUCAST MIC distributions] levels for both plasma and ELF. Among 65 patients receiving ≥24 hours of treatment, 40% of patients failed to achieve >50% T>4xMIC in plasma and ELF, and 30% of patients who achieved >50% T>4xMIC in plasma had <50% T>4xMIC in ELF. At 1xMIC and 4xMIC targets, 3% and 25% of patients with >95% T>MIC in plasma had <50% T>MIC in ELF, respectively. Those with a CRCL >115 mL/min were less likely to achieve >50%T>4xMIC in ELF (P < 0.025). In the population, CFR for Escherichia coli at 1xMIC and 4xMIC was >97%. For Pseudomonas aeruginosa, CFR was ≥90% in plasma and ranged 80%-85% in ELF at 1xMIC when a loading dose was applied. CFR was reduced in plasma (range: 75%-81%) and ELF (range: 44%-60%) in the absence of a loading dose at 1xMIC. At 4xMIC, CFR for P. aeruginosa was 60%-86% with a loading dose and 18%-62% without a loading dose. We found that plasma overestimated ELF target attainment inup to 30% of meropenem-treated patients, CRCL >115 mL/min decreased target attainment in ELF, and loading doses increased CFR in the population.

Evaluating antibiotic therapy for ventilator-associated pneumonia caused by gram-negative bacilli

Introduction

Ventilator-associated pneumonias (VAPs) are a complication of mechanical ventilation in the intensive care unit (ICU) that increase length of stay, morbidity, and mortality. While identifying and treating infections early is paramount to improving patient outcomes, more and more data demonstrate limited courses of antibiotics improve outcomes. Prolonged (10-14 day) courses of antibiotics have remained the standard of care for pneumonia due to gram-negative bacilli (GNR). We aimed to review our GNR VAPs to assess risk factors for recurrent GNR infections.

Methods

We reviewed trauma patients who developed VAP from 02/2019 through 05/2022. Demographics, injury characteristics, and outcomes were reviewed with a focus on pneumonia details including the cultured pathogen(s), antibiotic(s) used, treatment duration, and presence of recurrent infections. We then compared single episode VAPs to multiple episode VAPs among patients infected by GNRs.

Results

Eleven of the fifty trauma patients admitted to the ICU suffered a VAP caused by a GNR. Of these eleven patients, six experienced a recurrent infection, four of which were caused by Pseudomonas aeruginosa and two of which were caused by Enterobacter aerogenes. Among the patients who received ten days of antibiotic treatment, half suffered a recurrence. Although, there was no difference in the microbiology or antibiotic duration between the recurrences and single episodes.

Conclusion

Despite prolonged use of antibiotics, we found that the risk of recurrent or persistent infections was high among patients with VAP due to GNB. Further study is needed to determine optimal treatment to minimize the risk of these recurrences.

Key message

Ventilator-associated pneumonia due to gram-negative bacilli is a rare but high morbidity complication in intensive care units. Despite prolonged duration of therapy, these infections still appear to account for many recurrent infections and further study into optimal therapy is warranted.

Short-course versus prolonged-course antibiotic regimens for ventilator-associated pneumonia: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Current guidelines recommend short-duration antibiotic therapy for non-fermenting gram-negative bacilli (NF-GNB) ventilator-associated pneumonia (VAP) which may be associated with a higher recurrence of pneumonia. In this meta-analysis, we aimed to compare short- versus prolonged-course antibiotic regimens for VAP.

METHODS

We searched several databases for randomized controlled trials (RCTs) that compared the effectiveness of a short- versus long-course of antibiotic treatment in patients with VAP. Data analysis was performed using RevMan 5.4.

RESULTS

Our pooled analysis consisted of six RCTs. For 28-day mortality, no significant difference was found between the prolonged course and the short course. Administration of a short course of antibiotics increased the risk of recurrence of pneumonia in patients with VAP due to NF-GNB (RR 1.73; 95% CI: 1.17-2.54). Secondary outcomes, such as clinical resolution, duration of ICU stay, and duration of mechanical ventilation, revealed no significant difference between the two regimens. The quality of evidence was low for most outcomes.

CONCLUSIONS

Low-quality evidence suggests that a short course of antibiotics is associated with a higher recurrence of pneumonia in NF-GNB VAP with no difference in mortality as compared to a prolonged course. For definitive conclusions, large-scale and blinded RCTs are required.

Management of pneumonia in the critically ill

Pneumonias continue to be major public health issues and are commonly encountered in the intensive care setting. The most common types of pneumonia leading to critical illness include severe community acquired pneumonia, hospital acquired pneumonia, and ventilator associated pneumonia. Early evaluation, diagnosis, and escalation to appropriate levels of care are imperative to improving survival. Treatment remains challenging with the need to balance antibiotic stewardship and minimizing patient harm. As evidenced in the most recent society guidelines, the identification of risk factors for severe disease and the causative pathogens are crucial in guiding the most appropriate therapy.

International consensus recommendations for the use of prolonged-infusion beta-lactam antibiotics: Endorsed by the American College of Clinical Pharmacy, British Society for Antimicrobial Chemotherapy, Cystic Fibrosis Foundation, European Society of Clinical Microbiology and Infectious Diseases, Infectious Diseases Society of America, Society of Critical Care Medicine, and Society of Infectious Diseases Pharmacists

Intravenous β-lactam antibiotics remain a cornerstone in the management of bacterial infections due to their broad spectrum of activity and excellent tolerability. β-lactams are well established to display time-dependent bactericidal activity, where reductions in bacterial burden are directly associated with the time that free drug concentrations remain above the minimum inhibitory concentration (MIC) of the pathogen during the dosing interval. In an effort to take advantage of these bactericidal characteristics, prolonged (extended and continuous) infusions (PIs) can be applied during the administration of intravenous β-lactams to increase time above the MIC. PI dosing regimens have been implemented worldwide, but implementation is inconsistent. We report consensus therapeutic recommendations for the use of PI β-lactams developed by an expert international panel with representation from clinical pharmacy and medicine. This consensus guideline provides recommendations regarding pharmacokinetic and pharmacodynamic targets, therapeutic drug-monitoring considerations, and the use of PI β-lactam therapy in the following patient populations: severely ill and nonseverely ill adult patients, pediatric patients, and obese patients. These recommendations provide the first consensus guidance for the use of β-lactam therapy administered as PIs and have been reviewed and endorsed by the American College of Clinical Pharmacy (ACCP), the British Society for Antimicrobial Chemotherapy (BSAC), the Cystic Fibrosis Foundation (CFF), the European Society of Clinical Microbiology and Infectious Diseases (ESCMID), the Infectious Diseases Society of America (IDSA), the Society of Critical Care Medicine (SCCM), and the Society of Infectious Diseases Pharmacists (SIDP).

Comparison of a short versus long-course antibiotic therapy for ventilator-associated pneumonia: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

For ventilator-associated pneumonia (VAP), the safety of short-course versus long-course antibiotic therapy is still debated, especially regarding documented VAP due to non-fermenting Gram-negative bacilli (NF-GNB). The aim of this meta-analysis was to assess the rates of recurrence and relapse of VAP in patients receiving short-course (≤8 days) and long-course (≥10-15 days) of antibiotic therapy.

METHODS

The protocol for this study was registered in the PROSPERO database (ID: CRD42022365138). We performed an electronic search of the relevant literature and limited our search to data published from 2000 until September 1, 2022. We searched for randomized controlled trials (RCTs) in the United States National Library of Medicine, Cochrane Database of Systematic Reviews (CDSR) and the Cochrane Central Register of Controlled Trials (CENTRAL), Embase, National Institutes of Health PubMed/MEDLINE, web of science and Google Scholar databases. The primary endpoint was the recurrence and relapses of VAP, secondary endpoints were 28-day mortality, mechanical ventilation duration, number of extra-pulmonary infections and length of ICU stay.

FINDINGS

We identified five relevant studies involving 1069 patients (530 patients in the short-course group and 539 patients in the long-course group). The meta-analysis did not reveal any significant difference between short and long-course antibiotic therapy for recurrence and relapses of VAP (odd ratio "OR" = 1.48, 95% confidence intervals (CI) [0.96, 2.28], p = 0.08 and OR = 1.45, 95% CI [0.94, 2.22], p = 0.09, respectively), including those due to NF-GNB (OR = 1.90, 95% CI [0.93, 3.33], p = 0.05 and OR = 1.76, 95% CI [0.93, 3.33], p = 0.08, respectively). No difference was found for 28 days-mortality (OR = 1.24, 95% CI [0.92, 1.67], p = 0.16), mechanical ventilation duration, number of extra-pulmonary infections and length of ICU stay. However, short-course therapy significantly increased the number of antibiotic-free days.

INTERPRETATION

Our meta-analysis showed that short-course antibiotic therapy did not result in increased number of recurence and relapses of VAP, suggesting that short-course should be preferred to reduce the exposure to antibiotics.

FUNDING

None.

Imipenem/cilastatin/relebactam efficacy, safety and probability of target attainment in adults with hospital-acquired or ventilator-associated bacterial pneumonia among patients with baseline renal impairment, normal renal function, and augmented renal clearance

Objectives

To assess the relationship between renal function and efficacy/safety of imipenem/cilastatin/relebactam for the treatment of hospital-acquired/ventilator-associated pneumonia (HABP/VABP) from RESTORE-IMI 2 and determine the PTA.

Methods

Adults with HABP/VABP were randomized 1:1 to IV imipenem/cilastatin/relebactam 1.25 g or piperacillin/tazobactam 4.5 g every 6 h for 7-14 days. Initial doses were selected by CL_CR and adjusted thereafter, as appropriate. Outcomes included Day 28 all-cause mortality (ACM), clinical response, microbiological response and adverse events. Population pharmacokinetic modelling and Monte Carlo simulations assessed PTA.

Results

The modified ITT population comprised those with normal renal function (n = 188), augmented renal clearance (ARC; n = 88), mild renal impairment (RI; n = 124), moderate RI (n = 109) and severe RI (n = 22). ACM rates were comparable between treatment arms among all baseline renal function categories. Clinical response rates were comparable between treatment arms for participants with RI and normal renal function but were higher (91.7% versus 44.4%) for imipenem/cilastatin/relebactam-treated versus piperacillin/tazobactam-treated participants with CL_CR ≥250 mL/min (n = 21). Microbiologic response rates were comparable between treatment arms for participants with RI but higher among those treated with imipenem/cilastatin/relebactam in participants with CL_CR ≥90 mL/min (86.6% versus 67.2%). Adverse events were comparable between treatment arms across renal function categories. Joint PTA was >98% for key pathogen MICs for susceptible pathogens (MIC ≤2 mg/L).

Conclusions

Prescribing information-defined dose adjustments in participants with baseline RI and full dosing of imipenem/cilastatin/relebactam 1.25 g every 6 h for participants with normal renal function or augmented renal clearance achieved sufficiently high drug exposures and favourable safety and efficacy profiles.

Methods to appraise available evidence and adequacy of data from a systematic literature review to conduct a robust network meta-analysis of treatment options for patients with hospital-acquired or ventilator-associated bacterial pneumonia

We aimed to determine if available evidence from a previously conducted systematic literature review was sufficient to conduct a robust network meta-analysis (NMA) using the International Society for Pharmacoeconomics and Outcomes Research Good Practice Task Force NMA study questionnaire to evaluate suitability, relevance, and credibility of available randomized-controlled trials (RCT) of antibacterial therapies for treatment of patients with hospital-acquired or ventilator-associated bacterial pneumonia (HABP/VABP). We assessed feasibility and reliability of an NMA for a connected network of RCTs, and then relevance and credibility of the connected network for informing decision-making. This previously conducted systematic literature review using Cochrane dual-reviewer methodology, Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, and PICOTS (population, interventions, comparators, outcomes, timing, and setting) criteria identified 25 citations between 2001 and 2018; 18 were unique RCTs. Trial design characteristics, outcome definitions, assessment time points, and analyses populations varied across studies. Using "clinical response," an efficacy end point to health technology assessment agencies, we assessed potential network credibility, which collapsed from the overall data set to four studies and five interventions. This did not include closed loop(s) needed to assess consistency. Of the studies reporting clinical response, >70% of patients were ventilated at baseline with mean Acute Physiologic Assessment and Chronic Health Evaluation II scores from 14.7 to 17.5. Pseudomonas aeruginosa (range, 18.4-64.1%) and Klebsiella spp. (range, 1.6-49%) were the most common causative pathogens. We identified relevant RCTs for most standard-of-care agents approved for HABP/VABP, which provided a comprehensive evidence base. In summary, our appraisal of available evidence for the clinical response outcome among adult patients with HABP/VABP does not support the conduct of a scientifically robust and clinically meaningful NMA. Although this data is vital to registration, there are significant limitations in these trials for health technology assessments, payor decisions, guidelines, and protocol decisions.

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.

Duration of antibiotic therapy in Gram-negative infections with a particular focus on multidrug-resistant pathogens

PURPOSE OF REVIEW

Antimicrobial overuse is a major health problem that contributes to antimicrobial resistance (AMR). Infections with Gram-negative bacilli (GNB) and multidrug-resistant organisms (MDRs) are associated with high morbidity and mortality, particularly in patients with underlying medical conditions.

RECENT FINDINGS

Although many recent studies have been published about the novel antibiotics in treating infections including those due to MDR-GNB, the optimal duration of treatment (DOT) remains inconclusive. Recent observation has supported that short antibiotic therapy (SAT) decreases AMR and adverse effects. This narrative review provides an overview of the most recent published studies on the duration of therapy in the treatment of GNB infections, including hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP), intra-abdominal infections (IAIs), bloodstream infections (BSIs) and urinary tract infections (UTIs), with a particular focus on MDR-GNB.

SUMMARY

Studies showed different outcomes when comparing SAT to long antimicrobial therapy (LAT). No generalization can be made on all sites of infections and different GNBs. Further studies are needed to address the optimal DOT in MDR-GNB, as this group is underrepresented in recent studies.

Doripenem in the Treatment of Patients with Nosocomial Pneumonia: A Meta-Analysis

Introduction: Clinically, doripenem therapy for nosocomial pneumonia remains a serious concern. The purpose of this meta-analysis was to explore the efficacy and the safety of doripenem therapy for nosocomial pneumonia in comparison with other antimicrobial agents. Methods: Studies were eligible for inclusion only if they directly compared the clinical effectiveness of doripenem and other antimicrobial agent therapies for nosocomial pneumonia in adult patients between 1 January 2000 and 30 April 2022. All studies were included if they reported one or more of the following outcomes: clinical cure rate, microbiological cure rate, all-cause mortality, and adverse events. Results: Six randomized controlled trials and three retrospective studies were included in the meta-analysis. There were 952 patients in the doripenem group and 1183 patients in the comparator group. The comparator antimicrobial agents included imipenem/cilastatin, meropenem, and piperacillin/tazobactam. Seven studies had a high risk of bias. Doripenem therapy for nosocomial pneumonia had a microbiological cure rate, a clinical cure rate, an all-cause mortality, and adverse events similar to those of comparators. Conclusions: The efficacy and the safety of doripenem therapy for nosocomial pneumonia were comparable with those of comparators. Randomized controlled trials are needed to confirm the role of doripenem in nosocomial pneumonia therapy.

Comparison of 8 versus 15 days of antibiotic therapy for Pseudomonas aeruginosa ventilator-associated pneumonia in adults: a randomized, controlled, open-label trial

PURPOSE

Compared to long duration of antibiotic therapy, a short duration has a comparable clinical efficacy for ventilator-associated pneumonia (VAP), with the exception of documented VAP of non-fermenting Gram-negative bacilli (NF-GNB), including Pseudomonas aeruginosa (PA). We aimed to assess the non-inferiority of a short duration of antibiotics (8 days) vs. prolonged antibiotic therapy (15 days) in VAP due to PA (PA-VAP).

METHODS

We conducted a nationwide, randomized, open-labeled, multicenter, non-inferiority trial to evaluate optimal duration of antibiotic treatment in PA-VAP. Eligible patients were adults with diagnosis of PA-VAP and randomly assigned in 1:1 ratio to receive a short-duration treatment (8 days) or a long-duration treatment (15 days). A pre-specified analysis was used to assess a composite endpoint combining mortality and PA-VAP recurrence rate during hospitalization in the intensive care unit (ICU) within 90 days.

RESULTS

In intention-to-treat population (n = 186), the percentage of patients who reached the composite endpoint was 25.5% (N = 25/98) in the 15-day group versus 35.2% (N = 31/88) in the 8-day group (difference 9.7%, 90% confidence interval (CI) 0.0-21.2%). The percentage of recurrence of PA-VAP during the ICU stay was 9.2% in the 15-day group versus 17% in the 8-day group. The two groups had similar median days of mechanical ventilation, of ICU stay, number of extra pulmonary infections and acquisition of multidrug-resistant (MDR) pathogens during ICU stay.

CONCLUSIONS

Our study showed no differences in the composite or separate outcomes (90-day mortality or VAP recurrence) between short- and long-duration treatments for PA-VAP. However, the lack of power limits the interpretation of this study.

Treatment of ventilator-associated pneumonia due to carbapenem-resistant Gram-negative bacteria with novel agents: a contemporary, multidisciplinary ESGCIP perspective

INTRODUCTION

: In the past 15 years, treatment of VAP caused by carbapenem-resistant Gram-negative bacteria (CR-GNB) has represented an intricate challenge for clinicians.

AREAS COVERED

In this perspective article, we discuss the available clinical data about novel agents for the treatment of CR-GNB VAP, together with general PK/PD principles for the treatment of VAP, in the attempt to provide some suggestions for optimizing antimicrobial therapy of CR-GNB VAP in the daily clinical practice.

EXPERT OPINION

Recently, novel BL and BL/BLI combinations have become available that have shown potent in vitro activity against CR-GNB and have attracted much interest as novel, less toxic, and possibly more efficacious options for the treatment of CR-GNB VAP compared with previous standard of care. Besides randomized controlled trials, a good solution to enrich our knowledge on how to use these novel agents at best in the near future, while at the same time remaining adherent to current evidence-based guidelines, is to improve our collaboration to conduct larger multinational observational studies to collect sufficiently large populations treated in real life with those novel agents for which guidelines currently do not provide a recommendation (in favor or against) for certain causative organisms.

Microbiology, empiric therapy and its impact on the outcomes of nonventilated hospital-acquired, ventilated hospital-acquired, and ventilator-associated bacterial pneumonia in the United States, 2014-2019

OBJECTIVE

To explore whether microbiology profiles and the impact of inappropriate empiric treatment differ in the setting of hospital-acquired bacterial pneumonia that requires subsequent mechanical ventilation (vHABP) versus one that does not (nvHABP) versus ventilator-associated bacterial pneumonia (VABP).

DESIGN

Multicenter retrospective cohort study within Premier Research database, 2014-2019.

METHODS

We identified cases based on a previously published International Classification of Disease, Ninth Revision/Tenth Revision Clinical Modification (ICD-9/ICD-10-CM) algorithm, and we compared the 3 groups with respect to the bacterial pathogens isolated from their blood, sputum, or lower airway samples, and their respective rates of exposure to inappropriate empiric treatment. Using regression modeling we computed the effect of inappropriate empiric treatment on outcomes.

RESULTS

Among 17,819 patients who met enrollment criteria, 26.5% had nvHABP, 25.6% vHAPB, and 47.9% VABP. S. aureus (majority methicillin-susceptible) was the most frequently isolated organism, followed P. aeruginosa, K. pneumoniae, and E. coli with variations across the conditions. Rates of carbapenem resistance were highest in VABP (9.1%) and to third-generation cephalosporins in vHABP (14.9%). Patients with nvHABP were most likely to receive inappropriate empiric treatment (8.5%). Although inappropriate empiric treatment was associated with an increase in adjusted postinfection-onset hospital length of stay (2.3 days) and cost ($12,142), its greatest magnitude was in the nvHABP group (4.9 days, $13,147).

CONCLUSIONS

Substantial microbiologic differences exist among populations who suffer nvHABP, vHABP, and VABP, and inappropriate empiric treatment significantly worsens utilization outcomes. Given the moderate rates of carbapenem resistance and third-generation cephalosporin resistance, all patients require empiric coverage for a range of bacteria, including those targeting extended-spectrum β-lactamase and carbapenem resistance where appropriate.

Different Surgeon, Different Duration: Lack of Consensus on the Appropriate Duration of Antimicrobial Prophylaxis and Therapy in Surgical Practice

Background: The principles of antimicrobial stewardship promote the appropriate prescribing of agents with respect to efficacy, safety, duration, and cost. Antibiotic resistance often results from inappropriate use (e.g., indication, selection, duration). We evaluated practice variability in duration of antimicrobials in surgical infection treatment (Rx) or prophylaxis (Px). Hypothesis: There is lack of consensus regarding the duration of antibiotic Px and Rx for many common indications. Methods: A survey was distributed to the Surgical Infection Society (SIS) regarding the use of antimicrobial agents for a variety of scenarios. Standard descriptive statistics were used to compare survey responses. Heterogeneity among question responses were compared using the Shannon Index, expressed as natural units (nats). Results: Sixty-three SIS members responded, most of whom (67%) have held a leadership position within the SIS or contributed as an annual meeting moderator or discussant; 76% have been in practice for more than five years. Regarding peri-operative Px, more than 80% agreed that a single dose is adequate for most indications, with the exceptions of gangrenous cholecystitis (40% single dose, 38% pre-operative +24 hours) and inguinal hernia repair requiring a bowel resection (70% single dose). There was more variability regarding the use of antibiotic Px for various bedside procedures with respondents split between none needed (range, 27%-66%) versus a single dose (range, 31%-67%). Opinions regarding the duration of antimicrobial Rx for hospitalized patients who have undergone a source control operation or procedure varied widely based on indication. Only two of 20 indications achieved more than 60% consensus despite available class 1 evidence: seven days for ventilator-associated pneumonia (77%), and four plus one days for perforated appendicitis (62%). Conclusions: Except for peri-operative antibiotic Px, there is little consensus regarding antibiotic duration among surgical infection experts, despite class 1 evidence and several available guidelines. This highlights the need for further high-level research and better dissemination of guidelines.

Therapeutic Drug Monitoring of Antibiotics: Defining the Therapeutic Range

PURPOSE

In the present narrative review, the authors aimed to discuss the relationship between the pharmacokinetic/pharmacodynamic (PK/PD) of antibiotics and clinical response (including efficacy and toxicity). In addition, this review describes how this relationship can be applied to define the therapeutic range of a particular antibiotic (or antibiotic class) for therapeutic drug monitoring (TDM).

METHODS

Relevant clinical studies that examined the relationship between PK/PD of antibiotics and clinical response (efficacy and response) were reviewed. The review (performed for studies published in English up to September 2021) assessed only commonly used antibiotics (or antibiotic classes), including aminoglycosides, beta-lactam antibiotics, daptomycin, fluoroquinolones, glycopeptides (teicoplanin and vancomycin), and linezolid. The best currently available evidence was used to define the therapeutic range for these antibiotics.

RESULTS

The therapeutic range associated with maximal clinical efficacy and minimal toxicity is available for commonly used antibiotics, and these values can be implemented when TDM for antibiotics is performed. Additional data are needed to clarify the relationship between PK/PD indices and the development of antibiotic resistance.

CONCLUSIONS

TDM should only be regarded as a means to achieve the main goal of providing safe and effective antibiotic therapy for all patients. The next critical step is to define exposures that can prevent the development of antibiotic resistance and include these exposures as therapeutic drug monitoring targets.

Risk Factors and Algorithms for the Empirical Treatment of Hospital-Acquired Pneumonia and Ventilator-Associated Pneumonia

Hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) continue to be major concerns for morbidity and mortality, especially in patients treated in the intensive care unit. With the rise in multidrug-resistant organisms, HAP and VAP treatment is challenged by the need for early appropriate treatment, with broad-spectrum agents, while still being aware of the principles of antibiotic stewardship. The two major society guidelines proposed a series of risk factors in their most recent guidelines to help identify patients who can most benefit from narrow- or broad-spectrum initial empiric antibiotic therapy. The guidelines reveal differences in the proposed risk factors and treatment approaches, as well as major similarities.

Short- versus prolonged-course antibiotic therapy for sepsis or infectious diseases in critically ill adults: a systematic review and meta-analysis

BACKGROUND

The 2016 International Guidelines for the Management of Sepsis and Septic Shock recommend antibiotic therapy for 7-10 days for most patients with sepsis. However, evidence on critically ill patients is limited. Thus, we conducted the first systematic review and meta-analysis comparing the effectiveness and adverse events of shorter- (≤1 week) with longer-course antibiotics in adults with critical infections including sepsis.

METHODS

We searched the MEDLINE, Cochrane Central Register of Controlled Trials, and Igaku Chuo Zasshi databases for randomised controlled trials (RCTs) and observational studies (OSs) from inception to 31 March 2021.

RESULTS

We included 6 of 3,766 identified articles, incorporating data from 4 RCTs and 2 OSs (1,721 patients) in meta-analyses. Three RCTs and one OS focussed on ventilator-associated pneumonia, and one RCT and one OS investigated intra-abdominal infections. The severity score levels were similar to that of sepsis, but no study comprehensively focussing on sepsis was found. There were no significant differences in mortality at a maximum follow-up of 30 days (RR 1.08, 95%CI 0.80-1.46); 28-day mortality, clinical cure, the occurrence of new events, and the emergence of resistant organisms between the groups in the RCTs. The OSs findings were consistent. The quality of evidence was assessed as very low to moderate using the GRADE approach, with no uniform description of severity scores, sepsis, or adverse events.

CONCLUSIONS

Shorter, fixed-duration antibiotic therapy for clinically heterogeneous sepsis or severe infections was not associated with poorer outcomes, but the overall quality of evidence was poor.

The Epidemiology and Pathogenesis and Treatment of Pseudomonas aeruginosa Infections: An Update

Pseudomonas aeruginosa is a Gram-negative bacterial pathogen that is a common cause of nosocomial infections, particularly pneumonia, infection in immunocompromised hosts, and in those with structural lung disease such as cystic fibrosis. Epidemiological studies have identified increasing trends of antimicrobial resistance, including multi-drug resistant (MDR) isolates in recent years. P. aeruginosa has several virulence mechanisms that increase its ability to cause severe infections, such as secreted toxins, quorum sensing and biofilm formation. Management of P. aeruginosa infections focuses on prevention when possible, obtaining cultures, and prompt initiation of antimicrobial therapy, occasionally with combination therapy depending on the clinical scenario to ensure activity against P. aeruginosa. Newer anti-pseudomonal antibiotics are available and are increasingly being used in the management of MDR P. aeruginosa.

Antibiotics for hospital-acquired pneumonia in neonates and children

BACKGROUND

Hospital-acquired pneumonia is one of the most common hospital-acquired infections in children worldwide. Most of our understanding of hospital-acquired pneumonia in children is derived from adult studies. To our knowledge, no systematic review with meta-analysis has assessed the benefits and harms of different antibiotic regimens in neonates and children with hospital-acquired pneumonia.

OBJECTIVES

To assess the beneficial and harmful effects of different antibiotic regimens for hospital-acquired pneumonia in neonates and children.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, three other databases, and two trial registers to February 2021, together with reference checking, citation searching, and contact with study authors to identify additional studies.

SELECTION CRITERIA

We included randomised clinical trials comparing one antibiotic regimen with any other antibiotic regimen for hospital-acquired pneumonia in neonates and children.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed studies for inclusion, extracted data, and assessed risk of bias. We assessed the certainty of the evidence using the GRADE approach. Our primary outcomes were all-cause mortality and serious adverse events; our secondary outcomes were health-related quality of life, pneumonia-related mortality, non-serious adverse events, and treatment failure. Our primary time point of interest was at maximum follow-up.

MAIN RESULTS

We included four randomised clinical trials (84 participants). We assessed all trials as having high risk of bias. We did not conduct any meta-analyses, as the included trials did not compare similar antibiotic regimens. Each of the four trials assessed a different comparison, as follows: cefepime versus ceftazidime; linezolid versus vancomycin; meropenem versus cefotaxime; and ceftobiprole versus cephalosporin. Only one trial reported our primary outcomes of all-cause mortality and serious adverse events. Three trials reported our secondary outcome of treatment failure. Two trials primarily included community-acquired pneumonia and hospitalised children with bacterial infections, hence the children with hospital-acquired pneumonia constituted subgroups of the total sample sizes. Where outcomes were reported, the certainty of the evidence was very low for each of the comparisons. We are unable to draw meaningful conclusions from the numerical results. None of the included trials assessed health-related quality of life, pneumonia-related mortality, or non-serious adverse events.

AUTHORS' CONCLUSIONS

The relative beneficial and harmful effects of different antibiotic regimens remain unclear due to the very low certainty of the available evidence. The current evidence is insufficient to support any antibiotic regimen being superior to another. Randomised clinical trials assessing different antibiotic regimens for hospital-acquired pneumonia in children and neonates are warranted.

Timing of antibiotic therapy in the ICU

Severe or life threatening infections are common among patients in the intensive care unit (ICU). Most infections in the ICU are bacterial or fungal in origin and require antimicrobial therapy for clinical resolution. Antibiotics are the cornerstone of therapy for infected critically ill patients. However, antibiotics are often not optimally administered resulting in less favorable patient outcomes including greater mortality. The timing of antibiotics in patients with life threatening infections including sepsis and septic shock is now recognized as one of the most important determinants of survival for this population. Individuals who have a delay in the administration of antibiotic therapy for serious infections can have a doubling or more in their mortality. Additionally, the timing of an appropriate antibiotic regimen, one that is active against the offending pathogens based on in vitro susceptibility, also influences survival. Thus not only is early empiric antibiotic administration important but the selection of those agents is crucial as well. The duration of antibiotic infusions, especially for β-lactams, can also influence antibiotic efficacy by increasing antimicrobial drug exposure for the offending pathogen. However, due to mounting antibiotic resistance, aggressive antimicrobial de-escalation based on microbiology results is necessary to counterbalance the pressures of early broad-spectrum antibiotic therapy. In this review, we examine time related variables impacting antibiotic optimization as it relates to the treatment of life threatening infections in the ICU. In addition to highlighting the importance of antibiotic timing in the ICU we hope to provide an approach to antimicrobials that also minimizes the unnecessary use of these agents. Such approaches will increasingly be linked to advances in molecular microbiology testing and artificial intelligence/machine learning. Such advances should help identify patients needing empiric antibiotic therapy at an earlier time point as well as the specific antibiotics required in order to avoid unnecessary administration of broad-spectrum antibiotics.

Penetration of Antibacterial Agents into Pulmonary Epithelial Lining Fluid: An Update

A comprehensive review of drug penetration into pulmonary epithelial lining fluid (ELF) was previously published in 2011. Since then, an extensive number of studies comparing plasma and ELF concentrations of antibacterial agents have been published and are summarized in this review. The majority of the studies included in this review determined ELF concentrations of antibacterial agents using bronchoscopy and bronchoalveolar lavage, and this review focuses on intrapulmonary penetration ratios determined with area under the concentration-time curve from healthy human adult studies or pharmacokinetic modeling of various antibacterial agents. If available, pharmacokinetic/pharmacodynamic parameters determined from preclinical murine infection models that evaluated ELF concentrations are also provided. There are also a limited number of recently published investigations of intrapulmonary penetration in critically ill patients with lower respiratory tract infections, where greater variability in ELF concentrations may exist. The significance of these changes may impact the intrapulmonary penetration in the setting of infection, and further studies relating ELF concentrations to clinical response are needed. Phase I drug development programs now include assessment of initial pharmacodynamic target values for pertinent organisms in animal models, followed by evaluation of antibacterial penetration into the human lung to assist in dosage selection for clinical trials in infected patients. The recent focus has been on β-lactam agents, including those in combination with β-lactamase inhibitors, particularly due to the rise of multidrug-resistant infections. This manifests as a large portion of the review focusing on cephalosporins and carbapenems, with or without β-lactamase inhibitors, in both healthy adult subjects and critically ill patients with lower respiratory tract infections. Further studies are warranted in critically ill patients with lower respiratory tract infections to evaluate the relationship between intrapulmonary penetration and clinical and microbiological outcomes. Our clinical research experience with these studies, along with this literature review, has allowed us to outline key steps in developing and evaluating dosage regimens to treat extracellular bacteria in lower respiratory tract infections.

Ceftolozane/tazobactam probability of target attainment and outcomes in participants with augmented renal clearance from the randomized phase 3 ASPECT-NP trial

Background

The randomized, double-blind, phase 3 ASPECT-NP trial evaluated the efficacy of 3 g of ceftolozane/tazobactam (C/T) versus 1 g of meropenem infused every 8 h for 8 to 14 days for treatment of adults with hospital-acquired bacterial pneumonia (HABP) or ventilator-associated bacterial pneumonia (VABP). We assessed the probability of target attainment and compared efficacy outcomes from ASPECT-NP in participants with augmented renal clearance (ARC) versus those with normal renal function.

Methods

Baseline renal function was categorized as normal renal function (creatinine clearance 80–130 mL/min) or ARC (creatinine clearance > 130 mL/min). Population pharmacokinetic models informed Monte Carlo simulations to assess probability of target attainment in plasma and pulmonary epithelial lining fluid. Outcomes included 28-day all-cause mortality and clinical cure and per-participant microbiologic cure rates at the test-of-cure visit.

Results

A > 99% and > 80% probability of target attainment was demonstrated for ceftolozane and tazobactam, respectively, in simulated plasma and epithelial lining fluid. Within treatment arms, 28-day all-cause mortality rates in participants with normal renal function (C/T, n = 131; meropenem, n = 123) and ARC (C/T, n = 96; meropenem, n = 113) were comparable (data comparisons presented as rate; treatment difference [95% CI]) (C/T: normal renal function, 17.6%; ARC, 17.7%; 0.2 [− 9.6 to 10.6]; meropenem: normal renal function, 20.3%; ARC, 17.7%; − 2.6 [− 12.6 to 7.5]). Clinical cure rates at test-of-cure were also comparable across renal function groups within treatment arms (C/T: normal renal function, 57.3%; ARC, 59.4%; − 2.1 [− 14.8 to 10.8]; meropenem: normal renal function, 59.3%; ARC, 57.5%; 1.8 [− 10.6 to 14.2]). Per-participant microbiologic cure rates at test-of-cure were consistent across renal function groups within treatment arms (C/T: normal renal function, 72.2% [n/N = 70/97]; ARC, 71.4% [n/N = 55/77]; 0.7 [− 12.4 to 14.2]; meropenem: normal renal function, 75.0% [n/N = 66/88]; ARC, 70.0% [n/N = 49/70]; 5.0 [− 8.7 to 19.0]).

Conclusions

C/T and meropenem resulted in 28-day all-cause mortality, clinical cure, and microbiologic cure rates that were comparable between participants with ARC or normal renal function. In conjunction with high probability of target attainment, these results confirm that C/T (3 g) every 8 h is appropriate in patients with HABP/VABP and ARC.

Trial registration ClinicalTrials.gov identifier: NCT02070757, registered February 25, 2014; EudraCT: 2012-002862-11.

A Focus on Evaluating Major Study Limitations in Order to Apply Clinical Trials to Patient Care: Implications for the Healthcare Team

Background: With more than a million new biomedical articles published annually, healthcare providers must stay up to date in order to provide optimal evidence-based patient care. The concise ROOTs (relevance, observe validity, obtain clinically significant results, and translate results to clinical practice) format is a valuable tool to assist with literature evaluation. Purpose: To illustrate how major study limitations found in clinical trials might inhibit the ability to adopt the findings of such studies to patient care. Methods: Examples from published clinical trials that contain major study flaws were used to illustrate, if taken at face value, would lead to erroneous assumptions, and if adopted, could potentiallly harm patients. Conclusion: When evaluating the literature, it is crucial to identify limitations in the published literature that might reduce the internal validity, affect the results, or limit the external validity of clinical trials, hence affecting the usability of literature for patient care. This article provides examples of clinical trials that contain major study limitations with potentially erroneous assumptions. These illustrations are meant to show how important it is to delve deeper into an article before conclusions are drawn.

Understanding the Host in the Management of Pneumonia. An Official American Thoracic Society Workshop Report

Pneumonia causes a significant burden of disease worldwide. Although all populations are at risk of pneumonia, those at extremes of age and those with immunosuppressive disorders, underlying respiratory disease, and critical illness are particularly vulnerable. Although clinical practice guidelines addressing the management and treatment of pneumonia exist, few of the supporting studies focus on the crucial contributions of the host in pneumonia pathogenesis and recovery. Such essential considerations include the host risk factors that lead to susceptibility to lung infections; biomarkers reflecting the host response and the means to pursue host-directed pneumonia therapy; systemic effects of pneumonia on the host; and long-term health outcomes after pneumonia. To address these gaps, the Pneumonia Working Group of the Assembly on Pulmonary Infection and Tuberculosis led a workshop held at the American Thoracic Society meeting in May 2018 with overarching objectives to foster attention, stimulate research, and promote funding for short-term and long-term investigations into the host contributions to pneumonia. The workshop involved participants from various disciplines with expertise in lung infection, pneumonia, sepsis, immunocompromised patients, translational biology, data science, genomics, systems biology, and clinical trials. This workshop report summarizes the presentations and discussions and important recommendations for future clinical pneumonia studies. These recommendations include establishing consensus disease and outcome definitions, improved phenotyping, development of clinical study networks, standardized data and biospecimen collection and protocols, and development of innovative trial designs.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020)

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created as revised from J-SSCG 2016 jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in September 2020 and published in February 2021. An English-language version of these guidelines was created based on the contents of the original Japanese-language version. The purpose of this guideline is to assist medical staff in making appropriate decisions to improve the prognosis of patients undergoing treatment for sepsis and septic shock. We aimed to provide high-quality guidelines that are easy to use and understand for specialists, general clinicians, and multidisciplinary medical professionals. J-SSCG 2016 took up new subjects that were not present in SSCG 2016 (e.g., ICU-acquired weakness [ICU-AW], post-intensive care syndrome [PICS], and body temperature management). The J-SSCG 2020 covered a total of 22 areas with four additional new areas (patient- and family-centered care, sepsis treatment system, neuro-intensive treatment, and stress ulcers). A total of 118 important clinical issues (clinical questions, CQs) were extracted regardless of the presence or absence of evidence. These CQs also include those that have been given particular focus within Japan. This is a large-scale guideline covering multiple fields; thus, in addition to the 25 committee members, we had the participation and support of a total of 226 members who are professionals (physicians, nurses, physiotherapists, clinical engineers, and pharmacists) and medical workers with a history of sepsis or critical illness. The GRADE 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, 79 GRADE-based recommendations, 5 Good Practice Statements (GPS), 18 expert consensuses, 27 answers to background questions (BQs), and summaries of definitions and diagnosis of sepsis were created as responses to 118 CQs. We also incorporated visual information for each CQ according to the time course of treatment, and we will also distribute this as an app. The J-SSCG 2020 is expected to be widely used as a useful bedside guideline in the field of sepsis treatment both in Japan and overseas involving multiple disciplines.

Tigecycline in the Treatment of Ventilator-Associated Pneumonia Due to Stenotrophomonas maltophilia: A Multicenter Retrospective Cohort Study

Introduction

Tigecycline is a potential alternative to trimethoprim–sulfamethoxazole in treating Stenotrophomonas maltophilia infections due to its potent in vitro antimicrobial activity. Clinical evidence regarding the use of tigecycline in the treatment of S. maltophilia infections is scarce. In this study, we assessed the efficacy of tigecycline treating ventilator-associated pneumonia (VAP) due to S. maltophilia in comparison with fluoroquinolones.

Methods

This is a multicenter retrospective cohort study of patients admitted between January 2017 and December 2020 with the diagnosis of VAP caused by S. maltophilia receiving either tigecycline or fluoroquinolones as the definitive therapy ≥ 48 h. Clinical outcomes including 28-day mortality, clinical cure and microbiological cure were analyzed.

Results

Of 82 patients with S. maltophilia VAP included, 46 received tigecycline, and 36 received fluoroquinolones; 70.7% of patients had polymicrobial pneumonia, and the appropriate empiric therapy was applied to only 14.6% of patients. The overall 28-day mortality was 39%. Compared with patients receiving fluoroquinolones, tigecycline therapy resulted in worse clinical cure (32.6% vs. 63.9%, p = 0.009) and microbiological cure (28.6% vs. 59.1%, p = 0.045), while there was no statistical difference between 28-day mortality (47.8% vs. 27.8%, p = 0.105) in the two groups. Similar results were also shown in the inverse probability of treatment weighted univariable regression model and multivariable regression model.

Conclusions

The standard dose of tigecycline therapy was associated with a lower clinical and microbiological cure rate but not associated with an increased 28-day mortality in patients with S. maltophilia VAP compared with fluoroquinolones. Considering the unfavorable clinical outcomes, we therefore recommend against using the standard dose of tigecycline in treating S. maltophilia VAP unless new clinical evidence emerges.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40121-021-00516-5.

Duration of antimicrobial therapy for Gram-negative infections

PURPOSE OF REVIEW

The potential benefits on antimicrobial resistance emergence, incidence of antibiotic-related adverse effects, and health costs have pushed to shorten therapeutic courses for Gram-negative bacilli (GNB) infections. However, the safety of this approach is still under investigation. This review gathers recent contributions to the evaluation of the impact on antimicrobial resistance and clinical outcome of shorter therapeutic courses against GNB infections, and highlights data on the modern approach of adjustable antibiotic duration.

RECENT FINDINGS

Recent advances include data on the safety of 7-day treatment of uncomplicated Enterobacteriaceae bloodstream infections with favorable early 48-h evolution. A promising innovative approach with individualized treatment duration arises, supported by recently published results on GNB bacteremia evaluating fixed antibiotic durations and an adaptive antibiotic duration driven by blood levels of C-reactive protein.

SUMMARY

Recent literature illustrates a strong trend towards shortened antibiotic durations in GNB infections, illustrated by lately published data in GNB bacteremia and ongoing studies in GNB ventilator-associated pneumonia. However, short antibiotic course for specific situations, such as immunodeficiency, drug-resistance, and inadequate source control should be handled with caution because of lack of supportive data.

Superinfection associated with prolonged antibiotic use in non-ventilator associated hospital-acquired pneumonia

Background Non-ventilator associated hospital-acquired pneumonia accounts for significant antibiotic use and is associated with a high rate of resistance emergence. However, the optimal duration of antibiotic treatment is uncertain, especially in cases of non-fermenting gram-negative bacilli. Objective To compare a short course (5-7 days) to a prolonged course (10-14 days) of antibiotics for non-ventilator associated hospital-acquired pneumonia. Methods Data collected retrospectively on patients completed treatment in a Malaysian tertiary hospital from January 2017 till December 2018. Regression analysis determined variables independently associated with clinical outcome. Main outcome measures Clinical resolution, superinfection, 30-day and 90-day all-cause mortality between short and prolonged courses. Results Of the 167 patients included, 112 patients were treated with a short course antibiotic, whereas 55 patients received a prolonged course of therapy. Neither short nor prolonged course group has a significantly higher rate of clinical resolution. Short course group had significantly higher mean ± SD antibiotic-free days (21.9 ± 3.5 versus 15.1 ± 6.2 days, p < 0.001). Higher rate of superinfection was observed in prolonged course group compared to short course group (6.3% versus 18.2%, p = 0.027). For non-ventilator associated hospital-acquired pneumonia caused by non-fermenting gram-negative bacilli, the superinfection rate was higher in prolonged course group (35.7% versus 15.4%, p = 0.385) while 30-day mortality rate was higher in the short course group (38.5% versus 14.3%, p = 0.209). Non-fermenting gram-negative bacilli cause higher rate of superinfection (p = 0.010). Conclusion We found no clinical benefit as defined by clinical resolution and reduction in all-cause mortality in prolonging antimicrobial therapy. Superinfections emerge more frequently in prolonged course of antibiotic therapy and more likely to develop in non-fermenting gram-negative bacilli.

Effect of Antibiotic Discontinuation Strategies on Mortality and Infectious Complications in Critically Ill Septic Patients: A Meta-Analysis and Trial Sequential Analysis

OBJECTIVE

To investigate methods of antibiotic duration minimization and their effect on mortality and infectious complications in critically ill patients.

DATA SOURCES

A systematic search of PubMed, Embase (via Ovid), clinicaltrials.gov, and the Cochrane Central Register of Controlled Trials (via Wiley) (CENTRAL, Issue 2, 2015).

STUDY SELECTION

Randomized clinical trials comparing strategies to minimize antibiotic duration (days) for patients with infections or sepsis in intensive care.

DATA EXTRACTION

A systematic review with meta-analyses and trial sequential analyses of randomized clinical trials. Dichotomous data are presented as relative risk (95% CIs) and p value, and continuous data are presented as mean difference (CI) and p value.

DATA SYNTHESIS

We included 22 randomized clinical trials (6,046 patients). Strategies to minimize antibiotic use included procalcitonin (14 randomized clinical trials), clinical algorithms (two randomized clinical trials), and fixed-antibiotic duration (six randomized clinical trials). Procalcitonin (-1.23 [-1.61 to -0.85]; p < 0.001), but not clinical algorithm-guided antibiotic therapy (-7.41 [-18.18 to 3.37]; p = 0.18), was associated with shorter duration of antibiotic therapy. The intended reduction in antibiotic duration ranged from 3 to 7 days in fixed-duration antibiotic therapy randomized clinical trials. Neither procalcitonin-guided antibiotic treatment (0.91 [0.82-1.01]; p = 0.09), clinical algorithm-guided antibiotic treatment (0.67 [0.30-1.54]; p = 0.35), nor fixed-duration antibiotics (1.21 [0.90-1.63]; p = 0.20) were associated with reduction in mortality. Z-curve for trial sequential analyses of mortality associated with procalcitonin-guided therapy did not reach the trial sequential monitoring boundaries for benefit, harm, or futility (adjusted CI, 0.72-1.10). Trial sequential analyses for mortality associated with clinical algorithm and fixed-duration treatment accumulated less than 5% of the required information size. Despite shorter antibiotic duration, neither procalcitonin-guided therapy (0.93 [0.84-1.03]; p = 0.15) nor fixed-duration antibiotic therapy (1.06 [0.74-1.53]; p = 0.75) was associated with treatment failure.

CONCLUSIONS

Although the duration of antibiotic therapy is reduced with procalcitonin-guided therapy or prespecified limited duration, meta-analysis and trial sequential analyses are inconclusive for mortality benefit. Data on clinical algorithms to guide antibiotic cessation are limited.

Pneumonia

Pneumonia is a common acute respiratory infection that affects the alveoli and distal airways; it is a major health problem and associated with high morbidity and short-term and long-term mortality in all age groups worldwide. Pneumonia is broadly divided into community-acquired pneumonia or hospital-acquired pneumonia. A large variety of microorganisms can cause pneumonia, including bacteria, respiratory viruses and fungi, and there are great geographical variations in their prevalence. Pneumonia occurs more commonly in susceptible individuals, including children of <5 years of age and older adults with prior chronic conditions. Development of the disease largely depends on the host immune response, with pathogen characteristics having a less prominent role. Individuals with pneumonia often present with respiratory and systemic symptoms, and diagnosis is based on both clinical presentation and radiological findings. It is crucial to identify the causative pathogens, as delayed and inadequate antimicrobial therapy can lead to poor outcomes. New antibiotic and non-antibiotic therapies, in addition to rapid and accurate diagnostic tests that can detect pathogens and antibiotic resistance will improve the management of pneumonia.

Antibiotic Stewardship in the Intensive Care Unit. An Official American Thoracic Society Workshop Report in Collaboration with the AACN, CHEST, CDC, and SCCM

Intensive care units (ICUs) are an appropriate focus of antibiotic stewardship program efforts because a large proportion of any hospital’s use of parenteral antibiotics, especially broad-spectrum, occurs in the ICU. Given the importance of antibiotic stewardship for critically ill patients and the importance of critical care practitioners as the front line for antibiotic stewardship, a workshop was convened to specifically address barriers to antibiotic stewardship in the ICU and discuss tactics to overcome these. The working definition of antibiotic stewardship is “the right drug at the right time and the right dose for the right bug for the right duration.” A major emphasis was that antibiotic stewardship should be a core competency of critical care clinicians. Fear of pathogens that are not covered by empirical antibiotics is a major driver of excessively broad-spectrum therapy in critically ill patients. Better diagnostics and outcome data can address this fear and expand efforts to narrow or shorten therapy. Greater awareness of the substantial adverse effects of antibiotics should be emphasized and is an important counterargument to broad-spectrum therapy in individual low-risk patients. Optimal antibiotic stewardship should not focus solely on reducing antibiotic use or ensuring compliance with guidelines. Instead, it should enhance care both for individual patients (by improving and individualizing their choice of antibiotic) and for the ICU population as a whole. Opportunities for antibiotic stewardship in common ICU infections, including community- and hospital-acquired pneumonia and sepsis, are discussed. Intensivists can partner with antibiotic stewardship programs to address barriers and improve patient care.

Pharmacokinetics and Pharmacodynamics of Ceftolozane/Tazobactam in Critically Ill Patients With Augmented Renal Clearance

OBJECTIVE

To determine whether established ceftolozane/tazobactam (C/T) dosing is adequate for patients with augmented renal clearance (ARC) and bacterial infection.

METHODS

ARC (creatinine clearance [CrCl] ≥ 130 mL/min) was confirmed by directly measured CrCl in 11 critically ill patients in a phase 1 pharmacokinetics study. Patients received 3 g C/T (ceftolozane 2 g/tazobactam 1 g) as a 60-minute intravenous infusion. Pharmacokinetic sampling occurred at 0 (predose), 1, 2, 4, 6, and 8 hours after the start of the infusion. Noncompartmental analyses were conducted on concentration data. The following pharmacodynamic targets were evaluated: time that free (unbound) drug concentrations exceeded the minimum inhibitory concentration (fT>MIC) of 4 μg/mL for ceftolozane and time that the unbound concentration exceeded the 1 μg/mL target threshold (fT>threshold = 1 µg/mL) for > 20% of the dosing interval for tazobactam. Safety was evaluated.

RESULTS

Mean (SD) area under the plasma concentration-time curve from 0 to infinity, clearance and volume of distribution at steady state (V_ss) were 236 (118) h*µg/mL, 10.4 (4.5) L/h and 30.8 (10.8) L, respectively, for ceftolozane; and 35.5 (18.5) h*µg/mL, 35.3 (16.5) L/h and 54.8 (20.1) L, respectively, for tazobactam. Clearance and V_ss were higher for both ceftolozane and tazobactam in patients with ARC compared with healthy individuals. The mean estimated ceftolozane fT>MIC at 4 µg/mL was 86.4%; the mean estimated tazobactam fT>threshold = 1 µg/mL was 54.9%. Treatment-emergent adverse events were mild to moderate.

CONCLUSIONS

In patients with ARC, a 3 g C/T dose met respective pharmacodynamic targets for ceftolozane and tazobactam. CLINICALTRIALS.

GOV IDENTIFIER

NCT02387372.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020)

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created as revised from J-SSCG 2016 jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in September 2020 and published in February 2021. An English-language version of these guidelines was created based on the contents of the original Japanese-language version. The purpose of this guideline is to assist medical staff in making appropriate decisions to improve the prognosis of patients undergoing treatment for sepsis and septic shock. We aimed to provide high-quality guidelines that are easy to use and understand for specialists, general clinicians, and multidisciplinary medical professionals. J-SSCG 2016 took up new subjects that were not present in SSCG 2016 (e.g., ICU-acquired weakness [ICU-AW], post-intensive care syndrome [PICS], and body temperature management). The J-SSCG 2020 covered a total of 22 areas with four additional new areas (patient- and family-centered care, sepsis treatment system, neuro-intensive treatment, and stress ulcers). A total of 118 important clinical issues (clinical questions, CQs) were extracted regardless of the presence or absence of evidence. These CQs also include those that have been given particular focus within Japan. This is a large-scale guideline covering multiple fields; thus, in addition to the 25 committee members, we had the participation and support of a total of 226 members who are professionals (physicians, nurses, physiotherapists, clinical engineers, and pharmacists) and medical workers with a history of sepsis or critical illness. The GRADE 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, 79 GRADE-based recommendations, 5 Good Practice Statements (GPS), 18 expert consensuses, 27 answers to background questions (BQs), and summaries of definitions and diagnosis of sepsis were created as responses to 118 CQs. We also incorporated visual information for each CQ according to the time course of treatment, and we will also distribute this as an app. The J-SSCG 2020 is expected to be widely used as a useful bedside guideline in the field of sepsis treatment both in Japan and overseas involving multiple disciplines.

Review of health economic models exploring and evaluating treatment and management of hospital-acquired pneumonia and ventilator-associated pneumonia

BACKGROUND

Hospital-acquired pneumonia (HAP) is pneumonia that occurs ≥48 h after hospital admission; it is the most common hospital-acquired infection contributing to death. Ventilator-associated pneumonia (VAP) arises ≥48-72 h after intubation. Opinions differ on whether VAP is a subset of HAP; the same pathogens predominate in both. Compared with VAP-free controls, patients developing VAP are twice as likely to die and have significantly longer stays in intensive care units. Guidelines recommend that microbiological cultures should guide antibiotic treatment, but these lack sensitivity and take 48-72 h to process, meaning that initial therapy must be empiric, generally with broad-spectrum agents. Given increasing pressure to improve both antibiotic stewardship and patient outcomes, the National Institute for Health and Care Excellence and the Infectious Diseases Society of America recommend research into rapid molecular diagnostic tests to identify causative organisms and their antibiotic resistances. Ideally, these would supersede culture, being quicker and more sensitive. In the UK, the INHALE research programme, funded by the National Institute for Health Research, is exploring rapid molecular diagnostics to inform treatment of HAP/VAP and, given resource implications, incorporates a health economic component.

AIM

To identify previous economic modelling of HAP/VAP costs to inform this component.

METHODS

Literature review of HAP/VAP studies with economic modelling identified from three databases.

FINDINGS

Twenty studies were identified. Only one study specifically evaluated strategies to improve diagnosis; the remaining 19 studies omitted this important aspect.

CONCLUSION

HAP/VAP modelling would be improved by better awareness of long-term outcomes and treatment complexity. To the authors' knowledge, no similar literature reviews of economic modelling for HAP/VAP have been published.

Update of the treatment of nosocomial pneumonia in the ICU

In accordance with the recommendations of, amongst others, the Surviving Sepsis Campaign and the recently published European treatment guidelines for hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP), in the event of a patient with such infections, empirical antibiotic treatment must be appropriate and administered as early as possible. The aim of this manuscript is to update treatment protocols by reviewing recently published studies on the treatment of nosocomial pneumonia in the critically ill patients that require invasive respiratory support and patients with HAP from hospital wards that require invasive mechanical ventilation. An interdisciplinary group of experts, comprising specialists in anaesthesia and resuscitation and in intensive care medicine, updated the epidemiology and antimicrobial resistance and established clinical management priorities based on patients' risk factors. Implementation of rapid diagnostic microbiological techniques available and the new antibiotics recently added to the therapeutic arsenal has been reviewed and updated. After analysis of the categories outlined, some recommendations were suggested, and an algorithm to update empirical and targeted treatment in critically ill patients has also been designed. These aspects are key to improve VAP outcomes because of the severity of patients and possible acquisition of multidrug-resistant organisms (MDROs).

Optimizing therapy of bloodstream infection due to extended-spectrum β-lactamase-producing Enterobacteriaceae

PURPOSE OF REVIEW

Infections due to extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) are increasing worldwide. Carbapenems are usually regarded as the antibiotics of choice for the treatment of serious ESBL infections. However, because of the alarming emergence or carbapenem resistance, interest in effective alternatives has emerged. The present review summarizes the findings published on the antibiotics currently available for treatment of patients with an ESBL-E bloodstream infection (BSI).

RECENT FINDINGS

Meropenem and imipenem are the drugs recommended for treatment of ESBL BSIs in critically ill patients, and in infections with high bacterial loads or elevated β-lactam minimum inhibitory concentrations. Ertapenem should be reserved for patients with less severe presentations, and should be used at high doses. In milder presentations or BSIs from low-risk sources, other carbapenem-sparing alternatives could be considered: cephamycins, fluoroquinolones, and particularly a β-lactam/β-lactam inhibitor combination (particularly piperacillin/tazobactam). Optimized dosing of piperacillin/tazobactam is recommended (high doses and extended infusion). There are few data on the use of the promising newly available drugs (e.g. ceftolozane/tazobactam, ceftazidime/avibactam, cefiderocol, and plazomicin), and it seems reasonable to reserve them as last-resort drugs.

SUMMARY

Carbapenems should be used in patients with serious infections; alternatives could be used individually, particularly for definitive treatment of patients with milder presentations.

Antimicrobial-associated harm in critical care: a narrative review

The belief that, for the individual patient, the benefit of prompt and continued use of antimicrobials outweighs any potential harm is a significant barrier to improved stewardship of these vital agents. Antimicrobial stewardship may be perceived as utilitarian rationing, seeking to preserve the availability of effective antimicrobials by limiting the development of resistance in a manner which could conflict with the immediate treatment of the patient in need. This view does not account for the growing evidence of antimicrobial-associated harm to individual patients. This review sets out the evidence for antimicrobial-associated harm and how this should be balanced with the need for prompt and appropriate therapy in infection. It describes the mechanisms by which antimicrobials may harm patients including: mitochondrial toxicity; immune cell toxicity; adverse drug reactions; selection of resistant organisms within a given patient; and disruption of the microbiome. Finally, the article indicates how the harms of antimicrobials may be mitigated and identifies areas for research and development in this field.

Epidemiology, Treatment, and Prevention of Nosocomial Bacterial Pneumonia

Septicaemia likely results in high case-fatality rates in the present multidrug-resistant (MDR) era. Amongst them are hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP), two frequent fatal septicaemic entities amongst hospitalised patients. We reviewed the PubMed database to identify the common organisms implicated in HAP/VAP, to explore the respective risk factors, and to find the appropriate antibiotic choice. Apart from methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa, extended-spectrum β-lactamase-producing Enterobacteriaceae spp., MDR or extensively drug-resistant (XDR)-Acinetobacter baumannii complex spp., followed by Stenotrophomonas maltophilia, Chryseobacterium indologenes, and Elizabethkingia meningoseptica are ranked as the top Gram-negative bacteria (GNB) implicated in HAP/VAP. Carbapenem-resistant Enterobacteriaceae notably emerged as an important concern in HAP/VAP. The above-mentioned pathogens have respective risk factors involved in their acquisition. In the present XDR era, tigecycline, colistin, and ceftazidime-avibactam are antibiotics effective against the Klebsiella pneumoniae carbapenemase and oxacillinase producers amongst the Enterobacteriaceae isolates implicated in HAP/VAP. Antibiotic combination regimens are recommended in the treatment of MDR/XDR-P. aeruginosa or A. baumannii complex isolates. Some special patient populations need prolonged courses (>7-day) and/or a combination regimen of antibiotic therapy. Implementation of an antibiotic stewardship policy and the measures recommended by the United States (US) Institute for Healthcare were shown to decrease the incidence rates of HAP/VAP substantially.

Evidence-Based Study Design for Hospital-Acquired Bacterial Pneumonia and Ventilator-Associated Bacterial Pneumonia

BACKGROUND

The US Food and Drug Administration solicited evidence-based recommendations to improve guidance for studies of hospital-acquired bacterial pneumonia (HABP) and ventilator-associated bacterial pneumonia (VABP).

METHODS

We analyzed 7 HABP/VABP datasets to explore novel noninferiority study endpoints and designs, focusing on alternatives to all-cause mortality (ACM).

RESULTS

ACM at day 28 differed for ventilated HABP (27.8%), VABP (18.0%), and nonventilated HABP (14.5%). A "mortality-plus" (ACM+) composite endpoint was constructed by combining ACM with patient-relevant, infection-related adverse events from the Medical Dictionary for Regulatory Activities toxic/septic shock standardized query. The ACM+ rate was 3-10 percentage points above that of ACM across the studies and treatment groups. Predictors of higher ACM/ACM+ rates included older age and elevated acute physiology and chronic health evaluation (APACHE) II score. Only patients in the nonventilated HABP group were able to report pneumonia symptom changes.

CONCLUSIONS

If disease groups and patient characteristics in future studies produce an ACM rate so low (<10%-15%) that a fixed noninferiority margin of 10% cannot be justified (requiring an odds ratio analysis), an ACM+ endpoint could lower sample size. Enrichment of studies with patients with a higher severity of illness would increase ACM. Data on symptom resolution in nonventilated HABP support development of a patient-reported outcome instrument.