Carbapenems vs. alternative β-lactams for the treatment of nosocomial pneumonia: A systematic review and meta-analysis

Empiric antibiotic regimens in adults with non-ventilator-associated hospital-acquired pneumonia: a systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

The optimal empiric antibiotic regimen for non-ventilator-associated hospital-acquired pneumonia (HAP) is uncertain.

OBJECTIVES

To compare the effectiveness and safety of alternative empiric antibiotic regimens in HAP using a network meta-analysis.

DATA SOURCES

Medline, EMBASE, Cochrane CENTRAL, Web of Science, and CINAHL from database inception to July 06, 2023.

STUDY ELIGIBILITY CRITERIA

RCTs.

PARTICIPANTS

Adults with clinical suspicion of HAP.

INTERVENTIONS

Any empiric antibiotic regimen vs. another, placebo, or no treatment.

ASSESSMENT OF RISK OF BIAS

Paired reviewers independently assessed risk of bias using a modified Cochrane tool for assessing risk of bias in randomized trials.

METHODS OF DATA SYNTHESIS

Paired reviewers independently extracted data on trial and patient characteristics, antibiotic regimens, and outcomes of interest. We conducted frequentist random-effects network meta-analyses for treatment failure and all-cause mortality and assessed the certainty of the evidence using the Grading of Recommendations Assessment, Development and Evaluation approach.

RESULTS

Thirty-nine RCTs proved eligible. Thirty RCTs involving 4807 participants found low certainty evidence that piperacillin-tazobactam (RR compared to all cephalosporins: 0.65; 95% CI: 0.42, 1.01) and carbapenems (RR compared to all cephalosporins: 0.77; 95% CI: 0.53, 1.11) might be among the most effective in reducing treatment failure. The findings were robust to the secondary analysis comparing piperacillin-tazobactam vs. antipseudomonal cephalosporins or antipseudomonal carbapenems vs. antipseudomonal cephalosporins. Eleven RCTs involving 2531 participants found low certainty evidence that ceftazidime and linezolid combination may not be convincingly different from cephalosporin alone in reducing all-cause mortality. Evidence on other antibiotic regimens is very uncertain. Data on other patient-important outcomes including adverse events was sparse, and we did not perform network or pairwise meta-analysis.

CONCLUSIONS

For empiric antibiotic therapy of adults with HAP, piperacillin-tazobactam might be among the most effective in reducing treatment failure. Empiric methicillin-resistant Staphylococcus aureus coverage may not exert additional benefit in reducing mortality.

REGISTRATION

PROSPERO (CRD 42022297224).

Carbapenems versus β-lactam and β-lactamase inhibitors for treatment of nosocomial pneumonia: A systematic review and meta-analysis

Background

Carbapenems and β-lactam and β-lactamase inhibitors (BLBLIs) have been used empirically in nosocomial pneumonia, but their efficacy and safety are controversial.

Objective

We carried out a systematic review with meta-analysis to evaluate the efficacy and safety of carbapenems versus BLBLIs against nosocomial pneumonia.

Methods

PubMed, Embase, Cochrane Central Register of Controlled Trials, CNKI, Wangfang, VIP and Sinomed were searched systematically through April 29, 2023 for clinical trials comparing carbapenems with BLBLIs for treatment of nosocomial pneumonia. Random-effects models were used to evaluate the impact of treatment on the risk ratio (RR) of all-cause mortality, clinical response, microbiologic response, resistance by Pseudomonas aeruginosa, adverse effects (AEs), and serious adverse effects. The quality of the evidence was assessed with the Cochrane risk of bias tool. The review was registerted in the INPLASY (INPLASY202340113).

Results

Seven randomized controlled trials containing 3306 patients met our inclusion criteria Our meta-analysis showed no significant difference in all-cause mortality (RR = 0.88, 95% confidence interval [CI] = 0.75-1.03, I2 = 0%) or clinical cure (1.02, 0.96-1.09, 30%) or clinical failure (1.19, 0.97-1.47, 0%) or microbiologic clinical cure (0.98, 0.89-1.06, 40%) or Pseudomonas aeruginosa resistance (RR 2.43, CI 0.86-6.81, 49%, P = 0.09) or adverse events (0.98, 0.93-1.02, 0%) between carbapenems groups versus BLBLIs groups, but a significant difference was found for severe adverse events (RR 0.83, CI 0.73-0.94, 0%).

Conclusion

Differences in the prevalence of mortality, clinical cure, or clinical failure were not observed between carbapenems groups versus BLBLIs groups in terms of nosocomial pneumonia. The use of carbapenems was linked to a tendency towards the emergence of P. aeruginosa resistance, however, no statistically significant difference was observed.

Cost-Effectiveness of Imipenem/Cilastatin/Relebactam Compared with Colistin in Treatment of Gram-Negative Infections Caused by Carbapenem-Non-Susceptible Organisms

INTRODUCTION

Imipenem/cilastatin/relebactam (IMI/REL), a combination β-lactam antibiotic (imipenem) with a novel β-lactamase inhibitor (relebactam), is an efficacious and well-tolerated option for the treatment of hospitalized patients with gram-negative (GN) bacterial infections caused by carbapenem-non-susceptible (CNS) pathogens. This study examines cost-effectiveness of IMI/REL vs. colistin plus imipenem (CMS + IMI) for the treatment of infection(s) caused by confirmed CNS pathogens.

METHODS

We developed an economic model comprised of a decision-tree depicting initial hospitalization, and a Markov model projecting long-term health and economic impacts following discharge. The decision tree, informed by clinical data from RESTORE-IMI 1 trial, modeled clinical outcomes (mortality, cure rate, and adverse events including nephrotoxicity) in the two comparison scenarios of IMI/REL versus CMS + IMI for patients with CNS GN infection. Subsequently, a Markov model translated these hospitalization stage outcomes (i.e., death or uncured infection) to long-term consequences such as quality-adjusted life years (QALYs). Sensitivity analyses were conducted to test the model robustness.

RESULTS

IMI/REL compared to CMS + IMI demonstrated a higher cure rate (79.0% vs. 52.0%), lower mortality (15.2% vs. 39.0%), and reduced nephrotoxicity (14.6% vs. 56.4%). On average a patient treated with IMI/REL vs. CMS + IMI gained additional 3.7 QALYs over a lifetime. Higher drug acquisition costs for IMI/REL were offset by shorter hospital length of stay and lower AE-related costs, which result in net savings of $11,015 per patient. Sensitivity analyses suggested that IMI/REL has a high likelihood (greater than 95%) of being cost-effective at a US willingness-to-pay threshold of $100,000-150,000 per QALY.

CONCLUSIONS

For patients with confirmed CNS GN infection, IMI/REL could yield favorable clinical outcomes and may be cost-saving-as the higher IMI/REL drug acquisition cost is offset by reduced nephrotoxicity-related cost-for the US payer compared to CMS + IMI.

The war against bacteria, from the past to present and beyond

INTRODUCTION

The human defense against microorganisms dates back to the ancient civilizations, with attempts to use substances from vegetal, animal, or inorganic origin to fight infections. Today, the emerging threat of multidrug-resistant bacteria highlights the consequences of antibiotics inappropriate use, and the urgent need for novel effective molecules.

METHODS AND MATERIALS

We extensively researched on more recent data within PubMed, Medline, Web of Science, Elsevier's EMBASE, Cochrane Review for the modern pharmacology in between 1987 - 2021. The historical evolution included a detailed analysis of past studies on the significance of medical applications in the ancient therapeutic field.

AREAS COVERED

We examined the history of antibiotics development and discovery, the most relevant biochemical aspects of their mode of action, and the biomolecular mechanisms conferring bacterial resistance to antibiotics.

EXPERT OPINION

The list of pathogens showing low sensitivity or full resistance to most currently available antibiotics is growing worldwide. Long after the 'golden age' of antibiotic discovery, the most novel molecules should be carefully reserved to treat serious bacterial infections of susceptible bacteria. A correct diagnostic and therapeutic procedure can slow down the spreading of nosocomial and community infections sustained by multidrug-resistant bacterial strains.

Antibacterial data synthesis challenges: a systematic review of treatments for complicated gram-negative urinary tract infections

Aim: To determine the suitability of network meta-analysis (NMA) using antibacterial treatment evidence in complicated urinary tract infection. Materials & methods: We conducted a systematic literature review to identify published clinical trial data for complicated urinary tract infection treatments. We performed a feasibility assessment to determine whether the available evidence would support the creation of a robust NMA, considering key assumptions of homogeneity, similarity and consistency. Results: Twenty-five trials met eligibility criteria. Risk of bias was low, and individual studies met their primary end point(s). Assumptions central to the conduct of a robust NMA were not met. Heterogeneity was ubiquitous, including baseline pathogen, treatment and patient characteristics. Conclusion: Limited and heterogeneous data identified make the use of NMA to compare novel antibacterial agents impractical and likely unreliable.

Antibiotic Treatment of Pulmonary Infections: An Umbrella Review and Evidence Map

Background: Considering the global burden of pulmonary infections, there is an urgent need for optimal empirical antimicrobial therapy strategies for pulmonary infections, which should rely on reliable evidence. Therefore, we aim to investigate the optimal treatment options for pulmonary infections in adults and assess the strength of that evidence. Methods: We searched PubMed, Embase, the Cochrane Library, and China Biology Medicine disc to identify systematic reviews and meta-analyses of randomized controlled trials (RCTs) focusing on antimicrobial treatments for pulmonary infections. The outcomes of the included meta-analyses should include all-cause mortality or clinical treatment success. For each meta-analysis, we estimated relative risk (RR) with 95% CI. We also created an evidence map to show the efficacy of each antimicrobial treatment strategy and the certainty of the evidence. Results: Twenty-six meta-analyses and two new RCTs were included that contained 31 types of antimicrobial therapy strategies. We found that carbapenems were related to lower mortality than other β-lactams or fluoroquinolones alone or in combination with aminoglycosides for HAP patients (RR 0.76, 95% CI: 0.58-0.99). There was no statistical difference in all-cause mortality between the other antimicrobial therapy strategies. As for clinical cure, treatment with fluoroquinolones was associated with better success versus macrolides or β-lactams alone for CAP patients in both the intention-to-treat (ITT) population (RR 1.22, 95% CI: 1.02-1.47) and clinically evaluable (CE) population (RR 1.37, 95% CI: 1.11-1.68). Treatment with carbapenems showed a better clinical cure over non-carbapenems for VAP patients (RR 1.21, 95% CI: 1.05-1.4). Adjunctive inhaled antibiotics compared with intravenous antibiotics alone showed a benefit for VAP (RR 1.2, 95% CI: 1.05-1.35). In addition, adjunctive nebulized aminoglycoside for nosocomial pneumonia was associated with a higher cure rate versus intravenous antibiotics alone in the ITT population (RR 1.28, 95% CI: 1.04-1.57), while no statistical difference in clinical cure was observed between other intervention groups. Conclusions: We cannot evaluate which antibiotic is the best choice for the treatment of pulmonary infection. Carbapenems or adjunctive inhaled antibiotics showed a reasonable choice for HAP or VAP. However, we do not find a statistical difference between most antimicrobial therapy strategies for CAP patients.

Pseudomonas aeruginosa necrotizing bronchopneumonia

Extremely low birth weight (ELBW) infants are at particularly high risk for infection due to an immature immune system, invasive procedures such as endotracheal intubation, intravascular catheterization, and other factors. Neonatal infections in this population are associated with a high mortality, poor growth, and neurodevelopmental outcomes. Pseudomonas aeruginosa (P. aeruginosa) infection is an uncommon but potentially devastating cause of pneumonia and sepsis in the ELBW population. P. aeruginosa is an important cause of healthcare-associated infections (HAI) or nosocomial infections. P. aeruginosa can perceive unfavorable environmental changes and orchestrate adaptations by developing plasmid-mediated and adaptive resistance to antibiotics. We describe an ELBW infant born at 26 weeks’ gestation who succumbed at 13 days of life to P. aeruginosa infection. Some of the factors related to the pathogenesis and multidrug resistance are described.

Systematic Literature Review of Real-world Evidence of Ceftolozane/Tazobactam for the Treatment of Respiratory Infections

Introduction

Gram-negative nosocomial pneumonia (NP), including hospital-acquired bacterial pneumonia (HABP), ventilated HABP (vHABP), and ventilator-associated bacterial pneumonia (VABP), is a significant cause of morbidity and mortality. Common pathogens, including Enterobacterales and Pseudomonas aeruginosa, are prevalent in healthcare settings and have few effective treatment options due to high rates of antibacterial resistance. Resistant pathogens are associated with significantly worse outcomes, relative to patients with susceptible infections. Ceftolozane/tazobactam (C/T) has established efficacy in clinical trials of patients with NP. This review aims to collate data on C/T use for HABP/vHABP/VABP infections in real-world clinical practice.

Methods

This systematic literature review searched online biomedical databases for real-world studies of C/T used to treat Gram-negative respiratory tract infections (RTIs) between January 2009 and June 2020.

Results

Thirty-three studies comprising 658 patients were identified. Pneumonia was the most common infection treated with C/T (85%), with a smaller number of unspecified RTIs (9%) and tracheobronchitis (5%) reported. The majority of patients had respiratory infections caused by P. aeruginosa (92.8%), of which 88.1% were multidrug-resistant. Examination of these studies demonstrated an increase in the percentage of patients receiving the recommended dose of C/T for respiratory infections (3 g q8h or renal impairment-adjusted) over time (36.8% of patients in 2017 to 71.5% in 2020). Clinical success rates ranged from 51.4 to 100%, with 10 studies (55.6% of studies reporting clinical success) reporting clinical success rates of > 70%; microbiological success rates ranged from 57.0 to 100.0%, with three studies (60.0% of studies reporting microbiological success) reporting microbiological success rates of > 70%. Thirty-day mortality ranged from 0.0 to 33.0%, with nine studies (90% of studies reporting mortality) reporting 30-day mortality of < 30%.

Conclusions

The studies identified in this review demonstrate that C/T shows similar outcomes as those seen in clinical trials, despite the higher frequency of multidrug-resistant pathogens, and comorbidities that may have been excluded from the trials.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40121-021-00491-x.

An evaluation of antipseudomonal dosing on the incidence of treatment failure

Introduction

Significant mortality is associated with delays in appropriate antibiotic therapy in Pseudomonas aeruginosa infections. The impact of empiric dosing on clinical outcomes has been largely unreported.

Methods

This retrospective cohort compared treatment failure in patients receiving guideline-concordant or guideline-discordant empiric therapy with cefepime, meropenem, or piperacillin/tazobactam. Patients with culture-positive P. aeruginosa between 1 July 2013 and 31 July 2019 were eligible for inclusion. Patients with cystic fibrosis, polymicrobial infection, and urinary or pulmonary colonization were excluded. The composite primary outcome was treatment failure, defined as (1) therapy modification due to resistance/perceived treatment failure, (2) increased/unchanged qSOFA, or (3) persistent fever 48 h after initiating appropriate therapy. Secondary outcomes included rate of infectious diseases consultation, all-cause inpatient mortality, mechanical ventilation requirement, and infection-related intensive care unit and hospital lengths of stay.

Results

In total, 198 patients were included: 90 guideline-concordant and 108 guideline-discordant. Baseline characteristics were balanced. Treatment failure was more common in the guideline-discordant than the guideline-concordant group (62% versus 48%; p = 0.04). This remained significant when adjusting for supratherapeutic dosing (p = 0.02). Infectious diseases consultation was higher in the guideline-discordant group (46% versus 29%, p = 0.01), while intensive care unit length of stay was longer in the guideline-concordant group (4.5 versus 3 days, p = 0.03). Additional secondary outcomes were similar.

Conclusion

Treatment failure was significantly higher in patients receiving guideline-discordant empiric antipseudomonal dosing. Guideline-directed dosing, disease states, and patient-specific factors should be assessed when considering empiric antipseudomonal dosing.

Comparison of ertapenem non-susceptibility with 2-mercaptopropionic acid phenotypic tests in predicting NDM-1 and IMP-1 production in clinical isolates of Escherichia coli

Background:

A routine phenotypic test has not been recommended for the detection of metallo-β-lactamases (MBLs) producing Enterobacteriaceae species such as Escherichia coli. The current study was conducted to compare the 2-mercaptopropionic acid (2-MPA) phenotypic method and ertapenem non-susceptibility test with polymerase chain reaction in predicting the production of MBLs in clinical isolates of E. coli.

Methods:

Antimicrobial susceptibility test for beta-lactam antibiotics were performed by disk diffusion method. All isolates which showed inhibition zones of ≤ 22 mm for CAZ and ≤ 27 mm for CTX were considered potential MBLs producing isolates. The production of MBLs was confirmed using 2-MPA compound. Also, susceptibility to ertapenem was evaluated in all isolates. Conventional PCR was performed to detect blaIMP-1 and/or blaNDM-1 genes in all potential MBLs producing E. coli isolates.

Results:

Of 259, 138 (53.3%) isolates were potential MBLs producing bacteria. One hundred and fifteen out of 138 (83.3%) isolates were susceptible to ertapenem. MBLs production was confirmed in 75/138 (54.4%) isolates by 2-MPA phenotypic method. The blaNDM-1 or/and blaIMP-1 genes were found in 30/75(40%) and 39/115(33.9%) isolates which were confirmed by 2-MPA and were susceptible to ertapenem, respectively. The sensitivity of 2-MPA method and ertapenem non-susceptibility test compared with PCR were 65.2% and 15.2%, and the specificity was 52.1% versus 82.6%, respectively.

Conclusion:

This study demonstrated that the 2-MPA phenotypic method does not have acceptable sensitivity and specificity in comparison with PCR, but its results are more reliable for the detection of MBL producing E. coli isolates compared with non-susceptibility to ertapenem.

Carbapenem Antibiotics for the Empiric Treatment of Nosocomial Pneumonia: A Systematic Review and Meta-analysis

BACKGROUND

Previous meta-analyses suggested that treating hospital-acquired pneumonia (HAP), including ventilator-associated pneumonia (VAP), with empiric carbapenems was associated with lower mortality rates but higher rates of clinical failure for pseudomonal pneumonia. This study was an updated meta-analysis with sensitivity analyses and meta-regression to better understand the impact of carbapenem use in HAP/VAP.

RESEARCH QUESTION

What is the efficacy of carbapenems for empiric treatment of nosocomial pneumonia?

STUDY DESIGN AND METHODS

Databases were searched for randomized controlled studies evaluating empiric treatment for HAP and/or VAP, and studies were included comparing carbapenem- vs non-carbapenem-containing regimens. The primary outcome was all-cause mortality. Secondary outcomes included subgroup stratification and resistance development.

RESULTS

Of 9,140 references, 20 trials enrolling 5,489 patients met inclusion criteria. For mortality, carbapenem use had a risk ratio (RR) of 0.84 (95% CI, 0.74-0.96; P = .01). Stratified according to VAP proportion (< 33%, 33%-66%, and > 66%), RRs were 0.95 (95% CI, 0.77-1.17; P = .66), 0.78 (95% CI, 0.57-1.07; P = .13), and 0.81 (95% CI, 0.65-0.99; P = .04), respectively. Stratified according to severity, only groups with Acute Physiology and Chronic Health Evaluation II scores < 14 and between 14 and 17 showed mortality benefit (RRs of 0.64 [95% CI, 0.45-0.92; P = .01] and 0.77 [95% CI, 0.61-0.97; P = .03]). Meta-regression did not show an association between Pseudomonas prevalence and mortality (P = .44). Carbapenem use showed a trend toward developing resistance (RR, 1.40; 95% CI, 0.95-2.06; P = .09) and a 96% probability of resistance emergence.

INTERPRETATION

Carbapenem-based empiric regimens were associated with lower mortality rates compared with non-carbapenems, largely driven by trials of VAP. The mortality effect was not observed in trials with high disease severity and was not associated with Pseudomonas. The mortality difference was observed mainly in studies that used ceftazidime as control. There was a trend toward increasing resistance associated with carbapenems.

TRIAL REGISTRY

International Prospective Register of Systematic Reviews; No. CRD42018093602; URL: https://www.crd.york.ac.uk/prospero/.

Approach to the Treatment of Patients with Serious Multidrug-Resistant Pseudomonas aeruginosa Infections

Multidrug resistance(MDR) among Pseudomonas aeruginosa (PSA) isolates presents a significant clinical challenge and can substantially complicate the approach to selection of optimal antibiotic therapy. This review addresses major considerations in antibiotic selection for patients with suspected or documented serious MDR-PSA infections. Common mechanisms contributing to MDR among clinical PSA isolates are summarized. Empiric and definitive therapy considerations are addressed including the potential role of combination therapy. Newer agents with in vitro activity against MDR-PSA (e.g., ceftolozane-tazobactam, ceftazidime-avibactam, imipenem-relebactam, and cefiderocol) and their potential roles in clinical settings are discussed. Although these newer agents are promising options for the treatment of MDR-PSA, clinical data remain generally limited. Future studies are needed to determine optimal agents for the empiric and definitive treatment of MDR-PSA.

Characterize carbapenem-resistant Klebsiella pneumoniae isolates for nosocomial pneumonia and their Gram-negative bacteria neighbors in the respiratory tract

This study was conducted to perform an epidemiological survey of carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates for nosocomial pneumonia (NP) and visit their Gram-negative bacteria neighbors (GNNs) from the respiratory tracts. Pulsed-field gel electrophoresis and multi locus sequence typing were performed to evaluate the clonal relationships of these isolates. Statistical methods were then used to understand their possible relationship between CRKP and their GNNs. Among the 63 CRKP isolates, 84.1% produced a KPC-2 carbapenemase gene, followed by blaNDM-1 and blaIMP-38 like. 13 different STs and 29 clones were identified. Less heterogeneous clone backgrounds were observed in 53 KPC-2 K. pneumoniae isolates, and 6 STs have been found to contain KPC-2, of which the predominant ST11 harbored 47 KPC-2-producing K. pneumoniae isolates. Particularly, the two infrequent isolates co-possessing blaKPC-2 and blaIMP-38 like shared a different clonal relationship. 87 GNNs isolates of CRKP were established, the analysis present that different strains showed significant or no difference with CRKP upon antibiotics susceptibility. Conclusion, ST11 harboring KPC-2-producing K. pneumoniae isolates were dominant for NP, and both clonal spread and horizontal transfer contributed to the dissemination of CRKP. However, additional studies are needed to explore the biological relationship with their GNNs.