Efficacy of Ceftazidime-Avibactam Versus Polymyxin B and Risk Factors Affecting Clinical Outcomes in Patients With Carbapenem-Resistant Klebsiella pneumoniae Infections a Retrospective Study

Ceftazidime/avibactam versus polymyxin B in carbapenem-resistant Klebsiella pneumoniae infections: a propensity score-matched multicenter real-world study

OBJECTIVES

In this retrospective observational multicenter study, we aimed to assess efficacy and mortality between ceftazidime/avibactam (CAZ/AVI) or polymyxin B (PMB)-based regimens for the treatment of Carbapenem-resistant Klebsiella pneumoniae (CRKP) infections, as well as identify potential risk factors.

METHODS

A total of 276 CRKP-infected patients were enrolled in our study. Binary logistic and Cox regression analysis with a propensity score-matched (PSM) model were performed to identify risk factors for efficacy and mortality.

RESULTS

The patient cohort was divided into PMB-based regimen group (n = 98, 35.5%) and CAZ/AVI-based regimen group (n = 178, 64.5%). Compared to the PMB group, the CAZ/AVI group exhibited significantly higher rates of clinical efficacy (71.3% vs. 56.1%; p = 0.011), microbiological clearance (74.7% vs. 41.4%; p < 0.001), and a lower incidence of acute kidney injury (AKI) (13.5% vs. 33.7%; p < 0.001). Binary logistic regression revealed that the treatment duration independently influenced both clinical efficacy and microbiological clearance. Vasoactive drugs, sepsis/septic shock, APACHE II score, and treatment duration were identified as risk factors associated with 30-day all-cause mortality. The CAZ/AVI-based regimen was an independent factor for good clinical efficacy, microbiological clearance, and lower AKI incidence.

CONCLUSIONS

For patients with CRKP infection, the CAZ/AVI-based regimen was superior to the PMB-based regimen.

Retrospective Tertiary Care-Based Cohort Study on Clinical Characteristics and Outcomes of Ceftazidime-Avibactam-Resistant Carbapenem-Resistant Klebsiella pneumoniae Infections

Introduction

The advent of ceftazidime-avibactam (CAZ-AVI)-resistant carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates has been steadily documented in recent years. We aimed to identify risk factors of CAZ-AVI-resistant CRKP infection and assess clinical outcomes of patients.

Methods

The study retrospectively examined the clinical and microbiological data of patients with ceftazidime avibactam susceptible and ceftazidime avibactam-resistant Klebsiella pneumonia carbapenem-resistant enterobacteriaceae infection to identify risk factors, clinical features, and outcomes using multivariate logistic regression analysis.

Results

A total of 152 patients with CRKP infection were enrolled in this study. Patients with CAZ-AVI-resistant CRKP isolates (20/34 = 58.8%) had prior exposure to carbapenems (p=0.003) and had more tracheostomies (16/34 = 47.1%) (p=0.001). Only 8/28 (28.6%) patients with CAZ-AVI susceptible CRKP isolates died amongst those administered ceftazidime-avibactam compared to 49/90 (54.4%) who did not receive the same (p=0.016). 1/9 (11.1%) patients with CAZ-AVI-resistant CRKP isolates who received colistin died compared to 13/25 (52%) who did not receive colistin (p=0.03). There was no association between presence of CAZ-AVI-resistant CRKP isolates and overall mortality (odds ratio: 0.7; 95% CI: 0.3, 1.6), and no independent predictors of risk factors to overall mortality in the group with CAZ-AVI-resistant CRKP isolates were noted.

Conclusion

Early advent of CAZ-AVI resistance in CRE isolates highlights the dynamic necessity of routine CAZ-AVI resistance laboratory testing and antimicrobial stewardship programmes focusing on the utilization of all antibiotics. Consolidating the hospital infection control of tracheostomies may help to prevent CAZ resistance in CRKP. Colistin may aid in decreasing of mortality rates among patients with CAZ-AVI CRKP isolates.

Ceftazidime-Avibactam in the Treatment of Patients with Bacteremia or Nosocomial Pneumonia: A Systematic Review and Meta-analysis

INTRODUCTION

Ceftazidime-avibactam (CAZ-AVI) is a combination of the third-generation cephalosporin ceftazidime and the novel, non-β-lactam β-lactamase inhibitor avibactam that is approved for the treatment of pediatric (≥ 3 months) and adult patients with complicated infections including hospital-acquired and ventilator-associated pneumonia (HAP/VAP), and bacteremia. This systematic literature review and meta-analysis (PROSPERO registration: CRD42022362856) aimed to provide a quantitative and qualitative synthesis to evaluate the effectiveness of CAZ-AVI in treating adult patients with bacteremia or nosocomial pneumonia caused by carbapenem-resistant Enterobacterales (non metallo-β-lactamase-producing strains) and multi-drug resistant (MDR) Pseudomonas aeruginosa infections.

METHODS

The databases included in the search, until November 7, 2022, were Embase and PubMed. A total of 24 studies (retrospective: 22, prospective: 2) with separate outcomes for patients with bacteremia or pneumonia were included.

RESULTS

The outcomes assessed were all-cause mortality, clinical cure, and microbiological cure. Qualitative (24 studies) and quantitative (8/24 studies) syntheses were performed. The quality of the studies was assessed using the MINORS checklist and the overall risk of bias was moderate to high.

CONCLUSIONS

In studies included in the meta-analysis, lower all-cause mortality for patients with bacteremia (OR = 0.30, 95% CI 0.19-0.46) and improved rates of clinical cure for patients with bacteremia (OR = 4.90, 95% CI 2.60-9.23) and nosocomial pneumonia (OR = 3.20, 95% CI 1.55-6.60) was observed in the CAZ-AVI group compared with the comparator group. Data provided here may be considered while using CAZ-AVI for the treatment of patients with difficult-to-treat infections.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42022362856.

Efficiency of polymyxin B treatment against nosocomial infection: a systematic review and meta-analysis

Background

Some cohort studies have explored the effects and safety of polymyxin B (PMB) in comparison to other antibiotics for the treatment of nosocomial infections, yielding inconsistent results. This systematic review aims to explore the effectiveness and safety of PMB and compared it with other antibiotics.

Methods

A systematic literature search was conducted in PubMed, Embase, the Cochrane Library, and Web of Science, searching specific terms to identify quantitative cohort studies or RCTs that compared the effects of PMB with other antibiotics in terms of their efficacy and safety. The Newcastle-Ottawa Scale (NOS) was conducted to evaluate the risk of bias of observational studies. Odds ratios with 95% confidence intervals were used for outcome assessment. We evaluated heterogeneity using the I 2 test.

Results

A total of 22 observational trials were included in the analysis. The PMB group had a higher mortality rate compared to the control group (odds ratio: 1.84, 95% CI: 1.36-2.50, p<0.00001, I 2 = 73%). while, the ceftazidime-avibactam group demonstrated a distinct advantage with lower mortality rates, despite still exhibiting high heterogeneity (odds ratio 2.73, 95% confidence interval 1.59-4.69; p = 0.0003; I 2 = 53%). Additionally, the PMB group had a lower nephrotoxicity rate compared to the colistin group but exhibited high heterogeneity in the results (odds ratio 0.58, 95% CI 0.36-0.93; p = 0.02; I 2 = 73%).

Conclusion

In patients with nosocomial infections, PMB is not superior to other antibiotics in terms of mortality, specifically when compared to ceftazidime-avibactam. However, PMB demonstrated an advantage in terms of nephrotoxicity compared to colistin.

Clinical outcomes and risk factors for mortality in recipients with carbapenem-resistant gram-negative bacilli infections after kidney transplantation treated with ceftazidime-avibactam: a retrospective study

Background

Ceftazidime-avibactam is a treatment option for carbapenem-resistant gram-negative bacilli (CR-GNB) infections. However, the risk factors associated with ceftazidime-avibactam (CAZ-AVI) treatment failure in kidney transplant (KT) recipients and the need for CAZ-AVI-based combination therapy remain unclear.

Methods

From June 2019 to December 2023, a retrospective observational study of KT recipients with CR-GNB infection treated with CAZ-AVI was conducted, with the primary outcome being 30-day mortality and secondary outcomes being clinical cure, microbiological cure, and safety. Risk factors for 30-day mortality and clinical failure were also investigated.

Results

A total of 81 KT recipients treated with CAZ-AVI were included in this study. Forty recipients (49.4%) received CAZ-AVI monotherapy, with a 30-day mortality of 22.2%. The clinical cure and microbiological cure rates of CAZ/AVI therapy were 72.8% and 66.7%, respectively. CAZ-AVI alone or in combination with other medications had no effect on clinical cure or 30-day mortality. Multivariate logistic regression analysis revealed that a higher Acute Physiology and Chronic Health Evaluation (APACHE) II score (odds ratio [OR]: 4.517; 95% confidence interval [CI]: 1.397-14.607; P = 0.012) was an independent risk factor for 30-day mortality. Clinical cure was positively associated with the administration of CAZ-AVI within 48 hours of infection onset (OR: 11.009; 95% CI: 1.344-90.197; P=0.025) and negatively associated with higher APACHE II scores (OR: 0.700; 95% CI: 0.555-0.882; P=0.002). Four (4.9%) recipients experienced recurrence within 90 days after the initial infection, 3 (3.7%) recipients experienced CAZ-AVI-related adverse events, and no CAZ-AVI resistance was identified.

Conclusion

CAZ-AVI is an effective medication for treating CR-GNB infections following kidney transplantation, even as monotherapy. Optimization of CAZ/AVI therapy (used within 48 hours of infection onset) is positively associated with potential clinical benefit. Further larger-scale studies are needed to validate these findings.

Ceftazidime-avibactam alone or in combination with Aztreonam versus Polymyxins in the management of carbapenem-Resistant Klebsiella pneumoniae nosocomial Infections (CAPRI study): a retrospective cohort study from South India

INTRODUCTION

Carbapenem-resistant Klebsiella pneumoniae (CRKP) infections commonly cause hospital-acquired infections. The study aimed to compare the outcomes of CRKP infections between patients receiving ceftazidime avibactam +/- aztreonam and polymyxins in a hospital setting with a high prevalence of New Delhi Metallo Beta Lactamase production.

METHODS

We conducted a retrospective cohort study from January 2020 to September 2022 in critically ill adult patients admitted to a non-COVID-19 medical intensive care unit with CRKP infection. The patients were followed up for a total of 30 days or death, whichever was later.

RESULTS

Of a total of 106 patients included in the study, 65 patients received polymyxins and 41 patients received ceftazidime-avibactam +/- aztreonam. Higher 30-day mortality was noted in the polymyxin group (56.9% vs. 29.2%, P = 0.005). The mean time to event (mortality) in ceftazidime-avibactam +/- aztreonam was 23.9 + 1.5 days which was significantly higher compared to polymyxins (17.9 + 1.2 days, p = 0.006). On Cox regression analysis, after adjusting for the covariates, the hazard ratio for time to event with the use of polymyxin was 2.02 (95% CI: 1.03-3.9).

CONCLUSION

Ceftazidime-avibactam + aztreonam is possibly associated with better clinical outcomes in patients infected with CRKP.

Ceftazidime-avibactam versus polymyxins in treating patients with carbapenem-resistant Enterobacteriaceae infections: a systematic review and meta-analysis

OBJECTIVE

Carbapenem-resistant Enterobacteriaceae (CRE) pose a significant threat to human health and have emerged as a major public health concern. We aimed to compare the efficacy and the safety of ceftazidime-avibactam (CAZ-AVI) and polymyxin in the treatment of CRE infections.

METHODS

A systematic review and meta-analysis was performed by searching the databases of EMBASE, PubMed, and the Cochrane Library. Published studies on the use of CAZ-AVI and polymyxin in the treatment of CRE infections were collected from the inception of the database until March 2023. Two investigators independently screened the literature according to the inclusion and exclusion criteria, evaluated the methodological quality of the included studies and extracted the data. The meta-analysis was performed using RevMan 5.4 software.

RESULTS

Ten articles with 833 patients were included (CAZ-AVI 325 patients vs Polymyxin 508 patients). Compared with the patients who received polymyxin-based therapy, the patients who received CAZ-AVI therapy had significantly lower 30-days mortality (RR = 0.49; 95% CI 0.01-2.34; I2 = 22%; P < 0.00001), higher clinical cure rate (RR = 2.70; 95% CI 1.67-4.38; I2 = 40%; P < 0.00001), and higher microbial clearance rate (RR = 2.70; 95% CI 2.09-3.49; I2 = 0%; P < 0.00001). However, there was no statistically difference in the incidence of acute kidney injury between patients who received CAZ-AVI and polymyxin therapy (RR = 1.38; 95% CI 0.69-2.77; I2 = 22%; P = 0.36). In addition, among patients with CRE bloodstream infection, those who received CAZ-AVI therapy had significantly lower mortality than those who received polymyxin therapy (RR = 0.44; 95% CI 0.27-0.69, I2 = 26%, P < 0.00004).

CONCLUSIONS

Compared to polymyxin, CAZ-AVI demonstrated superior clinical efficacy in the treatment of CRE infections, suggesting that CAZ-AVI may be a superior option for CRE infections.

Clinical Outcomes and Risk Factors for Death in Critically Ill Patients with Carbapenem-Resistant Klebsiella pneumoniae Treated with Ceftazidime-Avibactam: A Retrospective Study

Purpose

Carbapenem-Resistant Klebsiella pneumoniae (CRKP) is a significant public health threat, because it is associated with substantial morbidity and mortality. However, the risk factors associated with treatment failure of ceftazidime-avibactam (CAZ-AVI) and the need for CAZ-AVI-based combination remain unclear.

Methods

We conducted a retrospective study of critically ill patients (age: > 18 years) diagnosed with CRKP infections and treated with CAZ-AVI for at least 24 h between June 2020 and December 2022 at Henan Provincial People's Hospital.

Results

This study included a total of 103 patients who received CAZ-AVI. Of these, 91 (88.3%) patients received the standard dosage of 2.5 g every q8h, while only 20 (19.4%) received monotherapy. The Kaplan-Meier curves showed that the all-cause 30-day mortality was significantly higher among patients who experienced septic shock than those who did not. There was no significant difference in mortality between monotherapy and combination therapy. Dose reduction of CAZ-AVI was associated with a significantly increased mortality rate. Independent risk factors for the 30-day mortality included higher APACHE II score (HR: 1.084, 95% CI: 1.024-1.147, p = 0.005) and lower lymphocyte count (HR: 0.247, 95% CI: 0.093-0.655, p = 0.005). Conversely, a combination therapy regimen containing carbapenems was associated with lower mortality (HR: 0.273, 95% CI: 0.086-0.869, p = 0.028).

Conclusion

Our study suggests that CAZ-AVI provides clinical benefits in terms of survival and clinical response in critically ill patients with CRKP infection. A higher APACHE II score and lower lymphocyte count were associated with 30-day mortality, while the combination therapy regimen containing carbapenems was the only protective factor. CAZ-AVI dose reduction was associated with an increased mortality rate. Futher large-scale studies are needed to validate these findings.

Reviewing novel treatment options for carbapenem-resistant Enterobacterales

INTRODUCTION

Carbapenem resistant Enterobacterales (CRE) are a major threat to global health and hospital-onset CRE infections have risen during the COVID-19 pandemic. Novel antimicrobials are now available for the treatment of CRE infections. There remains an urgent need for new antimicrobials for CRE, especially for those producing metallo-β-lactamases.

AREAS COVERED

This article discusses previously published research supporting currently available novel antimicrobials for the treatment of CRE infections. Newer compounds currently being evaluated in clinical trials are covered. A literature search was conducted in PubMed over all available dates for relevant published papers and conference abstracts with the search terms, 'CRE,' 'carbapenem-resistant Enterobacterales,' 'β-lactam-β-lactamase inhibitor,' 'KPC,' 'NDM,' 'metallo-β-lactamase,' 'ceftazidime-avibactam,' 'meropenem-vaborbactam,' 'imipenem-cilastatin-relebactam,' 'cefiderocol,' 'eravacycline,' 'plazomicin,' 'taniborbactam,' 'zidebactam,' and 'nacubactam.'

EXPERT OPINION

Novel antimicrobials for CRE infections have been developed, most notably the β-lactam-β-lactamase inhibitor combinations, though treatment options for infections with metallo-β-lactamase producing Enterobacterales remain few and have limitations. Development of antibiotics with activity against metallo-β-lactamase producing Enterobacterales is eagerly awaited, and there are promising new compounds in clinical trials. Finally, more clinical research is needed to optimize and individualize treatment approaches, which will help guide antimicrobial stewardship initiatives aimed at reducing the spread of CRE and development of further resistance.

Risk Factors and Mortality of Elderly Patients with Hospital-Acquired Pneumonia of Carbapenem-Resistant Klebsiella pneumoniae Infection

Purpose

Hospital-acquired pneumonia (HAP) caused by carbapenem-resistant K. pneumoniae (CRKP), especially in elderly patients, results in high morbidity and mortality. Studies on risk factors, mortality, and antimicrobial susceptibility of CRKP pulmonary infection among elderly patients are lacking.

Patients and Methods

A retrospective case-control study was conducted from January 2019 to December 2021. The elderly inpatients (≥65 years) who were diagnosed with HAP caused by K. pneumoniae were enrolled. Clinical data were collected. Univariate and multivariate logistic regression analyses were used to identify risk factors. Propensity score matching was used to minimize the effect of potential confounding variables. Kaplan-Meier analysis was used to compare survival.

Results

A total of 115 patients with CRKP infection and 78 patients with carbapenem-susceptible K. pneumoniae (CSKP) infection were recruited. There were four independent risk factors for CRKP infection: history of intensive care unit (ICU) stays from hospital admission to positive respiratory specimen culture for K. pneumoniae (odds ratio (OR)=2.530), Charlson comorbidity index score ≥3 (OR = 2.420), prior exposure to carbapenems (OR = 5.280), and prior K. pneumoniae infection or colonization in the preceding 3 years (OR = 18.529). The all-cause 30-day mortality was 22.3%, the mortality of CRKP and CSKP infection was 28.7% and 12.8%, respectively. Independent risk factors for mortality included: older age (OR = 1.107), immunocompromised patients (OR = 8.632), severe pneumonia (OR = 51.244), quick Sepsis-related Organ Failure Assessment (qSOFA) score ≥2 (OR = 6.187), exposure to tigecycline before infection (OR = 24.702), and prolonged ICU stay (OR = 0.987). Thirty-day mortality was significantly lower in patients receiving ceftazidime-avibactam (CAZ-AVI) containing regimens than patients receiving polymyxin B sulfate (PB) containing regimens (P = 0.048). qSOFA score had a good prognostic effect [area under receiver operating characteristic curve (AUROC) of 0.838].

Conclusion

Active screening of CRKP for the high-risk populations, especially elderly patients, is significant for early detection and successful management of CRKP infection.

Clinical, biological and genome-wide comparison of carbapenem-resistant Klebsiella pneumoniae with susceptibility transformation to polymyxin B during therapy

OBJECTIVES

The emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) is a major clinical concern, and polymyxin B (PMB) is a 'last resort' antibiotic for its treatment. Understanding the effects of drug susceptibility transformation in CRKP-infected patients undergoing PMB treatment would be beneficial to optimize PMB treatment strategies.

METHODS

We retrospectively collected data from patients infected with CRKP and treated with PMB from January 2018 to December 2020. CRKPs were collected before and after PMB therapy, and patients were classified into the 'transformation' group (TG) and 'non-transformation' group (NTG) by the shift of susceptibility to PMB. We compared clinical characteristics between these groups, and further analysed the phenotypic and genome variation of CRKP after PMB susceptibility transformation.

RESULTS

A total of 160 patients (37 in the TG and 123 in the NTG) were included in this study. The duration of PMB treatment before PMB-resistant K. pneumoniae (PRKP) appearance in TG was even longer than the whole duration of PMB treatment in NTG (8 [8] vs. 7 [6] days; p 0.0496). Compared with isogenic PMB-susceptible K. pneumoniae (PSKP), most PRKP strains had missense mutations in mgrB (12 isolates), yciC (10 isolates) and pmrB (7 isolates). The competition index of 82.4% (28/34) of PRKP/PSKP pairs was <67.6% (23/34), and 73.5% (25/34) of PRKP strains showed a higher 7-day lethality in Galleria mellonella and a greater ability to resist complement-dependent killing than their corresponding PSKP, respectively.

CONCLUSION

Low dose with longer PMB treatment durations may be associated with the emergence of polymyxin resistance. The evolution of PRKP is predominantly mediated by an accumulation of mutations, including those in mgrB, yciC, and pmrB. Lastly, PRKP exhibited reduced growth and increased virulence compared with parental PSKP.

Risk factors and clinical outcomes of carbapenem-resistant Klebsiella pneumoniae bacteraemia in children: a retrospective study

OBJECTIVES

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is increasingly being identified in children, but data on the clinical outcomes in this population are limited. This study aimed to characterise the risk factors for 30-day mortality with CRKP bloodstream infection (BSI) in children.

METHODS

A retrospective study was performed from January 2018 to December 2021 at the First Affiliated Hospital of Zhengzhou University. Patients aged < 18 years and with CRKP BSI were included. Multivariable Cox and logistic regression were performed to determine risk factors for death and the development of septic shock following CRKP infection, respectively.

RESULTS

This study identified 33 neonates aged 0-4 weeks and 37 older children. The 30-day mortality rate was 39.4% in neonates and 43.2% in older children. In the neonatal population, a higher Pitt bacteremia score (HR 1.694; 95% CI 1.313-2.186; P < 0.001) was an independent risk factor for 30-day mortality. In the non-neonatal population, higher platelet count (HR 0.990; 95% CI 0.982-0.998; P = 0.010), the use of carbapenems (HR 0.212; 95% CI 0.064-0.702; P = 0.011) and appropriately targeted antimicrobial treatment (HR 0.327; 95% CI 0.111-0.969; P = 0.044) were associated with decreased 30-day mortality. Monocyte count < 0.1 × 109 cells/L (OR 3.615; 95% CI 1.165-11.444; P = 0.026) and a higher Pitt bacteremia score (OR 1.330; 95% CI 1.048-1.688; P = 0.019) were identified as risk factors for the development of septic shock.

CONCLUSIONS

Carbapenem-resistant Klebsiella pneumoniae BSI was associated with high mortality in children. Appropriate antimicrobial treatment is important to improve survival, but more work is needed to assess the efficacy of specific treatment regimens in children.

Ceftazidime-avibactam with or without Aztreonam vs Polymyxin-based Combination Therapy for Carbapenem-resistant Enterobacteriaceae: A Retrospective Analysis

Introduction

Gram-negative sepsis remains one of the most difficult to treat infections in intensive care units (ICUs). Carbapenems are often considered to be robust and reliable options for treating infections due to Gram-negative bacteria. The dominance of carbapenem-resistant enterobacteriaceae (CRE) has emerged as one of the greatest challenges faced by the medical community today. Carbapenem-resistant enterobacteriaceae may be resistant to all beta lactam antimicrobials including carbapenems and often, are even resistant to other classes of drugs. There are limited studies comparing polymyxin-based therapies with ceftazidime-avibactam (CAZ-AVI)-based therapies for treating infections caused by CRE.

Methods

A retrospective study comparing outcomes between patients with bacteremia caused by CRE treated with polymyxin-based combination therapy and CAZ-AVI-based therapy (with or without aztreonam).

Results

Of total 104 patients, 78 (75%) were in the CAZ-AVI group. There was no significant difference in the underlying comorbidities between the two groups. The incidence of nephrotoxicity was significantly higher in the polymyxin group (p = 0.017). Ceftazidime-avibactam-based therapy was 66% less likely to be associated with day 14 mortality (p = 0.048) and 67% less likely to be associated with day 28 mortality (p = 0.039) as compared with polymyxin-based therapy.

Conclusion

Ceftazidime-avibactam-based therapy may be a superior option to polymyxin-based therapy for infections caused by CRE. This can have significant practical applications, in terms of optimizing therapy for the individual patient as well as sparing polymyxins and reducing the use of polymyxins in our hospitals.

How to cite this article

Prayag PS, Patwardhan SA, Panchakshari S, Sambasivam R, Dhupad S, Soman RN, et al. Ceftazidime-avibactam with or without Aztreonam vs Polymyxin-based Combination Therapy for Carbapenem-resistant Enterobacteriaceae: A Retrospective Analysis. Indian J Crit Care Med 2023;27(6):444-450.

Efficacy and safety of ceftazidime-avibactam versus polymyxins in the treatment of carbapenem-resistant Enterobacteriaceae infection: a systematic review and meta-analysis

OBJECTIVES

Carbapenem-resistant Enterobacteriaceae is increasingly recognised as a significant public health concern. Ceftazidime-avibactam (CAZ-AVI) and polymyxins are considered as the last therapeutic options worldwide. This is the first meta-analysis of recently published data to compare the clinical efficacy and safety of CAZ-AVI with polymyxins in the treatment of carbapenem-resistant Enterobacteriaceae infections.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, Embase and the Cochrane Library were systematically searched, for publications in any language, from database inception to February 2023.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies comparing the clinical efficacy and safety of CAZ-AVI with polymyxins were included. Mortality, clinical success, microbiological eradication and nephrotoxicity were assessed as the main outcomes.

DATA EXTRACTION AND SYNTHESIS

Literature screening, data extraction and the quality evaluation of studies were conducted by two researchers independently, with disagreements resolved by another researcher. The Newcastle-Ottawa Scale was used to assess the bias risk for the included studies. Review Manager V.5.3 was employed for the meta-analysis.

RESULTS

The meta-analysis included seven retrospective and four prospective cohort studies with 1111 patients enrolled. The CAZ-AVI groups demonstrated a lower 30-day mortality (risk ratio (RR)=0.48, 95% CI of 0.37 to 0.63, I²=10%, p<0.0001) in nine studies with 766 patients; higher clinical success (RR=1.71, 95% CI 1.33 to 2.20, I²=35%, p<0.0001) in four studies with 463 patients; and lower nephrotoxicity in seven studies with 696 patients (RR=0.42, 95% CI 0.23 to 0.77, I²=35%, p<0.05). However, no significant difference in microbiological eradication rates was observed in 249 patients from two studies (RR=1.16, 95% CI 0.97 to 1.39, I²=0, p>0.05).

CONCLUSION

Available evidence suggested that CAZ-AVI treatment held a dominant position with respect to efficacy and safety compared with polymyxins in carbapenem-resistant Enterobacteriaceae infections. However, the analysis included only observational studies, and high-quality, large-scale, multicentre, double-blind randomised controlled trials are needed to confirm the advantage of CAZ-AVI.

Efficacy and mortality of ceftazidime/avibactam-based regimens in carbapenem-resistant Gram-negative bacteria infections: A retrospective multicenter observational study

OBJECTIVES

Limited data on clinical and microbiological efficacy, patient mortality, and other associated factors are available for ceftazidime/avibactam (CAZ/AVI)-based regimens for carbapenem-resistant Gram-negative bacteria (CR-GNB). This study aimed to assess these issues retrospectively using multicenter data.

METHODS

This multicenter study included CR-GNB infected patients treated with CAZ/AVI-based regimens for more than three days. Patient characteristics, bacterial culture reports, drug-sensitivity test results, and antibiotic use, including CAZ/AVI use, were extracted from the patient's clinical records. The clinical and microbiological efficacy of the combined drug regimen and patient mortality were evaluated according to corresponding definitions. Univariate and multivariate logistic regressions were performed to explore the efficacy and mortality-related factors.

RESULTS

A total of 183 patients with CR-GNB infection were considered for the analysis according to the inclusion and exclusion criteria. After the treatment of CAZ/AVI-based regimens, the clinical efficacy was 75.4 %. The 7-day microbial efficacy and clearance rate after treatment were 43.7 % and 66.0 %, respectively. Moreover, 30-day all-cause and in-hospital mortality were 11.5 % and 14.2 %, respectively. Harboring renal dysfunction (creatinine clearance rate (CCR) of<20 mL/min), cardiovascular diseases, and digestive system diseases were independent risk factors for poor clinical efficacy of CAZ/AVI-based regimens. Bloodstream infection (BSI), patients with the adjusted doses of CAZ/AVI, and CAZ/AVI co-administration with carbapenem were independently associated factors of bacterial clearance by CAZ/AVI-based regimens. Age, total hospital stays, use of mechanical ventilation, and cumulative CAZ/AVI dose were independent factors associated with all-cause mortality.

CONCLUSION

CAZ/AVI was an effective drug in treating CR-GNB infection. CAZ/AVI that is mostly excreted by the kidney and is accumulated in renal impairment should be renally adjusted. Renal dysfunction and the adjusted dose of CAZ/AVI were associated with efficacy. Clinicians should individualize CAZ/AVI regimen and dose by the level of renal function to achieve optimal efficacy and survival. The efficacy of CAZ/AVI in the treatment of CR-GNB infection, as well as the implementation of individualized precision drug administration of CAZ/AVI according to patients' different infection sites, renal function, bacterial types, bacterial resistance mechanisms, blood concentration monitoring and other conditions need to be further studied in multicenter.

What to Do with the New Antibiotics?

Multidrug-resistant Gram-negative bacteria-related infections have become a real public health problem and have exposed the risk of a therapeutic impasse. In recent years, many new antibiotics have been introduced to enrich the therapeutic armamentarium. Among these new molecules, some are mainly of interest for the treatment of the multidrug-resistant infections associated with Pseudomonas aeruginosa (ceftolozane/tazobactam and imipenem/relebactam); others are for carbapenem-resistant infections associated with Enterobacterales (ceftazidime/avibactam, meropenem/vaborbactam); and finally, there are others that are effective on the majority of multidrug-resistant Gram-negative bacilli (cefiderocol). Most international guidelines recommend these new antibiotics in the treatment of microbiologically documented infections. However, given the significant morbidity and mortality of these infections, particularly in the case of inadequate therapy, it is important to consider the place of these antibiotics in probabilistic treatment. Knowledge of the risk factors for multidrug-resistant Gram-negative bacilli (local ecology, prior colonization, failure of prior antibiotic therapy, and source of infection) seems necessary in order to optimize antibiotic prescriptions. In this review, we will assess these different antibiotics according to the epidemiological data.

Pharmacokinetic and pharmacodynamic properties of polymyxin B in Escherichia coli and Klebsiella pneumoniae murine infection models

BACKGROUND

Although polymyxin B has been in use since the late 1950s, there have been limited studies done to unravel its pharmacokinetics (PK) and pharmacodynamics (PD) index.

METHODS

We determined, in neutropenic infected mice, the PK, plasma protein binding and PK/PD index best correlating with efficacy for Escherichia coli and Klebsiella pneumoniae strains.

RESULTS

The pharmacokinetic profile showed non-linear PK; dose was significantly correlated with absorption rate and clearance. The inhibitory sigmoid dose-effect model for the fCmax/MIC index of E. coli fitted best, but was only modestly higher than the R2 of %fT>MIC and fAUC/MIC (R2 0.91-0.93). For K. pneumoniae the fAUC/MIC index had the best fit, which was slightly higher than the R2 of %fT>MIC and fCmax/MIC (R2 0.85-0.91). Static targets of polymyxin B fAUC/MIC were 27.5-102.6 (median 63.5) and 5.9-60.5 (median 11.6) in E. coli and in K. pneumoniae isolates, respectively. A 1 log kill effect was only reached in two E. coli isolates and one K. pneumoniae. The PTA with the standard dosing was low for isolates with MIC >0.25 mg/L.

CONCLUSIONS

This study confirms that fAUC/MIC can describe the exposure-response relationship for polymyxin B. The 1 log kill effect was achieved in the minority of the isolates whereas polymyxin B PK/PD targets cannot be attained for the majority of clinical isolates with the standard dosing regimen, indicating that polymyxin B may be not effective against serious infections as monotherapy.

Efficacy and safety of ceftazidime-avibactam compared to other antimicrobials for the treatment of infections caused by carbapenem-resistant Klebsiella pneumoniae strains, a systematic review and meta-analysis

INTRODUCTION

Carbapenem-resistant Klebsiella pneumoniae (CRKP) infections are a significant public health issue. CRKP infections can increase the mortality of severely ill hospitalised patients and elevate the financial burden of their hospitalisation globally. Colistin and tigecycline are the main antimicrobials which have been widely used for the treatment of CRKP infections. However, novel antimicrobials have been recently launched. Ceftazidime-avibactam (CAZ-AVI) seems one of the most efficient ones.

AIM

The aim of the current systematic literature review and meta-analysis is to assess the efficacy and safety of CAZ-AVI compared to other antimicrobials in adult patients (aged >18) with CRKP infection.

METHODS

All data were retrieved using PubMed/Medline, the Web of Science and Cochrane library. The main outcome was the effective treatment of CRKP infection or the microbiological eradication of CRKP in the culture of biological samples. Secondary outcomes included the impact on 28- or 30-day mortality and adverse effects, if available. Pooled analysis was conducted using Review Manager v. 5.4.1 software (RevMan). The level of statistical significance was set at p < 0.05.

RESULTS

CAZ-AVI was proved more effective than other antimicrobials against CRKP infections and CRKP bloodstream infections (p < 0.00001 and p < 0.0001, respectively). Patients in the CAZ-AVI arm displayed statistically lower 28- and 30-day mortality rates (p = 0.002 and p < 0.00001, respectively). Concerning the microbiological eradication, no meta-analysis was feasible due to high heterogeneity.

CONCLUSION

The promotion of CAZ-AVI for treating CRKP infections over other antimicrobials seems favourable. However, there is a long way ahead to reveal additional scientific findings to further strengthen this statement.

Assessing Clinical Potential of Old Antibiotics against Severe Infections by Multi-Drug-Resistant Gram-Negative Bacteria Using In Silico Modelling

In the light of increasing antimicrobial resistance among gram-negative bacteria and the lack of new more potent antimicrobial agents, new strategies have been explored. Old antibiotics, such as colistin, temocillin, fosfomycin, mecillinam, nitrofurantoin, minocycline, and chloramphenicol, have attracted the attention since they often exhibit in vitro activity against multi-drug-resistant (MDR) gram-negative bacteria, such as Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii. The current review provides a summary of the in vitro activity, pharmacokinetics and PK/PD characteristics of old antibiotics. In silico modelling was then performed using Monte Carlo simulation in order to combine all preclinical data with human pharmacokinetics and determine the probability of target (1-log kill in thigh/lung infection animal models) attainment (PTA) of different dosing regimens. The potential of clinical efficacy of a drug against severe infections by MDR gram-negative bacteria was considered when PTA was >95% at the epidemiological cutoff values of corresponding species. In vitro potent activity against MDR gram-negative pathogens has been shown for colistin, polymyxin B, temocillin (against E. coli and K. pneumoniae), fosfomycin (against E. coli), mecillinam (against E. coli), minocycline (against E. coli, K. pneumoniae, A. baumannii), and chloramphenicol (against E. coli) with ECOFF or MIC90 ≤ 16 mg/L. When preclinical PK/PD targets were combined with human pharmacokinetics, Monte Carlo analysis showed that among the old antibiotics analyzed, there is clinical potential for polymyxin B against E. coli, K. pneumoniae, and A. baumannii; for temocillin against K. pneumoniae and E. coli; for fosfomycin against E. coli and K. pneumoniae; and for mecillinam against E. coli. Clinical studies are needed to verify the potential of those antibiotics to effectively treat infections by multi-drug resistant gram-negative bacteria.

Mortality-Related Risk Factors and Novel Antimicrobial Regimens for Carbapenem-Resistant Enterobacteriaceae Infections: A Systematic Review

OBJECTIVE

Carbapenem-resistant Enterobacteriaceae (CRE) has become a significant public health problem in the last decade. We aimed to explore the risk factors of mortality in patients with CRE infections and to focus on the current evidence on antimicrobial regimens for CRE infections, particularly from the perspective of mortality.

METHODS

A systematic literature review was performed by searching the databases of EMBASE, PubMed, and the Cochrane Library to identify studies that evaluated mortality-related risk factors and antimicrobial regimens for CRE infections published from 2012 to 2022.

RESULTS

In total, 33 and 28 studies were included to analyze risk factors and antibiotic treatment, respectively. The risk factors most frequently reported as significantly associated with CRE mortality were antibiotic use (92.9%; 26/28 studies), comorbidities (88.7%; 23/26 studies), and hospital-related factors (82.8%; 24/29 studies). In 10 studies that did not contain ceftazidime/avibactam (CAZ-AVI) therapy, seven demonstrated significantly lower mortality in combination therapy than in monotherapy. However, 5 of 6 studies identified no substantial difference between CAZ-AVI monotherapy and CAZ-AVI combination therapy. Six studies reported substantially lower mortality in CAZ-AVI regimens than in other regimens.

CONCLUSION

Several risk factors, particularly antibiotic use and patients' comorbidities, are strong risk factors for CRE mortality. The optimal regimen for CRE infections remains controversial. Combination therapy should be considered when carbapenems, colistin, tigecycline, or aminoglycosides are administered. CAZ-AVI appears to be a promising antibiotic for CRE infections. Most importantly, treatment should be individualized according to the source and severity of the disease or other highly related risk factors.

Ceftazidime/Avibactam-Based Versus Polymyxin B-Based Therapeutic Regimens for the Treatment of Carbapenem-Resistant Klebsiella pneumoniae Infection in Critically Ill Patients: A Retrospective Cohort Study

INTRODUCTION

Considering the importance of ceftazidime/avibactam (CAZ/AVI) and polymyxin B (PMB) in treating carbapenem-resistant Klebsiella pneumoniae (CRKP) infection, it is essential to evaluate the efficacy and safety of these agents and provide appropriate medical advice to clinical specialists.

METHODS

We conducted a retrospective cohort study in two Chinese tertiary hospitals for critically ill patients with CRKP infection who received at least 24-h CAZ/AVI-based or PMB-based treatment. A binary logistic model and a Cox proportional hazards regression model were constructed to analyze variables that could potentially affect 30-day microbiological eradication and all-cause mortality, respectively.

RESULTS

From January 2019 to December 2021, 164 eligible patients were divided into CAZ/AVI and PMB cohorts. A notably lower 30-day mortality rate (35.4% vs 69.5%, P < 0.001) and a higher 30-day microbiological eradication rate (80.5% vs 32.9%, P < 0.001) were observed for patients receiving CAZ/AVI-based treatment, compared with cases in the PMB group. A longer antimicrobial treatment duration (> 7 days) could also significantly decrease the mortality rate and increase the microbiological eradication rate. Female patients had a higher survival rate than male patients. Age over 65 years, sepsis, continuous renal replacement therapy, and organ transplantation were identified as negative factors for survival. In the subgroup analysis, CAZ/AVI combined with tigecycline or amikacin could effectively lower mortality. According to safety evaluation results, potential elevation of hepatic enzymes was associated with CAZ/AVI-based treatment, while renal impairment was probably related to PMB-based treatment.

CONCLUSIONS

CAZ/AVI was more effective than PMB in treating CRKP-infected patients. Tigecycline and amikacin were proven to be beneficial as concomitant agents in combination with CAZ/AVI. A treatment period lasting over 7 days was recommended. Hepatoxicity of CAZ/AVI and nephrotoxicity of PMB should be monitored carefully. Further well-designed studies should be performed to verify our conclusion.

Risk Factors for Mortality and Outcomes in Hematological Malignancy Patients with Carbapenem-Resistant Klebsiella pneumoniae Bloodstream Infections

Background

This study aimed to identify risk factors for mortality and outcomes in hematological malignancy (HM) patients with bloodstream infection (BSI) caused by carbapenem-resistant Klebsiella pneumoniae (CRKP).

Methods

A retrospective study was conducted at a tertiary teaching hospital in Henan Province, China, between January 2018 and December 2021. All BSIs caused by CRKP in hospitalized HM patients were identified. Data on patient demographics, disease, laboratory tests, treatment regimens, outcomes of infection, and the antimicrobial susceptibility of each isolate were collected from medical records.

Results

A total of 129 patients with CRKP BSI were included in the study, and the 28-day mortality rate was 80.6% (104/129). In Cox analysis an absolute neutrophil count < 500 at discharge (hazard ratio [HR] 6.386, 95% confidence interval [CI] 3.074–13.266, p < 0.001), intensive care unit admission (HR 1.834, 95% CI 1.065–3.157, p = 0.029), and higher Pitt bacteremia score (HR 1.185, 95% CI 1.118–1.255, p < 0.001) were independent risk factors associated with 28-day mortality. Survival curve analysis indicated that compared with ceftazidime-avibactam-based therapy, both polymyxin b (HR 8.175, 95% CI 1.099–60.804, p = 0.040) and tigecycline (HR 14.527, 95% CI 2.000–105.541, p =0.008) were associated with a higher risk of mortality.

Conclusion

In HM patients CRKP BSI resulted in high mortality. Intensive care unit admission, higher Pitt bacteremia score, and absolute neutrophil count < 500 at discharge were independently associated with higher mortality. Early initiation of new agents such as ceftazidime-avibactam may improve outcomes.

Update of clinical application in ceftazidime-avibactam for multidrug-resistant Gram-negative bacteria infections

PURPOSE

Multidrug-resistant Gram-negative bacteria (MDR-GNB) have become a major global public health threat. Ceftazidime-avibactam (CAZ-AVI) is a newer combination of β-lactam/β-lactamase inhibitor, with activity against carbapenem-resistant Enterobacterales (CRE) and carbapenem-resistant Pseudomonas aeruginosa (CRPA). The aim of this review is to describe the recent real-world experience of CAZ-AVI for the infections due to MDR-GNB.

METHODS

We searched PubMed, Embase and Google Scholar for clinical application in CAZ-AVI for MDR-GNB infections. Reference lists were reviewed and synthesized for narrative review.

RESULTS

MDRGNB infections are associated with higher mortality significantly comparing to drug-susceptible bacterial infections. Fortunately, CAZ-AVI shows significant benefits for infections due to KPC or OXA-48 CRE, comparing to colistin, carbapenem, aminoglycoside and other older agents, even in those with immunocompromised status. The efficacy of CAZ-AVI varies in different infection sites due to CRE, which is lower in pneumonia. Early use is associated with improved clinical outcomes. Noteworthy, when adopted as salvage therapy, CAZ-AVI is still superior to other GNB active antibiotics. CAZ-AVI plus aztreonam is recommended as the first line of MBL-CRE infections. However, for infections caused by KPC- and OXA-48-producing isolates, further investigations are needed to demonstrate the benefit of combination therapy. Besides CRE, CAZ-AVI is also active to MDR-PA. However, the development of resistance in CRE and MDR-PA against CAZ-AVI is alarming, and more investigations and studies are needed to prevent, diagnose, and treat infections due to CAZ-AVI-resistant pathogens.

CONCLUSIONS

CAZ-AVI appears to be a valuable therapeutic option in MDR-GNB infections. Using CAZ-AVI appropriately to improve efficacy and decrease the emergence of resistance is important.