Ceftazidime-Avibactam in Combination with In Vitro Non-susceptible Antimicrobials Versus Ceftazidime-Avibactam in Monotherapy in Critically Ill Patients with Carbapenem-Resistant Klebsiella Pneumoniae Infection: A Retrospective Cohort Study

Efficacy and Safety of Ceftazidime-Avibactam Alone versus Ceftazidime-Avibactam Plus Fosfomycin for the Treatment of Hospital-Acquired Pneumonia and Ventilator-Associated Pneumonia: A Multicentric Retrospective Study from the SUSANA Cohort

Hospital-acquired pneumonia (HAP) and ventilation-associated pneumonia (VAP) are challenging clinical conditions due to the challenging tissue penetrability of the lung. This study aims to evaluate the potential role of fosfomycin (FOS) associated with ceftazidime/avibactam (CZA) in improving the outcome in this setting. We performed a retrospective study including people with HAP or VAP treated with CZA or CZA+FOS for at least 72 h. Clinical data were collected from the SUSANA study, a multicentric cohort to monitor the efficacy and safety of the newer antimicrobial agents. A total of 75 nosocomial pneumonia episodes were included in the analysis. Of these, 34 received CZA alone and 41 in combination with FOS (CZA+FOS). People treated with CZA alone were older, more frequently male, received a prolonged infusion more frequently, and were less frequently affected by carbapenem-resistant infections (p = 0.01, p = 0.06, p < 0.001, p = 0.03, respectively). No difference was found in terms of survival at 28 days from treatment start between CZA and CZA+FOS at the multivariate analysis (HR = 0.32; 95% CI = 0.07-1.39; p = 0.128), while prolonged infusion showed a lower mortality rate at 28 days (HR = 0.34; 95% CI = 0.14-0.96; p = 0.04). Regarding safety, three adverse events (one acute kidney failure, one multiorgan failure, and one urticaria) were reported. Our study found no significant association between combination therapy and mortality. Further investigations, with larger and more homogeneous samples, are needed to evaluate the role of combination therapy in this setting.

Effect of ceftazidime-avibactam combined with different antimicrobials against carbapenem-resistant Klebsiella pneumoniae

This study aimed to assess the in vitro efficacy of ceftazidime-avibactam (CZA) in combination with various antimicrobial agents against carbapenem-resistant Klebsiella pneumoniae (CRKP). We selected 59 clinical CRKP isolates containing distinct drug resistance mechanisms. The minimum inhibitory concentrations (MICs) of meropenem (MEM), colistin (COL), eravacycline (ERA), amikacin (AK), fosfomycin (FOS), and aztreonam (ATM), both individually and in combination with CZA, were tested using the checkerboard method. The interactions of antimicrobial agent combinations were assessed by fractional inhibitory concentration index (FICI) and susceptible breakpoint index (SBPI). The time-kill curve assay was employed to dynamically evaluate the effects of these drugs alone and in combination format. In the checkerboard assay, the combination of CZA+MEM showed the highest level of synergistic effect against both KPC-producing and carbapenemase-non-producing isolates, with synergy rates of 91.3% and 100%, respectively. Following closely was the combination of FOS+CZA . For metallo-beta-lactamases (MBLs) producing strains, ATM+CZA displayed complete synergy, while the combination of MEM+CZA showed a synergy rate of only 57.14% for NDM-producing strains and 91.67% for IMP-producing strains. In the time-kill assay, MEM+CZA also demonstrated significant synergistic effects against the two KPC-2-producing isolates (Y070 and L70), the two carbapenemase-non-producing isolates (Y083 and L093), and the NDM-1-producing strain L13, with reductions in log10 CFU/mL exceeding 10 compared to the control. Against the IMP-producing strain Y047, ATM+CZA exhibited the highest synergistic effect, resulting in a log10 CFU/mL reduction of 10.43 compared to the control. The combination of CZA and MEM exhibited good synergistic effects against KPC-producing and non-enzyme-producing strains, followed by the FOS+CZA combination. Among MBL-producing strains, ATM+CZA demonstrated the most pronounced synergistic effect. However, the combinations of CZA with ERA, AK, and COL show irrelevant effects against the tested clinical isolates.

IMPORTANCE

Our study confirmed the efficacy of the combination CZA+MEM against KPC-producing and non-carbapenemase-producing strains. For metalloenzyme-producing strains, CZA+ATM demonstrated the most significant synergy. Additionally, CZA exhibited a notable synergy effect when combined with FOS. These combination therapies present promising new options for the treatment of CRKP infection.

Novel Siderophore Cephalosporin and Combinations of Cephalosporins with β-Lactamase Inhibitors as an Advancement in Treatment of Ventilator-Associated Pneumonia

In an era of increasing antibiotic resistance among pathogens, the treatment options for infectious diseases are diminishing. One of the clinical groups especially vulnerable to this threat are patients who are hospitalized in intensive care units due to ventilator-associated pneumonia caused by multidrug-resistant/extensively drug-resistant Gram-negative bacteria. In order to prevent the exhaustion of therapeutic options for this life-threatening condition, there is an urgent need for new pharmaceuticals. Novel β-lactam antibiotics, including combinations of cephalosporins with β-lactamase inhibitors, are proposed as a solution to this escalating problem. The unique mechanism of action, distinctive to this new group of siderophore cephalosporins, can overcome multidrug resistance, which is raising high expectations. In this review, we present the summarized results of clinical trials, in vitro studies, and case studies on the therapeutic efficacy of cefoperazone-sulbactam, ceftolozane-tazobactam, ceftazidime-avibactam, and cefiderocol in the treatment of ventilator-associated pneumonia. We demonstrate that treatment strategies based on siderophore cephalosporins and combinations of β-lactams with β-lactamases inhibitors show comparable or higher clinical efficacy than those used with classic pharmaceuticals, like carbapenems, colistin, or tigecycline, and are often associated with a lower risk of adverse events.

Ceftazidime-avibactam combination therapy versus monotherapy for treating carbapenem-resistant gram-negative infection: a systemic review and meta-analysis

BACKGROUND

This meta-analysis was conducted to compare the efficacy of ceftazidime-avibactam combination therapy with that of monotherapy in the treatment of carbapenem-resistant Gram-negative bacterial (CR-GNB).

METHODS

A literature search of PubMed, Embase, the Cochrane Library, and ClinicalTrials.gov was conducted until September 1, 2023. Only studies that compared CZA combination therapy with monotherapy for CR-GNB infections were included.

RESULTS

A total of 25 studies (23 retrospective observational studies and 2 prospective studies) involving 2676 patients were included. There was no significant difference in 30-day mortality between the study group receiving combination therapy and the control group receiving monotherapy (risk ratio [RR] 0.91; 95% confidence interval [CI] 0.71-1.18). In addition, no significant differences were observed between the study and the control group in terms of in-hospital mortality (RR 1.00; 95% CI 0.79-1.27), 14-day mortality (RR 1.54; 95% CI 0.24-9.91), 90-day mortality (RR 1.18; 95% CI 0.62-2.22), and clinical cure rate (RR 0.95; 95% CI 0.84-1.08). However, the combination group had a borderline higher microbiological eradication rate than the control group (RR 1.15; 95% CI 1.00-1.32).

CONCLUSIONS

Compared to monotherapy, CZA combination therapy did not yield additional clinical benefits. However, combination therapy may be associated with favorable microbiological outcomes.

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 Combination Therapy versus Monotherapy for the Treatment Carbapenem-Resistant Gram-Negative Bacterial Infections: A Retrospective Observational Study

Purpose

Since the introduction of ceftazidime-avibactam (CZA) in the Chinese market, accumulating clinical evidence has substantiated its efficacy in the treatment of infections caused by carbapenem-resistant gram-negative bacteria (CR-GNB). Nevertheless, an ongoing debate persists concerning the choice between monotherapy and combination therapy when devising clinical anti-infection protocols.

Patients and Methods

This retrospective, single-center observational study enrolled patients with CR-GNB infections who received CZA treatment between December 2019 and August 2023. The primary outcome assessed was 30-day mortality, and the secondary outcome measured was 14-day bacterial clearance. A multivariate Cox regression model was used to identify variables that were independently associated with 30-day mortality rate.

Results

Eighty-three patients were enrolled in the study; of which, 45 received CZA monotherapy, whereas 38 received combination therapy. The overall 30-day mortality rate was 31.3%, and no significant difference was observed in the 30-day mortality rates between the CZA combination therapy and monotherapy groups (31.6% vs 31.1%, p=0.963). After adjustment by propensity score matching, the 30-day mortality rate was not significantly different between the two groups (28.6% vs 31.4%, p=0.794). Multivariate COX analysis revealed that age and SOFA score were independent predictors of 30-day mortality.

Conclusion

Combination therapy with CZA and other antimicrobials was not found to have an advantage over monotherapy in reducing the 30-day mortality rate.

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.

Mutations in ompK36 differentially impact in vitro synergy of meropenem/vaborbactam and ceftazidime/avibactam in combination with other antibiotics against KPC-producing Klebsiella pneumoniae

Objectives

Ceftazidime/avibactam and meropenem/vaborbactam are preferred agents for Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae (KPC-Kp) infections and are often used in combination with other agents. We aimed to characterize the synergy of combinations against KPC-Kp with varying ompK36 genotypes.

Methods

KPC-Kp that harboured ompK36 WT, IS5 or glycine-aspartic acid duplication (GD) genotypes were selected. MICs were determined in triplicate. Synergy was assessed by time-kill assays for ceftazidime/avibactam and meropenem/vaborbactam in combination with colistin, gentamicin, tigecycline, meropenem or fosfomycin against 1 × 108 cfu/mL KPC-Kp.

Results

KPC-Kp harboured ompK36 WT (n = 5), IS5 (n = 5) or GD (n = 5); 11 were KPC-2 and 4 were KPC-3. All were susceptible to ceftazidime/avibactam and meropenem/vaborbactam. In time-kill analysis, ceftazidime/avibactam and meropenem/vaborbactam 1 × MIC exhibited mean 24 h log-kills of -2.01 and -0.84, respectively. Ceftazidime/avibactam was synergistic in combination with colistin independent of ompK36 genotype. Ceftazidime/avibactam combinations impacted by porin mutations (compared to WT) were meropenem (-5.18 versus -6.62 mean log-kill, P < 0.001) and fosfomycin (-3.98 versus -6.58, P = 0.058). Mean log-kills with meropenem/vaborbactam were greatest in combination with gentamicin (-5.36). In the presence of porin mutations, meropenem/vaborbactam killing activity was potentiated by the addition of colistin (-6.65 versus -0.70, P = 0.03) and fosfomycin (-3.12 versus 1.54, P = 0.003).

Conclusions

Our results shed new light on the synergy of ceftazidime/avibactam and meropenem/vaborbactam combinations against KPC-Kp with or without porin mutations. Killing activity of ceftazidime/avibactam with other cell wall active agents was decreased against isolates with porin mutations. On the other hand, some meropenem/vaborbactam combinations demonstrated enhanced killing in the presence of porin mutations.

OXA-48 Dominance Meets Ceftazidime-Avibactam: A Battle Against Life-Threatening Carbapenem-Resistant Klebsiella pneumoniae Infections in the Intensive Care Unit

Objective In this study, we aimed to describe the outcomes in ICU patients with bloodstream infection (BSI) or ventilatory-associated pneumonia (VAP) due to carbapenem-resistant Klebsiella pneumoniae (CRKP) who received ceftazidime-avibactam treatment at a tertiary care university hospital. Methods Patients aged 18 years or older who were admitted to the Anesthesiology and Reanimation ICU at Bursa Uludag University Faculty of Medicine Hospital between June 13, 2021, and July 16, 2023, and diagnosed with BSI or VAP due to CRKP were included in this study. Results A total of 42 patients treated with ceftazidime-avibactam were included. Total crude mortality rates were 33.3% on day 14 and 54.8% on day 30. Mortality rates on the 14th and 30th days were 37.5% and 62.5% in patients with BSI and 27.8% and 44.4% in patients with VAP, respectively. There was no statistically significant difference between monotherapy and combination therapy in terms of mortality rates on days 14 and 30, respectively (3/11 vs. 11/31, p=0.620; 5/11 vs. 18/31, p=0.470). Immunosuppression (10/11 vs. 13/31, p=0.005), the Sequential Organ Failure Assessment (SOFA) score ≥8 (at the initiation of treatment; 19/25 vs. 4/17, p<0.001), INCREMENT-CPE score ≥10 (12/16 vs. 3/10, p=0.024) and longer duration (in days) from culture collection to treatment initiation (5.0 ± 0.61 vs. 3.11 ± 0.48, p=0.024) were found to have a statistically significant effect on 30-day mortality. In multivariate analysis, a SOFA score ≥8 at the initiation of treatment (p=0.037, OR: 17.442, 95% CI: 1.187-256.280) was found to be a significant risk factor affecting mortality (30-day). Conclusion The mortality rates of patients with CRKP infection who were followed up in the ICU were found to be high, and it was observed that whether ceftazidime-avibactam treatment was given as a combination or monotherapy did not affect mortality. Further multicentre studies with a larger number of patients are needed to gain a comprehensive understanding of the topic, given that this treatment is typically reserved for documented infections.

Ceftazidime-Avibactam for Carbapenem-Resistant Gram-Negative Bacteria Infections: A Real-World Experience in the ICU

Purpose

Ceftazidime-avibactam (C-A) is a treatment option for carbapenem-resistant gram-negative bacterial (CR-GNB) infections, but little is known regarding its suitability for the intensive care unit (ICU). The current study aimed to analyze use of C-A for critically ill patients, determine independent predictors of clinical outcome and mortality and explore routine dosages for patients in continuous renal replacement therapy (CRRT).

Patients and Methods

A single-center, retrospective and observational study was conducted in critically ill patients receiving different C-A-based therapies for CR-GNB infections in a tertiary teaching hospital in Beijing, China. Demographic data, severity of infection, clinical outcomes and mortality were assessed. The primary and secondary outcome of this study was 90-day all-cause mortality and 14-day clinical response, respectively.

Results

A total of 43 patients with CR-GNB infection were enrolled, including 14 (32.6%) patients received C-A monotherapy. C-A monotherapy and combination with other agents did not affect 14-day clinical response or 90-day survival. All-cause mortality at 90-days was 39.5% (17/43). Multivariate Cox analysis showed that concomitant with bloodstream infection was independent risk factors for 90-day mortality and that the time to initiation of C-A and Acute Physiology and Chronic Health Evaluation (APACHE) score was independent predictors of 14-day clinical response. Five CRRT patients who received high-dose C-A therapy (>3.75 g/d) had prolonged survival compared with 5 who received low-dose C-A (<3.75 g/d, p = 0.03).

Conclusion

C-A was an effective therapy for severe CR-GNB infections and clinical response correlated with the time of C-A initiation. A dosage >3.75g/d C-A was associated with prolonged survival of CRRT patients. Randomized controlled trials or multicenter studies are needed to confirm these findings.

Use of Ceftazidime-Avibactam for Suspected or Confirmed Carbapenem-Resistant Organisms in Children: A Retrospective Study

Background

The incidence of carbapenem-resistant organism (CRO) infections is increasing in children. However, pediatric-specific treatment strategies present unique challenges. Ceftazidime/avibactam is a β-lactam/β-lactamase inhibitor combination, showing adequate efficiency against CRO isolates. However, clinical data on the efficacy of ceftazidime/avibactam in children are still lacking.

Methods

This was a retrospective study of children (aged <18 years) infected with confirmed or suspected carbapenem-resistant pathogens and treated with ceftazidime-avibactam at the First Affiliated Hospital of Zhengzhou University between 2020 and 2022.

Results

We identified 38 children aged 14 (5.0-16.3) years; 20 (52.6%) had hematologic malignancies. 25 children with confirmed CRO infections were administered ceftazidime-avibactam as targeted therapy. The median treatment was 10 (6.0-16.5) days. Among them, 24 had infections caused by carbapenem-resistant Enterobacterales (CRE) (18 carbapenem-resistant Klebsiella pneumoniae and six carbapenem-resistant Escherichia coli species) and one with carbapenem-resistant Pseudomonas aeruginosa strains. The source of infection was the bloodstream in 60.0% of the cases (15/25). The clinical response rate was 84.0% (21/25), and 30-day mortality rate was 20% (5/25). 13 children were administered ceftazidime-avibactam as empiric therapy for suspected infections. The median treatment was 8 (6.0-13.0) days. No deaths occurred and clinical response was achieved in 12 of the 13 patients (92.3%) who empirically treated with ceftazidime-avibactam.

Conclusion

Ceftazidime-avibactam is important for improving survival, and clinical response in children with infections caused by CRO.

In vitro, in vivo and clinical studies comparing the efficacy of ceftazidime-avibactam monotherapy with ceftazidime-avibactam-containing combination regimens against carbapenem-resistant Enterobacterales and multidrug-resistant Pseudomonas aeruginosa isolates or infections: a scoping review

Introduction

Carbapenem-resistant Enterobacterales (CRE) and multidrug-resistant Pseudomonas aeruginosa (MDR-PA) infections are associated with a high risk of morbidity, mortality, and treatment costs. We aimed to evaluate in vitro, in vivo and clinical studies comparing the efficacy of ceftazidime-avibactam (CZA) combination regimens with CZA alone against CRE and/or MDR-PA isolates or infections.

Methods

We systematically reviewed the relevant literature in CINAHL/MEDLINE, Pubmed, Cochrane, Web of Science, Embase, and Scopus until December 1, 2022. Review articles, grey literature, abstracts, comments, editorials, non-peer reviewed articles, non-English articles, and in vitro synergy studies conducted on single isolates were excluded.

Results

22 in vitro, 7 in vivo and 20 clinical studies were evaluated. In vitro studies showed reliable synergy between CZA and aztreonam against metallo-β-lactamase (MBL)-producing isolates. Some studies indicated good in vitro synergy between CZA and amikacin, meropenem, fosfomycin and polymyxins against CRE isolates. For MDR-PA isolates, there are comparatively fewer in vitro or in vivo studies. In observational clinical studies, mortality, clinical cure, adverse events, and development of CZA resistance after exposure were generally similar in monotherapy and combination therapy groups. However, antibiotic-related nephrotoxicity and infection relapses were higher in patients receiving CZA combination therapies.

Discussion

The benefit, if any, of CZA combination regimens in MDR-PA infections is elusive, as very few clinical studies have included these infections. There is no currently documented clinical benefit for the use of CZA combination regimens rather than CZA monotherapy. CZA combined with aztreonam for serious infections due to MBL producers should be evaluated by randomized controlled trials.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=278552, CRD42021278552.

Combination Therapy of Ceftazidime/Avibactam for the Treatment of Patients Infected with Carbapenem-Resistant Klebsiella pneumoniae: A Multicenter Retrospective Study

INTRODUCTION

This study aimed to evaluate the different efficacies between monotherapy and combination therapy with ceftazidime/avibactam (CAZ/AVI) in treating carbapenem-resistant Klebsiella pneumoniae (CRKP) infection.

METHODS

We retrospectively analyzed observational multicenter data from 38 hospitals in China. Multivariate regression analysis was used to explore the association between combination therapy with CAZ/AVI and in-hospital mortality. Propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) were performed to validate our findings.

RESULTS

A total of 132 eligible patients were divided into CAZ/AVI combination therapy (n = 43) and monotherapy (n = 89) cohorts. Multivariate logistic regression showed that there was no statistically significant relationship between combination therapy and a lower risk of in-hospital mortality [odds ratio (OR) 0.907, 95% confidence interval (CI) 0.329-2.498, p = 0.850]. In the subgroup of critical patients who were in the intensive care unit (ICU) (OR 0.943, 95% CI 0.221-4.033, p = 0.937) or with sequential organ failure assessment (SOFA) ≥ 3 (OR 0.733, 95% CI 0.191-2.808, p = 0.650), CAZ/AVI combination therapy was not a lower risk factor for in-hospital mortality. Moreover, in the subgroup of patients using CAZ/AVI plus tigecycline (accounting for 46.5% in the combination therapy) compared with CAZ/AVI monotherapy, there was no statistical difference between the two groups in in-hospital mortality, nor in the subgroup of patients with CRKP-associated pneumonia.

CONCLUSION

Combination therapy (or CAZ/AVI combined with tigecycline) and monotherapy with CAZ/AVI had similar prognoses in patients with only CRKP infection (or CRKP-associated pneumonia), as well as in critically ill patients. Larger randomized controlled trials are warranted to confirm these findings.

The place of new antibiotics for Gram-negative bacterial infections in intensive care: report of a consensus conference

INTRODUCTION

New beta-lactams, associated or not with beta-lactamase inhibitors (NBs/BIs), can respond to the spread of carbapenemase-producing enterobacteriales and nonfermenting carbapenem-resistant bacteria. The risk of emergence of resistance to these NBs/BIs makes guidelines necessary. The SRLF organized a consensus conference in December 2022.

METHODS

An ad hoc committee without any conflict of interest (CoI) with the subject identified the molecules (ceftolozane-tazobactam, ceftazidime-avibactam, imipenem-cilastatin-relebactam, meropenem-vaborbactam and cefiderocol); defined 6 generic questions; drew up a list of subquestions according to the population, intervention, comparison and outcomes (PICO) model; and reviewed the literature using predefined keywords. The quality of the data was assessed using the GRADE methodology. Seven experts in the field proposed their own answers to the questions in a public session and answered questions from the jury (a panel of 10 critical-care physicians without any CoI) and the public. The jury then met alone for 48 h to write its recommendations. Due to the frequent lack of powerful studies that have used clinically important criteria of judgment, the recommendations were formulated as expert opinions as often as necessary.

RESULTS

The jury provided 17 statements answering 6 questions: (1) Is there a place in the ICU for the probabilistic use of new NBs/IBs active against Gram-negative bacteria? (2) In the context of documented infections with sensitivity to several of these molecules, are there pharmacokinetic, pharmacodynamic, ecological or medico-economic elements for prioritization? (3) What are the possible combinations with these molecules and in what context? (4) Should we integrate these new molecules into a carbapenem-sparing strategy? (5) What pharmacokinetic and pharmacodynamic data are available to optimize their mode of administration in critically ill patients? (6) What are the dosage adaptations in cases of renal insufficiency, hepatocellular insufficiency or obesity?

CONCLUSION

These recommendations should optimize the use of NBs/BIs in ICU patients.

Novel evidence on sepsis-inducing pathogens: from laboratory to bedside

Sepsis is a life-threatening condition and a significant cause of preventable morbidity and mortality globally. Among the leading causative agents of sepsis are bacterial pathogens Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, and Streptococcus pyogenes, along with fungal pathogens of the Candida species. Here, we focus on evidence from human studies but also include in vitro and in vivo cellular and molecular evidence, exploring how bacterial and fungal pathogens are associated with bloodstream infection and sepsis. This review presents a narrative update on pathogen epidemiology, virulence factors, host factors of susceptibility, mechanisms of immunomodulation, current therapies, antibiotic resistance, and opportunities for diagnosis, prognosis, and therapeutics, through the perspective of bloodstream infection and sepsis. A list of curated novel host and pathogen factors, diagnostic and prognostic markers, and potential therapeutical targets to tackle sepsis from the research laboratory is presented. Further, we discuss the complex nature of sepsis depending on the sepsis-inducing pathogen and host susceptibility, the more common strains associated with severe pathology and how these aspects may impact in the management of the clinical presentation of sepsis.

The Use of Intravenous Fosfomycin in Clinical Practice: A 5-Year Retrospective Study in a Tertiary Hospital in Italy

Fosfomycin in intravenous (IV) formulation has re-emerged as a valuable tool in the treatment of multi-drug resistant (MDR) and extensively drug-resistant (XDR) infections because of its broad spectrum of antibacterial action and pharmacokinetic characteristics. This retrospective study aimed to evaluate how fosfomycin was used in patients admitted to the Polyclinic of Palermo between January 2017 and July 2022. Clinical indications, therapeutic associations, clinical outcomes, and any side effects were analyzed. Intravenous fosfomycin was used in 343 patients, 63% male, with a mean age of 68 years (range 15-95). Urinary tract infections (UTIs) and hospital-acquired pneumonia (HAP) were the main indications for treatment (19% and 18% of the total cases, respectively), followed by skin and soft tissue infections and sepsis. IV fosfomycin was administered in combination with other antibacterial agents, the most common of which were ceftazidime/avibactam (35%), meropenem (17%), and colistin (14%). Nineteen patients received it as monotherapy for UTIs. About 66% had resolution of the infectious process with clinical remission (cure or discharge). Electrolyte disturbances occurred in 2.6% and gastrointestinal symptoms occurred in 2.9%. The data showed that IV fosfomycin is a safe and effective therapeutic option in the treatment of infections with multidrug-resistant microorganisms.

Efficacy of ceftazidime-avibactam in various combinations for the treatment of experimental osteomyelitis due to Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae

BACKGROUND

Optimal treatment of carbapenemase-producing Enterobacterales (CPE) bone infections is poorly defined. This study evaluated the efficacy of the novel beta-lactam-beta-lactamase inhibitor-ceftazidime-avibactam (CAZ-AVI)-with different antibiotic combinations in an experimental model of CPE osteomyelitis.

METHODS

KPC-99YC is a clinical strain of Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae with intermediate susceptibility to meropenem (MIC 4 mg/L), gentamicin (MIC 0.25 mg/L), colistin (MIC 0.25 mg/L), fosfomycin (MIC 4 mg/L) and ceftazidime-avibactam (MIC 1 mg/L). Time-kill curves were performed at 4x MIC. Osteomyelitis was induced in rabbits by tibial injection of 2×10⁸ CFU of KPC-99YC. Six groups started treatment 14 days later for 7 days: control, colistin, CAZ-AVI, CAZ-AVI plus gentamicin, CAZ-AVI plus colistin and CAZ-AVI plus fosfomycin. Antibiotic dosages were selected to simulate plasma concentrations obtained in humans. Treatment was evaluated according to bone cultures quantified in log₁₀ CFU.

RESULTS

In vitro, CAZ-AVI plus colistin or gentamicin were rapidly bactericidal in contrast with CAZ-AVI plus fosfomycin. In vivo, compared with controls, colistin alone (P = 0.045) and CAZ-AVI alone or in combination significantly lowered bone bacterial counts (P < 0.001). Bone sterilisation was achieved in 67% and 100% of animals with combinations of CAZ-AVI plus colistin or gentamicin (P = 0.001 and P < 0.001, respectively) whereas other treatments were no different from controls. CAZ-AVI plus gentamicin provided greater bone bacterial reduction than CAZ-AVI plus colistin (P = 0.033). No CAZ-AVI-resistant strains emerged in treated rabbits, regardless of combination.

CONCLUSIONS

CAZ-AVI plus gentamicin was the best effective combination therapy. Combinations with CAZ-AVI appear to be a promising treatment of KPC-producing Klebsiella pneumoniae osteomyelitis.

Effect of ceftazidime/avibactam plus fosfomycin combination on 30 day mortality in patients with bloodstream infections caused by KPC-producing Klebsiella pneumoniae: results from a multicentre retrospective study

Introduction

The primary outcome of the study was to evaluate the effect on 30 day mortality of the combination ceftazidime/avibactam + fosfomycin in the treatment of bloodstream infections (BSIs) caused by KPC-producing Klebsiella pneumoniae (KPC-Kp).

Materials and methods

From October 2018 to March 2021, a retrospective, two-centre study was performed on patients with KPC-Kp BSI hospitalized at Sapienza University (Rome) and ISMETT-IRCCS (Palermo) and treated with ceftazidime/avibactam-containing regimens. A matched cohort (1:1) analysis was performed. Cases were patients receiving ceftazidime/avibactam + fosfomycin and controls were patients receiving ceftazidime/avibactam alone or in combination with in vitro non-active drugs different from fosfomycin (ceftazidime/avibactam ± other). Patients were matched for age, Charlson comorbidity index, ward of isolation (ICU or non-ICU), source of infection and severity of BSI, expressed as INCREMENT carbapenemase-producing Enterobacteriaceae (CPE) score.

Results

Overall, 221 patients were included in the study. Following the 1:1 match, 122 subjects were retrieved: 61 cases (ceftazidime/avibactam + fosfomycin) and 61 controls (ceftazidime/avibactam ± other). No difference in overall mortality emerged between cases and controls, whereas controls had more non-BSI KPC-Kp infections and a higher number of deaths attributable to secondary infections. Almost half of ceftazidime/avibactam + fosfomycin patients were prescribed fosfomycin without MIC fosfomycin availability. No difference in the outcome emerged after stratification for fosfomycin susceptibility availability and dosage. SARS-CoV-2 infection and ICS ≥ 8 independently predicted 30 day mortality, whereas an appropriate definitive therapy was protective.

Conclusions

Our data show that fosfomycin was used in the treatment of KPC-Kp BSI independently from having its susceptibility testing available. Although no difference was found in 30 day overall mortality, ceftazidime/avibactam + fosfomycin was associated with a lower rate of subsequent KPC-Kp infections and secondary infections than other ceftazidime/avibactam-based regimens.

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.

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.

Antimicrobial safety considerations in critically ill patients: part II: focused on anti-microbial toxicities

INTRODUCTION

Antibiotic prescription is a challenging issue in critical care settings. Different pharmacokinetic and pharmacodynamic properties, polypharmacy, drug interactions, and high incidence of multidrug-resistant microorganisms in this population can influence the selection, safety, and efficacy of prescribed antibiotics.

AREAS COVERED

In the current article we searched PubMed, Scopus and Google Scholar for neurotoxicities, hematologic toxicity and fluid stewardship in intensive care units.

EXPERT OPINION

Critically ill patients who receive antimicrobial agents should be monitored for neurological, hematologic toxicities especially seizure, thrombocytopenia, and clostridioides infections. Other toxicities including QTc prolongation, electrolyte disturbances, liver enzyme elevation, and infusion-related reactions were being considered. Other changes, including fluid overload, hypoalbuminemia, augmented renal clearance, increased cardiac outputs in septic shock, and acute kidney injury, may influence treatment efficiency and patient outcome.

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

Background: The worldwide outbreak of carbapenem-resistant Klebsiella pneumoniae (CRKP) has become an urgent public health problem. High mortality and lack of effective treatments further pose new challenges to control this infection. However, studies about the evaluation of available antibiotics for CRKP infection are limited. The present study aimed to compare the efficacy of polymyxin B versus ceftazidime-avibactam (CAZ/AVI) in Chinese patients with CRKP infections and to identify risk factors affecting 7-day bacterial eradication and 28-day all-cause mortality. Methods: From January 8, 2018, to July 6, 2020, a total of 115 adult CRKP infected patients from two tertiary teaching hospitals in Shanghai, China were enrolled based on the inclusion and exclusion criteria. By reviewing electronic medical records of these patients, demographic and clinical data were extracted. The selected patients were divided into polymyxin B and CAZ/AVI groups according to primary antibiotic exposure to compare therapeutic effects. Binary logistic and cox's regression analysis were performed to identify risk factors for 7-day bacterial eradication and all-cause mortality. Results: One hundred and five patients were treated with polymyxin B (67.8%) or CAZ/AVI (32.2%). Patients in the CAZ/AVI group had significantly lower rates of 28-day mortality (8.1 vs 29.5%, p = 0.013), higher microbiological eradication and 28-day clinical success. Multivariate analysis showed that Charlson comorbidity index (≥3) and prior antibiotic use within 90 days were independent risk factors for poor microbiological eradication. Cox's regression analysis indicated that the length of hospitalization after CRKP infection and baseline creatinine clearance negatively affected 28-day mortality. Conclusion: CAZ/AVI was more effective than polymyxin B and appeared to be a promising drug for CRKP infection, especially for critically ill patients.

Efficacy of Ceftazidime-Avibactam in the Treatment of Carbapenem-Resistant Klebsiella pneumoniae Infection After Kidney Transplantation

Purpose

The clinical efficacy of ceftazidime-avibactam (CAZ-AVI) in treating carbapenem-resistant Klebsiella pneumoniae (CRKP)-infected recipients after kidney transplantation (KT) has not been well evaluated. We aimed to assess its efficacy in a single-center cohort of KT recipients infected with CRKP.

Materials and Methods

We retrospectively observed KT recipients diagnosed with CRKP infection from June 2019 to July 2021. The primary outcome was 30-day mortality and secondary outcomes were 14-day clinical cure and 14-day microbiological cure. Logistic regression analysis was used to evaluate the relationship between CAZ-AVI treatment and prognosis.

Results

A total of 54 CRKP-infected KT recipients were recorded in this study. Twenty-two recipients received CAZ-AVI and 32 received other antibiotic regimens. Recipients in both groups had similar baseline characteristics, with the most common site of infection being surgical site infections (n=27; 50.0%) and bloodstream infections (n=23; 42.6%). Recipients treated with CAZ-AVI had significantly lower 30-day mortality (3/22 vs 14/32, P=0.019), significantly higher 14-day clinical cure (18/22 vs 17/32, P=0.030) and 14-day microbiological cure (19/22 vs 15/32, P=0.003) compared with recipients receiving other treatment regimens. Kaplan–Meier survival curves for 30-day mortality confirmed the findings (log-rank=0.014). In a multivariate logistic regression model, receiving CAZ-AVI was found to be an independent protective factor for 30-day mortality (odds ratio=0.148, 95% confidence interval, 0.027–0.800; P=0.026). No significant side effects were recorded.

Conclusion

CAZ-AVI may be more valuable than other antibiotic regimens for the treatment of CRKP infection after kidney transplantation, and further large randomized controlled trials are needed to assess its efficacy.

Ceftazidime-Avibactam-Based Versus Tigecycline-Based Regimen for the Treatment of Carbapenem-Resistant Klebsiella pneumoniae-Induced Pneumonia in Critically Ill Patients

INTRODUCTION

The aim of the present study was to assess the safety profile and outcomes of a ceftazidime-avibactam (CAZ-AVI)-based regimen and compare them with those of a tigecycline (TGC)-based regimen in intensive care unit (ICU) for the treatment of carbapenem-resistant Klebsiella pneumoniae (CRKP), which is classified into hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP).

METHODS

Clinical and microbiological cure rates, 28-day survival rates, and safety evaluation findings were compared between patients treated with CAZ-AVI-based regimen and those treated with TGC-based regimen in this retrospective study. Conventional multivariate logistic regression analysis and regression adjustment analysis with propensity score (PS) were performed to control for confounding variables.

RESULTS

A total of 105 cases of critically ill ICU patients with CRKP-induced HAP or VAP were included in the present study from July 2019 to September 2020; 62 patients (59%) received TGC-based regimen and 43 patients (41%) received CAZ-AVI-based regimen. The most common concomitant agent in the CAZ-AVI group and TGC group was carbapenem (44.2% versus 62.9%, P = 0.058), while only a small proportion of the study population received CAZ-AVI and TGC monotherapy (20.9% versus 6.5%, P = 0.027). The clinical and microbiological cure rates of the CAZ-AVI group were superior to those of the TGC group [51.2% versus 29.0% (P = 0.022) and 74.4% versus 33.9% (P < 0.001), respectively]. No significant differences in the 28-day survival rates were identified between the two groups (69.8% versus 66.1%, P = 0.695). Conventional multivariate logistic regression and PS analyses showed that patients who had used CAZ-AVI were more likely to have achieved a clinical cure [4.767 (95%CI 1.694-13.414), P=0.003;3.405 (95%CI 1.304-8.889), P=0.012] and microbiological success [6.664 (95%CI 2.626-16.915), P<0.001;7.778 (95%CI 2.717-22.265), P<0.001] than patients who used TGC. However, the difference in the 28-day survival rates between the two groups was not significant. According to the safety evaluation findings, the CAZ-AVI group exhibited a generally lower incidence of adverse reactions compared with that in the TGC group.

CONCLUSIONS

CAZ-AVI may be a suitable alternative for TGC in the treatment of critically ill patients with CRKP-induced HAP or VAP. These observations require further confirmation in larger randomized prospective clinical trials.