Ceftazidime-avibactam Group Research Articles

Ceftazidime-avibactam versus other antimicrobial agents for treatment of Multidrug-resistant Pseudomonas aeruginosa: a systematic review and meta-analysis.

Multidrug-resistant Pseudomonas aeruginosa (MDR-PA) is a life-threatening infection with limited treatment options. This is the first meta-analysis of recently published data to compare the clinical outcomes of ceftazidime-avibactam (CAZ-AVI) with other antimicrobial agents in treating MDR-PA infections. Systematic review and meta-analysis. PubMed, Embase and the Cochrane Library have been systematically reviewed, for publications in the English language, from database inception to July 2023. Studies comparing CAZ-AVI outcomes with other antimicrobial agents were included. In-hospital mortality & 30-day mortality were assessed as the main outcomes. 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.5.4 was employed for the meta-analysis. The meta-analysis included four retrospective studies, enrolling 1934 patients. The CAZ-AVI group demonstrated significantly lower in-hospital mortality (risk ratio (RR) = 0.60, 95% CI:0.37-0.97, I2 = 74%, p = 0.04) in three studies with 1444 patients and lower 30-day mortality, in 438 patients from three studies (RR = 0.54, 95% CI:0.28-1.05, I2 = 67%, p = 0.07). No significant difference in clinical success, microbiological success, length of hospital, and ICU stay was observed. This meta-analysis demonstrated that CAZ-AVI treatment significantly lowered in-hospital mortality compared with other antimicrobial agents in MDR-PA infections. However, the analysis only included a few observational studies and high-quality, randomized controlled trials are needed to investigate further the scope of CAZ-AVI in MDR-PA infections.

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

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 (≥ 3months) 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. 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. 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. 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. PROSPERO CRD42022362856.

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

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. 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. 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%). 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 efficacy and drug resistance of ceftazidime-avibactam in the treatment of Carbapenem-resistant gram-negative bacilli infection.

To examine the clinical efficacy, safety, and resistance of Ceftazidime-Avibactam (CAZ-AVI) in patients with Carbapenem-resistant Gram-negative bacilli (CR-GNB) infections. We retrospectively analyzed relevant data of CR-GNB infected patients receiving CAZ-AVI treatment, analyzed relevant factors affecting drug efficacy, and compared the efficacy and safety with patients receiving Polymyxin B treatment. A total of 139 patients were included. Agranulocytosis, septic shock, SOFA score, and CAZ-AVI treatment course were independent risk factors affecting the prognosis of patients with CR-GNB infection treated with CAZ-AVI while prolonging the treatment course of CAZ-AVI was the only protective factor for bacterial clearance. The fundamental indicators showed no statistically significant differences between CAZ-AVI and Polymyxin B treatment groups. At the same time, the proportion of patients treated with monotherapy was significantly higher in the CAZ-AVI group than in the Polymyxin B group (37.2% vs. 8.9%, p < 0.05), the 30-day mortality rate of the CAZ-AVI treatment group (27.7% vs. 46.7%, p = 0.027) was lower than that of the Polymyxin B treatment group. The 30-day clinical cure rate (59.6% vs. 40% p = 0.030) and 14-day microbiological clearance rate (42.6% vs. 24.4%, p = 0.038) were significantly higher in the CAZ-AVI than in the Polymyxin B treatment group. Eighty nine patients were monitored for CAZ-AVI resistance, and the total resistance rate was 14.6% (13/89). The resistance rates of Carbapenem-resistant Klebsiella pneumoniae (CRKP) and Carbapenem-resistant Pseudomonas aeruginosa (CRPA) to CAZ-AVI were 13.5 and 15.4%, respectively. CAZ-AVI has shown high clinical efficacy and bacterial clearance in treating CR-GNB infections. Compared with Polymyxin B, CAZ-AVI significantly improved the outcome of mechanical ventilation in patients with septic shock, agranulocytosis, Intensive Care Unit (ICU) patients, bloodstream infection, and patients with SOFA score > 6, and had a lower incidence of adverse events. We monitored the emergence of CAZ-AVI resistance and should strengthen the monitoring of drug susceptibility in clinical practice and the rational selection of antibiotic regimens to delay the onset of resistance.

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

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. 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). 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. 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. 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 of ceftazidime-avibactam in solid organ transplant recipients with bloodstream infections caused by carbapenemase-producing Klebsiella pneumoniae

We aimed to compare the efficacy of ceftazidime-avibactam (CAZ-AVI) versus the best available therapy (BAT) in solid organ transplant (SOT) recipients with bloodstream infection caused by carbapenemase-producing Klebsiella pneumoniae (CPKP-BSI). A retrospective (2016-2021) observational cohort study was performed in 14 INCREMENT-SOT centers (ClinicalTrials.gov identifier: NCT02852902; Impact of Specific Antimicrobials and MIC Values on the Outcome of Bloodstream Infections Due to ESBL- or Carbapenemase-producing Enterobacterales in Solid Organ Transplantation: an Observational Multinational Study). Outcomes were 14-day and 30-day clinical success (complete resolution of attributable manifestations, adequate source control, and negative follow-up blood cultures) and 30-day all-cause mortality. Multivariable logistic and Cox regression analyses adjusted for the propensity score to receive CAZ-AVI were constructed. Among 210 SOT recipients with CPKP-BSI, 149 received active primary therapy with CAZ-AVI (66/149) or BAT (83/149). Patients treated with CAZ-AVI had higher 14-day (80.7% vs 60.6%, P = .011) and 30-day (83.1% vs 60.6%, P = .004) clinical success and lower 30-day mortality (13.25% vs 27.3%, P = .053) than those receiving BAT. In the adjusted analysis, CAZ-AVI increased the probability of 14-day (adjusted odds ratio [aOR], 2.65; 95% confidence interval [CI], 1.03-6.84; P = .044) and 30-day clinical success (aOR, 3.14; 95% CI, 1.17-8.40; P = .023). In contrast, CAZ-AVI therapy was not independently associated with 30-day mortality. In the CAZ-AVI group, combination therapy was not associated with better outcomes. In conclusion, CAZ-AVI may be considered a first-line treatment in SOT recipients with CPKP-BSI.

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

IntroductionThe 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).MethodsClinical 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.ResultsA 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.ConclusionsCAZ-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.

Effectiveness of ceftazidime–avibactam versus colistin in treating carbapenem-resistant Enterobacteriaceae bacteremia

IntroductionAntimicrobial treatments for carbapenem-resistant Enterobacteriaceae (CRE) bacteremia are limited, with colistin-based regimens being a primary therapy. Ceftazidime–avibactam is an emerging treatment for various CRE infections. Our study aimed to assess ceftazidime–avibactam effectiveness compared with colistin in patients with CRE bacteremia. MethodsThis retrospective, multi-centre study included adult patients with CRE bacteremia treated with ceftazidime–avibactam or colistin, between September 1, 2017 and December 1, 2020, at two tertiary centres in Saudi Arabia. The risk of 14-day mortality was compared between recipients of ceftazidime–avibactam versus colistin, using Cox multivariable regression, adjusted for Pitt score, Charlson index score, and treatment with chemotherapy and immunosuppressive agents. ResultsIn total, 61 patients were enrolled; 32 received ceftazidime–avibactam, and 29 received colistin. The adjusted risk for 14-day mortality was lower in the ceftazidime–avibactam group than the colistin group (hazard ratio [HR] 0.32; 95% confidence interval [CI] 0.10–0.99; p = 0.049), while the crude 14-day mortality did not differ between the two antibiotics (HR, 0.59; 95% CI 0.21–1.66; p = 0.32). The clinical success rate was higher with the use of ceftazidime–avibactam versus colistin (46.8% versus 20.4%, respectively; p = 0.047). ConclusionCeftazidime–avibactam was associated with a lower risk of 14-day mortality than colistin in patients with CRE bacteremia.

Ceftazidime-avibactam in the treatment of infections from carbapenem-resistant Klebsiella pneumoniae: Ceftazidime-avibactam against CR-KP infections

Clinical experience with ceftazidime-avibactam (CAZ-AVI) for the treatment of carbapenem-resistant Klebsiella pneumoniae (CR-KP) infections is not well evaluated. The aim of this study was to assess its efficacy in a single-centre cohort of patients infected with CR-KP. We conducted a retrospective observational study of consecutive patients treated for >72 h with CAZ-AVI or other active antibiotics (OAAs) for CR-KP infections. The primary outcome was 30-d mortality. The secondary outcomes were 14-d clinical failure and 14-d microbiological failure. Multivariate regression and propensity score matching were used to evaluate the relationship between CAZ-AVI treatment and outcomes. Ninety infections caused by CR-KP were documented in our study. Forty-two patients were treated with CAZ-AVI and 48 with OAAs. The crude 30-d mortality (8/42 vs. 22/48, P=0.007), 14-d clinical failure (14/42 vs. 24/48, P=0.046) and 14-d microbiological failure (11/42 vs. 15/48, P=0.034) were significantly lower in patients with CAZ-AVI treatment. The Kaplan-Meier survival curves of 30-d mortality confirmed the findings (logrank=0.004). In the multivariable models, the odds ratio (OR) of 30-d mortality (OR 0.23 95% CI 0.10-0.51, P<0.000), 14-d clinical failure (OR 0.37, 95% CI 0.14-0.95, P=0.039) and 14-d microbiological failure (OR 0.17, 95% CI 0.08-0.93, P=0.038) remain consistently significant. In the subgroup analysis, CAZ-AVI was associated with decreased 30-d mortality in the positive blood culture (OR 0.23, 95% CI 0.08-0.63, P=0.004), septic shock (OR 0.23, 95% CI 0.07-0.78, P=0.019), SOFA score (>5, OR 0.13, 95% CI 0.04-0.36, P<0.000), mechanical ventilation (OR 0.13, 95% CI 0.04-0.36, p<0.000) and Charlson comorbidity index (>3, OR 0.15, 95% CI 0.04-0.55, P=0.004). After propensity score matching, 29 cases from each group were well matched. The 30-d mortality remained significantly lower in the CAZ-AVI group (6/29 vs. 13/29, P=0.05). CAZ-AVI may be a more valuable therapeutic option for severe CR-KP infections than for mild cases and further randomized controlled trials are needed to evaluate the efficacy.

1592. Antimicrobial Activity of Ceftazidime-Avibactam and Comparator Agents Against Enterobacterales and Pseudomonas aeruginosa With Overexpression of AmpC β-Lactamase From Phase 3 Clinical Trials

BackgroundAmpC overproduction is a main mechanism of carbapenem resistance, in the absence of acquired carbapenemases. Ceftazidime-avibactam (CAZ-AVI) has potent in vitro activity against AmpC-producing P. aeruginosa and Enterobacterales that are resistant to carbapenems and other β-lactams.MethodsActivity of CAZ-AVI and comparators was evaluated against AmpC-overproducing Enterobacterales (n=77) and P. aeruginosa (n=53) collected from 4 CAZ-AVI clinical trials: RECLAIM (complicated intra-abdominal infection [cIAI]), REPRISE (cIAI/complicated urinary tract infection [cUTI]), RECAPTURE (cUTI) and REPROVE (hospital-acquired pneumonia/ventilator associated pneumonia). In vitro susceptibility of CAZ-AVI and comparators was performed by broth microdilution using ThermoFisher custom panels. CLSI breakpoints were used to determine susceptibility. Quantitative PCR and microarray data were used to characterize presence and expression of AmpC. Clinical response at test of cure was assessed.ResultsAgainst 77 AmpC-overproducing Enterobacterales isolates, meropenem-vaborbactam (MVB) (98.7% susceptible [S]), CAZ-AVI (96.1% S), and meropenem (MEM) (96.1% S) had similar in vitro activity (Table), with greater in vitro activity than amikacin (AMK) (84.4% S), gentamicin (61.0% S), and ceftolozane-tazobactam (TZC) (35.1% S). Clinical cures in patients with baseline AmpC-overproducing Enterobacterales were 21/26 (81%) in CAZ-AVI group vs 17/20 (85%) in control groups. Against 53 AmpC-overproducing P. aeruginosa isolates, CAZ-AVI (73.6% S) showed greater in vitro activity than AMK (69.8% S), TZC (58.5% S), and MEM (37.7% S). Clinical cures in patients with baseline AmpC-overproducing P. aeruginosa were 12/14 (86%) in CAZ-AVI group vs 9/12 (75%) in control groups. MIC distributions against the same P aeruginosa isolates were CAZ-AVI (MIC50/90, 4/ >64 µg/mL), MVB (MIC50/90, 8/32 µg/mL), and MEM (MIC50/90, 8/32 µg/mL).Table ConclusionCAZ-AVI was the most active agent against AmpC-overproducing P. aeruginosa with higher proportion of clinical cure than controls. CAZ-AVI was also among the most active agents against AmpC-overproducing Enterobacterales, with >96% isolates susceptible.DisclosuresLynn-Yao Lin, MS, AbbVie (Employee) Dmitri Debabov, PhD, AbbVie (Employee) William Chang, BS, AbbVie (Employee) Urania Rappo, MD, MS, PharmD, Allergan (before its acquisition by AbbVie) (Employee)

Novel β-Lactam/β-Lactamase Combination Versus Meropenem for Treating Nosocomial Pneumonia.

This study reports the integrated analysis of two phase III studies of novel β-lactam/β-lactamase combination versus meropenem for treating nosocomial pneumonia (NP) including ventilator-associated pneumonia (VAP). The ASPECT-NP trial compared the efficacy and safety of ceftolozane–tazobactam versus meropenem for treating NP/VAP. The REPROVE trial compared ceftazidime–avibactam and meropenem in the treatment of NP/VAP. A total of 1528 patients (361 in the ceftolozane–tazobactam group; 405 in the ceftazidime–avibactam group; 762 in the meropenem group) were analyzed. The clinical cure rates at test-of-cure among the novel β-lactam/β-lactamase combinations group were non-inferior to those of the meropenem (70.7% vs. 72.1%, risk difference (RD) −0.01, 95% confidence interval (CI) 0.06–0.05) in the clinical evaluable populations. Overall 28-day mortality did not differ between novel β-lactam/β-lactamase combinations and the meropenem group (RD, −0.02, 95% CI, −0.09 to 0.05). Regarding the microbiological eradication rate, novel β-lactam/β-lactamase combinations were non-inferior to meropenem for Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, Haemophilus influenzae, Staphylococcus marcescens, and Enterobacter cloacae. Finally, novel β-lactam/β-lactamase combinations had a similar risk of (i) treatment-emergent adverse events (RD, 0.02, 95% CI, −0.02 to 0.06), (ii) events leading to the discontinuation of the study drug (RD, 0.00, 95% CI, −0.02 to 0.03), (iii) severe adverse events (RD, 0.03, 95% CI, −0.01 to 0.07), and (iv) death (RD, 0.02, 95% CI, −0.02 to 0.05) when compared with meropenem group. In conclusion, our findings suggest that novel β-lactam/β-lactamase combinations of ceftolozane−tazobactam and ceftazidime–avibactam can be recommended as one of the therapeutic options in the treatment of NP/VAP.

662. Recurrence of Infection and Emergence of Drug Resistance After Treatment with Meropenem/Vaborbactam Compared with Ceftazidime/Avibactam in Carbapenem-Resistant Enterobacteriaceae Infections

BackgroundOptions for treatment of carbapenem-resistant Enterobacteriaceae (CRE) infections were historically limited to antibiotics with limited efficacy and significant toxicities. Ceftazidime/avibactam (CA) and meropenem/vaborbactam (MV) are superior to older regimens; however, a direct comparison of the agents is lacking. This study compared clinical outcomes including recurrence of infection and emergence of drug resistance in patients who received CA vs. MV for CRE infections.MethodsThis was a multicenter, retrospective cohort study of adults with CRE infections who received CA or MV for ≥72 hours from February 2015 to October 2018. Patients with localized urinary tract infection were excluded. The primary endpoint was clinical success (30-day survival, resolution of signs and symptoms of infection, sterilization of blood cultures within 7 days in patients with bacteremia, absence of recurrent infection). Secondary endpoints included 30- and 90-day mortality, adverse events (AE), recurrent CRE infection within 90 days, and development of resistance in patients with recurrent infection. We conducted a post hoc subgroup analysis in patients with recurrence to compare development of resistance in those who received CA monotherapy, CA combination therapy, and MV monotherapy.Results131 patients were included (CA: 105 patients, MV: 26 patients), 40% had bacteremia. No statistical difference in clinical success was observed between groups (62% vs. 69%, respectively, P = 0.49). Patients in the CA arm received combination therapy more often than patients in the MV arm (61% vs. 15%, P < 0.01). No difference in 30- and 90-day mortality resulted among groups, but numerically higher rates of AE were observed in the CA group (38% vs. 23%, P = 0.17). In patients with recurrent infection, development of resistance occurred more often with CA monotherapy, though not statistically significant (Table 1). One case of MV resistance was observed in a patient who had received 4 prior courses of MV, but this episode was outside of the study period.ConclusionClinical success was similar between the groups despite MV being used more often as monotherapy. Development of resistance and rates of AE were higher in the CA group compared with MV therapy. Disclosures All authors: No reported disclosures.

In vitro activity of ceftazidime-avibactam combined with colistin against extensively drug-resistant Pseudomonas aeruginosa

To evaluate the in vitro activity of ceftazidime-avibactam (CAZ-AVI) alone or in combination with colistin (COL) against clinically isolated extensively drug-resistant Pseudomonas aeruginosa (XDR-PA). Minimum inhibitory concentration (MIC) of 16 clinical XDR-PA isolates was determined by broth dilution method and chessboard design when CAZ-AVI and COL were used alone or in combination, then the combined inhibitory concentration index (FICI) was calculated. Class A [Klebsiella pneumoniae carbapenemase β-lactamase (blaKPC), Guiana extended-spectrum β-lactamase (blaGES)], Class B [imipenemase β-lactamase (blaIMP), Verona-Integronmetallo β-lactamase (blaVIM), New Delhi metallo β-lactamase (blaNDM), German imipenemase β-lactamase (blaGIM), Sao Paulo metallo-β-lactamase (blaSPM)], Class C [AmpC β-lactamase (blaAmpC)], Class D [oxacillinase β-lactamase (blaOXA)] β-lactamase-related resistance genes were detected by polymerase chain reaction. Drug-resistant mutation frequencies of each strain were determined on a drug-containing plate. The time kill curves of three XDR-PA were plotted by colony counting method. A biofilm model was established in vitro, and the synergistic effect of CAZ-AVI and COL on biofilm inhibition was detected by methythiazolyl tetrazolium assay (MTT). The MICs of 16 XDR-PA for CAZ-AVI ranged from 1 mg/L to 128 mg/L, and three of the isolates showed resistance (MIC > 8 mg/L). The FICI range of CAZ-AVI combined with COL was 0.312-1.000. Four isolates were synergistic, while the other 12 isolates were additive. Three isolates resistant to CAZ-AVI contained Class B resistance genes such as blaIMP and blaVIM, while 13 susceptible isolates carried resistance genes belonging to Class A, C or D. The logarithm values of mutation frequencies of drug resistance in CAZ-AVI group, COL group and combination group were -4.81±0.88, -7.06±0.69 and -9.70 (-9.78, -9.53), respectively. There were significant differences among the three groups (H = 33.601, P < 0.001), and between every two groups (adjusted P < 0.05). In time kill curves, the phytoplankton load of three XDR-PA decreased more than 6 log CFU/L when these two drugs were used together, and number of PA1819 planktonic bacteria decreased more than 5.1 log CFU/L compared with monotherapy group. Viable quantity in biofilm (A490) of normal saline group, CAZ-AVI group, COL group and CAZ-AVI-COL group were 0.665±0.068, 0.540±0.072, 0.494±0.642 and 0.317±0.080, respectively. There was significant difference between the other two groups (all P < 0.001), except for that between CAZ-AVI group and COL group (P = 0.109). CAZ-AVI combined with COL can effectively improve the bactericidal effect of each drug alone on XDR-PA. The regimen can also reduce the production of drug-resistant bacteria and inhibit the formation of biofilm. Therefore, it is a potential treatment for XDR-PA infection.

Efficacy of ceftazidime-avibactam in the treatment of infections due to Carbapenem-resistant Enterobacteriaceae

BackgroundCarbapenem-resistant Enterobacteriaceae (CRE) represent an important global threat. The aim of this study is to describe the clinical course and outcomes of patients with CRE infections treated with ceftazidime-avibactam (CAZ-AVI) compared to patients treated with other agents.MethodsA retrospective cohort study of patients with established CRE infections from January 2017 until August 2018 was conducted. All patients who received CAZ-AVI and all cultures with carbapenem-resistant isolates were screened. We compared patients who received CAZ-AVI for CRE infections with patients who received other agents.ResultsA total of 38 consecutive patients with CRE infections were identified. Age and baseline comorbidities were similar between the two groups. The median time from admission to isolation of CRE culture was 22.5 days in the CAZ-AVI group and 17 days in the comparative group (P = 0.7). The incidence of CRE bacteremia was similar between the two groups: 7 patients (70%) in the CAZ-AVI group and 15 patients (53.6%) in the comparative group (P = 0.47). The most common type of CRE infections in both groups was hospital acquired pneumonia (HAP). Klebsiella pneumoniae was the predominant pathogen in both groups. A carbapenemase gene was detected in 35 (92%) patients; the OXA-48 gene was the predominant gene identified in 28 (74%) isolates. Eight out of ten patients in the CAZ-AVI group and fifteen out of twenty-eight in the comparative group achieved clinical remission (P = 0.14). After thirty days, all-cause mortality was observed in five patients in the CAZ-AVI group and 16 patients in the comparative group, accounting for 50 and 57% respectively.ConclusionsIn patients with established OXA-48-type CRE infection, CAZ-AVI is a reasonable alternative to standard therapy. These findings need to be confirmed in prospective studies.

Safety and Efficacy of Ceftazidime–Avibactam in the Treatment of Children ≥3 Months to &lt;18 Years With Complicated Urinary Tract Infection: Results from a Phase 2 Randomized, Controlled Trial

Ceftazidime-avibactam is effective and well tolerated in adults with complicated urinary tract infection (cUTI), but has not been evaluated in children with cUTI. This single-blind, multicenter, active-controlled, phase 2 study (NCT02497781) randomized children ≥3 months to <18 years with cUTI (3:1) to receive intravenous (IV) ceftazidime-avibactam or cefepime for ≥72 hours, with subsequent optional oral switch. Total treatment duration was 7-14 days. Primary objective was assessment of safety. Secondary objectives included descriptive efficacy and pharmacokinetics. A blinded observer determined adverse event (AE) causality and clinical outcomes up to the late follow-up visit (20-36 days after the last dose of IV/oral therapy). In total, 95 children received ≥1 dose of IV study drug (ceftazidime-avibactam, n = 67; cefepime, n = 28). The predominant baseline Gram-negative uropathogen was Escherichia coli (92.2%). AEs occurred in 53.7% and 53.6% patients in the ceftazidime-avibactam and cefepime groups, respectively. Serious AEs occurred in 11.9% (ceftazidime-avibactam) and 7.1% (cefepime) patients. One serious AE (ceftazidime-avibactam group) was considered drug related. In the microbiologic intent-to-treat analysis set, favorable clinical response rates >95% were observed for both groups at end-of-IV and remained 88.9% (ceftazidime-avibactam) and 82.6% (cefepime) at test-of-cure. Favorable per-patient microbiologic response at test-of-cure was 79.6% (ceftazidime-avibactam) and 60.9% (cefepime). Ceftazidime-avibactam was well tolerated in children with cUTI, with a safety profile consistent with that of adults with cUTI and of ceftazidime alone, and appeared effective in children with cUTI due to Gram-negative pathogens.

2410. Clinical Outcomes Associated With Various Treatment Options for Infections Caused by Carbapenem-Resistant Enterobacteriaceae

BackgroundInfections caused by carbapenem-resistant Enterobacteriaceae (CRE) have been designated an urgent level threat to public health. With the advent of novel β lactam/β-lactamase inhibitor combinations, the armamentarium against CRE is expanding. Our study aims to evaluate clinical outcomes in patients with CRE infections.MethodsA retrospective study was conducted to compare clinical outcomes in adult patients with documented CRE infections between January 2009 and December 2017 and received either ceftazidime–avibactam (CAZ-AVI) or best available therapy (BAT). Best available therapy was defined as antimicrobials with susceptibility to the causative pathogen according to CLSI breakpoints. The following clinical outcomes were assessed: clinical cure, total length of stay (LOS), 30-day mortality, and infection-related mortality.ResultsOne hundred and fifty patients met criteria for inclusion; 25 in the CAZ-AVI group and 125 in the BAT group. The median Charlson Comorbidity Index (CCI) was 6 in both cohorts, indicating a low baseline probability for survival. The most common primary sites of infection for the CAZ-AVI and BAT cohorts, respectively, were the following: blood (24% vs. 18%, P = 0.580), urine (36% vs. 23%, P = 0.209), intraabdominal (16% vs. 14%, P = 0.754), and lung (12% vs. 27%, P = 0.132). Combination therapy was utilized in 8% of patients in the CAZ-AVI group compared with 42% in the BAT group. Combinations in the BAT group consisted of colistin-based (68%), tigecycline-based (13%), and aminoglycoside-based (13%) regimens. Although clinical cure rates were similar between both groups (80% vs. 72%, P = 0.469), there was a statistically significant difference in both all-cause mortality (24% vs. 73%, P = 0.006) and infection related mortality (4% vs. 26%, P = 0.017) in the CAZ-AVI and BAT groups, respectively. There was a trend toward a lower overall length of stay favoring the CAZ-AVI cohort as opposed to the BAT cohort (16 days vs. 30 days, P = 0.082).ConclusionCAZ-AVI therapy was associated with lower mortality rates for CRE infections and have a high attributable mortality, especially with concomitant bacteremia. Future studies are warranted to confirm these results.Disclosures All authors: No reported disclosures.

Ceftazidime-avibactam versus meropenem in nosocomial pneumonia, including ventilator-associated pneumonia (REPROVE): a randomised, double-blind, phase 3 non-inferiority trial

Nosocomial pneumonia is commonly associated with antimicrobial-resistant Gram-negative pathogens. We aimed to assess the efficacy and safety of ceftazidime-avibactam in patients with nosocomial pneumonia, including ventilator-associated pneumonia, compared with meropenem in a multinational, phase 3, double-blind, non-inferiority trial (REPROVE). Adults with nosocomial pneumonia (including ventilator-associated pneumonia), enrolled at 136 centres in 23 countries, were randomly assigned (1:1) to 2000 mg ceftazidime and 500 mg avibactam (by 2 h intravenous infusion every 8 h) or 1000 mg meropenem (by 30-min intravenous infusion every 8 h) for 7-14 days; regimens were adjusted for renal function. Computer-generated randomisation codes were stratified by infection type and geographical region with a block size of four. Participants and investigators were masked to treatment assignment. The primary endpoint was clinical cure at the test-of-cure visit (21-25 days after randomisation). Non-inferiority was concluded if the lower limit of the two-sided 95% CI for the treatment difference was greater than -12·5% in the coprimary clinically modified intention-to-treat and clinically evaluable populations. This trial is registered with ClinicalTrials.gov (NCT01808092) and EudraCT (2012-004006-96). Between April 13, 2013, and Dec 11, 2015, 879 patients were randomly assigned. 808 patients were included in the safety population, 726 were included in the clinically modified intention-to-treat population, and 527 were included in the clinically evaluable population. Predominant Gram-negative baseline pathogens in the microbiologically modified intention-to-treat population (n=355) were Klebsiella pneumoniae (37%) and Pseudomonas aeruginosa (30%); 28% were ceftazidime-non-susceptible. In the clinically modified intention-to-treat population, 245 (68·8%) of 356 patients in the ceftazidime-avibactam group were clinically cured, compared with 270 (73·0%) of 370 patients in the meropenem group (difference -4·2% [95% CI -10·8 to 2·5]). In the clinically evaluable population, 199 (77·4%) of 257 participants were clinically cured in the ceftazidime-avibactam group, compared with 211 (78·1%) of 270 in the meropenem group (difference -0·7% [95% CI -7·9 to 6·4]). Adverse events occurred in 302 (75%) of 405 patients in the ceftazidime-avibactam group versus 299 (74%) of 403 in the meropenem group (safety population), and were mostly mild or moderate in intensity and unrelated to study treatment. Serious adverse events occurred in 75 (19%) patients in the ceftazidime-avibactam group and 54 (13%) patients in the meropenem group. Four serious adverse events (all in the ceftazidime-avibactam group) were judged to be treatment related. Ceftazidime-avibactam was non-inferior to meropenem in the treatment of nosocomial pneumonia. These results support a role for ceftazidime-avibactam as a potential alternative to carbapenems in patients with nosocomial pneumonia (including ventilator-associated pneumonia) caused by Gram-negative pathogens. AstraZeneca.

Ceftazidime-avibactam or best available therapy in patients with ceftazidime-resistant Enterobacteriaceae and Pseudomonas aeruginosa complicated urinary tract infections or complicated intra-abdominal infections (REPRISE): a randomised, pathogen-directed, phase 3 study

Carbapenems are frequently the last line of defence in serious infections due to multidrug-resistant Gram-negative bacteria, but their use is threatened by the growing prevalence of carbapenemase-producing pathogens. Ceftazidime-avibactam is a potential new agent for use in such infections. We aimed to assess the efficacy, safety, and tolerability of ceftazidime-avibactam compared with best available therapy in patients with complicated urinary tract infection or complicated intra-abdominal infection due to ceftazidime-resistant Gram-negative pathogens. REPRISE was a pathogen-directed, international, randomised, open-label, phase 3 trial that recruited patients from hospitals across 16 countries worldwide. Eligible patients were aged 18-90 years with complicated urinary tract infection or complicated intra-abdominal infection caused by ceftazidime-resistant Enterobacteriaceae or Pseudomonas aeruginosa. Patients were randomised (1:1) to 5-21 days of treatment with either ceftazidime-avibactam (a combination of 2000 mg ceftazidime plus 500 mg avibactam, administered via a 2-h intravenous infusion every 8 h) or best available therapy. The primary endpoint was clinical response at the test-of-cure visit, 7-10 days after last infusion of study therapy, analysed in all patients who had at least one ceftazidime-resistant Gram-negative pathogen, as confirmed by the central laboratory, and who received at least one dose of study drug. Safety endpoints were assessed in all patients who received at least one dose of study drug. This study is registered with ClinicalTrials.gov, number NCT01644643. Between Jan 7, 2013, and Aug 29, 2014, 333 patients were randomly assigned, 165 to ceftazidime-avibactam and 168 to best available therapy. Of these, 154 assigned to ceftazidime-avibactam (144 with complicated urinary tract infection and ten with complicated intra-abdominal infection) and 148 assigned to best available therapy (137 with complicated urinary tract infection and 11 with complicated intra-abdominal infection) were analysed for the primary outcome. 163 (97%) of 168 patients in the best available therapy group received a carbapenem, 161 (96%) as monotherapy. The overall proportions of patients with a clinical cure at the test-of-cure visit were similar with ceftazidime-avibactam (140 [91%; 95% CI 85·6-94·7] of 154 patients) and best available therapy (135 [91%; 85·9-95·0] of 148 patients). 51 (31%) of 164 patients in the ceftazidime-avibactam group and 66 (39%) of 168 in the best available therapy group had an adverse event, most of which were mild or moderate in intensity. Gastrointestinal disorders were the most frequently reported treatment-emergent adverse events with both ceftazidime-avibactam (21 [13%] of 164 patients) and best available therapy (30 [18%] of 168 patients). No new safety concerns were identified for ceftazidime-avibactam. These results provide evidence of the efficacy of ceftazidime-avibactam as a potential alternative to carbapenems in patients with ceftazidime-resistant Enterobacteriaceae and P aeruginosa. AstraZeneca.