Safety and Efficacy of Ceftazidime-Avibactam Plus Metronidazole in the Treatment of Children ≥3 Months to <18 Years With Complicated Intra-Abdominal Infection: Results From a Phase 2, Randomized, Controlled Trial

Reserve antibiotics: overcoming limitations of evidence generated from regulatory approval trials

New antibiotics active against multidrug resistant bacteria (MDR-B) are licensed by regulatory agencies based on pivotal trials that serve the primary purpose of obtaining marketing-authorization. There is increasing concern that they do not offer guidance on how to best use new antibiotics, in which population, and to what extent they overcome existing resistance. We reviewed the literature for pre-approval studies (phase 2 and 3 randomized controlled trials) and post-approval studies (randomized and non-randomized controlled trials) evaluating efficacy and safety of new antibiotics, classified by WHO as Reserve, approved in the European Union and the US from January 2010 to May 2023. Substantial failures occur in generating evidence to guide routine clinical use: preapproval studies lack representativeness, select outcomes and comparators to chase statistical significance, and often avoid using prespecified analytical methods. Three recommendations are key to enhance the quality and relevance of clinical data underpinning use of last resort molecules on the WHO AWaRe Reserve list active against carbapenem-resistant MDR-B i). separation of pivotal trials from post-approval studies, which should be funded by public programs and de-linked from commercial purposes, ii). development and maintenance of a global infrastructure to conduct post-approval public health focused studies, and iii). development of trial platforms that use efficient, adaptive designs to inform clinical decision making and country level technology appraisal. These solutions will allow clinicians to determine whether recently approved Reserve antibiotics are not only "newer" but also "better" for vulnerable patient populations at particular risk for infections by MDR-B.

Efficacy of Ceftazidime-avibactam in treating Gram-negative infections: a systematic review and meta-analysis

INTRODUCTION

Ceftazidime-avibactam (CAZ-AVI) has emerged as a promising treatment option for Gram-negative infections, particularly those caused by CAZ-Non-Susceptible (NS) pathogens. This systematic review and meta-analysis aim to assess the efficacy and safety of CAZ-AVI in these challenging infections.

METHODS

We systematically queried EMBASE, Cochrane CENTRAL, and PubMed/Medline for studies published until September 15, 2024. Randomized Controlled Trials (RCTs) evaluating CAZ-AVI against Gram-negative infections were included. A meta-analysis was performed to calculate pooled odds ratios (OR) for both clinical and microbiological success.

RESULTS

A total of 146 studies were identified through database searches, leading to the inclusion of 17 studies. Among the efficacy studies for Gram-negative pathogens, there was no significant difference in clinical success rates for CAZ-AVI compared to comparators (pooled OR: 0.90, p = 0.22), and a non-significant increase in microbiological success was observed (pooled OR: 1.20, p = 0.41). In contrast, for CAZ-NS pathogens, six studies reported no significant difference in clinical cure rates (pooled OR: 0.77, p = 0.24), while four studies indicated a non-significant increase in microbiological cure rates (pooled OR: 1.83, p < 0.02).

CONCLUSIONS

This study suggests that CAZ-AVI is a viable option for treating Gram-negative infections, including CAZ-NS pathogens. While it has shown promising activity against these resistant pathogens, its clinical and microbiological success rates are comparable to other antibiotics in the overall analysis. However, CAZ-AVI may offer an advantage in managing resistant infections. These findings underscore the need to consider CAZ-AVI in treatment guidelines and emphasize the importance of antibiotic stewardship programs to optimize its use and prevent resistance. Ongoing monitoring of resistance patterns and patient outcomes is essential to ensure its long-term efficacy.

Experience in Ceftazidime-Avibactam for treatment of MDR BGN infection in Oncologic Children

BACKGROUND

Ceftazidime-Avibactam (CAZ-AVI) plays a key role in the treatment of Multidrug Resistant Gram-Negative Bacilli (MDR-GNB) infections. In pediatrics, CAZ-AVI is clinically approved for treatment of urinary tract or intra-abdominal infection. However, there is limited data available about its use in children with cancer who have complicated infections caused by MDR-GNB.

OBJECTIVE

This study aims to describe our experience in using CAZ-AVI for the treatment of MDR GNB infections in children with cancer.

METHODS

This retrospective observational study was conducted at the Pediatric Oncology Institute (IOP/GRAACC/UNIFESP), including pediatric oncologic patients who received CAZ-AVI for the treatment of infections caused by GNB.

RESULTS

From Jan/2021 to Jun/2022, 11 patients with 13 episodes were included in the analysis. Among them, 45 % were female, with a median age of 7 years. Three patients had Acute lymphoblastic Leukemia (ALL), three had Acute Myeloid Leukemia (AML), two had Non-Hodgkin Lymphoma (NHL). Additionally, there was one case each of medulloblastoma, fibrosarcoma, and craniopharyngioma. All patients presented significant risk factors for MDR-GNB, such as neutropenia and two were submitted to Hematopoietic Stem Cell Transplantation (HSCT). The infection episodes included six Bloodstream Infections (BSI), two Urinary Tract Infections (UTI), two tracheobronchitis cases, along with one case each of necrotizing pneumonia, ventriculitis, and endocarditis. The identified pathogens included Klebsiella pneumoniae, Pseudomonas spp., Enterobacter cloacae, and Stenotrophomonas maltophilia. The primary reason for prescribing CAZ-AVI was either Multidrug-Resistant Gram-Negative Bacteria (MDR-GNB) infection or clinical worsening after initial therapy. Combination therapy was prescribed in eight episodes with a median prescription length of nine days. Microbiological sterilization was achieved in 92 % of episodes, and the 30-day survival rate was 84 %. Notably, no deaths were associated with treatment failure, and no adverse events associated with CAZ-AVI use were observed.

CONCLUSION

CAZ-AVI could be used for treating GNB infections in oncologic pediatric patients.

Ceftazidime/Avibactam for the Treatment of Infections in Children: A Case Series of Real-World Use

Ceftazidime/avibactam (CAZ/AVI) is effective against a wide range of carbapenem-resistant Enterobacterales and multidrug-resistant Pseudomonas. The European Medicines Agency (EMA) approved its use in children from 3 months of age for urinary tract (UTI) and intra-abdominal infections (IAI). Published data in children are limited. We performed a review of existing literature on the use of CAZ/AVI in children. Our search identified a phase I dose-exploratory trial, two registrational phase II clinical trials and nine real-world case series. The efficacy, adverse effects and pharmacokinetics of CAZ/AVI in children were summarized. We also describe the experience of the use of CAZ/AVI in a tertiary hospital in Madrid, Spain. Up to March 2023, 22 episodes of treatment with CAZ/AVI were recorded in 14 patients (50% female, with a median age of 4 years [interquartile range (IQR) 3.5-9]). UTI, bacteraemia or sepsis were the most common clinical conditions for which CAZ/AVI was prescribed. CAZ/AVI was started as targeted therapy in 10 paediatric patients and as empirical therapy in 12 (54.5%) children. The treatment indication was reviewed and adapted according to microbiological results by a paediatric infectious diseases team. Effectiveness of CAZ/AVI was adequate, and there were no discontinuations in any case because of adverse effects.

Evaluation of Ceftazidime-avibactam and Ceftolozane-tazobactam Prescriptions in a Tertiary Hospital for Children in France: An Observational Study, 2017-2022

BACKGROUND

Infections caused by drug-resistant Gram-negative bacteria, including carbapenem-resistant Enterobacterales and Pseudomonas aeruginosa, are emerging in pediatric hospitals. New ß-lactam/ ß-lactamase inhibitor combinations exhibit activity against these pathogens; however, there is limited data regarding their use in pediatric populations.

OBJECTIVES

The study aimed to describe the characteristics of ceftazidime-avibactam (CAZ/AVI) and ceftolozane-tazobactam (C/T) prescriptions in children and assess their appropriateness.

METHODS

We retrospectively analyzed all CAZ/AVI or C/T prescriptions in children hospitalized in a French tertiary hospital between 2017 and 2022. All clinical, biological, and pharmacological data were collected prospectively as part of the antibiotic monitoring program set up by our antimicrobial stewardship (AMS) team.

RESULTS

In total, 50 CAZ/AVI and 25 C/T prescriptions were recorded, which concerned 21 and 20 patients, respectively. All patients had an underlying chronic condition. Most prescriptions originated from Pediatric Intensive Care Units and the Department of Pediatric Pulmonology and were mainly initiated for respiratory tract infections (n = 41/50, 82% of the CAZ/AVI prescriptions and n = 14/25, 56% of the C/T prescriptions). P. aeruginosa was the primary pathogen in documented infections for both CAZ/AVI and C/T prescriptions (n = 26/48, 54% and n = 16/19, 84%, respectively). Almost all prescriptions of CAZ/AVI and C/T were considered appropriate (n = 47/50, 94% for CAZ/AVI and n = 23/25, 92% for C/T, respectively) by the AMS team. Both CAZ/AVI and C/T treatments were well tolerated and resulted in clinical success in 33 (66%) and 19 (76%) cases, respectively.

CONCLUSION

Our study suggests that CAZ/AVI and C/T are reasonable treatment options for children infected with Gram-negative pathogens resistant to carbapenems.

Suggested Dosing of Select Beta-lactam Agents for the Treatment of Antimicrobial-Resistant Gram-Negative Infections in Children

The Infectious Diseases Society of America (IDSA) publishes annual guidance on the treatment of antimicrobial-resistant (AMR) gram-negative infections. Within the AMR guidance, suggested dosages of antibiotics for adults infected with AMR pathogens are provided. This document serves as a companion document to the IDSA guidance to assist pediatric specialists with dosing β-lactam agents for the treatment of AMR infections in children. A panel of 13 pediatric infectious diseases specialists, including 11 pharmacists and 2 physicians, reviewed existing pharmacokinetic/pharmacodynamic, animal, and clinical data for newer β-lactam agents that are available in the United States and suggested for the treatment of AMR infections (ie, cefiderocol, ceftazidime-avibactam, ceftazidime-avibactam and aztreonam, ceftolozane-tazobactam, imipenem-cilastatin-relebactam, meropenem-vaborbactam, sulbactam-durlobactam). Suggested dosing for ampicillin-sulbactam is also provided, given complexities in dosing for carbapenem-resistant Acinetobacter baumannii infections. Consensus-based suggested dosing for β-lactam agents used to treat AMR infections in neonates, infants, children, and adolescents and relevant supporting evidence are provided. Content is up to date as of December 1, 2024. Gaps and limitations to existing data are discussed. Optimizing antibiotic dosing is critical to improving the outcomes of children with AMR infections.

Clinical experience with ceftazidime/avibactam for the treatment of extensively drug-resistant or pandrug-resistant Klebsiella pneumoniae in neonates and children

PURPOSE

Klebsiella pneumoniae is a significant cause of healthcare-associated infections, resulting in high morbidity and mortality rates due to limited treatment options. In this study, we aimed to evaluate the treatment outcomes and the safety of Ceftazidime-avibactam in infections caused by extensively drug-resistant or pandrug-resistant Klebsiella pneumoniae in pediatric patients.

METHODS

This study included pediatric patients who received ceftazidime-avibactam treatment due to extensively drug-resistant or pandrug-resistant Klebsiella pneumoniae infections, monitored in the pediatric intensive care, neonatal intensive care, and pediatric wards of Cukurova University Faculty of Medicine between 2022 and 2023. Patients' microbiological responses, clinical responses, medication side effects, and 30-day survival rates were evaluated.

RESULTS

Eleven pediatric patients were included in the study, of whom nine were male (81.8%). The median age at the initiation of ceftazidime-avibactam treatment was 15 months (range: 14 days-183 months). Sepsis was diagnosed in 9 patients (81.8%). Two premature infants (27 and 35 weeks) were admitted to the neonatal ICU. Regarding the Klebsiella pneumoniae strains, 10 (91%) were extensively drug-resistant (XDR), and 1 (9%) was pandrug-resistant (PDR). Eight strains (72.7%) were carbapenem-resistant, and 9 (81.8%) were colistin-resistant. Microbiological response was noted in 8 patients (72.7%), clinical response was evident in 6 patients (54.5%). The 30-day survival rate was 54.5%, with six patients surviving.

CONCLUSION

In our study, ceftazidime-avibactam has been identified as a significant treatment option for resistant Klebsiella pneumoniae infection in critically ill children and premature infants with sepsis and organ failure, and it has been found to be well tolerated.

The Use of Ceftazidime-Avibactam in a Pediatric Intensive Care Unit-An Observational Prospective Study

Background/objectives: Infections caused by carbapenem-resistant Enterobacterales (CRE) are progressively increasing in Pediatric Intensive Care Units (PICUs). Its treatment is challenging due to the lack of pediatric trials. CRE infections are associated with significantly poor outcomes, but ceftazidime-avibactam (CAZ-AVI) has been reported to be successful in their treatment. This study aimed to describe the use and outcome of CAZ-AVI in a PICU. Results: Ten patients were included, with 12 episodes of clinical suspicion or confirmed multidrug-resistant (MDR) bacterial infections treated with CAZ-AVI for surgical prophylaxis, suspicion of sepsis, pneumonia, and surgical wound infection. Of these patients, 80% received empirical treatment because of previous MDR bacterial colonization, and 60% were administrated combination therapy with aztreonam for Metallo-β-Lactamases (MBL)strains. No bacteria were resistant to CAZ-AVI. The average duration of the treatment was 3 days when cultures turned negative and 7 days when MDR bacteria were isolated. Methods: This was an observational prospective study of children treated with CAZ-AVI in the PICU of a tertiary hospital in 2022. Epidemiological, clinical, microbiological, and outcome data were collected. Conclusions: The most frequent use of CAZ-AVI in our PICU was the short-term empirical treatment for patients with previous MDR bacterial colonization and clinical suspicion of bacteremia or sepsis. Furthermore, the combination of CAZ-AVI plus aztreonam could be more effective for CRE infections, especially type Ambler class B as MBL strains.

Ceftazidime-Avibactam Use in a Case Series of Difficult-to-Treat or Recurrent Infections in Pediatric Patients with Complex Chronic Conditions: Effectiveness and Absence of Resistance Development

The prevalence of multidrug-resistant Gram-negative infections, particularly carbapenem-resistant strains, has become a significant global health concern. Ceftazidime-avibactam (CZA) has emerged as a promising treatment option. However, data on its efficacy and safety in children are scarce, necessitating further investigation. We conducted a descriptive case series at a tertiary hospital in Spain from February 2019 to January 2022. Pediatric patients (<16 years) treated with CZA for confirmed or suspected multidrug-resistant Gram-negative infections were included. The clinical and microbiological characteristics, treatment approaches, and outcomes were examined. Eighteen children received CZA treatment. All had complex chronic conditions, with the most frequent underlying main diseases being liver transplantation (n = 8) and biliary atresia (n = 4). The predominant type of infection for which they received CZA was intra-abdominal infection caused or suspected to be caused by OXA-48-producing Klebsiella pneumoniae. CZA was generally well tolerated. Within the first month of starting CZA therapy, two patients died, with one case directly linked to the infection's fatal outcome. Some patients needed repeated courses of therapy due to recurrent infections, yet no resistance development was noted. In summary, the use of CZA showed effectiveness and safety, while the lack of resistance development highlights CZA's potential as a primary treatment option against OXA-48-producing infections.

Friends or foes? Novel antimicrobials tackling MDR/XDR Gram-negative bacteria: a systematic review

Gram-negative bacteria have been one of the most studied classes in the field of microbiology, especially in the context of globally alarming antimicrobial resistance levels to these pathogens over the course of the past decades. With high numbers of these microorganisms being described as multidrug-resistant (MDR), or even extended-drug-resistant (XDR) bacteria, specialists in the field have been struggling to keep up with higher prevalence of difficult-to-treat infections caused by such superbugs. The FDA approval of novel antimicrobials, such as cefiderocol (FDC), ceftolozane/tazobactam (C/T), ceftazidime/avibactam (CZA), imipenem/relebactam (IMR), sulbactam/durlobactam (SUL-DUR) and phase 3 clinical trials' results of aztreonam/avibactam (ATM-AVI) has proven that, while all these substances provide encouraging efficacy rates, antibiotic resistance keeps up with the pace of drug development. Microorganisms have developed more extensive mechanisms of resistance in order to target the threat posed by these novel antimicrobials, thus equiring researchers to be on a constant lookout for other potential drug candidates and molecule development. However, these strategies require a proper understanding of bacterial resistance mechanisms to gain a comprehensive outlook on the issue. The present review aims to highlight these six antibiotic agents, which have brought hope to clinicians during the past decade, discussing general properties of these substances, as well as mechanisms and patterns of resistance, while also providing a short overview on further directions in the field.

Systematic review registration

https://www.crd.york.ac.uk/prospero/#searchadvanced, Identifier CRD42024505832.

Off-label Use of Ceftazidime/Avibactam in Neonatal Intensive Care Unit: A Real-life Experience and Literature Review

BACKGROUND

Multi/extensively drug-resistant bacterial infections have recently increased and new antimicrobial options are needed for difficult-to-treat infections. Ceftazidime/avibactam (CZA) has been approved for patients 3 months to 18 years of age, but real-life data on its off-label use in neonates and young infants are still scarce.

MATERIALS

We report demographic, clinical and microbiologic data as well as outcome and safety of all cases of infants treated with CZA between January 1, 2021 and September 30, 2022 in a tertiary neonatal intensive care unit. We also review all neonatal cases previously reported.

RESULTS

Twenty-one patients [17 males, with median gestational age 29 +2 (IQR 6 +6 ) weeks] received 31 CZA courses at a dose of 20-50 mg/kg/dose of ceftazidime q8h for suspected or proved multi/extensively drug-resistant infections. Median postnatal age at the onset of treatment was 44 days (IQR: 94 days). Twelve bacteremias, 2 urinary tract infections and 1 ventilator-acquired pneumonia were recorded. Twelve (39%) treatments were targeted, while 19 (61%) were empirically started due to known colonization with Klebsiella pneumoniae carbapenemase-producing Gram-negative bacteria. All patients had received multiple antibiotics prior and concomitantly with CZA. The most common pathogen identified at targeted administrations was carbapenem-resistant Klebsiella pneumoniae (83%). No serious adverse events attributed to the drug were detected. Twenty-one courses of CZA administration to 20 neonates with a median gestational age of 28.5 (IQR 3.5) weeks were previously reported without significant related adverse events.

CONCLUSIONS

Favorable clinical and microbiologic responses in neonatal intensive care unit patients treated with CZA off-label were observed without significant and unexpected adverse events in critically ill neonates.

Ceftazidime-avibactam induced renal disorders: past and present

With the increasing prevalence of multidrug-resistant Gram-negative bacterial pathogens worldwide, antimicrobial resistance has become a significant public health concern. Ceftazidime-avibactam (CAZ-AVI) exhibited excellent in vitro activity against many carbapenemase-producing pathogens, and was widely used for the treatment of various complicated infections. CAZ-AVI is well tolerated across all dosing regimens, and its associated acute kidney injury (AKI) in phase II/III clinical trials is rare. However, recent real-world studies have demonstrated that CAZ-AVI associated AKI was more frequent in real-world than in phase II and III clinical trials, particularly in patients receiving concomitant nephrotoxic agents, with critically ill patients being at a higher risk. Herein, we reviewed the safety data related to renal impairment of CAZ-AVI, and discussed its pharmacokinetic/pharmacodynamic targets and dosage adjustment in patients with impaired renal function. This review aimed to emphasize the importance for healthcare professionals to be aware of this adverse event of CAZ-AVI and provide practical insights into the dosage optimization in critically ill patients with renal dysfunction.

In vitro activity of ceftazidime-avibactam against Gram-negative strains in Chile 2015-2021

OBJECTIVES

Ceftazidime-avibactam (CAZ-AVI) combines ceftazidime and a reversible β-lactamase inhibitor that has shown activity against multidrug-resistant (MDR) Enterobacterales and P. aeruginosa. Using data from the Antimicrobial Testing Leadership and Surveillance program (ATLAS), this study examined the in vitro antimicrobial activity of CAZ-AVI and other antibiotics against Gram-negative bacteria collected from Chilean hospitals between 2015 and 2021.

METHODS

Clinical isolates of Enterobacterales and P. aeruginosa were collected from three medical centres in Chile. Blood, abdominal fluid, urine, soft tissues, and respiratory tract samples were obtained from infected patients. Minimum inhibitory concentrations using the broth microdilution method were determined for susceptibility testing, and the Clinical and Laboratory Standards Institute (CLSI) breakpoints were used for interpreting the results. Extended-spectrum β-lactamases (ESBL) and carbapenemase genes were also detected through polymerase chain reaction.

RESULTS

A total of 2600 Enterobacterales and 836 P. aeruginosa were analysed. CAZ-AVI was the antibiotic with the highest in vitro activity against Enterobacterales (99.72%). The incidence of carbapenem-resistant Enterobacterales (CRE) was 1.5% (n = 39), and the antibiotics with the best in vitro activity were tigecycline (92.31%), CAZ-AVI (88.57%), and amikacin (79.49%). CAZ-AVI was the antibiotic with the best activity against ESBL-producing Enterobacterales (99.34%) and MDR Enterobacterales (99.31%). For KPC-producing Enterobacterales, susceptibility to amikacin was 100%, whereas susceptibility to CAZ-AVI was 91.67%. Regarding MDR and difficult-to-treat resistance P. aeruginosa, 44.83% and 38.99% were susceptible to CAZ-AVI, respectively.

CONCLUSION

CAZ-AVI shows excellent in vitro activity against Enterobacterales in general, CRE, ESBL-producing Enterobacterales, and KPC-producing Enterobacterales. CAZ-AVI is also an option against MDR P. aeruginosa.

Physicochemical Characteristics of Antimicrobials and Practical Recommendations for Intravenous Administration: A Systematic Review

Most antimicrobial drugs need an intravenous (IV) administration to achieve maximum efficacy against target pathogens. IV administration is related to complications, such as tissue infiltration and thrombo-phlebitis. This systematic review aims to provide practical recommendations about diluent, pH, osmolarity, dosage, infusion rate, vesicant properties, and phlebitis rate of the most commonly used antimicrobial drugs evaluated in randomized controlled studies (RCT) till 31 March 2023. The authors searched for available IV antimicrobial drugs in RCT in PUBMED EMBASE®, EBSCO® CINAHL®, and the Cochrane Controlled Clinical trials. Drugs' chemical features were searched online, in drug data sheets, and in scientific papers, establishing that the drugs with a pH of <5 or >9, osmolarity >600 mOsm/L, high incidence of phlebitis reported in the literature, and vesicant drugs need the adoption of utmost caution during administration. We evaluated 931 papers; 232 studies were included. A total of 82 antimicrobials were identified. Regarding antibiotics, 37 reach the "caution" criterion, as well as seven antivirals, 10 antifungals, and three antiprotozoals. In this subgroup of antimicrobials, the correct vascular access device (VAD) selection is essential to avoid complications due to the administration through a peripheral vein. Knowing the physicochemical characteristics of antimicrobials is crucial to improve the patient's safety significantly, thus avoiding administration errors and local side effects.

Off-Label Use of Ceftazidime/Avibactam for the Treatment of Pan-Drug-Resistant Klebsiella pneumoniae in a Neonate: Case Report and Literature Review

BACKGROUND

Klebsiella pneumoniae is among the most common Gram-negative bacteria isolated to neonatal intensive care units (NICU) and one of the leading causes of morbidity and mortality. The ceftazidime/avibactam (CAZ-AVI) combination is approved for infections caused by aerobic Gram-negative organisms. It is licensed for use in infants over 3 months old. There are no safety and efficacy data regarding the administration of CAZ-AVI to infants younger than 3 months, except for a few case reports.

CASE PRESENTATION

This report describes a severely intoxicated 24-day-old, full-term, male neonate transferred to NICU level III from a secondary maternity hospital due to the deterioration of his general condition. On day four of admission, blood culture revealed the pan-drug-resistant (PDR) K. pneumoniae ss. pneumoniae, susceptible only to CAZ-AVI, which thus represented the only treatment option. Off-label CAZ-AVI was administered intravenously as a salvage therapy.

CONCLUSIONS

In healthcare settings, treating resistant K. pneumoniae presents serious challenges, especially in NICU patients. The off-label treatment with CAZ-AVI for 17 days was safe and effective in this one-month-old patient. A year later, the patient was healthy with normal cognitive development.

New Antimicrobials for the Treatment of Neonatal Sepsis Caused by Multi-Drug-Resistant Bacteria: A Systematic Review

BACKGROUND

Infections by multi-drug-resistant (MDR) organisms are sharply increasing in newborns worldwide. In low and middle-income countries, a disproportionate amount of neonatal sepsis caused by MDR Gram negatives was recently reported. Newborns with infections by MDR organisms with limited treatment options may benefit from novel antimicrobials.

METHODS

We performed a literature search investigating the use in newborns, infants and children of novel antimicrobials for the treatment of MDR Gram negatives, namely ceftazidime/avibactam, ceftolozane/tazobactam, cefiderocol, meropenem/vaborbactam, imipenem/relebactam, and Gram positives with resistance of concern, namely ceftaroline and dalbavancin. PubMed, EMBASE, and Web of Science were searched.

RESULTS

A total of 50 records fulfilled the inclusion criteria. Most articles were case reports or case series, and ceftazidime/avibactam was the most studied agent. All studies showed favorable efficacy and safety profile in newborns and across different age cohorts.

CONCLUSIONS

novel antibiotics may be considered in newborns for the treatment of MDR Gram negatives with limited treatment options and for Gram positives with resistance concerns. Further studies are needed to address their effectiveness and safety in newborns.

All Roads Lead to Rome: Enhancing the Probability of Target Attainment with Different Pharmacokinetic/Pharmacodynamic Modelling Approaches

In light of rising antimicrobial resistance and a decreasing number of antibiotics with novel modes of action, it is of utmost importance to accelerate development of novel treatment options. One aspect of acceleration is to understand pharmacokinetics (PK) and pharmacodynamics (PD) of drugs and to assess the probability of target attainment (PTA). Several in vitro and in vivo methods are deployed to determine these parameters, such as time-kill-curves, hollow-fiber infection models or animal models. However, to date the use of in silico methods to predict PK/PD and PTA is increasing. Since there is not just one way to perform the in silico analysis, we embarked on reviewing for which indications and how PK and PK/PD models as well as PTA analysis has been used to contribute to the understanding of the PK and PD of a drug. Therefore, we examined four recent examples in more detail, namely ceftazidime-avibactam, omadacycline, gepotidacin and zoliflodacin as well as cefiderocol. Whereas the first two compound classes mainly relied on the ‘classical’ development path and PK/PD was only deployed after approval, cefiderocol highly profited from in silico techniques that led to its approval. Finally, this review shall highlight current developments and possibilities to accelerate drug development, especially for anti-infectives.

Review of novel β-lactams and β-lactam/β-lactamase inhibitor combinations with implications for pediatric use

Antimicrobial resistance continues to surmount increasing concern globally, and treatment of difficult-to-treat (DTR) Pseudomonas aeruginosa, carbapenem-resistant (CR) Acinetobacter baumannii (CRAB), and CR Enterobacterales (CRE) remains a challenge for clinicians. Although previously rare, the incidence of multidrug-resistant (MDR) and CR infections in pediatric patients has increased drastically in the last decade and is associated with increased morbidity and mortality. To combat this issue, 14 novel antibiotics, including three β-lactam/novel β-lactamase inhibitor combinations (βL-βLIs) and two novel β-lactams (βLs), have received approval from the United States Food and Drug Administration since 2010. Improving clinician understanding of the utility of these novel therapies is imperative to improve judicious decision-making and prevent societal regression to a pre-penicillin era. In this review, we summarize the pharmacokinetic/pharmacodynamic (PK/PD) properties, clinical efficacy and safety data, dosing considerations, and subsequent role in therapy for ceftazidime-avibactam (CAZ-AVI), meropenem-vaborbactam (MER-VAB), imipenem-cilastatin-relebactam (IMI-REL), ceftolozane-tazobactam (TOL-TAZ), and cefiderocol in pediatric patients.

Population Pharmacokinetic Modeling for Ceftazidime-Avibactam Renal Dose Adjustments in Pediatric Patients 3 months and Older

Ceftazidime-avibactam is a novel β-lactam/β-lactamase inhibitor combination developed to treat serious Gram-negative bacterial infections; approved indications include complicated urinary tract infection, complicated intra-abdominal infection, and hospital-acquired pneumonia including ventilator-associated pneumonia in patients ≥ 3 months old. Because of the predominantly renal clearance of ceftazidime and avibactam, dose adjustments (reductions) are required for patients with estimated creatinine clearance (CrCL) ≤ 50 mL/min. We describe the application of combined adult and pediatric population pharmacokinetic models in developing ceftazidime-avibactam dose recommendations for pediatric patients ≥ 2 to < 18 years old with body surface area-normalized CrCL ≤ 50 mL/min/1.73 m² , including moderate, severe, or very severe renal impairment, or end-stage renal disease requiring hemodialysis, and for patients ≥ 3 months to < 2 years old with mild, moderate, or severe renal impairment. Models included allometric scaling for all subjects and simulations (1,000 subjects per age group, renal function group, and indication) were performed nonparametrically using post hoc random effects. Doses were selected based on simulated pediatric patients achieving steady-state exposures similar to adults and high probability of target attainment (using a simultaneous joint target for both ceftazidime and avibactam). Because there were few children with renal impairment in the ceftazidime-avibactam clinical trials, selected pediatric doses were guided by extrapolation and matching of adult exposures associated with efficacy and within established safety margins. The recommended doses for pediatric patients with estimated CrCL ≤ 50 mL/min/1.73 m² use equivalent adjustments in dose quantity and/or administration interval (vs. the corresponding age group with normal renal function) as those for adults.

Therapeutic Options and Outcomes for the Treatment of Neonates and Preterms with Gram-Negative Multidrug-Resistant Bacteria: A Systematic Review

(1) Background: Infections caused by multidrug-resistant (MDR) or extensively drug-resistant (XDR) bacteria represent a challenge in the neonatal population due to disease severity and limited therapeutic possibilities compared to adults. The spread of antimicrobial resistance and drug availability differ significantly worldwide. The incidence of MDR bacteria has constantly risen, causing an increase in morbidity, mortality, and healthcare costs in both high-income (HIC) and low- and middle-income countries (LMIC). Therefore, more evidence is needed to define the possible use of newer molecules and to optimize combination regimens for the oldest antimicrobials in neonates. This systematic review aims to identify and critically appraise the current antimicrobial treatment options and the relative outcomes for MDR and XDR Gram-negative bacterial infections in the neonatal population. (2) Methods: A literature search for the treatment of MDR Gram-negative bacterial infections in neonates (term and preterm) was conducted in Embase, MEDLINE, and Cochrane Library. Studies reporting data on single-patient-level outcomes related to a specific antibiotic treatment for MDR Gram-negative bacterial infection in children were included. Studies reporting data from adults and children were included if single-neonate-level information could be identified. We focused our research on four MDROs: Enterobacterales producing extended-spectrum beta-lactamase (ESBL) or carbapenemase (CRE), Pseudomonas aeruginosa, and Acinetobacter baumannii. PROSPERO registration: CRD42022346739 (3) Results: The search identified 11,740 studies (since January 2000), of which 22 fulfilled both the inclusion and exclusion criteria and were included in the analysis. Twenty of these studies were conducted in LMIC. Colistin is the main studied and used molecule to treat Gram-negative MDR bacteria for neonate patients in the last two decades, especially in LMIC, with variable evidence of efficacy. Carbapenems are still the leading antibiotics for ESBL Enterobacterales, while newer molecules (i.e., beta-lactam agents/beta-lactamase inhibitor combination) are promising across all analyzed categories, but data are few and limited to HICs. (4) Conclusions: Data about the treatment of Gram-negative MDR bacteria in the neonatal population are heterogeneous and limited mainly to older antimicrobials. Newer drugs are promising but not affordable yet for many LMICs. Therefore, strategies cannot be generalized but will differ according to the country’s epidemiology and resources. More extensive studies are needed to include new antimicrobials and optimize the combination strategies for the older ones.

Ceftazidime-Avibactam as Salvage Therapy in Pediatric Liver Transplantation Patients with Infections Caused by Carbapenem-Resistant Enterobacterales

Objective

There are few therapeutic options for infections caused by carbapenem-resistant Enterobacterales (CRE) in children following liver transplantation. Ceftazidime-avibactam (CAZ-AVI), a recently licensed antibacterial in China, was utilized as a salvage therapy against CRE in our center, and its efficacy and safety were therefore assessed.

Methods

The retrospective, observational study was conducted at the First Affiliated Hospital of Zhejiang University. Pediatric liver transplantation patients (≤12 years) who received CAZ-AVI as a salvage therapy against CRE infections were included from January 2020 to December 2021. Clinical success and all-cause death during hospitalization were the primary outcomes. Recurrence of infection, drug-related adverse events, and changes in inflammatory biomarkers were collected.

Results

Six children were enrolled, with a median age of 10.1 (interquartile range (IQR) 5.5–13.8) months. Primary intraperitoneal infections occurred in all patients, with five patients developing bloodstream infections. KPC carbapenemases were detected in most isolates, and the susceptibility results showed general sensitivity to tigecycline, polymyxin B, and CAZ-AVI. Tigecycline-based therapy was taken as the initial treatment and withdrawn because of clinical failure (5 cases) or cholestasis (1 case). After CRE infection, the median time to convert to CAZ-AVI was 7.5 (IQR 7.0–8.8) days, and the median CAZ-AVI treatment length was 21.0 (IQR 20.3–28.5) days. Clinical success was achieved in all patients, with a zero percent all-cause death rate. No CRE infections recurred throughout hospitalization, and no resistance to CAZ-AVI was detected. Patients experienced vomiting (1/6), skin rash (1/6), and a transient increase in cystatin C (2/6), γ-glutamyltransferase (2/6), and alkaline phosphatase (3/6).

Conclusion

CAZ-AVI was shown to be a successful salvage treatment for CRE infection in pediatric liver transplant recipients, with minor and temporary drug-related side effects.

Antibiotic resistant bacteria: current situation and treatment options to accelerate the development of a new antimicrobial arsenal

INTRODUCTION

Antibiotic resistance is one of the biggest public health threats worldwide. Currently, antibiotic-resistant bacteria kill 700,000 people every year. These data represent the near future in which we find ourselves, a "post-antibiotic era" where the identification and development of new treatments are key. This review is focused on the current and emerging antimicrobial therapies which can solve this global threat.

AREAS COVERED

Through a literature search using databases such as Medline and Web of Science, and search engines such as Google Scholar, different antimicrobial therapies were analyzed, including pathogen-oriented therapy, phagotherapy, microbiota and antivirulent therapy. Additionally, the development pathways of new antibiotics were described, emphasizing on the potential advantages that the combination of a drug repurposing strategy with the application of mathematical prediction models could bring to solve the problem of AMRs.

EXPERT OPINION

This review offers several starting points to solve a single problem: reducing the number of AMR. The data suggest that the strategies described could provide many benefits to improve antimicrobial treatments. However, the development of new antimicrobials remains necessary. Drug repurposing, with the application of mathematical prediction models, is considered to be of interest due to its rapid and effective potential to increase the current therapeutic arsenal.

In vitro activity of ceftazidime-avibactam against Gram-negative strains in patients with complicated urinary tract infection and complicated intra-abdominal infection in Colombia 2014-2018

Ceftazidime/avibactam (CAZ/AVI) has excellent in vitro activity against enterobacterales and Pseudomonas aeruginosa. The study aimed to analyze the in vitro antimicrobial activity of CAZ/AVI and other antibiotics against isolates of enterobacterales and P. aeruginosa from patients with complicated urinary tract infection (cUTI) and complicated intra-abdominal infection (cIAI) in Colombian hospitals between 2014 and 2018, using the Antimicrobial Testing Leadership and Surveillance (ATLAS) database. Enterobacterales and P. aeruginosa samples were obtained from patients with cUTI and cIAI. Susceptibility was determined using The Clinical and Laboratory Standards Institute (CLSI) breakpoints. Meropenem-non-susceptible isolates were screened for extended-spectrum β-lactamase (ESBL) production. Isolates that were positive for ESBL activity were examined by Multiplex Polymerase Chain Reaction (Multiplex PCR) to detect genotypic resistance. A total of 565 Enterobacterales and 95 P. aeruginosa from patients with cUTI and 345 Enterobacterales and 65 P. aeruginosa from patients with cIAI were isolated. In vitro activity showed susceptibility to CAZ/AVI greater than 99% for Enterobacterales and in lower percentages for P. aeruginosa in cUTI (78.46%) and cIAI (83.33%). CAZ/AVI showed good in vitro activity against multidrug-resistant (MDR) Enterobacterales and P. aeruginosa in patients with cUTI and cIAI.

Off-Label Use of Ceftazidime-Avibactam in a Premature Infant With Multidrug-Resistant Klebsiella pneumoniae Infection: A Case Report

PURPOSE

The emergence of multidrug-resistant (MDR) Gram-negative bacterial infections in the neonatal intensive care unit (NICU) is a major public health threat. Ceftazidime-avibactam (CAZ-AVI) provides a new option for treating infections caused by most beta-lactamase- and carbapenemase-producing Gram-negative bacteria in infants older than three months. However, treatment options are extremely limited, with no safety data available for preterm neonates. Here, we describe our experience regarding the safety and efficacy of off-label use of CAZ-AVI in a NICU in Brazil.

SUMMARY

We report a case of a premature infant (born at 29 weeks gestational age) treated with CAZ-AVI due to a bloodstream infection caused by MDR Klebsiella pneumoniae.

CONCLUSION

Treatment with CAZ-AVI was safe and effective in our patient.

Population Pharmacokinetic Modeling and Probability of Pharmacodynamic Target Attainment for Ceftazidime-Avibactam in Pediatric Patients Aged 3 Months and Older

Increasing prevalence of infections caused by antimicrobial-resistant gram-negative bacteria represents a global health crisis, and while several novel therapies that target various aspects of antimicrobial resistance have been introduced in recent years, few are currently approved for children. Ceftazidime-avibactam is a novel β-lactam β-lactamase inhibitor combination approved for adults and children 3 months and older with complicated intra-abdominal infection, and complicated urinary tract infection or hospital-acquired ventilator-associated pneumonia (adults only in the United States) caused by susceptible gram-negative bacteria. Extensive population pharmacokinetic (PK) data sets for ceftazidime and avibactam obtained during the adult clinical development program were used to iteratively select, modify, and validate the approved adult dosage regimen (2,000-500 mg by 2-hour intravenous (IV) infusion every 8 hours (q8h), with adjustments for renal function). Following the completion of one phase I (NCT01893346) and two phase II ceftazidime-avibactam studies (NCT02475733 and NCT02497781) in children, adult PK data sets were updated with pediatric PK data. This paper describes the development of updated combined adult and pediatric population PK models and their application in characterizing the population PK of ceftazidime and avibactam in children, and in dose selection for further pediatric evaluation. The updated models supported the approval of ceftazidime-avibactam pediatric dosage regimens (all by 2-hour IV infusion) of 50-12.5 mg/kg (maximum 2,000-500 mg) q8h for those ≥6 months to 18 years old, and 40-10 mg/kg q8h for those ≥3 to 6 months old with creatinine clearance > 50 mL/min/1.73 m2 .

Intravenous Ceftazidime-Avibactam in Extremely Premature Neonates With Carbapenem-Resistant Enterobacteriaceae: Two Case Reports

The increasing use of carbapenems has contributed to a notable distribution of carbapenem-resistant Enterobacteriaceae (CRE). Recently, the incidence of CRE-associated infections is increasing significantly in NICUs, which pose a grave challenge to clinical treatment. We report 2 cases of IV ceftazidimeavibactam use to treat CRE infections in extremely premature neonates. The first case was diagnosed with bacteraemia and meningitis and the second one was diagnosed with bacteraemia only. Due to the lack of neonatal-specific information for IV ceftazidime-avibactam, the usual pediatric dose (62.5 mg/kg/dose every 8 hours) was used in these patients. Clinical cure occurred in these 2 patients. Although blood cultures became sterile after starting ceftazidime-avibactam in the second case, the patient died, presumably owing to sepsis or various causes, such as prematurity and chronic lung disease. Large and randomized studies are necessary to ensure the safety and efficacy of IV ceftazidime-avibactam for the treatment of neonates with sepsis caused by multidrug resistant organisms.

Neonatal multidrug-resistant gram-negative infection: epidemiology, mechanisms of resistance, and management

Infants admitted to the neonatal intensive care unit, particularly those born preterm, are at high risk for infection due to the combination of an immature immune system, prolonged hospitalization, and frequent use of invasive devices. Emerging evidence suggests that multidrug-resistant gram-negative (MDR-GN) infections are increasing in neonatal settings, which directly threatens recent and ongoing advances in contemporary neonatal care. A rising prevalence of antibiotic resistance among common neonatal pathogens compounds the challenge of optimal management of suspected and confirmed neonatal infection. We review the epidemiology of MDR-GN infections in neonates in the United States and internationally, with a focus on extended-spectrum β-lactamase (ESBL)-producing Enterobacterales and carbapenem-resistant Enterobacterales (CRE). We include published single-center studies, neonatal collaborative reports, and national surveillance data. Risk factors for and mechanisms of resistance are discussed. In addition, we discuss current recommendations for empiric antibiotic therapy for suspected infections, as well as definitive treatment options for key MDR organisms. Finally, we review best practices for prevention and identify current knowledge gaps and areas for future research. IMPACT: Surveillance and prevention of MDR-GN infections is a pediatric research priority. A rising prevalence of MDR-GN neonatal infections, specifically ESBL-producing Enterobacterales and CRE, compounds the challenge of optimal management of suspected and confirmed neonatal infection. Future studies are needed to understand the impacts of MDR-GN infection on neonatal morbidity and mortality, and studies of current and novel antibiotic therapies should include a focus on the pharmacokinetics of such agents among neonates.

Antimicrobial Activity of Ceftazidime-Avibactam Against Contemporary Pathogens From Urinary Tract Infections and Intra-abdominal Infections Collected From US Children During the 2016-2019 INFORM Surveillance Program

BACKGROUND

Antibacterial activity of ceftazidime-avibactam (CAZ-AVI) was evaluated against bacterial isolates from children in the United States with a urinary tract infection (UTI) or intra-abdominal infection (IAI) during the 2016-2019 International Network for Optimal Resistance Monitoring program. Prevalence of isolates and susceptibility to CAZ-AVI in pediatric and adult patients were compared.

METHODS

Bacterial isolates were collected from children with a UTI or IAI at 70 US medical centers from 2016 to 2019. The antimicrobial activity of CAZ-AVI and comparator agents was tested by broth microdilution methods.

RESULTS

The most prevalent Enterobacterales pathogens in children with UTIs were Escherichia coli (62.5%), Klebsiella pneumoniae (12.1%) and Proteus mirabilis (6.2%). Minimum inhibitory concentration 90% values for CAZ-AVI against Enterobacterales (0.25 μg/mL) and Pseudomonas aeruginosa (4 μg/mL) were identical for children and adults. The most prevalent Enterobacterales pathogens in children with IAIs were E. coli (57.4%), K. pneumoniae (11.1%) and Enterobacter cloacae species complex (9.3%). All isolates of Enterobacterales from pediatric patients with UTI and IAI were susceptible to CAZ-AVI, including extended-spectrum β-lactamase phenotypes. Susceptibility of P. aeruginosa isolates to CAZ-AVI was 96.2% in children and 98.4% in adults with a UTI: for IAI it was 100% and 97.2%, respectively.

CONCLUSIONS

Contemporary UTI and IAI pathogens collected from US children from 2016 to 2019 exhibited similar prevalence and susceptibilities as isolates collected from adult patients. CAZ-AVI exhibited potent activity against these pathogens.

Evaluating the clinical effectiveness of new beta-lactam/beta-lactamase inhibitor combination antibiotics: A systematic literature review and meta-analysis

Background:

Ceftazidime/avibactam (C/A), ceftolozane/tazobactam (C/T), imipenem/relebactam (I/R), and meropenem/vaborbactam (M/V) combine either a cephalosporin (C/T and C/A) or a carbapenem antibiotic (M/V and I/R) with a β-lactamase inhibitor. They are used to treat carbapenem-resistant Enterobacterales (CRE) and/or multidrug-resistant Pseudomonas aeruginosa (MDRPA).

Objective:

We compared the pooled clinical success of these medications to older therapies.

Methods:

PubMed and EMBASE were searched from January 1, 2012, through September 2, 2020, for C/A, C/T, I/R, and M/V studies. The main outcome was clinical success, which was assessed using random-effects models. Stratified analyses were conducted for study drug, sample size, quality, infection source, study design, and multidrug-resistant gram-negative organism (MDRGNO) population. Microbiological success and 28- and 30-day mortality were assessed as secondary outcomes. Heterogeneity was determined using I2 values.

Results:

Overall, 25 articles met the inclusion criteria; 8 observational studies and 17 randomized control trials. We detected no difference in clinical success comparing new combination antibiotics with standard therapies for all included organisms (pooled OR, 1.21; 95% CI, 0.96–1.51). We detected a moderate level of heterogeneity among the included studies I2 = 56%. Studies that focused on patients with CRE or MDRPA infections demonstrated a strong association between treatment with new combination antibiotics and clinical success (pooled OR, 2.20; 95% CI, 1.60–3.57).

Conclusions:

C/T, C/A, I/R, and M/V are not inferior to standard therapies for treating various complicated infections, but they may have greater clinical success for treating MDRPA and CRE infections. More studies that evaluate the use of these antibiotics for drug-resistant infections are needed to determine their effectiveness.

New β-Lactam-β-Lactamase Inhibitor Combinations

The limited armamentarium against drug-resistant Gram-negative bacilli has led to the development of several novel β-lactam-β-lactamase inhibitor combinations (BLBLIs). In this review, we summarize their spectrum of in vitro activities, mechanisms of resistance, and pharmacokinetic-pharmacodynamic (PK-PD) characteristics. A summary of available clinical data is provided per drug. Four approved BLBLIs are discussed in detail. All are options for treating multidrug-resistant (MDR) Enterobacterales and Pseudomonas aeruginosa Ceftazidime-avibactam is a potential drug for treating Enterobacterales producing extended-spectrum β-lactamase (ESBL), Klebsiella pneumoniae carbapenemase (KPC), AmpC, and some class D β-lactamases (OXA-48) in addition to carbapenem-resistant Pseudomonas aeruginosa Ceftolozane-tazobactam is a treatment option mainly for carbapenem-resistant P. aeruginosa (non-carbapenemase producing), with some activity against ESBL-producing Enterobacterales Meropenem-vaborbactam has emerged as treatment option for Enterobacterales producing ESBL, KPC, or AmpC, with similar activity as meropenem against P. aeruginosa Imipenem-relebactam has documented activity against Enterobacterales producing ESBL, KPC, and AmpC, with the combination having some additional activity against P. aeruginosa relative to imipenem. None of these drugs present in vitro activity against Enterobacterales or P. aeruginosa producing metallo-β-lactamase (MBL) or against carbapenemase-producing Acinetobacter baumannii Clinical data regarding the use of these drugs to treat MDR bacteria are limited and rely mostly on nonrandomized studies. An overview on eight BLBLIs in development is also provided. These drugs provide various levels of in vitro coverage of carbapenem-resistant Enterobacterales, with several drugs presenting in vitro activity against MBLs (cefepime-zidebactam, aztreonam-avibactam, meropenem-nacubactam, and cefepime-taniborbactam). Among these drugs, some also present in vitro activity against carbapenem-resistant P. aeruginosa (cefepime-zidebactam and cefepime-taniborbactam) and A. baumannii (cefepime-zidebactam and sulbactam-durlobactam).

Novel Beta-Lactam/Beta-Lactamase Plus Metronidazole vs Carbapenem for Complicated Intra-abdominal Infections: A Meta-analysis of Randomized Controlled Trials

Background

Complicated intra-abdominal infections (cIAIs) remain a leading cause of death in surgical wards, in which antibiotic treatment is crucial. We aimed to compare the efficacy and safety of novel β-lactam/β-lactamase inhibitors (BL/BLIs) in combination with metronidazole and carbapenems in the treatment of cIAIs.

Methods

A comprehensive search of randomized controlled trials (RCTs) was performed using Medline, Embase, and Cochrane Library, which compared the efficacy and safety of novel BL/BLIs and carbapenems for the treatment of cIAIs.

Results

Six RCTs consisting of 2254 patients were included. The meta-analysis showed that novel BL/BLIs in combination with metronidazole had a lower clinical success rate (risk difference [RD], -0.05; 95% CI, -0.07 to -0.02; I ² = 0%) and a lower microbiological success rate (RD, -0.04; 95% CI, -0.08 to -0.00; I ² = 0%). No difference was found between the 2 groups in incidence of adverse events (RD, 0.02; 95% CI, -0.01 to 0.06; I ² = 0%), serious adverse events (SAEs; RD, 0.01; 95% CI, -0.02 to 0.03; I ² = 0%), or mortality (RD, 0.01; 95% CI, -0.00 to 0.02). However, ceftazidime/avibactam had a higher risk of vomiting (RD, 0.03; 95% CI, 0.01 to 0.05; I ² = 47%), and the ceftolozane/tazobactam subgroup showed a higher incidence of SAEs (RD, 0.12; 95% CI, 0.01 to 0.03).

Conclusions

The efficacy of novel BL/BLIs in combination with metronidazole was not as high as that of carbapenems. Although no significant differences were found with respect to overall adverse events, SAEs, or mortality, the novel BL/BLIs has a higher risk of vomiting. We still need to be cautious about the clinical application of a new anti-infective combination.

Trial registration

PROSPERO ID: 42020166061.

Resistance to Novel β-Lactam-β-Lactamase Inhibitor Combinations: The "Price of Progress"

Significant advances were made in antibiotic development during the past 5 years. Novel agents were added to the arsenal that target critical priority pathogens, including multidrug-resistant Pseudomonas aeruginosa and carbapenem-resistant Enterobacterales. Of these, 4 novel β-lactam-β-lactamase inhibitor combinations (ceftolozane-tazobactam, ceftazidime-avibactam, meropenem-vaborbactam, and imipenem-cilastatin-relebactam) reached clinical approval in the United States. With these additions comes a significant responsibility to reduce the possibility of emergence of resistance. Reports in the rise of resistance toward ceftolozane-tazobactam and ceftazidime-avibactam are alarming. Clinicians and scientists must make every attempt to reverse or halt these setbacks.

The Strategies of Pathogen-Oriented Therapy on Circumventing Antimicrobial Resistance

The emerging antimicrobial resistance (AMR) poses serious threats to the global public health. Conventional antibiotics have been eclipsed in combating with drug-resistant bacteria. Moreover, the developing and deploying of novel antimicrobial drugs have trudged, as few new antibiotics are being developed over time and even fewer of them can hit the market. Alternative therapeutic strategies to resolve the AMR crisis are urgently required. Pathogen-oriented therapy (POT) springs up as a promising approach in circumventing antibiotic resistance. The tactic underling POT is applying antibacterial compounds or materials directly to infected regions to treat specific bacteria species or strains with goals of improving the drug efficacy and reducing nontargeting and the development of drug resistance. This review exemplifies recent trends in the development of POTs for circumventing AMR, including the adoption of antibiotic-antibiotic conjugates, antimicrobial peptides, therapeutic monoclonal antibodies, nanotechnologies, CRISPR-Cas systems, and microbiota modulations. Employing these alternative approaches alone or in combination shows promising advantages for addressing the growing clinical embarrassment of antibiotics in fighting drug-resistant bacteria.

Optimal Management of Complicated Infections in the Pediatric Patient: The Role and Utility of Ceftazidime/Avibactam

Antimicrobial resistance poses a substantial threat to global public health. The pursuit of new antibiotics has decreased and very few options have been investigated for the treatment of complicated multidrug-resistant Gram-negative (MDR-GN) infections in adult population and even less in pediatric patients. Ceftazidime-avibactam (CAZ-AVI) is novel cephalosporin/β-lactamase inhibitor (BL-BLI) combination with broad antibacterial spectrum. The aim of this review is to describe the current and future role CAZ-AVI in the pediatric population with suspected or confirmed MDR-GN infections.

Treatment of Carbapenem-Resistant Enterobacteriaceae Infections in Children

Infections due to carbapenem-resistant Enterobacteriaceae (CRE) are increasingly prevalent in children and are associated with poor clinical outcomes. Optimal treatment strategies for CRE infections continue to evolve. A lack of pediatric-specific comparative effectiveness data, uncertain pediatric dosing regimens for several agents, and a relative lack of new antibiotics with pediatric indications approved by the US Food and Drug Administration (FDA) collectively present unique challenges for children. In this review, we provide a framework for antibiotic treatment of CRE infections in children, highlighting relevant microbiologic considerations and summarizing available data related to the evaluation of FDA-approved antibiotics (as of September 2019) with CRE activity, including carbapenems, ceftazidime-avibactam, meropenem-vaborbactam, imipenem/cilastatin-relebactam, polymyxins, tigecycline, eravacycline, and plazomicin.

Carbapenem-Resistant Gram-Negative Bacterial Infections in Children

Carbapenem-resistant organisms (CRO) are a major global public health threat. Enterobacterales hydrolyze almost all β-lactams through carbapenemase production. Infections caused by CRO are challenging to treat due to the limited number of antimicrobial options. This leads to significant morbidity and mortality. Over the last few years, several new antibiotics effective against CRO have been approved. Some of them (e.g., plazomicin or imipenem-cilastatin-relebactam) are currently approved for use only by adults; others (e.g., ceftazidime-avibactam) have recently been approved for use by children. Recommendations for antibiotic therapy of CRO infections in pediatric patients are based on evidence mainly from adult studies. The availability of pediatric pharmacokinetic and safety data is the cornerstone to broaden the use of proposed agents in adults to the pediatric population. This article provides a comprehensive review of the current knowledge regarding infections caused by CRO with a focus on children, which includes epidemiology, risk factors, outcomes, and antimicrobial therapy management, with particular attention being given to new antibiotics.