Effect of Meropenem-Vaborbactam vs Piperacillin-Tazobactam on Clinical Cure or Improvement and Microbial Eradication in Complicated Urinary Tract Infection: The TANGO I Randomized Clinical Trial

Review of Ceftazidime-Avibactam, Meropenem-Vaborbactam, and Imipenem/Cilastatin-Relebactam to Target Klebsiella pneumoniae Carbapenemase-Producing Enterobacterales

Objective: To provide a review of 3 novel antimicrobial agents-ceftazidime-avibactam, meropenem-vaborbactam, and imipenem/cilastatin-relebactam-regarding treatment of Klebsiella pneumoniae carbapenemase-producing Enterobacterales (KPC). Data Sources: A literature search of PubMed and OVID (MEDLINE) was performed up to March 2020 using the following search terms: Vabomere, meropenem-vaborbactam, vaborbactam, RPX7009, Klebsiella pneumoniae carbapenemase, KPC, carbapenem-resistant Enterobacteriaceae, CRE, relebactam, imipenem-relebactam, MK-7655, ceftazidime-avibactam. Abstracts from conferences, article bibliographies, and product information were also reviewed. Study Selection and Data Extraction: Articles were first screened by English language, then title, then abstract, and finally by review of the full article. Fifty-five clinical and preclinical studies were included. Data Synthesis: These 3 novel β-lactam/β-lactamase inhibitor combinations have shown considerable improvement in safety and efficacy as compared with traditional polymyxin-based combination therapy for the treatment of KPC infections. While meropenem-vaborbactam has not shown improved activity against Pseudomonas aeruginosa, it has shown decreased rates of resistance to KPC versus ceftazidime-avibactam. Conclusions: With increasing incidence of KPC infections on a global scale, pharmacists should be aware of the notable similarities and differences between these 3 agents, and the current data supporting their use. Pharmacists may want to consider meropenem-vaborbactam over ceftazidime-avibactam for KPC infections due to decreased likelihood of resistance.

The Epidemiology and Pathogenesis and Treatment of Pseudomonas aeruginosa Infections: An Update

Pseudomonas aeruginosa is a Gram-negative bacterial pathogen that is a common cause of nosocomial infections, particularly pneumonia, infection in immunocompromised hosts, and in those with structural lung disease such as cystic fibrosis. Epidemiological studies have identified increasing trends of antimicrobial resistance, including multi-drug resistant (MDR) isolates in recent years. P. aeruginosa has several virulence mechanisms that increase its ability to cause severe infections, such as secreted toxins, quorum sensing and biofilm formation. Management of P. aeruginosa infections focuses on prevention when possible, obtaining cultures, and prompt initiation of antimicrobial therapy, occasionally with combination therapy depending on the clinical scenario to ensure activity against P. aeruginosa. Newer anti-pseudomonal antibiotics are available and are increasingly being used in the management of MDR P. aeruginosa.

Advances in novel antibiotics to treat multidrug-resistant gram-negative bacterial infections

Antimicrobial resistance is a growing threat to public health and an increasingly common problem for acute care physicians to confront. Several novel antibiotics have been approved in the past decade to combat these infections; however, physicians may be unfamiliar with how to appropriately utilize them. The purpose of this review is to evaluate novel antibiotics active against resistant gram-negative bacteria and highlight clinical information regarding their use in the acute care setting. This review focuses on novel antibiotics useful in the treatment of infections caused by resistant gram-negative organisms that may be seen in the acute care setting. These novel antibiotics include ceftolozane/tazobactam, ceftazidime/avibactam, meropenem/vaborbactam, imipenem/cilistatin/relebactam, cefiderocol, plazomicin, eravacycline, and omadacycline. Acute care physicians should be familiar with these novel antibiotics so they can utilize them appropriately.

Treatment of UTIs Due to Klebsiella pneumoniae Carbapenemase-Producers: How to Use New Antibiotic Drugs? A Narrative Review

Background: K. pneumoniae is one of the bacteria most frequently causing health care-associated urinary tract infections, and increasingly incriminating Klebsiella pneumoniae carbapenemase producers (KPCp). Most infections caused by KPCp are nosocomial and might cause serious issues, even leading to death in half of the reported cases. Our aim was to identify the best strategy, based on available scientific data, for the use of new antibiotic treatments to manage KPCp UTIs. Methods: this narrative review of the literature was performed according to the criteria of preferred reporting items for systematic review and meta-analyses statement (PRISMA) (2020). Results and Conclusions: KPCp-UTIs are a real challenge for physicians. While cefiderocol, meropenem-vaborbactam, ceftazidim-avibactam, and imipenem-relebactam represent a major step forward in the treatment of these UTIs, no guidelines are currently available, in view of choosing the most appropriate treatment, in each specific case.

Multicenter clinical evaluation of VITEK® 2 meropenem-vaborbactam for susceptibility testing of Enterobacterales and Pseudomonas aeruginosa

The carbapenem/beta-lactamase inhibitor (meropenem-vaborbactam; MEV) used to treat complicated urinary tract infections and pyelonephritis in adults was approved in 2017 by the U.S. Food and Drug Administration (FDA). We evaluated VITEK 2 MEV (bioMérieux, Durham, NC) compared to the reference broth microdilution (BMD) method. Of 449 Enterobacterales isolates analyzed per FDA/CLSI breakpoints, overall performance was 98.2% Essential Agreement (EA), 98.7% Category Agreement (CA), and 0% Very Major Errors (VME) or Major Errors (ME). For FDA intended for use 438 Enterobacterales isolates, performance was 98.2% EA, 98.6% CA, and 0% VME or ME. Evaluable EA was 81.0% but with only 42 on-scale evaluable results. Individual species demonstrated EA and CA rates ≥ 90% without any VME or ME. When evaluated using European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints, overall VITEK 2 MEV performance for Enterobacterales and Pseudomonas aeruginosa demonstrated 97.3% EA, 99.2% CA, 2.3% VME, and 0.6% ME (after error resolution: 97.3% EA, 99.4% CA, 2.2% VME, and 0.4% ME) compared to the reference BMD method. Performance for P. aeruginosa included 92.2% EA, 97.4% CA, 0% VME, and 3.0% ME (after error resolution: 92.2% EA, 98.7% CA, 0% VME, and 1.5% ME). Performance for Enterobacterales included 98.2% EA, 99.6% CA, 3.0% VME, and 0.2% ME. Evaluable EA was 80.6% but due to only 67 evaluable results. These findings support VITEK 2 MEV as an accurate automated system for MEV susceptibility testing of Enterobacterales and P. aeruginosa and could be an alternate solution to the manual labor intensive reference BMD method.

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

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

Antibiotics in the pipeline: a literature review (2017-2020)

Introduction

Antimicrobial resistance (AMR) is an emerging global threat. It increases mortality and morbidity and strains healthcare systems. Health care professionals can counter the rising AMR by promoting antibiotic stewardship and facilitating new drug development. Even with the economic and scientific challenges, it is reassuring that new agents continue to be developed.

Methods

This review addresses new antibiotics in the pipeline. We conducted a review of the literature including Medline, Clinicaltrials.org, and relevant pharmaceutical companies for approved and in pipeline antibiotics in phase 3 or new drug application (NDA).

Results

We found a number of new antibiotics and reviewed their current development status, mode of action, spectra of activity, and indications for which they have been approved. The included studies from phase 3 clinical trials were mainly utilized for the treatment of acute bacterial skin and skin structure infections, community-acquired bacterial pneumonia, and pneumonia acquired in the healthcare settings. The number of these agents is limited against high priority organisms. The identified antibiotics were based mainly on previously known molecules or pre-existing antimicrobial agents.

Conclusion

There are a limited number of antibiotics against high priority organisms such as multi-drug-resistant Pseudomonas aeruginosa, and carbapenem-resistant Enterobacteriaceae. New antimicrobial agents directed against the top priority organisms as classified by the World Health Organization are urgently needed.

Population Pharmacokinetics of Meropenem and Vaborbactam Based on Data from Noninfected Subjects and Infected Patients

Meropenem-vaborbactam is a broad-spectrum carbapenem-beta-lactamase inhibitor combination approved in the United States and Europe to treat patients with complicated urinary tract infections and in Europe for other serious bacterial infections, including hospital-acquired and ventilator-associated pneumonia. Population pharmacokinetic (PK) models were developed to characterize the time course of meropenem and vaborbactam using pooled data from two phase 1 and two phase 3 studies. Multicompartment disposition model structures with linear elimination processes were fit to the data using NONMEM 7.2. Since both drugs are cleared primarily by the kidneys, estimated glomerular filtration rate (eGFR) was evaluated as part of the base structural models. For both agents, a two-compartment model with zero-order input and first-order elimination best described the pharmacokinetic PK data, and a sigmoidal Hill-type equation best described the relationship between renal clearance and eGFR. For meropenem, the following significant covariate relationships were identified: clearance (CL) decreased with increasing age, CL was systematically different in subjects with end-stage renal disease, and all PK parameters increased with increasing weight. For vaborbactam, the following significant covariate relationships were identified: CL increased with increasing height, volume of the central compartment (Vc) increased with increasing body surface area, and CL, Vc, and volume of the peripheral compartment were systematically different between phase 1 noninfected subjects and phase 3 infected patients. Visual predictive checks demonstrated minimal bias, supporting the robustness of the final models. These models were useful for generating individual PK exposures for pharmacokinetic-pharmacodynamic (PK-PD) analyses for efficacy and Monte Carlo simulations to evaluate PK-PD target attainment.

Real-world, Multicenter Experience With Meropenem-Vaborbactam for Gram-Negative Bacterial Infections Including Carbapenem-Resistant Enterobacterales and Pseudomonas aeruginosa

BACKGROUND

We aimed to describe the clinical characteristics and outcomes of patients treated with meropenem-vaborbactam (MEV) for a variety of gram-negative infections (GNIs), primarily including carbapenem-resistant Enterobacterales (CRE).

METHODS

This is a real-world, multicenter, retrospective cohort within the United States between 2017 and 2020. Adult patients who received MEV for ≥72 hours were eligible for inclusion. The primary outcome was 30-day mortality. Classification and regression tree analysis (CART) was used to identify the time breakpoint (BP) that delineated the risk of negative clinical outcomes (NCOs) and was examined by multivariable logistic regression analysis (MLR).

RESULTS

Overall, 126 patients were evaluated from 13 medical centers in 10 states. The most common infection sources were respiratory tract (38.1%) and intra-abdominal (19.0%) origin, while the most common isolated pathogens were CRE (78.6%). Thirty-day mortality and recurrence occurred in 18.3% and 11.9%, respectively. Adverse events occurred in 4 patients: nephrotoxicity (n = 2), hepatoxicity (n = 1), and rash (n = 1). CART-BP between early and delayed treatment was 48 hours (P = .04). MEV initiation within 48 hours was independently associated with reduced NCO following analysis by MLR (adusted odds ratio, 0.277; 95% CI, 0.081-0.941).

CONCLUSIONS

Our results support current evidence establishing positive clinical and safety outcomes of MEV in GNIs, including CRE. We suggest that delaying appropriate therapy for CRE significantly increases the risk of NCOs.

Antibiotic Approvals in the Last Decade: Are We Keeping Up With Resistance?

OBJECTIVE

To review the spectrum of activity, efficacy, safety, and role in therapy of all antibiotics and related biologics approved by the Food and Drug Administration (FDA) in the last decade.

DATA SOURCES

A literature search was performed using PubMed and Google Scholar (2010 to end May 2021) with the search terms' name of the antibiotic or the biologic. Data were also obtained from the prescribing information, FDA, and ClinicalTrials.gov websites.

STUDY SELECTION

All relevant English-language, late phase clinical trials assessing the safety and efficacy of the identified drugs were included. Review articles and references of retrieved articles were evaluated for relevant data.

DATA SYNTHESIS

Antibiotic resistance is a public health crisis, and antibiotic development is imperative to outpace the ability of bacteria to develop resistance. Only 17 new systemic antibiotics and 1 related biologic have been approved by the FDA since 2010. Among these drugs, 14 were approved for common bacterial infections, 1 was approved for Clostridioides difficile infection (CDI), 1 was licensed to prevent CDI recurrence, and 2 were approved for drug-resistant tuberculosis. Very few antibiotics are in clinical development.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

The arrival of these new antibiotics was welcomed with great enthusiasm, particularly when they met previously unmet medical needs. Unfortunately, the majority of them represent modifications to existing chemical structures rather than new drug classes. Despite the availability of these antibiotics, managing patients with deep-seated infections and those with extensively resistant gram-negative organisms remains challenging.

CONCLUSIONS

The number of new antibiotics and their indications are not keeping up with resistance and the needs of the patients.

Assessment of Data Supporting the Efficacy of New Antibiotics for Treating Infections Caused by Multidrug-resistant Bacteria

BACKGROUND

Infections caused by multidrug-resistant (MDR) bacteria are a major public health threat. We aimed to assess the data supporting US Food and Drug Administration (FDA) approval of new agents aimed to treat MDR bacterial infections and the data provided by postmarketing studies.

METHODS

We identified all drugs with in vitro activity against MDR bacteria initially approved by the FDA between January 2010 and December 2018. Characteristics of trials supporting approval and regulatory pathways were collected from Drugs@FDA. Characteristics of postmarketing studies were extracted from drug labels and ClinicalTrials.gov entries effective 1 June 2019.

RESULTS

Initial approval of 11 newly approved antibiotics with anti-MDR activity was supported by 20 trials, all with noninferiority design. All initially approved indications were for common infections, mostly acute bacterial skin and skin-structure infections, regardless of causative microorganism. The proportion of MDR bacteria in most trials was low (<10% for gram-negative infections, <1% for gram-positive pneumonia). Most trials (90%) excluded immunocompromised and critically ill patients. Of 16 additional postmarketing randomized controlled trials identified through ClinicalTrials.gov, only 2 exclusively included infections caused by MDR bacteria, comprising 116 patients. No drug was granted accelerated approval, which would mandate postmarketing efficacy studies.

CONCLUSIONS

The approval of new drugs with potential clinical activity against MDR bacteria is supported by trials evaluating infections caused by non-MDR organisms, using noninferiority design and excluding the patients most likely to require these agents. Subsequent postmarketing efficacy data against these organisms are scarce. Healthcare professionals and regulators should demand more robust data to support clinical decision making.

Carbapenemase-producing Enterobacteriaceae in transplant patients

Carbapenemase-producing Enterobacteriaceae (CPE) are a serious public health concern and represent a major threat to immunocompromised hosts, including solid organ (SOT) and stem cell transplant (HSCT) recipients. Transplant patients are at particular risk of developing CPE colonization and/or infection due to their frequent exposure to prolonged courses of broad-spectrum antibiotics, altered immunocompetence and exposure to invasive procedures and immunosuppressive drugs. Gut colonization with CPE, in particular carbapenem-resistant Klebsiella pneumoniae, may occur before or after SOT in 2%-27% of patients and among 2%-9% of HSCT and has been associated with increased risk of developing CPE infections. In endemic areas, CPE infections occur in up to 18% of SOT, and HSCT patients can account for 5%-18% of all patients with CPE bacteraemia. Mortality rates up to 70% have been associated with CPE infections in both patient populations. The rapid initiation of an active therapy against CPE is advocated in these infections. Therapeutic options, however, are limited by the paucity of novel compounds that are currently available and by potential antibiotic-associated toxicities. Therefore, a multidisciplinary approach involving infection control and antimicrobial stewardship programmes still represents the mainstay for the management of CPE infections among transplant patients. The evidence for the use of prevention strategies such as CPE-targeted perioperative prophylaxis or gut decolonization is still scarce. Large, multicentre trials are required to better define prevention strategies and to guide the management of CPE infections in the transplant setting.

Role of new antibiotics for KPC-producing Klebsiella pneumoniae

Klebsiella pneumoniae has accumulated a wide range of resistance determinants and has evolved into a difficult-to-treat pathogen that poses an increasing healthcare threat. KPC is an important marker for extensively drug-resistant (XDR) organisms with limited treatment options. In response to the medical need for new treatment options, several new antibiotics have been developed and registered recently. The β-lactamase inhibitor (BLI) combinations ceftazidime/avibactam, meropenem/vaborbactam and imipenem/relebactam, the cephalosporin-siderophore conjugate cefiderocol, the aminoglycoside derivative plazomicin and the tetracycline derivative eravacycline, focus on carbapenem-resistant Enterobacterales. These modified agents from old antibiotic classes illustrate the challenges of this requirement to address class-specific resistance mechanisms while critical gaps and some cross-resistance within a class, or to unrelated antibiotic classes, remain. The diverse molecular mechanisms and increasing diversification of carbapenem resistance among Klebsiella isolates requires improved rapid molecular diagnostic capabilities and stringent stewardship programmes to preserve the efficacy of new antibiotics for as long as possible.

Treatment for carbapenem-resistant Enterobacterales infections: recent advances and future directions

Carbapenem-resistant Enterobacterales (CRE) are a growing threat to human health worldwide. CRE often carry multiple resistance genes that limit treatment options and require longer durations of therapy, are more costly to treat, and necessitate therapies with increased toxicities when compared with carbapenem-susceptible strains. Here, we provide an overview of the mechanisms of resistance in CRE, the epidemiology of CRE infections worldwide, and available treatment options for CRE. We review recentlyapproved agents for the treatment of CRE, including ceftazidime-avibactam, meropenem-vaborbactam, imipenem-relebactam, cefiderocol, and novel aminoglycosides and tetracyclines. We also discuss recent advances in phage therapy and antibiotics that are currently in development targeted to CRE. The potential for the development of resistance to these therapies remains high, and enhanced antimicrobial stewardship is imperative both to reduce the spread of CRE worldwide and to ensure continued access to efficacious treatment options.

Lack of synergistic nephrotoxicity between vancomycin and piperacillin/tazobactam in a rat model and a confirmatory cellular model

BACKGROUND

Vancomycin and piperacillin/tazobactam are reported in clinical studies to increase acute kidney injury (AKI). However, no clinical study has demonstrated synergistic toxicity, only that serum creatinine increases.

OBJECTIVES

To clarify the potential for synergistic toxicity between vancomycin, piperacillin/tazobactam and vancomycin + piperacillin/tazobactam treatments by quantifying kidney injury in a translational rat model of AKI and using cell studies.

METHODS

(i) Male Sprague-Dawley rats (n = 32) received saline, vancomycin 150 mg/kg/day intravenously, piperacillin/tazobactam 1400 mg/kg/day intraperitoneally or vancomycin + piperacillin/tazobactam for 3 days. Urinary biomarkers and histopathology were analysed. (ii) Cellular injury was assessed in NRK-52E cells using alamarBlue®.

RESULTS

Urinary output increased from Day -1 to Day 1 with vancomycin but only after Day 2 for vancomycin + piperacillin/tazobactam-treated rats. Plasma creatinine was elevated from baseline with vancomycin by Day 2 and only by Day 4 for vancomycin + piperacillin/tazobactam. Urinary KIM-1 and clusterin were increased with vancomycin from Day 1 versus controls (P < 0.001) and only on Day 3 with vancomycin + piperacillin/tazobactam (P < 0.001, KIM-1; P < 0.05, clusterin). The histopathology injury score was elevated only in the vancomycin group when compared with piperacillin/tazobactam as a control (P = 0.04) and generally not so with vancomycin + piperacillin/tazobactam. In NRK-52E cells, vancomycin induced cell death with high doses (IC50 48.76 mg/mL) but piperacillin/tazobactam did not, and vancomycin + piperacillin/tazobactam was similar to vancomycin.

CONCLUSIONS

All groups treated with vancomycin demonstrated AKI; however, vancomycin + piperacillin/tazobactam was not worse than vancomycin. Histopathology suggested that piperacillin/tazobactam did not worsen vancomycin-induced AKI and may even be protective.

Choosing Optimal Antibiotics for the Treatment of Patients Infected With Enterobacteriaceae: A Network Meta-analysis and Cost-Effectiveness Analysis

Overuse of carbapenems has led to the increasing carbapenem-resistant Enterobacteriaceae. It is still unknown whether other antibiotics [especially novel β-lactam/β-lactamase inhibitor combinations (BL/BLIs)] are better than carbapenems in the treatment of Enterobacteriaceae. A systematic literature search was performed to identify randomized controlled trials (RCTs) assessing the efficacy and safety of any antibiotics on Enterobacteriaceae infections. We carried out a traditional paired meta-analysis to compare ceftazidime/avibactam to comparators. Network meta-analysis (NMA) was conducted to integrate direct and indirect evidence of all interventions. Moreover, cost-effectiveness analysis using a combined decision analytical Markov model was completed for the treatment of patients with complex urinary tract infection (cUTI). A total of 25 relevant RCTs were identified, comprising 15 different interventions. Ceftazidime/avibactam exhibited comparable efficacy and safety with comparators (carbapenems) in the paired meta-analysis. In the NMA, the surface under the cumulative ranking curve probabilities showed that in terms of efficacy, the interventions with the highest-ranking were meropenem/vaborbactam, meropenem, imipenem/cilastatin, ceftriaxone, ceftazidime/avibactam, and ceftolozane/tazobactam [but no significant difference between any two antibiotics (p > 0.05)]. Regarding safety, ceftazidime/avibactam had a higher incidence of adverse events than that of piperacillin/tazobactam (relative risk = 0.74, 95% confidence interval = 0.59–0.94). Based on drug and hospitalization costs in China, the incremental cost-effectiveness ratio per quality-adjusted life-year gained in the patients with cUTI for meropenem, ceftazidime/avibactam, and ceftolozane/tazobactam compared to imipenem/cilastatin were US$579, US$24569, and US$29040, respectively. The role of these BL/BLIs to serve as alternatives to carbapenems requires large-scale and high-quality studies to validate.

Emerging Treatment Options for Multi-Drug-Resistant Bacterial Infections

Antimicrobial resistance (AMR) remains one of the top public health issues of global concern. Among the most important strategies for AMR control there is the correct and appropriate use of antibiotics, including those available for the treatment of AMR pathogens. In this article, after briefly reviewing the most important and clinically relevant multi-drug-resistant bacteria and their main resistance mechanisms, we describe the emerging antimicrobial options for both MDR Gram-positive cocci and Gram-negative bacilli, including recently marketed agents, molecules just approved or under evaluation and rediscovered older antibiotics that have regained importance due to their antimicrobial spectrum. Specifically, emerging options for Gram-positive cocci we reviewed include ceftaroline, ceftobiprole, tedizolid, dalbavancin, and fosfomycin. Emerging treatment options for Gram-negative bacilli we considered comprise ceftolozane-tazobactam, ceftazidime-avibactam, meropenem-vaborbactam, imipenem-relebactam, aztreonam-avibactam, minocycline, fosfomycin, eravacycline, plazomicin, and cefiderocol. An exciting scenario is opening today with the long awaited growing availability of novel molecules for the treatment of AMR bacteria. Knowledge of mechanisms of action and resistance patterns allows physicians to increasingly drive antimicrobial treatment towards a precision medicine approach. Strict adherence to antimicrobial stewardship practices will allow us to preserve the emerging antimicrobials for our future.

Carbapenemase producing Klebsiella pneumoniae: implication on future therapeutic strategies

Introduction: The emergence of carbapenemase resistant Gram-negative is designated as an 'urgent' priority of public health. Carbapenemase producing Klebsiella pneumoniae (CPKP) is linked with significant mortality. Conventionally used antibiotics (polymyxins, tigecycline, aminoglycosides, etc.) are associated with poor efficacy and toxicity profiles are quite worrisome.Areas covered: This article reviews mechanism of resistance and evidence regarding novel treatments of infections caused by CPKP, focusing mainly on currently approved new therapies and implications on future therapeutic strategies. A review of novel β-lactam/β-lactamase inhibitors (BLI) recently approved and in clinical development as well as cefiderocol, eravacycline and apramycin are discussed.Expert opinion: Newly approved and forthcoming antimicrobial agents are promising to combat infections caused by CPKP. Ceftazidime-avibactam, meropenem-vaborbactam, and imipenem-cilastatin-relebactam are novel agents with favorable outcome and associated with improved mortality in KPC-producing K. pneumoniae infections. However, are inactive against metallo-β-lactamases (MBL). Novel BLI in later stage of development, i.e. aztreonam-avibactam, cefepime-zidebactam, cefepime-taniborbactam, and meropenem-nacubactam as well as cefiderocol are active in vitro against both KPC and MBL. Potential expectations of future therapeutic strategies are improved potency against CPKP, more tolerable safety profile, and capability of overcoming current resistance mechanism of multidrug-resistant K. pneumoniae.

Lefamulin efficacy and safety in a pooled phase 3 clinical trial population with community-acquired bacterial pneumonia and common clinical comorbidities

Background

Lefamulin, a first-in-class pleuromutilin antibiotic approved for intravenous and oral use in adults with community-acquired bacterial pneumonia (CABP), was noninferior to moxifloxacin in the Lefamulin Evaluation Against Pneumonia (LEAP) 1 intravenous-to-oral switch study and the LEAP 2 oral-only study. Using pooled LEAP 1/2 data, we examined lefamulin efficacy/safety overall and within subgroups of patients presenting with comorbidities typical in CABP management.

Methods

In LEAP 1, adults with CABP were randomized to receive intravenous lefamulin (150 mg every 12 h) for 5‒7 days or moxifloxacin (400 mg every 24 h) for 7 days, with optional intravenous-to-oral switch if predefined improvement criteria were met. In LEAP 2, adults with CABP were randomized to receive oral lefamulin (600 mg every 12 h) for 5 days or moxifloxacin (400 mg every 24 h) for 7 days. Both studies assessed early clinical response (ECR) at 96 ± 24 h after first study drug dose and investigator assessment of clinical response (IACR) at test-of-cure (5‒10 days after last dose). Pooled analyses of the overall population used a 10% noninferiority margin.

Results

Lefamulin (n = 646) was noninferior to moxifloxacin (n = 643) for ECR (89.3% vs 90.5%, respectively; difference  − 1.1%; 95% CI  − 4.4 to 2.2); IACR success rates at test-of-cure were similarly high (≥ 85.0%). High efficacy with both lefamulin and moxifloxacin was also demonstrated across all well-represented patient subgroups, including those with advanced age, diabetes mellitus, a history of cardiovascular diseases (e.g., hypertension, congestive heart failure, or arrhythmia) or chronic lung diseases (e.g., asthma or chronic obstructive pulmonary disease), elevated liver enzymes, or mild-to-moderate renal dysfunction. No new safety signals were identified.

Conclusions

Lefamulin may provide a valuable intravenous/oral monotherapy alternative to fluoroquinolones or macrolides for empiric treatment of patients with CABP, including cases of patients at risk for poor outcomes due to age or various comorbidities.

Trial registration

ClinicalTrials.gov LEAP 1 (NCT02559310; Registration Date: 24/09/2015) and LEAP 2 (NCT02813694; Registration Date: 27/06/2016).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01472-z.

Infectious Diseases Society of America Guidance on the Treatment of Extended-Spectrum β-lactamase Producing Enterobacterales (ESBL-E), Carbapenem-Resistant Enterobacterales (CRE), and Pseudomonas aeruginosa with Difficult-to-Treat Resistance (DTR-P. aeruginosa)

BACKGROUND

Antimicrobial-resistant infections are commonly encountered in US hospitals and result in significant morbidity and mortality. This guidance document provides recommendations for the treatment of infections caused by extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E), carbapenem-resistant Enterobacterales (CRE), and Pseudomonas aeruginosa with difficult-to-treat resistance (DTR-P. aeruginosa).

METHODS

A panel of 6 infectious diseases specialists with expertise in managing antimicrobial-resistant infections formulated common questions regarding the treatment of ESBL-E, CRE, and DTR-P. aeruginosa infections. Based on review of the published literature and clinical experience, the panel provide recommendations and associated rationale for each recommendation. Because of significant differences in the molecular epidemiology of resistance and the availability of specific anti-infective agents globally, this document focuses on treatment of antimicrobial-resistant infections in the United States.

RESULTS

Approaches to empiric treatment selection, duration of therapy, and other management considerations are briefly discussed. The majority of guidance focuses on preferred and alternative treatment recommendations for antimicrobial-resistant infections, assuming that the causative organism has been identified and antibiotic susceptibility testing results are known. Treatment recommendations apply to both adults and children.

CONCLUSIONS

The field of antimicrobial resistance is dynamic and rapidly evolving, and the treatment of antimicrobial-resistant infections will continue to challenge clinicians. This guidance document is current as of 17 September 2020. Updates to this guidance document will occur periodically as new data emerge. Furthermore, the panel will expand recommendations to include other problematic gram-negative pathogens in future versions. The most current version of the guidance including the date of publication can be found at www.idsociety.org/practice-guideline/amr-guidance/.

Early Experience With Meropenem-Vaborbactam for Treatment of Carbapenem-resistant Enterobacteriaceae Infections

Twenty patients with carbapenem-resistant Enterobacteriaceae infections were treated with meropenem-vaborbactam. Thirty-day clinical success and survival rates were 65% (13/20) and 90% (18/20), respectively. Thirty-five percent of patients had microbiologic failures within 90 days. One patient developed a recurrent infection due to meropenem-vaborbactam-nonsusceptible, ompK36 porin mutant Klebsiella pneumoniae.

A systematic review of antimicrobial susceptibility testing as a tool in clinical trials assessing antimicrobials against infections due to gram-negative pathogens

BACKGROUND

Antimicrobial susceptibility testing (AST) is the standard of care for treating bacterial infections. In randomized clinical trials of new antimicrobials, AST might not be performed or reported in real time.

OBJECTIVES

To determine local, real-time laboratory AST performance, its usage in the trial flow, quality control (QC) of the local testing, central AST performance and the effect of using AST categorization on the trials' primary outcomes.

DATA SOURCES

We systematically searched PubMed, Embase, PsychINFO and Web of Science.

ELIGIBILITY CRITERIA

We included registered randomized controlled trials published in journals between January 2015 and December 2019.

PARTICIPANTS AND INTERVENTIONS

We included trials comparing different antibiotics for the treatment of infections caused predominantly by Gram-negative bacteria.

METHODS

Primary outcomes for different trial populations were extracted and differences between trial arms were compared for patients with infections caused by susceptible versus non-susceptible bacteria. Results are described narratively.

RESULTS

Of 32 randomized trials, 25 trials reported that local AST was performed, 1312 reported the local laboratory AST methods, no trial reported QC, but post-hoc referral for AST at a reference laboratory was common. Patients' outcomes were superior when patients with infections due to susceptible and non-susceptible pathogens were compared post hoc (median difference 14%, interquartile range 8%-24%) in trials allowing this comparison (seven antimicrobials), except for colistin, where 14-day mortality was 9% higher when patients were treated with colistin for colistin-susceptible versus colistin-resistant carbapenem-resistant Acinetobacter baumannii. When excluding patients with pathogens that were non-susceptible to either antimicrobial in the trials, the difference in the primary outcome between the trial arms was reduced in five out of six trials.

CONCLUSIONS

Trials should perform AST to guide patient inclusion or exclusion from the study and consider the impact of the central laboratory susceptibility results on the study outcomes when using post-hoc reference testing.

Present and Future Perspectives on Therapeutic Options for Carbapenemase-Producing Enterobacterales Infections

Carbapenem-resistant Enterobacterales (CRE) are included in the list of the most threatening antibiotic resistance microorganisms, being responsible for often insurmountable therapeutic issues, especially in hospitalized patients and immunocompromised individuals and patients in intensive care units. The enzymatic resistance to carbapenems is encoded by different β-lactamases belonging to A, B or D Ambler class. Besides compromising the activity of last-resort antibiotics, CRE have spread from the clinical to the environmental sectors, in all geographic regions. The purpose of this review is to present present and future perspectives on CRE-associated infections treatment.

Nosocomial Pneumonia in the Era of Multidrug-Resistance: Updates in Diagnosis and Management

Nosocomial pneumonia (NP), including hospital-acquired pneumonia in non-intubated patients and ventilator-associated pneumonia, is one of the most frequent hospital-acquired infections, especially in the intensive care unit. NP has a significant impact on morbidity, mortality and health care costs, especially when the implicated pathogens are multidrug-resistant ones. This narrative review aims to critically review what is new in the field of NP, specifically, diagnosis and antibiotic treatment. Regarding novel imaging modalities, the current role of lung ultrasound and low radiation computed tomography are discussed, while regarding etiological diagnosis, recent developments in rapid microbiological confirmation, such as syndromic rapid multiplex Polymerase Chain Reaction panels are presented and compared with conventional cultures. Additionally, the volatile compounds/electronic nose, a promising diagnostic tool for the future is briefly presented. With respect to NP management, antibiotics approved for the indication of NP during the last decade are discussed, namely, ceftobiprole medocaril, telavancin, ceftolozane/tazobactam, ceftazidime/avibactam, and meropenem/vaborbactam.

An Update on Eight "New" Antibiotics against Multidrug-Resistant Gram-Negative Bacteria

Infections in the ICU are often caused by Gram-negative bacteria. When these microorganisms are resistant to third-generation cephalosporines (due to extended-spectrum (ESBL) or AmpC beta-lactamases) or to carbapenems (for example carbapenem producing Enterobacteriales (CPE)), the treatment options become limited. In the last six years, fortunately, there have been new antibiotics approved by the U.S. Food and Drug Administration (FDA) with predominant activities against Gram-negative bacteria. We aimed to review these antibiotics: plazomicin, eravacycline, temocillin, cefiderocol, ceftazidime/avibactam, ceftolozane/tazobactam, meropenem/vaborbactam, and imipenem/relebactam. Temocillin is an antibiotic that was only approved in Belgium and the UK several decades ago. We reviewed the in vitro activities of these new antibiotics, especially against ESBL and CPE microorganisms, potential side effects, and clinical studies in complicated urinary tract infections (cUTI), intra-abdominal infections (cIAI), and hospital-acquired pneumonia/ventilator-associatedpneumonia (HAP/VAP). All of these new antibiotics are active against ESBL, and almost all of them are active against CPE caused by KPC beta-lactamase, but only some of them are active against CPE due to MBL or OXA beta-lactamases. At present, all of these new antibiotics are approved by the U.S. Food and Drug Administration for cUTI (except eravacycline) and most of them for cIAI (eravacycline, ceftazidime/avibactam, ceftolozane/tazobactam, and imipenem/relebactam) and for HAP or VAP (cefiderocol, ceftazidime/avibactam, ceftolozane/tazobactam, and imipenem/relebactam).

Recent molecules in the treatment of severe infections caused by ESBL-producing bacteria

Introduction: The widespread increase in resistance to β-lactam antibiotics in Enterobacterales currently represents one of the main threats to human health worldwide. The primary mechanisms of resistance are the production of β-lactamase enzymes that are able to hydrolyze β-lactams.Areas covered: we summarize the most recent advances regarding the main characteristics and spectrum of activity of new available antibiotics and strategies for the treatment of ESBL-producing Enterobacterales infections.Expert opinion: ESBL-producing strains are recognized as a worldwide challenge in the treatment of both hospital- and community-acquired infections. Data from the literature point out the high mortality associated with severe infections due to ESBL strains, especially in patients who developed severe sepsis or septic shock, together with the importance of the source of infection and indicators of severity, as determinants of the patient's outcome. Carbapenems are currently considered the first-line therapy, although the diffusion of resistant strains is an evolving problem and is mandatory the introduction in clinical practice of new drug regimens and treatment strategies, based on clinical data, local epidemiology, and microbiology. As a possible carbapenem-sparing strategy, ceftolozane-tazobactam and ceftazidime-avibactam appear the best-available carbapenem-sparing therapies. The definitive role of new drugs should be definitively assessed.

Heterogeneity of Recent Phase 3 Complicated Urinary Tract Infection Clinical Trials

Background

For new antibiotics developed to treat antibiotic-resistant Gram-negative infections, the US Food and Drug Administration (FDA) regulatory pathway includes complicated urinary tract infection (cUTI) clinical trials in which the clinical isolates are susceptible to the active control. This allows for inferential testing in a noninferiority study design. Although complying with regulatory guidelines, individual clinical trials may differ substantially in design and patient population. To determine variables that impacted patient selection and outcome parameters, 6 recent cUTI trials that were pivotal to an new drug application (NDA) submission were reviewed.

Methods

This selective descriptive analysis utilized cUTI trial data, obtained from publicly disclosed information including FDA documents and peer-reviewed publications, from 6 new antibiotics developed to treat multidrug-resistant Gram-negative infections: ceftolozane-tazobactam, ceftazidime-avibactam, meropenem-vaborbactam, cefiderocol, plazomicin, and fosfomycin. Eravacycline was not approved for cUTI and is not included.

Results

Microbiologic modified intent-to-treat sample size, age, proportions of female patients, acute pyelonephritis (AP), Escherichia coli and other pathogens at baseline, protocol-specified switch to oral antibiotic, and the noninferiority margin were compared. Outcome data included clinical response, microbiologic eradication, and composite outcomes, including a subset of patients with AP.

Conclusions

A study design can follow regulatory guidelines but still have variable populations. The proportion of AP within a study varied greatly and influenced population demographics (age, gender) and baseline microbiology. A smaller proportion of AP resulted in an older patient population, fewer females, less E coli, and lower proportions of patients achieving success. Fluoroquinolones and piperacillin/tazobactam should be reconsidered as active comparators given the high rates of resistance to these antibiotics.

Meta-analysis of Clinical Outcomes Using Ceftazidime/Avibactam, Ceftolozane/Tazobactam, and Meropenem/Vaborbactam for the Treatment of Multidrug-Resistant Gram-Negative Infections

Ceftolozane-tazobactam (C/T), ceftazidime-avibactam (C/A), and meropenem/vaborbactam (M/V) are new beta-lactam/beta-lactamase combination antibiotics commonly used to treat multidrug-resistant Pseudomonas aeruginosa (MDRPA) and carbapenem-resistant Enterobacteriaceae (CRE) infections. This review reports the clinical success rates for C/T, C/A, and M/V. PubMed and EMBASE were searched from January 1, 2012, through September 2, 2020, for publications detailing the use of C/T, C/A, and M/V. A meta-analysis determined the pooled effectiveness of C/T, C/A, and M/V. The literature search returned 1950 publications; 29 publications representing 1620 patients were retained. Pneumonia was the predominant infection type (49.8%). MDRPA was the major pathogen treated (65.3%). The pooled clinical success rate was 73.3% (95% CI, 68.9%-77.5%). C/T, C/A, or M/V resistance was reported in 8.9% of the population. These antibiotics had a high clinical success rate in patients with complicated infections and limited treatment options. Larger studies comparing C/T, C/A, and M/V against other antibiotic regimens are needed.

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.

Spontaneous bacterial peritonitis due to carbapenemase-producing Enterobacteriaceae: Etiology and antibiotic treatment

Carbapenem antibiotics were first introduced in the 1980s and have long been considered the most active agents for the treatment of multidrug-resistant gram-negative bacteria. Over the last decade, carbapenem-resistant Enterobacteriaceae (CRE) have emerged as organisms causing spontaneous bacterial peritonitis. Infections caused by CRE have shown a higher mortality rate than those caused by bacteria sensitive to carbapenem antibiotics. Current antibiotic guidelines for the treatment of spontaneous bacterial peritonitis are insufficient, and rapid de-escalation of empiric antibiotic treatment is not widely recognized. This review summarizes the molecular characteristics, epidemiology and possible treatment of spontaneous bacterial peritonitis caused by CRE.

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).

New Carbapenemase Inhibitors: Clearing the Way for the β-Lactams

Carbapenem resistance is a major global health problem that seriously compromises the treatment of infections caused by nosocomial pathogens. Resistance to carbapenems mainly occurs via the production of carbapenemases, such as VIM, IMP, NDM, KPC and OXA, among others. Preclinical and clinical trials are currently underway to test a new generation of promising inhibitors, together with the recently approved avibactam, relebactam and vaborbactam. This review summarizes the main, most promising carbapenemase inhibitors synthesized to date, as well as their spectrum of activity and current stage of development. We particularly focus on β-lactam/β-lactamase inhibitor combinations that could potentially be used to treat infections caused by carbapenemase-producer pathogens of critical priority. The emergence of these new combinations represents a step forward in the fight against antimicrobial resistance, especially in regard to metallo-β-lactamases and carbapenem-hydrolysing class D β-lactamases, not currently inhibited by any clinically approved inhibitor.

A Critical Evaluation of Newer β-Lactam Antibiotics for Treatment of Pseudomonas aeruginosa Infections

OBJECTIVE

This article critically evaluates common Pseudomonas aeruginosa resistance mechanisms and the properties newer β-lactam antimicrobials possess to evade these mechanisms.

DATA SOURCES

An extensive PubMed, Google Scholar, and ClinicalTrials.gov search was conducted (January 1995 to July 2020) to identify relevant literature on epidemiology, resistance mechanisms, antipseudomonal agents, newer β-lactam agents, and clinical data available pertaining to P aeruginosa.

STUDY SELECTION AND DATA EXTRACTION

Relevant published articles and package inserts were reviewed for inclusion.

DATA SYNTHESIS

Therapeutic options to treat P aeruginosa infections are limited because of its intrinsic and acquired resistance mechanisms. The goal was to identify advances with newer β-lactams and characterize improvements in therapeutic potential for P aeruginosa infections.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Multidrug-resistant (MDR) P aeruginosa isolates are increasingly encountered from a variety of infections. This review highlights potential activity gains of newer β-lactam antibacterial drugs and the current clinical data to support their use. Pharmacists will be asked to recommend or evaluate the use of these agents and need to be aware of information specific to P aeruginosa, which differs from experience derived from Enterobacterales infections.

CONCLUSIONS

Newer agents, including ceftazidime-avibactam, ceftolozane-tazobactam, imipenem-relebactam, and cefiderocol, are useful for the treatment of MDR P aeruginosa infections. These agents offer improved efficacy and less toxicity compared with aminoglycosides and polymyxins and can be used for pathogens that are resistant to first-line antipseudomonal β-lactams. Selection of one agent over another should consider availability, turnaround of susceptibility testing, and product cost. Efficacy data specific for pseudomonal infections are limited, and there are no direct comparisons between the newer agents.

The safety and efficacy of relebactam/imipenem/cilastatin in Japanese patients with complicated intra-abdominal infection or complicated urinary tract infection: A multicenter, open-label, noncomparative phase 3 study

INTRODUCTION

Relebactam, a novel class A/C β-lactamase inhibitor developed as a fixed-dose combination with imipenem/cilastatin, restores imipenem activity against imipenem-nonsusceptible gram-negative pathogens.

METHODS

This phase 3, multicenter, open-label, noncomparative study (NCT03293485) evaluated relebactam/imipenem/cilastatin (250 mg/500 mg/500 mg) dosed every 6 h for 5-14 days in Japanese patients with complicated intra-abdominal infections (cIAIs) or complicated urinary tract infections (cUTIs), including those with secondary sepsis. Sepsis was defined as an infection-induced systemic inflammatory response syndrome, with a documented positive blood culture; patients meeting these protocol-defined criteria were evaluated for efficacy against sepsis.

RESULTS

Of 83 patients enrolled, 81 patients (cIAI, n = 37; cUTI, n = 44) received ≥1 dose of study treatment. Escherichia coli was the most common baseline pathogen isolated in both patients with cIAI and cUTI. Adverse events (AEs) were reported in 74.1% (n = 60/81) of patients, and drug-related AEs occurred in 18.5% (n = 15/81). The most common AEs were diarrhea and nausea (8.6%). Serious AEs occurred in nine patients, including one death, but none were considered treatment related. The primary efficacy endpoint for patients with cIAI was clinical response at end of treatment (EOT) in the microbiologically evaluable (ME) population, and for patients with cUTI was microbiological response at EOT in the ME population. The proportion of cIAI and cUTI patients achieving favorable responses were 85.7% (n = 24/28) and 100.0% (n = 39/39), respectively. All patients with sepsis (cIAI, n = 1; cUTI, n = 5) achieved a favorable composite clinical and microbiological response at EOT.

CONCLUSIONS

A favorable safety and efficacy profile for relebactam/imipenem/cilastatin was observed in Japanese patients with cIAI and cUTI.

[New antibiotics for severe infections due to multidrug-resistant pathogens : Definitive treatment and escalation]

Multidrug-resistant pathogens often lead to treatment failure of antimicrobial regimens. After a period of imbalance between the occurrence/spread of resistance mechanisms and the development of new substances, some new substances have meanwhile been approved and many more are currently undergoing clinical testing. They are particularly effective against specific resistance mechanisms/pathogens and should be preserved for definitive treatment of an isolated pathogen. In the absence of alternatives reserve antibiotics, such as aztreonam and colistin have experienced a renaissance. They are again used in special infection scenarios and clinically tested in combination with new substances. Despite the introduction and development of new substances the building of resistance will at some time also render these (at least partially) ineffective. Therefore, their implementation must be carried out according to the antibiotic or infectious diseases stewardship.

An evaluation of meropenem/vaborbactam for the treatment of nosocomial pneumonia

Introduction: Nosocomial pneumonias are the second most common healthcare-associated infections (HCAIs), often associated with the presence of Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Acinetobacter species, and Enterobacter species. Increasing use of carbapenems has led to an increase in the prevalence of carbapenem-resistant gram-negative organisms, such as carbapenem-resistant Enterobacterales (CRE), P. aeruginosa (CRPA), and Acinetobacter baumannii (CRAB), limiting treatment options for patients at high-risk of multi-drug resistant (MDR) gram-negative pathogens. Areas covered: The purpose of this review is to discuss the role of meropenem/vaborbactam, a beta-lactam combined with a novel non-beta-lactam cyclic boronic acid beta-lactamase inhibitor (BLI), for the treatment of nosocomial pneumonia based on its chemistry, pharmacokinetics/dynamics, microbiological spectrum of activity, mechanisms of resistance, safety, and clinical efficacy. Expert opinion: Currently, any utilization of meropenem/vaborbactam beyond its FDA-approved indication for complicated urinary tract infections is considered off-label use; however, based on the pulmonary penetration of meropenem/vaborbactam, it is highly likely to be a safe and effective alternative to more toxic agents, like aminoglycosides and polymixins, for targeted therapy in pulmonary infections due to CRE. Unfortunately, the multifactorial resistance pattern of CRPA and other non-lactose-fermenting gram-negative bacteria restricts activity against these organisms which are common pathogens implicated in nosocomial pneumonia.

An Appraisal of the Pharmacokinetic and Pharmacodynamic Properties of Meropenem-Vaborbactam

Carbapenem-resistant gram-negative pathogens remain an urgent public health threat, and safe, effective treatment options are limited. Although several agents are now available to combat these infections, meropenem-vaborbactam was the first to combine a novel, cyclic, boronic acid-based, β-lactamase inhibitor with a carbapenem backbone. Vaborbactam emanated from a discovery program specifically designed to identify candidate β-lactamase inhibitors with biochemical, microbiologic, and pharmacologic properties optimized for use in conjunction with a carbapenem. Meropenem was selected as the ideal carbapenem given its broad-spectrum in vitro activity, well established safety profile, and proven efficacy in the treatment of serious gram-negative infections. The combination has demonstrated potent in vitro activity against resistant gram-negative pathogens, particularly KPC-producing Klebsiella pneumoniae (MIC₅₀ values typically ≤ 0.06 mg/l). Importantly, the pharmacokinetic (PK) profiles of the two agents are well matched, and the approved optimized dosing regimen of 4 g every 8 h (Q8h) as a 3-h infusion provides reliable probability of target attainment against the majority of commonly encountered carbapenem-resistant Enterobacteriaceae (CRE). Robust in vitro and in vivo PK/pharmacodynamic (PD) data support the ability of this dosing regimen to achieve specified PK/PD targets for both bactericidal activity and prevention of resistance among pathogens with MICs up to 8 mg/l. This concerted effort into optimizing the PK and PD parameters of both the β-lactam and β-lactamase inhibitor alone and in combination contributed to the clinical success of meropenem-vaborbactam demonstrated in phase 3 trials in patients with complicated urinary tract infections (cUTI), including acute pyelonephritis (AP), and serious CRE infections. As the use of meropenem-vaborbactam increases concomitantly with the prevalence of KPC-producing CRE, continued pharmacovigilance and antimicrobial stewardship efforts will be of upmost importance to ensure that these PK/PD efforts translate into improved patient outcomes.

Treating infections caused by carbapenemase-producing Enterobacterales (CPE): a pragmatic approach to antimicrobial stewardship on behalf of the UKCPA Pharmacy Infection Network (PIN)

The emergence of carbapenemase-producing Enterobacterales (CPE) as a major cause of invasive infection both within the UK and internationally poses a very real concern for all providers of healthcare. The burden of morbidity and mortality associated with CPE infections is well described. The need for early, targeted, effective and safe antimicrobial therapy remains key for the management of these infected patients yet reliable antimicrobial treatment options remain scarce. In the absence of a universal treatment for these CPE invasive infections, individual treatment options tailored to susceptibilities and severity of infection are required. This working group from within the UK Clinical Pharmacy Association (UKCPA) Pharmacy Infection Network has developed evidence-based treatment recommendations to support infection specialists in managing these complex infections. A systematic review of peer-reviewed research was performed and analysed. We report consensus recommendations for the management of CPE-associated infections. The national expert panel makes therapeutic recommendations regarding the pharmacokinetic and pharmacodynamic properties of the drugs and pharmacokinetic targets, dosing, dosage adjustment and monitoring of parameters for novel and established antimicrobial therapies with CPE activity. This manuscript provides the infection specialist with pragmatic and evidence-based options for the management of CPE infections.

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.

Treatment of Bloodstream Infections Due to Gram-Negative Bacteria with Difficult-to-Treat Resistance

The rising incidence of bloodstream infections (BSI) due to Gram-negative bacteria (GNB) with difficult-to-treat resistance (DTR) has been recognized as a global emergency. The aim of this review is to provide a comprehensive assessment of the mechanisms of antibiotic resistance, epidemiology and treatment options for BSI caused by GNB with DTR, namely extended-spectrum Beta-lactamase-producing Enterobacteriales; carbapenem-resistant Enterobacteriales; DTR Pseudomonas aeruginosa; and DTR Acinetobacter baumannii.

Antibiotics for complicated urinary tract infection and acute pyelonephritis: A systematic review

BACKGROUND

The increasing rates of antibiotic-resistance in recent years have supported emergence of multiple drug-resistant bacteria. Therefore, antibiotics that are recommended by the current clinical guidelines may not be effective for the treatment of complicated urinary tract infection (UTI) and acute pyelonephritis.

AIM

To determine the clinical efficacy and safety of antibiotics for the treatment of complicated UTI and acute pyelonephritis.

METHOD

A search of PubMed, EMBASE, and Google Scholar was conducted for eligible articles describing the use of antibiotics in managing complicated UTI and acute pyelonephritis. The following keywords were used to perform the literature search: “urinary tract infection”, “complicated UTI”, “pyelonephritis”, “treatment”, and “antibiotics”. Additional articles of interest were retrieved from the reference lists of selected papers. Eligibility criteria for this systematic review were diagnosis of either complicated UTI or acute pyelonephritis and use of antibiotics in management. Clinical trials and observational studies were included, while case reports and reviews were excluded. The methodological quality of clinical trials and observational studies was assessed. A descriptive approach was adopted to analyze the data, due to the variation of methodology and interventions.

RESULT

A total of 183 studies were screened, and 8 matched all the eligibility criteria and were included in this review. The antibiotics used included ceftazidime-avibactam, doripenem, levofloxacin, meropenem-vaborbactam, piperacillin-tazobactam, plazomicin, tazobactam-ceftolozane, and gentamicin. Two clinical trials reported that shorter-duration levofloxacin or non-fluoroquinolone antibiotic treatment was as effective as the duration of antibiotic therapy recommended by the current guidelines in treating complicated UTI and pyelonephritis. Besides that, ceftazidime-avibactam, piperacillin-tazobactam and tazobactam-ceftolozane can be used as alternatives to carbapenem in treating extended-spectrum -lactamase-producing Escherichia coli. The cure rates of complicated UTI and pyelonephritis by meropenem-vaborbactam, piperacillin-tazobactam and tazobactam-ceftolozane was comparable (95.6%-98.4%). Furthermore, levofloxacin had a relatively high rate of adverse events (33.1% and 47.7% in two clinical trials respectively), while tazobactam-ceftolozane had a relatively low rate of adverse events (17.5%). All studies have limitations and a potential for bias.

CONCLUSION

N

Review of therapeutic options for infections with carbapenem-resistant Klebsiella pneumoniae

Infections with multi-drug resistant (MDR) bacteria including carbapenem-resistant Klebsiella pneumoniae are emerging worldwide but are difficult to treat with the currently available antibiotic compounds and therefore constitute serious threats to human health. This prompted us to perform a literature survey applying the MEDLINE database and Cochrane Register of Controlled Trials including clinical trials comparing different treatment regimens for infections caused by carbapenem-resistant K. pneumoniae. Our survey revealed that a combined application of antibiotic compounds such as meropenem plus vaborbactam, meropenem plus colistin and carbapenem plus carbapenem, resulted in significantly increased clinical cure and decreased mortality rates as compared to respective control treatment. However, further research on novel antibiotic compounds, but also on antibiotic-independent molecules providing synergistic or at least resistance-modifying properties needs to be undertaken in vitro as well as in large clinical trials to provide future options in the combat of emerging life-threatening infections caused by MDR bacteria.

Multidrug-resistant organisms in urinary tract infections in children

The global spread of multidrug-resistant organisms has led to an increase in urinary tract infections (UTIs) in children that are difficult to treat. This review explores the current literature regarding multidrug-resistant UTIs in childhood and proposes an approach to management. Multidrug-resistant organisms include a wide range of potential urinary tract pathogens and, while most literature on drug resistance in UTIs during childhood has focused on extended-spectrum beta-lactamase producing organisms, in this review, we have included a discussion of multidrug resistance including and beyond beta-lactamase production. We provide definitions for multidrug-resistant organisms in line with current consensus guidelines and summarise clinically relevant mechanisms of resistance. Additionally, in this review, we outline the global epidemiology of multidrug-resistant UTIs in children, summarising published prevalence rates, which range from 5 to 90% in different settings. Finally, we also critically review the evidence on risk factors for colonisation and infection of the urinary tract with multidrug-resistant organisms, including prior antibiotic use, hospitalisation and underlying urological malformations. We also highlight multidrug-resistant UTI occurring in children without any identifiable risk factors, reflecting an increasing prevalence of colonisation with these organisms in the general community. Taken as a whole, this emphasises a need for careful and evidence-based use of antibiotics when treating UTIs in children and, to aide clinicians, we have outlined here potential management strategies for when infection with a multidrug-resistant organism is suspected or confirmed.

Substituted Furanocoumarins as Novel Class of Antibacterial Translation Inhibitors

INTRODUCTION

A variety of organic compounds has been reported to have antibacterial activity. However, antimicrobial resistance is one of the main problems of current anti-infective therapy, and the development of novel antibacterials is one of the main challenges of current drug discovery.

METHODS

Using our previously developed dual-reporter High-Throughput Screening (HTS) platform, we identified a series of furanocoumarins as having high antibacterial activity. The construction of the reporter system allows us to differentiate three mechanisms of action for the active compounds: inhibition of protein synthesis (induction of Katushka2S), DNA damaging (induction of RFP) or other (inhibition of bacterial growth without reporter induction).

RESULTS

Two primary hit-molecules of furanocoumarin series demonstrated relatively low MIC values comparable to that observed for Erythromycin (Ery) against E. coli and weakly induced both reporters. Dose-dependent translation inhibition was shown using in vitro luciferase assay, however it was not confirmed using C14-test. A series of close structure analogs of the identified hits was obtained and investigated using the same screening platform. Compound 19 was found to have slightly lower MIC value (15.18 µM) and higher induction of Katushka2S reporter in contrast to the parent structures. Moreover, translation blockage was clearly identified using both in vitro luciferase assay and C14 test. The standard cytotoxicity test revealed a relatively low cytotoxicity of the most active molecules.

CONCLUSION

High antibacterial activity in combination with low cytotoxicity was demonstrated for a series of furanocoumarins. Further optimization of the described structures may result in novel and attractive lead compounds with promising antibacterial efficiency.

Epidemiology, definition and treatment of complicated urinary tract infections

UTIs are amongst the most frequent bacterial infections. However, the clinical phenotypes of UTI are heterogeneous and range from rather benign, uncomplicated infections to complicated UTIs (cUTIs), pyelonephritis and severe urosepsis. Stratification of patients with UTIs is, therefore, important. Several classification systems exist for the description and classification of UTIs, with the common rationale that cUTIs have a higher risk of recurrence or chronification, progression or severe outcome than uncomplicated UTIs. The pathophysiology and treatment of cUTIs and pyelonephritis are driven more by host factors than by pathogen attributes. cUTIs and pyelonephritis are associated with high antimicrobial resistance rates among causative pathogens. However, antimicrobial resistance rates can differ substantially, depending on the population being studied and whether the data being analysed are from surveillance studies, registry data or interventional studies, in which specific inclusion and exclusion criteria are used for patient selection. For example, antibiotic resistance rates are higher in patients with urosepsis than in those with less severe infections. Thus, treatment outcomes differ substantially among studies, ranging from 50% to almost 100% clearance of infection, depending on the patient population analysed, the UTI entities included and the primary outcome of the study. Pyelonephritis and cUTIs have emerged as infection models for the study of novel antibiotics, including extensive investigation of novel substances active against Gram-negative bacteria.

The Infectious Diseases Society of America's 10 × '20 Initiative (10 New Systemic Antibacterial Agents US Food and Drug Administration Approved by 2020): Is 20 × '20 a Possibility?

BACKGROUND

Infections caused by antibiotic-resistant bacteria, including carbapenem-resistant Enterobacteriaceae, have increased in frequency, resulting in significant patient morbidity and mortality. The Infectious Diseases Society of America continues to propose legislative, regulatory, and funding solutions to address this escalating crisis. This report updates the status of development and approval of systemic antibiotics in the United States as of late 2018.

METHODS

We performed a review of the published literature and on-line clinical trials registry at www.clinicaltrials.gov to identify new systemically acting orally and/or intravenously administered antibiotic drug candidates in the development pipeline, as well as agents approved by the US Food and Drug Administration since 2012.

RESULTS

Since our 2013 pipeline status report, the number of new antibiotics annually approved for marketing in the United States has reversed its previous decline, likely influenced by new financial incentives and increased regulatory flexibility. Although our survey demonstrates progress in development of new antibacterial drugs that target infections caused by resistant bacterial pathogens, the majority of recently approved agents have been modifications of existing chemical classes of antibiotics, rather than new chemical classes. Furthermore, larger pharmaceutical companies continue to abandon the field, and smaller companies face financial difficulties as a consequence.

CONCLUSIONS

Unfortunately, if 20 × '20 is achieved due to efforts embarked upon in decades past, it could mark the apex of antibiotic drug development for years to come. Without increased regulatory, governmental, industry, and scientific support and collaboration, durable solutions to the clinical, regulatory, and economic problems posed by bacterial multidrug resistance will not be found.