mk-7655 and Gram-Negative-Bacterial-Infections

Infections due to multidrug-resistant (MDR) Gram-negative bacteria are challenging to treat because of limited treatment options and potential side effects of less frequently used anti-infectives. In the past few years, several new antimicrobial agents effective against MDR Gram-negatives have become available. This review focuses on the treatment options for complicated urinary tract infections (cUTIs) caused by MDR Gram-negatives.. The novel combinations, betalactam or carbapenem and betalactamase inhibitor, ceftazidime/avibactam and meropenem/vaborbactam, are effective for infections caused by KPC-carbapenemase-producing pathogens. Imipenem/relebactam, another carbapenem/betalactamase inhibitor combination, has been approved for the treatment of cUTI. However, data on the efficacy of imipenem/relebactam against carbapenem-resistant pathogens is still limited. Ceftolozane/tazobactam is mainly used for the treatment of MDR Pseudomonas aeruginosa infections. For the treatment of cUTI caused by extended-spectrum betalactamases producing Enterobacterales aminoglycosides or intravenous fosfomycin should be considered.. To ensure prudent use and to avoid the development of resistance to novel anti-infective substances, an interdisciplinary approach, including urologists, microbiologists, and infectious disease physicians, is strongly advised.

Topics: Anti-Bacterial Agents; beta-Lactamase Inhibitors; Carbapenems; Gram-Negative Bacterial Infections; Humans; Imipenem; Urinary Tract Infections

The superiority of combination therapy for carbapenem-resistant Gram-negative bacilli (CR-GNB) infections remains controversial. In vitro models may predict the efficacy of antibiotic regimens against CR-GNB. A systematic review and meta-analysis was performed including pharmacokinetic/pharmacodynamic (PK/PD) and time-kill (TK) studies examining the in vitro efficacy of antibiotic combinations against CR-GNB [PROSPERO registration no. CRD42019128104]. The primary outcome was in vitro synergy based on the effect size (ES): high, ES ≥ 0.75, moderate, 0.35 < ES < 0.75; low, ES ≤ 0.35; and absent, ES = 0). A network meta-analysis assessed the bactericidal effect and re-growth rate (secondary outcomes). An adapted version of the ToxRTool was used for risk-of-bias assessment. Over 180 combination regimens from 136 studies were included. The most frequently analysed classes were polymyxins and carbapenems. Limited data were available for ceftazidime/avibactam, ceftolozane/tazobactam and imipenem/relebactam. High or moderate synergism was shown for polymyxin/rifampicin against Acinetobacter baumannii [ES = 0.91, 95% confidence interval (CI) 0.44-1.00], polymyxin/fosfomycin against Klebsiella pneumoniae (ES = 1.00, 95% CI 0.66-1.00) and imipenem/amikacin against Pseudomonas aeruginosa (ES = 1.00, 95% CI 0.21-1.00). Compared with monotherapy, increased bactericidal activity and lower re-growth rates were reported for colistin/fosfomycin and polymyxin/rifampicin in K. pneumoniae and for imipenem/amikacin or imipenem/tobramycin against P. aeruginosa. High quality was documented for 65% and 53% of PK/PD and TK studies, respectively. Well-designed in vitro studies should be encouraged to guide the selection of combination therapies in clinical trials and to improve the armamentarium against carbapenem-resistant bacteria.

Topics: Amikacin; Anti-Bacterial Agents; Azabicyclo Compounds; Carbapenems; Ceftazidime; Cephalosporins; Colistin; Drug Combinations; Drug Resistance, Bacterial; Drug Synergism; Drug Therapy, Combination; Fosfomycin; Gram-Negative Bacteria; Gram-Negative Bacterial Infections; Humans; Imipenem; In Vitro Techniques; Microbial Sensitivity Tests; Polymyxins; Rifampin; Tazobactam; Tobramycin

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.

Topics: Anti-Bacterial Agents; Azabicyclo Compounds; Boronic Acids; Cefiderocol; Ceftazidime; Cephalosporins; Cilastatin, Imipenem Drug Combination; Drug Combinations; Drug Design; Drug Resistance, Multiple; Gram-Negative Bacteria; Gram-Negative Bacterial Infections; Heterocyclic Compounds, 1-Ring; Humans; Meropenem; Sisomicin; Tazobactam; Tetracyclines

Imipenem-cilastatin-relebactam (IMI-REL) is a novel β-lactam-β-lactamase inhibitor combination recently approved for the treatment of complicated urinary tract infections (cUTIs) and complicated intraabdominal infections (cIAIs). Relebactam is a β-lactamase inhibitor with the ability to inhibit a broad spectrum of β-lactamases such as class A and class C β-lactamases, including carbapenemases. The addition of relebactam to imipenem restores imipenem activity against several imipenem-resistant bacteria, including Enterobacteriaceae and Pseudomonas aeruginosa. Clinical data demonstrate that IMI-REL is well tolerated and effective in the treatment of cUTIs and cIAIs due to imipenem-resistant bacteria. In a phase III trial comparing IMI-REL with imipenem plus colistin, favorable clinical response was achieved in 71% and 70% of patients, respectively. Available clinical and pharmacokinetic data support the approved dosage of a 30-minute infusion of imipenem 500 mg-cilastatin 500 mg-relebactam 250 mg every 6 hours, along with dosage adjustments based on renal function. In this review, we describe the chemistry, mechanism of action, spectrum of activity, pharmacokinetics and pharmacodynamics, and clinical efficacy, and safety and tolerability of this new agent. The approval of IMI-REL represents another important step in the ongoing fight against multidrug-resistant gram-negative pathogens.

Topics: Anti-Bacterial Agents; Azabicyclo Compounds; Cilastatin; Drug Resistance, Multiple, Bacterial; Drug Therapy, Combination; Gram-Negative Bacteria; Gram-Negative Bacterial Infections; Humans; Imipenem; Microbial Sensitivity Tests

To discuss a possible clinical reasoning for treating resistant Gram-negative bacteria (GNB) infections in daily clinical practice, as well as developing a research agenda for the field.. Novel agents, both belonging to β-lactams and to other classes of antimicrobials, have recently become available, likely replacing polymyxins or polymyxin-based combination regimens as the preferred choices for the first-line treatment of severe resistant GNB infections in the near future.. The peculiar characteristics of novel agents for severe resistant GNB infections have abruptly made the structure of previous therapeutic algorithms somewhat obsolete, in view of the differential activity of most of them against different classes of carbapenemases. Furthermore, other agents showing activity against resistant GNB are in late phase of clinical development. Optimizing the use of novel agents in order both to guarantee the best available treatment to patients and to delay the emergence and spread of resistance is an important task that cannot be postponed, especially considering the unavailability of well tolerated and fully efficacious options for treating resistant GNB infections that we faced in the last 15 years.

Topics: Anti-Bacterial Agents; Anti-Infective Agents; Azabicyclo Compounds; beta-Lactams; Carbapenems; Cefiderocol; Ceftazidime; Cephalosporins; Drug Combinations; Drug Resistance, Bacterial; Gram-Negative Bacterial Infections; Humans; Imipenem; Microbial Sensitivity Tests; Polymyxins; Sisomicin; Tazobactam; Tetracyclines

With the current carbapenem-resistant organism crisis, conventional approaches to optimizing pharmacokinetic-pharmacodynamic parameters are frequently inadequate, and traditional salvage agents (eg, colistin, tigecycline, etc) confer high toxicity and/or have low efficacy. However, several β-lactam agents with activity against carbapenem-resistant organisms were approved recently by the US Food and Drug Administration, and more are anticipated to be approved in the near future. The primary goal of this review is to assist infectious disease practitioners with preferentially selecting 1 agent over another when treating patients infected with a carbapenem-resistant organism. However, resistance to some of these antibiotics has already developed. Antibiotic stewardship programs can ensure that they are reserved for situations in which other options are lacking and are paramount for the survival of these agents.

Topics: Anti-Bacterial Agents; Azabicyclo Compounds; Aztreonam; Boronic Acids; Carbapenems; Cefiderocol; Ceftazidime; Cephalosporins; Cilastatin, Imipenem Drug Combination; Drug Combinations; Drug Resistance, Multiple, Bacterial; Gram-Negative Bacteria; Gram-Negative Bacterial Infections; Heterocyclic Compounds, 1-Ring; Meropenem; Tazobactam

As the incidence of Gram-negative bacterial infections for which few effective treatments remain increases, so does the contribution of drug-hydrolyzing β-lactamase enzymes to this serious clinical problem. This review highlights recent advances in β-lactamase inhibitors and focuses on agents with novel mechanisms of action against a wide range of enzymes. To this end, we review the β-lactamase inhibitors currently in clinical trials, select agents still in preclinical development, and older therapeutic approaches that are being revisited. Particular emphasis is placed on the activity of compounds at the forefront of the developmental pipeline, including the diazabicyclooctane inhibitors (avibactam and MK-7655) and the boronate RPX7009. With its novel reversible mechanism, avibactam stands to be the first new β-lactamase inhibitor brought into clinical use in the past 2 decades. Our discussion includes the importance of selecting the appropriate partner β-lactam and dosing regimens for these promising agents. This "renaissance" of β-lactamase inhibitors offers new hope in a world plagued by multidrug-resistant (MDR) Gram-negative bacteria.

Topics: Anti-Bacterial Agents; Azabicyclo Compounds; beta-Lactamase Inhibitors; Drug Resistance, Multiple, Bacterial; Enzyme Inhibitors; Gram-Negative Bacteria; Gram-Negative Bacterial Infections; Humans; Microbial Sensitivity Tests

The RESTORE-IMI 1 phase 3 trial demonstrated the efficacy and safety of imipenem-cilastatin (IMI) combined with relebactam (REL) for treating imipenem-nonsusceptible infections. The objective of this analysis was to compare the outcomes among patients meeting eligibility requirements based on central laboratory susceptibility versus local laboratory susceptibility. Patients with serious infections caused by imipenem-nonsusceptible, colistin-susceptible, and imipenem-REL-susceptible pathogens were randomized 2:1 to IMI-REL plus placebo or colistin plus IMI for 5 to 21 days. The primary endpoint was a favorable overall response. Key endpoints included the clinical response and all-cause mortality. We compared outcomes between the primary microbiological modified intent-to-treat (mMITT) population, where eligibility was based on central laboratory susceptibility testing, and the supplemental mMITT (SmMITT) population, where eligibility was based on local, site-level testing. The SmMITT (

Topics: Adult; Age Factors; Aged; Aged, 80 and over; Anti-Bacterial Agents; Azabicyclo Compounds; beta-Lactamase Inhibitors; Cilastatin, Imipenem Drug Combination; Colistin; Drug Resistance, Multiple, Bacterial; Endpoint Determination; Female; Gram-Negative Bacterial Infections; Humans; Imipenem; Kidney; Male; Microbial Sensitivity Tests; Middle Aged; Sex Factors; Treatment Outcome; Young Adult

The β-lactamase inhibitor relebactam can restore imipenem activity against imipenem non-susceptible pathogens.. To explore relebactam's safety, tolerability and efficacy, we conducted a randomized (1:1:1), controlled, Phase 2 trial comparing imipenem/cilastatin+relebactam 250 mg, imipenem/cilastatin+relebactam 125 mg and imipenem/cilastatin alone in adults with complicated urinary tract infections (cUTI) or acute pyelonephritis, regardless of baseline pathogen susceptibility. Treatment was administered intravenously every 6 h for 4-14 days, with optional step-down to oral ciprofloxacin. The primary endpoint was favourable microbiological response rate (pathogen eradication) at discontinuation of intravenous therapy (DCIV) in the microbiologically evaluable (ME) population. Non-inferiority of imipenem/cilastatin+relebactam over imipenem/cilastatin alone was defined as lower bounds of the 95% CI for treatment differences being above -15%.. At DCIV, 71 patients in the imipenem/cilastatin + 250 mg relebactam, 79 in the imipenem/cilastatin + 125 mg relebactam and 80 in the imipenem/cilastatin-only group were ME; 51.7% had cUTI and 48.3% acute pyelonephritis. Microbiological response rates were 95.5%, 98.6% and 98.7%, respectively, confirming non-inferiority of both imipenem/cilastatin + relebactam doses to imipenem/cilastatin alone. Clinical response rates were 97.1%, 98.7% and 98.8%, respectively. All 23 ME patients with imipenem non-susceptible pathogens had favourable DCIV microbiological responses (100% in each group). Among all 298 patients treated, 28.3%, 29.3% and 30.0% of patients, respectively, had treatment-emergent adverse events. The most common treatment-related adverse events across groups (1.0%-4.0%) were diarrhoea, nausea and headache.. Imipenem/cilastatin + relebactam (250 or 125 mg) was as effective as imipenem/cilastatin alone for treatment of cUTI. Both relebactam-containing regimens were well tolerated. (NCT01505634).

Topics: Administration, Intravenous; Adolescent; Adult; Aged; Aged, 80 and over; Anti-Bacterial Agents; Azabicyclo Compounds; beta-Lactamase Inhibitors; Cilastatin; Cilastatin, Imipenem Drug Combination; Double-Blind Method; Drug Combinations; Drug Therapy, Combination; Female; Gram-Negative Bacterial Infections; Humans; Imipenem; Male; Middle Aged; Prospective Studies; Pyelonephritis; Urinary Tract Infections; Young Adult

We assessed the antibacterial effect of human simulations of dosing with imipenem/relebactam (with or without amikacin) on Enterobacteriaceae or Pseudomonas aeruginosa over 7 or 14 day antibiotic exposures.. An in vitro pharmacokinetic model was used to assess changes in bacterial load and population profiles.. Imipenem/relebactam produced an initial >4 log drop in viable counts followed by suppression for 7 days for Enterobacteriaceae whether the strain was WT, produced KPC enzymes or produced an AmpC enzyme with porin loss. Similarly, with the P. aeruginosa strains, there was an initial >4 log clearance over the first 24 h irrespective of whether the strain was WT, hyperexpressed AmpC or had OprD mutation with porin loss. However, with three of four strains there was modest regrowth over the 7 days. There were no changes in imipenem/relebactam MICs over the 7 days. Addition of amikacin in 7 day simulations resulted in more suppression of pseudomonal growth. In 14 day simulations with P. aeruginosa there was regrowth to 8 log10 by 14 days with imipenem/relebactam alone and associated increases in MICs. Addition of amikacin resulted in clearance from the model and prevented changes in population profiles.. Imipenem/relebactam was highly effective at reducing the bacterial load of Enterobacteriaceae and there was no emergence of resistance. Against P. aeruginosa, the initial bacterial burden was also rapidly reduced, but there was subsequent regrowth, especially after 7 days of exposure. Addition of amikacin increased the clearance of P. aeruginosa and prevented emergence of resistance.

Topics: Anti-Bacterial Agents; Azabicyclo Compounds; Computer Simulation; Dose-Response Relationship, Drug; Gram-Negative Bacteria; Gram-Negative Bacterial Infections; Humans; Imipenem; Microbial Sensitivity Tests; Time Factors

Topics: Animals; Azabicyclo Compounds; beta-Lactamase Inhibitors; Drug Resistance, Multiple, Bacterial; Gram-Negative Bacterial Infections; Imipenem; Klebsiella pneumoniae; Mice; Microbial Sensitivity Tests

Relebactam is an inhibitor of class A β-lactamases, including KPC β-lactamases, and class C β-lactamases, and is currently under clinical development in combination with imipenem. The objective of the current study was to evaluate the in vitro activity of imipenem/relebactam against Gram-negative ESKAPE pathogens (Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.) submitted by clinical laboratories in 17 European countries to the Study for Monitoring Antimicrobial Resistance Trends (SMART) global surveillance programme in 2015.. MICs were determined using the CLSI standard broth microdilution method and interpreted using EUCAST clinical breakpoints. Relebactam was tested at a fixed concentration of 4 mg/L in combination with doubling dilutions of imipenem. Imipenem/relebactam MICs were interpreted using breakpoints for imipenem.. Rates of susceptibility to imipenem and imipenem/relebactam for isolates of P. aeruginosa (n = 1705), K. pneumoniae (n = 1591) and Enterobacter spp. (n = 772) were 72.0/94.7%, 88.7/94.8% and 95.6/96.8%, respectively. Relebactam restored imipenem susceptibility to 81.1%, 54.2% and 26.5% of imipenem-non-susceptible isolates of P. aeruginosa (n = 477), K. pneumoniae (n = 179) and Enterobacter spp. (n = 34). Most imipenem/relebactam-non-susceptible isolates carried MBLs, OXA-48 or GES carbapenemases. Relebactam did not increase the number of isolates of A. baumannii (n = 486) susceptible to imipenem.. Relebactam restored susceptibility to imipenem for the majority of imipenem-non-susceptible isolates of P. aeruginosa and K. pneumoniae tested as well as some isolates of imipenem-non-susceptible Enterobacter spp. Based on our results, imipenem/relebactam appears to be a promising therapeutic option for treating patients with infections caused by antimicrobial-resistant Gram-negative bacilli.

Topics: Acinetobacter baumannii; Anti-Bacterial Agents; Azabicyclo Compounds; Bacterial Proteins; beta-Lactamase Inhibitors; beta-Lactamases; Enterobacter; Europe; Gram-Negative Bacteria; Gram-Negative Bacterial Infections; Humans; Imipenem; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Sentinel Surveillance

Antimicrobial resistance is increasing worldwide and is especially problematic in ICUs. Relebactam is a new bicyclic diazabicyclooctane β-lactamase inhibitor of class A and C β-lactamases that is in development in combination with imipenem. This study describes geographical resistance patterns among isolates from ICU and non-ICU wards in seven global regions and examines the activity of imipenem/relebactam in these settings.. In 2015-2016, 194 hospitals from 55 countries each collected up to 100 consecutive Gram-negative pathogens from intra-abdominal, 100 from lower respiratory and 50 from urinary tract infections per year. Susceptibility was determined for 45699 non-Proteeae Enterobacteriaceae (NPE) and 10834 Pseudomonas aeruginosa using CLSI broth microdilution and breakpoints, with imipenem breakpoints applied to imipenem/relebactam.. Isolates from ICUs were more resistant to almost all tested agents across regions and infection sources. The size of the ICU/non-ICU difference varied, with a smaller gap in USA/Canada and South Pacific (regions with highest susceptibility) and for imipenem/relebactam, amikacin and colistin (drugs with highest activity). Susceptibility of NPE to imipenem/relebactam was >90% in ICUs in all regions except Africa (88.2%). Only amikacin exceeded these rates in most regions. Against cefepime-non-susceptible and multidrug-resistant (MDR) NPE from ICUs, imipenem/relebactam maintained activity >90% in three regions and >80% in the remaining regions except Africa (75%). Susceptibility of P. aeruginosa was >90% in ICUs in USA/Canada, South Pacific and Europe and >82% elsewhere.. Imipenem/relebactam could provide a valuable therapeutic option in ICUs, especially against MDR isolates and those non-susceptible to other β-lactam antibiotics.

Topics: Anti-Bacterial Agents; Azabicyclo Compounds; Drug Resistance, Bacterial; Gram-Negative Bacteria; Gram-Negative Bacterial Infections; Humans; Imipenem; Intensive Care Units; Microbial Sensitivity Tests