Application of the Hartford Hospital Nomogram for Plazomicin Dosing Interval Selection in Patients with Complicated Urinary Tract Infection

Antimicrobial Treatment Options for Difficult-to-Treat Resistant Gram-Negative Bacteria Causing Cystitis, Pyelonephritis, and Prostatitis: A Narrative Review

Urinary tract infections, including cystitis, acute pyelonephritis, and prostatitis, are among the most common diagnoses prompting antibiotic prescribing. The rise in antimicrobial resistance over the past decades has led to the increasing challenge of urinary tract infections because of multidrug-resistant and "difficult-to-treat resistance" among Gram-negative bacteria. Recent advances in pharmacotherapy and medical microbiology are modernizing how these urinary tract infections are treated. Advances in pharmacotherapy have included not only the development and approval of novel antibiotics, such as ceftazidime/avibactam, meropenem/vaborbactam, imipenem/relebactam, ceftolozane/tazobactam, cefiderocol, plazomicin, and glycylcyclines, but also the re-examination of the potential role of legacy antibiotics, including older aminoglycosides and tetracyclines. Recent advances in medical microbiology allow phenotypic and molecular mechanism of resistance testing, and thus antibiotic prescribing can be tailored to the mechanism of resistance in the infecting pathogen. Here, we provide a narrative review on the clinical and pre-clinical studies of drugs that can be used for difficult-to-treat resistant Gram-negative bacteria, with a particular focus on data relevant to the urinary tract. We also offer a pragmatic framework for antibiotic selection when encountering urinary tract infections due to difficult-to-treat resistant Gram-negative bacteria based on the organism and its mechanism of resistance.

Plazomicin: a new aminoglycoside in the fight against antimicrobial resistance

Objective

To review the mechanism of action, mechanisms of resistance, in vitro activity, pharmacokinetics, pharmacodynamics, and clinical data for a novel aminoglycoside.

Data sources

A PubMed search was performed from January 2006 to August 2019 using the following search terms: plazomicin and ACHN-490. Another search was conducted on clinicaltrials.gov for published clinical data. References from selected studies were also used to find additional literature.

Study selection and data extraction

All English-language studies presenting original research (in vitro, in vivo, pharmacokinetic, and clinical) were evaluated.

Data synthesis

Plazomicin has in vitro activity against several multi-drug-resistant organisms, including carbapenem-resistant Enterobacteriaceae. It was Food and Drug Administration (FDA) approved to treat complicated urinary tract infections (cUTIs), including acute pyelonephritis, following phase II and III trials compared with levofloxacin and meropenem, respectively. Despite the FDA Black Box Warning for aminoglycoside class effects (nephrotoxicity, ototoxicity, neuromuscular blockade, and pregnancy risk), it exhibited a favorable safety profile with the most common adverse effects being decreased renal function (3.7%), diarrhea (2.3%), hypertension (2.3%), headache (1.3%), nausea (1.3%), vomiting (1.3%), and hypotension (1.0%) in the largest in-human trial.

Relevance to patient care and clinical practice

Plazomicin will likely be used in the treatment of multi-drug-resistant cUTIs or in combination to treat serious carbapenem-resistant Enterobacteriaceae infections.

Conclusions

Plazomicin appears poised to help fill the need for new agents to treat infections caused by multi-drug-resistant Enterobacteriaceae.

Plazomicin: an intravenous aminoglycoside antibacterial for the treatment of complicated urinary tract infections

INTRODUCTION

Antimicrobial resistance continues to be a major public health concern due to the emergence and spread of multi-drug resistant (MDR) organisms, including extended spectrum ß-lactamase (ESBL) and carbapenemase producing Enterobacterales. Plazomicin is a novel aminoglycoside that demonstrates activity against MDR gram-negatives, including those producing ESBLs and most carbapenemases, and retains activity against aminoglycoside modifying enzymes as a result of structural modifications. The information discussed is meant to assist in identifying plazomicin's place in therapy and to expand the clinician's armamentarium.

AREAS COVERED

Herein, we review the pharmacology, microbiology, clinical efficacy, and safety of plazomicin. To gather relevant information, a literature search was performed using PubMed, Ovid, and Google Scholar electronic databases. Search terms used include plazomicin, ACHN-490, extended spectrum ß-lactamase, ESBL, CRE, aminoglycoside modifying enzymes, and AME. Additional information was obtained from FDA review documents and research abstracts presented at international conferences.

EXPERT OPINION

Plazomicin is a promising carbapenem or β-lactam/β-lactamase inhibitor-sparing alternative for the treatment of complicated urinary tract infections caused by MDR Enterobacterales. Although robust data for bloodstream infections and bacterial pneumonias are lacking, plazomicin may be considered in individual clinical scenarios if combination therapy is warranted provided supportive microbiological data and therapeutic drug monitoring are available.

Carbapenem-Resistant Enterobacterales: Considerations for Treatment in the Era of New Antimicrobials and Evolving Enzymology

Purpose of Review

Gram-negative resistance is a growing concern globally. Enterobacterales, formerly Enterobacteriaceae, have developed resistance mechanisms to carbapenems that leave very few antimicrobial options in the clinician’s armamentarium.

Recent Findings

New antimicrobials like ceftazidime-avibactam, meropenem-vaborbactam, imipenem-relebactam, cefiderocol, and plazomicin have the potential to overcome resistance mechanisms in Enterobacterales including different classes of carbapenemases.

Summary

Novel β-lactam/β-lactamase inhibitors, plazomicin, and cefiderocol give the clinician options that were once not available. Utilizing these options is of the utmost importance when treating carbapenem-resistant Enterobacterales.