Four key recommendations for treating MDRGNIs
The authors base their recommendations, in addition to the recent studies they cite concerning CZA, upon two major guidelines on the treatment of MDRGNIs: the European Society of Clinical Microbiology and Infectious Diseases’ Guidelines for the Treatment of Infections Caused by Multidrug-Resistant Gram-Negative Bacilli, and the Infectious Diseases Society of America’s (IDSA’s) Guidance on the Treatment of Antimicrobial Resistant Gram-Negative Infections (multiple documents, found here and here).
Dr. Windham and Dr. Kollef present a table showing the spectrum of activity of the newer antibiotics, as well as an algorithm for decision-making. They summarize their treatment recommendations, which are based upon the bacterial infection cultures or on historical risk (previous infection or colonization history). They encourage empiric treatment if there is an increased risk of death or the presence of shock. By pathogen, they recommend the following:
- For carbapenem-resistant Enterobacterales, clinicians should treat patients with cefiderocol, ceftazidime-avibactam, imipenem-cilastatin-relabactam, or meropenem-vaborbactam.
- For carbapenem-resistant Pseudomonas aeruginosa, clinicians should treat patients with cefiderocol, ceftazidime-avibactam, imipenem-cilastatin-relabactam, or ceftolozane-tazobactam.
- For carbapenem-resistant Acinetobacter baumanii, clinicians should treat patients with a cefiderocol backbone with or without the addition of plazomicin, eravacycline, or other older antibacterials.
- For metallo-beta-lactamase-producing organisms, clinicians should treat patients with cefiderocol, ceftazidime-avibactam, aztreonam, imipenem-cilastatin-relabactam, aztreonam, or aztreonam-avibactam. The authors acknowledge that evidence is limited on treating these infections.
“In general, ceftazidime-avibactam works pretty well in patients with MDRGNIs, and there is no evidence that any of the other new agents is conclusively better in treatment responses. CZA and ceftolozane-tazobactam were the first of the new antibiotics active against highly MDRGN to get approved, and they have been most widely used,” Cornelius “Neil” J. Clancy, MD, chief of the Infectious Diseases Section at the VA Pittsburgh Health Care System, explained. Dr. Clancy was not involved in the Windham-Kollef review article.
“As such, it is not surprising that resistance has emerged and that it has been reported more commonly than for some other agents. The issue of resistance will be considered again as IDSA puts together their update,” Dr. Clancy said.
“The IDSA guidelines are regularly updated. The next updated iteration will be online in early 2023,” said Dr. Clancy, who is also affiliated with IDSA. “Clinical and resistance data that have appeared since the last update in 2022 will be considered as the guidance is put together.”
In general, Dr. Kollef also recommends using a facility’s antibiogram. “They are useful in determining which MDRGN’s predominate locally,” he said.
Dr. Kollef is a consultant for Pfizer, Merck, and Shionogi. Dr. Clancy has received research funding from Merck and from the National Institutes of Health.
A version of this article first appeared on Medscape.com.