The rise of antimicrobial resistance (AMR) remains a global crisis. Collectively, antimicrobial-resistant pathogens caused more than 2.8 million infections and more than 35,000 deaths annually between 2012 and 2017, according to the Centers for Disease Control and Prevention’s Antibiotic Resistance Threat Report in the United States. Disease Control and Prevention (CDC) 2019.
The Infectious Diseases Society of America (IDSA) identified the development and dissemination of clinical practice guidelines and other guidance products for physicians as a major initiative in its 2019 Strategic Plan . Background:
The Infectious Diseases Society of America (IDSA) is committed to providing up-to-date guidance on the treatment of antimicrobial-resistant infections. A previous guidance document focused on infections caused by extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E), carbapenem-resistant Enterobacterales (CRE), and difficult-to-treat resistance Pseudomonas aeruginosa (DTR-P. aeruginosa).
Here, guidance is provided for the treatment of AmpC β-lactamase-producing Enterobacterales (AmpC-E), carbapenem-resistant Acinetobacter baumannii (CRAB), and Stenotrophomonas maltophilia.
Methods:
A panel of six infectious disease specialists with experience managing antimicrobial-resistant infections asked questions about the treatment of AmpC-E, CRAB, and S. maltophilia infections.
The answers are presented as suggested approaches and corresponding rationales. Unlike the guidance in the previous paper, published data on the optimal treatment of AmpC-E, CRAB and S. maltophilia infections are limited.
As such, the guidance in this document is provided as "suggested approaches" based on clinical experience, expert opinion, and a review of available literature. Due to differences in the epidemiology of resistance and the international availability of specific anti-infectives, this document focuses on the treatment of infections in the United States.
Results:
Suggestions for preferred and alternative treatments are provided, assuming the causative organism has been identified and antibiotic susceptibility results are known. Empirical treatment approaches, duration of therapy, and other management considerations are also briefly discussed. The suggestions apply to both the adult and pediatric populations.
Conclusions:
The field of antimicrobial resistance is very dynamic. Consultation with an infectious disease specialist is recommended for the treatment of antimicrobial-resistant infections.
This document is current as of September 17, 2021 and will be updated annually. The most current version of this document, including the date of publication, is available at www.idsociety.org/practice-guideline/amr-guidance-2.0/ .
General recommendations
The treatment recommendations in this guidance document assume that the causative organism has been identified and the in vitro activity of the antibiotics has been demonstrated.
Assuming that two antibiotics are equally effective, safety, cost, convenience, and local formulary availability are important considerations when selecting a specific agent.
The panel recommends that infectious disease specialists and physician or pharmacist members of the local antibiotic stewardship program be involved in the management of patients with infections caused by antimicrobial-resistant organisms.
Empirical therapy
Empirical treatment decisions should be guided by the most likely pathogens, the severity of the patient’s illness, the likely source of infection, and any additional patient-specific factors (e.g., severe penicillin allergy, chronic kidney disease). .
When determining empiric treatment for a given patient, clinicians should also consider: (1) the patient’s prior identified organisms and associated antibiotic susceptibility data in the past six months, (2) antibiotic exposures in the past 30 days, and ( 3) local susceptibility patterns for the most likely pathogens.
Empirical decisions should be refined based on the identity and susceptibility profile of the pathogen, as well as the identification of any prominent β-lactamase genes.
For CRAB and S. maltophilia, in particular, it is important to distinguish between bacterial colonization and infection , as unnecessary antibiotic therapy will only promote the development of resistance and may cause unnecessary antibiotic-related harm to patients.
Commonly selected empiric antibiotic regimens are generally not active against CRAB and S. maltophilia infections. The decision to direct treatment for CRAB and/or S. maltophilia to empiric antibiotic regimens should involve a careful risk-benefit analysis after reviewing previous culture results, clinical presentation, individual host risk factors, and Antibiotic-specific adverse event profiles.
Duration of therapy and transition to oral therapy
No recommendations are provided on the duration of therapy, but clinicians are cautioned that prolonged treatments are not necessary against infections caused by antimicrobial-resistant pathogens per se , compared to infections caused by the same bacterial species with a more aggressive phenotype. susceptible.
Once antibiotic susceptibility results are available, it may be evident that inactive antibiotic therapy was initiated empirically. This may affect the duration of therapy. For example, cystitis is usually a mild infection.
If an antibiotic that is not active against the causative organism for cystitis was empirically administered, but clinical improvement nevertheless occurred , the panelists agree that it is generally not necessary to repeat a urine culture, change the antibiotic regimen, or extend the course. planned course of treatment.
However, for all other infections, if antibiotic susceptibility data indicate that a potentially inactive agent was started empirically, a switch to an effective regimen is recommended for a full treatment course (dated from the start of active therapy ).
Additionally, when determining the duration of treatment for antimicrobial-resistant infections, as with the treatment of any bacterial infection, important host factors related to immune status, ability to achieve source control, and general response to therapy.
Finally, whenever possible, oral reducing therapy should be considered , particularly if the following criteria are met: (1) susceptibility to an appropriate oral agent is demonstrated, (2) the patient is hemodynamically stable, (3) reasonable measures of source control have occurred, and (4) concerns about insufficient intestinal absorption are not present.
It is true that meeting these criteria can be a challenge with CRAB and furthermore, when determining the duration of treatment for antimicrobial-resistant infections, as with the treatment of any bacterial infection, important host factors related to the immune status, the ability to achieve source control, and overall response to therapy.
