IDSA 2024 Guidelines for Treatment of Antimicrobial-Resistant Gram-Negative Infections – Clin Infect Dis

Introduction:

The Infectious Diseases Society of America (IDSA) has released updated guidelines in 2024 addressing the treatment of infections caused by antimicrobial-resistant (AMR) Gram-negative bacteria. These guidelines cover pathogens including extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E), AmpC β-lactamase-producing Enterobacterales (AmpC-E), carbapenem-resistant Enterobacterales (CRE), difficult-to-treat Pseudomonas aeruginosa (DTR P. aeruginosa), carbapenem-resistant Acinetobacter baumannii (CRAB), and Stenotrophomonas maltophilia.

Key Points:

1 – ESBL-E Infections:

– Preferred treatment for uncomplicated cystitis includes nitrofurantoin and TMP-SMX. Fluoroquinolones and carbapenems are alternatives but should be reserved to prevent resistance.

– For pyelonephritis or complicated urinary tract infections (cUTI), TMP-SMX, ciprofloxacin, or levofloxacin are preferred. Carbapenems are recommended when resistance precludes other options.

2 – AmpC-E Infections:

– Cefepime is suggested for treating infections caused by organisms at moderate risk of significant AmpC production (e.g., Enterobacter cloacae complex, Klebsiella aerogenes, and Citrobacter freundii).

– The use of cephamycins (e.g., cefoxitin, cefotetan) for treating ESBL-E infections is not recommended due to insufficient clinical outcome data.

3 – CRE Infections:

– Acknowledgement of increased prevalence of metallo-beta-lactamase (MBL)-producing CRE in the U.S.

– The combination of ceftazidime-avibactam and aztreonam is suggested for MBL-producing CRE, with updated dosing recommendations provided.

4 – DTR Pseudomonas aeruginosa:

– Traditional β-lactams (e.g., cefepime) with high-dose extended-infusion therapy are recommended.

– Tobramycin or amikacin, administered once daily, are alternatives for pyelonephritis or cUTI.

5 – CRAB and Stenotrophomonas maltophilia Infections:

– Sulbactam-durlobactam with meropenem or imipenem-cilastatin is the preferred treatment for CRAB.

– The order of preference for agents treating S. maltophilia includes cefiderocol, ceftazidime-avibactam, and aztreonam, among others.

Conclusion:

The 2024 IDSA guidelines provide critical updates on managing AMR Gram-negative infections, emphasizing the importance of selecting the appropriate antibiotic based on susceptibility, resistance mechanisms, and patient-specific factors. These guidelines are essential for optimizing treatment outcomes in the face of increasing antimicrobial resistance.

Reference:

Tamma, P. D., Heil, E. L., Justo, J. A., Mathers, A. J., Satlin, M. J., & Bonomo, R. A. (2024). Infectious Diseases Society of America Guidance on the Treatment of Antimicrobial-Resistant Gram-Negative Infections. Clinical Infectious Diseases.