From the Guidelines
Meropenem is no longer a reliable option for treating Acinetobacter baumannii infections due to high resistance rates, with carbapenem resistance reported as high as 75.3% in some regions 1. When considering treatment options for A. baumannii, it's essential to note that carbapenem-resistant strains are now common worldwide, and meropenem's effectiveness has significantly decreased as a result.
- Key factors contributing to this resistance include the production of carbapenemases, efflux pumps, and porin alterations that prevent the antibiotic from reaching its target.
- The high mortality rates associated with inappropriate empirical antimicrobial therapy for CRAB infections, reaching up to 86.1%, underscore the need for careful selection of antimicrobial agents based on susceptibility testing 1.
- For susceptible strains, meropenem dosing typically ranges from 1-2 grams intravenously every 8 hours, with adjustments necessary for patients with renal impairment.
- However, given the prevalence of carbapenem-resistant A. baumannii, alternative treatments such as polymyxins (colistin), tigecycline, or combination therapies are often required.
- The increasing prevalence of multidrug-resistant A. baumannii poses a significant challenge in healthcare settings, particularly in intensive care units, where these infections are most common 1.
From the Research
Effectiveness of Meropenem against A. baumannii
- Meropenem is considered one of the mainstay treatments for A. baumannii infections, although resistance to carbapenems, including meropenem, has been increasingly reported worldwide 2.
- The antibiotic is often used in combination with other drugs, such as sulbactam, to enhance its effectiveness against multidrug-resistant A. baumannii strains 3, 4.
- Studies have shown that meropenem, in combination with polymyxin B, can be an effective treatment strategy against carbapenem-resistant A. baumannii, with intensified meropenem dosing resulting in complete eradication of the bacteria in some cases 5.
- However, there have been reports of meropenem-resistant A. baumannii outbreaks, highlighting the need for careful monitoring of antibiotic resistance patterns and the importance of infection control measures in healthcare settings 6.
Meropenem Resistance in A. baumannii
- Resistance to meropenem in A. baumannii can be mediated by various mechanisms, including the expression of metallo-beta-lactamase enzymes 6.
- The emergence of meropenem-resistant A. baumannii strains has been associated with increased morbidity and mortality, emphasizing the need for effective treatment strategies and infection control measures 2, 6.
- Combination therapy with meropenem and other antibiotics, such as sulbactam or polymyxin B, may be an effective approach to overcome resistance and improve treatment outcomes 3, 5, 4.