Zavicefta (Ceftazidime-Avibactam) Has NO Activity Against MRSA
Zavicefta (ceftazidime-avibactam) is NOT effective against MRSA and should never be used for suspected or confirmed MRSA infections. This agent is specifically designed for multidrug-resistant Gram-negative bacteria and lacks activity against Gram-positive organisms, including both methicillin-susceptible and methicillin-resistant Staphylococcus aureus 1, 2.
Spectrum of Activity
Ceftazidime-avibactam is a β-lactam/β-lactamase inhibitor combination with the following characteristics:
Excellent activity against Gram-negative pathogens including extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, Klebsiella pneumoniae carbapenemase (KPC)-producing organisms, AmpC-producing bacteria, and multidrug-resistant Pseudomonas aeruginosa 1, 2
NO activity against Gram-positive organisms including MRSA, MSSA, or other staphylococcal species 1, 2
NOT active against metallo-β-lactamase-producing strains 1
Appropriate Anti-MRSA Agents
When MRSA coverage is required, the following agents should be used instead:
Intravenous Options for MRSA:
- Vancomycin 15 mg/kg IV q12h (first-line for bacteremia and endocarditis) 3
- Daptomycin 6-10 mg/kg IV once daily (alternative for bacteremia; higher doses of 8-10 mg/kg recommended by experts) 3
- Linezolid 600 mg IV/PO q12h (superior to vancomycin for skin/soft tissue infections) 3
- Ceftaroline 600 mg IV q12h (advanced cephalosporin with MRSA activity) 3
- Dalbavancin 1000 mg once, then 500 mg after 1 week (long-acting lipoglycopeptide) 3
Oral Options for MRSA:
- Trimethoprim-sulfamethoxazole 160/800 mg q12h 3
- Doxycycline 100 mg q12h 3
- Linezolid 600 mg q12h 3
- Clindamycin 300-600 mg q8h (if local resistance <10%) 3
Critical Clinical Pitfall
The most dangerous error would be assuming carbapenem or cephalosporin activity against MRSA based on in vitro data or structural similarities. Ceftazidime-avibactam, like meropenem and other carbapenems, requires the addition of vancomycin or linezolid when MRSA coverage is needed 4. Failure to recognize this can lead to treatment failure and increased mortality 4.
When Zavicefta IS Appropriate
Ceftazidime-avibactam should be reserved for:
- Complicated urinary tract infections caused by resistant Gram-negative organisms 1, 5
- Complicated intra-abdominal infections (with metronidazole for anaerobic coverage) 1, 2, 5
- Hospital-acquired/ventilator-associated pneumonia from MDR Gram-negatives 1, 5
- Multidrug-resistant Pseudomonas aeruginosa infections (demonstrated lower mortality compared to other agents) 6
- KPC-producing Enterobacteriaceae 1, 2
The real-world OZAVIE cohort demonstrated 79% global success and 63.4% therapeutic success rates for these appropriate indications, with 20.2% 28-day mortality 5.