the broad sword
The broadest spectrum beta-lactams. Reserved for ESBL organisms, polymicrobial severe sepsis, and febrile neutropenia.
spectrum
- Covers: Gram positives (MSSA, Strep), Gram Negatives (including ESBL), Anaerobes.
- Gaps: MRSA, VRE, C. difficile, Stenotrophomonas.
agents
1. meropenem / imipenem
- Role: Nosocomial sepsis, Febrile Neutropenia, Meningitis (Meropenem preferred - lower seizure risk).
- Dosing: Renal adjustment required.
- Imipenem Nuance: Co-formulated with Cilastatin (prevents renal breakdown). Slightly higher risk of seizures (avoid in meningitis/renal failure/CNS pathology).
2. ertapenem
- The Exception: “The hole in the doughnut.”
- Does NOT cover: Pseudomonas, Acinetobacter, Enterococcus.
- Role: ESBL infections requiring once-daily dosing (outpatient IV therapy - OPAT).
penicillin allergy
Cross-reactivity with Penicillins is low (<1%). Safe to use in non-anaphylactic penicillin allergy.