23. The ID:IOTS guide to Carbapenems

Carbapenems represent a critical class of beta-lactam antibiotics characterized by a carbon atom at position one and a lack of large side chains, rendering them less allergenic than penicillins. While Meropenem serves as the clinical standard, the class includes Ertapenem, Imipenem-cilastatin, and Doripenem, each with distinct spectrums and dosing requirements. These agents provide broad coverage against gram-positive, gram-negative, and anaerobic organisms, though they lack activity against MRSA, Enterococci, and atypical pathogens. Intrinsic resistance, such as the "STAY ALERT" group—Stenotrophomonas, Aeromonas, and Elizabethkingia—limits their utility. Because they are reserve antibiotics, stewardship is paramount to prevent the emergence of carbapenemase-producing organisms. Clinical use requires careful consideration of infection severity, as these drugs are often reserved for ESBL or AmpC-producing organisms, with side effects ranging from gastrointestinal distress to lowered seizure thresholds in intensive care settings.